TY - JOUR A1 - Smith, Taylor A1 - Zotta, Ruxandra-Maria A1 - Boulton, Chris A. A1 - Lenton, Timothy M. A1 - Dorigo, Wouter A1 - Boers, Niklas T1 - Reliability of resilience estimation based on multi-instrument time series JF - Earth System Dynamics N2 - Many widely used observational data sets are comprised of several overlapping instrument records. While data inter-calibration techniques often yield continuous and reliable data for trend analysis, less attention is generally paid to maintaining higher-order statistics such as variance and autocorrelation. A growing body of work uses these metrics to quantify the stability or resilience of a system under study and potentially to anticipate an approaching critical transition in the system. Exploring the degree to which changes in resilience indicators such as the variance or autocorrelation can be attributed to non-stationary characteristics of the measurement process – rather than actual changes in the dynamical properties of the system – is important in this context. In this work we use both synthetic and empirical data to explore how changes in the noise structure of a data set are propagated into the commonly used resilience metrics lag-one autocorrelation and variance. We focus on examples from remotely sensed vegetation indicators such as vegetation optical depth and the normalized difference vegetation index from different satellite sources. We find that time series resulting from mixing signals from sensors with varied uncertainties and covering overlapping time spans can lead to biases in inferred resilience changes. These biases are typically more pronounced when resilience metrics are aggregated (for example, by land-cover type or region), whereas estimates for individual time series remain reliable at reasonable sensor signal-to-noise ratios. Our work provides guidelines for the treatment and aggregation of multi-instrument data in studies of critical transitions and resilience. Y1 - 2023 U6 - https://doi.org/10.5194/esd-14-173-2023 SN - 2190-4987 VL - 14 SP - 173 EP - 183 PB - Copernicus Publications CY - Göttingen ER - TY - JOUR A1 - Zali, Zahra A1 - Rein, Teresa A1 - Krüger, Frank A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank T1 - Ocean bottom seismometer (OBS) noise reduction from horizontal and vertical components using harmonic–percussive separation algorithms JF - Solid earth N2 - Records from ocean bottom seismometers (OBSs) are highly contaminated by noise, which is much stronger compared to data from most land stations, especially on the horizontal components. As a consequence, the high energy of the oceanic noise at frequencies below 1 Hz considerably complicates the analysis of the teleseismic earthquake signals recorded by OBSs. Previous studies suggested different approaches to remove low-frequency noises from OBS recordings but mainly focused on the vertical component. The records of horizontal components, which are crucial for the application of many methods in passive seismological analysis of body and surface waves, could not be much improved in the teleseismic frequency band. Here we introduce a noise reduction method, which is derived from the harmonic–percussive separation algorithms used in Zali et al. (2021), in order to separate long-lasting narrowband signals from broadband transients in the OBS signal. This leads to significant noise reduction of OBS records on both the vertical and horizontal components and increases the earthquake signal-to-noise ratio (SNR) without distortion of the broadband earthquake waveforms. This is demonstrated through tests with synthetic data. Both SNR and cross-correlation coefficients showed significant improvements for different realistic noise realizations. The application of denoised signals in surface wave analysis and receiver functions is discussed through tests with synthetic and real data. Y1 - 2023 U6 - https://doi.org/10.5194/se-14-181-2023 SN - 1869-9529 VL - 14 IS - 2 SP - 181 EP - 195 PB - Coepernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Bhattacharyya, Biswajit A1 - Balischewski, Christian A1 - Sperlich, Eric A1 - Günter, Christina A1 - Mies, Stefan A1 - Kelling, Alexandra A1 - Taubert, Andreas T1 - N-Butyl Pyridinium Diiodido Argentate(I) BT - A One-Dimensional Ag-I Network with Superior Solid-State Ionic Conductivity at Room Temperature JF - Advanced materials interfaces N2 - A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications. KW - AgI KW - ionic conductivity KW - Ionic liquids KW - thermal properties Y1 - 2023 U6 - https://doi.org/10.1002/admi.202202363 SN - 2196-7350 VL - 10 IS - 12 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Krassakis, Pavlos A1 - Karavias, Andreas A1 - Zygouri, Evangelia A1 - Roumpos, Christos A1 - Louloudis, Georgios A1 - Pyrgaki, Konstantina A1 - Koukouzas, Nikolaos A1 - Kempka, Thomas A1 - Karapanos, Dimitris T1 - GIS-based assessment of hybrid pumped hydro storage as a potential solution for the clean energy transition BT - the case of the Kardia lignite mine, Western Greece JF - Sensors N2 - Planned decommissioning of coal-fired plants in Europe requires innovative technical and economic strategies to support coal regions on their path towards a climate-resilient future. The repurposing of open pit mines into hybrid pumped hydro power storage (HPHS) of excess energy from the electric grid, and renewable sources will contribute to the EU Green Deal, increase the economic value, stabilize the regional job market and contribute to the EU energy supply security. This study aims to present a preliminary phase of a geospatial workflow used to evaluate land suitability by implementing a multi-criteria decision making (MCDM) technique with an advanced geographic information system (GIS) in the context of an interdisciplinary feasibility study on HPHS in the Kardia lignite open pit mine (Western Macedonia, Greece). The introduced geospatial analysis is based on the utilization of the constraints and ranking criteria within the boundaries of the abandoned mine regarding specific topographic and proximity criteria. The applied criteria were selected from the literature, while for their weights, the experts' judgement was introduced by implementing the analytic hierarchy process (AHP), in the framework of the ATLANTIS research program. According to the results, seven regions were recognized as suitable, with a potential energy storage capacity from 1.09 to 5.16 GWh. Particularly, the present study's results reveal that 9.27% (212,884 m(2)) of the area had a very low suitability, 15.83% (363,599 m(2)) had a low suitability, 23.99% (550,998 m(2)) had a moderate suitability, 24.99% (573,813 m(2)) had a high suitability, and 25.92% (595,125 m(2)) had a very high suitability for the construction of the upper reservoir. The proposed semi-automatic geospatial workflow introduces an innovative tool that can be applied to open pit mines globally to identify the optimum design for an HPHS system depending on the existing lower reservoir. KW - hybrid pumped hydro power storage KW - hydro power KW - hydro storage KW - GIS KW - Kardia mine KW - AHP KW - MCDM Y1 - 2023 U6 - https://doi.org/10.3390/s23020593 SN - 1424-8220 VL - 23 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schmidt, Lena Katharina A1 - Francke, Till A1 - Grosse, Peter Martin A1 - Mayer, Christoph A1 - Bronstert, Axel T1 - Reconstructing five decades of sediment export from two glacierized high-alpine catchments in Tyrol, Austria, using nonparametric regression JF - Hydrology and earth system sciences : HESS N2 - Knowledge on the response of sediment export to recent climate change in glacierized areas in the European Alps is limited, primarily because long-term records of suspended sediment concentrations (SSCs) are scarce. Here we tested the estimation of sediment export of the past five decades using quantile regression forest (QRF), a nonparametric, multivariate regression based on random forest. The regression builds on short-term records of SSCs and long records of the most important hydroclimatic drivers (discharge, precipitation and air temperature - QPT). We trained independent models for two nested and partially glacier-covered catchments, Vent (98 km(2)) and Vernagt (11.4 km(2)), in the upper otztal in Tyrol, Austria (1891 to 3772 m a.s.l.), where available QPT records start in 1967 and 1975. To assess temporal extrapolation ability, we used two 2-year SSC datasets at gauge Vernagt, which are almost 20 years apart, for a validation. For Vent, we performed a five-fold cross-validation on the 15 years of SSC measurements. Further, we quantified the number of days where predictors exceeded the range represented in the training dataset, as the inability to extrapolate beyond this range is a known limitation of QRF. Finally, we compared QRF performance to sediment rating curves (SRCs). We analyzed the modeled sediment export time series, the predictors and glacier mass balance data for trends (Mann-Kendall test and Sen's slope estimator) and step-like changes (using the widely applied Pettitt test and a complementary Bayesian approach).Our validation at gauge Vernagt demonstrated that QRF performs well in estimating past daily sediment export (Nash-Sutcliffe efficiency (NSE) of 0.73) and satisfactorily for SSCs (NSE of 0.51), despite the small training dataset. The temporal extrapolation ability of QRF was superior to SRCs, especially in periods with high-SSC events, which demonstrated the ability of QRF to model threshold effects. Days with high SSCs tended to be underestimated, but the effect on annual yields was small. Days with predictor exceedances were rare, indicating a good representativity of the training dataset. Finally, the QRF reconstruction models outperformed SRCs by about 20 percent points of the explained variance.Significant positive trends in the reconstructed annual suspended sediment yields were found at both gauges, with distinct step-like increases around 1981. This was linked to increased glacier melt, which became apparent through step-like increases in discharge at both gauges as well as change points in mass balances of the two largest glaciers in the Vent catchment. We identified exceptionally high July temperatures in 1982 and 1983 as a likely cause. In contrast, we did not find coinciding change points in precipitation. Opposing trends at the two gauges after 1981 suggest different timings of "peak sediment". We conclude that, given large-enough training datasets, the presented QRF approach is a promising tool with the ability to deepen our understanding of the response of high-alpine areas to decadal climate change. Y1 - 2023 U6 - https://doi.org/10.5194/hess-27-1841-2023 SN - 1027-5606 SN - 1607-7938 VL - 27 IS - 9 SP - 1841 EP - 1863 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Timmerman, Martin Jan A1 - Krmicek, Lukas A1 - Krmíčková, Simona A1 - Slama, Jiri A1 - Sudo, Masafumi A1 - Sobel, Edward T1 - Tonian-Ediacaran evolution of the Brunovistulian microcontinent (Czech Republic) deciphered from LA-ICP-MS U-Pb zircon and 40Ar/39Ar muscovite ages JF - Precambrian research N2 - Granitoids of the Slavkov Domain of the Brunovistulian microcontinent (BVM) in the Czech Republic have Ediacaran U-Pb zircon crystallization ages with the dominant magmatic activity occurring between ca. 597 and 595 Ma. The ages overlap published ages for the adjacent Thaya Domain, showing that both domains formed coevally in the same subduction setting. The data support published models in which the Slavkov Domain formed as arc crust. The main stage of magmatism stopped after ca. 595-590 Ma and was quickly followed by cooling accompanied by intrusion of small volumes of rhyolite dykes at ca. 594 Ma. Slavkov Domain metasedimentary rocks are dominated by Cryogenian-Ediacaran detrital zircon populations and their protoliths were locally derived erosional products of Cryogenian to Ediacaran arc rocks of the Thaya and Slavkov domains. Metasedi-mentary rocks from the NE part of the BVM contain younger, ca. 550 Ma zircons indicating that the BVM grew northeastward by accretion of progressively younger material derived from magmatic rocks with latest Ediacaran crystallization ages. In contrast to the Thaya and Slavkov domains, the Metavolcanic Zone that lies between them formed between ca. 740 and 725 Ma in the late Tonian to early Cryogenian. It predates the main stage magmatic activity in the BVM by 135 to 150 Ma and is probably a relic of older crust that formed during rifting of the Rodinia supercontinent. At ca. 552-551 Ma in the latest Ediacaran, parts of the BVM were exposed at the surface, during which time red, terrestrial siliciclastic sediments (Basal Clastics) were deposited. These largely had (very) proximal sources such as the main stage granitoids of the Thaya and Slavkov domains. Clasts of (meta)sandstones contain much older zircon populations and provide evidence that Neoarchaean and Palaeo-, meso- and early Neoproterozoic crustal rocks were exposed in erosional position nearby. KW - Brunovistulicum KW - Cryogenian KW - Ediacaran KW - Basal Clastics KW - U -Pb dating KW - Ar KW - Ar dating Y1 - 2023 U6 - https://doi.org/10.1016/j.precamres.2023.106981 SN - 0301-9268 SN - 1872-7433 VL - 387 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Stoltnow, Malte A1 - Weis, Philipp A1 - Korges, Maximilian T1 - Hydrological controls on base metal precipitation and zoning at the porphyry-epithermal transition constrained by numerical modeling JF - Scientific reports N2 - Ore precipitation in porphyry copper systems is generally characterized by metal zoning (Cu-Mo to Zn-Pb-Ag), which is suggested to be variably related to solubility decreases during fluid cooling, fluid-rock interactions, partitioning during fluid phase separation and mixing with external fluids. Here, we present new advances of a numerical process model by considering published constraints on the temperature- and salinity-dependent solubility of Cu, Pb and Zn in the ore fluid. We quantitatively investigate the roles of vapor-brine separation, halite saturation, initial metal contents, fluid mixing and remobilization as first-order controls of the physical hydrology on ore formation. The results show that the magmatic vapor and brine phases ascend with different residence times but as miscible fluid mixtures, with salinity increases generating metal-undersaturated bulk fluids. The release rates of magmatic fluids affect the location of the thermohaline fronts, leading to contrasting mechanisms for ore precipitation: higher rates result in halite saturation without significant metal zoning, lower rates produce zoned ore shells due to mixing with meteoric water. Varying metal contents can affect the order of the final metal precipitation sequence. Redissolution of precipitated metals results in zoned ore shell patterns in more peripheral locations and also decouples halite saturation from ore precipitation. Y1 - 2023 U6 - https://doi.org/10.1038/s41598-023-30572-5 SN - 2045-2322 VL - 13 IS - 1 PB - Springer Nature CY - London ER - TY - JOUR A1 - Sharma, Shubham A1 - Hainzl, Sebastian A1 - Zöller, Gert T1 - Seismicity parameters dependence on main shock-induced co-seismic stress JF - Geophysical journal international N2 - The Gutenberg-Richter (GR) and the Omori-Utsu (OU) law describe the earthquakes' energy release and temporal clustering and are thus of great importance for seismic hazard assessment. Motivated by experimental results, which indicate stress-dependent parameters, we consider a combined global data set of 127 main shock-aftershock sequences and perform a systematic study of the relationship between main shock-induced stress changes and associated seismicity patterns. For this purpose, we calculate space-dependent Coulomb Stress (& UDelta;CFS) and alternative receiver-independent stress metrics in the surrounding of the main shocks. Our results indicate a clear positive correlation between the GR b-value and the induced stress, contrasting expectations from laboratory experiments and suggesting a crucial role of structural heterogeneity and strength variations. Furthermore, we demonstrate that the aftershock productivity increases nonlinearly with stress, while the OU parameters c and p systematically decrease for increasing stress changes. Our partly unexpected findings can have an important impact on future estimations of the aftershock hazard. KW - earthquake hazards KW - earthquake interaction KW - forecasting and prediction KW - statistical seismology KW - b-value Y1 - 2023 U6 - https://doi.org/10.1093/gji/ggad201 SN - 0956-540X SN - 1365-246X VL - 235 IS - 1 SP - 509 EP - 517 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Bereswill, Sarah A1 - Gatz-Miller, Hannah A1 - Su, Danyang A1 - Tötzke, Christian A1 - Kardjilov, Nikolay A1 - Oswald, Sascha A1 - Mayer, Klaus Ulrich T1 - Coupling non-invasive imaging and reactive transport modeling to investigate water and oxygen dynamics in the root zone JF - Vadose zone journal N2 - Oxygen (O-2) availability in soils is vital for plant growth and productivity. The transport and consumption of O-2 in the root zone is closely linked to soil moisture content, the spatial distribution of roots, as well as structure and heterogeneity of the surrounding soil. In this study, we measure three-dimensional root system architecture and the spatiotemporal dynamics of soil moisture (& theta;) and O-2 concentrations in the root zone of maize (Zea mays) via non-invasive imaging, and then construct and parameterize a reactive transport model based on the experimental data. The combination of three non-invasive imaging methods allowed for a direct comparison of simulation results with observations at high spatial and temporal resolution. In three different modeling scenarios, we investigated how the results obtained for different levels of conceptual complexity in the model were able to match measured & theta; and O-2 concentration patterns. We found that the modeling scenario that considers heterogeneous soil structure and spatial variability of hydraulic parameters (permeability, porosity, and van Genuchten & alpha; and n), better reproduced the measured & theta; and O-2 patterns relative to a simple model with a homogenous soil domain. The results from our combined imaging and modeling analysis reveal that experimental O-2 and water dynamics can be reproduced quantitatively in a reactive transport model, and that O-2 and water dynamics are best characterized when conditions unique to the specific system beyond the distribution of roots, such as soil structure and its effect on water saturation and macroscopic gas transport pathways, are considered. Y1 - 2023 U6 - https://doi.org/10.1002/vzj2.20268 SN - 1539-1663 VL - 22 IS - 5 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Smith, Taylor A1 - Boers, Niklas T1 - Global vegetation resilience linked to water availability and variability JF - Nature Communications N2 - Quantifying the resilience of vegetated ecosystems is key to constraining both present-day and future global impacts of anthropogenic climate change. Here we apply both empirical and theoretical resilience metrics to remotely-sensed vegetation data in order to examine the role of water availability and variability in controlling vegetation resilience at the global scale. We find a concise global relationship where vegetation resilience is greater in regions with higher water availability. We also reveal that resilience is lower in regions with more pronounced inter-annual precipitation variability, but find less concise relationships between vegetation resilience and intra-annual precipitation variability. Our results thus imply that the resilience of vegetation responds differently to water deficits at varying time scales. In view of projected increases in precipitation variability, our findings highlight the risk of ecosystem degradation under ongoing climate change. Vegetation dynamics depend on both the amount of precipitation and its variability over time. Here, the authors show that vegetation resilience is greater where water availability is higher and where precipitation is more stable from year to year. Y1 - 2023 U6 - https://doi.org/10.1038/s41467-023-36207-7 SN - 2041-1723 VL - 14 IS - 1 PB - Springer Nature CY - London ER -