bluuebunny/crossref_metadata_2025 huggingface dataset:
Changing spatio-temporal characteristics of extreme rainfall events under climate change using high resolution climate projections 
Authors: Devitt Laura , Coxon Gemma , Neal Jeffrey , Archer Leanne , Bates Paul , Kendon Elizabeth
Published: March 2024

Extreme precipitation is projected to intensify and occur more frequently under climate change. However, the effect of global warming on the spatial and temporal structure of extreme rainfall events at the local scale is uncertain. In the UK, the current method for estimating changes in flood hazard under climate change involves applying a simple multiplicative uplift to spatially uniform catchment rainfall. This approach neglects spatio-temporal characteristics of rainfall, which are known to be important for flood hazards. The UCKP Local Convection Permitting Model (CPM) has for the first time provided the capacity to assess these characteristics of rainfall at the local scale. Here, we use an ensemble of 2.2km hourly convection-permitting transient projections from UKCP Local to identify changes in the spatial and temporal characteristics of precipitation extremes over 100-years (1981-2080) across the UK. The analysis uses an ‘event-based’ approach, exploring seasonal changes in the peak intensity, total rainfall, and duration of events, but also changes in the spatial extent and temporal clustering of events through time. We identify ~13000 extreme rainfall events across the UK over the 100-year period. Event peaks are identified using a seasonal and time-varying threshold (99th percentile) on hourly rainfall rates, and event start and stop times are extracted using a lower threshold (20th percentile). We identify seasonal differences in how spatial extents of rainfall extremes will change, with winter and spring events growing, but summer and autumn events reducing in areal coverage. We also identify changes in the sub-seasonal timing of rainfall extremes, with events becoming more clustered, particularly during the winter months. Understanding changes in the spatial and temporal characteristics of rainfall events is critical as they may compound with increases in rainfall intensity, exacerbating the impacts of flooding.
Heterogeneous mantle source of Mauna Loa volcano (Hawai’ian plume) revealed by Sr-isotope and trace elements signatures of olivine-hosted melt inclusions
Authors: Vezinet Adrien , Barbera Blas , Sobolev Alexander V. , Batanova Valentina G. , Kazzy Charbel , Chugunov Aleksandr V.
Published: March 2024

Melt inclusions hosted in highly magnesian olivine crystals have proven invaluable for probing the composition of the mantle through time since their geochemical signature is reflecting that of parental melt. Additionally, the geochemical study of melt inclusions has shown to be more suited to identify the heterogeneity in the magma from which they crystallized, particularly the chemically depleted domains [1, 2]. Here, we will present new major, minor & trace elements, H2O contents and Sr-isotope signature of more than 300 olivine-hosted naturally quenched melt inclusions from Pu’u Wahi (910 yr-old) and Puʻu Mahana (ca. 50 kyr-old), two ash cones associated with Mauna Loa, the largest shield volcano of the Hawai’ian seamount chain. In order to have a high degree of confidence in the geochemical proxies, Sr-isotope and trace elements analyses were conducted through laser ablation split stream (LASS) protocol on top of EPMA and Raman (for H2O contents) analytical spots. Preliminary results in our new set of inclusions show the presence of high (Sr/Ce)N inclusions, previously interpreted as indicating either gabbro influence in the source of the plume [3] or interactions between plagioclase-rich cumulates and percolating mantle-derived melts [4]. Further, “ultra-depleted melts”, UDM, indicated by K2O contents < 0.1 wt.% identified in [1], have also been re-identified in this new set of inclusions (not analyzed for Sr-isotope yet). 87Sr/86Sr of non-UDM inclusions ranges from 0.70361±0.00025 to 0.70427±0.00025, i.e. analogous to the most recent TIMS values [4, 5]. Additional LASS analyses will be conducted before the meeting. The full set of analyses will be confronted to published results on the same volcano [1, 3-6] and integrated in a larger framework of interactions between mantle plume and consequences for plate tectonic.References:Sobolev, A.V., et al., Nature, 2011. 476(7361).
Stracke, A., et al., Nature Geoscience, 2019. 12(10).
Sobolev, A.V., et al., Nature, 2000. 404(6781).
Anderson, O.E., et al., Geochemistry, Geophysics, Geosystems, 2021. 22(4).
Reinhard, A., et al., Chemical Geology, 2018. 495.
Sobolev, A.V., et al., Nature, 2005. 434(7033).
Analyzing the Efficacy of Precipitation in Aerosol Clearance Using Lidar, Micro Rain Radar, and Disdrometer Observations.
Authors: Lolli Simone , Lewis Jasper R. , Dolinar Erica K. , Campbell James R. , Welton Ellsworth J.
Published: March 2024

We quantitatively assess the aerosol removal of aerosols by precipitation, using lidar, micro rain radar, and disdrometer observations. Precipitation acts as an effective means of cleansing the atmosphere of aerosols through several processes. Fine and coarse aerosol particles are each subject to below-cloud scavenging, characterized by distinct coefficients for each particle category. Data from lidar, micro rain radar, and disdrometers have revealed aerosol depletion at the melting layer, where the wet scavenging coefficient (WSC) is influenced by the rainfall intensity and the interaction efficacy between raindrops and aerosol particles. The synergy of cloud dynamics and precipitation is pivotal in aerosol removal, with lidar data indicating the influence of evaporation and the modulation of latent heat in the process. Precipitation is found to markedly expedite the clearance of aerosols from the air, accounting for up to 80% of the total removal under specific scenarios. This investigation underscores the vital function of precipitation in the dynamics of atmospheric aerosols and sheds light on the consequential environmental and climate-related impacts.
Validation of Model Results in Response to the COSPAR ISWAT Challenge
Authors: Wang Dedong , Shprits Yuri , Castillo Tibocha Angelica Maria , Drozdov Alexander
Published: March 2024

The COSPAR International Space Weather Action Team (ISWAT) is a global hub for collaborations addressing challenges across the field of space weather. One of the objectives of the G3-04 team “Internal Charging Effects and the Relevant Space Environment” is model performance assessment and improvement. One of the expected outputs is a more systematic assessment of model performance under different conditions. The G3-04 team proposed performing benchmarking challenge runs. In this study, in response to the first benchmarking challenge (long-term simulation), we perform simulations for the year 2017 to validate the Versatile Electron Radiation Belt (VERB) code. The challenge requires not using any of the measurements from the NASA' s Van Allen Probes for setting up parameters of the code, such as boundary and initial conditions. In our simulations, we use data from the Geostationary Operational Environmental Satellites (GOES) to set up the outer boundary condition, which is the only data input for simulations. We validate our simulation results against measurements from Van Allen Probes. In particular, we ‘fly’ a virtual satellite through our simulation results and compare the simulated differential electron fluxes at 0.9 MeV and 57.27 degrees local pitch-angle with the fluxes measured by the Van Allen Probes. In general, our simulation results show good agreement with observations. We calculated several different matrices to validate our simulation results against satellite observations. Using the similar approach, we extend our simulations to several years long period and validate our simulation results against satellite observations in both long-term and specific geomagnetic storms. Several different validation matrices are calculated for both long-term and specific events.
 Oxygen-fugacity evolution of magmatic Ni-Cu sulfide deposits in East Kunlun: Insights from Cr-spinel composition 
Authors: Jia Lihui , Chen Yi , Su Bin , Mao Qian , Zhang Di
Published: March 2024

Redox state of parental magma would have undergone significant changes from partial melting in the mantle to emplacement in the shallow crust, which might play a critical role in the genesis of magmatic Ni-Cu sulfide deposits in convergent tectonic settings. In this study, we present mineralogy, petrology, and fO2 calculations of the Xiarihamu Ni-Cu deposit and the Shitoukengde non-mineralized intrusion in the East Kunlun orogenic belt. Olivine-spinel pairs in different magmatic stages were chosen to estimate the magma fO2 (olivine-spinel oxybarometer), track the changes in oxygen fugacity during magmatic evolution, and reveal its influence on the metallogenic mechanism of the Ni-Cu sulfide deposit. Spinel Fe3+/ΣFe ratios determined by a secondary standard calibration method using electron microprobe. Those ratios of the Xiarihamu Ni-Cu deposit vary from 0.32±0.09 to 0.12±0.01, corresponding to magma fO2 values ranging from ΔQFM+2.2±1.0 to ΔQFM-0.6±0.2. By contrast, those of the Shitoukengde mafic-ultramafic intrusion increase from 0.07±0.02 to 0.23±0.04, corresponding to magma fO2 varying from ΔQFM-1.3±0.3 to ΔQFM+1.0±0.5. A positive correlation between fO2 and Cr-spinel Fe3+/ΣFe ratios suggests that the Cr-spinel Fe3+/ΣFe ratios can be used as an indicator for magma fO2. The high fO2 (QFM+2.2) of the harzburgite in the Xiarihamu Ni-Cu deposit suggests that the most primitive magma was characterized by relatively oxidized conditions, and then became reduced during magmatic evolution, causing S saturation and sulfide segregation to form the Xiarihamu Ni-Cu deposit. The evolution trend of the magma fO2 can be reasonably explained by metasomatism in mantle source by subduction-related fluid and addition of external reduced sulfur from country gneisses (1.08–1.14 wt.% S) during crustal processes. Conversely, the primitive magma of the Shitoukengde intrusion was reduced and gradually became oxidized (from QFM-1.3 to QFM+1.0) during crystallization. Fractional crystallization of large amounts of Cr-spinel can reasonably explain the increasing magma fO2 during magmatic evolution, which would hamper sulfide precipitation in the Shitoukengde intrusion. We propose that the temporal evolution of oxygen fugacity of the mantle-derived magma can be used as one of the indicators for evaluating metallogenic potential of Ni-Cu sulfide deposits, and reduction processes from mantle source to shallow crust play an important role in the genesis of magmatic Ni-Cu sulfide deposits.
A Remote Sensing Data Fusion algorithm for Near Real time monitoring of Volcanic Radiative Power
Authors: Di Bella Giovanni Salvatore , Corradino Claudia , Cariello Simona , Torrisi Federica , Del Negro Ciro
Published: March 2024

Nowadays, near-real time volcano monitoring at global scale is made possible thanks to the thermal infrared sensors on board of several satellite platforms providing accurate estimates of the volcanic thermal emissions. In particular, they are able to provide reliable estimates of the Volcanic Radiative Power (VRP), i.e. the heat radiated during the volcanic activity. In addition, Remote Sensing Data Fusion (RSDF) techniques allow to combine data from multiple satellite sensors to improve the potential values of the single source and to produce a high-quality data representation. Fusion techniques are useful for a variety of applications, ranging from object detection, to object tracking, change detection. In particular, we aim to use them to integrate the different satellite data acquired with different spatial and spectral resolutions to produce fused data that contains more detailed information than each of the data sources. We introduce a novel RSDF algorithm deployed in a Cloud Computing environment to monitor VRP worldwide from multiple multispectral satellite sensors, namely the polar MODIS, SLSTR and VIIRS and the geostationary SEVIRI. The RSDF algorithm demonstrates heightened sensitivity in detecting high-temperature volcanic features and thus VRP monitoring compared to conventional already processed Level 2 products available online. Specifically, the overall accuracy has improved in terms of omitted rate and false detections, reducing from 78% to 5.3% and from 6.5% to 4.7%, respectively. The decision to combine the use of different satellite sensors stems from the need to offer complete continuous monitoring of each volcanological phenomenon, taking advantage of each sensor's own characteristics.
Time-lapse GPR Measurements for Observing Shallow Cryo-Hydrogeological Borders in Spitsbergen's Fuglebekken Catchment
Authors: Izadi Yazdanabadi Marjan , Marciniak Artur , Oryński Szymon , Wawrzyniak Tomasz , Osuch Marzena
Published: March 2024

This study investigates the changes in shallow cryo-hydrogeological layers over time using Ground Penetrating Radar (GPR) in the unique Arctic environment of the Fuglebekken catchment on Spitsbergen Island. Accurate identification of permafrost changes is essential for understanding geotechnical and environmental processes, making precise monitoring imperative. GPR has proven to be a valuable non-destructive method, providing high-resolution spatially distributed data in permafrost regions and overcoming environmental limitations inherent in Arctic areas.Utilizing a 250 MHz shielded antenna, GPR measurements facilitated the identification of the groundwater layer and changes in the top border of permafrost at different seasons in the Fuglebekken catchment. A distinctive aspect of this research involved the repetition of GPR profiles at the same location during three different seasons, enabling the observation of temporal variations in subsurface conditions across different seasons. These profiles were complemented by strategically placed boreholes and piezometers recording ground temperature at various depths and groundwater levels, providing key data for the validation and correlation of GPR results. Additionally, drone-based digital elevation models (DEM) were employed during GPR data processing to enhance the accuracy of results.In the majority of recorded profiles, GPR measurements captured well-defined reflections of subsurface features. The emphasis is on revealing changes over time in the study area by distinguishing geological structures from the groundwater and upper permafrost boundaries. The study convincingly demonstrated the efficacy of GPR in capturing underground time-lapse changes throughout the studied area. The comprehensive insights gained through GPR offered distinct advantages over traditional methods reliant on limited borehole data, especially in terms of demonstrating spatial changes. Integration of GPR data with ground temperature measurements from boreholes and the use of Drone-based DEM during data processing provided a holistic perspective on the evolving nature of permafrost borders, significantly enhancing the accuracy and reliability of the findings.Comprehending spatial and temporal variations in permafrost borders is critical for predicting the impacts of climate change and guiding geotechnical and environmental management strategies. This research serves as a valuable reference for future studies aiming to explore permafrost conditions in polar regions, offering a comprehensive framework for more effective monitoring and management practices.
Interpretable multiscale Machine Learning-Based Parameterizations of Convection for ICON
Authors: Heuer Helge , Schwabe Mierk , Gentine Pierre , Giorgetta Marco A. , Eyring Veronika
Published: March 2024

In order to improve climate projections, machine learning (ML)-based parameterizations have been developed for Earth System Models (ESMs) with the goal to better represent subgrid-scale processes or to accelerate computations by emulating existent parameterizations. These data-driven models have shown success in approximating subgrid-scale processes based on high-resolution storm-resolving simulations. However, most studies have used a particular machine learning method such as simple Multilayer Perceptrons (MLPs) or Random Forest (RFs) to parameterize the subgrid tendencies or fluxes originating from the compound effect of various small-scale processes (e.g., turbulence, radiation, convection, gravity waves). Here, we use a filtering technique to explicitly separate convection from these processes in data produced by the Icosahedral Non-hydrostatic modelling framework (ICON) in a realistic setting. We use a method improved by incorporating density fluctuations for computing the subgrid fluxes and compare a variety of different machine learning algorithms on their ability to predict the subgrid fluxes. We further examine the predictions of the best performing non-deep learning model (Gradient Boosted Tree regression) and the U-Net. We discover that the U-Net can learn non-causal relations between convective precipitation and convective subgrid fluxes and develop an ablated model excluding precipitating tracer species. We connect the learned relations of the U-Net to physical processes in contrast to non-deep learning-based algorithms. Our results suggest that architectures such as a U-Net are particularly well suited to parameterize multiscale problems like convection, paying attention to the plausibility of the learned relations, thus providing a significant advance upon existing ML subgrid representation in ESMs.
Emulating Land-Processes in Climate Models Using Generative Machine Learning
Authors: Clyne Graham
Published: March 2024

Recent advances in climate model emulation have been shown to accurately represent atmospheric variables from large general circulation models, but little investigation has been done into emulating land-related variables. The land-carbon sink absorbs around a third of the fossil fuel anthropogenic emissions every year, yet there is significant uncertainty around this prediction. We aim to reduce this uncertainty by first investigating the predictability of several land-related variables that drive land-atmospheric carbon exchange. We use data from the IPSL-CM6A-LR submission to the Decadal Climate Prediction Project (DCPP). The DCPP is initialized from observed data and explores decadal trends in relationships between various climatic variables. The land-component of the IPSL-CM6A-LR, ORCHIDEE, represents various land-carbon interactions and we target these processes for emulation. As a first step, we attempt to predict the target land variables from ORCHIDEE using a vision transformer. We then investigate the impacts of different feature selection on the target variables - by including atmospheric and oceanic variables, how does this improve the short and medium term predictions of land-related processes? In a second step, we apply generative modeling (with diffusion models) to emulate land processes. The diffusion model can be used to generate several unseen scenarios based on the DCPP and provides a tool to investigate a wider range of climatic scenarios that would be otherwise computationally expensive. 
Decentralising Europe's Energy Systems: Diverse Perspectives in National Roadmaps
Authors: Ozhan Serhat
Published: March 2024

As the European Union (EU) progresses towards an energy transition to mitigate climate change, the concept of decentralization has attained increasing prominence as a potential pathway. This study conducts a systematic comparative analysis of decentralization conceptualizations within the pivotal National Energy and Climate Plans (NECPs) for 2030 and Long-Term Strategies (LTSs) out to 2050. Textual analysis of 28 NECP and 24 LTS documents surfaces 313 mentions of “decentralization”, revealing multiplicity across member states’ outlooks regarding strategic decentralization prioritizations and definitions.While technical dimensions of localized renewables and distributed infrastructure predominate, particular member states delineate decentralization’s transformative breadth more expansively—entailing substantial disruptions to conventional centralized paradigms across social, political and economic dimensions. Appreciable divergence also emerges regarding motivations, spanning improved resilience, efficiency and environmental performance. Inter-temporal comparisons expose profound integration of governance and participation considerations in LTSs, contrasting NECPs’ emphases on technical and financial aspects.Notably, France's 2023 NECP draft indicates a potential reversal towards re-centralization - lowering renewable targets and contemplating extended nuclear reliance. Such outliers highlight complex interplays between national circumstances and priorities amidst the bloc’s overarching decentralizing course.As ascending decentralization restructures Europe’s energy paradigm, these findings furnish insights into member states’ transitional outlooks, trends and intricacies. This informs governance to facilitate coherent, cooperative decarbonization aligned with decentralization’s multifaceted essence and diverse national manifestations.
Difference in seasonal variation between airborne prokaryotic and eukaryotic communities in Ny-Ålesund, Svalbard
Authors: Uetake Jun , Tobo Yutaka
Published: March 2024

The Arctic region is undergoing rapid environmental changes due to global climate warming. Among the Arctic regions, the surface temperature in the northern Barents Sea, where the Svalbard archipelagos are located, has increased more significantly than in other areas over the last 40 years. This warming results in the loss of sea ice in the ocean and glacier ice in terrestrial areas. These changes in surface conditions may impact the emission of bioaerosols from the Earth's surface, which play a crucial role in ecosystem dynamics and cloud formation. However, there is still limited temporal monitoring in Svalbard and also in entire Arctic. Therefore, in this study, we focus on assessing the temporal changes in bioaerosols during the summer to autumn season in Ny-Ålesund, Svalbard using DNA metabarcoding approaches.Bioaerosol samples were collected using a vacuum pump with a flow rate of 40 LPM onto HEPA-style filters at the outdoor observatory of the Veksthuset building in Ny-Ålesund. Filters were replaced every 24-72 hours from July to November 2022. Those were then preserved in DNA storage medium (DNA/RNA shield) and transported to the laboratory under frozen conditions. Following particle concentration and DNA extraction, we amplified and sequenced three DNA metabarcoding regions (16S, 18S, and ITS) using the MiSeq platform (Illumina).Seasonal variations in the observed number of Amplicon Sequence Variants (ASVs) from each barcoding region reveal distinct patterns. These patterns are characterized by elevated ASV counts during the summer (ITS and 18S) and autumn (16S). Microbial communities within the 16S region at the phylum level remain relatively stable throughout the entire season. Conversely, communities within the 18S and ITS regions undergo significant changes in mid-September and after October, coinciding with the terrestrial area being covered by seasonal snowpack. In the presentation, we will provide a more detailed explanation of community changes at the ASV level and discuss the distinctive seasonal patterns observed.
Exploring the Outline of the Pre-Odra River System Through Seismic Reflection Imaging Offshore Rügen Island
Authors: Schmidt Maryse C. , Hübscher Christian , Seidel Elisabeth , Preine Jonas , Haimerl Benedikt
Published: March 2024

Understanding the course and dynamics of ancient river systems, such as the pre-Odra, is crucial for unravelling the geological history of regions like the southern Baltic Sea, providing valuable insights into the post-glacial evolution of landscapes and riverine processes. We will present marine reflection seismic and acoustic data from three research cruises on the research vessel ALKOR that allow us to investigate the pre-Odra river system in the southern Baltic Sea. Our analysis focuses on the region off the east coast of the island Rügen. This region corresponds to the suspected location of the pre-Odra river system, which was situated during the post-glacial phase approximately 9,000 - 14,500 years BP off Rügen. The seismic reflection data indicate that the sediment infill of the pre-Odra is charged by shallow gas of presumably biogenic origin. Since the seismic gas indicators correspond with the pre-Odra where its location has been determined by previous geological studies, we use gas lineaments as a proxy for the braided paleo-river bed. This study refines and extends the known fluvial extent of the Odra river system by 60 km, tracing it north towards the Tromper Wiek, indicating its terminus in the Baltic Sea close to eastern to Rügen.
Effect of salinity on the preservation of organic matter in the terrestrial-aquatic interface.
Authors: Samantaray Santrupta , Sanyal Prasanta
Published: March 2024

Coastal terrestrial-aquatic interfaces are critical for carbon sequestration and "blue carbon" burial, but their vulnerability to climate change is a concern. Against the backdrop of climate change, the emergence of irregular rainfall patterns and intensifying heat waves undoubtedly influence the physicochemical characteristics of numerous terrestrial-aquatic interfaces. This study focuses on the response of organic matter (OM) to a short-term failure of the northeast monsoon (NEM) in the 2018 drought event, which was the worst in 150 years that transformed the Pulicat Lagoon into a hypersaline system. We investigated the impact of elevated salinity on OM through δ13C and δ15N analyses of bed sediments and suspended solids. Additionally, long-term NEM deficit events (for 10 years) and their effect on the preservation of OM are also investigated in sub-surface sediments by using bulk carbon isotopes and compound-specific isotope analysis (CSIA) of plant-derived n-alkanes and fatty acids in short sediment cores (depth of 70cm) derived from the euhaline, metahaline, and hypersaline salinity gradients. We observed that, despite hypersaline conditions, substantial OM concentrations persisted in suspended solids post-NEM, indicating resilient autochthonous production. Key mechanisms driving productivity include cation exchange, wind-induced re-suspension, and fishing-induced seagrass-detritus dislodgment. Nevertheless, the bulk carbon isotopic compositions of subsurface sediments across different salinity regions exhibit complexities due to mixed OM sources and overlapping isotopic values of autochthonous and allochthonous origins. Among the plant biomolecules, n-alkanes and fatty acids are preserved in bed sediments with CPI values > 1. However, the carbon isotopic complexities of n-alkyl compounds in subsurface sediments reveal that the preservation mechanism is not uniform across different salinity regions. Notably, n-alkyl compounds in hypersaline sub-surface sediments have CPI values consistently <1 compared to euhaline and metahaline regions where CPI values are >1, attributed to bacterial transformations and anaerobic fatty acid reduction. Prolonged hypersaline conditions and anoxia not only affected the distribution patterns but also elevated the isotopic differences between fatty acids and n-alkanes (δ13CFA-ALK values) in the hypersaline region, underscoring the need for careful consideration when using these compounds as paleo-vegetational proxies. This study contributes to understanding the intricate interplay between salinity, OM dynamics, and isotopic variations in coastal terrestrial-aquatic interfaces, enhancing our insights into their responses to changing climatic conditions.
A New Method for Finding SEP Event Onset Times and Evaluating Their Uncertainty: Poisson-CUSUM-bootstrap Hybrid Method
Authors: Palmroos Christian , Dresing Nina , Gieseler Jan
Published: March 2024

Solar energetic particles (SEPs) are highly energetic charged particles that have their origin of acceleration in strong space-weather driving phenomena that the Sun produces, e.g., solar flares and coronal mass ejections. These particles pose a radiation hazard to both technological equipment and living organisms in space, which is why the nature of these events is an important subject of study in the modern age where space technology is being applied more and more every day.An SEP event is the result of a burst of SEPs arriving at an observer. Especially the onset time of an SEP event at varying energies is a key piece of information in relating the in-situ particle measurements to the remote-sensing observations of solar eruptions. Accurate knowledge of the onset time is an indispensable requirement for identifying the acceleration mechanisms and the source of the energetic particles. What traditional methods lack, however, is the assessment of the uncertainty related to the onset time.Our method employs a unique combination of a statistical quality control scheme, Poisson-CUSUM, coupled with statistical bootstrapping. By choosing random samples from the background intensity preceding an SEP event and varying the integration time of the data, the method is able to produce a set of distributions of possible onset times. From this set of distributions we extract the most probable onset time and uncertainty intervals relating to this set of distributions. The uncertainty of onset times in a range of different energies is also in a direct connection to the uncertainty of a derived path length and inferred solar injection time of the particles, two extremely important pieces of information that velocity dispersion analysis yields, which is yet another motivator behind developing the method presented hereThis research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004159 (SERPENTINE). 
Transfer of the nitrogen isotope signature from the nitrate pool to the diatom biomass and into the diatom frustule
Authors: Studer Anja S. , Baan Jochem , Lehmann Moritz F.
Published: March 2024

The nitrogen (N) isotopic composition of diatom frustule-bound organic matter (δ15NDB) from sedimentary archives has been used as a promising proxy indicator to reconstruct nitrate utilization in the high-latitude oceans on different timescales. The advantage of this proxy over conventional N isotopic approaches, such as measuring δ15N values of the bulk sediment, is that δ15NDB is thought to be protected from diagenetic alteration and bacterial degradation. Despite the fact that the δ15NDB proxy has been applied in palaeoceanographic research for two decades, little is known about the propagation of the δ15N signature of assimilated nitrate into biomass δ15N and subsequently into δ15NDB, and to what extent N-isotope fractionation during frustule-bound N synthesis varies among species and with environmental conditions. Only few δ15NDB data exist for living diatoms in natural environments or laboratory cultures, and implications for paleo-environmental reconstructions appear controversial between existing studies. Here, we present novel constraints on the relationship between δ15N values of nitrate, diatom bulk biomass, and diatom frustule-bound N across samples from different natural environments and from controlled mono-specific diatom cultures. While previous ground-truthing work has focussed on marine diatom species both in culture and in the ocean, we extend our study to freshwater species and lacustrine environments. We find that, in mono-specific diatom cultures, δ15NDB values are generally relatively close to biomass δ15N values, irrespective of the variable 15N-fractionation imparted by nitrate assimilation. Similarly, analysis of diatom samples from natural environments revealed little offset between δ15NDB and bulk biomass δ15N values in samples that are near mono-specific. By contrast, in more mixed-species samples, δ15NDB values can be shifted in both directions relative to biomass δ15N values, possibly as a result of i) species-specific N isotope fractionation during frustule-bound N synthesis, and/or ii) non-uniform contribution of N to the total biomass and diatom-bound N pools between different species.
Bridging Carbon and Water Dynamics: Insights from Process-Based Modeling in Agricultural Ecosystems Under Global Change Drivers
Authors: Kanagarajah Lucas , Reitz Thomas , Schädler Martin , Taubert Franziska , Vogel Hans-Jörg , Weller Ulrich , König Sara
Published: March 2024

Global change drivers, such as climate change and land-use intensification, pose imminent threats to the functioning of agricultural ecosystems, by disrupting vital ecosystem processes. In this context, understanding the interplay between carbon cycling and ecohydrological processes becomes important for the development of adaptive strategies that enhance the resilience of agricultural ecosystems in response to the dynamic challenges imposed by global change drivers. Process-based simulation models are a powerful tool to disentangle the complex interactions of microbiota-plant-soil interactions and provide a basis for long-term predictions and scenario simulations.Our study focuses on the "Global Change Experimental Facility (GCEF)" (https://www.ufz.de/index.php?en=42385), where comprehensive data on plant physiology, soil nutrients, soil microbes, fauna, soil structure and moisture were collected across various agricultural land-use types. These include conventional and organic cropping systems, intensively and extensively farmed meadows, and extensively grazed sheep pastures, all under ambient and simulated future-climate conditions.Here we present an extended version of the process-based soil model BODIUM, which captures the dynamics of soil functions, responding to soil management or changes in climatic conditions. The model was parametrized for different land-use types on the GCEF. First simulation results, compared with measured data for validation, reveal promising agreement in carbon data for cropland systems. However, an overestimation of water content within the soil profile after the vegetation phase needs further investigation. Additional simulations, alongside experimental findings are employed to discuss the impact of climate-change and land-use types on carbon and water dynamics and their potential interactions. The successful validation of the model across varied treatments provides the foundation for a potential application of the model to other boundary conditions that are not covered by the GCEF experiment.
Climate conditions control the SOC sequestration potential of agricultural terraces
Authors: Zhao Pengzhi , Fallu Daniel , Cucchiaro Sara , Pears Ben , Lang Andreas , Tarolli Paolo , Doetterl Sebastian , Whitaker Jeanette , Brown Tony , Van Oost Kristof
Published: March 2024

Agricultural terraces, being among the volumetrically largest and most common man-made landforms, have been widely implemented to support essential soil ecosystem services, e.g., erosion control, soil nutrient, and water retention, and have had an essential impact on soil organic carbon (SOC) stock and its exchange with the atmospheric C. However, the direction and magnitude of this impact remain highly uncertain. By integrating the broad-scale field observations of 14 terrace sites across the EU with a global data synthesis, we demonstrate that the effectiveness of terracing-driven SOC sequestration potential is intricately controlled by climate conditions that govern in-return soil properties.Our findings reveal that the terracing practices represent a promising land management strategy for enhancing SOC sequestration, but also that risks of SOC loss exist when building terraces under arid climate, where they could be potentially very beneficial to crop productivity and SOC storage. We recommend that future terrace construction should integrate water and nutrient recycling techniques to ensure soil moisture and nutrient availability, enhancing land productivity and maximizing SOC sequestration potential. Our data suggest that promoting the recovery of the lost topsoil C during terrace construction through increasing C inputs and C use efficiency, i.e., straw return and nutrient amendment is an efficient way to counteract initial SOC losses.
Mapping large-scale deep soil moisture variation using ambient seismic noise
Authors: Lu Yang , Wang Qing-Yu , Bokelmann Götz
Published: March 2024

Soil moisture is a key metric to assess soil health. Water held in the shallow subsurface between soil particles enables various biogeochemical and hydrological processes indispensable to soil functions. Potential soil moisture deficit may raise the irrigation demands, which further exacerbates the stress on the water supply. The changes in soil moisture can impact climate, further amplifying the climatic anomalies and intensifying extreme weather events. Thus, understanding soil moisture and its dynamics over time are of broad scientific interest and practical implications.Despite the vital importance of soil moisture, it still lacks sufficient means to properly assess the parameter at a regional scale, which is an essential research dimension for addressing practical issues in the agricultural and environmental sectors. Ambient noise seismology provides new possibilities to infer subsurface changes in a real-time, non-intrusive, and costless manner.In this study, we map the temporal variations in soil moisture for Central-Southern Europe with ambient seismic noise. It is the first time that the seismic method has been applied to map soil moisture at a regional scale using an ordinary seismic network setup. The method helps in bridging the resolution gap between current pointwise (e.g., tensio-, electrical- and neutron-meter) and global (e.g., satellite-based remote sensing) investigations, providing complementary information for both scientific research and public decision-making. 
Green barriers to plastic transport in rivers: an indoor study
Authors: Di Lollo Giovanni , Gallitelli Luca , Adduce Claudia , Maggi Maria Rita , Trombetta Beatrice , Scalici Massimiliano
Published: March 2024

Every day, millions of tons of plastic debris are poured into rivers from industrial and civil waste or due to social carelessness and transported to the ocean. Here they decompose into small fragments, compromising the health and growth of fauna and flora that ingest or absorb them. In recent years the idea of using vegetation to trap and extract plastic waste has developed to limit this phenomenon. The aim of this work is to experimentally quantify the ability of aquatic vegetation in trap plastic and understand whether different biotic factors, hydraulic conditions or debris type influence it. Three of the most abundant macrophytes in European and Asian rivers are tested in this study, Myriophyllum spicatum, Potamogeton crispus and Phragmites australis. Natural samples of vegetation, taken along the Tiber, Ninfa-Sisto and Aniene rivers, are positioned into a recirculating flume, where the flow rate and the water depth can be varied. Once stationary flow conditions are reached, a known quantity of polystyrene fragments of different sizes (macroplastics, mesoplastics and microplastics) is added in the upstream part of the channel. The ratio between the fragments retained in the green barrier and the total added during the experiment defines the species' capacity to retain plastics. A change in seasonality, simulated by changing the water depth and the number of stolons inserted into the flume, is tested and its effects on the trapping efficiency is analysed. Three plant’s densities and two water depths are tested for each species. All three plant species show to effectively retain large and medium-sized plastic debris. Only the Myriophyllum spicatum, whose needle-like leaves form a denser network than the other two species, is also found to be efficient in retaining microplastics. The density of the area occupied by vegetation affects the number of trapped fragments, which increases for all species as the number of inserted stolons increases. The change in water depth has no significant impact on the results obtained. In conclusion, the three macrophyte species analyzed in this work can be used to create a barrier to the transport of plastics from rivers to oceans. A more complex structure of the vegetation allows the trapping of microplastics. A larger density of the area occupied by vegetation induces larger trapping efficiency, while hydraulic conditions appear to have no significant influence for the values tested in this study.
Estimating severe low flows on human-influenced catchments by combining weather generator, analogue spatial disaggregation, and hydrological modelling under historical and future climate.
Authors: Devers Alexandre , Gailhard Joël , Parey Sylvie , Froidurot Stéphanie
Published: March 2024

Understanding and quantifying severe low flows is crucial for the management of hydropower or thermal power plants. Moreover, low flows are strongly related to the climatic regime and will be affected by climate change. Therefore, we propose a modelling chain to estimate severe low flow values for several human-influenced catchments in France, both under current and future climate.Firstly, a bivariate weather generator (Touron, 2019) of daily temperature and precipitation, representing the average of 28 catchments spread out over France, was trained, and used to generate 1000 meteorological time series over a 30-year period. Average daily precipitation and temperature are then spatially disaggregated to produce 1000 local time series for each of the 28 catchments using an analogue approach. Thirdly, MORDOR-SD a lumped conceptual rainfall-runoff model, developed and used at EDF (Garavaglia et al. 2017), combined with upstream-downstream propagation and water management module was forced by the 1000 local meteorological time series. The resulting 1000 time series of simulated river flows are then used to calculate an empirical rare percentile estimate of low flows across 12 large catchments of interest.The methodology is applied on historical period (1981-2010) using precipitation and temperature observations to train the weather generator. The robustness of the method is evaluated by comparing return levels of low flows obtained through the proposed method and the ones estimated through river flow observations available. Finally, to assess the impact of climate change, the weather generator is also trained/used with 5 downscaled climate projections from the CMIP5 experiments corresponding to: (1) the historical period (1981-2010) and, (2) 4 storylines representing different levels of warming/drying (2036-2065).The comparison over the historical period has shown the relative agreement between simulated and observed severe low flows. Furthermore, under future conditions, the climatic differences between the 4 storylines lead to logical differences in the estimation of severe low flows, i.e. warmer/drier storylines lead to lower estimation of severe low flows.
Structural Study of the Taibai Pluton in the Qinling Orogen, Central China: Implications for Relationship between Tectonics and Granite Magmatism
Authors: Yan Shan , Li Yang , Tao Wei , Liu Yuanyuan , Liu Fule
Published: March 2024

The Qinling Orogen, as the most prominent mountain belt in the central part of China, has experienced multiple tectonic-magmatic thermal events. Abundant granitoids were developed in response to the tectonic regime transformation during Mesozoic. These granitoids serve as valuable indicators to reflect the process and dynamic mechanism of the orogeny, as their growth process hold important structural information about the tectonic evolution. Although some geochronological and geochemical data exist from this region, it lacks systematic and sufficient tectonomagmatic information to develop a regionally coherent and viable geodynamic model for the Mesozoic magmatic evolution of the Qinling Orogen.This study strategically focuses on the Mesozoic Taibai pluton in the Qinling Orogen, aiming to investigate the relationship between tectonics and magmatism and their variation in time and space during Mesozoic. Through multiscale structural analysis and geochronology methods, we have delineated three deformation phases, with representative rock samples reflecting mid-high temperature deformation conditions, evident in both microscopic observations and EBSD analysis, The quartz’s dynamic recrystallization and c-axis fabric analysis revealed that the Houzhenzi Shear Zone (HSZ, south of the Taibai pluton) experienced deformation under green-schist facies conditions at ∼400–550 °C. The results of Anisotropy of Magnetic Susceptibility indicate that the HSZ deformed in response to pure shear-dominated transpression and top-to-NW shear sense, exhibiting two superimposed phases of shear deformation. Together with previously published data, our results concluded the relationship between the Taibai pluton and the structural features of shear zones. The research indicates that the Qinling Orogen was dominated by compressional tectonics during the Late Mesozoic, Taibai pluton was obliquely extruded under the influence of surrounding shear zones. This research contributes to a more comprehensive understanding of the complex processes involved in continental tectonics and magmatic evolution. This work was financially supported by NSFC projects (grants 4217020371, 4180020120).
Extreme cold events in Europe under a reduced AMOC
Authors: Corti Susanna , Meccia Virna Loana , Simolo Claudia , Bellomo Katinka
Published: March 2024

There is a consensus that a weakened Atlantic Meridional Overturning Circulation (AMOC) decreases mean surface temperature in the Northern Hemisphere, both over the ocean and the continents. However, the impacts of a reduced AMOC on cold extreme events have not yet been examined. We analyse the impacts of a reduced AMOC strength on extreme cold events over Europe using targeted sensitivity experiments with the EC-Earth3 climate model. Starting from a fully coupled ocean-atmosphere simulation in which the AMOC was artificially reduced, a set of atmosphere-only integrations with prescribed sea surface temperature and sea-ice cover was conducted to evaluate the effects of weakly and strongly reduced AMOC strength. Despite overall cooling, reduced AMOC leads to fewer winter cold spells in Europe. We find that the weakened AMOC intensifies near-surface meridional gradient temperature in the North Atlantic and Europe, thus providing the energy to boost the jet stream. A stronger jet stream leads to less atmospheric blocking, reducing the frequency of cold spells over Europe. Although limited to the output of one model, our results indicate that a reduced AMOC strength may play a role in shaping future climate change cold spells by modulating the strength of the jet stream and the frequency of atmospheric blocking.