TY - JOUR A1 - Walter, J. A1 - Hamann, Göran A1 - Lück, Erika A1 - Klingenfuss, C. A1 - Zeitz, Jutta T1 - Stratigraphy and soil properties of fens: Geophysical case studies from northeastern Germany JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - The determination of the total carbon storage of peatlands is of high relevance in the context of climate-change mitigation efforts. This determination relies on data about stratigraphy and peat properties, which are conventionally collected by coring. Ground-penetrating radar (GPR) and electrical resistivity imaging (ERI) can support these point data by providing subsoil information in two-dimensional cross-sections. In this study, GPR and ERI were conducted at two groundwater-fed fen sites located in the temperate zone in north-east Germany. The fens of this region are embedded in low conductive glacial sand and are characterised by thick layers of gyttja, which can be either mineral or organic. The two study sites are representative of this region with respect to stratigraphy (total thickness, peat and gyttja types) and ecological conditions (pH-value, trophic condition). The aim of this study is to assess the suitability of GPR and ERI to detect stratigraphy and peat properties under these characteristic site conditions. Results show that GPR clearly detects the interfaces between (i) Carex and brown-moss peat, (ii) brown-moss peat and organic gyttja, (iii) organic- and mineral gyttja, and (iv) mineral gyttja and the parent material (glacial sand). These layers differ in bulk density and the related organic matter content. ERI, however, does not delineate these layers; rather it delineates regions of varying properties. At our base-rich site, pore fluid conductivity and cation.exchange capacity are the main factors that determine peat electrical conductivity (reverse of resistivity), whereas organic matter and water content are most influential at the more acidic site. Thus the correlation between peat properties and electrical conductivity are driven by site-specific conditions, which are mainly determined by the solute load in the groundwater at fens. When the total organic deposits exceed a thickness of 5 m, the depth of investigation by GPR is limited due to increasing attenuation. This is not a limiting factor for ERI, where the transition from organic deposits to glacial sand is visible at both sites. Due to these specific sensitivities, a combined application of GPR and ERI meets the demand for up-to-date information on carbon storage of peatlands, which is, moreover, very site-specific because of the inherent variety of ecological conditions and stratigraphy between peatlands in general and between fens and bogs in particular. (C) 2016 Elsevier B.V. All rights reserved. KW - Fen stratigraphy KW - Peat properties KW - Gyttja KW - Ground penetrating radar KW - Electrical conductivity KW - Electrical resistivity imaging Y1 - 2016 U6 - https://doi.org/10.1016/j.catena.2016.02.028 SN - 0341-8162 SN - 1872-6887 VL - 142 SP - 112 EP - 125 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Guillemoteau, Julien A1 - Simon, Francois-Xavier A1 - Lück, Erika A1 - Tronicke, Jens T1 - 1D sequential inversion of portable multi-configuration electromagnetic induction data JF - Near surface geophysics N2 - We present an algorithm that performs sequentially one-dimensional inversion of subsurface magnetic permeability and electrical conductivity by using multi-configuration electromagnetic induction sensor data. The presented method is based on the conversion of the in-phase and out-of-phase data into effective magnetic permeability and electrical conductivity of the equivalent homogeneous half-space. In the case of small-offset systems, such as portable electromagnetic induction sensors, for which in-phase and out-of-phase data are moderately coupled, the effective half-space magnetic permeability and electrical conductivity can be inverted sequentially within an iterative scheme. We test and evaluate the proposed inversion strategy using synthetic and field examples. First, we apply it to synthetic data for some highly magnetic environments. Then, the method is tested on real field data acquired in a basaltic environment to image a formation of archaeological interest. These examples demonstrate that a joint interpretation of in-phase and out-of-phase data leads to a better characterisation of the subsurface in magnetic environments such as volcanic areas. Y1 - 2016 U6 - https://doi.org/10.3997/1873-0604.2016029 SN - 1569-4445 SN - 1873-0604 VL - 14 SP - 423 EP - 432 PB - Wiley-VCH CY - Houten ER - TY - JOUR A1 - Salamat, Mona A1 - Zare, Mehdi A1 - Holschneider, Matthias A1 - Zöller, Gert T1 - Calculation of Confidence Intervals for the Maximum Magnitude of Earthquakes in Different Seismotectonic Zones of Iran JF - Pure and applied geophysics N2 - The problem of estimating the maximum possible earthquake magnitude m(max) has attracted growing attention in recent years. Due to sparse data, the role of uncertainties becomes crucial. In this work, we determine the uncertainties related to the maximum magnitude in terms of confidence intervals. Using an earthquake catalog of Iran, m(max) is estimated for different predefined levels of confidence in six seismotectonic zones. Assuming the doubly truncated Gutenberg-Richter distribution as a statistical model for earthquake magnitudes, confidence intervals for the maximum possible magnitude of earthquakes are calculated in each zone. While the lower limit of the confidence interval is the magnitude of the maximum observed event, the upper limit is calculated from the catalog and the statistical model. For this aim, we use the original catalog which no declustering methods applied on as well as a declustered version of the catalog. Based on the study by Holschneider et al. (Bull Seismol Soc Am 101(4): 1649-1659, 2011), the confidence interval for m(max) is frequently unbounded, especially if high levels of confidence are required. In this case, no information is gained from the data. Therefore, we elaborate for which settings finite confidence levels are obtained. In this work, Iran is divided into six seismotectonic zones, namely Alborz, Azerbaijan, Zagros, Makran, Kopet Dagh, Central Iran. Although calculations of the confidence interval in Central Iran and Zagros seismotectonic zones are relatively acceptable for meaningful levels of confidence, results in Kopet Dagh, Alborz, Azerbaijan and Makran are not that much promising. The results indicate that estimating mmax from an earthquake catalog for reasonable levels of confidence alone is almost impossible. KW - Maximum magnitude of earthquake KW - Level of confidence KW - Confidence interval Y1 - 2016 U6 - https://doi.org/10.1007/s00024-016-1418-5 SN - 0033-4553 SN - 1420-9136 VL - 174 SP - 763 EP - 777 PB - Springer CY - Basel ER - TY - JOUR A1 - Budke, Alexandra A1 - Kuckuck, Miriam A1 - Wienecke, Maik ED - Budke, Alexandra ED - Kuckuck, Miriam T1 - Realisierungen der Politischen Bildung im Geographieunterricht BT - Ergebnisse einer Interviewstudie mit Geographielehrkräften JF - Politische Bildung im Geographieunterricht Y1 - 2016 SN - 978-3-515-11325-0 SN - 978-3-515-11321-2 SP - 155 EP - 165 PB - Steiner CY - Stuttgart ER - TY - JOUR A1 - Hundecha, Yeshewatesfa A1 - Sunyer, Maria A. A1 - Lawrence, Deborah A1 - Madsen, Henrik A1 - Willems, Patrick A1 - Bürger, Gerd A1 - Kriauciuniene, Jurate A1 - Loukas, Athanasios A1 - Martinkova, Marta A1 - Osuch, Marzena A1 - Vasiliades, Lampros A1 - von Christierson, Birgitte A1 - Vormoor, Klaus Josef A1 - Yuecel, Ismail T1 - Inter-comparison of statistical downscaling methods for projection of extreme flow indices across Europe JF - Journal of hydrology N2 - The effect of methods of statistical downscaling of daily precipitation on changes in extreme flow indices under a plausible future climate change scenario was investigated in 11 catchments selected from 9 countries in different parts of Europe. The catchments vary from 67 to 6171 km(2) in size and cover different climate zones. 15 regional climate model outputs and 8 different statistical downscaling methods, which are broadly categorized as change factor and bias correction based methods, were used for the comparative analyses. Different hydrological models were implemented in different catchments to simulate daily runoff. A set of flood indices were derived from daily flows and their changes have been evaluated by comparing their values derived from simulations corresponding to the current and future climate. Most of the implemented downscaling methods project an increase in the extreme flow indices in most of the catchments. The catchments where the extremes are expected to increase have a rainfall dominated flood regime. In these catchments, the downscaling methods also project an increase in the extreme precipitation in the seasons when the extreme flows occur. In catchments where the flooding is mainly caused by spring/summer snowmelt, the downscaling methods project a decrease in the extreme flows in three of the four catchments considered. A major portion of the variability in the projected changes in the extreme flow indices is attributable to the variability of the climate model ensemble, although the statistical downscaling methods contribute 35-60% of the total variance. (C) 2016 Elsevier B.V. All rights reserved. KW - Flooding KW - Statistical downscaling KW - Regional climate models KW - Climate change KW - Europe Y1 - 2016 U6 - https://doi.org/10.1016/j.jhydrol.2016.08.033 SN - 0022-1694 SN - 1879-2707 VL - 541 SP - 1273 EP - 1286 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vormoor, Klaus Josef A1 - Lawrence, Deborah A1 - Schlichting, Lena A1 - Wilson, Donna A1 - Wong, Wai Kwok T1 - Evidence for changes in the magnitude and frequency of observed rainfall vs. snowmelt driven floods in Norway JF - Journal of hydrology N2 - There is increasing evidence for recent changes in the intensity and frequency of heavy precipitation and in the number of days with snow cover in many parts of Norway. The question arises as to whether these changes are also discernable with respect to their impacts on the magnitude and frequency of flooding and on the processes producing high flows. In this study, we tested up to 211 catchments for trends in peak flow discharge series by applying the Mann-Kendall test and Poisson regression for three different time periods (1962-2012, 1972-2012, 1982-2012). Field-significance was tested using a bootstrap approach. Over threshold discharge events were classified into rainfall vs. snowmelt dominated floods, based on a simple water balance approach utilizing a nationwide 1 x 1 km(2) gridded data set with daily observed rainfall and simulated snowmelt data. Results suggest that trends in flood frequency are more pronounced than trends in flood magnitude and are more spatially consistent with observed changes in the hydrometeorological drivers. Increasing flood frequencies in southern and western Norway are mainly due to positive trends in the frequency of rainfall dominated events, while decreasing flood frequencies in northern Norway are mainly the result of negative trends in the frequency of snowmelt dominated floods. Negative trends in flood magnitude are found more often than positive trends, and the regional patterns of significant trends reflect differences in the flood generating processes (FGPs). The results illustrate the benefit of distinguishing FGPs rather than simply applying seasonal analyses. The results further suggest that rainfall has generally gained an increasing importance for the generation of floods in Norway, while the role of snowmelt has been decreasing and the timing of snowmelt dominated floods has become earlier. (C) 2016 Elsevier B.V. All rights reserved. KW - Peak flow trends KW - Peak-over-threshold KW - Flood generating processes KW - Rainfall floods KW - Snowmelt floods KW - Climate change Y1 - 2016 U6 - https://doi.org/10.1016/j.jhydrol.2016.03.066 SN - 0022-1694 SN - 1879-2707 VL - 538 SP - 33 EP - 48 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Abdrakhmatov, Kanatbek E. A1 - Walker, R. T. A1 - Campbell, G. E. A1 - Carr, A. S. A1 - Elliott, A. A1 - Hillemann, Christian A1 - Hollingsworth, J. A1 - Landgraf, Angela A1 - Mackenzie, D. A1 - Mukambayev, A. A1 - Rizza, M. A1 - Sloan, R. A. T1 - Multisegment rupture in the 11 July 1889 Chilik earthquake (M-w 8.0-8.3), Kazakh Tien Shan, interpreted from remote sensing, field survey, and paleoseismic trenching JF - Journal of geophysical research : Solid earth N2 - The 11 July 1889 Chilik earthquake (M-w 8.0-8.3) forms part of a remarkable sequence of large earthquakes in the late nineteenth and early twentieth centuries in the northern Tien Shan. Despite its importance, the source of the 1889 earthquake remains unknown, though the macroseismic epicenter is sited in the Chilik valley, similar to 100 km southeast of Almaty, Kazakhstan (similar to 2 million population). Several short fault segments that have been inferred to have ruptured in 1889 are too short on their own to account for the estimated magnitude. In this paper we perform detailed surveying and trenching of the similar to 30 km long Saty fault, one of the previously inferred sources, and find that it was formed in a single earthquake within the last 700 years, involving surface slip of up to 10 m. The scarp-forming event, likely to be the 1889 earthquake, was the only surface-rupturing event for at least 5000 years and potentially for much longer. From satellite imagery we extend the mapped length of fresh scarps within the 1889 epicentral zone to a total of similar to 175 km, which we also suggest as candidate ruptures from the 1889 earthquake. The 175 km of rupture involves conjugate oblique left-lateral and right-lateral slip on three separate faults, with step overs of several kilometers between them. All three faults were essentially invisible in the Holocene geomorphology prior to the last slip. The recurrence interval between large earthquakes on any of these faults, and presumably on other faults of the Tien Shan, may be longer than the timescale over which the landscape is reset, providing a challenge for delineating sources of future hazard. Y1 - 2016 U6 - https://doi.org/10.1002/2015JB012763 SN - 2169-9313 SN - 2169-9356 VL - 121 SP - 4615 EP - 4640 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Li, Kai A1 - Liu, Xingqi A1 - Herzschuh, Ulrike A1 - Wang, Yongbo T1 - Rapid climate fluctuations over the past millennium: evidence from a lacustrine record of Basomtso Lake, southeastern Tibetan Plateau JF - Scientific reports N2 - Abrupt climate changes and fluctuations over short time scales are superimposed on long-term climate changes. Understanding rapid climate fluctuations at the decadal time scale over the past millennium will enhance our understanding of patterns of climate variability and aid in forecasting climate changes in the future. In this study, climate changes on the southeastern Tibetan Plateau over the past millennium were determined from a 4.82-m-long sediment core from Basomtso Lake. At the centennial time scale, the Medieval Climate Anomaly (MCA), Little Ice Age (LIA) and Current Warm Period (CWP) are distinct in the Basomtso region. Rapid climate fluctuations inferred from five episodes with higher sediment input and likely warmer conditions, as well as seven episodes with lower sediment input and likely colder conditions, were well preserved in our record. These episodes with higher and lower sediment input are characterized by abrupt climate changes and short time durations. Spectral analysis indicates that the climate variations at the centennial scale on the southeastern Tibetan Plateau are influenced by solar activity during the past millennium. Y1 - 2016 U6 - https://doi.org/10.1038/srep24806 SN - 2045-2322 VL - 6 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Lozano-Parra, Javier A1 - van Schaik, N. Loes M. B. A1 - Schnabel, Susanne A1 - Gomez-Gutierrez, Alvaro T1 - Soil moisture dynamics at high temporal resolution in a semiarid Mediterranean watershed with scattered tree cover JF - Hydrological processes N2 - Subsurface water flows play a key role in the distribution of water and solutes and thereby in the water availability for plants. However, the characterization of different flow processes (i.e.matrix and preferential flow), the frequency and factors that cause them, is relatively rare. This characterization enables a better understanding of spatio-temporal variability of water resources and allows for the design of models to be improved. Using a method based on the time derivative of soil moisture variation known as maximum wetting slope, types of soil wetting processes were classified and quantified. For this, capacitance sensors, which registered the volumetric water content at high temporal resolution (30min) for more than two hydrological years, were installed at different depths and placed in soil moisture stations with different vegetation covers, lithology and topographic position. Results indicated that there is a general behaviour or pattern of soil moisture dynamics in the catchment with a dominant occurrence of slower soil wetting processes (>50%), caused by matrix flows, and a low occurrence of those faster processes (<30%), originated by preferential flows. Nevertheless, when the total volume of water is considered, preferential flow becomes the dominant process, so that the ecological role of both flow types becomes prominent in water-limited environments. Statistical multivariate analyses based on data-mining techniques proved that although both flow types depend on variables associated with precipitation and antecedent soil moisture conditions, faster soil wetting processes are mainly related to variables such as rainfall intensity and topography, while slower soil wetting processes are related to flow velocity, soils or vegetation. Copyright (c) 2015 John Wiley & Sons, Ltd. KW - soil moisture dynamics KW - high temporal resolution KW - capacitive sensors KW - water-limited environment KW - MARS Y1 - 2016 U6 - https://doi.org/10.1002/hyp.10694 SN - 0885-6087 SN - 1099-1085 VL - 30 SP - 1155 EP - 1170 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Krueger, Tobias A1 - Maynard, Carly A1 - Carr, Gemma A1 - Bruns, Antje A1 - Müller, Eva Nora A1 - Lane, Stuart T1 - A transdisciplinary account of water research JF - Wiley Interdisciplinary Reviews : Water N2 - Water research is introduced from the combined perspectives of natural and social science and cases of citizen and stakeholder coproduction of knowledge. Using the overarching notion of transdisciplinarity, we examine how interdisciplinary and participatory water research has taken place and could be developed further. It becomes apparent that water knowledge is produced widely within society, across certified disciplinary experts and noncertified expert stakeholders and citizens. However, understanding and management interventions may remain partial, or even conflicting, as much research across and between traditional disciplines has failed to integrate disciplinary paradigms due to philosophical, methodological, and communication barriers. We argue for more agonistic relationships that challenge both certified and noncertified knowledge productively. These should include examination of how water research itself embeds and is embedded in social context and performs political work. While case studies of the cultural and political economy of water knowledge exist, we need more empirical evidence on how exactly culture, politics, and economics have shaped this knowledge and how and at what junctures this could have turned out differently. We may thus channel the coproductionist critique productively to bring perspectives, alternative knowledges, and implications into water politics where they were not previously considered; in an attempt to counter potential lock-in to particular water policies and technologies that may be inequitable, unsustainable, or unacceptable. While engaging explicitly with politics, transdisciplinary water research should remain attentive to closing down moments in the research process, such as framings, path-dependencies, vested interests, researchers’ positionalities, power, and scale. Y1 - 2016 U6 - https://doi.org/10.1002/wat2.1132 SN - 2049-1948 VL - 3 SP - 369 EP - 389 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Yepes, Hugo A1 - Audin, Laurence A1 - Alvarado, Alexandra A1 - Beauval, Celine A1 - Aguilar, Jorge A1 - Font, Yvonne A1 - Cotton, Fabrice Pierre T1 - A new view for the geodynamics of Ecuador: Implication in seismogenic source definition and seismic hazard assessment JF - Tectonics N2 - A new view of Ecuador's complex geodynamics has been developed in the course of modeling seismic source zones for probabilistic seismic hazard analysis. This study focuses on two aspects of the plates' interaction at a continental scale: (a) age-related differences in rheology between Farallon and Nazca plates—marked by the Grijalva rifted margin and its inland projection—as they subduct underneath central Ecuador, and (b) the rapidly changing convergence obliquity resulting from the convex shape of the South American northwestern continental margin. Both conditions satisfactorily explain several characteristics of the observed seismicity and of the interseismic coupling. Intermediate-depth seismicity reveals a severe flexure in the Farallon slab as it dips and contorts at depth, originating the El Puyo seismic cluster. The two slabs position and geometry below continental Ecuador also correlate with surface expressions observable in the local and regional geology and tectonics. The interseismic coupling is weak and shallow south of the Grijalva rifted margin and increases northward, with a heterogeneous pattern locally associated to the Carnegie ridge subduction. High convergence obliquity is responsible for the North Andean Block northeastward movement along localized fault systems. The Cosanga and Pallatanga fault segments of the North Andean Block-South American boundary concentrate most of the seismic moment release in continental Ecuador. Other inner block faults located along the western border of the inter-Andean Depression also show a high rate of moderate-size earthquake production. Finally, a total of 19 seismic source zones were modeled in accordance with the proposed geodynamic and neotectonic scheme. Y1 - 2016 U6 - https://doi.org/10.1002/2015TC003941 SN - 0278-7407 SN - 1944-9194 VL - 35 SP - 1249 EP - 1279 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Donges, Jonathan Friedemann A1 - Schleussner, C. -F. A1 - Siegmund, Jonatan F. A1 - Donner, Reik Volker T1 - Event coincidence analysis for quantifying statistical interrelationships between event time series JF - European physical journal special topics N2 - Studying event time series is a powerful approach for analyzing the dynamics of complex dynamical systems in many fields of science. In this paper, we describe the method of event coincidence analysis to provide a framework for quantifying the strength, directionality and time lag of statistical interrelationships between event series. Event coincidence analysis allows to formulate and test null hypotheses on the origin of the observed interrelationships including tests based on Poisson processes or, more generally, stochastic point processes with a prescribed inter-event time distribution and other higher-order properties. Applying the framework to country-level observational data yields evidence that flood events have acted as triggers of epidemic outbreaks globally since the 1950s. Facing projected future changes in the statistics of climatic extreme events, statistical techniques such as event coincidence analysis will be relevant for investigating the impacts of anthropogenic climate change on human societies and ecosystems worldwide. Y1 - 2016 U6 - https://doi.org/10.1140/epjst/e2015-50233-y SN - 1951-6355 SN - 1951-6401 VL - 225 SP - 471 EP - 487 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Waha, Katharina A1 - Zipf, Birgit A1 - Kurukulasuriya, Pradeep A1 - Hassan, Rashid M. T1 - An agricultural survey for more than 9,500 African households JF - Scientific Data N2 - Surveys for more than 9,500 households were conducted in the growing seasons 2002/2003 or 2003/2004 in eleven African countries: Burkina Faso, Cameroon, Ghana, Niger and Senegal in western Africa; Egypt in northern Africa; Ethiopia and Kenya in eastern Africa; South Africa, Zambia and Zimbabwe in southern Africa. Households were chosen randomly in districts that are representative for key agro-climatic zones and farming systems. The data set specifies farming systems characteristics that can help inform about the importance of each system for a country’s agricultural production and its ability to cope with short- and long-term climate changes or extreme weather events. Further it informs about the location of smallholders and vulnerable systems and permits benchmarking agricultural systems characteristics. Y1 - 2016 U6 - https://doi.org/10.1038/sdata.2016.20 SN - 2052-4463 VL - 3 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Schulz, Katharina A1 - Voigt, Karsten A1 - Beusch, Christine A1 - Almeida-Cortez, Jarcilene S. A1 - Kowarik, Ingo A1 - Walz, Ariane A1 - Cierjacks, Arne T1 - Grazing deteriorates the soil carbon stocks of Caatinga forest ecosystems in Brazil JF - Forest ecology and management N2 - Grazing by domestic ungulates can have substantial impacts on forests in arid and semi-arid regions, possibly including severe loss of carbon from the soil. Predicting net livestock impacts on soil organic carbon stocks remains challenging, however, due to the dependence on animal loads and on soil and environmental parameters. The objective of this study was to better understand grazing effects on soil organic carbon in seasonal tropical dry forests of north-eastern Brazil (Caatinga) by quantifying carbon stocks of the upper soil profile (0–5 cm depth) and greater soil depths (>5 cm depth down to bedrock) along a gradient of grazing intensity while accounting for other influencing factors such as soil texture, vegetation, landscape topography, and water availability. We analysed soil organic carbon, soil clay content, altitude above sea level, soil depth to bedrock, distance to the nearest permanent water body, species diversity of perennial plants and aboveground biomass on 45 study plots located in the vicinity of the Itaparica Reservoir, Pernambuco, Brazil. Livestock (mainly goats and cattle) are unevenly distributed in the studied ecosystem, thus grazing intensity was accounted for based on the weight of livestock droppings per square metre and classified as no or light, intermediate, or heavy grazing. The mean soil organic carbon in the area was 16.86 ± 1.28 Mg ha−1 C with approximately one-quarter found in the upper 5 cm of the soil profile (4.14 ± 0.43 Mg ha−1 C) and the remainder (12.57 ± 0.97 Mg ha−1 C) in greater soil depths (>5 cm). Heavy grazing led to significantly lower soil organic carbon stocks in the upper 5 cm, whereas no effect on soil organic carbon of the soil overall or in greater soil depths was detectable. The soil’s clay content and the altitude proved to be the most relevant factors influencing overall soil organic carbon stocks and those in greater soil depths (>5 cm). Our findings suggest that grazing causes substantial release of carbon from Brazilian dry forest soils, which should be addressed through improved grazing management via a legally compulsory rotation system. This would ultimately contribute to the conservation of a unique forest system and associated ecosystem services. KW - Carbon cycle KW - Degradation KW - Desertification KW - Livestock KW - Semi-arid KW - Soil Y1 - 2016 U6 - https://doi.org/10.1016/j.foreco.2016.02.011 SN - 0378-1127 SN - 1872-7042 VL - 367 SP - 62 EP - 70 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Melnick, Daniel T1 - Rise of the central Andean coast by earthquakes straddling the Moho JF - Nature geoscience N2 - Surface movements during the largest subduction zone earthquakes commonly drown coastlines. Yet, on geological timescales, coastlines above subduction zones uplift. Here I use a morphometric analysis combined with a numerical model of landscape evolution to estimate uplift rates along the central Andean rasa-a low-relief coastal surface bounded by a steep cliff formed by wave erosion. I find that the rasa has experienced steady uplift of 0.13 +/- 0.04 mm per year along a stretch of more than 2,000 km in length, during the Quaternary. These long-term uplift rates do not correlate with Global Positioning System (GPS) measurements of interseismic movements over the decadal scale, which implies that permanent uplift is not predominantly accumulated during the interseismic period. Instead, the rate of rasa uplift correlates with slip during earthquakes straddling the crust-mantle transition, the Moho. Such deeper earthquakes with magnitude 7 to 8 that occurred between 1995 and 2012 resulted in decimetres of coastal uplift. Slip during these earthquakes is located below the locked portion of the plate interface, and therefore may translate into permanent deformation of the overlying plate, where it causes uplift of the coastline. Thus, lower parts of the plate boundary are stably segmented over hundreds to millions of years. I suggest the coastline marks the surface expression of the transition between the shallow, locked seismogenic domain and the deeper, conditionally stable domain where modest earthquakes build up topography. Y1 - 2016 U6 - https://doi.org/10.1038/NGEO2683 SN - 1752-0894 SN - 1752-0908 VL - 9 SP - 401 EP - + PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Licht, Alexis A1 - Pullen, A. A1 - Kapp, P. A1 - Abell, Jordan A1 - Giesler, N. T1 - Eolian cannibalism: Reworked loess and fluvial sediment as the main sources of the Chinese Loess Plateau JF - Geological Society of America bulletin N2 - The loess and paleosol sequences of the Chinese Loess Plateau are composed of Quaternary dust, the origin of which has been the subject of considerable debate. Some recent U-Pb geochronological studies of eolian zircons have proposed the existence of two major wind pathways: from the north and northwest, through the Badan Jaran, Tengger, and Mu Us Deserts during interglacials, and from the west, through the Qaidam Basin during glacials. Others have emphasized the importance of Yellow River sediment supply in the Chinese Loess Plateau sediment budget. However, tracking dust source regions through U-Pb dating in a statistically robust manner is particularly complex given the similar age peaks in the age probability distributions of potential source regions in Central Asia. This paper presents 2410 new U-Pb ages of detrital zircons from wind-eroded strata, Quaternary eolian deposits, and modern river sands in central China in order to increase the robustness and the spatial resolution of zircon age distributions in dust source regions. We then propose a new mixture modeling technique to statistically address the contribution of these different sources to the Chinese Loess Plateau sedimentary budget. Our contribution estimates indicate that eolian supply to the Chinese Loess Plateau is dominated (60%-70%) by reworking of Yellow River sediment. Moreover, evidence of Qaidam Basin-sourced zircons (15%-20%) in both loess (glacial) and paleosol (interglacial) layers corroborates the existence of an erosive wind pathway through the Qaidam Basin during glacials and implies that a substantial portion of the interglacial dust is recycled from older glacial loess. We propose that sediment reworking of Yellow River sediment and older loess deposits by wind on the Chinese Loess Plateau homogenized the eolian zircon populations toward a glacial provenance due to higher (2-20 times) dust accumulation rates during glacials. These findings suggest that the Chinese Loess Plateau has evolved as a more dynamic landform than previous thought, where wind deflation, fluvial input, lateral transport, and accumulation of sediment are equally important. These internal reworking effects would then significantly bias the paleoclimatic interpretations based on eolian dust properties of the Chinese Loess Plateau. Y1 - 2016 U6 - https://doi.org/10.1130/B31375.1 SN - 0016-7606 SN - 1943-2674 VL - 128 SP - 944 EP - 956 PB - American Institute of Physics CY - Boulder ER - TY - JOUR A1 - Herzschuh, Ulrike A1 - Birks, H. John B. A1 - Laepple, Thomas A1 - Andreev, Andrei A1 - Melles, Martin A1 - Brigham-Grette, Julie T1 - Glacial legacies on interglacial vegetation at the Pliocene-Pleistocene transition in NE Asia JF - Nature Communications N2 - Broad-scale climate control of vegetation is widely assumed. Vegetation-climate lags are generally thought to have lasted no more than a few centuries. Here our palaeoecological study challenges this concept over glacial–interglacial timescales. Through multivariate analyses of pollen assemblages from Lake El’gygytgyn, Russian Far East and other data we show that interglacial vegetation during the Plio-Pleistocene transition mainly reflects conditions of the preceding glacial instead of contemporary interglacial climate. Vegetation–climate disequilibrium may persist for several millennia, related to the combined effects of permafrost persistence, distant glacial refugia and fire. In contrast, no effects from the preceding interglacial on glacial vegetation are detected. We propose that disequilibrium was stronger during the Plio-Pleistocene transition than during the Mid-Pliocene Warm Period when, in addition to climate, herbivory was important. By analogy to the past, we suggest today’s widespread larch ecosystem on permafrost is not in climate equilibrium. Vegetation-based reconstructions of interglacial climates used to assess atmospheric CO2–temperature relationships may thus yield misleading simulations of past global climate sensitivity. Y1 - 2016 U6 - https://doi.org/10.1038/ncomms11967 SN - 2041-1723 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Kawashima, Chiho A1 - Ito, Nozomi A1 - Nagashima, Shuntarou A1 - Matsui, Motozumi A1 - Sawada, Kumiko A1 - Schweigert, Florian J. A1 - Miyamoto, Akio A1 - Kida, Katsuya T1 - Influence of hepatic load from far-off dry period to early postpartum period on the first postpartum ovulation and accompanying subsequent fertility in dairy cows JF - The journal of reproduction and development : official journal of the Japanese Society of Animal Reproduction N2 - The aim of the present study was to investigate nutritional and metabolic parameters during the dry and early postpartum periods of ovulatory and anovulatory cows, as well as their postpartum reproductive performance. Blood samples from 20 multiparous Holstein cows were collected once a week from the far-off dry period to 3 weeks postpartum. Early postpartum (0-3 weeks) ovulation was confirmed using plasma progesterone concentration profiles, and cows were considered ovulatory if they had resumed luteal activity by this point (n = 9), whereas cows that had not were considered anovulatory (n = 11). Data from the ovulatory and anovulatory cows were analyzed separately for the far-off dry period (7-4 weeks prepartum), the close-up dry period (3-1 weeks prepartum), and the early postpartum period (0-3 weeks). Serum gamma-glutamyl transpeptidase activity (far-off, P = 0.065; close-up, P = 0.051; and early postpartum, P = 0.030) and aspartate aminotransferase (close-up, P = 0.050 and early postpartum, P = 0.087) activities were higher in anovulatory than in ovulatory cows. The days open period was longer (P = 0.019) in anovulatory than in ovulatory cows, and the number of artificial inseminations per conception (P = 0.025) was greater. In conclusion, we found that continuously high gamma-glutamyl transpeptidase activities in serum, which may be induced by liver disorders, prevent subsequent ovulation and affect subsequent fertility, even if cows obtain sufficient ovulation-related energy and beta-carotene. KW - Dairy cow KW - First ovulation KW - Hepatic enzyme KW - Liver function KW - Reproductive performance Y1 - 2016 SN - 0916-8818 VL - 62 SP - 289 EP - 295 PB - Utha State University CY - Tsukuba ER - TY - JOUR A1 - Kottmeier, Christoph A1 - Agnon, Amotz A1 - Al-Halbouni, Djamil A1 - Alpert, Pinhas A1 - Corsmeier, Ulrich A1 - Dahm, Torsten A1 - Eshel, Adam A1 - Geyer, Stefan A1 - Haas, Michael A1 - Holohan, Eoghan A1 - Kalthoff, Norbert A1 - Kishcha, Pavel A1 - Krawczyk, Charlotte A1 - Lati, Joseph A1 - Laronne, Jonathan B. A1 - Lott, Friederike A1 - Mallast, Ulf A1 - Merz, Ralf A1 - Metzger, Jutta A1 - Mohsen, Ayman A1 - Morin, Efrat A1 - Nied, Manuela A1 - Roediger, Tino A1 - Salameh, Elias A1 - Sawarieh, Ali A1 - Shannak, Benbella A1 - Siebert, Christian A1 - Weber, Michael T1 - New perspectives on interdisciplinary earth science at the Dead Sea: The DESERVE project JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - The Dead Sea region has faced substantial environmental challenges in recent decades, including water resource scarcity, similar to 1 m annual decreases in the water level, sinkhole development, ascending-brine freshwater pollution, and seismic disturbance risks. Natural processes are significantly affected by human interference as well as by climate change and tectonic developments over the long term. To get a deep understanding of processes and their interactions, innovative scientific approaches that integrate disciplinary research and education are required. The research project DESERVE (Helmholtz Virtual Institute Dead Sea Research Venue) addresses these challenges in an interdisciplinary approach that includes geophysics, hydrology, and meteorology. The project is implemented by a consortium of scientific institutions in neighboring countries of the Dead Sea (Israel, Jordan, Palestine Territories) and participating German Helmholtz Centres (KIT, GFZ, UFZ). A new monitoring network of meteorological, hydrological, and seismic/geodynamic stations has been established, and extensive field research and numerical simulations have been undertaken. For the first time, innovative measurement and modeling techniques have been applied to the extreme conditions of the Dead Sea and its surroundings. The preliminary results show the potential of these methods. First time ever performed eddy covariance measurements give insight into the governing factors of Dead Sea evaporation. High-resolution bathymetric investigations reveal a strong correlation between submarine springs and neo-tectonic patterns. Based on detailed studies of stratigraphy and borehole information, the extension of the subsurface drainage basin of the Dead Sea is now reliably estimated. Originality has been achieved in monitoring flash floods in an arid basin at its outlet and simultaneously in tributaries, supplemented by spatio-temporal rainfall data. Low-altitude, high resolution photogrammetry, allied to satellite image analysis and to geophysical surveys (e.g. shear-wave reflections) has enabled a more detailed characterization of sinkhole morphology and temporal development and the possible subsurface controls thereon. All the above listed efforts and scientific results take place with the interdisciplinary education of young scientists. They are invited to attend joint thematic workshops and winter schools as well as to participate in field experiments. (C) 2015 The Authors. Published by Elsevier B.V. KW - Climate KW - Water balance KW - Flash floods KW - Seismicity KW - Sinkholes KW - Education Y1 - 2016 U6 - https://doi.org/10.1016/j.scitotenv.2015.12.003 SN - 0048-9697 SN - 1879-1026 VL - 544 SP - 1045 EP - 1058 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - McGee, David A1 - Winckler, Gisela A1 - Borunda, Alejandra A1 - Serno, Sascha A1 - Anderson, Robert F. A1 - Recasens, Cristina A1 - Bory, Aloys A1 - Gaiero, Diego A1 - Jaccard, Samuel L. A1 - Kaplan, Michael A1 - McManus, Jerry F. A1 - Revel, Marie A1 - Sun, Youbin T1 - Tracking eolian dust with helium and thorium: Impacts of grain size and provenance JF - Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society N2 - Reconstructions of the deposition rate of windblown mineral dust in ocean sediments offer an important means of tracking past climate changes and of assessing the radiative and biogeochemical impacts of dust in past climates. Dust flux estimates in ocean sediments have commonly been based on the operationally defined lithogenic fraction of sediment samples. More recently, dust fluxes have been estimated from measurements of helium and thorium, as rare isotopes of these elements (He-3 and Th-230) allow estimates of sediment flux, and the dominant isotopes (He-4 and Th-232) are uniquely associated with the lithogenic fraction of marine sediments. In order to improve the fidelity of dust flux reconstructions based on He and Th, we present a survey of He and Th concentrations in sediments from dust source areas in East Asia, Australia and South America. Our data show systematic relationships between He and Th concentrations and grain size, with He concentrations decreasing and Th concentrations increasing with decreasing grain size. We find consistent He and Th concentrations in the fine fraction (<5 mu m) of samples from East Asia, Australia and Central South America (Puna-Central West Argentina), with Th concentrations averaging 14 mu g/g and He concentrations averaging 2 mu cc STP/g. We recommend use of these values for estimating dust fluxes in sediments where dust is dominantly fine-grained, and suggest that previous studies may have systematically overestimated Th-based dust fluxes by 30%. Source areas in Patagonia appear to have lower He and Th contents than other regions, as fine fraction concentrations average 0.8 mu cc STP/g and 9 mu g/g for He-4 and Th-232, respectively. The impact of grain size on lithogenic He and Th concentrations should be taken into account in sediments proximal to dust sources where dust grain size may vary considerably. Our data also have important implications for the hosts of He in long-traveled dust and for the He-3/He-4 ratio used for terrigenous He in studies of extraterrestrial He in sediments and ice. We also investigate the use of He/Th ratios as a provenance tracer. Our results suggest differences in fine fraction He/Th ratios between East Asia, Australia, central South America and Patagonia, with ratios showing a positive relationship with the geological age of source rocks. He/Th ratios may thus provide useful provenance information, for example allowing separation of Patagonian sources from Puna-Central West Argentina or Australian dust sources. He/Th ratios in open-ocean marine sediments are similar to ratios in the fine fraction of upwind dust source areas. He/Th ratios in mid-latitude South Atlantic sediments suggest that dust in this region primarily derives from the Puna-Central West Argentina region (23-32 degrees S) rather than Patagonia (>38 degrees S). In the equatorial Pacific, He/Th ratios are much lower than in extratropical Pacific sediments or potential source areas measured as a part of this study (East Asia, South America, Australia) for reasons that are at present unclear, complicating their use as provenance tracers in this region. (C) 2015 Elsevier Ltd. All rights reserved. Y1 - 2016 U6 - https://doi.org/10.1016/j.gca.2015.11.023 SN - 0016-7037 SN - 1872-9533 VL - 175 SP - 47 EP - 67 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Gliege, Steffen A1 - Thomas, Bjoern D. A1 - Steidl, Jörg A1 - Hohenbrink, Tobias Ludwig A1 - Dietrich, Ottfried T1 - Modeling the Impact of Ditch Water Level Management on Stream-Aquifer Interactions JF - Water N2 - Decreasing groundwater levels in many parts of Germany and decreasing low flows in Central Europe have created a need for adaptation measures to stabilize the water balance and to increase low flows. The objective of our study was to estimate the impact of ditch water level management on stream-aquifer interactions in small lowland catchments of the mid-latitudes. The water balance of a ditch-irrigated area and fluxes between the subsurface and the adjacent stream were modeled for three runoff recession periods using the Hydrus-2D software package. The results showed that the subsurface flow to the stream was closely related to the difference between the water level in the ditch system and the stream. Evapotranspiration during the growing season additionally reduced base flow. It was crucial to stop irrigation during a recession period to decrease water withdrawal from the stream and enhance the base flow by draining the irrigated area. Mean fluxes to the stream were between 0.04 and 0.64 ls(-1) for the first 20 days of the low-flow periods. This only slightly increased the flow in the stream, whose mean was 57 ls(-1) during the period with the lowest flows. Larger areas would be necessary to effectively increase flows in mesoscale catchments. KW - ditch irrigation KW - adaption measure KW - Hydrus-2D KW - required minimum runoff KW - groundwater surface water interaction Y1 - 2016 U6 - https://doi.org/10.3390/w8030102 SN - 2073-4441 VL - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vogel, Sebastian A1 - Maerker, Michael A1 - Esposito, Domenico A1 - Seiler, Florian T1 - The Ancient Rural Settlement Structure in the Hinterland of Pompeii Inferred from Spatial Analysis and Predictive Modeling of Villae Rusticae JF - Geoarchaeology : an international journal N2 - Pompeii, buried by the explosive A. D. 79 eruption of Somma-Vesuvius, is one of the most studied ancient cities in the Roman world. However, until very recently, the rural settlement in its hinterland had been largely ignored by systematic archaeological research. The ancient landscape around Pompeii consisted of a dense network of Roman farms (villae rusticae). They are believed to have played a vital role in ancient rural life and economy and thus represented the interactive rural-urban relationship in the Sarno River plain. The systematic investigation of published work combined with new fieldwork has yielded a data set of 140 villae rusticae in the Sarno River plain. Geographic information system based spatial statistics as well as predictive modeling were applied to gain a more detailed understanding of the ancient rural settlement structure in relation to the underlying paleoenvironmental and socioeconomic conditions. A high-resolution pre-A. D. 79 paleolandscape model of the Sarno River plain was utilized. The aim of this paper is to address theoretical considerations, the methodological implementation, and the archaeological discussion of the analysis of the ancient rural settlements and agriculture around Pompeii. (C) 2016 Wiley Periodicals, Inc. Y1 - 2016 U6 - https://doi.org/10.1002/gea.21560 SN - 0883-6353 SN - 1520-6548 VL - 31 SP - 121 EP - 139 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Garofalo, F. A1 - Foti, S. A1 - Hollender, F. A1 - Bard, Pierre-Yves A1 - Cornou, C. A1 - Cox, B. R. A1 - Ohrnberger, Matthias A1 - Sicilia, D. A1 - Asten, M. A1 - Di Giulio, G. A1 - Forbriger, T. A1 - Guillier, B. A1 - Hayashi, K. A1 - Martin, A. A1 - Matsushima, Satoru A1 - Mercerat, D. A1 - Poggi, V. A1 - Yamanaka, H. T1 - InterPACIFIC project: Comparison of invasive and non-invasive methods for seismic site characterization. Part I: Intra-comparison of surface wave methods JF - Soil Dynamics and Earthquake Engineering N2 - The main scope of the InterPACIFIC (Intercomparison of methods for site parameter and velocity profile characterization) project is to assess the reliability of in-hole and surface-wave methods, used for estimating shear wave velocity. Three test-sites with different subsurface conditions were chosen: a soft soil, a stiff soil and a rock outcrop. This paper reports the surface-wave methods results. Specifically 14 teams of expert users analysed the same experimental surface-wave datasets, consisting of both passive and active data. Each team adopted their own strategy to retrieve the dispersion curve and the shear-wave velocity profile at each site. Despite different approaches, the dispersion curves are quite in agreement with each other. Conversely, the shear-wave velocity profiles show a certain variability that increases in correspondence of major stratigraphic interfaces. This larger variability is mainly due to non-uniqueness of the solution and lateral variability. As expected, the observed variability in V-s,V-30 estimatesis small, as solution non-uniqueness plays a limited role. (C) 2015 Elsevier Ltd. All rights reserved. KW - Surface-wave methods KW - Dispersion curve KW - Inversion KW - V-s,V-30 KW - Site characterization KW - MASW KW - Microtremors KW - Rayleigh waves KW - Geophysical methods Y1 - 2016 U6 - https://doi.org/10.1016/j.soildyn.2015.12.010 SN - 0267-7261 SN - 1879-341X VL - 82 SP - 222 EP - 240 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Gerke, Horst H. A1 - Rieckh, Helene A1 - Sommer, Michael T1 - Interactions between crop, water, and dissolved organic and inorganic carbon in a hummocky landscape with erosion-affected pedogenesis JF - Macromolecular rapid communications N2 - Hummocky soil landscapes are characterized by 3D spatial patterns of soil types that result from erosion-affected pedogenesis. Due to tillage and water erosion, truncated profiles have been formed at steep and mid slopes and colluvial soils at hollows, while intact profiles remained at plateau positions. Pedogenetic variations in soil horizons lead to spatial differences in the soil water balance at hillslope positions. Here, possible interactions between erosion affected soil properties, the water balances, and the crop growth and feedback effects of erosion on the leaching rates were assumed. The hypothesis was tested by water balance simulations comparing uniform with hillslope position-specific crop and root growths for soils at plateau, flat mid slope, steep slope, and hollow using the Hydrus-1D program. The boundary condition data were monitored at the CarboZALF-D experimental field site, which was cropped with perennial lucerne (Medicago sativa L.) in 2013 and 2014. Crop and root growth at the four hillslope positions was assumed proportional to observed leaf area index (LAI). Fluxes of dissolved organic and inorganic carbon (DOC, DIC) were obtained from simulated water fluxes and measured DOC and DIC concentrations. For the colluvic soil at hollow, the crop growth was initially highest and later limited by an increasing water table; here the predominately upward flow led to a net input in DIC and DOC. For the truncated soils at steep slopes, simulations support the hypothesis that reduced crop growth caused an increase in percolation and DIC leaching from the subsoil horizons, which in turn led to accelerated soil development and more soil variations along eroding hillslopes in arable soil landscapes. (C) 2015 Elsevier B.V. All rights reserved. KW - Hydrus-1D KW - LAI KW - Eroded soil types KW - Hillslope pedosequence KW - Soil C leaching KW - DOC vs. DIC KW - Soil water balance simulation KW - Root water uptake KW - Rooting depth Y1 - 2016 U6 - https://doi.org/10.1016/j.still.2015.09.003 SN - 0167-1987 SN - 1879-3444 VL - 156 SP - 230 EP - 244 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Carus, Jana A1 - Paul, Maike A1 - Schroeder, Boris T1 - Vegetation as self-adaptive coastal protection: Reduction of current velocity and morphologic plasticity of a brackish marsh pioneer JF - Ecology and evolution N2 - By reducing current velocity, tidal marsh vegetation can diminish storm surges and storm waves. Conversely, currents often exert high mechanical stresses onto the plants and hence affect vegetation structure and plant characteristics. In our study, we aim at analysing this interaction from both angles. On the one hand, we quantify the reduction of current velocity by Bolboschoenus maritimus, and on the other hand, we identify functional traits of B. maritimus’ ramets along environmental gradients. Our results show that tidal marsh vegetation is able to buffer a large proportion of the flow velocity at currents under normal conditions. Cross-shore current velocity decreased with distance from the marsh edge and was reduced by more than 50% after 15 m of vegetation. We were furthermore able to show that plants growing at the marsh edge had a significantly larger diameter than plants from inside the vegetation. We found a positive correlation between plant thickness and cross-shore current which could provide an adaptive value in habitats with high mechanical stress. With the adapted morphology of plants growing at the highly exposed marsh edge, the entire vegetation belt is able to better resist the mechanical stress of high current velocities. This self-adaptive effect thus increases the ability of B. maritimus to grow and persist in the pioneer zone and may hence better contribute to ecosystem-based coastal protection by reducing current velocity. KW - Adaptive value KW - Bolboschoenus maritimus KW - brackish marsh KW - flow velocity KW - mechanical pressure KW - morphological adaptation KW - phenotypic plasticity KW - pioneer zone Y1 - 2016 U6 - https://doi.org/10.1002/ece3.1904 SN - 2045-7758 VL - 6 SP - 1579 EP - 1589 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Tu, Rui A1 - Wang, L. A1 - Liu, Z. T1 - Real time monitoring ground motion using GPS with real time corrections JF - Survey Review N2 - The high rate GPS velocity determination technology which is based on the broadcast ephemeris and epoch differenced model can retrieve displacement of ground motion with the precision of a few centimetres to decimetres in real time. Moreover, the precision of the recovered displacement can be improved if the un-modelled errors such as broadcast ephemeris residuals, atmospheric residuals, multipath effects and high frequency noise are tackled more accurately. In this paper, we propose a method to improve the precision of the recovered displacement by appropriately making use of reference station corrections. For the reference stations, the coordinates are highly constrained to extract the error corrections that are to be broadcast via a communication link to the rover. After correcting the rover’s observations, some errors such as ephemeris residuals and atmospheric residuals are effectively eliminated or at least reduced. This improves the accuracy of the observations and thus enhances the reliability of the velocity estimation. The displacement can be recovered by integrating the estimated velocity after de-trending using a linear trend that is caused by the un-corrected residuals. The series of validation results in the experiment have shown that the displacement of the simulated motion can be real time recovered with a precision of 1–2 cm, and is thus applicable for real time monitoring of the ground motion. KW - Real time KW - High rate GPS KW - Strong motion KW - Reference station KW - Rover station Y1 - 2016 U6 - https://doi.org/10.1179/1752270614Y.0000000141 SN - 0039-6265 SN - 1752-2706 VL - 48 SP - 79 EP - 85 PB - Wiley CY - Abingdon ER - TY - JOUR A1 - Mielke, Christian A1 - Rogass, Christian A1 - Bösche, Nina Kristine A1 - Segl, Karl A1 - Altenberger, Uwe T1 - EnGeoMAP 2.0-Automated Hyperspectral Mineral Identification for the German EnMAP Space Mission JF - Remote sensing N2 - Algorithms for a rapid analysis of hyperspectral data are becoming more and more important with planned next generation spaceborne hyperspectral missions such as the Environmental Mapping and Analysis Program (EnMAP) and the Japanese Hyperspectral Imager Suite (HISUI), together with an ever growing pool of hyperspectral airborne data. The here presented EnGeoMAP 2.0 algorithm is an automated system for material characterization from imaging spectroscopy data, which builds on the theoretical framework of the Tetracorder and MICA (Material Identification and Characterization Algorithm) of the United States Geological Survey and of EnGeoMAP 1.0 from 2013. EnGeoMAP 2.0 includes automated absorption feature extraction, spatio-spectral gradient calculation and mineral anomaly detection. The usage of EnGeoMAP 2.0 is demonstrated at the mineral deposit sites of Rodalquilar (SE-Spain) and Haib River (S-Namibia) using HyMAP and simulated EnMAP data. Results from Hyperion data are presented as supplementary information. KW - EnMAP KW - Hyperion KW - EnGeoMAP 2 KW - 0 KW - mineral mapping KW - imaging spectroscopy Y1 - 2016 U6 - https://doi.org/10.3390/rs8020127 SN - 2072-4292 VL - 8 SP - 392 EP - 414 PB - MDPI CY - Basel ER - TY - JOUR A1 - Wickert, Andrew D. T1 - Open-source modular solutions for flexural isostasy: gFlex v1.0 JF - Geoscientific model development : an interactive open access journal of the European Geosciences Union N2 - Isostasy is one of the oldest and most widely applied concepts in the geosciences, but the geoscientific community lacks a coherent, easy-to-use tool to simulate flexure of a realistic (i.e., laterally heterogeneous) lithosphere under an arbitrary set of surface loads. Such a model is needed for studies of mountain building, sedimentary basin formation, glaciation, sea-level change, and other tectonic, geodynamic, and surface processes. Here I present gFlex (for GNU flexure), an open-source model that can produce analytical and finite difference solutions for lithospheric flexure in one (profile) and two (map view) dimensions. To simulate the flexural isostatic response to an imposed load, it can be used by itself or within GRASS GIS for better integration with field data. gFlex is also a component with the Community Surface Dynamics Modeling System (CSDMS) and Landlab modeling frameworks for coupling with a wide range of Earth-surface-related models, and can be coupled to additional models within Python scripts. As an example of this in-script coupling, I simulate the effects of spatially variable lithospheric thickness on a modeled Iceland ice cap. Finite difference solutions in gFlex can use any of five types of boundary conditions: 0-displacement, 0-slope (i.e., clamped); 0-slope, 0-shear; 0-moment, 0-shear (i.e., broken plate); mirror symmetry; and periodic. Typical calculations with gFlex require << 1 s to similar to 1 min on a personal laptop computer. These characteristics - multiple ways to run the model, multiple solution methods, multiple boundary conditions, and short compute time - make gFlex an effective tool for flexural isostatic modeling across the geosciences. Y1 - 2016 U6 - https://doi.org/10.5194/gmd-9-997-2016 SN - 1991-959X SN - 1991-9603 VL - 9 SP - 997 EP - 1017 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Jacobi, Stephan A1 - Heistermann, Maik T1 - Benchmarking attenuation correction procedures for six years of single-polarized C-band weather radar observations in South-West Germany JF - The quarterly journal of experimental psychology N2 - Rainfall-induced attenuation is a major source of underestimation for radar-based precipitation estimation at C-band. Unconstrained gate-by-gate correction procedures are known to be inherently unstable and thus not suited for unsupervised attenuation correction. In this study, we evaluate three different procedures to constrain gate-by-gate attenuation correction using reflectivity as the only input. These procedures are benchmarked against rainfall estimates from uncorrected radar data, using six years of radar observations from the single-polarized C-band radar in South-West Germany. The precipitation estimation error is obtained by comparing the radar-based estimates to rain gauge observations. All attenuation correction procedures benchmarked in this study lead to an effective improvement of precipitation estimation. The first method caps the corrections if the rain intensity increase exceeds a factor of two. The second method decreases the parameters of the attenuation correction iteratively for every radar beam calculation until attaining a stability criterion. The second method outperforms the first method and leads to a consistent distribution of path-integrated attenuation along the radar beam. As a third method, we propose a slight modification of Kraemer's approach which allows users to exert better control over attenuation correction by introducing an additional constraint that prevents unplausible corrections in cases of dramatic signal losses. KW - Weather radar KW - attenuation KW - quantitative precipitation estimation KW - heavy rainfall Y1 - 2016 U6 - https://doi.org/10.1080/19475705.2016.1155080 SN - 1947-5705 SN - 1947-5713 VL - 7 SP - 1785 EP - 1799 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Mueller, R. A1 - Heinicke, T. A1 - Juschus, O. A1 - Zeitz, Jutta T1 - Genesis and abiotic characteristics of three high-altitude peatlands in the Tien Shan Mountains (Kyrgyzstan), with focus on silty peatland substrates JF - Mires and peat N2 - Peatlands are scarce and threatened ecosystems in the semiarid region of Kyrgyzstan. Knowledge about the Kyrgyz peatlands is still poor and, especially, their genesis has hardly been investigated so far. Typically, the peatland substrates are characterised by the admixture of silt-sized particles in various quantities. In this work we report the abiotic properties and genesis of three peatlands within different altitudinal zones in southern Kyrgyzstan. We surveyed the stratification of the peatlands and their water chemistry. In addition, we investigated whether the silt found in the peatland substrates was deposited by wind, rivers or springs. The mineral constituents of the peatland substrates were analysed for particle size distribution and their elemental composition was compared with that of nearby loess, river and spring sediments using the immobile trace element titanium. One peatland shows a high abundance of different peatland substrates, indicating a frequent change of ecological conditions in the past. All three peatlands are fed by groundwater. Overgrazing and trampling by cattle has led to recent degradation of the upper peat layer. The resulting compaction of the peats prevents water from seeping into the substrates of the peatlands and subsequently changes their hydrology. Our results indicate that both wind and rivers have deposited silt in the peatlands, depending on their positions in the relief. Silts may also have been relocated by springs within the peatlands. KW - aeolian KW - fluvial KW - mire KW - particle size KW - X-ray fluorescence Y1 - 2016 U6 - https://doi.org/10.19189/MaP.2015.OMB.217 SN - 1819-754X VL - 18 PB - International Peat Society CY - Dundee ER - TY - JOUR A1 - Langerwisch, F. A1 - Walz, Ariane A1 - Rammig, A. A1 - Tietjen, B. A1 - Thonicke, K. A1 - Cramer, W. T1 - Climate change increases riverine carbon outgassing, while export to the ocean remains uncertain JF - Earth system dynamics N2 - Any regular interaction of land and river during flooding affects carbon pools within the terrestrial system, riverine carbon and carbon exported from the system. In the Amazon basin carbon fluxes are considerably influenced by annual flooding, during which terrigenous organic material is imported to the river. The Amazon basin therefore represents an excellent example of a tightly coupled terrestrial-riverine system. The processes of generation, conversion and transport of organic carbon in such a coupled terrigenous-riverine system strongly interact and are climate-sensitive, yet their functioning is rarely considered in Earth system models and their response to climate change is still largely unknown. To quantify regional and global carbon budgets and climate change effects on carbon pools and carbon fluxes, it is important to account for the coupling between the land, the river, the ocean and the atmosphere. We developed the RIVerine Carbon Model (RivCM), which is directly coupled to the well-established dynamic vegetation and hydrology model LPJmL, in order to account for this large-scale coupling. We evaluate RivCM with observational data and show that some of the values are reproduced quite well by the model, while we see large deviations for other variables. This is mainly caused by some simplifications we assumed. Our evaluation shows that it is possible to reproduce large-scale carbon transport across a river system but that this involves large uncertainties. Acknowledging these uncertainties, we estimate the potential changes in riverine carbon by applying RivCM for climate forcing from five climate models and three CO2 emission scenarios (Special Report on Emissions Scenarios, SRES). We find that climate change causes a doubling of riverine organic carbon in the southern and western basin while reducing it by 20% in the eastern and northern parts. In contrast, the amount of riverine inorganic carbon shows a 2- to 3-fold increase in the entire basin, independent of the SRES scenario. The export of carbon to the atmosphere increases as well, with an average of about 30 %. In contrast, changes in future export of organic carbon to the Atlantic Ocean depend on the SRES scenario and are projected to either decrease by about 8.9% (SRES A1B) or increase by about 9.1% (SRES A2). Such changes in the terrigenous-riverine system could have local and regional impacts on the carbon budget of the whole Amazon basin and parts of the Atlantic Ocean. Changes in riverine carbon could lead to a shift in the riverine nutrient supply and pH, while changes in the exported carbon to the ocean lead to changes in the supply of organic material that acts as a food source in the Atlantic. On larger scales the increased outgassing of CO2 could turn the Amazon basin from a sink of carbon to a considerable source. Therefore, we propose that the coupling of terrestrial and riverine carbon budgets should be included in subsequent analysis of the future regional carbon budget. Y1 - 2016 U6 - https://doi.org/10.5194/esd-7-559-2016 SN - 2190-4979 SN - 2190-4987 VL - 7 SP - 559 EP - 582 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Allroggen, Niklas A1 - Tronicke, Jens T1 - Attribute-based analysis of time-lapse ground-penetrating radar data JF - Geophysics N2 - Analysis of time-lapse ground-penetrating radar (GPR) data can provide information regarding subsurface hydrological processes, such as preferential flow. However, the analysis of time-lapse data is often limited by data quality; for example, for noisy input data, the interpretation of difference images is often difficult. Motivated by modern image-processing tools, we have developed two robust GPR attributes, which allow us to distinguish amplitude (contrast similarity) and time-shift (structural similarity) variations related to differences between individual time-lapse GPR data sets. We tested and evaluated our attributes using synthetic data of different complexity. Afterward, we applied them to a field data example, in which subsurface flow was induced by an artificial rainfall event. For all examples, we identified our structural similarity attribute to be a robust measure for highlighting time-lapse changes also in data with low signal-to-noise ratios. We determined that our new attribute-based workflow is a promising tool to analyze time-lapse GPR data, especially for imaging subsurface hydrological processes. Y1 - 2016 U6 - https://doi.org/10.1190/GEO2015-0171.1 SN - 0016-8033 SN - 1942-2156 VL - 81 SP - H1 EP - H8 PB - Society of Exploration Geophysicists CY - Tulsa ER - TY - JOUR A1 - Lobera, G. A1 - Batalla Villanueva, Ramon J. A1 - Vericat, D. A1 - López-Tarazón, José Andrés A1 - Tena, A. T1 - Sediment transport in two mediterranean regulated rivers JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Esera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Esera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Esera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Esera. A remarkable fact is the change of the hydrological character of the River Lem downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam. (C) 2015 Elsevier B.V. All rights reserved. KW - Suspended sediment transport KW - Sediment load KW - Flow regime KW - Barasona Reservoir KW - Siurana Reservoir KW - Ebro basin KW - Mediterranean Y1 - 2016 U6 - https://doi.org/10.1016/j.scitotenv.2015.08.018 SN - 0048-9697 SN - 1879-1026 VL - 540 SP - 101 EP - 113 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - López-Tarazón, José Andrés A1 - Lopez, Pilar A1 - Lobera, Gemma A1 - Batalla Villanueva, Ramon J. T1 - Suspended sediment, carbon and nitrogen transport in a regulated Pyrenean river JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Regulation alters the characteristics of riversty transforming parts of them into lakes, affecting their hydrology and also the physical, chemical, and biological characteristics and dynamics. Reservoirs have proven to be very effective retaining particulate materials, thereby avoiding the downstream transport of suspended sediment and the chemical substances associated with it (e.g. Carbon, C or Nitrogen, N). The study of fluvial transport of C and N is of great interest since river load represents a major link to the global C and N cycles. Moreover, reservoirs are the most important sinks for organic carbon among inland waters and have a potential significance as nitrogen sinks. In this respect, this paper investigates the effects of a Pyrenean reservoir on the runoff, suspended sediment, C and N derived from the highly active Esera and Isabena rivets. Key findings indicate that the reservoir causes a considerable impact on the Esera-Isabena river fluxes, reducing them dramatically as almost all the inputs are retained within the reservoir. Despite the very dry study year (2011-2012), it can be calculated that almost 300,000 t of suspended sediment were deposited into the Barasona Reservoir, from which more than 16,000 were C (i.e. 2200 t as organic C) and 222 t were N. These values may not be seen as remarkable in a wider global context but, assuming that around 30 hm(3) of sediment are currently stored in the reservoir, figures would increase up to ca. 2.6 x 10(6) t of C (i.e. 360,000 t of organic C) and 35,000 t of N. Nevertheless, these values are indicative and should be treated with caution as there is incomplete understanding of all the processes which affect C and N. Further investigation to establish a more complete picture of C and N yields and budgets by monitoring the different processes involved is essential. (C) 2015 Elsevier B.V. All rights reserved. KW - Suspended sediment KW - Carbon KW - Nitrogen KW - Temporal dynamics KW - Barasona Reservoir KW - River Esera KW - Ebro basin Y1 - 2016 U6 - https://doi.org/10.1016/j.scitotenv.2015.06.132 SN - 0048-9697 SN - 1879-1026 VL - 540 SP - 133 EP - 143 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lopez, Pilar A1 - López-Tarazón, José Andrés A1 - Casas-Ruiz, Joan P. A1 - Pompeo, Marcelo A1 - Ordonez, Jaime A1 - Munoz, Isabel T1 - Sediment size distribution and composition in a reservoir affected by severe water level fluctuations JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - The reservoir sediments are important sinks for organic carbon (OC), the OC burial being dependent on two opposite processes, deposition and mineralization. Hence factors such as severe water level fluctuations are expected to influence the rate of OC accumulation as they may affect both deposition and mineralization. The Barasona Reservoir has been historically threatened by siltation, whilst the use of water for irrigation involves a drastic decrease of the water level. In this context, we have studied the physical and chemical characteristics (grain size, major and minor elemental compositions, organic and inorganic carbon, and nitrogen) of the recent sediments of the Barasona Reservoir and the relationships among them in order to: a) elucidate the main processes governing OC accumulation, b) evaluate the rate of OC mineralization and c) approach the effect of drought on the sediment characteristics in this system. Our results indicated that Barasona sediments were dominated by fine silts (>60%) and clays (>20%), the mean particle size decreasing from tail to dam. Desiccation increased particle sorting and size distribution became bimodal, but no effect on average size was observed. Attending to the composition, Barasona sediments were very homogeneous with low concentrations of nitrogen (TN) and phosphorus (<12 g kg(-1) dw and <0.6 g kg(-1) dw, respectively) and high concentration of OC (approximate to 36 kg(-1) dw). TN was negatively related to dry weight Sediment mixing due to drastic changes in water level may have favoured the observed homogeneity of Barasona sediments affecting carbon, major ions and grain size. The high amount of OC deposited in Barasona sediment suggested that the adsorption of OC onto fine particles was more important than in boreal lakes. The rate of oxygen consumption by wet sediment ranged from 2.26 to 3.15 mg O-2 m(-2) day(-1), values close to those compiled for Mediterranean running waters. (C) 2015 Elsevier B.V. All rights reserved. KW - Sediment KW - Grain-size KW - Organic carbon KW - Respiration rate KW - Barasona reservoir KW - Drought Y1 - 2016 U6 - https://doi.org/10.1016/j.scitotenv.2015.06.033 SN - 0048-9697 SN - 1879-1026 VL - 540 SP - 158 EP - 167 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Florian, Norbert A1 - Lopez-Luque, Raquel A1 - Ospina-Alvarez, Natalia A1 - Hufnagel, Levente A1 - Green, Andy J. T1 - Influence of a carp invasion on the zooplankton community in Laguna Medina, a Mediterranean shallow lake JF - Limnetica N2 - The common carp (Cyprinus carpio) is a highly invasive species and an ecological engineer. It has been repeatedly shown to increase nutrient concentrations and phytoplankton biomass while destroying submerged macrophytes, although there are few studies from the Mediterranean region. We studied its impact on the zooplankton community in Laguna de Medina lake, a shallow lake in Jerez de la Frontera, south-west Spain. Carp were removed with rotenone in 2007 but returned in 2010-2011. We compared zooplankton sampled monthly from 8 points from May to December in 2008 (without carp) and 2012 (with carp). Extensive macrophyte beds present in 2008 were absent in 2012. As expected, chlorophyll-a concentrations, turbidity, total suspended solids and total phosphorus were much higher in 2012. Zooplankton richness decreased from 21 taxa in 2008 to 8 taxa in 2012, accompanied by a decrease in Shannon-Wiener diversity, an increase in Evenness and a change in size distribution with loss of larger taxa. In 2008, the crustaceans were dominated by the macrocladocerans Daphnia magna and Moina brachiata and the large calanoid copepod Arctodiaptomus salinus. In 2012, these three taxa were completely absent and the zooplankton was dominated by the alien cyclopoid Acanthocyclops americanus and the rotifers Brachionus plicatilis and Keratella quadrata. Our results confirm the disappearance of macrocladocera reported by others in mesocosm experiments with carp, and suggest that alien carp facilitate the spread of the alien copepod A. americanus. KW - Acanthocyclops KW - biomanipulation KW - Cladocera KW - invasive species KW - Mediterranean shallow lake Y1 - 2016 SN - 0213-8409 SN - 1989-1806 VL - 35 SP - 397 EP - 411 PB - Asociación Espanõla de Limnología CY - Mislata (Valencia) ER - TY - JOUR A1 - Fazeli, Mohammadreza A1 - Hinebaugh, James A1 - Fishman, Zachary A1 - Tötzke, Christian A1 - Lehnert, Werner A1 - Manke, Ingo A1 - Bazylak, Aimy T1 - Pore network modeling to explore the effects of compression on multiphase transport in polymer electrolyte membrane fuel cell gas diffusion layers JF - Journal of power sources : the international journal on the science and technology of electrochemical energy systems N2 - Understanding how compression affects the distribution of liquid water and gaseous oxygen in the polymer electrolyte membrane fuel cell gas diffusion layer (GDL) is vital for informing the design of improved porous materials for effective water management strategies. Pore networks extracted from synchrotron-based micro-computed tomography images of compressed GDLs were employed to simulate liquid water transport in GDL materials over a range of compression pressures. The oxygen transport resistance was predicted for each sample under dry and partially saturated conditions. A favorable GDL compression value for a preferred liquid water distribution and oxygen diffusion was found for Toray TGP-H-090 (10%), yet an optimum compression value was not recognized for SGL Sigracet 25BC. SGL Sigracet 25BC exhibited lower transport resistance values compared to Toray TGP-H-090, and this is attributed to the additional diffusion pathways provided by the microporous layer (MPL), an effect that is particularly significant under partially saturated conditions. (C) 2016 Elsevier B.V. All rights reserved. KW - Pore network modeling KW - Synchrotron X-ray KW - Computed tomography KW - Liquid water distribution KW - Gas diffusion layer KW - Compression Y1 - 2016 U6 - https://doi.org/10.1016/j.jpowsour.2016.10.039 SN - 0378-7753 SN - 1873-2755 VL - 335 SP - 162 EP - 171 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Cristiano, L. A1 - Meier, T. A1 - Krüger, F. A1 - Keers, H. A1 - Weidle, C. T1 - Teleseismic P-wave polarization analysis at the Grafenberg array JF - Geophysical journal international N2 - P-wave polarization at the Grafenberg array (GRF) in southern Germany is analysed in terms of azimuthal deviations and deviations in the vertical polarization using 20 yr of broad-band recordings. An automated procedure for estimating P-wave polarization parameters is suggested, based on the definition of a characteristic function, which evaluates the polarization angles and their time variability as well as the amplitude, linearity and the signal-to-noise ratio of the P wave. P-wave polarization at the GRF array is shown to depend mainly on frequency and backazimuth and only slightly on epicentral distance indicating depth-dependent local anisotropy and lateral heterogeneity. A harmonic analysis is applied to the azimuthal anomalies to analyse their periodicity as a function of backazimuth. The dominant periods are 180A degrees A and 360A degrees. At low frequencies, between 0.03 and 0.1 Hz, the observed fast directions of azimuthal anisotropy inferred from the 180A degrees A periodicity are similar across the array. The average fast direction of azimuthal anisotropy at these frequencies is N20A degrees E with an uncertainty of about 8A degrees A and is consistent with fast directions of Pn-wave propagation. Lateral velocity gradients determined for the low-frequency band are compatible with the Moho topography of the area. A more complex pattern in the horizontal fast axis orientation beneath the GRF array is observed in the high-frequency band between 0.1 and 0.5 Hz, and is attributed to anisotropy in the upper crust. A remarkable rotation of the horizontal fast axis orientation across the suture between the geological units Moldanubicum and Saxothuringicum is observed. In contrast, the 360A degrees A periodicity at high frequencies is rather consistent across the array and may either point to lower velocities in the upper crust towards the Bohemian Massif and/or to anisotropy dipping predominantly in the NE-SW direction. Altogether, P-wave polarization analysis indicates the presence of layered lithospheric anisotropy in the area of the GRF array. Seismic anisotropy is more variable in the brittle upper crust compared to lower crustal and subcrustal depths. KW - Body waves KW - Seismic anisotropy KW - Wave propagation Y1 - 2016 U6 - https://doi.org/10.1093/gji/ggw339 SN - 0956-540X SN - 1365-246X VL - 207 SP - 1456 EP - 1471 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Langer, M. A1 - Westermann, S. A1 - Boike, Julia A1 - Kirillin, G. A1 - Grosse, Guido A1 - Peng, S. A1 - Krinner, G. T1 - Rapid degradation of permafrost underneath waterbodies in tundra landscapes-Toward a representation of thermokarst in land surface models JF - Journal of geophysical research : Earth surface N2 - Waterbodies such as lakes and ponds are abundant in vast Arctic landscapes and strongly affect the thermal state of the surrounding permafrost. In order to gain a better understanding of the impact of small-and medium-sized waterbodies on permafrost and the formation of thermokarst, a land surface model was developed that can represent the vertical and lateral thermal interactions between waterbodies and permafrost. The model was validated using temperature measurements from two typical waterbodies located within the Lena River delta in northern Siberia. Impact simulations were performed under current climate conditions as well as under a moderate and a strong climate-warming scenario. The performed simulations demonstrate that small waterbodies can rise the sediment surface temperature by more than 10 degrees C and accelerate permafrost thaw by a factor of between 4 and 5. Up to 70% of this additional heat flux into the ground was found to be dissipated into the surrounding permafrost by lateral ground heat flux in the case of small, shallow, and isolated waterbodies. Under moderate climate warming, the lateral heat flux was found to reduce permafrost degradation underneath waterbodies by a factor of 2. Under stronger climatic warming, however, the lateral heat flux was too small to prevent rapid permafrost degradation. The lateral heat flux was also found to strongly impede the formation of thermokarst. Despite this stabilizing effect, our simulations have demonstrated that underneath shallow waterbodies (<1 m), thermokarst initiation happens 30 to 40 years earlier than in simulations without preexisting waterbody. Y1 - 2016 U6 - https://doi.org/10.1002/2016JF003956 SN - 2169-9003 SN - 2169-9011 VL - 121 SP - 2446 EP - 2470 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Keyser, William A1 - Tsai, Chin-Ho A1 - Iizuka, Yoshiyuki A1 - Oberhänsli, Roland A1 - Ernst, W. G. T1 - High-pressure metamorphism in the Chinshuichi area, Yuli belt, eastern Taiwan JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - Tectonic blocks and slabs of mafic-ultramafic rocks are distributed discontinuously in the Yuli metamorphic belt of Taiwan. The blocks include rare omphacite metagabbros and gamet-epidote blueschists in the Wanjung and Juisui (Tamayen) areas, respectively. Such high-pressure (HP) mineral assemblages have been attributed to a mid-Miocene subduction event. However, the surrounding psammitic, pelitic and chloritic schists are the dominant greenschist-facies lithologies of the Yuli belt. In the Chinshuichi area, tectonic blocks are enclosed in garnet-bearing metapelites, suggesting elevated pressures. In this area, we recently discovered meta-plagiogranite containing the assemblage glaucophane + omphacite (X-Jd up to 039) + rutile + quartz, indicating P-T conditions near 13 kbar/550 degrees C. New equilibrium phase modeling of a garnet-paragonite mica schist and compositional isopleths for peak assemblage minerals garnet and phengite (Si = 3.33-3.37 pfu) indicate metamorphic conditions of 15.5-17 kbar/530-550 degrees C. These P-T estimates are higher than previously reported in the Yuli belt and suggest that both tectonic blocks and host metapelites underwent HP metamorphism. The juxtaposition of tectonic blocks and metapelites apparently occurred during the formation of a subduction-accretionary complex, followed by exhumation facilitated by a collisional event. These new findings imply that HP metamorphism was not limited to tectonic blocks, and instead played a significant role attending orogenesis in eastern Taiwan. (C) 2015 Elsevier B.V. All rights reserved. KW - Equilibrium phase modeling KW - Omphacite KW - Glaucophane KW - Meta-plagiogranite KW - High-pressure metamorphism KW - Yuli belt KW - Tananao Complex Y1 - 2016 U6 - https://doi.org/10.1016/j.tecto.2015.09.012 SN - 0040-1951 SN - 1879-3266 VL - 692 SP - 191 EP - 202 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Fritz, Joerg A1 - Tagle, Roald A1 - Ashworth, Luisa A1 - Schmitt, Ralf Thomas A1 - Hofmann, Axel A1 - Luais, Beatrice A1 - Harris, Phillip D. A1 - Hoehnel, Desiree A1 - Özdemir, Seda A1 - Mohr-Westheide, Tanja A1 - Koeberl, Christian T1 - Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land, South Africa JF - Quaestiones geographicae N2 - A Paleoarchean impact spherule-bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro-X-ray fluorescence (lXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer-scale, assisted in the localization and characterization of eight spherule-bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The lXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni-Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3-rich and can be distinguished from the Al2O3-poor marine sediments by distinct Al-OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al-OH-rich spherule layers in Al2O3-poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism. Y1 - 2016 U6 - https://doi.org/10.1111/maps.12736 SN - 1086-9379 SN - 1945-5100 VL - 51 SP - 2441 EP - 2458 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Wang, Hao A1 - Wang, Xue-jiang A1 - Wang, Wei-shi A1 - Yan, Xiang-bo A1 - Xia, Peng A1 - Chen, Jie A1 - Zhao, Jian-fu T1 - Modeling and optimization of struvite recovery from wastewater and reusing for heavy metals immobilization in contaminated soil JF - Journal of chemical technology & biotechnology N2 - BACKROUND: Few studies have been carried out to connect nutrients recovery from wastewater and heavy metals immobilization in contaminated soil. To achieve the goal, ammonia nitrogen (AN) and phosphorus (P) were recovered from rare-earth wastewater by using the formation of struvite, which was used as the amendment with plant ash for copper, lead and chromium immobilization. RESULTS: AN removal efficiency and residual P reached 95.32 +/- 0.73% and 6.14 +/- 1.72mgL(-1) under optimal conditions: pH= 9.0, n(Mg): n(N): n(P)= 1.2: 1: 1.1, which were obtained using response surface methodology (RSM). The minimum available concentrations of Cu, Pb and Cr (CPC) separately reduced to 320.82 mg kg(-1), 190.77 mg kg(-1) and 121.46 mg kg(-1) with increasing immobilization time at the mass ratio of phosphate precipitate (PP)/plant ash (PA) of 1: 3. Humic acid (HA) and fulvic acid (FA) were beneficial to immobilize Cu, both of which showed no effect or even a negative effect on Pb and Cr immobilization. KW - precipitation KW - experimental design KW - immobilization KW - heavy metals KW - environmental remediation Y1 - 2016 U6 - https://doi.org/10.1002/jctb.4931 SN - 0268-2575 SN - 1097-4660 VL - 91 SP - 3045 EP - 3052 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Wanner, Manfred A1 - Seidl-Lampa, Barbara A1 - Höhn, Axel A1 - Puppe, Daniel A1 - Meisterfeld, Ralf A1 - Sommer, Michael T1 - Culture growth of testate amoebae under different silicon concentrations JF - European journal of protistology N2 - Testate amoebae with self-secreted siliceous shell platelets ("idiosomes") play an important role in terrestrial silicon (Si) cycles. In this context, Si-dependent culture growth dynamics of idiosomic testate amoebae are of interest. Clonal cultures of idiosomic testate amoebae were analyzed under three different Si concentrations: low (50 mu mol L-1), moderate/site-specific (150 mu mol L-1) and high Si supply (500 mu mol L-1). Food (Saccharomyces cerevisiae) was provided in surplus. (i) Shell size of four different clones of idiosomic testate amoebae either decreased (Trinema galeata, Euglypha filifera cf.), increased (E. rotunda cf.), or did not change (E. rotunda) under the lowest Si concentration (50 mu mol Si L-1). (ii) Culture growth of idiosomic Euglypha rotunda was dependent on Si concentration. The more Si available in the culture medium, the earlier the entry into exponential growth phase. (iii) Culture growth of idiosomic Euglypha rotunda was dependent on origin of inoculum. Amoebae previously cultured under a moderate Si concentration revealed highest sustainability in consecutive cultures. Amoebae derived from cultures with high Si concentrations showed rapid culture growth which finished early in consecutive cultures. (iv) Si (diluted in the culture medium) was absorbed by amoebae and fixed in the amoeba shells resulting in decreased Si concentrations. (C) 2016 Elsevier GmbH. All rights reserved. KW - Amoebal silicon KW - Sommer et al. 2006 KW - Biosilicification KW - Consumption KW - Culture growth dynamics KW - Euglyphida KW - Terrestrial Si cycle Y1 - 2016 U6 - https://doi.org/10.1016/j.ejop.2016.08.008 SN - 0932-4739 SN - 1618-0429 VL - 56 SP - 171 EP - 179 PB - Royal Society of Chemistry CY - Jena ER - TY - JOUR A1 - Engels, Stefan A1 - Brauer, Achim A1 - Buddelmeijer, Nico A1 - Martin-Puertas, Celia A1 - Rach, Oliver A1 - Sachse, Dirk A1 - Van Geel, Bas T1 - Subdecadal-scale vegetation responses to a previously unknown late-Allerod climate fluctuation and Younger Dryas cooling at Lake Meerfelder Maar (Germany) JF - Journal of quaternary science N2 - Lake Meerfelder Maar (MFM) is the northernmost Western European sediment record with annual laminations across the Younger Dryas (YD), and the onset of the YD in the record of MFM has previously been defined as an increase in non-arboreal pollen abundance at ca. 12 680 varve a BP. Here we present a palynological record at unprecedented subdecadal resolution for MFM, covering the Allerod-YD transition. Our results show a fluctuation in pollen accumulation rates (PARs) before the onset of the YD, with lower rates between ca. 12 725 and 12 685 varve a BP. The fluctuation in PARs occurs simultaneous with a previously undescribed short fluctuation in sediment composition and varve thickness, as well as with changes in biogeochemical proxies. The combined evidence indicates signs of climatic instability ca. 45 years before the onset of the YD. The PAR records of Betula and Pinus furthermore show earlier and more abrupt changes at the onset of the YD than the percentage-records do. Finally, heliophilous herbaceous taxa show a delayed increase following the onset of the YD of ca. 145 years. This paper illustrates the potential to identify previously unrecognized climate variability and vegetation change when using subdecadal-resolution analyses. Copyright (C) 2016 John Wiley & Sons, Ltd. KW - climate instability KW - Lateglacial KW - Meerfelder Maar KW - pollen accumulation rates KW - vegetation change Y1 - 2016 U6 - https://doi.org/10.1002/jqs.2900 SN - 0267-8179 SN - 1099-1417 VL - 31 SP - 741 EP - 752 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Qiu, C. A1 - Krüger, Y. A1 - Wilke, Max A1 - Marti, D. A1 - Ricka, J. A1 - Frenz, M. T1 - Exploration of the phase diagram of liquid water in the low-temperature metastable region using synthetic fluid inclusions JF - Physical chemistry, chemical physics : a journal of European Chemical Societies N2 - We present new experimental data of the low-temperature metastable region of liquid water derived from high-density synthetic fluid inclusions (996-916 kg m(-3)) in quartz. Microthermometric measurements include: (i) prograde (upon heating) and retrograde (upon cooling) liquid-vapour homogenisation. We used single ultrashort laser pulses to stimulate vapour bubble nucleation in initially monophase liquid inclusions. Water densities were calculated based on prograde homogenisation temperatures using the IAPWS-95 formulation. We found retrograde liquid-vapour homogenisation temperatures in excellent agreement with IAPWS-95. (ii) Retrograde ice nucleation. Raman spectroscopy was used to determine the nucleation of ice in the absence of the vapour bubble. Our ice nucleation data in the doubly metastable region are inconsistent with the low-temperature trend of the spinodal predicted by IAPWS-95, as liquid water with a density of 921 kg m(-3) remains in a homogeneous state during cooling down to a temperature of -30.5 degrees C, where it is transformed into ice whose density corresponds to zero pressure. (iii) Ice melting. Ice melting temperatures of up to 6.8 degrees C were measured in the absence of the vapour bubble, i.e. in the negative pressure region. (iv) Spontaneous retrograde and, for the first time, prograde vapour bubble nucleation. Prograde bubble nucleation occurred upon heating at temperatures above ice melting. The occurrence of prograde and retrograde vapour bubble nucleation in the same inclusions indicates a maximum of the bubble nucleation curve in the R-T plane at around 40 degrees C. The new experimental data represent valuable benchmarks to evaluate and further improve theoretical models describing the p-V-T properties of metastable water in the low-temperature region. Y1 - 2016 U6 - https://doi.org/10.1039/c6cp04250c SN - 1463-9076 SN - 1463-9084 VL - 18 SP - 28227 EP - 28241 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Kruse, Stefan A1 - Wieczorek, Mareike A1 - Jeltsch, Florian A1 - Herzschuh, Ulrike T1 - Treeline dynamics in Siberia under changing climates as inferred from an individual-based model for Larix JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog KW - Forest change KW - IBM KW - ODD model description KW - Larix gmelinii KW - Permafrost ecosystem KW - Time-lag effects Y1 - 2016 U6 - https://doi.org/10.1016/j.ecolmodel.2016.08.003 SN - 0304-3800 SN - 1872-7026 VL - 338 SP - 101 EP - 121 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Siegmund, Jonatan F. A1 - Wiedermann, Marc A1 - Donges, Jonathan Friedemann A1 - Donner, Reik Volker T1 - Impact of temperature and precipitation extremes on the flowering dates of four German wildlife shrub species JF - Biogeosciences N2 - Ongoing climate change is known to cause an increase in the frequency and amplitude of local temperature and precipitation extremes in many regions of the Earth. While gradual changes in the climatological conditions have already been shown to strongly influence plant flowering dates, the question arises if and how extremes specifically impact the timing of this important phenological phase. Studying this question calls for the application of statistical methods that are tailored to the specific properties of event time series. Here, we employ event coincidence analysis, a novel statistical tool that allows assessing whether or not two types of events exhibit similar sequences of occurrences in order to systematically quantify simultaneities between meteorological extremes and the timing of the flowering of four shrub species across Germany. Our study confirms previous findings of experimental studies by highlighting the impact of early spring temperatures on the flowering of the investigated plants. However, previous studies solely based on correlation analysis do not allow deriving explicit estimates of the strength of such interdependencies without further assumptions, a gap that is closed by our analysis. In addition to direct impacts of extremely warm and cold spring temperatures, our analysis reveals statistically significant indications of an influence of temperature extremes in the autumn preceding the flowering. Y1 - 2016 U6 - https://doi.org/10.5194/bg-13-5541-2016 SN - 1726-4170 SN - 1726-4189 VL - 13 SP - 5541 EP - 5555 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Gamarra, B. A1 - Sachse, Dirk A1 - Kahmen, A. T1 - Effects of leaf water evaporative H-2-enrichment and biosynthetic fractionation on leaf wax n-alkane H-2 values in C3 and C4 grasses JF - Plant, cell & environment : cell physiology, whole-plant physiology, community physiology N2 - Leaf wax n-alkane H-2 values carry important information about environmental and ecophysiological processes in plants. However, the physiological and biochemical drivers that shape leaf wax n-alkane H-2 values are not completely understood. It is particularly unclear why n-alkanes in grasses are typically H-2-depleted compared with plants from other taxonomic groups such as dicotyledonous plants and why C3 grasses are H-2-depleted compared with C4 grasses. To resolve these uncertainties, we quantified the effects of leaf water evaporative H-2-enrichment and biosynthetic hydrogen isotope fractionation on n-alkane H-2 values for a range of C3 and C4 grasses grown in climate-controlled chambers. We found that only a fraction of leaf water evaporative H-2-enrichment is imprinted on the leaf wax n-alkane H-2 values in grasses. This is interesting, as previous studies have shown in dicotyledonous plants a nearly complete transfer of this H-2-enrichment to the n-alkane H-2 values. We thus infer that the typically observed H-2-depletion of n-alkanes in grasses (as opposed to dicots) is because only a fraction of the leaf water evaporative H-2-enrichment is imprinted on the H-2 values. Our experiments also show that differences in n-alkane H-2 values between C3 and C4 grasses are largely the result of systematic differences in biosynthetic fractionation between these two plant groups, which was on average -198 and-159 parts per thousand for C3 and C4 grasses, respectively. We present novel and exciting data on how leaf wax n-alkane 2H values from grasses are affected by plant physiological (leaf water evaporative 2H-enrichment) or biochemical processes (biosynthetic hydrogen isotope fractionation). These results are very interesting because they shed new light on how naturally observed differences between 2H values from C3 and C4 grasses and dicots can be explained by systematic differences in the biosynthesis of n-alkanes between these plant group (i.e. largely driven by NADPH origins). KW - biosynthetic fractionation KW - C3 and C4 grasses KW - deuterium KW - leaf water evaporative H-2-enrichment KW - leaf wax n-alkanes Y1 - 2016 U6 - https://doi.org/10.1111/pce.12789 SN - 0140-7791 SN - 1365-3040 VL - 39 SP - 2390 EP - 2403 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Voss, Sebastian A1 - Zimmermann, Beate A1 - Zimmermann, Alexander T1 - Detecting spatial structures in throughfall data: The effect of extent, sample size, sampling design, and variogram estimation method JF - Journal of hydrology N2 - In the last decades, an increasing number of studies analyzed spatial patterns in throughfall by means of variograms. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and a layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation method on variogram estimation of throughfall data. For our investigation, we first generated non Gaussian random fields based on throughfall data with large outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling) and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments (non-robust and robust estimators) and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the number recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous through fall studies relied on method-of-moments variogram estimation and sample sizes <<200, currently available data are prone to large uncertainties. (C) 2016 Elsevier B.V. All rights reserved. KW - Throughfall KW - Geostatistics KW - Sampling KW - variogram KW - Residual maximum likelihood Y1 - 2016 U6 - https://doi.org/10.1016/j.jhydrol.2016.06.042 SN - 0022-1694 SN - 1879-2707 VL - 540 SP - 527 EP - 537 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rehman, Hafiz Ur A1 - Lee, Hao-Yang A1 - Chung, Sun-Lin A1 - Khan, Tahseenullah A1 - Yamamoto, Hiroshi O´Brien T1 - Source and mode of the Permian Panjal Trap magmatism: Evidence from zircon U-Pb and Hf isotopes and trace element data from the Himalayan ultrahigh-pressure rocks JF - Lithos : an international journal of mineralogy, petrology, and geochemistry N2 - We present an integrated study of LA-ICP-MS U-Pb age, Hf isotopes, and trace element geochemistry of zircons from the Himalayan eclogites (mafic rocks) and their host gneisses (felsic rocks) from the Kaghan Valley in Pakistan in order to understand the source and mode of their magmatic protoliths and the effect of metamorphism. Zircons from the so-called Group I (high-pressure) eclogites yielded U-Pb mean ages of 259 +/- 10 Ma (MSWD = 0.74), whereas those of Group II (ultrahigh-pressure) eclogites yielded 48 3 Ma (MSWD = 0.71). In felsic gneisses the central or core domains of zircons yielded ages similar to those from Group I edogites but zircon overgrowth domains yielded 47 +/- 1 Ma (MSWD = 1.9). Trace element data suggest a magmatic origin for Group I-derived (having Th/U ratios: >0.5) and metamorphic origin for Group II -derived (Th/U < 0.07) zircons, respectively. Zircon Hf isotope data, obtained from the same dated spots, show positive initial Hf-176/Hf-177 isotopic ratios referred to as "epsilon(Hf)(t)" of around +10 in Group I eclogites; +7 in Group II eclogites; and +8 in felsic gneisses zircons, respectively, thus indicate a juvenile mantle source for the protolith rocks (Panjal Traps) with almost no contribution from the ancient crustal material. The similar epsilon(Hf)(t) values, identical protolith ages and trace element compositions of zircons in felsic (granites or rhyolites) and mafic (basalt and dolerite) rocks attest to a bimodal magmatism accounting for the Panjal Traps during the Permian. Later, during India-Asia collision in Eocene times, both the felsic and mafic lithologies were subducted to mantle-depths (>90 km; coesite-stable) and experienced ultrahigh-pressure metamorphism before their final exhumation. (C) 2016 Elsevier B.V. All rights reserved. KW - Himalaya KW - Panjal Traps KW - UHP edogites and felsic gneisses KW - Zircon U-Pb age KW - Hf isotopes KW - Trace element geochemistry Y1 - 2016 U6 - https://doi.org/10.1016/j.lithos.2016.06.001 SN - 0024-4937 SN - 1872-6143 VL - 260 SP - 286 EP - 299 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Stroeven, Arjen P. A1 - Hättestrand, Clas A1 - Kleman, Johan A1 - Heyman, Jakob A1 - Fabel, Derek A1 - Fredin, Ola A1 - Goodfellow, Bradley W. A1 - Harbor, Jonathan M. A1 - Jansen, John D. A1 - Olsen, Lars A1 - Caffee, Marc W. A1 - Fink, David A1 - Lundqvist, Jan A1 - Rosqvist, Gunhild C. A1 - Stromberg, Bo A1 - Jansson, Krister N. T1 - Deglaciation of Fennoscandia JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - To provide a new reconstruction of the deglaciation of the Fennoscandian Ice Sheet, in the form of calendar-year time-slices, which are particularly useful for ice sheet modelling, we have compiled and synthesized published geomorphological data for eskers, ice-marginal formations, lineations, marginal meltwater channels, striae, ice-dammed lakes, and geochronological data from radiocarbon, varve, optically-stimulated luminescence, and cosmogenic nuclide dating. This is summarized as a deglaciation map of the Fennoscandian Ice Sheet with isochrons marking every 1000 years between 22 and 13 cal kyr BP and every hundred years between 11.6 and final ice decay after 9.7 cal kyr BP. Deglaciation patterns vary across the Fennoscandian Ice Sheet domain, reflecting differences in climatic and geomorphic settings as well as ice sheet basal thermal conditions and terrestrial versus marine margins. For example, the ice sheet margin in the high-precipitation coastal setting of the western sector responded sensitively to climatic variations leaving a detailed record of prominent moraines and other ice-marginal deposits in many fjords and coastal valleys. Retreat rates across the southern sector differed between slow retreat of the terrestrial margin in western and southern Sweden and rapid retreat of the calving ice margin in the Baltic Basin. Our reconstruction is consistent with much of the published research. However, the synthesis of a large amount of existing and new data support refined reconstructions in some areas. For example, the LGM extent of the ice sheet in northwestern Russia was located far east and it occurred at a later time than the rest of the ice sheet, at around 17-15 cal kyr BP. We also propose a slightly different chronology of moraine formation over southern Sweden based on improved correlations of moraine segments using new LiDAR data and tying the timing of moraine formation to Greenland ice core cold stages. Retreat rates vary by as much as an order of magnitude in different sectors of the ice sheet, with the lowest rates on the high-elevation and maritime Norwegian margin. Retreat rates compared to the climatic information provided by the Greenland ice core record show a general correspondence between retreat rate and climatic forcing, although a close match between retreat rate and climate is unlikely because of other controls, such as topography and marine versus terrestrial margins. Overall, the time slice reconstructions of Fennoscandian Ice Sheet deglaciation from 22 to 9.7 cal kyr BP provide an important dataset for understanding the contexts that underpin spatial and temporal patterns in retreat of the Fennoscandian Ice Sheet, and are an important resource for testing and refining ice sheet models. (C) 2015 The Authors. Published by Elsevier Ltd. KW - Fennoscandian Ice Sheet KW - Deglaciation KW - Glacial geomorphology KW - Geochronology KW - Ice sheet dynamics Y1 - 2016 U6 - https://doi.org/10.1016/j.quascirev.2015.09.016 SN - 0277-3791 VL - 147 SP - 91 EP - 121 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Puppe, Daniel A1 - Höhn, Axel A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Sommer, Michael T1 - As time goes by-Spatiotemporal changes of biogenic Si pools in initial soils of an artificial catchment in NE Germany JF - Applied soil ecology : a section of agriculture, ecosystems & environment KW - Biogenic silica KW - Diatom frustule KW - Testate amoeba shell KW - Sponge spicule KW - Initial ecosystem Y1 - 2016 U6 - https://doi.org/10.1016/j.apsoil.2016.01.020 SN - 0929-1393 SN - 1873-0272 VL - 105 SP - 9 EP - 16 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Malinowski, Radostaw A1 - Höfle, Bernhard A1 - Koenig, Kristina A1 - Groom, Geoff A1 - Schwanghart, Wolfgang A1 - Heckrath, Goswin T1 - Local-scale flood mapping on vegetated floodplains from radiometrically calibrated airborne LiDAR data JF - ISPRS journal of photogrammetry and remote sensing : official publication of the International Society for Photogrammetry and Remote Sensing N2 - Knowledge about the magnitude of localised flooding of riverine areas is crucial for appropriate land management and administration at regional and local levels. However, detection and delineation of localised flooding with remote sensing techniques are often hampered on floodplains by the presence of herbaceous vegetation. To address this problem, this study presents the application of full waveform airborne laser scanning (ALS) data for detection of floodwater extent. In general, water surfaces are characterised by low values of backscattered energy due to water absorption of the infrared laser shots, but the exact strength of the recorded laser pulse depends on the area covered by the targets located within a laser pulse footprint area. To account for this we analysed the physical quantity of radio metrically calibrated ALS data, the backscattering coefficient, in relation to water and vegetation coverage within a single laser footprint. The results showed that the backscatter was negatively correlated to water coverage, and that of the three distinguished classes of water coverage (low, medium, and high) only the class with the largest extent of water cover (>70%) had relatively distinct characteristics that can be used for classification of water surfaces. Following the laser footprint analysis, three classifiers, namely AdaBoost with Decision Tree, Naive Bayes and Random Forest, were utilised to classify laser points into flooded and non-flooded classes and to derive the map of flooding extent. The performance of the classifiers is highly dependent on the set of laser points features used. Best performance was achieved by combining radiometric and geometric laser point features. The accuracy of flooding maps based solely on radiometric features resulted in overall accuracies of up to 70% and was limited due to the overlap of the backscattering coefficient values between water and other land cover classes. Our point-based classification methods assure a high mapping accuracy (similar to 89%) and demonstrate the potential of using full-waveform ALS data to detect water surfaces on floodplain areas with limited water surface exposition through the vegetation canopy. (C) 2016 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved. KW - ALS KW - LiDAR KW - Point cloud KW - Inundation KW - Full-waveform KW - Water Y1 - 2016 U6 - https://doi.org/10.1016/j.isprsjprs.2016.06.009 SN - 0924-2716 SN - 1872-8235 VL - 119 SP - 267 EP - 279 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Agarwal, Ankit A1 - Maheswaran, Rathinasamy A1 - Kurths, Jürgen A1 - Khosa, R. T1 - Wavelet Spectrum and Self-Organizing Maps-Based Approach for Hydrologic Regionalization -a Case Study in the Western United States JF - Water Resources Management N2 - Hydrologic regionalization deals with the investigation of homogeneity in watersheds and provides a classification of watersheds for regional analysis. The classification thus obtained can be used as a basis for mapping data from gauged to ungauged sites and can improve extreme event prediction. This paper proposes a wavelet power spectrum (WPS) coupled with the self-organizing map method for clustering hydrologic catchments. The application of this technique is implemented for gauged catchments. As a test case study, monthly streamflow records observed at 117 selected catchments throughout the western United States from 1951 through 2002. Further, based on WPS of each station, catchments are classified into homogeneous clusters, which provides a representative WPS pattern for the streamflow stations in each cluster. KW - Wavelet power spectrum KW - Regionalization KW - Ungauged catchments KW - K-means technique KW - Self-organizing map Y1 - 2016 U6 - https://doi.org/10.1007/s11269-016-1428-1 SN - 0920-4741 SN - 1573-1650 VL - 30 SP - 4399 EP - 4413 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Noury, M. A1 - Bernet, M. A1 - Schildgen, Taylor F. A1 - Simon-Labric, T. A1 - Philippon, M. A1 - Sempere, T. T1 - Crustal-scale block tilting during Andean trench-parallel extension: Structural and geo-thermochronological insights JF - Tectonics N2 - Despite a long history of plate convergence at the western margin of the South American plate that has been ongoing since at least the Early Paleozoic, the southern Peruvian fore-arc displays little to no evidence of shortening. In the light of this observation, we assess the deformation history of the southern Peruvian fore-arc and its geodynamic implications. To accomplish this, we present a new structural and geo-thermochronological data set (zircon U-Pb, mica Ar-40/Ar-39, apatite and zircon fission-track and zircon (U-Th)/He analyses) for samples collected along a 400km long transect parallel to the trench. Our results show that the Mesoproterozoic gneissic basement was mainly at temperatures 350 degrees C since the Neoproterozoic and was later intruded by Jurassic volcanic arc plutons. Along the coast, a peculiar apatite fission-track age pattern, coupled with field observations and a synthesis of available geological maps, allows us to identify crustal-scale tilted blocks that span the coastal Peruvian fore-arc. These blocks, bounded by normal faults that are orthogonal to the trench, suggest post-60Ma trench-parallel extension that potentially accommodated oroclinal bending in this region. Block tilting is consistent with the observed and previously described switch in the location of sedimentary sources in the fore-arc basin. Our data set allows us to estimate the cumulative slip on these faults to be less than 2km and questions the large amount of trench-parallel extension suggested to have accommodated this bending. KW - Central Andes KW - Peruvian fore arc KW - thermochronology KW - trench-parallel extension KW - oroclinal bending Y1 - 2016 U6 - https://doi.org/10.1002/2016TC004231 SN - 0278-7407 SN - 1944-9194 VL - 35 SP - 2052 EP - 2069 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Di Capua, Giorgia A1 - Coumou, Dim T1 - Changes in meandering of the Northern Hemisphere circulation JF - Environmental research letters N2 - Strong waves in the mid-latitude circulation have been linked to extreme surface weather and thus changes in waviness could have serious consequences for society. Several theories have been proposed which could alter waviness, including tropical sea surface temperature anomalies or rapid climate change in the Arctic. However, so far it remains unclear whether any changes in waviness have actually occurred. Here we propose a novel meandering index which captures the maximum waviness in geopotential height contours at any given day, using all information of the full spatial position of each contour. Data are analysed on different time scale (from daily to 11 day running means) and both on hemispheric and regional scales. Using quantile regressions, we analyse how seasonal distributions of this index have changed over 1979-2015. The most robust changes are detected for autumn which has seen a pronounced increase in strongly meandering patterns at the hemispheric level as well as over the Eurasian sector. In summer for both the hemisphere and the Eurasian sector, significant downward trends in meandering are detected on daily timescales which is consistent with the recently reported decrease in summer storm track activity. The American sector shows the strongest increase in meandering in the warm season: in particular for 11 day running mean data, indicating enhanced amplitudes of quasi-stationary waves. Our findings have implications for both the occurrence of recent cold spells and persistent heat waves in the mid-latitudes. KW - Rossby waves KW - climate change KW - extreme events KW - mid-latitudes flow Y1 - 2016 U6 - https://doi.org/10.1088/1748-9326/11/9/094028 SN - 1748-9326 VL - 11 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Wang, Xinxin A1 - Huang, Xianyu A1 - Sachse, Dirk A1 - Ding, Weihua A1 - Xue, Jiantao T1 - Molecular Paleoclimate Reconstructions over the Last 9 ka from a Peat Sequence in South China JF - PLoS one N2 - To achieve a better understanding of Holocene climate change in the monsoon regions of China, we investigated the molecular distributions and carbon and hydrogen isotope compositions delta C-13 and delta D values) of long-chain n-alkanes in a peat core from the Shiwangutian SWGT) peatland, south China over the last 9 ka. By comparisons with other climate records, we found that the delta C-13 values of the long-chain n-alkanes can be a proxy for humidity, while the dD values of the long-chain n-alkanes primarily recorded the moisture source dD signal during 9-1.8 ka BP and responded to the dry climate during 1.8-0.3 ka BP. Together with the average chain length ACL) and the carbon preference index CPI) data, the climate evolution over last 9 ka in the SWGT peatland can be divided into three stages. During the first stage 9-5 ka BP), the delta C-13 values were depleted and CPI and Paq values were low, while ACL values were high. They reveal a period of warm and wet climate, which is regarded as the Holocene optimum. The second stage 5-1.8 ka BP) witnessed a shift to relatively cool and dry climate, as indicated by the more positive delta C-13 values and lower ACL values. During the third stage 1.8-0.3 ka BP), the delta C-13, delta D, CPI and Paq values showed marked increase and ACL values varied greatly, implying an abrupt change to cold and dry conditions. This climate pattern corresponds to the broad decline in Asian monsoon intensity through the latter part of the Holocene. Our results do not support a later Holocene optimum in south China as suggested by previous studies. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0160934 SN - 1932-6203 VL - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Sternemann, C. A1 - Wilke, Max T1 - Spectroscopy of low and intermediate Z elements at extreme conditions: in situ studies of Earth materials at pressure and temperature via X-ray Raman scattering JF - High pressure research N2 - X-ray Raman scattering spectroscopy is an emerging method in the study of low and intermediate Z elements' core-electron excitations at extreme conditions in order to reveal information on local structure and electronic state of matter in situ. We discuss the capabilities of this method to address questions in Earth materials' science and demonstrate its sensitivity to detect changes in the oxidation state, electronic structure, coordination, and spin state. Examples are presented for the study of the oxygen K-, silicon L- and iron M-edges. We assess the application of both temperature and pressure in such investigations exploiting diamond anvil cells in combination with resistive or laser heating which is required to achieve realistic conditions of the Earth's crust, mantle, and core. KW - X-ray Raman scattering KW - inelastic X-ray scattering KW - X-ray absorption KW - high pressure research KW - diamond anvil cell KW - minerals KW - glasses KW - melts KW - Earth materials KW - spin transition KW - bonding transition KW - coordination transformation KW - oxidation state KW - electronic structure Y1 - 2016 U6 - https://doi.org/10.1080/08957959.2016.1198903 SN - 0895-7959 SN - 1477-2299 VL - 36 SP - 275 EP - 292 PB - IOP Publ. Ltd. CY - Abingdon ER - TY - JOUR A1 - Rosa, A. D. A1 - Pohlenz, Julia A1 - de Grouchy, C. A1 - Cochain, B. A1 - Kono, Y. A1 - Pasternak, S. A1 - Mathon, O. A1 - Irifune, T. A1 - Wilke, Max T1 - In situ characterization of liquid network structures at high pressure and temperature using X-ray absorption spectroscopy coupled with the Paris-Edinburgh press JF - High pressure research N2 - We review recent progress in studying structural properties of liquids using X-ray absorption spectroscopy coupled with the Paris-Edinburgh press at third-generation synchrotron facilities. This experimental method allows for detecting subtle changes in atomic arrangements of melts over a wide pressure-temperature range. It has been also employed to monitor variations of the local coordination environment of diluted species contained in glasses, liquids and crystalline phases as a function of the pressure and temperature. Such information is of great importance for gaining deeper insights into the physico-chemical properties of liquids at extreme condition, including the understanding of such phenomena as liquid-liquid phase transitions, viscosity drops and various transport properties of geological melts. Here, we describe the experimental approach and discuss its potential in structural characterization on selected scientific highlights. Finally, the current ongoing instrumental developments and future scientific opportunities are discussed. KW - X-ray absorption KW - Paris-Edinburgh press KW - liquid structure KW - high pressure and temperature KW - EXAFS Y1 - 2016 U6 - https://doi.org/10.1080/08957959.2016.1199693 SN - 0895-7959 SN - 1477-2299 VL - 36 SP - 332 EP - 347 PB - American Geophysical Union CY - Abingdon ER - TY - JOUR A1 - Githui, Faith A1 - Thayalakumaran, Thabo A1 - Selle, Benny T1 - Estimating irrigation inputs for distributed hydrological modelling: a case study from an irrigated catchment in southeast Australia JF - Hydrological processes N2 - Adequate irrigation inputs are essential for the application of hydrological models in irrigated catchments, but reliable data on both the amount and the frequency of irrigation applications are often missing at an appropriate spatial scale. In this paper, we demonstrate and test approaches to estimate irrigation inputs for distributed hydrological modelling. In this context, the Soil and Water Assessment Tool was applied to simulate water balances for an irrigated catchment in southeast Australia during the period 2008–2010. Two methods for estimating irrigation inputs were tested. One method was based on a fixed irrigation application rate, whereas the other one had variable irrigation rates depending on season and the irrigated crop. These two approaches were also compared with the ‘auto-irrigation’ method within the Soil and Water Assessment Tool model. The method with variable irrigation rates resulted in the most reasonable interpretation of the readily available irrigation data, consistent estimates of irrigation runoff coefficients throughout the year and the best fit to observed data on both drain flows at the catchment outlet and spatial evapotranspiration patterns. We also found that the different irrigation inputs significantly affected simulated water balances, in particular deep percolation under relatively dry climatic conditions. All these results suggest that it is possible to infer irrigation inputs from readily available data and local knowledge, adequate for hydrological modelling in irrigated catchments. Our study also demonstrates that, in order to predict reliable water balances in irrigated catchments, an accurate knowledge of irrigation scheduling and irrigation runoff is required. Copyright © 2015 John Wiley & Sons, Ltd. KW - SWAT KW - irrigation runoff KW - remotely sensed evapotranspiration Y1 - 2016 U6 - https://doi.org/10.1002/hyp.10757 SN - 0885-6087 SN - 1099-1085 VL - 30 SP - 1824 EP - 1835 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Quirico, E. A1 - Moroz, Liubov V. A1 - Schmitt, B. A1 - Arnold, Gabriele A1 - Faure, M. A1 - Beck, P. A1 - Bonal, L. A1 - Ciarniello, M. A1 - Capaccioni, F. A1 - Filacchione, G. A1 - Erard, S. A1 - Leyrat, C. A1 - Bockelee-Morvan, D. A1 - Zinzi, A. A1 - Palomba, E. A1 - Drossart, P. A1 - Tosi, F. A1 - Capria, M. T. A1 - De Sanctis, M. C. A1 - Raponi, A. A1 - Fonti, S. A1 - Mancarella, F. A1 - Orofino, V. A1 - Barucci, A. A1 - Blecka, M. I. A1 - Carlson, R. A1 - Despan, D. A1 - Faure, A. A1 - Fornasier, S. A1 - Gudipati, M. S. A1 - Longobardo, A. A1 - Markus, K. A1 - Mennella, V. A1 - Merlin, F. A1 - Piccioni, G. A1 - Rousseau, B. A1 - Taylor, F. T1 - Refractory and semi-volatile organics at the surface of comet 67P/Churyumov-Gerasimenko: Insights from the VIRTIS/Rosetta imaging spectrometer JF - Icarus : international journal of solar system studies N2 - The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument aboard the Rosetta spacecraft has performed extensive spectral mapping of the surface of comet 67P/Churyumov-Gerasimenko in the range 0.3-5 mu m. The reflectance spectra collected across the surface display a low reflectance factor over the whole spectral range, two spectral slopes in the visible and near-infrared ranges and a broad absorption band centered at 3.2 mu m. The first two of these characteristics are typical of dark small bodies of the Solar System and are difficult to interpret in terms of composition. Moreover, solar wind irradiation may modify the structure and composition of surface materials and there is no unequivocal interpretation of these spectra devoid of vibrational bands. To circumvent these problems, we consider the composition of cometary grains analyzed in the laboratory to constrain the nature of the cometary materials and consider results on surface rejuvenation and solar wind processing provided by the OSIRIS and ROSINA instruments, respectively. Our results lead to five main conclusions: (i) The low albedo of comet 67P/CG is accounted for by a dark refractory polyaromatic carbonaceous component mixed with opaque minerals. VIRTIS data do not provide direct insights into the nature of these opaque minerals. However, according to the composition of cometary grains analyzed in the laboratory, we infer that they consist of Fe-Ni alloys and FeS sulfides. (ii) A semi-volatile component, consisting of a complex mix of low weight molecular species not volatilized at T similar to 220 K, is likely a major carrier of the 3.2 p.m band. Water ice contributes significantly to this feature in the neck region but not in other regions of the comet. COOH in carboxylic acids is the only chemical group that encompasses the broad width of this feature. It appears as a highly plausible candidate along with the NH4+ ion. (iii) Photolytic/thermal residues, produced in the laboratory from interstellar ice analogs, are potentially good spectral analogs. (iv) No hydrated minerals were identified and our data support the lack of genetic links with the CI, CR and CM primitive chondrites. This concerns in particular the Orgueil chondrite, previously suspected to have been of cometary origin. (v) The comparison between fresh and aged terrains revealed no effect of solar wind irradiation on the 3.2 mu m band. This is consistent with the presence of efficient resurfacing processes such as dust transport from the interior to the surface, as revealed by the OSIRIS camera. (C) 2016 Elsevier Inc. All rights reserved. KW - Comets KW - Organic chemistry KW - Infrared observations KW - Meteorites KW - Spectrophotometry Y1 - 2016 U6 - https://doi.org/10.1016/j.icarus.2016.02.028 SN - 0019-1035 SN - 1090-2643 VL - 272 SP - 32 EP - 47 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Candan, O. A1 - Akal, C. A1 - Koralay, O. E. A1 - Okay, A. I. A1 - Oberhänsli, Roland A1 - Prelevic, D. A1 - Mertz-Kraus, R. T1 - Carboniferous granites on the northern margin of Gondwana, Anatolide-Tauride Block, Turkey - Evidence for southward subduction of Paleotethys JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - Carboniferous metagranites with U-Pb zircon crystallization ages of 331-315 Ma crop out in the Afyon zone in the northern margin of the Anatolide-Tauride Block, which is commonly regarded as part of Gondwana during the Late Palaeozoic. They are peraluminous, calc-alkaline and are characterized by increase in Rb and Ba, decrease in Nb-Ta, and enrichment in Sr and high LILE/HFSE ratios compatible with a continental arc setting. The metagranites intrude a metasedimentary sequence of phyllite, metaquartzite and marble; both the Carboniferous metagranites and metasedimentary rocks are overlain unconformably by Lower Triassic metaconglomerates, metavolcanics and Upper Triassic to Cretaceous recrystallized limestones. The low-grade metamorphism and deformation occurred at the Cretaceous-Tertiary boundary. There is no evidence for Carboniferous deformation and metamorphism in the region. Carboniferous arc-type granites and previously described Carboniferous subduction-accretion complexes on the northern margin of the Anatolide-Tauride Block suggest southward subduction of Paleotethys under Gondwana during the Carboniferous. Considering the Variscan-related arc granites in Pelagonian and Sakarya zones on the active southern margin of Laurasia, a dual subduction of Paleotethys can be envisaged between Early Carboniferous and Late Permian. However, the southward subduction was short-lived and by the Late Permian the Gondwana margin became passive. (C) 2016 Elsevier B.V. All rights reserved. KW - Carboniferous magmatism KW - Paleotethys KW - Gondwana KW - Afyon zone KW - Anatolide-Tauride Block Y1 - 2016 U6 - https://doi.org/10.1016/j.tecto.2016.06.030 SN - 0040-1951 SN - 1879-3266 VL - 683 SP - 349 EP - 366 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - de Figueiredo, Jose Vidal A1 - de Araujo, Jose Carlos A1 - Medeiros, Pedro Henrique Augusto A1 - Costa, Alexandre C. T1 - Runoff initiation in a preserved semiarid Caatinga small watershed, Northeastern Brazil JF - Hydrological processes N2 - This study analyses some hydrological driving forces and their interrelation with surface-flow initiation in a semiarid Caatinga basin (12km(2)), Northeastern Brazil. During the analysis period (2005 - 2014), 118 events with precipitation higher than 10mm were monitored, providing 45 events with runoff, 25 with negligible runoff and 49 without runoff. To verify the dominant processes, 179 on-site measurements of saturated hydraulic conductivity (Ksat) were conducted. The results showed that annual runoff coefficient lay below 0.5% and discharge at the outlet has only occurred four days per annum on average, providing an insight to the surface-water scarcity of the Caatinga biome. The most relevant variables to explain runoff initiation were total precipitation and maximum 60-min rainfall intensity (I-60). Runoff always occurred when rainfall surpassed 31mm, but it never occurred for rainfall below 14mm or for I-60 below 12mmh(-1). The fact that the duration of the critical intensity is similar to the basin concentration time (65min) and that the infiltration threshold value approaches the river-bank saturated hydraulic conductivity support the assumption that Hortonian runoff prevails. However, none of the analysed variables (total or precedent precipitation, soil moisture content, rainfall intensities or rainfall duration) has been able to explain the runoff initiation in all monitored events: the best criteria, e.g. failed to explain 27% of the events. It is possible that surface-flow initiation in the Caatinga biome is strongly influenced by the root-system dynamics, which changes macro-porosity status and, therefore, initial abstraction. Copyright (c) 2016 John Wiley & Sons, Ltd. KW - hydraulic conductivity KW - soil moisture KW - root system KW - semi-arid KW - Caatinga KW - connectivity Y1 - 2016 U6 - https://doi.org/10.1002/hyp.10801 SN - 0885-6087 SN - 1099-1085 VL - 30 SP - 2390 EP - 2400 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Siegmund, Jonatan F. A1 - Sanders, Tanja G. M. A1 - Heinrich, Ingo A1 - van der Maaten, Ernst A1 - Simard, Sonia A1 - Helle, Gerhard A1 - Donner, Reik Volker T1 - Meteorological Drivers of Extremes in Daily Stem Radius Variations of Beech, Oak, and Pine in Northeastern Germany: An Event Coincidence Analysis JF - Frontiers in plant science N2 - Observed recent and expected future increases in frequency and intensity of climatic extremes in central Europe may pose critical challenges for domestic tree species. Continuous dendrometer recordings provide a valuable source of information on tree stem radius variations, offering the possibility to study a tree's response to environmental influences at a high temporal resolution. In this study, we analyze stem radius variations (SRV) of three domestic tree species (beech, oak, and pine) from 2012 to 2014. We use the novel statistical approach of event coincidence analysis (ECA) to investigate the simultaneous occurrence of extreme daily weather conditions and extreme SRVs, where extremes are defined with respect to the common values at a given phase of the annual growth period. Besides defining extreme events based on individual meteorological variables, we additionally introduce conditional and joint ECA as new multivariate extensions of the original methodology and apply them for testing 105 different combinations of variables regarding their impact on SRV extremes. Our results reveal a strong susceptibility of all three species to the extremes of several meteorological variables. Yet, the inter-species differences regarding their response to the meteorological extremes are comparatively low. The obtained results provide a thorough extension of previous correlation-based studies by emphasizing on the timings of climatic extremes only. We suggest that the employed methodological approach should be further promoted in forest research regarding the investigation of tree responses to changing environmental conditions. KW - dendrometer measurements KW - event coincidence analysis KW - climate extremes KW - growth response Y1 - 2016 U6 - https://doi.org/10.3389/fpls.2016.00733 SN - 1664-462X VL - 7 SP - 4701 EP - 4712 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Lischeid, Gunnar A1 - Kalettka, Thomas A1 - Merz, Christoph A1 - Steidl, Jörg T1 - Monitoring the phase space of ecosystems: Concept and examples from the Quillow catchment, Uckermark JF - Ecological indicators : integrating monitoring, assessment and management N2 - Ecosystem research benefits enormously from the fact that comprehensive data sets of high quality, and covering long time periods are now increasingly more available. However, facing apparently complex interdependencies between numerous ecosystem components, there is urgent need rethinking our approaches in ecosystem research and applying new tools of data analysis. The concept presented in this paper is based on two pillars. Firstly, it postulates that ecosystems are multiple feedback systems and thus are highly constrained. Consequently, the effective dimensionality of multivariate ecosystem data sets is expected to be rather low compared to the number of observables. Secondly, it assumes that ecosystems are characterized by continuity in time and space as well as between entities which are often treated as distinct units. Implementing this concept in ecosystem research requires new tools for analysing large multivariate data sets. This study presents some of them, which were applied to a comprehensive water quality data set from a long-term monitoring program in Northeast Germany in the Uckermark region, one of the LTER-D (Long Term Ecological Research network, Germany) sites. Short-term variability of the kettle hole water samples differed substantially from that of the stream water samples, suggesting different processes generating the dynamics in these two types of water bodies. However, again, this seemed to be due to differing intensities of single processes rather than to completely different processes. We feel that research aiming at elucidating apparently complex interactions in ecosystems could make much more efficient use from now available large monitoring data sets by implementing the suggested concept and using corresponding innovative tools of system analysis. (C) 2015 Elsevier Ltd. All rights reserved. KW - Ecosystem research KW - Monitoring KW - Concept KW - Effective dimensionality KW - Continuity KW - Visualization Y1 - 2016 U6 - https://doi.org/10.1016/j.ecolind.2015.10.067 SN - 1470-160X SN - 1872-7034 VL - 65 SP - 55 EP - 65 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Candan, O. A1 - Koralay, O. E. A1 - Topuz, G. A1 - Oberhänsli, Roland A1 - Fritz, H. A1 - Collins, A. S. A1 - Chen, F. T1 - Late Neoproterozoic gabbro emplacement followed by early Cambrian eclogite-facies metamorphism in the Menderes Massif (W. Turkey): Implications on the final assembly of Gondwana JF - Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research N2 - Numerous (meta-)gabbroic dikes or stocks occur within the latest Neoproterozoic-early Cambrian series of the Menderes Massif (Anatolide-Tauride Block, western Turkey). These well-preserved rocks were locally converted into eclogitic metagabbros and garnet amphibolites along the contacts or shear zones. Both bulk-rock composition and compositions of igneous clinopyroxenes suggest continental tholeiitic affinity. U-Pb dating of igneous zircons from gabbroic rocks yielded a mean age of 563 +/- 1 Ma (2 sigma), indicating emplacement during the latest Neoproterozoic (Ediacaran). On the other hand, rims of zircons from eclogitic metagabbro gave 535 +/- 3 Ma (2 sigma) (early Cambrian), in addition to 558 +/- 3 Ma (2 sigma) obtained from the igneous core of zircons. These ages are interpreted as the time of high-P metamorphism and crystallization age of gabbroic protolith, respectively. Given the estimated paleogeographic position of the Anatolide-Tauride Block during the late Neoproterozoic and early Cambrian, this orogenic event can be spatially and temporally related to the northward continuity of 600-500 Ma orogenic event (Malagasy/Kuunga orogeny) extending from western margin of India, Madagascar, via Arabia up to northern margin of Gondwana beneath thick Phanerozoic cover series in Arabian Peninsula. Therefore, the high-P evolution of the basement of the Menderes Massif and associated basic intrusions can be interpreted to mark the latest stages of consumption of the basin/oceanic branches and final amalgamation of the Gondwana during the late Neoproterozoic-early Cambrian around the Arabian region. (C) 2015 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. KW - Gabbro KW - Eclogite KW - Malagasy/Kuunga orogeny KW - Menderes Massif KW - Turkey Y1 - 2016 U6 - https://doi.org/10.1016/j.gr.2015.02.015 SN - 1342-937X SN - 1878-0571 VL - 34 SP - 158 EP - 173 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ferrero, Silvio A1 - Wunder, Bernd A1 - Ziemann, Martin Andreas A1 - Waelle, Markus T1 - Carbonatitic and granitic melts produced under conditions of primary immiscibility during anatexis in the lower crust JF - Earth & planetary science letters N2 - Carbonatites are peculiar magmatic rocks with mantle-related genesis, commonly interpreted as the products of melting of CO2-bearing peridotites, or resulting from the chemical evolution of mantle derived magmas, either through extreme "differentiation or secondary immiscibility. Here we report the first finding of anatectic carbonatites of crustal origin, preserved as calcite-rich polycrystalline inclusions in garnet from low-to-medium pressure migmatites of the Oberpfalz area, SW Bohemian Massif (Central Europe). These inclusions originally trapped a melt of calciocarbonatitic composition with a characteristic enrichment in Ba, Sr and LREE. This interpretation is supported by the results of a detailed microstructural and microchemical investigation, as well as re-melting experiments using a piston cylinder apparatus. Carbonatitic inclusions coexist in the same cluster with crystallized silicate melt inclusions (nanogranites) and COH fluid inclusions, suggesting conditions of primary immiscibility between two melts and a fluid during anatexis. The production of both carbonatitic and granitic melts during the same anatectic event requires a suitable heterogeneous protolith. This may be represented by a sedimentary sequence containing marble lenses of limited extension, similar to the one still visible in the adjacent central Moldanubian Zone. The presence of CO2-rich fluid inclusions suggests furthermore that high CO2 activity during anatexis may be required to stabilize a carbonate-rich melt in a silica-dominated, system. This natural occurrence displays a remarkable similarity with experiments on carbonate-silicate melt immiscibility, where CO2 saturation is a condition commonly imposed. In conclusion, this study shows how the investigation of partial melting through melt inclusion studies may unveil unexpected processes whose evidence, while preserved in stiff minerals such as garnet, is completely obliterated in the rest of the rock due to metamorphic re-equilibration. Our results thus provide invaluable new insights into the processes which shape the geochemical evolution of our planet, such as the redistribution of carbon and strategic metals during orogenesis. (C) 2016 Elsevier B.V. All rights reserved. KW - partial melting KW - carbonatites KW - nanogranites KW - garnet KW - melt inclusions; nanocarbonatites Y1 - 2016 U6 - https://doi.org/10.1016/j.epsl.2016.08.043 SN - 0012-821X SN - 1385-013X VL - 454 SP - 121 EP - 131 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Singh, Alka A1 - Seitz, Florian A1 - Eicker, Annette A1 - Güntner, Andreas T1 - Water Budget Analysis within the Surrounding of Prominent Lakes and Reservoirs from Multi-Sensor Earth Observation Data and Hydrological Models: Case Studies of the Aral Sea and Lake Mead JF - Remote sensing N2 - The hydrological budget of a region is determined based on the horizontal and vertical water fluxes acting in both inward and outward directions. These integrated water fluxes vary, altering the total water storage and consequently the gravitational force of the region. The time-dependent gravitational field can be observed through the Gravity Recovery and Climate Experiment (GRACE) gravimetric satellite mission, provided that the mass variation is above the sensitivity of GRACE. This study evaluates mass changes in prominent reservoir regions through three independent approaches viz. fluxes, storages, and gravity, by combining remote sensing products, in-situ data and hydrological model outputs using WaterGAP Global Hydrological Model (WGHM) and Global Land Data Assimilation System (GLDAS). The results show that the dynamics revealed by the GRACE signal can be better explored by a hybrid method, which combines remote sensing-based reservoir volume estimates with hydrological model outputs, than by exclusive model-based storage estimates. For the given arid/ semi-arid regions, GLDAS based storage estimations perform better than WGHM. KW - GRACE KW - water budget KW - reservoir KW - water fluxes KW - GLDAS KW - WGHM KW - Aral Sea KW - Lake Mead Y1 - 2016 U6 - https://doi.org/10.3390/rs8110953 SN - 2072-4292 VL - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schaffer, Mario A1 - Idzik, Krzysztof R. A1 - Wilke, Max A1 - Licha, Tobias T1 - Amides as thermo-sensitive tracers for investigating the thermal state of geothermal reservoirs JF - Geothermics : an international journal of geothermal research and its applications N2 - The application of thermo-sensitive tracers is a promising technique for evaluating the thermal state of geothermal reservoirs. To extend the compound spectrum for hydrolyzable compounds to reservoir temperatures between 100 and 200 degrees C carboxamides were studied. The kinetic parameters of 17 self-synthesized amides were determined in hydrothermal batch and autoclave experiments. The influence of the molecular structure and the role of pH/pOH on hydrolysis kinetics were studied. Additionally, the thermal stabilities of the hydrolysis products were evaluated. The results demonstrate the high potential of tracers based on amide hydrolysis for use in medium enthalpy reservoirs. (C) 2016 Elsevier Ltd. All rights reserved. KW - Thermo-sensitive tracers KW - Amides KW - Hydrolysis KW - Kinetics KW - Reservoir temperature KW - Molecular design Y1 - 2016 U6 - https://doi.org/10.1016/j.geothermics.2016.05.004 SN - 0375-6505 SN - 1879-3576 VL - 64 SP - 180 EP - 186 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Schmidt, Katja A1 - Walz, Ariane A1 - Jones, Isobel A1 - Metzger, Marc J. T1 - The Sociocultural Value of Upland Regions in the Vicinity of Cities in Comparison With Urban Green Spaces JF - Mountain research and development KW - Ecosystem services KW - mountains near cities KW - urban green spaces KW - social valuation KW - perception KW - preferences in land management KW - Scotland Y1 - 2016 U6 - https://doi.org/10.1659/MRD-JOURNAL-D-16-00044.1 SN - 0276-4741 SN - 1994-7151 VL - 36 SP - 465 EP - 474 PB - American Geophysical Union CY - Lawrence ER - TY - JOUR A1 - Park, Jaeheung A1 - Lühr, Hermann A1 - Stolle, Claudia A1 - Rodriguez-Zuluaga, Juan A1 - Knudsen, David J. A1 - Burchill, Johnathan K. A1 - Kwak, Young-Sil T1 - Statistical survey of nighttime midlatitude magnetic fluctuations: Their source location and Poynting flux as derived from the Swarm constellation JF - Journal of geophysical research : Space physics N2 - This is the first statistical survey of field fluctuations related with medium-scale traveling ionospheric disturbances (MSTIDs), which considers magnetic field, electric field, and plasma density variations at the same time. Midlatitude electric fluctuations (MEFs) and midlatitude magnetic fluctuations (MMFs) observed in the nighttime topside ionosphere have generally been attributed to MSTIDs. Although the topic has been studied for several decades, statistical studies of the Poynting flux related with MEF/MMF/MSTID have not yet been conducted. In this study we make use of electric/magnetic field and plasma density observations by the European Space Agency's Swarm constellation to address the statistical behavior of the Poynting flux. We have found that (1) the Poynting flux is directed mainly from the summer to winter hemisphere, (2) its magnitude is larger before midnight than thereafter, and (3) the magnitude is not well correlated with fluctuation level of in situ plasma density. These results are discussed in the context of previous studies. Y1 - 2016 U6 - https://doi.org/10.1002/2016JA023408 SN - 2169-9380 SN - 2169-9402 VL - 121 SP - 11235 EP - 11248 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Derras, Boumediene A1 - Bard, Pierre-Yves A1 - Cotton, Fabrice Pierre T1 - Site-Condition Proxies, Ground Motion Variability, and Data-Driven GMPEs: Insights from the NGA-West2 and RESORCE Data Sets JF - Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute N2 - We compare the ability of various site-condition proxies (SCPs) to reduce the aleatory variability of ground motion prediction equations (GMPEs). Three SCPs (measured V-S30, inferred V-S30, local topographic slope) and two accelerometric databases (RESORCE and NGA-West2) are considered. An artificial neural network (ANN) approach including a random-effect procedure is used to derive GMPEs setting the relationship between peak ground acceleration (PGA), peak ground velocity (PGV), pseudo-spectral acceleration [PSA(T)], and explanatory variables (M-w, R-JB, and V-S30 or Slope). The analysis is performed using both discrete site classes and continuous proxy values. All "non-measured" SCPs exhibit a rather poor performance in reducing aleatory variability, compared to the better performance of measured V-S30. A new, fully data-driven GMPE based on the NGA-West2 is then derived, with an aleatory variability value depending on the quality of the SCP. It proves very consistent with previous GMPEs built on the same data set. Measuring V-S30 allows for benefit from an aleatory variability reduction up to 15%. Y1 - 2016 U6 - https://doi.org/10.1193/060215EQS082M SN - 8755-2930 SN - 1944-8201 VL - 32 SP - 2027 EP - 2056 PB - Earthquake Engineering Research Institute CY - Oakland ER - TY - JOUR A1 - Zimmermann, Alexander A1 - Voss, Sebastian A1 - Metzger, Johanna Clara A1 - Hildebrandt, Anke A1 - Zimmermann, Beate T1 - estimating mean throughfall JF - Journal of hydrology N2 - The selection of an appropriate spatial extent of a sampling plot is one among several important decisions involved in planning a throughfall sampling scheme. In fact, the choice of the extent may determine whether or not a study can adequately characterize the hydrological fluxes of the studied ecosystem. Previous attempts to optimize throughfall sampling schemes focused on the selection of an appropriate sample size, support, and sampling design, while comparatively little attention has been given to the role of the extent. In this contribution, we investigated the influence of the extent on the representativeness of mean throughfall estimates for three forest ecosystems of varying stand structure. Our study is based on virtual sampling of simulated throughfall fields. We derived these fields from throughfall data sampled in a simply structured forest (young tropical forest) and two heterogeneous forests (old tropical forest, unmanaged mixed European beech forest). We then sampled the simulated throughfall fields with three common extents and various sample sizes for a range of events and for accumulated data. Our findings suggest that the size of the study area should be carefully adapted to the complexity of the system under study and to the required temporal resolution of the throughfall data (i.e. event-based versus accumulated). Generally, event-based sampling in complex structured forests (conditions that favor comparatively long autocorrelations in throughfall) requires the largest extents. For event-based sampling, the choice of an appropriate extent can be as important as using an adequate sample size. (C) 2016 Elsevier B.V. All rights reserved. KW - Throughfall KW - Sampling KW - Extent KW - Hydrological monitoring KW - Tropical forest KW - European beech forest Y1 - 2016 U6 - https://doi.org/10.1016/j.jhydrol.2016.09.047 SN - 0022-1694 SN - 1879-2707 VL - 542 SP - 781 EP - 789 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lenz, Josefine A1 - Wetterich, Sebastian A1 - Jones, Benjamin M. A1 - Meyer, Hanno A1 - Bobrov, Anatoly A1 - Grosse, Guido T1 - Evidence of multiple thermokarst lake generations from an 11800-year-old permafrost core on the northern Seward Peninsula, Alaska JF - Boreas N2 - Permafrost degradation influences the morphology, biogeochemical cycling and hydrology of Arctic landscapes over a range of time scales. To reconstruct temporal patterns of early to late Holocene permafrost and thermokarst dynamics, site-specific palaeo-records are needed. Here we present a multi-proxy study of a 350-cm-long permafrost core from a drained lake basin on the northern Seward Peninsula, Alaska, revealing Lateglacial toHolocene thermokarst lake dynamics in a central location of Beringia. Use of radiocarbon dating, micropalaeontology (ostracods and testaceans), sedimentology (grain-size analyses, magnetic susceptibility, tephra analyses), geochemistry (total nitrogen and carbon, total organic carbon, C-13(org)) and stable water isotopes (O-18, D, dexcess) of ground ice allowed the reconstruction of several distinct thermokarst lake phases. These include a pre-lacustrine environment at the base of the core characterized by the Devil Mountain Maar tephra (22800 +/- 280cal. a BP, Unit A), which has vertically subsided in places due to subsequent development of a deep thermokarst lake that initiated around 11800cal. a BP (Unit B). At about 9000cal. a BP this lake transitioned from a stable depositional environment to a very dynamic lake system (Unit C) characterized by fluctuating lake levels, potentially intermediate wetland development, and expansion and erosion of shore deposits. Complete drainage of this lake occurred at 1060cal. a BP, including post-drainage sediment freezing from the top down to 154cm and gradual accumulation of terrestrial peat (Unit D), as well as uniform upward talik refreezing. This core-based reconstruction of multiple thermokarst lake generations since 11800cal. a BP improves our understanding of the temporal scales of thermokarst lake development from initiation to drainage, demonstrates complex landscape evolution in the ice-rich permafrost regions of Central Beringia during the Lateglacial and Holocene, and enhances our understanding of biogeochemical cycles in thermokarst-affected regions of the Arctic. Y1 - 2016 U6 - https://doi.org/10.1111/bor.12186 SN - 0300-9483 SN - 1502-3885 VL - 45 SP - 584 EP - 603 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Dietze, Elisabeth A1 - Slowinski, Michal A1 - Zawiska, Izabela A1 - Veh, Georg A1 - Brauer, Achim T1 - Multiple drivers of Holocene lake level changes at a lowland lake in northeastern Germany JF - Boreas N2 - Many German lakes experienced significant water level declines in recent decades that are not fully understood due to the short observation period. At a typical northeastern German groundwater-fed lake with a complex basin morphology, an acoustic sub-bottom profile was analysed together with a transect of five sediment cores, which were correlated using multiple proxies (sediment facies, -XRF, macrofossils, subfossil Cladocera). Shifts in the boundary between sand and mud deposition were controlled by lake level changes, and hence, allowed the quantification of an absolute lake level amplitude of similar to 8m for the Holocene. This clearly exceeded observed modern fluctuations of 1.3m (AD 1973-2010). Past lake level changes were traced continuously using the calcium-record. During high lake levels, massive organic muds were deposited in the deepest lake basin, whereas lower lake levels isolated the sub-basins and allowed carbonate deposition. During the beginning of the Holocene (>9700cal. a BP), lake levels were high, probably due to final melting of permafrost and dead-ice remains. The establishment of water-use intensive Pinus forests caused generally low (3-4m below modern) but fluctuating lake levels (9700-6400cal. a BP). Afterwards, the lake showed an increasing trend and reached a short-term highstand at c.5000cal. a BP (4m above modern). At the transition towards a cooler and wetter late Holocene, forests dominated by Quercus and Fagus and initial human impact probably contributed more positively to groundwater recharge. Lake levels remained high between 3800 and 800cal. a BP, but the lake system was not sensitive enough to record short-term fluctuations during this period. Lake level changes were recorded again when humans profoundly affected the drainage system, land cover and lake trophy. Hence, local Holocene water level changes reflect feedbacks between catchment and vegetation characteristics and human impact superimposed by climate change at multiple temporal scales. Y1 - 2016 U6 - https://doi.org/10.1111/bor.12190 SN - 0300-9483 SN - 1502-3885 VL - 45 SP - 828 EP - 845 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Kuehn, Nicolas M. A1 - Scherbaum, Frank T1 - A partially non-ergodic ground-motion prediction equation for Europe and the Middle East JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - A partially non-ergodic ground-motion prediction equation is estimated for Europe and the Middle East. Therefore, a hierarchical model is presented that accounts for regional differences. For this purpose, the scaling of ground-motion intensity measures is assumed to be similar, but not identical in different regions. This is achieved by assuming a hierarchical model, where some coefficients are treated as random variables which are sampled from an underlying global distribution. The coefficients are estimated by Bayesian inference. This allows one to estimate the epistemic uncertainty in the coefficients, and consequently in model predictions, in a rigorous way. The model is estimated based on peak ground acceleration data from nine different European/Middle Eastern regions. There are large differences in the amount of earthquakes and records in the different regions. However, due to the hierarchical nature of the model, regions with only few data points borrow strength from other regions with more data. This makes it possible to estimate a separate set of coefficients for all regions. Different regionalized models are compared, for which different coefficients are assumed to be regionally dependent. Results show that regionalizing the coefficients for magnitude and distance scaling leads to better performance of the models. The models for all regions are physically sound, even if only very few earthquakes comprise one region. KW - Ground-motion prediction equation KW - Non-ergodic PSHA KW - Hierarchical model Y1 - 2016 U6 - https://doi.org/10.1007/s10518-016-9911-x SN - 1570-761X SN - 1573-1456 VL - 14 SP - 2629 EP - 2642 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Comber, Alexis A1 - Mooney, Peter A1 - Purves, Ross S. A1 - Rocchini, Duccio A1 - Walz, Ariane T1 - Crowdsourcing: It Matters Who the Crowd Are. The Impacts of between Group Variations in Recording Land Cover JF - PLoS one N2 - Volunteered geographical information (VGI) and citizen science have become important sources data for much scientific research. In the domain of land cover, crowdsourcing can provide a high temporal resolution data to support different analyses of landscape processes. However, the scientists may have little control over what gets recorded by the crowd, providing a potential source of error and uncertainty. This study compared analyses of crowdsourced land cover data that were contributed by different groups, based on nationality (labelled Gondor and Non-Gondor) and on domain experience (labelled Expert and Non-Expert). The analyses used a geographically weighted model to generate maps of land cover and compared the maps generated by the different groups. The results highlight the differences between the maps how specific land cover classes were under-and over-estimated. As crowdsourced data and citizen science are increasingly used to replace data collected under the designed experiment, this paper highlights the importance of considering between group variations and their impacts on the results of analyses. Critically, differences in the way that landscape features are conceptualised by different groups of contributors need to be considered when using crowdsourced data in formal scientific analyses. The discussion considers the potential for variation in crowdsourced data, the relativist nature of land cover and suggests a number of areas for future research. The key finding is that the veracity of citizen science data is not the critical issue per se. Rather, it is important to consider the impacts of differences in the semantics, affordances and functions associated with landscape features held by different groups of crowdsourced data contributors. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0158329 SN - 1932-6203 VL - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Rajabi, Mojtaba A1 - Ziegler, Moritz O. A1 - Tingay, Mark A1 - Heidbach, Oliver A1 - Reynolds, Scott T1 - Contemporary tectonic stress pattern of the Taranaki Basin, New Zealand JF - Journal of geophysical research : Solid earth N2 - The present-day stress state is a key parameter in numerous geoscientific research fields including geodynamics, seismic hazard assessment, and geomechanics of georeservoirs. The Taranaki Basin of New Zealand is located on the Australian Plate and forms the western boundary of tectonic deformation due to Pacific Plate subduction along the Hikurangi margin. This paper presents the first comprehensive wellbore-derived basin-scale in situ stress analysis in New Zealand. We analyze borehole image and oriented caliper data from 129 petroleum wells in the Taranaki Basin to interpret the shape of boreholes and determine the orientation of maximum horizontal stress (S-Hmax). We combine these data (151 S-Hmax data records) with 40 stress data records derived from individual earthquake focal mechanism solutions, 6 from stress inversions of focal mechanisms, and 1 data record using the average of several focal mechanism solutions. The resulting data set has 198 data records for the Taranaki Basin and suggests a regional S-Hmax orientation of N068 degrees E (22 degrees), which is in agreement with NW-SE extension suggested by geological data. Furthermore, this ENE-WSW average S-Hmax orientation is subparallel to the subduction trench and strike of the subducting slab (N50 degrees E) beneath the central western North Island. Hence, we suggest that the slab geometry and the associated forces due to slab rollback are the key control of crustal stress in the Taranaki Basin. In addition, we find stress perturbations with depth in the vicinity of faults in some of the studied wells, which highlight the impact of local stress sources on the present-day stress rotation. KW - in situ stress KW - Taranaki Basin KW - New Zealand KW - plate tectonics KW - subduction zone Y1 - 2016 U6 - https://doi.org/10.1002/2016JB013178 SN - 2169-9313 SN - 2169-9356 VL - 121 SP - 6053 EP - 6070 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Xiong, Chao A1 - Stolle, Claudia A1 - Luehr, Hermann A1 - Park, Jaeheung A1 - Fejer, Bela G. A1 - Kervalishvili, Guram N. T1 - Scale analysis of equatorial plasma irregularities derived from Swarm constellation JF - Earth, planets and space N2 - In this study, we investigated the scale sizes of equatorial plasma irregularities (EPIs) using measurements from the Swarm satellites during its early mission and final constellation phases. We found that with longitudinal separation between Swarm satellites larger than 0.4 degrees, no significant correlation was found any more. This result suggests that EPI structures include plasma density scale sizes less than 44 km in the zonal direction. During the Swarm earlier mission phase, clearly better EPI correlations are obtained in the northern hemisphere, implying more fragmented irregularities in the southern hemisphere where the ambient magnetic field is low. The previously reported inverted-C shell structure of EPIs is generally confirmed by the Swarm observations in the northern hemisphere, but with various tilt angles. From the Swarm spacecrafts with zonal separations of about 150 km, we conclude that larger zonal scale sizes of irregularities exist during the early evening hours (around 1900 LT). KW - Equatorial plasma irregularities KW - Ionospheric scale lengths KW - Swarm constellation Y1 - 2016 U6 - https://doi.org/10.1186/s40623-016-0502-5 SN - 1880-5981 VL - 68 SP - 189 EP - 202 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - van Schaik, Loes A1 - Palm, Juliane A1 - Klaus, Julian A1 - Zehe, Erwin A1 - Schroeder, Boris T1 - Potential effects of tillage and field borders on within-field spatial distribution patterns of earthworms JF - Biological chemistry N2 - Earthworms play a key role in regulating soil ecosystem functions and services. The small scale variability in earthworm abundance is often found to be very high, which is a problem for representative sampling of earthworm abundance at larger scales. In agricultural fields, soil tillage may influence both the average earthworm abundance as well as the spatial distribution of earthworms. Therefore we studied the abundance and spatial pattern of the different ecological earthworm types, i.e. endogeic, epigeic and anecic earthworms, in four agricultural fields differing in soil tillage (two fields with regular tillage and two fields with conservation tillage) and surrounding land use (other cropped fields or apple orchard and forest). To this aim we sampled earthworms on a total number of 430 plots (50 x 50 cm(2)) using a combination of extraction with mustard solution and hand sorting. The results exhibit large differences in average earthworm abundance between the four fields. Only one of the two fields with conservation tillage had a comparatively very high overall abundance of earthworms. Furthermore, we found a high spatial variability of earthworms within the field scale often exhibiting a patchy distribution. We detected a trend of decreasing earthworm abundances from the field border into the field for different earthworm groups on each of the fields. In three fields with low total earthworm abundance (and only very few epigeic earthworms) there was a short scale autocorrelation with ranges varying strongly for the endogeic earthworms (37.9 m, 62.6 m, and 85.2 m) compared to anecic earthworms (19.8 m, 22.8 m, and 27.4 m). In the field with high abundance, after trend removal, the variogram models for anecic and endogeic earthworms were rejected based on their negative explained variances. On this field, we found only a short scale autocorrelation for the epigeic earthworms with a range of 143 m. Based on these results it seems that ploughing alone cannot explain the differences in abundance and range of autocorrelation found on the four fields. The trend of strongly decreasing earthworm abundance from the field border into the field in the one field with high abundance does indicate that the field border or surrounding land use may also influence the recolonization of fields, but more research is required to provide further evidence for this hypothesis. Due to the very different patterns of earthworm distributions in the fields it remains difficult to recommend an optimal number and distance of samples to obtain a representative earthworm abundance for the field scale. (C) 2016 Elsevier B.V. All rights reserved. KW - Earthworms KW - Spatial distribution KW - Autocorrelation KW - Agricultural fields KW - Soil tillage Y1 - 2016 U6 - https://doi.org/10.1016/j.agee.2016.05.015 SN - 0167-8809 SN - 1873-2305 VL - 228 SP - 82 EP - 90 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Schneider, Birgit T1 - Burning worlds of cartography: a critical approach to climate cosmograms of the Anthropocene JF - Geo : geography and environment N2 - Climate science today makes use of a variety of red globes to explore and communicate findings. These transform the iconography which informs this image: the idealised, even mythical vision of the blue, vulnerable and perfect marble is impaired by the application of the colours yellow and red. Since only predictions that employ a lot of red seem to exist, spectators are confronted with the message that the future Earth that might turn out as envisaged here is undesirable. Here intuitively powerful narrations of the end of the world may connect. By employing methods of art history and visual analysis, and building on examples from current Intergovernmental Panel on Climate Change reports and future scenario maps, this article explores how burning world images bear - intentionally or not - elements of horror and shock. My question explored here is as follows: should 'burning world' images be understood as a new and powerful cosmology? KW - cartography KW - visualisation KW - climate change KW - whole Earth images Y1 - 2016 U6 - https://doi.org/10.1002/geo2.27 SN - 2054-4049 VL - 3 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bartoli, Omar A1 - Acosta-Vigil, Antonio A1 - Ferrero, Silvio A1 - Cesare, Bernardo T1 - Granitoid magmas preserved as melt inclusions in high-grade metamorphic rocks JF - American mineralogist : an international journal of earth and planetary materials N2 - This review presents a compositional database of primary anatectic granitoid magmas, entirely based on melt inclusions (MI) in high-grade metamorphic rocks. Although MI are well known to igneous petrologists and have been extensively studied in intrusive and extrusive rocks, MI in crustal rocks that have undergone anatexis (migmatites and granulites) are a novel subject of research. They are generally trapped along the heating path by peritectic phases produced by incongruent melting reactions. Primary MI in high-grade metamorphic rocks are small, commonly 5-10 pm in diameter, and their most common mineral host is peritectic garnet. In most cases inclusions have crystallized into a cryptocrystalline aggregate and contain a granitoid phase assemblage (nanogranitoid inclusions) with quartz, K-feldspar, plagioclase, and one or two mica depending on the particular circumstances. After their experimental remelting under high-confining pressure, nanogranitoid MI can be analyzed combining several techniques (EMP, LA-ICP-MS, NanoSIMS, Raman). The trapped melt is granitic and metaluminous to peraluminous, and sometimes granodioritic, tonalitic, and trondhjemitic in composition, in agreement with the different P-T-a(H2o) conditions of melting and protolith composition, and overlap the composition of experimental glasses produced at similar conditions. Being trapped along the up-temperature trajectory as opposed to classic MI in igneous rocks formed during down-temperature magma crystallization fundamental information provided by nanogranitoid MI is the pristine composition of the natural primary anatectic melt for the specific rock under investigation. So far similar to 600 nanogranitoid MI, coming from several occurrences from different geologic and geodynamic settings and ages, have been characterized. Although the compiled MI database should be expanded to other potential sources of crustal magmas, MI data collected so far can be already used as natural "starting-point" compositions to track the processes involved in formation and evolution of granitoid magmas. KW - Granitoid magmas KW - melt inclusions KW - nanogranite KW - crustal anatexis KW - peritectic phase Y1 - 2016 U6 - https://doi.org/10.2138/am-2016-5541CCBYNCND SN - 0003-004X SN - 1945-3027 VL - 101 SP - 1543 EP - 1559 PB - Mineralogical Society of America CY - Chantilly ER - TY - JOUR A1 - Estrany, Joan A1 - López-Tarazón, José Andrés A1 - Smith, Hugh G. T1 - WILDFIRE EFFECTS ON SUSPENDED SEDIMENT DELIVERY QUANTIFIED USING FALLOUT RADIONUCLIDE TRACERS IN A MEDITERRANEAN CATCHMENT JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Over short and long timescales, wildfires can be an important cause of hydrological and geomorphological change. Mediterranean rivers are part of a fire-prone and high-energy environment in which the timing of major storms in relation to fire influences the impact on fluvial systems; accordingly, the identification of major sources, stores and fluxes of sediments is essential for providing more effective post-fire management strategies. In this study, caesium-137 and excess lead-210 were used as tracers to quantify the proportional contributions of fine sediment from hillslope surface and channel bank sources to suspended sediment and channel bed deposits before the impact of a forest wildfire in Na Borges, a Mediterranean groundwater-dominated river. It also compared burnt and unburnt spatial sources of sediment within a single catchment and the extent to which burnt material was transported downstream. The study focused on two small and steep sub-catchments, where just one of the catchments was partially affected by a wildfire. The pre-fire dynamics indicated that surface soils were the main sediment source in these ephemeral creeks. Post-fire sediment dynamics were characterised by a single flood event with a short recurrence interval (i.e. return period ca. <1 year). Sediment generated from the burnt area contributed 12% on average to bed-stored sediments within the burnt catchment, which reduced downstream to 5% along the main channel of the Na Borges River. The findings demonstrate the potential for using fallout radionuclide tracers to understand the wider impacts of wildfires on fluvial environments located outside of the burn area. Copyright (C) 2015 John Wiley & Sons, Ltd. KW - wildfire KW - sediment delivery processes KW - sediment source fingerprinting KW - fallout radionuclides KW - Mediterranean fluvial systems Y1 - 2016 U6 - https://doi.org/10.1002/ldr.2462 SN - 1085-3278 SN - 1099-145X VL - 27 SP - 1501 EP - 1512 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Licht, Alexis A1 - Dupont-Nivet, Guillaume A1 - Pullen, A. A1 - Kapp, P. A1 - Abels, Hemmo A. A1 - Lai, Z. A1 - Guo, Z. A1 - Abell, Jordan A1 - Giesler, D. T1 - Resilience of the Asian atmospheric circulation shown by Paleogene dust provenance JF - Nature Communications N2 - The onset of modern central Asian atmospheric circulation is traditionally linked to the interplay of surface uplift of the Mongolian and Tibetan-Himalayan orogens, retreat of the Paratethys sea from central Asia and Cenozoic global cooling. Although the role of these players has not yet been unravelled, the vast dust deposits of central China support the presence of arid conditions and modern atmospheric pathways for the last 25 million years (Myr). Here, we present provenance data from older (42-33 Myr) dust deposits, at a time when the Tibetan Plateau was less developed, the Paratethys sea still present in central Asia and atmospheric pCO(2) much higher. Our results show that dust sources and near-surface atmospheric circulation have changed little since at least 42 Myr. Our findings indicate that the locus of central Asian high pressures and concurrent aridity is a resilient feature only modulated by mountain building, global cooling and sea retreat. Y1 - 2016 U6 - https://doi.org/10.1038/ncomms12390 SN - 2041-1723 VL - 7 SP - 885 EP - 894 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Gao, Mingxing A1 - Zeilinger, Gerold A1 - Xu, Xiwei A1 - Tan, Xibin A1 - Wang, Qingliang A1 - Hao, Ming T1 - Active tectonics evaluation from geomorphic indices for the central and the southern Longmenshan range on the Eastern Tibetan Plateau, China JF - Tectonics N2 - We applied the geomorphic indices (hypsometry and stream length gradient) to evaluate the differential uplift of the central and southern Longmenshan, a mountain range characterized by rapid erosion, strong tectonic uplift, and devastating seismic hazards. The results of the geomorphic analysis indicate that the Beichuan-Yingxiu fault and the Shuangshi-Dachuan fault act as major tectonic boundaries separating areas experiencing rapid uplift from slow uplift. The results of the geomorphic analysis also suggest that the Beichuan-Yingxiu fault is the most active fault with the largest relative uplift rates compared to the rest of the faults in the Longmenshan fault system. We compared reflected relative uplift rates based on the hypsometry and stream length gradient indices with geological/geodetic absolute rates. Along-strike and across-strike variations in the hypsometry and stream length gradient correlate with the spatial patterns derived from the apatite fission track exhumation rates, the leveling-derived uplift rate, and coseismic vertical displacements during the 2008 Wenchuan earthquake. These data defined multiple fault relationships in a complex thrust zone and provided geomorphic evidence to evaluate the potential seismic hazards of the southern Longmenshan range. Y1 - 2016 U6 - https://doi.org/10.1002/2015TC004080 SN - 0278-7407 SN - 1944-9194 VL - 35 SP - 1812 EP - 1826 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Tran Thanh Tuan, A1 - Pham Chi Vinh, A1 - Ohrnberger, Matthias A1 - Malischewsky, Peter A1 - Aoudia, Abdelkrim T1 - An Improved Formula of Fundamental Resonance Frequency of a Layered Half-Space Model Used in H/V Ratio Technique JF - Pure and applied geophysics N2 - The resonance frequency of the transmission response in layered half-space model is important in the study of site effect because it is the frequency where the shake-ability of the ground is enhanced significantly. In practice, it is often determined by the H/V ratio technique in which the peak frequency of recorded H/V spectral ratio is interpreted as the resonance frequency. Despite of its importance, there has not been any formula of the resonance frequency of the layered half-space structure. In this paper, a simple approximate formula of the fundamental resonance frequency is presented after an exact formula in explicit form of the response function of vertically SH incident wave is obtained. The formula is in similar form with the one used in H/V ratio technique but it reflects several major effects of the model to the resonance frequency such as the arrangement of layers, the impedance contrast between layers and the half-space. Therefore, it could be considered as an improved formula used in H/V ratio technique. The formula also reflects the consistency between two approaches of the H/V ratio technique based on SH body waves or Rayleigh surface waves on the peak frequency under high impedance contrast condition. This formula is in explicit form and, therefore, may be used in the direct and inverse problem efficiently. A numerical illustration of the improved formula for an actual layered half-space model already investigated by H/V ratio technique is presented to demonstrate its new features and its improvement to the currently used formula. KW - Response function KW - H/V ratio technique KW - Orthotropy KW - SH waves KW - Quarter-wavelength principle Y1 - 2016 U6 - https://doi.org/10.1007/s00024-016-1313-0 SN - 0033-4553 SN - 1420-9136 VL - 173 SP - 2803 EP - 2812 PB - Springer CY - Basel ER - TY - JOUR A1 - Konrad-Schmolke, Matthias A1 - Halama, Ralf A1 - Manea, Vlad C. T1 - Slab mantle dehydrates beneath KamchatkaYet recycles water into the deep mantle JF - Geochemistry, geophysics, geosystems N2 - The subduction of hydrated slab mantle is the most important and yet weakly constrained factor in the quantification of the Earth's deep geologic water cycle. The most critical unknowns are the initial hydration state and the dehydration behavior of the subducted oceanic mantle. Here we present a combined thermomechanical, thermodynamic, and geochemical model of the Kamchatka subduction zone that indicates significant dehydration of subducted slab mantle beneath Kamchatka. Evidence for the subduction of hydrated oceanic mantle comes from across-arc trends of boron concentrations and isotopic compositions in arc volcanic rocks. Our thermodynamic-geochemical models successfully predict the complex geochemical patterns and the spatial distribution of arc volcanoes in Kamchatka assuming the subduction of hydrated oceanic mantle. Our results show that water content and dehydration behavior of the slab mantle beneath Kamchatka can be directly linked to compositional features in arc volcanic rocks. Depending on hydration depth of the slab mantle, our models yield water recycling rates between 1.1 × 103 and 7.4 × 103 Tg/Ma/km corresponding to values between 0.75 × 106 and 5.2 × 106 Tg/Ma for the entire Kamchatkan subduction zone. These values are up to one order of magnitude lower than previous estimates for Kamchatka, but clearly show that subducted hydrated slab mantle significantly contributes to the water budget in the Kamchatkan subduction zone. KW - rainfall-runoff KW - scaling KW - heterogeneity in soil hydraulic properties KW - surface sealing KW - run-on KW - patched vegetation cover Y1 - 2016 U6 - https://doi.org/10.1002/2016GC006335 SN - 1525-2027 VL - 17 SP - 2987 EP - 3007 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Wang, Xinxin A1 - Huang, Xianyu A1 - Sachse, Dirk A1 - Hu, Yu A1 - Xue, Jiantao A1 - Meyers, Philip A. T1 - Comparisons of lipid molecular and carbon isotopic compositions in two particle-size fractions from surface peat and their implications for lipid preservation JF - Environmental earth sciences N2 - Knowledge of the possible impacts of early diagenesis on lipid biomarkers in geologic settings is important for robust applications of lipid proxies for paleoclimate reconstructions. In this study, molecular distributions and carbon isotopic compositions of lipids were compared in two particle-size fractions (<0.3 mm and >0.3 mm) of twelve surface peat samples collected from Dajiuhu peatland, central China. The average chain length (ACL) values of long-chain n-alkanes, n-fatty alcohols, n-fatty acids and n-alkan-2-ones show no significant differences between the finer and coarser fractions. In contrast, the carbon preference index values of long-chain n-alkanes, n-fatty alcohols and n-alkan-2-ones have relatively smaller values in the finer fractions than in the coarser ones. Stanols were also more abundant in the finer fractions. In addition, the delta C-13 values of odd-numbered n-alkanes (C-23-C-33) were generally less negative in the finer fractions. Our results indicate that (1) the finer fractions probably experienced stronger degradation than the coarser fractions; (2) the less negative delta(CC)-C-13 values of odd-numbered n-alkanes (C-23-C-33) in the finer fractions were largely a result of greater heterotrophic reworking during degradation; (3) ACL values of long-chain n-alkyl lipids (n-alkanes, n-fatty alcohols and n-fatty acids, n-alkan-2-ones) appear to be reliable proxies to trace lipid sources and their associated paleoenvironmental signals in peat deposits. KW - Peat KW - Lipids KW - Compound-specific carbon isotope KW - Particle-size fractions KW - Decomposition Y1 - 2016 U6 - https://doi.org/10.1007/s12665-016-5960-3 SN - 1866-6280 SN - 1866-6299 VL - 75 SP - 375 EP - 385 PB - Springer CY - New York ER - TY - JOUR A1 - Bora, Sanjay Singh A1 - Scherbaum, Frank A1 - Kuehn, Nicolas A1 - Stafford, Peter T1 - On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs) JF - Bulletin of the Seismological Society of America N2 - The functional form of empirical response spectral ground-motion prediction equations (GMPEs) is often derived using concepts borrowed from Fourier spectral modeling of ground motion. As these GMPEs are subsequently calibrated with empirical observations, this may not appear to pose any major problems in the prediction of ground motion for a particular earthquake scenario. However, the assumption that Fourier spectral concepts persist for response spectra can lead to undesirable consequences when it comes to the adjustment of response spectral GMPEs to represent conditions not covered in the original empirical data set. In this context, a couple of important questions arise, for example, what are the distinctions and/or similarities between Fourier and response spectra of ground motions? And, if they are different, then what is the mechanism responsible for such differences and how do adjustments that are made to Fourier amplitude spectrum (FAS) manifest in response spectra? The present article explores the relationship between the Fourier and response spectrum of ground motion by using random vibration theory (RVT). With a simple Brune (1970, 1971) source model, RVT-generated acceleration spectra for a fixed magnitude and distance scenario are used. The RVT analyses reveal that the scaling of low oscillator-frequency response spectral ordinates can be treated as being equivalent to the scaling of the corresponding Fourier spectral ordinates. However, the high oscillator-frequency response spectral ordinates are controlled by a rather wide band of Fourier spectral ordinates. In fact, the peak ground acceleration, counter to the popular perception that it is a reflection of the high-frequency characteristics of ground motion, is controlled by the entire Fourier spectrum of ground motion. Additionally, this article demonstrates how an adjustment made to FAS is similar or different to the same adjustment made to response spectral ordinates. For this purpose, two cases: adjustments to the stress parameter (Delta sigma) (source term), and adjustments to the attributes reflecting site response (V-S - kappa(0)) are considered. Y1 - 2016 U6 - https://doi.org/10.1785/0120150129 SN - 0037-1106 SN - 1943-3573 VL - 106 SP - 1235 EP - 1253 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Rudaya, Natalia A1 - Nazarova, Larisa B. A1 - Novenko, Elena A1 - Andreev, Andrei A1 - Kalugin, Ivan A1 - Daryin, Andrei A1 - Babich, Valery A1 - Li, Hong-Chun A1 - Shilov, Pavel T1 - Quantitative reconstructions of mid- to late holocene climate and vegetation in the north-eastern altai mountains recorded in lake teletskoye JF - Global and planetary change N2 - We report the first high-resolution (20-50 years) mid- to late Holocene pollen records from Lake Teletskoye, the largest lake in the Altai Mountains, in south-eastern West Siberia. Generally, the mid- to late Holocene (the last 4250 years) vegetation of the north-eastern Altai, as recorded in two studied sediment cores, is characterised by Siberian pine-spruce-fir forests that are similar to those of the present day. A relatively cool and dry interval with July temperatures lower than those of today occurred between 3.9 and 3.6 ka BP. The widespread distribution of open, steppe-like communities with Artemisia, Chenopodiaceae and Cyperaceae reflects maximum deforestation during this interval. After ca. 3.5 ka BP, the coniferous mountain taiga spread significantly, with maximum woody coverage and taiga biome scores between ca. 2.7 and 1.6 ka BP. This coincides well with the highest July temperature (approximately 1 degrees C higher than today) intervals. A short period of cooling about 13-1.4 ka BP could have been triggered by the increased volcanic activity recorded across the Northern Hemisphere. A new period of cooling started around 1100-1150 CE, with the minimum July temperatures occurring between 1450 and 1800 CE. (C) 2016 Elsevier B.V. All rights reserved. KW - Mid-late Holocene KW - Siberia KW - Altai KW - Pollen KW - Climate KW - Vegetation KW - Transfer function KW - Woody coverage Y1 - 2016 U6 - https://doi.org/10.1016/j.gloplacha.2016.04.002 SN - 0921-8181 SN - 1872-6364 VL - 141 SP - 12 EP - 24 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Jambrina-Enriquez, Margarita A1 - Sachse, Dirk A1 - Valero-Garces, Blas L. T1 - A deglaciation and Holocene biomarker-based reconstruction of climate and environmental variability in NW Iberian Peninsula: the Sanabria Lake sequence JF - Journal of paleolimnolog N2 - The molecular biomarker composition of two sediment cores from Sanabria Lake (NW Iberian Peninsula) and a survey of modern plants in the watershed provide a reconstruction of past vegetation and landscape dynamics since deglaciation. During a proglacial stage in Lake Sanabria (prior to 14.7 cal ka BP), very low biomarker concentration and carbon preference index (CPI) values similar to 1 suggest that the n-alkanes could have derived from eroded ancient sediment sources or older organic matter with high degree of maturity. During the Late glacial (14.7-11.7 cal ka BP) and the Holocene (last 11.7 cal ka BP) intervals with higher biomarker and triterpenoid concentrations (high %nC(29) , nC(31) alkanes), higher CPI and average carbon length (ACL), and lower P-aq (proportion of aquatic plants) are indicative of major contribution of vascular land plants from a more forested watershed (e.g. Mid Holocene period 7.0-4.0 cal ka BP). Lower biomarker concentrations (high %nC(27) alkanes), CPI and ACL values responded to short phases with decreased allochthonous contribution into the lake that correspond to centennial-scale periods of regional forest decline (e.g. 4-3 ka BP, Roman deforestation after 2.0 ka, and some phases of the LIA, seventeenth-nineteenth centuries). Human activities in the watershed were significant during early medieval times (1.3-1.0 cal ka BP) and since 1960 CE, in both cases associated with relatively higher productivity stages in the lake (lower biomarker and triterpenoid concentrations, high %nC(23) and %nC(31) respectively, lower ACL and CPI values and higher P-aq). The lipid composition of Sanabria Lake sediments indicates a major allochthonous (watershed-derived) contribution to the organic matter budget since deglaciation, and a dominant oligotrophic status during the lake history. The study constrains the climate and anthropogenic forcings and watershed versus lake sources in organic matter accumulation processes and helps to design conservation and management policies in mountain, oligotrophic lakes. KW - Plant n-alkanes KW - Lipid biomarker KW - Sanabria Lake KW - n-Alkanes KW - Holocene KW - Lateglacial KW - Iberian Peninsula Y1 - 2016 U6 - https://doi.org/10.1007/s10933-016-9890-6 SN - 0921-2728 SN - 1573-0417 VL - 56 SP - 49 EP - 66 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Dietrich, Ottfried A1 - Schweigert, Susanne A1 - Steidl, Jörg A1 - Lischeid, Gunnar T1 - Effects of Data and Model Simplification on the Results of a Wetland Water Resource Management Model JF - Water N2 - This paper presents the development of a wetland water balance model for use in a large river basin with many different wetlands. The basic model was primarily developed for a single wetland with a complex water management system involving large amounts of specialized input data and water management details. The aim was to simplify the model structure and to use only commonly available data as input for the model, with the least possible loss of accuracy. Results from different variants of the model and data adaptation were tested against results from a detailed model. This shows that using commonly available data and unifying and simplifying the input data is tolerable up to a certain level. The simplification of the model has greater effects on the evaluated water balance components than the data adaptation. Because this simplification was necessary for large-scale use, we suggest that, for reasons of comparability, simpler models should always be applied with uniform data bases for large regions, though these should only be moderately simplified. Further, we recommend using these simplified models only for large-scale comparisons and using more specific, detailed models for investigations on smaller scales. KW - wetland KW - water balance KW - water balance model KW - evapotranspiration KW - groundwater level Y1 - 2016 U6 - https://doi.org/10.3390/w8060252 SN - 2073-4441 VL - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Spiekermann, Georg A1 - Wilke, Max A1 - Jahn, Sandro T1 - Structural and dynamical properties of supercritical H2O-SiO2 fluids studied by ab initio molecular dynamics JF - Chemical geology : official journal of the European Association for Geochemistry N2 - In this study we report the structure of supercritical H2O-SiO2 fluid composed of 50 mol% H2O and 50 mol% SiO2 at 3000 K and 2400 K. investigated by means of ab initio molecular dynamics of models comprising 192 and 96 atoms. The density is set constant to 138 g/cm(3), which yields a pressure of 4.3 GPa at 3000 K and 3.6 GPa at 2400 K. Throughout the trajec[ories, water molecules are formed and dissociated via the network modifying reaction 2 SiOH = SiOSi + H2O The calculation of the reaction constant K- [OH](2)/[H2O][O2-] is carried out on the basis of the experimentally relevant Q ' species notation and agrees well with an extrapolation of experimental data to 3000 K. After quench from 3000 K to 2400 K, the degree of polymerization of the silicate network in the 192-atom models increases noticeably within several tens of picoseconds, accompanied by release of molecular H2O. An unexpected opposite trend is observed in smaller 96-atom models, due to a finite size effect, as several uncorrelated models of 192 and 96 atoms indicate. The temperature-dependent slowing down of the H2O-silica interaction dynamics is described on the basis of the bond autocorrelation function. (C) 2016 Elsevier B.V. All rights reserved. KW - Fluid KW - SiO2-H2O KW - SiO(2)Molecular dynamics KW - Polymerization KW - DFT Y1 - 2016 U6 - https://doi.org/10.1016/j.chemgeo.2016.01.010 SN - 0009-2541 SN - 1878-5999 VL - 426 SP - 85 EP - 94 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ramisch, Arne A1 - Lockot, Gregori A1 - Haberzettl, Torsten A1 - Hartmann, Kai A1 - Kuhn, Gerhard A1 - Lehmkuhl, Frank A1 - Schimpf, Stefan A1 - Schulte, Philipp A1 - Stauch, Georg A1 - Wang, Rong A1 - Wunnemann, Bernd A1 - Yan, Dada A1 - Zhang, Yongzhan A1 - Diekmann, Bernhard T1 - A persistent northern boundary of Indian Summer Monsoon precipitation over Central Asia during the Holocene JF - Scientific reports N2 - Extra-tropical circulation systems impede poleward moisture advection by the Indian Summer Monsoon. In this context, the Himalayan range is believed to insulate the south Asian circulation from extra-tropical influences and to delineate the northern extent of the Indian Summer Monsoon in central Asia. Paleoclimatic evidence, however, suggests increased moisture availability in the Early Holocene north of the Himalayan range which is attributed to an intensification of the Indian Summer Monsoon. Nevertheless, mechanisms leading to a surpassing of the Himalayan range and the northern maximum extent of summer monsoonal influence remain unknown. Here we show that the Kunlun barrier on the northern Tibetan Plateau [similar to 36 degrees N] delimits Indian Summer Monsoon precipitation during the Holocene. The presence of the barrier relocates the insulation effect 1,000 km further north, allowing a continental low intensity branch of the Indian Summer Monsoon which is persistent throughout the Holocene. Precipitation intensities at its northern extent seem to be driven by differentiated solar heating of the Northern Hemisphere indicating dependency on energy-gradients rather than absolute radiation intensities. The identified spatial constraints of monsoonal precipitation will facilitate the prediction of future monsoonal precipitation patterns in Central Asia under varying climatic conditions. Y1 - 2016 U6 - https://doi.org/10.1038/srep25791 SN - 2045-2322 VL - 6 SP - 596 EP - 633 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Wendi, Dadiyorto A1 - Liong, Shie-Yui A1 - Sun, Yabin A1 - Doan, Chi Dung T1 - An innovative approach to improve SRTM DEM using multispectral imagery and artificial neural network JF - Journal of advances in modeling earth systems N2 - Although the Shuttle Radar Topography Mission [SRTM) data are a publicly accessible Digital Elevation Model [DEM) provided at no cost, its accuracy especially at forested area is known to be limited with root mean square error (RMSE) of approx. 14 m in Singapore's forested area. Such inaccuracy is attributed to the 5.6 cm wavelength used by SRTM that does not penetrate vegetation well. This paper considers forested areas of central catchment of Singapore as a proof of concept of an approach to improve the SRTM data set. The approach makes full use of (1) the introduction of multispectral imagery (Landsat 8), of 30 m resolution, into SRTM data; (2) the Artificial Neural Network (ANN) to flex its known strengths in pattern recognition and; (3) a reference DEM of high accuracy (1 m) derived through the integration of stereo imaging of worldview-1 and extensive ground survey points. The study shows a series of significant improvements of the SRTM when assessed with the reference DEM of 2 different areas, with RMSE reduction of ∼68% (from 13.9 m to 4.4 m) and ∼52% (from 14.2 m to 6.7 m). In addition, the assessment of the resulting DEM also includes comparisons with simple denoising methodology (Low Pass Filter) and commercially available product called NEXTMap® World 30™. KW - SRTM improvements KW - Landsat 8 KW - ANN Y1 - 2016 U6 - https://doi.org/10.1002/2015MS000536 SN - 1942-2466 VL - 8 SP - 691 EP - 702 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Kalbe, Johannes A1 - Jagher, Reto A1 - Puempin, Christine T1 - The spring of Nadaouiyeh Ain Askar - Paleoecology of a Paleolithic oasis in arid central Syria JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - The site Nadaouiyeh Aïn Askar, an ancient artesian spring near the village of El Kowm, Central Syria, is an example of long lasting human occupation in a desert environment throughout the Middle and Late Pleistocene. The excavations expose a succession of sedimentary units, containing an artifact assemblage assigned to the Acheulean techno-complex. Unit VI, attributed to the Marine Isotope Stage 13, is rich in ostracod valves and was chosen for the present environmental study. From these sediments Heterocypris salina, H. incongruens, Cyprideis torosa, Ilyocypris cf. bradyi, I. inermis, I. cf. gibba, Darwinula stevensoni, Plesiocypridopsis newtoni, Pseudocandona compressa, Candona cf. neglecta, Pseudocandona sp., Trajancypris sp., Physocypria sp. and Mixtacandona sp. are documented for the first time in the Middle Pleistocene of the arid environment of central Syria. Data from these microfossils as well as geochemical proxies implicate three phases, turning the wetland from a palustrine setting into a spring supplied pond with increasing salinity. The high mineralization of the spring waters enables a discussion about early hominin adaptability to brackish waters as drinking water resources, common within the steppe and desert environments along the “out-of-Africa”—corridor in the eastern Mediterranean. KW - Syria KW - Lower Paleolithic KW - Marine Isotope Stage 13 KW - Desert wetland ecosystems KW - Ostracoda KW - Drinking water quality Y1 - 2016 U6 - https://doi.org/10.1016/j.palaeo.2016.01.030 SN - 0031-0182 SN - 1872-616X VL - 446 SP - 252 EP - 262 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Prasad, Sushma A1 - Mishra, Praveen Kumar A1 - Menzel, Philip A1 - Gaye, Birgit A1 - Jehangir, Arshid A1 - Yousuf, Abdul R. T1 - Testing the validity of productivity proxy indicators in high altitude Tso Moriri Lake, NW Himalaya (India) JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - We use multiple proxies (delta C-13(org), delta N-15(org), C/N, amino acids, biogenic silica) from the catchment, lake surface and core sediments to (i) identify the factors influencing conventional lacustrine primary productivity (LPP) indicators (isotopic covariance, C/N) in the sediments from the pristine high altitude Tso Moriri Lake during the late Quaternary, (ii) compare C/N and bulk organic isotopic data from the core with available biogenic silica and amino acid data to test the applicability of conventional LPP indicators during the late Quaternary, and (iii) evaluate the degree of sensitivity of LPP to climate change. Our results show that climate driven changes in water salinity and source water changes have influenced the isotopic (delta C-13, delta N-15) content of the lake water and hence the isotopic composition of bulk organic matter. Erosion has also played a role in masking the LPP as the catchment sediments from this high altitude lake have low C/N thereby casting doubt on the effectiveness of this parameter as an LPP indicator. Independent LPP indicators in Tso Moriri sediments clearly indicate that it is driven by climate change and increases during warmer periods. However, our data show that the LPP in recent times is not much higher than during the early Holocene, ruling out any impact of recent warming on LPP and therefore the possibility of large carbon sequestration in high altitude oligotrophic lakes. (C) 2016 Elsevier B.V. All rights reserved. KW - Tso Moriri Lake KW - isotopes KW - lacustrine primary productivity (LPP) KW - Indian monsoon KW - late Quaternary Y1 - 2016 U6 - https://doi.org/10.1016/j.palaeo.2016.02.027 SN - 0031-0182 SN - 1872-616X VL - 449 SP - 421 EP - 430 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tian, Fang A1 - Cao, Xianyong A1 - Dallmeyer, Anne A1 - Ni, Jian A1 - Zhao, Yan A1 - Wang, Yongbo A1 - Herzschuh, Ulrike T1 - Quantitative woody cover reconstructions from eastern continental Asia of the last 22 kyr reveal strong regional peculiarities JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - We present a calibration-set based on modern pollen and satellite-based Advanced Very High Resolution Radiometer (AVHRR) observations of woody cover (including needleleaved, broadleaved and total tree cover) in eastern continental Asia, which shows good performance under cross-validation with the modern analogue technique (all the coefficients of determination between observed and predicted values are greater than 0.65). The calibration-set is used to reconstruct woody cover from a taxonomically harmonized and temporally standardized fossil pollen dataset (including 274 cores) with 500-year resolution over the last 22 kyr. The spatial range of forest has not noticeably changed in eastern continental Asia during the last 22 kyr, although woody cover has, especially at the margin of the eastern Tibetan Plateau and in the forest-steppe transition area of north-central China. Vegetation was sparse during the LGM in the present forested regions, but woody cover increased markedly at the beginning of the Bolling/Allerod period (B/A; ca. 14.5 ka BP) and again at the beginning of the Holocene (ca. 11.5 ka BP), and is related to the enhanced strength of the East Asian Summer Monsoon. Forest flourished in the mid Holocene (ca. 8 ka BP) possibly due to favourable climatic conditions. In contrast, cover was stable in southern China (high cover) and arid central Asia (very low cover) throughout the investigated period. Forest cover increased in the north-eastern part of China during the Holocene. Comparisons of these regional pollen-based results with simulated forest cover from runs of a global climate model (for 9, 6 and 0 ka BP (ECHAM5/JSBACH similar to 1.125 degrees spatial resolution)) reveal many similarities in temporal change. The Holocene woody cover history of eastern continental Asia is different from that of other regions, likely controlled by different climatic variables, i.e. moisture in eastern continental Asia; temperature in northern Eurasia and North America. (C) 2016 Elsevier Ltd. All rights reserved. KW - Pollen KW - AVHRR KW - Modern analogue technique KW - Quantitative reconstruction KW - East Asian summer monsoon Y1 - 2016 U6 - https://doi.org/10.1016/j.quascirev.2016.02.001 SN - 0277-3791 VL - 137 SP - 33 EP - 44 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Ramos, C. A1 - Mechie, James A1 - Feng, M. T1 - Shear wave velocity and Poisson's ratio models across the southern Chile convergent margin at 38°15′S JF - Geophysical journal international N2 - Using active and passive seismology data we derive a shear (S) wave velocity model and a Poisson's ratio (σ) model across the Chilean convergent margin along a profile at 38°15′S, where the Mw 9.5 Valdivia earthquake occurred in 1960. The derived S-wave velocity model was constructed using three independently obtained velocity models that were merged together. In the upper part of the profile (0–2 km depth), controlled source data from explosions were used to obtain an S-wave traveltime tomogram. For the middle part (2–20 km depth), data from a temporary seismology array were used to carry out a dispersion analysis. The resulting dispersion curves were used to obtain a 3-D S-wave velocity model. In the lower part (20–75 km depth, depending on the longitude), an already existent local earthquake tomographic image was merged with the other two sections. This final S-wave velocity model and already existent compressional (P) wave velocity models along the same transect allowed us to obtain a Poisson's ratio model. The results of this study show that the velocities and Poisson's ratios in the continental crust of this part of the Chilean convergent margin are in agreement with geological features inferred from other studies and can be explained in terms of normal rock types. There is no requirement to call on the existence of measurable amounts of present-day fluids, in terms of seismic velocities, above the plate interface in the continental crust of the Coastal Cordillera and the Central Valley in this part of the Chilean convergent margin. This is in agreement with a recent model of water being transported down and released from the subduction zone. KW - Controlled source seismology KW - Seismic tomography KW - Computational seismology KW - South America Y1 - 2016 U6 - https://doi.org/10.1093/gji/ggv541 SN - 0956-540X SN - 1365-246X VL - 204 SP - 1620 EP - 1635 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Nabhan, Sami A1 - Luber, Tim A1 - Scheffler, Franziska A1 - Heubeck, Christoph T1 - Climatic and geochemical implications of Archean pedogenic gypsum in the Moodies Group (similar to 3.2 Ga), Barberton Greenstone Belt, South Africa JF - Precambrian research N2 - Lithic sandstones of braided-fluvial to supratidal facies in the Paleoarchean Moodies Group (similar to 3.22 Ga, Barberton Greenstone Belt, South Africa) include several regionally traceable units with common to abundant, in places rock-forming, nodular concretions of megaquartz pseudomorphs after gypsum, barite and calcite. Concretionary accumulations are stratiform and commonly associated with aqueously reworked, fine-grained, tuffaceous sediment of originally rhyodacitic composition and can grow to fist sized agglomerates in crusts tens of m in lateral extent. Weathering of tuffaceous material and feldspar delivered alkali cations such as Ca, Ba, and K, while carbonates were likely supplied by silicate weathering of mafic to ultramafic volcanic rocks during exposure to a CO2-rich atmosphere. Sulfate ions were partly delivered by oxidative pyrite dissolution which may have included microbial and abiotic disproportionation of volcanic S or SO2. Concretionary growth apparently took place under pedogenic to early diagenetic conditions within unconsolidated granular sediment in the vadose zone, dominated by seasonal fluctuations of the groundwater level under evaporitic conditions. The concretions likely represent the oldest terrestrial evaporites known to date and form part of the oldest known compound paleosols. Their formation and composition constrain the local occurrence of sulfate in the Archean atmo- and hydrosphere, their interaction with the emerging biosphere, Archean weathering regime, local climate, and vadose-zone hydrodynamics. (C) 2016 Elsevier B.V. All rights reserved. KW - Barberton Greenstone Belt KW - Archean KW - Moodies Group KW - Evaporites KW - Sulfate KW - Paleosol Y1 - 2016 U6 - https://doi.org/10.1016/j.precamres.2016.01.011 SN - 0301-9268 SN - 1872-7433 VL - 275 SP - 119 EP - 134 PB - Elsevier CY - Amsterdam ER -