bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel insight into spatio-temporal variability of storm events for modelling hydrological processes at catchment scale based on machine learning
Authors: Zubelzu Sergio , Cuevas Blanca , Sanz Ernesto , Almeida Andrés , Tarquis Ana
Published: March 2024

Hydrological processes are shaped by complex and distant processes characterised by high spatio-temporal variability. Being the first hydrological process, triggering the remaining ones, precipitation, or more precisely, storm events, have paramount importance on the subsequent evolution of the hydrological system. The spatio-temporal evolution of precipitation has received profound attention from scientists. This topic is commonly addressed in practical hydrological simulation by simple (pseudo) deterministic algorithms as form example Polygons of Thiessen or Krigging methods. In this work we present a novel approach based on two pillars: first by focusing on storm events instead of in aggregated precipitation values and second by spatially analysing the relationships among the recorded values aided by machine learning algorithms. With that aim we have retrieved precipitation records from 6 weather stations in Madrid city with hourly latency from January 2019 and 587 stations with 15 minutes latency from January 2004. We have extracted the observed storm events in any case and analysed the spatio-temporal patterns underlying the storm evolution thus observing the scarce representativity of the traditional methods being machine learning approaches better suited for providing representative data. This work is part of the project TED2021-131520B-C21, supported by the MCIN/AEI/10.13039/501100011033 and the European U nion “NextGenerationEU”/PRTR.
Reservoir compaction during and after fluid production: A case study of the Groningen Gas Field
Authors: Hangx Suzanne , Pijnenburg Ronald , Shinohara Takahiro , Jefferd Mark , Mehranpour Mohammad Hadi , Spiers Christopher
Published: March 2024

Prolonged hydrocarbon production often leads to subsidence and seismicity in offshore and onshore hydrocarbon fields. In the Netherlands, tens of centimetres of subsidence has occurred above the Groningen Gas Field, with widespread induced seismicity during the 60+ years of its lifetime. These phenomena are driven by reservoir compaction at depth, resulting from gas extraction. Modelling the reversible, elastic component of compaction is straightforward. However, permanent deformation can also occur, the rate and effects of which are very poorly constrained. Furthermore, from smaller fields in the vicinity, it has already become clear that compaction may continue even now that production has stopped in 2023. To be able to confidently forecast the long-term surface impact of fluid production, for fields such as Groningen, and many other fields around the world, models are required that include the physical mechanisms responsible for reservoir compaction. These mechanisms are still poorly known and quantified at true reservoir conditions. Combining microstructural observations, obtained from field material and experimental work, and novel experimental mechanical data, obtained at simulated stress changes relevant to the reservoir, enabled us to identify the main grain-scale deformation mechanisms operating in the reservoir sandstone of the Groningen Gas Field. A key role is played by the thin intragranular clay layers present between the quartz grains making up the load-bearing framework. Compaction of and slip along these thin clay films has accommodated the permanent deformation accumulated during the production stage. After production is halted, experiments suggest that slow, time-dependent grain breakage will start to play a role as well. Microphysical models describing rate-insensitive compaction were implemented in Discrete Element models to assess sandstone compaction behaviour at the cm-dm scale. These numerical models can be used to evaluate reservoir compaction in different locations on the field due to pressure equilibration or repressurisation, with rate-sensitive mechanisms, such as stress corrosion cracking, to be added at a later stage, as their descriptions are still be developed. Eventually such small-scale numerical models should form the basis to upscale the sandstone behaviour to the reservoir scale.
FOCA: a new quality-controlled collection of floods and catchment attributes in Italy
Authors: Claps Pierluigi , Evangelista Giulia , Ganora Daniele , Mazzoglio Paola , Monforte Irene
Published: March 2024

In recent years, various national databases of geomorphoclimatic watershed attributes have been released. Relevant examples are the CAMELS datasets for countries such as the United States, Australia, Chile, Brazil, Switzerland, France, Germany, and the United Kingdom (now integrated into Caravan), and LamaH-CE. This work introduces FOCA (Italian FlOod and Catchment Atlas), a national-scale collection of 631 Italian basins that we fully characterized by providing more than 100 attributes related to geomorphology, soil, land cover, NDVI, climate, and extreme precipitation. The basins reported in FOCA are derived from a national-scale inventory of peak floods and annual maximum daily floods named "Catalogo delle Piene dei Corsi d'acqua Italiani", realized thanks to a data rescue initiative performed by merging recent data, already available in digital format, with historical information available on printed documents.The selection of descriptors that we included in FOCA followed three main criteria: a) national spatial coverage; b) absence of regional or local distortions; c) adequate spatial resolution. Preference was given to local sources, resorting to global data only in specific cases. The inclusion of basin boundaries will allow users to assess additional descriptors using their models or datasets.FOCA stands out from other national datasets due to its robust collection of geomorphological descriptors, computed using the r.basin algorithm of GRASS GIS and subjected to thorough quality controls. Another distinctive feature is the incorporation of extreme rainfall characteristics, evaluated using station data instead of reanalysis data — deviating from the approach often seen in the development of CAMELS datasets. For this purpose, the Improved Italian - Rainfall Extreme Dataset (I2-RED) has been used. I2-RED is a national collection of rainfall extremes measured by more than 5000 rain gauges from 1916 up to the present that was developed as the outcome of a data rescue project.With this nationwide data collection, a wide range of environmental applications, with particular reference to flood studies, can now be undertaken on the Italian territory.
Introducing the Modern Ocean Sedimentary Inventory and Archive of Carbon (MOSAIC v.2.0) database and its initial applications
Authors: Paradis Sarah , Eglinton Timothy I.
Published: March 2024

Marine sediments play a crucial role in the global carbon cycle by acting as the gateway from short- to long-term reservoirs of both terrestrial and marine organic carbon (OC). To understand the spatiotemporal variability, sources, composition and reactivity of OC in marine sediments, a curated and harmonized database of OC content and associated parameters is needed, especially considering the logistical challenges and costs of retrieving samples at sea. This has prompted the development of the Modern Ocean Sediment Archive and Inventory of Carbon (MOSAIC) database. Here we present an updated version, MOSAIC v.2.0, which stores variables such as OC content, its isotopic composition (δ13C, Δ14C), sedimentological parameters (e.g., grain size, mineral surface area), and associated molecular signatures (e.g., lignin, fatty acid, alkane biomarkers). MOSAIC v.2.0 offers a broad spatiotemporal coverage, with data from more than 21’000 individual sediment cores collected since the 1950s, providing a key tool to assess the role of coastal and marine sedimentary organic carbon in the global carbon cycle. A new and interactive open-access web-interface to the database will be presented, along with Python and R packages that allow users to integrate MOSAIC in their data processing workflows. Finally, initial applications of MOSAIC (v.2.0) to understand spatial patterns in the geochemical composition of marine sediment on regional and global scales will also be illustrated.
Varying lake surface cover for reanalysis application
Authors: Choulga Margarita , Balsamo Gianpaolo , Boussetta Souhail , Kimpson Tom , Kurzeneva Ekaterina , Shevnina Elena , de Rosnay Patricia
Published: March 2024

Lakes modify the structure of the atmospheric boundary layer. They can intensify winter snowstorms, increase/decrease surface temperature and amount of precipitation. It has been shown that monthly varying lake surface cover has a significant positive impact over regions with prolong rain and dry seasons, especially over Malaysia, Indonesia and Papua New Guinea (see Kimpson et al., 2023).At European Centre for Medium-Range Weather Forecasts (ECMWF) current lake mask is constant over time and represent permanent water over the period 1984-2018. To meet reanalysis requirements of monthly varying high-resolution lake mask outlined in CERISE project the Joint Research Centre (JRC) Global Surface Water Explorer (GSWE) dataset (Pekel et al., 2016) was used. Applied methodology, its advantages and drawbacks, as well as first results of monthly lake surface cover maps will be presented.
Reassessing the pre-industrial air-sea carbon flux considering the ocean alkalinity budget
Authors: Planchat Alban , Bopp Laurent , Kwiatkowski Lester
Published: March 2024

Disparities in estimates of the ocean carbon sink, whether derived from global ocean biogeochemical models or from data products based on observations of surface ocean pCO2, question our ability to accurately assess ocean carbon uptake and its trend over recent decades. A potential factor contributing to the inconsistency between data products and model-based estimates is the pre-industrial air-sea carbon flux that is required to isolate the anthropogenic component from the total air-sea carbon flux estimated from observations. This pre-industrial air-sea carbon flux is thought to stem at the global scale from an imbalance between riverine carbon discharge to the ocean and sediment carbon burial.  Using a mass-balanced approach and comprehensive estimates of carbon inputs to the ocean by rivers and groundwater as well as carbon burial in marine sediments, Regnier et al. (2022) estimated that the pre-industrial ocean was outgassing 0.65 ± 0.30 petagrams of carbon per year. This updated estimation was used in the latest Global Carbon Budget (Friedlingstein et al., 2023) to derive an estimate of the ocean carbon sink over recent decades. In this study, we use a series of ocean biogeochemical pre-industrial simulations with varying assumptions related to carbon riverine input and burial to develop a theoretical framework to determine the ocean carbon outgassing and its spatial distribution. Building upon previous efforts, we integrate a carbon mass-balance approach with consideration of the ocean alkalinity budget. While conventionally assumed that the global alkalinity inventory was in equilibrium during the pre-industrial era — with riverine alkalinity discharge offset by CaCO3 burial — we demonstrate that an imbalance in the pre-industrial ocean alkalinity budget could significantly affect the carbon outgassing flux. This novel conceptual framework allows us to reestimate the pre-industrial carbon flux while considering the ocean alkalinity budget. Furthermore, it provides a simple method to reevaluate this flux in light of new assessments of carbon or alkalinity sources and sinks, while also covering their uncertainty ranges.
Signal separation in global, temporal gravity data using a multi-channel U-Net
Authors: Heller-Kaikov Betty , Pail Roland , Werner Martin
Published: March 2024

One big challenge in the analysis and interpretation of geodetic data is the separation of the individual signal and noise components contained in the data. Specifically, the global, temporal gravity data obtained by the GRACE and GRACE Follow-On satellite missions contain spatial-temporal gravity signals caused by all kinds of mass variations in the Earth’s system. While only the sum of all signals can be measured, for geophysical interpretation, an extraction of individual signal contributions is necessary.Therefore, our aim is to develop an algorithm solving the signal separation task in global, temporal gravity data. Since the individual signal components are characterized by specific patterns in space and time, the algorithm to be found needs to be able to extract patterns in the 3-dimensional latitude-longitude-time space.We propose to exploit the pattern recognition abilities of deep neural networks for solving the signal separation task. Our method uses a multi-channel U-Net architecture which is able to translate the sum of various signals as single-channel input to the individual signal components as multi-channel output. The loss function is a weighted sum of the L2 losses of the individual signals.We perform a supervised training using synthetic data derived from the updated Earth System Model of ESA. The latter consists of separate datasets for temporal gravity variations caused by mass redistribution processes in the atmosphere, the oceans, the continental hydrosphere, the cryosphere and the solid Earth.In our study, we use different parts of this dataset to form training and test datasets. In this fully-synthetic framework, the ground truth of the individual signal components is also known in the testing stage, allowing a direct computation of the separation errors of the trained separation model.In our contribution, we present results on optimizing our algorithm by tuning various hyperparameters of the neural network. Moreover, we demonstrate the impact of the number of superimposed signals and the definition of the loss function on the signal separation performance of our algorithm.
Distributed surface mass balance of the avalanche-fed Argentière glacier, French Alps
Authors: Kneib Marin , Dehecq Amaury , Gilbert Adrien , Basset Auguste , Miles Evan S. , Ducasse Etienne , Béraud Luc , Mouginot Jérémie , Mouginot Jérémie , Jouvet Guillaume , Laarman Olivier , Jourdain Bruno , Brun Fanny , Six Delphine
Published: March 2024

Avalanches are important contributors to the mass balance of glaciers located in mountain ranges with steep topographies. They result in localized mass inputs that are particularly difficult to quantify, due to the difficulty to access these avalanche cones in the field, and the need to account for ice dynamics when analyzing the elevation change signals from digital elevation models. Here, we aim to quantify the avalanche contribution to Argentière Glacier (Mont Blanc massif, French Alps) by inverting its distributed surface mass balance from remote sensing products and modeled ice thicknesses. Ultimately, we run the full-Stokes model Elmer-Ice with and without the additional contribution from avalanches to evaluate the importance of accounting for this process for future simulations of glacier evolution.We used Pléiades satellite stereo acquisitions, captured at a high temporal resolution (more than 2 acquisitions per year), to generate detailed maps of elevation change and velocity spanning the years 2012 to 2021. We derived the distributed ice thickness of the glacier using three models of varying complexity, constrained by a dense array of ground penetrating radar measurements. To account for the uncertainty in ice thicknesses, we perturbed the modelled thicknesses using sequential gaussian simulations. We then combined ice thickness and velocity to derive the distributed flux divergence and surface mass balance at 20 m resolution across the whole glacier, carefully accounting for the uncertainties following a Monte Carlo approach. We evaluated our results against long-term mass balance measurements from stakes conducted as part of the French glacier monitoring service GLACIOCLIM, and in situ measurements of submergence on one of the main avalanche deposits.There is a good agreement between our surface mass balance estimates and the stake observations (RMSE < 1.5 m.w.eq) for all ice thickness scenarios, even though ice thickness represents the most important source of uncertainty. Thus, the comparison of our distributed surface mass balance estimate with the mass balance gradient derived from the stake measurements allows us to 1) highlight the ability and potential of such an approach to provide robust estimates of distributed surface mass balance and 2) estimate the contribution of avalanches for Argentière Glacier with a relatively high accuracy. Notably, preliminary results show that the mass balance in avalanche-fed areas of the accumulation zone is approximately 2-10 times larger than in other areas at the same elevation.
Longshore sediment transport in the nearshore zone: role of tides
Authors: Nnafie Abdel , Verwaest Toon , Dujardin Arvid , Röbke Bjorn
Published: March 2024

Shoreline erosion presents a significant threat to coastal areas globally, highlighting the need for a thorough understanding of the underlying physical processes to formulate effective mitigation strategies (Luijendijk et al., 2018). Studies on shoreline evolution (Mutagi et al., 2022) often rely on empirical formulations to calculate longshore sediment transport induced solely by waves. However, the extent to which tides contribute to this transport, especially in meso- and macro-tidal coastal environments, remains poorly understood.This study, conducted as part of a research project (known as MOZES) funded by the Flemish government, aims to quantify the relative effects of tides on longshore sediment transport in the nearshore zone. To achieve this objective, an idealized model (known as Q2Dmorfo, Arriaga et al., 2017) and two complex numerical models (Scaldis-Coast and Flemco, Dujardin et al., 2023) are utilized. In the idealized model, wave- and tide-induced longshore sediment transports are computed using two analytical models inspired by the work of Longuet-Higgins (1970) and Southgate et al. (1989). The two complex models calculate longshore sediment transport by fully resolving the flow field, thereby considering tides, waves, and wind.Various scenarios are explored, forcing the models with tides and waves independently, as well as in combination. The study area selected for this research is the Belgian coastal zone, which is characterized by meso- to macrotidal conditions.ReferencesArriaga, J., Rutten, J., Ribas, F., Falqués, A., & Ruessink, G. (2017). Modeling the longterm diffusion and feeding capability of a mega-nourishment. Coastal Engineering, 121, 1 - 13. doi: 10.1016/j.coastaleng.2016.11.011Dujardin, A.; Houthuys, R.; Nnafie, A.; Röbke, B.; van der Werf, J.; de Swart, H.E.; Biernaux, V.; De Maerschalck, B.; Dan, S.; Verwaest, T. (2023). MOZES – Research on the Morphological Interaction between the Sea bottom and the Belgian Coastline: Working year 1. Version 4.0. FH Reports, 20_079_1. Flanders Hydraulics: AntwerpLonguet-Higgins, M. S. (1970). Longshore currents generated by obliquely incident sea waves: 1. Journal of Geophysical Research (1896-1977), 75 (33), 6778-6789. doi: 10.1029/JC075i033p06778.Luijendijk, A., Hagenaars, G., Ranasinghe, R., Baart, F., Donchyts, G., & Aarninkhof, S. (2018). The state   of the world’s beaches. Scientific reports, 8 (1), 6641.Mutagi, S., Yadav, A., Hiremath, C.G. (2022). Shoreline Change Model: A Review. In: Nandagiri, L., Narasimhan, M.C., Marathe, S., Dinesh, S. (eds) Sustainability Trends and Challenges in Civil Engineering. Lecture Notes in Civil Engineering, vol 162. Springer, Singapore. https://doi.org/10.1007/978-981-16-2826-9_64Southgate, H. N. (1989). A nearshore profile model of wave and tidal current interaction. Coastal Engineering, 13 (3), 219-245. doi: 10.1016/0378-3839(89)90050-1. Sedimentary Geology, 33(3), 195–216.
Sediment Dating of Fluvial, Lacustrine and Aeolian Systems in the Basin of the great Lakes, Western Mongolia
Authors: Frechen Manfred , Rahimzadeh Neda , Wolf Dennis , Lehmkuhl Frank
Published: March 2024

Luminescence and radiocarbon dating methods are mandatory to set up reliable chronological frameworks for sedimentary systems to reconstruct climate and environmental changes quantitatively through time. Our study area, the Basin of the Great Lakes in Western Mongolia is a key area to investigate sediment archives and sediment pathways under variable climates in this region including extreme continental climatic conditions.  Alluvial fans, beach bars and dune fields, partly interacting with each other, were sampled for luminescence dating in detail. In this study, a total of thirty-four samples were taken from a beach ridge sequence of Khyargas Nuur and tested using K-feldspar single aliquot (2.5 mm) pIRIR dating to overcome the problem of the dim signal of quartz. Furthermore, single grain dating was also conducted to address the problem of insufficient bleaching of the pIRIR signals. The preliminary established chronological framework indicates that the studied samples were mostly deposited during the Holocene and the results yielded a continuous decline of the lake level for most of the Holocene period. 
Cloud characterization for trace gas retrievals over snow using O2-O2 and oxygen B-band absorption
Authors: Fehr Lukas , Zawada Daniel , Degenstein Doug , Bourassa Adam
Published: March 2024

Geostationary measurements of trace gases provide valuable air quality data at unprecedented temporal scales. At high latitudes challenges begin to arise, such as lines of sight that stray from nadir, and (during winter) limited sunlight and pervasive snow cover. Motivated by the desire to fully take advantage of TEMPO (Tropospheric Emissions: Monitoring of Pollution) measurements over Canada, we investigate one of these issues: snow.A key challenge with measurements over snowy scenes is the similar reflectivity of snow and clouds. Trace gas algorithms rely on the contrast between surface and cloud reflectivities to estimate an effective cloud fraction which is necessary to characterize the light path for cloudy scenes. This snow-cloud ambiguity ultimately compromises the data quality, denying the opportunity to capitalize on the potential increase in surface sensitivity offered by the high reflectivity of snow. Here we present an algorithm that simultaneously uses O2-O2 and oxygen B-band absorption to extract cloud data for trace gas retrievals while reducing dependency on the surface-cloud reflectivity contrast.
Lander Induced Thermo-Elastic Noise at InSight Location on Mars
Authors: Kizhaekke Pakkathillam Sreejaya , Lognonne Philippe , De Raucourt Sébastien , Kawamura Taichi
Published: March 2024

Understanding the intricate thermal dynamics on Mars is crucial for accurate scientific measurements, particularly for seismological studies. The InSight Mission to study the interior structure and composition of Mars has recorded the Mars seismograms and in-situ data for the initial assessment of Mars' geothermal heat flow. Given that these measurements are obtained in close proximity to the lander at the surface, a primary concern is the presence of thermo-elastic noise, originating from fluctuations in solar radiation, within the collected data. Experiments such as those conducted by SEIS on Mars have specifically identified this phenomenon, detecting noise during the eclipse of Phobos (Stähler et al, 2020). While managing periodic temperature variations of instruments is feasible, challenges arise with other factors, such as those associated with moving shadows on the ground and solar radiation fluctuations. This implies that the presence of the lander will introduce thermal perturbations, causing alterations in both local surface and subsurface temperature measurements. These challenges necessitate numerical quantification due to difficulties in filtering them from the data. Hence, this study investigates first how the shadowing effect from the lander's structure and solar radiation variations impacts subsurface soil temperatures and consideration of this effect on the tilt recorded on the seismometers. We develop a 3D numerical model within Comsol Multiphysics 6.1 finite element package. The key element in adapting this model for use on Mars is accurately replicating the illumination conditions on the surface. Based on sub solar latitude and longitude derived using the JPL Horizons Ephemeris output, an illumination model is set at the instrument site for a desired duration. Unlike the Moon, where no atmospheric contribution affects temperature variations, Mars possesses a thin atmosphere that contributes to convective heat transfer. First, an analytical model is employed to find the transient solution of temperature at any given depth and time instances. The solution to the energy balance analysis determines the boundary conditions at the ground surface, which are then applied in the heat conduction equations governing subsurface temperature distribution.  The numerical temperature distribution output at an unperturbed location, far away from the lander is then compared with the analytical solution.  Once the 3D model is calibrated, the resulting temperature profiles can be utilized to assess the tilt of the seismometer feet and the sensitivity to additional solar radiation fluctuations. The findings suggest that the presence of a lander can exert substantial effects on the surrounding temperature environment under Martian conditions. This can introduce noise into the data collected by the seismometer, emphasizing the importance of accounting for and mitigating such influences in both the design and data analysis.
Sustainability and cultural heritage conservation: re-use of sand from deconstruction renders
Authors: Menéndez Beatriz , Yameogo Victor , Ghorbel Elhem
Published: March 2024

The European project SCORE (Sustainable COnservation and REstoration of built cultural heritage, GA 101007531) deals with a two-way assessment of impacts of the environment on materials and of materials on the environment. Indeed, climate conditions and atmosphere composition determine built cultural heritage (BCH) materials’ behaviour and, at the same time, BCH conservation processes (products and techniques) impact greenhouse gases emissions and then climate change.The objective of this work is to study the feasibility of recycling old mortars and plasters from an existing building to extract the sand with the aim of reusing it to produce new mortars for the renovation of the built heritage. Old mortars and plasters were mainly made with "natural" sands, generally alluvium and river sands, available near the site. These sources of sand may no longer be available or have become scarce. The use of different sands from the original ones in restoration plasters has consequences on the aesthetic properties of the new plasters applied during the renovation, which often requires the use of additives and dyes. To solve this problem, one possibility is to extract the original sand from deconstruction mortars, taken for example from renovation sites.We tested the proposed method on a site in Paris. Deconstruction mortars were crushed and the sand was recovered, characterized and used for the formulation of new mortars by adding lime and water. Washing methods with water and acid washing solutions have been tested in order to obtain sands free of debris and lime agglomerates. Citric acid was used because it presents good lime dissolution results and is quite easy to employ in restoration works. Microscopic observations were made to determine the effectiveness of each washing solution. Sands washed only with water show some remains of lime on the grain surfaces whereas washing the grains with citric acid solution (2 %) produces excellent results.In addition, mortars formulations with different grain size of recycled sands were made. These formulations consist of a mixture of recycled sand, water and an additive lime in equal proportions. Specimens of 4 x 4 x 16 cm were produced and their mechanical properties were measured at 28 days of age. During the maturation time, the samples are kept in an environment with constant humidity and temperature, to optimize the conditions of hydration, carbonation and maturation.The results obtained show that the mechanical properties of mortars made from recycled sand are acceptable and that these are intrinsically linked to the grain size and quality of the sands. The mechanical properties of mortars formulated with recycled sands of the right grain size are similar to those formulated with commercial natural sand. A large part of the recycled sand, after just washing with water, can be used in the formulation of new mortars with regard to standards and aesthetic properties.
Towards a comprehensive optical workflow for monitoring and estimation of water levels and discharge in watercourses
Authors: Grundmann Jens , Blanch Xabier , Kutscher André , Hedel Ralf , Eltner Anette
Published: March 2024

Coping with natural disasters such as floods places special demands on the emergency units. From the point of view of command-and-control operators, observations of watercourses are desirable in the event of flooding in order to obtain an accurate picture of the situation. Optical measurement methods using cameras offer thereby advantages as they do not require water contact and hence can be used safely. Therefore, the project "KIWA: Artificial Intelligence (AI) for Flood Warning" (http://kiwa.hydro.tu-dresden.de/) is developing AI-based tools for the robust quantification of water levels, flow velocities and flow rates from surveillance cameras.In this article, we present the workflow for an exclusive optical measurement of time series of water level and discharge from single images and short video sequences. The basis is a high-precision (i.e., at centimetre level), georeferenced 3D terrain model of the measurement site including the riverbed. The terrain model is created using the structure-from-motion (SfM) technique and georeferenced via ground control points (GCPs) measured with a multiband GNSS receiver. To determine the water level, the water area in the single images is automatically segmented using AI based on convolutional neural networks (CNNs) and then intersected with the terrain model. Changes of the camera geometry influence the measurement accuracy during long-term observations. Therefore, the GCPs are automatically detected in the individual images with an adapted AI-based keypoint detector to frequently update the estimated camera orientation. To estimate the discharge, the water surface flow velocity is determined using short video sequences and applying the particle tracking (PTV) method, whereby the segmented water area narrows down the search area for the particle detection. Afterwards, the "OptiQ" modelling approach is used to derive the discharge times series based on the PTV measurements. Thereby, data filtering and error correction methods are used to achieve continuous time series. The methods were developed at three different measuring gauges, whose cameras record single images and videos every 15 minutes over several months. The accuracy of the water level measurement is in the centimetre range, even at night with the support of infrared emitters. Depending on the water level, there are deviations in the flow rate, which average less than 10%.
Are there thick sediments within South Pole Basin? Investigating the lithology of SPB using COLDEX airborne geophysics 
Authors: Kerr Megan , Young Duncan , Shen Weisen , Ng Gregory , Singh Shivangini , Buhl Dillon , Greenbaum Jamin , Yan Shuai , Blankenship Donald
Published: March 2024

Because sedimentary basins may exert considerable control over ice sheet dynamics and basal heat flow, it is vital to constrain the extent, thickness, and level of consolidation of sediments throughout the continent and at local scales. Until recently, the South Pole Basin (SPB), situated between the Gamburtsev Subglacial Mountains, the Transantarctic Mountains, and Recovery Subglacial Highlands, has been one of Antarctica's least-explored regions. Previous studies based on seismic and machine learning models, including those by Baranov & Morelli (2023) and Li et al. (2022), have characterized SPB as a sedimentary basin with sediment thicknesses exceeding 1 km. Conversely, a seismic study conducted by Zhou et al. (2022) identifies SPB as a region with little to no sedimentary rock. A lack of dense geophysical data as well as the inherent difficulty of studying geology beneath the Antarctic Ice Sheet introduced a large amount of uncertainty into these assessments. Recent airborne radar, gravity, and magnetics data collected by the Center for Oldest Ice Exploration (COLDEX) has revealed two distinct geomorphological provinces within South Pole Basin: the southern portion of SPB which exhibits relatively smooth, reflective bedrock, while the northern SBP manifests as much rougher terrain. The abrupt boundary between Inner and Outer SPB is associated with the onset of subglacial melting, inferred from a rapid thinning of the basal layer, decreased ice sheet surface slope, and presence of subglacial lake-like features. In addition to surficial differences, these provinces are marked by distinct free-air, Bouguer, and isostatic gravity signatures. A large, arc-shaped magnetic high parallel to Recovery Subglacial Highlands cuts across SBP, facilitating a robust depth to basement analysis and providing constraints for gravity inversions. By integrating COLDEX data with previous airborne surveys and newly collected seismic data, we offer a revised geological interpretation of the South Pole Basin and discuss its tectonic history, potential for groundwater storage, and the preservation of ancient ice in this region.
Constraints on long-term seismic hazard from an intact, vulnerable stalagmite for the surroundings of Ördöglik (Čertova diera) part of Domica cave, Slovakia
Authors: Gribovszki Katalin , Mónus Péter , Shen Chuan-Chou , Pinti Daniele , Ghaleb Bassam , Prácser Ernő , Lednická Marketa , Czirok Lili , Jerg Zoltan , Novák Attila , Bazsó Tamás , Brolly Gábor , Szalai Sándor
Published: March 2024

To verify seismic hazard maps by independent observations that serves long-term information should be necessary. It requires studying vulnerable dripstones, since they survived all earthquakes that have occurred over thousands of years, depending on the age of them. Examination of an intact vulnerable stalagmite (IVSTM) in Ördöglik part of Domica cave (Slovakia) has been done. This IVSTM is suitable for estimating the upper limit of horizontal ground acceleration (HGA) generated by prehistoric earthquakes. This research is the continuation of our previous examination of IVSTMs in Baradla and Domica cave system, north-east Hungary.               The density, the Young’s modulus and the tensile failure stress of the samples originating from broken speleothems have been measured in geo-mechanical laboratories, whereas the dimensions and natural frequency of the IVSTM was determined by different types of in situ observations. The value of HGA resulting in failure and the natural frequency of the IVSTM were assessed by theoretical calculations. The ages of the samples taken from a column next to the investigated IVSTM at different heights have been determined by MC-ICPMS analysis. The measured ages fall between about 7.6 and 2.4 kyr. The critical HGAvalues as a function of time going back into the past determined from the stalagmite that we investigated are presented. Our results show that all values of probabilistic seismic hazard maps, SHARE Map (Giardini et al. 2014) and PSHA Map (Tóth et al. 2006) at the location of Ördöglik part of Domica cave, are above the critical horizontal ground acceleration (CHGA) curve calculated by using the dimensions, geo-mechanical and elastic parameters of IVSTM, and the values of CHGA caves are lower than 0.05g since 2.7 kyr (0.05g was estimated by Szeidovitz et al. (2008) using another vulnerable stalagmite 4 km far from Ördöglik, in the Baradla cave.) All these means that the seismic hazard is overestimated at the territory of Ördöglik, Domica cave.               This result have to be taken into account when calculating the seismic potential of faults near to Ördöglik part of Domica cave (e.g. Darnó and Rozsnyó lines).
Storyline simulations suggest a northward expansion of European droughts in warmer climates.
Authors: Sánchez Benítez Antonio , Ionita Monica , Athanase Marylou , Jung Thomas , Ma Qiyun , Goessling Helge
Published: March 2024

Climate change is causing an increase in the frequency, intensity and persistence of heatwaves and droughts, as seen, for example, in Central Europe in recent years. These changes are expected to be even more severe in the future. Two factors contribute to these changes in extreme events: dynamic changes – changes in the likelihood of weather patterns  – and thermodynamic changes. While the former are uncertain in future climate projections, the latter are characterized by a high signal-to-noise ratio, as there is a robust and ubiquitous rise in land-surface temperatures.To better understand and analyze both contributions, we employ the so-called "event-based storyline approach", which involves nudging our global CMIP6 coupled climate model (AWI-CM1) towards the observed large-scale free-troposphere winds using various climate background conditions and initial states. This enables us to simulate the same weather conditions, including jet streams and blockings, in different climates: preindustrial, present, and in 2 °C, 3 °C, and 4 ºC warmer worlds. This methodology provides an efficient way of making the consequences of climate change more understandable to experts and non-experts, as extreme events that are fresh in people's memory are simulated in different climates with moderate computational resources.Our simulations successfully reproduce recent hot and dry extreme events, like the 2019 or 2022 European heatwaves and the record-breaking 2022 drought. Our experiments reveal an intensification of these extremes from preindustrial to present climates (attribution), mainly in southern Europe, with no major changes in Central and Northern Europe. However, we project that this exacerbation will expand northward in future warmer climates, leading to even more severe drought in Central Europe and the Mediterranean by the end of the century. Taking advantage of our methodology we explore the physical mechanisms helping to exacerbate these events in future warmer climates.
Interactions of internal gravity waves with other waves and mesoscale eddies
Authors: Sebastia Saez Pablo , Eden Carsten , Chouksey Manita
Published: March 2024

We find internal gravity waves everywhere in the oceans. The interaction of these waves with other waves or eddies are key to the energy transfers in the ocean and can also lead to wave breaking and density mixing, which in turn drives the large-scale mean flow. The importance of wave-wave interactions compared to wave-mean flow interactions, however, remains largely unknown. We present two methods to better understand both processes: First, the scattering of waves by other waves is evaluated numerically using the kinetic equation derived from the assumption of weak interactions. Second, the interaction of waves with a local coherent meso-scale eddy and a random eddy field is simulated using a novel numerical model called the Internal Wave Energy Model based on the six-dimensional radiative transfer equation. We find mainly a forward energy cascade due to wave-wave interactions. Waves loose energy to the local eddy at its rim in a critical layer like behaviour, while the eddy field scatters the waves along a constant frequency cone.
Investigating Lunar Ionosphere Using GRAIL Radio Science Signals
Authors: Yang Yu-Ming , Oudrhiri Kamal , Withers Paul , Erwin Daniel A. , Buccino Dustin R. , Haha Inseob
Published: March 2024

The nature of the dense lunar ionosphere is controversial; the maximum electron density values in observed vertical profiles obtained from previous Lunar missions vary by two orders of magnitude. NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission consisted of an identical pair of spacecraft approximately 100 km apart in a circular polar orbit around the Moon at a mean altitude of 55 km during the science phase in 2012. The two GRAIL spacecraft conducted various radio science observations to determine the lunar gravity field. As a serendipitous consequence of these primary observations, the one-way spacecraft - Earth radio occultation observations of the lunar ionosphere were acquired using a carrier-only X-band radio signal from the Radio Science Beacon referenced to an onboard ultrastable oscillator (USO). GRAIL’s X-band Radio Science beacon (RSB) data provide applicability for the radio occultation of the lunar electron density profiles with the uncertainty of frequency residual measurement ~ 1 mHz corresponding to ~  2x108 m-3 electron density uncertainties. We will present our analysis of the electron density profiles retrieved from GRAIL Radio Science Beacon data to understand the formation and variations of the moon ionosphere. The findings of GRAIL results will improve our understanding of how those variations are spatial (e.g., latitude, longitude, solar zenith angle) or temporal (e.g., responses to external factors, such as meteor impacts and solar winds) during the GRAIL mission period.
Preliminary CSR GRACE RL07 re-processing results 
Authors: Zhang Chaoyang , Tapley Byron , Save Himanshu , Nagel Peter , Kang Zhigui , Poole Steven , Tamisiea Mark , Wang Furun
Published: March 2024

The fifteen and half years long GRACE temporal gravity data has greatly contributed to interdisciplinary studies especially in climate and solid Earth sciences. To further improve the noise level and error characteristic of the GRACE temporal gravity solutions, as well as provide an archival record for supporting a multidecade mass change measurement based on measurement continuity between the GRACE and GRACE Follow-On mission, the GRACE RL07 re-processing has been carried out at CSR. We will use an initial version of the GRACE Level1B  data (i.e. version 04P), updated background models, new GPS observation strategy and improved observation noise model for the RL07 re-processing. In this poster, we will present preliminary results from the GRACE RL07 re-processing and compare them with the GRACE RL06 solutions using different metrics.       
Discovering equations that govern wave breaking evolution using scientific machine learning
Authors: Tang Tianning , Chen Yuntian , Taylor Paul , Adcock Thomas
Published: March 2024

Artificial intelligence and machine learning are known to be excellent at empirical modelling of complex systems. These empirical models, however, usually can only provide limited physical explanations about the underlying systems. With a “knowledge discovery” scheme in machine learning, instead of being constrained by fitting the coefficients, can we now discover an equation that can shed light on the underlying physics? In this presentation, we will focus on a real fluid mechanics challenge as an example to demonstrate the potential of such a scheme – modelling wave breaking evolution.In this ongoing study, we use symbolic regression to discover the equation that describes the wave breaking evolution from a large dataset of Direct Numerical Simulations of breaking waves. We found a new boundary equation that approximates the surface elevation (water-air interface) to evolve forward in time even during the breaking-in-progress stage, whereas traditional potential flow type equations will eventually become unstable when the overturning jet touches the crest. Unlike empirical models where the underlying dynamics are hidden in coefficients/matrixes, the physical meaning of each term of the discovered equation can be revealed successfully through math derivation and simulation. The new boundary equation suggests a new characteristic of breaking waves in deep water – a decoupling between the water-air interface and the fluid velocities. The current model is only limited to unidirectional spilling breaking waves in deep water but can be easily extended to accommodate more complex breaking behaviour.
Comparison of plant fossil assemblages across the Permian–Triassic Boundary with simulated biomes in alternative climatic states
Authors: Brunetti Maura , Ragon Charline , Vérard Christian , Kasparian Jérôme , Nowak Hendrik , Kustatscher Evelyn
Published: March 2024

Terrestrial floras underwent major changes across the Permian–Triassic Boundary (PTB), as observed in the distribution of plant fossil assemblages before (Wuchiapingian, Changhsingian) and after (Induan, Olenekian, Anisian) the PTB [1]. While marine animals suffered the most severe mass extinction event at the Permian–Triassic transition, terrestrial plants were marked by extreme shifts in their distribution and composition which can arise when abiotic drivers reach a critical threshold or tipping point [2]. Interestingly, using a coupled atmosphere-ocean-sea ice-land configuration of the MIT general circulation model, three alternative climatic states have been found for the Permian–Triassic paleogeography [3], namely a cold state with perennial ice in the northern hemisphere reaching 40°N and global mean surface air temperature (SAT) of 16–18 °C, a hot state without ice and SAT larger than 30 °C, and an intermediate warm state. These states turn out to be stable over a common range of atmospheric CO2 content, thus allowing for hysteresis paths and tipping points in abiotic drivers, such as the global surface air temperature. Through asynchronous coupling with the vegetation model BIOME4, the distribution of the biomes corresponding to each climatic state has been obtained.Here, we perform a detailed comparison between the biomes corresponding to the alternative climatic states and the distribution of plant fossil assemblages from the Wuchiapingian to the Anisian. For each observed assemblage, the geodetic distance to the closest simulation grid point with the same biome is calculated. This allows us to quantify, through statistical significance tests, the resemblance between the simulated biomes and the observed distribution of plant fossil assemblages, and thus to determine the climatic state which minimizes the mean distance at each geological period. We find a clear signature of climatic shifts from a cold state in the Changhsingian to a hot state in the Olenekian, whereas during the earliest Triassic (Induan) the attribution to a particular climatic state is not univocal, strong climatic oscillations being still present in the aftermath of the PTB.   References[1] H. Nowak, C. Vérard, E. Kustatscher, Frontiers in Earth Science 8, 613350 (2020)[2] E. Schneebeli-Hermann, Frontiers in Earth Science 8, 588696 (2020)[3] C. Ragon, C. Vérard, J. Kasparian, M. Brunetti, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-1808, 2023 