bluuebunny/crossref_metadata_2025 huggingface dataset:
Sampling the SML for traces gases: a case study of sampling technique and resulting correction factors
Authors: Lange Lea , Booge Dennis , Karnatz Josefine , Bange Hermann , Marandino Christa
Published: March 2024

The sea surface microlayer (SML) is the uppermost thin oceanic surface layer in the range of 100µm with properties that are distinct from the water below. With an ocean coverage of up to 70% it is supposed to have a significant impact on air-sea gas exchange rates. In global studies, the SML is often supposed to be a missing source of trace gases, when oceanic production and the subsequent emissions alone cannot explain observed atmospheric mixing ratios. Despite the attention in the past 20 years, also in the SOLAS science plan, it remains difficult to sample volatile trace gases from the SML with existing sampling techniques. Consequently, an incomplete process understanding of trace gas cycling within the SML inhibits its effect on air-sea gas exchange.In this study, we focus on existing and common SML sampling methods (glass plate, Garrett screen) in order to ensure that trace gas samples are comparable to other parameters sampled with the same method. A series of laboratory experiments was set up to determine a correction factor which quantifies the loss of trace gases due to the sampling method itself. Dimethyl sulfide, isoprene and carbon disulfide were sampled with a glass plate and with a Garrett screen under varying surfactant concentrations and environmental conditions (salinity, temperature). Based on physiochemical properties of the examined trace gases, we extended the correction factor to nitrous oxide and methane. Losses are high, but not as variable as expected. Around 90% are lost due to sampling with small variations between different gases. The presence of surfactants has a small effect on the losses.The lab-based correction factors are applied to in-field SML samples from a mesocosm study in May/June 2023 conducted within the DFG research unit BASS. Those results clearly indicate that the composition of the SML highly influences the correction factor for each trace gas individually. Comparing corrected SML concentrations with underlying bulk water concentrations reveal the accumulation of specific traces gases in the SML which highly influence the magnitude of trace gas emissions to the atmosphere.
Eutrophication and phosphorus release of rewetted peatlands - lesson learned from Neman River basin
Authors: Banaszuk Piotr , Kamocki Andrzej , Grygoruk Mateusz , Manton Michael , Wichtmann Wendelin
Published: March 2024

Rewetting peatlands and restoring wetland buffer zones are often considered primary measures to support local biodiversity and mitigate non-point agricultural pollution loads. However, rewetting peat soils (histosols) that were previously used for agriculture, intensive grasslands, or croplands could lead to the release of soil phosphorus and cause eutrophication of soil, groundwater, and adjacent watercourses (Smolders et al., 2006; Banaszuk et al., 2011). Estimates suggest that phosphorus concentration in soil pore water of rewetted fen can be up to three orders of magnitude higher than under natural conditions (Zak et al., 2008).Under the framework of the Interreg Baltic Sea region project "DESIRE", we estimated the total phosphorus (TP) accumulation within the topsoil (up to 50 cm in depth) in four peatlands planned for restoration in three countries (Lithuania, Poland, Russia - Kaliningrad Region) of the Neman River basin.Results show that the long-term agricultural use of histosols may result in total phosphorus accumulation in the topsoil, ranging from 50 to over 300 g P m2. A significant part of P consists of metal oxide compounds as redox-sensitive phosphorus characterized by variable dynamics. Soil anoxia increases after rewetting, causing reductive Fe (III) compounds to dissolve, leading to a high discharge rate of Fe (II) and P. Therefore, a significant P release is expected, which can amount to up to 6 g P m2 (NH4Cl_P + BD_P fractions), followed by severe ground- and surface water pollution.The initial influx of nutrients after rewetting can be significant, and affect the expected restoration outcome (Cabezas et al., 2013). Eutrophication can support the spread of fast-growing generalist plant species, mainly Phragmites australis and Typha sp., instead of the diverse vegetation composition targeted by restoration planners (Kreyling et al., 2021). Nonetheless, these new rewetted ecosystems may provide some services comparable to pristine wetlands, and the export of nutrients by regular harvesting under paludiculture management reduces the risk of nutrient losses to open waters.In conclusion, elevated release of P is initially expected for nutrient-rich rewetted histosols. Nevertheless, in the long run the benefits from rewetting outweigh the disservices of draining peatlands. 
Marine munition in coastal seas: High-resolution numerical simulations of munition-related contaminants
Authors: Chrysagi Evridiki , Gräwe Ulf
Published: March 2024

After the Second World War, vast quantities of munitions were dumped in the world’s oceans. Over the years, the metal casings of these munitions have been corroded to the point where toxic substances such as TNT are continuously released into the seawater. The munition dumpsites are, therefore, hotspots of chemical pollution. However, predicting the distribution and spread of munition-related chemicals is challenging since (i) the associated dynamical processes are not well understood yet and (ii) some dumpsites are still unknown or poorly sampled. This study focuses on the Baltic Sea, which is estimated to contain more than 400,000 tons of conventional munitions, and particularly on the western Baltic Sea, a region with numerous documented or suspected dumpsites. We use high-resolution numerical simulations complemented by field measurements collected during several dedicated research campaigns to study the distribution and spread of munition-related contaminants. More than 45 virtual tracers have been released in the model to simulate the release of TNT from each contaminant source. Since the TNT release rates are unknown, we use inverse modeling and optimization techniques by combining the model results with the available observations. Thus, the simulated TNT is constrained, and we can obtain better estimates. Consistent with the observations, the simulated TNT distribution maps show elevated levels of TNT in the vicinity of the dumpsites. However, depending on the winds, the waves, and the ocean circulation, relatively high TNT levels are found throughout the western Baltic Sea. This indicates that this is not just a localized problem and that clearance operations are necessary to protect the marine environment. To further test the clearance strategies and prioritize the contaminant sources, we perform sensitivity experiments and construct risk maps.
The food-water-climate nexus of green infrastructure: Examining ecosystem services trade-offs of peri-urban agriculture
Authors: Segura-Barrero Ricard , Langemeyer Johannes , Badia Alba , Ventura Sergi , Vila-Traver Jaime , Villalba Gara
Published: March 2024

Emission reduction, heat mitigation, and improved access to water and food provision are increasingly critical challenges for urban areas in the context of global climate change adaptation and mitigation. The revival of local agricultural production is often lauded as a potential nature-based solution. However, an expansion of peri-urban agriculture (peri-UA) may entail significant trade-offs in the ecosystem services it provides.This study explores the impacts on the food-water-climate nexus of different scenarios of peri-urban agricultural expansion in a semi-arid, Mediterranean climate, addressing local food provision, freshwater use, local temperature regulation, global climate change mitigation, and the trade-offs thereof. Examining four theoretical land-use scenarios in the Metropolitan Area of Barcelona, the study integrates estimates of food provision and irrigation water requirements based on georeferenced urban metabolism approach with the local atmosphere and biogenic carbon balance estimates produced through the combination of an atmospheric model with a satellite and meteorological-driven biosphere model.Our study reveals that a 31.12 % (+17.27 km2) and 115.08 % (+64.25 km2) increase in the current peri-UA in the AMB, achieved by replacing natural non-forested and forest areas, results in an increase in local food production of 24.0 % (+16503 tons year-1) and 85.8 % (+58940 tons year-1), respectively. However, it would also increase the irrigation water requirements by 10.0 % (+3.2 hm3) and 43.5 % (+14.1 hm3), respectively. The analysis of the midday/midafternoon temperatures during a summer hot month reveals that peri-UA especially when it is irrigated can potentially reduce near-surface temperatures up to 0.7 °C with respect to a current scenario, however the air cooling affects principally located in rural regions with lower population density, while temperature reductions in the densest urban areas are minimal. If an expansion of Peri-UA goes at the expense of natural non-forested and forests areas, as in the scenarios we used, it has further the potential to disrupt the regional carbon balance, impacting the net ecosystem productivity of the AMB green infrastructure and overall carbon stocks with reductions in the net ecosystem productivity of up to 18.5 % and reduce total carbon stocks by 3.3 %.These findings, derived from an innovative and combined modelling approach, reveal significant trade-offs in ecosystem services associated with an expansion of peri-urban agriculture. It is likely that similar trade-offs would be observed with other nature-based solutions strategies. An integrated understanding of these trade-offs, facilitated by nexus approaches that combine different models, appears to be a promising direction for informing land-use decision-making in the context of urban climate adaptation and mitigation. 
Deep crustal deformation, anatexis and rheological significance of the Continental-Scale Chongshan Strike-Slip shear zone on the Southeastern Tibetan Plateau
Authors: Li Wenyuan , Cao Shuyun , Dong Yanlong , Zhan Lefan , Tao Lirong
Published: March 2024

Anatexis (i.e., partial melting) commonly occurs during crustal thickening, post-collisional collapse or exhumation and tectonic regime transition. It plays a crucial role in the evolution processes of tectono-thermal, rheological, and deformation behavior of the continental crust in orogenic belts. Continental-scale strike-slip shear zones often record significant tectono-magmatism and dynamic deformation processes of the crustal lithosphere. However, the genetic relationships and timing among the anatexis, deformation, and initial shearing along a strike-slip shear zone have not been well defined. The Chongshan shear zone (CS-SZ) is an important hundred-kilometer-long continental scale strike-slip shear zone on the Southeastern Tibetan Plateau. The CS-SZ involved contemporaneous activity with the adjacent sinistral Ailaoshan–Red River shear zone and dextral Gaoligong shear zone during the Cenozoic. In this study, we present a combined result of detailed field, microstructural, zircon U–Pb geochronology, geochemical and EBSD texture analyses of leucogranites and migmatites in the CS-SZ. The results indicate that most migmatites and leucogranites exhibit strong shear deformation and well-developed high-temperature mylonitic microstructures. The quartz aggregated from foliated leucogranites developed dominant high-temperature prism and prism
Sea ice strength in SI3
Authors: Fiedler Emma , Blockley Ed , Rousset Clement , Vancoppenolle Martin
Published: March 2024

The NEMO sea ice model, SI3, includes the simple formulation of Hibler (1979; H79) to parameterise the compressive strength of sea ice. This assumes that thick and compact sea ice has more strength than thin and low concentration sea ice. However, the H79 strength scheme does not consider physical assumptions around energy conservation. The strength scheme of Rothrock (1975; R75) is based on the amount of potential energy gained and frictional energy dissipated during ridging, and has been introduced to SI3. Additionally, the option for a negative exponential redistribution of ridged ice among thickness categories, to better approximate observations and improve stability compared to the existing uniform redistribution when using R75, has been included. The R75 strength formulation is stable and works well in SI3 at version 4.2 with an EVP rheology, under a Met Office forced NEMO/SI3 model configuration. Sea ice strength is generally reduced for the R75 scheme compared to H79. The most notable effect on the model output is a greater number of, and sharper, features in the resulting modelled ice field when using the R75 scheme compared to the H79 scheme, which are particularly apparent in the ice thickness field. An increase in the model effective resolution is therefore demonstrated.
Single vs. multi-objective optimization approaches to calibrate an event-based conceptual hydrological model using model output uncertainty framework.
Authors: Usman Muhammad Nabeel , Leandro Jorge , Broich Karl , Disse Markus
Published: March 2024

Flash floods have become one of the major natural hazards in central Europe, and climate change projections indicate that the frequency and severity of flash floods will increase in many areas across the world and in central Europe. The complexity involved in the flash flood generation makes it difficult to calibrate a hydrological model for the prediction of such peak hydrological events. This study investigates the best approach to calibrate an event-based conceptual HBV model, comparing different trials of single-objective, single-event multi-objective (SEMO), and multi-event-multi-objective (MEMO) model calibrations. Initially, three trials of single-objective calibration are performed w.r.t. RMSE, NSE, and BIAS separately, then three different trials of multi-objective optimization, i.e., SEMO-3D (single-event three objectives), MEMO-3D (mean of three objectives from two events), and MEMO-6D (two events six objectives) are formulated. Model performance was validated for several peak events via 90 % (confidence interval) CI-based output uncertainty quantification. The uncertainties associated with the model predictions are estimated stochastically using the ‘relative errors (REs)’ between the simulated (Qsim) and measured (Qobs) discharges as a likelihood measure. Single-objective model calibration demonstrated that significant trade-offs exist between different objective functions, and no unique parameter set can optimize all objectives simultaneously. Compared to the solutions of single-objective calibration, all the multi-objective calibration formulations produced relatively accurate and robust results during both model calibration and validation phases. The uncertainty intervals associated with all the trials of single-objective calibration and the SEMO-3D calibration failed to capture observed peaks of the validation events. The uncertainty bands associated with the ensembles of Pareto solutions from the MEMO-3D and MEMO-6D (six-dimensional) calibrations displayed better performance in reproducing and capturing more significant peak validation events. However, to bracket peaks of large flash flood events within the prediction uncertainty intervals, the MEMO-6D optimization outperformed all the single-objective, SEMO-3D, and MEMO-3D multi-objective calibration methods. This study suggests that the MEMO_6D is the best approach for predicting large flood events with lower model output uncertainties when the calibration is performed with a better combination of peak events.
Satellite observations reveal the activity cycle of a giant irrigation-triggered landslide in southern Peru
Authors: Song Chuang , Yu Chen , Li Zhenhong , Peng Jianbing
Published: March 2024

Irrigation-triggered landslides have received much attention in recent years as they directly threaten the agricultural production and the lives of local communities. Although the triggering of such landslides has been well documented, their long-term post-triggering dynamics and complete activity history (important for landslide risk assessment) remain poorly understood. In this study, we focus on one of the largest irrigation-triggered landslides in Peru, i.e., the Punillo Sur landslide. Previous studies failed to observe and characterize the full cycle of landslide activity due to their inadequate monitoring capabilities, prompting us to combine satellite interferometric synthetic aperture radar (InSAR) and optical offset measurements to track its full 8.5-year kinematics from 2014 to 2023.Our key findings include: (1) The landslide experienced three times of very large accelerations (i.e., three activity cycles) respectively in 2016, 2019 and 2022, with accumulated displacements of over 150 m; (2) These large accelerations, accompanied by headscarp retrogression, were all found to initiate from precursory/sudden movements of > 10 cm/yr (observed by InSAR) and were driven by long-term infiltration of irrigation water; (3) The southern portion of the landslide exhibited a greater magnitude of acceleration due to its thinner sliding layer that favors seepage-driven motion; (4) After the three large accelerations, the landslide invariably shifted to deceleration without catastrophic failures, which was found to be controlled by water evacuation and rate-strengthening friction.These findings will serve as import materials for understanding the cycle of landslide activity and highlighting the prolonged effect of irrigation water on landslide dynamics. This will greatly increase our understanding of the long-term risk of irrigation-triggered landslides. Based on our findings, we also proposed critical disaster prevention/mitigation measures to support local communities in their disaster management efforts.
Role of temperature and nutrients as drivers of resource allocation, elemental stoichiometry, metabolism and growth in marine phytoplankton
Authors: Marañón Emilio , Fernández-González Cristina , Duhamel Solange , Segura Mariona
Published: March 2024

We have conducted experiments with both laboratory cultures and natural plankton assemblages, together with basin-scale observations across the Atlantic Ocean, to investigate the interactive effects of temperature and nutrient supply on phytoplankton across multiple levels of biological organization, including molecules, cells, populations and communities. Laboratory data indicate that nutrient supply has a stronger effect than temperature on photosynthetic protein abundance, C:N stoichiometry, photosynthesis and growth. Due to changing resource allocation into photosynthetic machinery, the chlorophyll a (chl a) content of cells is strongly dependent on both temperature and nutrient availability, which has implications for the use of chl a concentration as a proxy for phytoplankton biomass in the ocean. Across the tropical and subtropical Atlantic, experimental nutrient enrichment consistently causes an increase in chl a concentration, picoeukaryote abundance and the contribution of small nanophytoplankton to total biomass, all of which take place irrespective of temperature. Light-harvesting capacity is synergistically stimulated by warming and nutrient addition in both picocyanobacteria and picoeukaryotes. The latitudinal variability in elemental composition of different phytoplankton groups, determined on single cells with X-ray microanalysis across the temperate, subtropical and tropical Atlantic, reveals the effect of changing temperature and nutrient supply on C:N:P stoichiometry. Our experimental and observational results suggest that while changes in nutrient supply have a stronger effect than temperature on growth, metabolic rates, community structure and elemental stoichiometry, the warming of the surface ocean may increase the ability of tropical phytoplankton assemblages to exploit events of enhanced nutrient availability. Across multiple levels of biological organization, nutrient limitation tends to reduce the effects of temperature on phytoplankton ecophysiology.
A change in solar radio spectrum during the decay of the Modern Maximum
Authors: Mursula Kalevi , Pevtsov Alexei , Asikainen Timo , Tähtinen Ismo , Yeates Anthony
Published: March 2024

The Sun experienced a period of unprecedented activity during solar cycle 19 in 1950s and 1960s, now called the Modern Maximum (MM). The decay of the MM has changed the Sun, the heliosphere and the planetary environments in many ways. However, this decay may not have proceeded synchronously in all solar parameters. One of the related key issues is if the relation between the two long parameters of solar activity, sunspot number and the solar 10.7cm radio flux, has remained the same during this decay. While a number of studies agree that this relation has indeed changed, no consensus on its validity exists. A recent study argues that there is an inhomogeneity in the 10.7cm radio flux in 1980, which led to a step-like jump ("1980 jump") in this relation. If true, this would imply that the 10.7cm radio flux is ineligible for long-term studies, which would seriously impede versatile studies of the Sun during the MM.Here we use the 10.7cm radio flux and four other, independent radio flux measurements, the sunspot number, the MgII index and the number of solar active regions in order to study their mutual relations during the decay of MM. We find that all the five radio fluxes depict an increasing trend with respect to the sunspot number from 1970s to 2010s. This excludes the interpretation of the "1980 jump" as an inhomogeneity in the 10.7cm flux, and re-establishes the 10.7cm flux as a reliable and homogeneous long-term measure of solar activity.We find that the fluxes of longer radio waves increased with respect to the shorter waves, which implies a long-term change in the solar spectrum at radio frequencies. We also find that both the MgII index and the number of active regions increased with respect to the sunspot number, indicating a difference in the long-term evolution in chromospheric and photospheric parameters.Our results give evidence for important structural changes in solar magnetic fields and solar atmosphere during the decay of the MM when solar activity weakened considerably. These changes have not been reliably documented so far. We also emphasise that the changing relation between the different (e.g. photospheric and chromospheric) parameters should be taken into account when using sunspot number or any single parameter in long-term studies of solar activity.
Towards assessing the impacts of large ground-mounted solar parks on the hydrological cycle: an analysis of runoff changes with EPA-SWMM software 
Authors: Gullotta Aurora , Aschale Tagele Mossie , Peres David J. , Sciuto Guido , Cancelliere Antonino
Published: March 2024

Among all the renewable energy sources, solar photovoltaic (PV) is one of the most widespread in the word. Although solar energy is universally recognised as environmentally friendly energy source, impacts on surface hydrology of large parks have not been comprehensively addressed in literature. With growing concern over the impact of land use changes on stormwater runoff, the construction of large-scale solar power plants may face obstacles in the future unless appropriate quantification of this impact is addressed, and proper measures are taken to mitigate potential increment of flow peak and volume discharge. Assessment of runoff generation in PV solar parks can be carried out by modelling-based approaches, that have the advantage, with respect to purely experimental studies, to allow the investigation of the influence of different hydrological conditions. Moreover, the modelling-based approach enables the possibility to assess the park behavior in the short and in the long-term conditions. Analysis of the literature on the topic highlights a research gap consisting in the lack of a comprehensive tool for the assessment of the impacts of real-scale solar parks on stormwater runoff, by considering the hydrological processes occurring within the park and all the variables affecting the park response to precipitation events. In this work, we propose a novel conceptualization of PV solar parks response to precipitation events capitalizing on the use of the free and open-source Storm Water Management Model (SWMM). The conceptualization allows to take into account the complex hydrological process occurring in the solar parks during precipitation events and to assess how the process of runoff in the park is affected by the extension of the PV installation, soil properties and the characteristics of the rainfall events. Moreover, effects of long-term changes in roughness surface induced by the presence of the panels are taken into account in the analysis. We demonstrate the potentialities of the proposed approach considering a layout of the PV installation (panels size and inclination) as well as characteristics of the precipitation events that are encountered in Sicily (south Italy). In all the simulations, outflow discharge from the park is compared to that from a reference catchment to evaluate variations of peak flow and runoff volume. Results highlight no practical changes in runoff in the short term after installation. However, in the long term, modifications in soil cover may lead to some potential increase of runoff. For instance, increments of the peak flow from the solar park up to 21% and 35% are obtained for roughness coefficient reductions of 10% and 20%, respectively. The proposed modelling approach can be beneficial for studying hydrological impacts of solar parks and thus for planning measures for their mitigation.
Developing Energy Communities with Intelligent and Sustainable Technologies – First Results
Authors: Los Alexander , Moody Rebecca , Andriotis Charalampos , Khademi Seyran , Morato Pablo G.
Published: March 2024

In a recently started scientific project aiming at “Developing Energy Communities with Intelligent and Sustainable Technologies” (DE-CIST), we combine physical data on buildings in Rotterdam (The Netherlands) with socio-economic data from neighbourhoods and input from citizens and communities. Individual building data, together with meteorological, air quality, and GHG emission data, are processed by a novel AI solution classifying neighbourhoods and buildings based on their current status of energy sustainability, and their energy saving and emission reduction potential. This, in turn, informs measures that fit best per building and per neighborhood. Yet, to reveal which buildings or neighbourhoods are the worst off, we approach the problem using a socio-technological transitions perspective, which takes into account the needs and concerns of all citizens, notably the ones of the most vulnerable populations to reveal energy poverty and injustice. Using this approach, we will show which neighbourhoods can benefit the most, technically as well as socially.Our presentation will start with an overview of the DE-CIST project and demonstrate how the combination of environmental and social information can make the energy transition process more efficient, economically viable, equitable, and more human. From recent analysis we conclude that energy communities have a strong effect on trust and engagement, fostering environmental awareness and motivation to save energy. In our presentation we will provide further insights into energy efficiency and renovations of buildings, and into how we can realize a fair, coherent energy transition process using a combination of results from AI-based methods, environmental modelling (of air pollution), and our analysis of the interviews with stakeholders and survey data. 
How can we quantify, explain, and apply the uncertainty of complex soil maps predicted with neural networks?
Authors: Rau Kerstin , Eggensperger Katharina , Schneider Frank , Hennig Philipp , Scholten Thomas
Published: March 2024

Artificial neural networks (ANNs) have proven to be a useful tool for complex questions that involve large amounts of data, for example, predicting soil classes on various scales. Our use case of predicting soil maps with ANNs is in high demand by government agencies, construction companies, or farmers, given cost and time intensive field work.However, there are two main challenges when applying ANNs. In their most common form, deep learning algorithms do not provide interpretable predictive uncertainty. This means that properties of an ANN such as the certainty and plausibility of the predicted variables, rely on the interpretation by experts rather than being quantified by evaluation metrics validating the ANNs. This leads to the second challenge: these algorithms have shown a high confidence in their predictions in areas geographically distant from the training area or areas only sparsely covered by training data.To tackle these challenges, we use the Bayesian deep learning approach “last-layer Laplace approximation”, which is specifically designed to quantify uncertainty into deep networks, in our explorative study on soil classification. It corrects the overconfident areas without reducing the accuracy of the predictions, giving us a more realistic uncertainty expression of the model's prediction.  In our study area in southern Germany we divide the soils into typical soils of valleys, the Swabian Jura and the Black Forest. As a test case, we then explicitly exclude the soil types of Swabian Jura and Black Forest in the training area but include these regions in the prediction. These two regions are characterized by very different soil types compared to the rest of the study area due to their considerably different geology, climate, and terrain.Our findings emphasize the need to address the issue of overconfidence in ANNs, particularly for distant regions from the training area. Moreover, the insights gained from this research are not only limited to addressing overconfidence in ANNs, but also offer valuable information on the predictability of soil types and identifying knowledge gaps. By analysing regions where the model has limited data support and, consequently, high uncertainty, stakeholders can recognize the areas that require more data collection efforts.
Multivariate statistical analysis of mafic- and ultramafic-hosted seafloor massive sulfides
Authors: Nimis Paolo , Aminizadkovij Nasser , Meyzen Christine , Toffolo Luca , Melekestseva Irina , Paccagnella Omar , Patten Clifford
Published: March 2024

Seafloor massive sulfide (MS) deposits on oceanic spreading centers have variable concentrations of base metals (mostly Cu, Zn), precious metals (Au, Ag), critical metals (Co, Ni), and other trace elements. The geological factors that control this geochemical variability are still a matter of debate. In particular, the role of the composition of substrate rocks (specifically mafic vs. ultramafic) has been variably considered to be decisive or subordinate. In a previous study (Toffolo et al., 2020, Earth Sci. Rev.), we have investigated these factors by means of robust principal component and factor analysis of chemical data for MS samples from mid-ocean ridges worldwide. We found that a large part of the observed variability is produced by a combination of three independent factors, interpreted to reflect (in order of importance): (1) the temperature of deposition, which controls the relative enrichments in (Cu, Se, Co) vs. (Pb, Sb, Zn, Ag), (2) the ridge spreading rate, which influences the oceanic basement structure and the rock-to-water ratios, leading to opposite behaviors of (Au, Ag) vs. Ni, and (3) zone refining. Unexpectedly, the composition of the substrate did not emerge as a statistically significant independent factor. An important limit of our previous investigation was that literature data were often incomplete, thus limiting the number of samples and of chemical elements for the multivariate statistical analysis. We have now addressed this problem by using statistical imputation techniques and by integrating the database with additional literature and in-house data for present-day deposits on mid-ocean ridges and ancient deposits in ophiolites from different settings (supra-subduction-zone, mid-ocean ridge, ocean-continent transition). As a result, undersampling of ultramafic-hosted deposits was significantly reduced and the number of elements was raised to 11, including Cu, Zn, Pb, Au, Ag, Co, Ni, Se, Sb, Mo and the previously excluded As. The integrated database essentially confirms our previous findings. In addition, deposits in supra-subduction-zone ophiolites show factor scores typical of high deposition temperatures and high rock-to-water ratios, consistent with their formation on infant-arc, slow-spreading centers. The potential influence of other local geological factors will be discussed.
Geospatial suitability mapping for targeted vegetable production in fragile African regions
Authors: Dembélé Moctar , Leh Mansoor , Wickramasinghe Darshana , Velpuri Naga , Sanogo Karamoko , Tegegne Desalegne , Andarcia Mariangel Garcia , Schmitter Petra
Published: March 2024

Enabling the resilience of local food systems is crucial to ensure a steady supply of nutritious food to people living in fragile and conflict-affected locations. While the majority of interventions often focus on staple crops, there is an increasing tendency by humanitarian organizations to include vegetable production solutions in their programs. However, information on land suitability for vegetable production is usually lacking or available at a coarse spatial resolution, thereby limiting targeted interventions for smallholder farmers.This study proposes a comprehensive geospatial data-driven framework for mapping suitable areas for vegetable production in Africa using a machine learning algorithm (ML) implemented in Google Earth Engine (GEE) and a Multi-Criteria Decision Analysis (MCA) approach. Mali (West Africa) and Ethiopia (East Africa) are selected as case studies given the current fragility of both countries, and support provided by the USAID's Bureau for Humanitarian Assistance (BHA). Field data of vegetable production locations was collected to train and validate the ML and MCA models. Several publicly available geospatial datasets, including FAO’s WaPOR database, were reviewed to select the predictor variables, which include information on climate, soil, topography, surface water, groundwater, socioeconomics and disaster risks. A suitability map was produced for all vegetables, and separate suitability maps were generated for the top five most cultivated vegetables in Mali and Ethiopia.Comparison of the ML approach to the MCA approach revealed a lower performance of the former due to the limited availability of field data, thereby highlighting the benefit of expert knowledge in addition to the data-driven approach. The results show that the most suitable areas are found in the region of Segou in Mali (up to 88%), while the region of Oromia has the most suitable areas in Ethiopia (up to 85%). The resulting maps of land suitability for vegetable production serve to develop an irrigation investment targeting tool, which can be used to assist humanitarian organizations in implementing suitable irrigation solutions for vegetables.
Spatiotemporal variations of manganese-mediated litter decompositions across oxic-anoxic transitions in deciduous forest soils
Authors: Chin Nathan , Van Der Loo Egon , DeAngelis Kristen , Keiluweit Marco
Published: March 2024

Manganese (Mn) has been demonstrated to be a significant driver of litter decomposition in forest soils, regulating nutrient cycling, CO2 production, and ultimately soil carbon storage across forest systems globally. Recent evidence suggests that Mn-driven litter decomposition is dependent on ubiquitous oxic-anoxic interfaces in soils, which act as potential hotspots for the formation of reactive Mn(III) oxidants. Here we will show how oxic-anoxic interfaces in forest soils, arising from spatiotemporal variations in moisture, affect Mn(III)-driven litter decomposition. To do this, we tested the effect of in-field Mn additions on litter decomposition along a deciduous forest upland-to-wetland transect exhibiting dynamics in oxic-anoxic transitions. Within Mn-amended litterbags incubated across the transect, we monitored spatiotemporal variations in Mn(III) formation and litter decomposition. Over the course of the experiment, increased Mn amendments in litter correlated with both enhanced CO2 production as greater mass loss compared to untreated litter, particularly during periods of greater Mn(II) oxidation. Wet-chemical extractions revealed increasing Mn(II) oxidation over the growing season in elevated Mn treatments, resulting in enhanced Mn(III) formation. Additionally, the greater abundance of Mn(III) phases in Mn treated litter compared to untreated litter was significantly correlated to a greater degree of oxidation in the litter and greater water extractability of litter carbon, demonstrating enhanced litter decomposition in Mn amended litter. Across the forest transect, Mn oxidation and Mn(III) formation were greatest at sites with greater presence of oxic-anoxic transitions, which coincided with the sites exhibiting higher litter decomposition. Therefore, our results show that Mn(III)-mediated litter decomposition occur in hotspots present at oxic-anoxic interfaces across spatiotemporal gradients in forest soils. These findings provide first insights into the spatiotemporal links between Mn and carbon coupled redox cycling in forest ecosystems.
Summer drought predictability in the Mediterranean region in seasonal forecasts
Authors: Cerato Giada , Bellomo Katinka , von Hardenberg Jost
Published: March 2024

The Mediterranean region has been identified as an important climate change hotspot, over the 21st century both air temperature and its extremes are projected to rise at a rate surpassing that of the global average and a significant decrease of average summer precipitation is projected, particularly for the western Mediterranean. On average, Mediterranean droughts have become more frequent and intense in recent years and are expected to become more widespread in many regions. These prolonged dry spells pose a substantial threat to agriculture and impact several socio-economic sectors. In this context, long-range weather forecasting has emerged as a promising tool for seasonal drought risk assessment. However, the interpretation of the forecasting products is not always straightforward due to their inherent probabilistic nature. Therefore, a rigorous evaluation process is needed to determine the extent to which these forecasts provide a fruitful advantage over much simpler forecasting systems, such as those based on climatology. In this study, we use the latest version of ECMWF’s seasonal prediction system (SEAS5) to understand its skill in predicting summer droughts. The Standardized Precipitation Evapotranspiration Index (SPEI) aggregated over different lead times is employed to mark below-normal dryness conditions in August. We use a comprehensive set of evaluation metrics to gain insight into the accuracy, systematic biases, association, discrimination and sharpness of the forecast system. Our findings reveal that up to 3 months lead time, seasonal forecasts show stronger association and discrimination skills than the climatological forecast, especially in the Southern Mediterranean, although the prediction quality in terms of accuracy and sharpness is limited. On the other hand, extending the forecast range up to 6 months lead time dramatically reduces its predictability skill, with the system mostly underperforming elementary climatological predictions. This approach is then extended to examine the full ensemble of seasonal forecasting systems provided by the Copernicus Climate Change Service (C3S) to test their skill in predicting droughts. Our findings can help an informed use of seasonal forecasts of droughts and the development of related climate services.
Mass transport induced by 5-th order nonlinear water waves
Authors: Grzonka Laura , Cieślikiewicz Witold
Published: March 2024

Linear theory of water waves is reasonable to use only in the case of small waves. As the waves’ steepness increases, nonlinear effects start to play a role too significant to be neglected. One of the widely used and commonly accepted methods of calculating water wave kinematics is Fenton’s method (Fenton 1985). It allows one to find free surface elevation and velocity potential up to 5th order in wave steepness.In case of wave-related phenomena, among quantities of interest is wave-induced mass transport as its knowledge is necessary to find tracer transport, like oil pollution, algae bloom, or plastic. Cieślikiewicz & Gudmestad (1994) introduced a method of calculating mass transport induced by harmonic and random water waves. A key contribution in this study was taking into account the emergence effect: in the Eulerian frame of reference, a fixed point in space in the vicinity of the free surface emerges and submerges under the water. The primary objective of the present study was to integrate Fenton’s kinematics into the Cieślikiewicz & Gudmestad methodology for more accurately calculating the wave-induced mass transport. I used the perturbation scheme and the technique of transformation of random variables (Huang et al. 1983). The results demonstrate strong agreement with previous approaches. Cieślikiewicz, W. & Gudmestad, O. T. (1994). Mass transport within the free surface zone of water waves. Wave Motion, 19(2), 145–158. https://doi.org/10.1016/0165-2125(94)90063-9Fenton, J. D. (1985). A Fifth-Order Stokes Theory for Steady Waves. Journal of Waterway, Port, Coastal, and Ocean Engineering, 2(111), 216–234Huang, N. E., Long, S. R., Tung, C.-C., Yuan, Y., & Bliven, L. F. (1983). A Non-Gaussian Statistical Model for Surface Elevation of Nonlinear Random Wave Fields. Journal of Geophysical Research, 88(C12), 7597–7606; Papoulis, A., & Pillai, S. U. (2002). Probability, Random Variables and Stochastic Processes. McGraw-Hill
Late-Neogene to Quaternary uplift, relief and drainage evolution in the western French Alps: new insights from surface and underground karst archives in the subalpine massifs
Authors: Valla Pierre , Mai Yung Sen Vivien , Rolland Yann , Jaillet Stéphane , Robert Xavier , Carcaillet Julien , Crouzet Christian , Bruguier Olivier , Pons-Branchu Edwige , Malet Emmanuel , Boutin Paradis Nouméa , Moiret Léo
Published: March 2024

The late-Neogene to Quaternary evolution of the western European Alps has been marked by major changes in geodynamic, tectonic and climatic forcing. The complex interplay between endogenic and exogenic processes has resulted in rock-uplift changes, topographic relief development and major drainage pattern reorganizations. However, quantitative estimates on these interrelated mechanisms have remained scarce due to the poor preservation on surface geological archives in the alpine massifs. This is the case for the frontal part of western Alps, i.e. the subalpine massifs, for which the overall tectonic architecture and total deformation/uplift are well constrained but the timing and rates remained poorly known.Here, we focus on the Vercors subalpine massif and specifically target karstic systems in the upper Bourne catchment that have been developed and potentially preserved over million-year timescales. Our study combines karst network analysis with the investigation of surface geomorphological markers (abandoned canyons) to provide an incision history and integrated geomorphic evolution of the Bourne catchment from the late Neogene to Quaternary. We develop an innovative multi-method approach with 3D mapping of both surface and underground markers associated to geochronological investigation of preserved detrital sediments (26Al/10Be burial dating, U/Pb dating, paleomagnetism) and speleothems (U-Th dating). Our results show first changes in the surface drainage pattern at ~10 Ma for the Bourne catchment, in agreement with tectonic deformation and topographic uplift at that time. The Bourne incision history reveals a multi-stage complex evolution, with a late Neogene incision phase followed by relative quiescence during the Pliocene. The late-stage history of the Bourne is marked by a second incision phase since ca. 2 Ma that could be linked to isostatic response to relief development during major Alpine glaciations. Our new results nicely complement recent data from the nearby Devoluy massif, and indicate a late-Neogene structuration and uplift of the subalpine massifs which has been relatively contemporaneous with the exhumation of the external crystalline massifs (Belledonne, Ecrins-Pelvoux). This tectonic structuring resulted in the present-day “plateau” configuration of the subalpine massifs, and their uplift led to a major change from an earlier radial into the modern “orogen-parallel” drainage system, which was then marked by the Quaternary alpine glaciations.
Sub-seasonal prediction of heat-related mortality in Switzerland
Authors: Domeisen Daniela I.V. , Pyrina Maria , Büeler Dominik , Vicedo-Cabrera Ana M. , Sivaraj Sidharth , Imamovic Adel , Spirig Christoph , Moret Lionel
Published: March 2024

Heatwaves have various impacts on human health, including an increase in premature mortality. The summers of 2018 and 2022 are two prominent examples with record-breaking temperatures leading to thousands of excess deaths in Europe. Nevertheless, there is a limited assessment of the potential for heat-health warning systems on timescales up to several weeks ahead at a regional level. This study combines methods of climate epidemiology and sub-seasonal forecasting to predict the expected heat-related mortality for two regions in Switzerland during the summers of 2018 and 2022. The sub-seasonal forecasts were first downscaled to a 2km-by-2km grid using a quantile mapping approach. The statistical heat-mortality relationship for the Swiss cantons of Zurich and Geneva between 1990 and 2017 was estimated in a two-stage time-series analysis using observed daily temperature and mortality. Then, heat-related mortality in the summers of 2018 and 2022 was calculated using the estimated heat-mortality relationship and the observed total mortality and temperature. The resulting estimated heat-related mortality was subsequently compared with the predicted heat-related mortality based on sub-seasonal temperature forecasts. Preliminary results show that we can successfully predict short-term heat-related mortality peaks for lead times up to 2 weeks, while longer periods of heat-related mortality can be anticipated by lead week 3 and even lead week 4 forecasts. Our findings demonstrate that sub-seasonal forecasts can be a valuable tool for estimating and potentially issuing warnings for the excess health burden observed during central European summers.