TY - JOUR A1 - Vogt-Vincent, Noam A1 - Lippold, Jörg A1 - Kaboth-Bahr, Stefanie A1 - Blaser, Patrick T1 - Ice-rafted debris as a source of non-conservative behaviour for the epsilon Nd palaeotracer BT - insights from a simple model JF - Geo-marine letters : an international journal of marine geology N2 - Neodymium isotopic composition (epsilon Nd) has enjoyed widespread use as a palaeotracer, principally because it behaves quasi-conservatively in the modern ocean. However, recent bottom water epsilon Nd reconstructions from the eastern North Atlantic are difficult to interpret under assumptions of conservative behaviour. The observation that this apparent departure from conservative behaviour increases with enhanced ice-rafted debris (IRD) fluxes has resulted in the suggestion that IRD leads to the overprinting of bottom water epsilon Nd through reversible scavenging. In this study, a simple water column model successfully reproduces epsilon Nd reconstructions from the eastern North Atlantic at the Last Glacial Maximum and Heinrich Stadial 1, and demonstrates that the changes in scavenging intensity required for good model-data fit is in good agreement with changes in the observed IRD flux. Although uncertainties in model parameters preclude a more definitive conclusion, the results indicate that the suggestion of IRD as a source of non-conservative behaviour in the epsilon Nd tracer is reasonable and that further research into the fundamental chemistry underlying the marine neodymium cycle is necessary to increase confidence in assumptions of conservative epsilon Nd behaviour in the past. KW - Neodymium isotopes KW - epsilon Nd KW - ice-rafted debris KW - IRD KW - last glacial KW - maximum KW - LGM KW - Heinrich event KW - Palaeoceanography KW - Paleoceanography KW - model KW - reversible scavenging KW - conservative KW - ocean circulation KW - atlantic KW - meridional overturning circulation KW - geochemical cycling Y1 - 2020 U6 - https://doi.org/10.1007/s00367-020-00643-x SN - 0276-0460 SN - 1432-1157 VL - 40 IS - 3 SP - 325 EP - 340 PB - Springer CY - Berlin ER - TY - GEN A1 - Smirnov, Artem G. A1 - Kronberg, Elena A. A1 - Daly, Patrick W. A1 - Aseev, Nikita A1 - Shprits, Yuri Y. A1 - Kellerman, Adam C. T1 - Adiabatic Invariants Calculations for Cluster Mission: A Long-Term Product for Radiation Belts Studies T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The Cluster mission has produced a large data set of electron flux measurements in the Earth's magnetosphere since its launch in late 2000. Electron fluxes are measured using Research with Adaptive Particle Imaging Detector (RAPID)/Imaging Electron Spectrometer (IES) detector as a function of energy, pitch angle, spacecraft position, and time. However, no adiabatic invariants have been calculated for Cluster so far. In this paper we present a step-by-step guide to calculations of adiabatic invariants and conversion of the electron flux to phase space density (PSD) in these coordinates. The electron flux is measured in two RAPID/IES energy channels providing pitch angle distribution at energies 39.2-50.5 and 68.1-94.5 keV in nominal mode since 2004. A fitting method allows to expand the conversion of the differential fluxes to the range from 40 to 150 keV. Best data coverage for phase space density in adiabatic invariant coordinates can be obtained for values of second adiabatic invariant, K, similar to 10(2), and values of the first adiabatic invariant mu in the range approximate to 5-20 MeV/G. Furthermore, we describe the production of a new data product "LSTAR," equivalent to the third adiabatic invariant, available through the Cluster Science Archive for years 2001-2018 with 1-min resolution. The produced data set adds to the availability of observations in Earth's radiation belts region and can be used for long-term statistical purposes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1192 KW - L-Asterisk KW - magnetosphere KW - electrons KW - model Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-523915 SN - 1866-8372 IS - 2 ER - TY - JOUR A1 - Smirnov, Artem G. A1 - Kronberg, Elena A. A1 - Daly, Patrick W. A1 - Aseev, Nikita A1 - Shprits, Yuri Y. A1 - Kellerman, Adam C. T1 - Adiabatic Invariants Calculations for Cluster Mission: A Long-Term Product for Radiation Belts Studies JF - Journal of Geophysical Research: Space Physics N2 - The Cluster mission has produced a large data set of electron flux measurements in the Earth's magnetosphere since its launch in late 2000. Electron fluxes are measured using Research with Adaptive Particle Imaging Detector (RAPID)/Imaging Electron Spectrometer (IES) detector as a function of energy, pitch angle, spacecraft position, and time. However, no adiabatic invariants have been calculated for Cluster so far. In this paper we present a step-by-step guide to calculations of adiabatic invariants and conversion of the electron flux to phase space density (PSD) in these coordinates. The electron flux is measured in two RAPID/IES energy channels providing pitch angle distribution at energies 39.2-50.5 and 68.1-94.5 keV in nominal mode since 2004. A fitting method allows to expand the conversion of the differential fluxes to the range from 40 to 150 keV. Best data coverage for phase space density in adiabatic invariant coordinates can be obtained for values of second adiabatic invariant, K, similar to 10(2), and values of the first adiabatic invariant mu in the range approximate to 5-20 MeV/G. Furthermore, we describe the production of a new data product "LSTAR," equivalent to the third adiabatic invariant, available through the Cluster Science Archive for years 2001-2018 with 1-min resolution. The produced data set adds to the availability of observations in Earth's radiation belts region and can be used for long-term statistical purposes. KW - L-Asterisk KW - magnetosphere KW - electrons KW - model Y1 - 2019 VL - 125 IS - 2 PB - John Wiley & Sons, Inc. CY - New Jersey ER - TY - GEN A1 - Pauly, Maren A1 - Helle, Gerhard A1 - Miramont, Cécile A1 - Büntgen, Ulf A1 - Treydte, Kerstin A1 - Reinig, Frederick A1 - Guibal, Frédéric A1 - Sivan, Olivier A1 - Heinrich, Ingo A1 - Riedel, Frank A1 - Kromer, Bernd A1 - Balanzategui, Daniel A1 - Wacker, Lukas A1 - Sookdeo, Adam Sookdeo A1 - Brauer, Achim T1 - Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (delta O-18, delta C-13) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (delta O-18(sw)) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (delta O-18(sw)), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low delta O-18(sw)) versus Mediterranean (high delta O-18(sw)) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1135 KW - annually laminated sediments KW - lake Meerfelder Maar KW - isotopic composition KW - oxygen isotope KW - climate KW - cellulose KW - radiocarbon KW - temperature KW - record KW - model Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459169 SN - 1866-8372 IS - 1135 ER - TY - JOUR A1 - Kumar, Rohini A1 - Hesse, Fabienne A1 - Rao, P. Srinivasa A1 - Musolff, Andreas A1 - Jawitz, James A1 - Sarrazin, Francois A1 - Samaniego, Luis A1 - Fleckenstein, Jan H. A1 - Rakovec, Oldrich A1 - Thober, S. A1 - Attinger, Sabine T1 - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe JF - Nature Communications N2 - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes. KW - travel time distributions KW - groundwater vulnerability KW - flux tracking KW - transit-time KW - water age KW - nitrogen KW - model KW - dynamics KW - pollution KW - patterns Y1 - 2020 U6 - https://doi.org/10.1038/s41467-020-19955-8 SN - 2041-1723 VL - 11 IS - 1 SP - 1 EP - 10 PB - Nature Publishing Group UK CY - London ER - TY - GEN A1 - Kumar, Rohini A1 - Hesse, Fabienne A1 - Rao, P. Srinivasa A1 - Musolff, Andreas A1 - Jawitz, James A1 - Sarrazin, Francois A1 - Samaniego, Luis A1 - Fleckenstein, Jan H. A1 - Rakovec, Oldrich A1 - Thober, S. A1 - Attinger, Sabine T1 - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1352 KW - travel time distributions KW - groundwater vulnerability KW - flux tracking KW - transit-time KW - water age KW - nitrogen KW - model KW - dynamics KW - pollution KW - patterns Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549875 SN - 1866-8372 IS - 1 ER - TY - JOUR A1 - Böhnke, Denise A1 - Krehl, Alice A1 - Moermann, Kai A1 - Volk, Rebekka A1 - Lützkendorf, Thomas A1 - Naber, Elias A1 - Becker, Ronja A1 - Norra, Stefan T1 - Mapping urban green and its ecosystem services at microscale-a methodological approach for climate adaptation and biodiversity JF - Sustainability / Multidisciplinary Digital Publishing Institute (MDPI) N2 - The current awareness of the high importance of urban green leads to a stronger need for tools to comprehensively represent urban green and its benefits. A common scientific approach is the development of urban ecosystem services (UES) based on remote sensing methods at the city or district level. Urban planning, however, requires fine-grained data that match local management practices. Hence, this study linked local biotope and tree mapping methods to the concept of ecosystem services. The methodology was tested in an inner-city district in SW Germany, comparing publicly accessible areas and non-accessible courtyards. The results provide area-specific [m(2)] information on the green inventory at the microscale, whereas derived stock and UES indicators form the basis for comparative analyses regarding climate adaptation and biodiversity. In the case study, there are ten times more micro-scale green spaces in private courtyards than in the public space, as well as twice as many trees. The approach transfers a scientific concept into municipal planning practice, enables the quantitative assessment of urban green at the microscale and illustrates the importance for green stock data in private areas to enhance decision support in urban development. Different aspects concerning data collection and data availability are critically discussed. KW - climate adaptation KW - urban green KW - mapping KW - ecosystem service cascade KW - model KW - surface type-function-concept KW - planning indicators KW - city district KW - level KW - urban planning practice KW - climate change Y1 - 2022 U6 - https://doi.org/10.3390/su14159029 SN - 2071-1050 VL - 14 IS - 15 PB - MDPI CY - Basel ER -