bluuebunny/crossref_metadata_2025 huggingface dataset:
Global observations of an up to 9 day long, recurring, monochromatic seismic source near 10.9 mHz associated with tsunamigenic landslides in a Northeast Greenland fjord
Authors: Koelemeijer Paula , Widmer-Schnidrig Rudolf , Svennevig Kristian , Hicks Stephen , Forbriger Thomas , Lecocq Thomas , Mangeney Anne , Hibert Clément , Korsgaard Niels , Lucas Antoine , Satriano Claudio , Anthony Robert , Mordret Aurélien , Schippkus Sven , Rysgaard Søren , Boone Wieter , Gibbons Steven , Cook Kristen , Glimsdal Sylfest , Løvholt Finn ,   VLPGreenland team
Published: March 2024

We report the discovery of an unprecedented, monochromatic low-frequency seismic source arising from the fjords of North-East Greenland. Following a landslide and tsunami event in Dickson fjord on 16 September 2023, the seismic waves were detected by broad-band seismometers worldwide. Here we focus on a detailed analysis of the long-period seismic signal, while a reconstruction of the dynamics of the landslide is presented by Svennevig et al. in session NH3.5. Both frequency and phase velocity of the waves are consistent with fundamental mode Rayleigh- and Love-waves. However, the decay rate of these waves is much slower than predicted for freely propagating surface waves so that we infer a long-lasting and slowly decaying source process. Although the 16 September 2023 event was by far the largest, analysis of historical seismic data has revealed five other previously undetected events, all with a fundamental frequency between 10.85 and 11.02 mHz. The signal of the largest two events initially decayed with a quality factor, Q close to Q=500, which increased to Q=3000 within the first 10 hours and could thus be detected for up to nine days. The smaller four events had a slow decay-rate (Q>1000) for their entire duration. In comparison, the global average attenuation of Rayleigh waves at these frequencies is Q=117 for PREM, thus precluding a single, impulsive source for these signals.Gleaning archives of optical and SAR satellite images reveals that at least four out of six events could be associated with landslides in Dickson fjord, the two others remain unresolved. However, such rapid transient events cannot explain the long duration of the radiated seismic waves. Our modelling of the largest event shows that a transversal seiche in Dickson fjord, excited by a landslide induced tsunami, can account for both the monochromatic low frequency signal as well as its seismic signal amplitude and radiation pattern. However, the seiche modelling results in Q values lower than 250 and hence the seiche needs to be continuously driven for the entire duration of the observed seismic signal. Thus, a full understanding of the source process that produces the monochromatic signal remains enigmatic.
The Dynamics of Levantine Intermediate Water in the Mediterranean Sea: A Comprehensive Study of Spatial and Temporal Evolution, Climate Change Signals, and Ecosystem Impact.
Authors: Geara Batoul , Testor Pierre , Conan Pascal , Durrieu De Madron Xavier , Fakhri Milad , Bosse Anthony
Published: March 2024

The Levantine Intermediate Water (LIW) plays a crucial role in the Mediterranean thermohaline circulation, significantly influencing the regional climate and ecosystems through mixing with under- and above-lying waters.  Our study aims to explore the spatial and temporal evolution of LIW, tracing the journey of this water mass from its formation in the Levantine Basin to its arrival in the western Mediterranean Sea. While previous studies have confirmed some aspects of the evolution of the LIW along its trajectory, our approach stand out by using an extensive in situ database composed by a compilation of different data sets, extending on the entire Mediterranean Sea. This dataset incorporates CTD profiles from ship cruises, gliders, floats, and XBT measurements during 2018-2023 period. This data will be used to map LIW pathways and dispersion patterns, to offer insights into its interactions with neighboring water masses. Furthermore, our investigation focuses on LIW's evolution over years, with a specific emphasis on identifying signals of climate change in particular areas. Preliminary findings indicate notable shifts in LIW properties, encompassing temperature, salinity, and nutrient content, hinting at potential climate-induced alterations.  These observations contribute significantly to our understanding of the broader implications of climate change on Mediterranean water masses and ecosystems.
Estimation of water level time series for lakes and rivers using SWOT KaRIn measurements 
Authors: Schwatke Christian , Scherer Daniel , Dettmering Denise
Published: March 2024

For more than three decades classical satellite altimetry has been successfully used to monitor water levels of inland waters such as rivers, lakes and reservoirs. In December 2022, a new generation of altimeter mission called Surface Water and Ocean Topography (SWOT) was successfully launched. SWOT is equipped with a classical radar nadir altimeter comparable to Jason-3, but also with a new Ka-band Radar Interferometer (KaRIn). KaRIn uses the principle of SAR interferometry, which has the capability to monitor almost every inland water body worldwide because of its swath. 

In this contribution, we present a new approach to derive water level time series for lakes and rivers using the high-resolution SWOT pixel cloud dataset. This dataset allows us to monitor water levels of very small lakes (> 100m²). We use SWOT data measured on the fast sampling orbit (03/2023 – 07/2023, 1-day repeat cycle) and the science orbit (since 07/2023, 21-day repeat cycle). For quality assessment, the resulting water level time series will be validated with in-situ data. All water level time series will be freely available on the web portal of the "Database of Hydrological Time Series of Inland Waters" (DAHITI, https://dahiti.dgfi.tum.de). 

 
Tracking the dynamics of paddy rice cultivation practice through MODIS time series and PhenoRice algorithm.
Authors: Luintel Nirajan , Ma Weiqiang , Ma Yaoming , Wang Binbin , Xu Jie , Dawadi Binod , Mishra Bhogendra , Dorigo Wouter
Published: March 2024

Monitoring paddy rice cultivation is essential for ensuring food security and for land resource management in agrarian countries of South Asia. In this presentation, we investigate the spatial and temporal variation of rice cultivated area and phenological metrics in Nepal between 2003 and 2018 using the time series MODIS data and PhenoRice algorithm (Luintel et al., 2021). Comparisons of PhenoRice outputs with ancillary data show that implementation of PhenoRice with the MODIS data can be used for long-term change analysis of rice cultivation. Results on spatial distribution illustrate that rice cultivation is concentrated in the low elevation belt in the south of Nepal. The phenological mapping shows that the cultivation begins earlier in the western region compared to the eastern region and begins earlier in the hilly region compared to the plains. The inter-annual trend analysis found a statistically significant decrease of rice cultivated area at the rate of 19130 hectares per year after 2008, and the loss of rice fields was more prominent in the eastern plains while rice farming expanded in the mid-hills in the western region. Our study provides insights regarding timely and cost-efficient monitoring of rice farming at a large scale in a mountainous region. 

Luintel, N, Ma, W., Ma, Y, Wang, B. Xu, J., Dawadi, B., Mishra, B. (2021). Tracking the dynamics of paddy rice cultivation practice through MODIS time series and PhenoRice algorithm. Agricultural and Forest Meteorology, 307, 108538. https://doi.org/10.1016/j.agrformet.2021.108538 
Rift inheritance in a fold-and-thrust belt evolution: Central Apennine crustal balanced cross-section
Authors: Maresca Augusto , Granado Pablo , Muñoz Josep A. , Manatschal Gianreto , Ogata Kei , Tavani Stefano
Published: March 2024

The Apennines fold-and-thrust belt builds part of the Africa-Eurasia convergent plate boundary. It developed due to the Neogene subduction of the Alpine Tethys underneath Europe and to the subsequent involvement of the Adria microplate rifted margin into the collisional process. Since the Miocene, eastward retreat of the slab caused extensional deformation of the thrust pile, eventually leading to the opening of the Tyrrhenian back-arc basin. Multiple schools of thought exist about the structural style of the Apennines, each of which proposes rather irreconcilable models. The amount of shortening, the involvement of the crystalline basement, the architecture of the inherited rifted system with its degree of reactivation during convergence, and the role played by compressive inheritance during back-arc extension, are still under discussion.In this contribution we focus on the crustal structure of the central Apennines, along a transect that stretches from the Sardinian shelf (West) to the center of the Adriatic Sea (Est). Our aim is to critically evaluate prior models and contextually to illuminate the deeper part of the belt, which is still seldom considered in modern-day Central Apennines solutions. Based on the most recent ideas on rift inheritance and thrust tectonics, we present a brand-new crustal balanced cross-section. We employ well-constrained surficial geological data from available public maps, as well as the most recent deep-reaching geophysical data (especially, tomography and seismological data), which are supplemented by thermochronological, biostratigraphic, and Sr-isotope datings. On top of that, data are encompassed in a coherent geodynamic framework that is supported by a geometrically balanced and consistent kinematic model. This way, we provide a comprehensive explanation for the regionally observed coupled forward migration of compressional and extensional domains, which is related to the slab pull/trench retreat system.Our results point to a predominantly thin-skinned style for the orogen with a secondary basement involvement in the later collisional stage. Inherited extensional faults, developed during the Mesozoic rifting of Adria, were partially reactivated during convergence, and influence spacing and geometry of the compressional features. The main thrusts of the area are characterized by significant displacements, ranging from 10 to >50 km, and sole out into a basal décollement located at the base of the post-Variscan sedimentary sequence. Finally, post-thrusting back-arc extension is accommodated by faults that either displace the compressional décollement levels or reactivate them with an opposing kinematics.
IRISCC: supporting society’s capacity to address and strengthen resilience to climate change risks 
Authors: Rinne Janne , Brus Magdalena , Nikolaidis Nikolaos , Bäck Jaana , Laj Paolo , Kutsch Werner , Schaap Dick , Steenberg Larsen Klaus , Phillippin Sabine , Petracca Altieri Rosa , Lund Cathrine , Vendelboe Katrine , Haapanala Päivi , Virkki Säde , Kivekäs Niku , Sorvari Sundet Sanna
Published: March 2024

Anthropogenic climate change, driven by elevated levels of greenhouse gases, is accelerating at an unprecedented rate, causing significant changes in climatic and biogeochemical conditions. The adverse effects of climate change include detrimental impacts on natural and managed ecosystems, as well as on socio-economic systems, human health, and welfare. Recognising the urgent need to address these challenges, the IRISCC (Integrated Research Infrastructure Services for Climate Change Risks) project aims to provide scientific and knowledge-based services to support societal adaptation to climate change. The project is funded by the European Union under grant agreement No 101131261 (HORIZON Research and Innovation Actions in Research Infrastructure Programme topic HORIZON- INFRA-2023-SERV-01-01) and has over 70 partners providing research services.For the researchers focusing on climate change risks, IRISCC will offer services, such as open data and access to research platforms via transnational access and virtual access programs. Here IRISCC employs an integrated approach to understanding climate change risks, encompassing hazards, exposure, and vulnerability. By fostering interdisciplinary collaboration, the project strives to support science enabling all users of IRISCC services to better predict, mitigate, and adapt to climate-related risks affecting human and natural systems. The project's overarching mission is to facilitate in-depth knowledge production on climate change risks and accelerate the translation of scientific knowledge into innovative solutions.The IRISCC consortium comprises expertise from several research infrastructures, covering domains such as Earth systems, health and environment, and social sciences, each bringing in their research service portfolios. Through inter- and transdisciplinary approaches, the project aims to provide transnational and virtual access to cutting-edge research, innovation, training, and digital services. In summary, the IRISCC project aligns with the session's focus on systems thinking approaches, presenting a comprehensive strategy supporting users to tackle the interconnected issues of climate-related hazards, risks, and impacts. The commitment of the project to provide integrated research infrastructure services positions it as a key player in advancing our ability to predict, mitigate, and adapt to the multifaceted challenges posed by climate change in European regions and cities.
Linking global-scale mantle flow with diapir-like coronae formation
Authors: King Scott
Published: March 2024

Coronae are crown-like, tectono-volcanic features found on Venus that typically range in diameter from 100-700 km. Diapirs of warm upwelling material impinging on the lithosphere are often invoked to explain coronae formation. With more than 500 coronae identified on the surface of Venus, if these diapirs are individually linked to a mantle plume, Venus must have a very different mantle structure than Earth. I consider three cases designed to assess the potential relationship between large-scale, long-wavelength lower mantle structure and smaller-scale upper mantle structure that could potentially form diapirs consistent with those that are envisioned to interact with the lithosphere and form coronae. I use the geoid and topography to identify the large-scale pattern of convection because the geoid contains and integral of the temperature anomalies over the depth of the mantle. Plume tails—narrow vertical conduits—integrate to give a positive geoid anomaly while small-scale, time-dependent drips or upwellings are minimized in the depth integration. The first case—the reference case—has a small, stepwise decreases in viscosity between the lower mantle (1022 Pa s), transition zone (1021 Pa s), and upper mantle (5x1020 Pa s) with no phase transformations. This led to 20 ~1000-km diameter mantle plumes that remained stationary for more than 1.5 Gyr. This calculation is consistent with a number of geophysical observations it does not support the formation of coronae by plume-lithosphere interaction. To decouple the lower and upper mantle, I further decrease both the upper mantle and transition zone viscosities to 1020 Pa s while leaving all other parameters unchanged. In this calculation the same 20 ~1000-km diameter mantle plumes formed and remained stationary for more than 1.5 Gyr. The geoid and topography are anti-correlated, inconsistent with the observed values on Venus and, the spatial scale, number, and topographic evolution of the plumes are not consistent with coronae. This calculation does not support the formation of coronae by plume-lithosphere interaction. In an attempt to further decouple the upper and lower mantle I add an endothermic phase transformation at the ringwoodite-bridgmanite boundary in addition to the decreased upper mantle and transition zone viscosities while leaving all other parameters unchanged. Unique to this calculation, a very large number of ~100-km diameter small topographic upwellings form some associated with the large-scale geoid high but never associated with the large-scale geoid low. The inclusion of a phase transformation decoupling the upper and lower mantle has the potential to create diapir-like structures in the upper mantle consistent with coronae formation.
Benefits of fully focused SAR altimetry to coastal wave height estimates: A case study in the North Sea
Authors: Passaro Marcello , Schlembach Florian , Ehlers Frithjof , Kleinherenbrink Marcel , Dettmering Denise , Seitz Florian , Slobbe Cornelis
Published: March 2024

Estimating the three geophysical variables significant wave height (SWH), sea surface height, and wind speed from satellite altimetry continues to be challenging in the coastal zone because the received radar echoes exhibit significant interference from strongly reflective targets such as mud banks, sheltered bays, ships etc. Fully focused SAR (FF-SAR) processing exhibits a theoretical along-track resolution of up to less than half a metre. This suggests that the application of FF-SAR altimetry might give potential gains over unfocused SAR (UF-SAR) altimetry to resolve and mitigate smallscale interferers in the along-track direction to improve the accuracy and precision of the geophysical estimates. The objective of this study is to assess the applicability of FF-SAR-processed Sentinel- 6 Michael Freilich (S6-MF) coastal altimetry data to obtain SWH estimates as close as possible to the coast. We have developed a multi-mission FF-SAR processor and applied the coastal retracking algorithm CORALv2 to estimate SWH. We assess different FF-SAR and UFSAR processing configurations, as well as the baseline Level-2 product from EUMETSAT, by comparison with the coastal, high-resolution SWAN-Kuststrook wave model from the Deltares RWsOS North Sea operational forecasting system. This includes the evaluation of the correlation, the median offset, and the percentage of cycles with high correlation as a function of distance to the nearest coastline. Moreover, we analyse the number of valid records and the L2 noise of the records. The case study comprises five coastal crossings of S6-MF that are located along the Dutch coast and the German coast along the East Frisian Islands in the North Sea. We find that the FF-SAR-processed dataset with a Level-1b posting rate of 140 Hz shows the greatest similarity with the wave model. We achieve a correlation of ~0.8 at 80% of valid records and a gain in precision of up to 29% of FF-SAR vs UF-SAR for 1- 3 km from the coast. FF-SAR shows, for all cycles, a high correlation of greater than or equal to 0.8 for 1-3 km from the coast. We estimate the decay of SWH from offshore at 30 km to up to 1 km from the coast to amount to 26.4%+-3.1%. 
Landscape-scale And Spatially Explicit Representation of vegetation dynamics and ecosystem carbon stocks in a hyperdiverse tropical forest ecosystem (LASER)
Authors: Hofhansl Florian , Hietz Peter , Huber Werner , Weissenhofer Anton , Wanek Wolfgang
Published: March 2024

Tropical vegetation dynamics and ecosystem carbon (C) stocks typically vary with local topography and forest disturbance history. Yet, neither remote sensing nor vegetation modeling captures the underlying mechanistic processes determining ecosystem functioning and therefore the resulting estimates often do not match field observations of vegetation C stocks, especially so in hyperdiverse tropical forest ecosystems. This mismatch is further aggravated by the fact that multiple interacting factors, such as climatic drivers (i.e., temperature, precipitation, climate seasonality), edaphic factors (i.e., soil fertility, topographic diversity) and diversity-related parameters (i.e., species composition and associated plant functional traits) in concert determine ecosystem functioning and therefore affect tropical forest C sink-strength.Here, we propose a novel framework designed for integrating in-situ observations of local plant species diversity with remotely sensed estimates of plant functional traits, with the goal to deduce parameters for a recently developed trait- and size-structured demographic vegetation model. Plant-FATE (Plant Functional Acclimation and Trait Evolution) captures the acclimation of plastic traits within individual plants in response to the local environment and simulates shifts in species composition through demographic changes between coexisting species, in association with differences in their life-history strategies.Our framework may be used to project the functional response of tropical forest ecosystems under present and future climate change scenarios and thus should have crucial implications for assisted restoration and management of tropical plant species threatened by extinction.
The Role of Tropical Cyclone on Changjiang RiverSubaqueous Delta Geomorphology: A Numerical Investigationof Tropical Cyclone Danas (2019)
Authors: Tang Bixuan , Zhang Fan , Jia Jianjun , Feng Zhixuan , Tang Jieping , Xing Fei , Wang Yaping
Published: March 2024

Subaqueous deltas are facing growing threats of erosion. Tropical cyclones (TCs), which arepredicted to affect mid-latitude estuaries more frequently with higher intensity in the future, can play animportant role in subaqueous delta geomorphology change. Nevertheless, direct in situ measurement ofTC-induced bed elevation change (BEC) was rarely reported before. In this study, four tripods were deployedat different parts of the Changjiang River subaqueous delta (CRSD) to capture BEC during TCs in July2019. Rapid erosion (20 mm day −1 ) during TC Danas (2019) was observed by high precision bed elevationmeasurement, over 10 times faster than that during calm weather conditions. Moreover, the recorded rates ofBEC varied substantially among these stations. A coupled three-dimensional wave-current-sediment model wasthen developed for the CRSD to help understand the spatial variability of observed BEC. The model resultsshowed two striking features of BEC during TC Danas: (a) enhanced sediment accretion near the sharp bottomsalinity front offshore of the north channel; (b) marked erosion near the front of CRSD. Further analysis showedthat the converging bottom currents in concert with enhanced sediment resuspension during TC Danas led tosignificant convergence of sediment flux near the bottom salinity front. In addition, the diverging isobaths alongthe front of the CRSD resulted in the onshore deviation of bottom current and diverging sediment flux underthe downwelling-favorable winds of Danas. Many TCs in the CRSD generate similar downwelling-favorablewinds and currents, growing TC threats in the future may therefore exacerbate erosion in this region.
Investigation of the Suess effect in the South-West Indian Ocean over the last two decades – A model-data study
Authors: Waelbroeck Claire , Leseurre Coraline , Buchanan Pearse J. , Reverdin Gilles , Metzl Nicolas , Racapé Virginie , Lo Monaco Claire , Pierre Catherine , Demange Jérôme , Fin Jonathan
Published: March 2024

Measurements of dissolved inorganic carbon (DIC) concentration and its isotopic composition (δ13CDIC) are essential to study chemical and biological processes involved in the ocean carbon cycle, including photosynthesis, respiration, and air-sea CO2 fluxes. Anthropogenic CO2 emissions from fossil fuel combustion have caused an increase in DIC accompanied by a decline in δ13CDIC (called the Suess effect). δ13CDIC is thus a useful tracer to assess the oceanic uptake of anthropogenic CO2.Annual assessments of the Global Carbon Budget (e.g. Friedlingstein et al., 2023) have revealed a growing deviation over the last 10 to 15 years between the estimates of the ocean carbon sink based on observations and models, with the growth of the observation-based ocean CO2 sink being larger compared to the models. Discrepancies in the multi-decadal trend originate from all latitudes but are greatest in the Southern Ocean.Here, we present DIC and δ13CDIC measurements from surface and water column samples collected in the South-West Indian Ocean during repeated summer cruises over the last two decades (1998-2021) conducted on board the RV Marion Dufresne within the French monitoring program OISO (Océan Indien Service d’Observation). We compare these measurements with the DIC and δ13CDIC simulated over the same period by the δ13C-enabled version of the NEMO-PISCES ocean-biogeochemical model.We use different methods to separate the natural and anthropogenic signals over the last 20 years. Our analysis reveals some inconsistencies between simulated and observed DIC and δ13CDIC, as well as between other simulated and observed biogeochemical parameters, whereas physical parameters are generally well reproduced by the model. Identifying the cause for this mismatch bears the potential to explain all or part of the divergence between the observation-based and model-based estimates of oceanic carbon uptake.
Uncertainties too large to predict tipping times of major Earth system components
Authors: Ben Yami Maya , Morr Andreas , Bathiany Sebastian , Boers Niklas
Published: March 2024

Observations are increasingly used to detect critical slowing down (CSD) in potentially multistable components of the Earth system in order to warn of forthcoming critical transitions in these components. In addition, it has been suggested to use the statistical changes in these historical observations to extrapolate into the future and predict the tipping time. We argue that this extrapolation is too sensitive to uncertainties to give robust results. In particular, we raise concerns regarding (1) the modelling assumptions underlying the approaches to extrapolate results obtained from analyzing historical data into the future, (2) the representativeness of individual time series representing the variability of the respective Earth system components, and (3) the effect of uncertainties and preprocessing of the employed observational datasets, with focus on non-stationary observational coverage and the way gaps are filled. We explore these uncertainties both qualitatively and quantitatively for the Atlantic Meridional Overturning Circulation (AMOC). We argue that even under the assumption that these natural systems have a tipping point that they are getting closer to, the different uncertainties are too large to be able to estimate the time of tipping based on extrapolation from historical data.
How ice anisotropy contributes to fold and ice stream in large-scale ice-sheet models
Authors: Zhang Yu , Bons Paul D. , Sachau Till , Franke Steven
Published: March 2024

Satellite and airborne sensors have provided detailed data on ice surface flow velocities, englacial structures of ice sheets and bedrock elevations. These data give insight into the flow behaviour of ice sheets and glaciers. One significant phenomenon observed is large-scale folds (over 100 m in amplitude) in the englacial stratigraphy in the Greenland ice sheet. A large population of folds is located at ice streams, where the flow is distinctly faster than in the surroundings, such as the North-East Greenland Ice Stream (NEGIS). While there is no consensus regarding the formation of large-scale folds, unraveling the underlying mechanisms presents significant potential for enhancing our understanding of the formation and dynamics of ice streams.Ice in ice sheets is a ductile material, i.e., it can flow as a thick viscous fluid with a power-law rheology. Furthermore, ice is significantly anisotropic in its flow properties due to its crystallographic preferred orientation (CPO). Here, we use the Full-Stokes code Underworld2 (Mansour et al.,2022) for 3D modelling of the power-law and transversely isotropic ice flow, also in comparison with the isotropic ice models.Our simulated folds with anisotropic ice show complex patterns on a bumpy bedrock, and are classified into three types: large-scale folds (fold amplitudes >100 m), small-scale folds (fold amplitudes
Comparing ERA5 and model data to observations for wind resource assessment – a case study from Tanzania 
Authors: Chamberlain-Clay Alexander , Thompson Elisabeth
Published: March 2024

The ERA5 reanalysis is established as a key source of gridded wind-speed information for much of the world, having better performance and higher resolution (30km) than other reanalysis products. It’s used as a source of truth for driving wind-power models, and verifying ML predictions, especially in the absence of observational measurements. However, verification of ERA5 has mostly focused on Europe and the northern hemisphere, not examining performance in low-observation regions such as East Africa, where wind power investment and green energy provision is crucial to climate goals. As part of the FOCUS-AFRICA project, this study investigates how well the ERA5 reanalysis represents the climatology of 19 different observation sites in Tanzania and compares them to 3 CORDEX-Africa models driven by ERA-Interim at a similar resolution to ERA5, and one convection-permitting 4.4km resolution model (CP4A). ERA5 is shown to perform poorly at representing inland wind climatologies in Tanzania, with Perkins skill scores of 0.21-0.62 (1 is perfect), in comparison to European inland stations showing an average a score of ~0.8 in previous studies. This is caused by underestimations of mean wind speed compared to observations for inland sites.  The CP4A model performs best with scores of 0.54-0.79, despite the fact this model is not forced by real-world conditions.These results show the need for caution when using ERA5 as a basis for any wind resource assessment or model validation. It also indicates that wind resource in East Africa may be underestimated, which would have negative impacts on investment decisions in the region. 
Parameter optimization of an agro-ecological model for regional NUTS-3 yield data
Authors: Wold Olga , Baatz Roland , Berg-Monicke Michael , Rezaei, Eyshi Ehsan , Nendel Claas
Published: March 2024

Climate change increasingly affects agricultural systems in Central Europe, necessitating the development of robust forecasting models for drought, heat, and fire events (DHF). These hazards pose significant threats to crop production and require proactive measures to enhance resilience and adaptation.This research project is dedicated to constructing a thorough framework for forecasting DHF events in Central Europe. It integrates an agro-ecosystem model aimed at examining how crops respond, particularly when it comes to water availability. The focus of this research extends to the region's awareness to climate-related threats and the robustness of its agricultural systems.We utilize the MONICA (Model for Nitrogen and Carbon in Agriculture) crop model to simulate crop growth and response across a spectrum of environmental conditions. The MONICA model is designed to represent the complexity of crop development, considering factors such as soil properties and weather variations. MONICA model has the capacity to explore various scenarios, including heat stress and drought sensitivity, providing a comprehensive view of how crops respond to these challenges. The used data includes high-resolution meteorological (1km resolution, daily), topographic, historical crop records and soil information for whole Germany. The dataset covers the past two decades, encompassing vital information such as crop yield records.By sensitivity analysiswe systematically identified key parameters influencing simulated crop yield and above ground biomass, particularly in the context of drought and heat stress. These insights are invaluable for advancing our understanding of how crops respond to environmental stressors.Moving forward, our focus shifts to the calibration and optimization routines to quantify specific parameter sets for individual NUTS-3 regions within Germany.In the poster presentation, we look forward to sharing the newest findings from our ongoing research on advanced calibration tools and yield simulations conducted over Germany. Simulation results are compared to observed yield data, providing valuable insights into the effectiveness and real-world applicability of the modelling approaches.
Relating bush encroachment density of savanna soils in the Kalahari district in Botswana to soil organic matter stocks and quality.
Authors: García de Castro Barragán José María , Batisani Nnyaladzi , Pule-Meulenberg Flora , Akanyang Lawrence , de la Rosa Arranz José María , Reinoso Limones M. Rocio , Knicker Heike
Published: March 2024

Bush encroachment is a form of rangeland degradation. It is characterized by a shift from herbaceous to woody plant dominance, which has reduced indigenous plant and animal biodiversity and it’s a significant problem in southern African savannas, particularly in Botswana, Namibia and South Africa. Overgrazing by cattle on the one hand and the loss of a large part of large herbivores on the other hand, have been identified as main contributor to imbalance of this delicate ecosystem. The present study aimed to investigate bush encroachment effects on soil organic matter (SOM) in areas of low, medium, and high bush density in a farmed area of the Botswana’s savanna. Bush encroachment is expected to have significant effects on soil properties. It is assumed to decrease soil organic C concentration as well as contents of macro and micro nutrients. To investigate such possible impacts, a sampling was realized during the dry season in various plots with varying encroachment densities (Senegalia mellifera). The analysis included standard soil parameters, (pH, electrical conductivity, cation exchange capacity; elemental composition, and bulk density) the composition of the SOM was characterized by solid-state nuclear magnetic resonance spectroscopy. The preliminary results of these analysis revealed only small differences between sites with low, medium, and high levels of bush encroachment. This suggests that the impact of bush encroachment on savannah’s SOM is lower than expected and may not be directly related to bush density. Further research will compare the obtained data with data obtained during the wet season to obtain a better understanding of the SOM dynamics and the impact of encroachment on soil degradation.Acknowledgement: The authors would like to express their gratitude to the European Commission for the financial support of this research within the European Framework Program for Research and Innovation Horizon 2020 (Grant No. 101036401).
Water use efficiency and carbon use efficiency response differently to greening on the Loess Plateau in China
Authors: Wang Yue , Gao Guangyao , Huang Yanzhang , Wang Zhuangzhuang
Published: March 2024

Water use efficiency (WUE) and carbon use efficiency (CUE) in dryland ecosystems are highly sensitive to complex climate and CO2 changes, which may cause imbalance between carbon and water cycles in terrestrial ecosystems. However, the mechanism of the systematic effects of multiple factors on WUE and CUE remains unclear. Here, we examined the trends in WUE and CUE in China’s Loess Plateau during 2001-2020 and assessed the underlying drivers using PML_V2 products and satellite-based data by employing the spatial random forest (SRF) method. Our analysis identified a significantly increasing trend in WUE and a slightly downward trend in CUE. In space, NDVI was the most important factor affecting the spatial variation of WUE and CUE, but WUE had a significant positive response to NDVI, while CUE had a significant negative response to NDVI. Precipitation and CO2 concentration were the most important environmental factors driving spatial variability in WUE and CUE, respectively. However, vapor pressure deficit was the most important factor driving CUE annual variation controlling most areas of the greening region. Our research revealed that despite the improvement in water utilization, the greening of vegetation did not enhance carbon sequestration potential in the Loess Plateau. Furthermore, we demonstrated that vegetation was the most important factor causing WUE spatiotemporal variation and CUE spatial variation, while atmospheric drought inhibiting vegetation growth was the most important factor causing CUE temporal variation, reflecting the interactivity and complexity of the driving factors behind the spatial and temporal variability of WUE and CUE. Our study provides new insights into the driving characteristics of WUE and CUE spatiotemporal variability and enhances the knowledge of how the carbon-water coupling process induced by vegetation greening responds to environmental changes in arid and semi-arid regions in the backdrop of climate change, contributing to ecological restoration practices and sustainable management in the dryland.
Measurement of the Composition of the Local Interstellar Cloud with the Interstellar Probe Mission
Authors: Wurz Peter , Fausch Rico , Gasser Jonathan , Galli André , Vorburger Audrey , Brandt Pontus , Barabash Stas
Published: March 2024

The proposed Interstellar Probe (IP) spacecraft of NASA will travel through the heliosphere and advance into the local interstellar medium (LISM) within roughly 16 years, i.e., at twice the speed as the Voyager spacecraft. IP will enable the dedicated exploration of the heliospheric boundary by imaging the heliosphere from inside and outside the heliopause, and by directly sampling the unknown LISM. IP will also enable in situ measurements in the undisturbed LISM beyond the heliospheric bow shock or bow wave. The measurement of the chemical composition of the neutral gas in the local interstellar cloud is an important element of the scientific investigations of IP. So far, the chemical composition of the LISM was mostly inferred from pickup ions in the solar wind, from anomalous cosmic rays, and from spectroscopic observations of nearby stars. We are designing a highly specialized mass spectrometer to measure the neutral gas of the LISM in situ at these extremely low densities. The expected species to be recorded are H, He, C, N, O, Ne, Na, Mg, Al, Si, P, S, Ar, Ca, and Fe. This list of species allows to derive astrophysical important element ratios, like the Ne/O ratio. In addition, this mass spectrometer will measure the isotope composition of D/H, 3He/4He, 22Ne/20Ne, and 36Ar/38Ar of the LISM with unprecedented accuracy. These measurements will take advantage of the long duration of the IP mission, allowing for long integration times. The design of the instrument will be presented, together with estimated signals, and the operation scenario for the 50-year IP mission.
Geothermal Heat Flow Mapping of Germany: Multi-Geophysical and Geological Data Inversion and Associated Uncertainties
Authors: Sobh Mohamed , Christiansen Rodolfo , Al-Aghbary Magued , Gabriel Gerald
Published: March 2024

In geothermal resource assessment, terrestrial heat flow is a crucial metric, providing key insights into lithospheric thermal states and energy balance, with significant implications for geology, geophysics, and geodynamics. This study focuses on modeling geothermal heat flow (GHF) in Germany, where direct borehole temperature gradient data is limited, i.e. only 595 unevenly distributed published heat flow points exist.To address this data scarcity, our approach utilizes indirect methodologies for GHF estimation. We integrate various geophysical and geological datasets, including gravity, magnetics, upper mantle velocity structure, topography, crustal and lithospheric thickness, fault distribution, proximity to volcanoes, and compositional data. This multi-faceted approach allows us to overcome the spatial constraints inherent in single-data reliance and more accurately reconstruct measured heat flow, e.g. in comparison to classical curie depth estimations.Given the complexities in direct geophysical and geological data representation, our project utilizes a probabilistic, multi-geophysical inversion method. This not only enhances our understanding of Germany's geothermal potential but also allows for a detailed quantification of uncertainties.We have developed a new heat flow map with a high resolution. This map more accurately and effectively illustrates the terrestrial heat flow distribution in the study area, providing a more detailed depiction than previous interpolation results. Our preliminary results have successfully identified high heat flow zones in regions such as the Rhenish Massif, Molasse Basin, and Upper Rhine Graben.
Scaling relations between leaf and plant water use efficiencies in rainfed Cotton – Role of environmental and biophysical parameters
Authors: Chintala Syam , karimindla Arun rao , kbvn Phanindra
Published: March 2024

Water use efficiency (WUE) relates two important processes of the plant atmosphere continuum namely net carbon assimilation (via photosynthesis) and water utilization (via evapotranspiration). Our desire to trade-off WUE between accurate measurement at leaf level (WUEL) and effective implementation at plant level (WUEP) demands accurate scaling relations. Conventional mid-day, fully expanded, single-leaf measurements of WUEL are found to be poorly correlated with WUEP, thus questioning the applicability of scaling relations. This research is aimed at obtaining optimal time-window and leaf canopy position to characterize and upscale WUEL for effective field level implementation. Leaf gas exchange parameters were monitored in a rainfed Cotton field at five canopy positions for one crop cycle, and further correlated with WUEP considering individual measurements as well as their spatial averages. Optimal time-window showing highest correlation with WUEP has occurred during 15:00 to 16:00 hours irrespective of canopy leaf position and growth stage. Deviation with mid-day measurements of WUEL low during boll bursting stage (7.38 ± 4.69 %) and high during germination and seedling emergence stage (17.27 ± 5.37 %). These changes are largely attributed to stomatal regulation of water vapour via unregulated water stress conditions. Scaling relations between WUEL and WUEP are linear with correlation strengths ranging from 0.52 (west bottom) to 0.80 (plant top). At leaf level, WUE is controlled by variations in photosynthetic photon flux density (ρ = 0.80) and vapour pressure deficit (ρ = 0.78), whereas at plant level, WUE is controlled by relative humidity (ρ = 0.77) and net solar radiation (ρ = 0.85). Our findings can help in developing alternate water management strategies to improve WUE in rainfed Cotton fields of tropical humid climate.
Aerosol-Cloud-Precipitation Interactions in the Arctic: Insights from the ARTofMELT Campaign
Authors: Haberstock Lea , Asplund Julia , Neuberger Almuth , Ickes Luisa , Freitas Gabriel , Mattsson Fredrik , Baumgardner Darrel , Riipinen Ilona , Zieger Paul
Published: March 2024

Aerosol-cloud interactions play a crucial role in the Arctic’s radiative budget. During the campaign ‘Atmospheric rivers and the onset of sea ice melt’ (ARTofMELT 2023) we aimed to improve our understanding of aerosol-cloud interactions by conducting in-situ measurements of microphysical and chemical properties of aerosols, cloud droplets, and precipitation in the Arctic during the onset of sea ice melt. A ground-based fog and aerosol spectrometer (GFAS) and a fog monitor (FM-120) from Droplet Measurement Technologies (DMT) were used to measure among other things droplet size, number concentration, and liquid water content. Precipitation was measured with a meteorological particle spectrometer (MPS, DMT). Throughout the campaign, we observed several fog and blowing snow events, along with occasional precipitation. These events provided an opportunity to investigate and compare the distinctive microphysical properties associated with each event. Our findings reveal significant variations in the size distribution and particle phase of blowing snow, precipitation, and fog.
Climate variability in the atmospheric moisture supply during meteorological drought episodes over La Plata Basin
Authors: Porfírio da Rocha Rosmeri , Drumond Anita , de Oliveira Marina , Stojanovic Milica , Nieto Raquel
Published: March 2024

This study aims to analyze variations in atmospheric moisture supply from major remote Brazilian hydrological basins during meteorological drought episodes in the La Plata Basin (LPB). The analyses were conducted for the period 1980-2018, using a Lagrangian diagnostic methodology that estimates the contribution of atmospheric moisture to the water balance in the region. The method relies on the Lagrangian model FLEXPART integrated with ERA-Interim reanalysis data. The technique calculates the difference between evaporation and precipitation by computing temporal variations in specific humidity of air parcels identified over the major Brazilian basins along their trajectories forward in time towards the LPB. During the analysis period, a total of 49 meteorological drought episodes were identified over the LPB through the time series of the monthly SPEI-1 (Standardized Precipitation-Evapotranspiration Index). Linear regression analysis indicates a relationship between variations in atmospheric moisture supply by air parcels traveling from several basins (Amazon, North Atlantic, and Tocantins) and the duration, severity and peak of drought episodes over LPB. This implies that more severe, longer, and higher peak dry episodes in the LPB were associated with a decrease in atmospheric moisture supply from the air parcels traveling from these basins. 
Surface Mass Balance of the Antarctic Megadune Plateau
Authors: Bursztynowicz Jacek , Savarino Joel , Daviet Benjamin , Ginot Patrick , Le Meur Emmanuel , Gautier Elsa , Witwicky Julien , Jong Lenneke , Spolaor Andrea , Stenni Barbara
Published: March 2024

The East Antarctic Plateau contains particular areas with megadunes and wind-glazed surfaces, exhibiting distinct patterns of snow accumulation and its variability over time and space. Despite its significance for sea levels, ocean circulation, and weather patterns, knowledge about snow accumulation in these areas remains limited. Several ice cores, coming from diffrent parts of Plateau, were drilled during the East Antarctic International Traverse (EAIIST).Using volcanic horizons as time markers, coupled with ground-penetrating radar (GPR) measurements, we intend to reconstruct the surface mass balance (SMB) of the megadune plateau in both time and space for the last ca. 2000 years where accumulation is largely unknown. In a first step, geochemical profiles of the different cores were analyzed. A critical analysis is first conducted to find the best marker of the volcanic eruptions between the electrical conductivity, the total sulfur concentration and the sulfate profile. Based on this critical analysis, a common volcanic-dating scale is proposed for the different drilling sites. However, the megadune areas show a strong disturbed layering accumulation with clearly visible ablated layers, making the volcanic identification a true challenge.  Work is currently underway to use volcanic cryptotephra and electron microprobe analysis to unambiguous determine the volcanic tie-point identification. In a subsequent step, GPR data will be process to spatialize the accumulation information. Matching radar internal layers with well-dated ice core reference layers will allow for dating and deducing the surface mass balance over time for the entire EAIIST transect.