bluuebunny/crossref_metadata_2025 huggingface dataset:
New neutral density estimates and forecasts in the framework of project ESPRIT
Authors: Strasser Andreas , Krauss Sandro , Scherf Manuel , Suesser-Rechberger Barbara , Lammer Helmut
Published: March 2024

In the ongoing project ESPRIT, a goal is to investigate the contribution of the chemical composition and associated chemical reactions to the Earth’s upper atmosphere. This is realized through a combined analysis of thermospheric neutral density estimates and the exploration of external parameters of the interplanetary space, including variations in the magnetic field and the merged electric field. Regarding changes in the chemical composition of the Earth’s atmosphere, which might cause heating and cooling effects, we investigated TIMED/SABER measurements in conjunction with findings from the 1D first-principles hydrodynamic upper atmosphere model Kompot code, which shows some significant expansion in the density profile mainly based on the increased XUV flux from the Sun. The neutral mass densities were processed based on accelerometer measurements as well as on kinematic orbit information (Süsser-Rechberger et al. 2022). This allowed us to successfully process kinematic orbits for 19 different satellites at an altitude range of approximately 400 to 1300 km. Both approaches are realized using the in-house software package GROOPS. During the evaluation, significant improvements in the processing and parametrization could be achieved compared to previous solutions, especially through refined models for solar radiation pressure, the Earth’s re-radiation, the thermal radiation of the satellite itself and the consideration of the chemical composition of the atmosphere. Based on these new neutral density estimates, investigations regarding the effects of solar eruptions on the various satellites are performed and used for attempting to forecast the orbital decay of LEO satellites.
Asperity distribution and earthquake recurrence time based on patterns of forerunning earthquakes.
Authors: Kambala Venkata Gangadhara Rao , Senatorski Piotr
Published: March 2024

Abstract. Due to the long recurrence time of the largest earthquakes and the short time covered by seismic catalogues, the potential for the strongest earthquakes in a given region should be estimated based both on combined seismological and geodetic observations, as well as on the developed seismicity models. At the same time, the asperity model, which is a general view of earthquake occurrence in seismic zones, still requires refinement and more solid empirical support.In this study, we use new data science methods to analyze and interpret various data from selected subduction and collision zones, including Japan, Chile, and Himalaya-Nepal regions. First, we estimate the expected recurrence times of large earthquakes within a given magnitude range as functions of the Gutenberg-Richter’s b values, for  the assumed maximum magnitude and seismic moment deficit accumulation rate due to the tectonic plate movement. Second, we show seismicity patterns and underlying asperity structures using graphs representing the forerunning and afterrunning earthquakes, which are strictly defined based on the location of earthquakes in time and space, as well as their sizes.In particular, we propose a method to estimate the rupture areas and magnitudes of possible megathrust earthquakes based on seismicity from the last few decades. We use the graph characteristics to distinguish among different seismicity patterns and scenarios. We also argue that changes in these features over time and space can be used to forecast seismicity forecasting. Keywords: Earthquake forecasting, Gutenberg-Richter law, Recurrence time, Asperities, Forerunning earthquakes.
Catchments deviate less from their own Budyko curves over time than previously thought
Authors: Ibrahim Muhammad , Coenders Miriam , Hrachowitz Markus , van der Ent Ruud
Published: March 2024

Quantification of precipitation partitioning into evaporation and runoff is crucial for predicting future water availability. Over longer time scales, the widely used Budyko Framework, which is a curvilinear relationship between evaporative index (i.e., actual evaporation over precipitation) and aridity index (i.e., potential evaporation over precipitation), robustly quantifies precipitation partitioning under prevailing climatic conditions. Global long-term records indicate that catchments generally follow Budyko curves; however, a narrow scatter around these curves have been demonstrated in various studies, raising questions about the framework's applicability. To address this, we quantified (based on historical long-term water balance data of over 2000 river catchments world-wide) the global, regional and local distributions of deviations from parametric Budyko curves, between multiple 20-year periods over the last century. This process resulted in four 20-year distributions of deviation for each catchment. On average, it was observed that in 73% of the catchments, the long-term median deviation values across these distributions were not significantly different from zero suggesting minimal to no median deviations. Furthermore, it is found that for majority of the catchments (78%) the four 20-year distributions of deviations are not significantly different to each other implying consistency in deviations among different 20-year periods. Our analysis revealed that, for 80% of these catchments, the long-term median deviations, for the last century, fall within the range of ±0.02 with a very narrow spread in Interquartile Range values. These findings demonstrate that while catchments do not precisely follow the expected Budyko trajectories, the deviations are small and quantifiable. Consequently, by taking into account these deviations, the Budyko Framework remains a valuable tool for predicting future evaporation and runoff under changing climatic conditions, within quantifiable margins of error.
Intercomparison and Definition of Uncertainties of Deep-Time Global Earth Reconstructions: What’s the problem?
Authors: Vérard Christian , Franziskakis Florian , Giuliani Grégory
Published: March 2024

Global Earth reconstruction maps are used as baseline information for many studies, with high-level impacts and large implications. Yet, virtually no study fundamentally question the reliability of those reconstructions. In many cases, the model the study uses is not even credited. The reason for the absence of such discussion probably lies in the fact that none of the plate tectonic / palæogeographic modellers themselves have been able so far to assess the reliability of their own maps.Why? First, because actually, there are ‘palæo-continental’, ‘plate tectonics’, ‘palæo-environmental’, and ‘palæogeographic’-types of reconstruction and it is difficult to compare apples and oranges. Second, because the workflow, definition, standard and vocabulary used to by the modellers can be quite different. And third and overall, because data, which reconstructions are based upon, may be contradictory and modellers must make choices.If, for example, 4 data suggest a collision at a given time and a fifth does not, can we state that the model should display a collision zone at the 80% confidence level? What geological information is undoubtedly a proof of a collision? If among the 5 data, 2 corresponds to flysch-series, 1 corresponds to S-type granite, the 4th to tectonic unconformities and structural deformation, and the 5th is the definition of a retrograde path of metamorphic P – T conditions, is it sufficient to talk about collision, and do the 5 data have the same weight in terms of uncertainties? What about if the model does not display the collision zone at time the 4 first data suggest collision, but does display collision at the next time slice in agreement with the 5th information?Contradictory data and debatable choices will always exist, and the existence of numerous global Earth reconstruction models is thus a wealth. However, in order to talk about uncertainties and to allow some intercomparison, the modellers of the Earth reconstruction community must collaborate, form an International Panel for Earth Reconstruction (IPER), and lay the foundation for shared definitions, concepts, vocabulary, and FAIR principles. A quantification of uncertainty on past reconstructions may then possibly be achieved by intercomparison between various models.
Application of a low-cost ultraviolet camera solution for permanent sulphur dioxide measurements at six volcanoes worldwide.
Authors: Pering Tom , Wilkes Thomas , Nadeau Patricia , Hidalgo Silvana , Aguilera Felipe , Layana Susana , Aisyah Nurnaning , Humaida Hanik , Sakti Alfabi , Kern Christoph
Published: March 2024

Ultraviolet (UV) cameras provide advantages in spatial and temporal resolution for the measurement of sulphur dioxide (SO2) emission rates, when compared to the more common differential optical absorption spectroscopy (DOAS) instruments. Up to this point, however, most instances of UV camera usage are restricted to discrete campaigns, rather than permanent installations. Notable exceptions include Stromboli, Etna, and Kīlauea (2013-2018). The reasons for this are largely related to cost, with commercially available UV cameras often being prohibitively expensive, and also to the challenges associated with developing robust algorithms for automated retrieval of emission rates from the collected imagery. The PiCam, developed at the University of Sheffield, is a new UV camera system designed for permanent installation in the field and provides automatic measurements of SO2 emission rates (for full details see Wilkes et al., 2023, doi: 10.3389/feart.2023.1088992). The PiCam is currently installed at six volcanoes globally: Kīlauea (USA), Cotopaxi and Reventador (Ecuador), Lascar and Lastarria (Chile), and Merapi (Indonesia). Each location has unique requirements and setup, for instance the UV cameras at Reventador and Lastarria operate autonomously but require user visits for data download. Those at Kīlauea and Merapi are integrated within existing telemetry solutions, while at Lascar and Cotopaxi we have begun to integrate Starlink satellite data telemetry alongside our cameras. We present some early results from measurements at Kīlauea where emission rates are compared to more traditional measurements using DOAS. Since the PiCam installation in 2022, the system has recorded multiple styles of activity, from low-level degassing during periods of quiescence to syn-eruptive emissions exceeding 10,000 t/d. Our work highlights continuing challenges of processing of UV camera data, where automated protocols and real-time processing for reliable emission rate retrievals are still in their infancy.
The greenhouse gas budget of terrestrial ecosystems in China since 2
Authors: Gao Yuanyi , Wang Xuhui , Wang Kai , Sang Yuxing , Wang Yilong , Zhang Yuzhong , Hong Songbai , Zhang Yao , Yuan Wenping , Piao Shilong
Published: March 2024

As one of the world’s economic engine and the largest greenhouse gases (GHGs) emitter of fossil fuel in the past two decades, China has expressed the recent ambition to reduce GHG emissions by mid-century. The status of GHG balance over terrestrial ecosystems in China, however, remains elusive. Here, we present a synthesis of the three most important long-lived greenhouse gases (CO2, CH4 and N2O) budgets over China during the 2000s and 2010s, following a dual constraint bottom-up and top-down approach. We estimate that China’s terrestrial ecosystems act as a small GHG sink (-29.0 ± 207.5 Tg CO2-eq yr-1 with the bottom-up estimate and -75.3 ± 496.8 Tg CO2-eq yr-1 with the top-down estimate). This net GHG sink includes an appreciable land CO2 sink, which is being largely offset by CH4 and N2O emissions, predominantly coming from the agricultural sector. Emerging data sources and modelling capacities have helped achieve agreement between the top-down and bottom-up approaches to within 25% for all three GHGs, but sizeable uncertainties remain. 
SHARP project – an integrated approach for assessing CO2 storage containment risks
Authors: Larsen Tine B. , Skurtveit Elin , Pearson Steve , Kettlety Tom , Choi Jung Chan , Huang Chen , Carlton Brian , Kendall J. Michael , Kupoluyi Michael , Kühn Daniela , Roberts Daniel , Hindriks Kees K. , Furre Anne-Kari , Barnhoorn Auke , Singh Devendra N. ,   SHARP Team
Published: March 2024

SHARP is an interdisciplinary project with the overall aim to develop improved methods for quantitative assessment of subsurface CO2 storage containment risks. The project combines subsurface stress models, rock mechanical failure experiments, and seismicity observations with probabilistic modelling of fault stability, seismic hazard, and containment risk. This presentation will summarise and give a status update on risk quantification work of the SHARP project. Uncertainties and parameter ranges are included for the failure data, and independent and dependent failures of geological barriers are treated probabilistically. A new catalogue of natural seismicity in the North Sea form the basis for constructing offshore ground motion prediction equations (GMPEs) and an updated regional probabilistic seismic hazard analysis (PSHA). Natural seismicity, pressure, and pressure induced seismicity are identified as potential root causes of leakage (triggers) and a catalogue of generic release diagrams are built for realistic geological settings. The generic release diagrams are mapped onto test cases from the North Sea. The geological containment risk with uncertainties will be evaluated though event tree analysis and Monte Carlo runs, where the inputs are the quantified contributions from release diagrams, probabilistic fault stability analysis and the seismic hazard curve.
Investigating the Chemical Composition of Organic Aerosols and their Contribution to the Oxidative Potential
Authors: Breuninger Anna , Vogel Alexander , Steimer Sarah
Published: March 2024

Atmospheric aerosols play an important role not only due to the effect on climate but especially because of the adverse effects on human health, which studies consistently link to the exposure to particulate matter. Here, especially fine particles below a diameter of 2.5 μm can enter deep into the lungs, causing inflammation or translocate into the bloodstream and eventually lead to further disease.To investigate and describe the potential toxicity of atmospheric particles, the oxidative potential (OP) can be measured. Since particles can be formed by many reaction paths and therefore be a mixture of many compounds, a deeper understanding of the composition is needed in order to understand the main chemical drivers for OP. It is known, that especially metals and secondary organic aerosols (SOA) lead to OP, but in order to attribute sources, afurther chemical characterization of SOA, linked to OP, is needed.In this study, 42 samples from different locations in Frankfurt, Germany and Beijing, China have been measured by inductively coupled plasma - mass spectrometry (ICP-MS), in order to obtain the metal content and by high pressure liquid chromatography - high resolution mass spectrometry (HPLC-HRMS) to determine organic compounds and their composition groups via non target analysis. The OP then was determined by extracting the filters and either measuring directly or treating with Chelex® 100 to remove the metals and carry out the measurement afterward. By employing this technique, the contribution of metals and organics can be investigated separately to gain a better understanding of the OP caused by SOA. In order to examine the contribution of different compound groups to OP, a hierarchical cluster analysis and several Pearson correlations have been carried out. By this approach, similarities between samples can be observed, which then might give an indication about relevant compounds. Moreover, correlations between the variability of the OP throughout the sample and the variability of compounds point to certain OP-effective compounds.First results show that the metal containing extracts have a higher volume-normalized OP (OPV ) compared to the non-metal ones, with 0.2 to 5 nmol DTT min-1m-3, which is mainly due to manganese and copper. After the Chelex® 100 treatment, there is still a OPV of 0.1 up to 4 nmol DTT min-1m-3, indicating the significance of organic matter, causing the oxidative potential. Comparing the different locations, the samples from Beijing show an OP up to fourtimes higher than samples from Frankfurt. Looking deeper into the chemical composition, especially chemical groups containing phosphor and nitrogen, such as CHOP and CHNO, correlate with high OP.
Socio-Economic Vulnerability assessment and validation in Seoul, South Korea 
Authors: Vuong Tai Chi , Kim Dongkyun , Kim Soohyun , Kim Yongchan , Choi Hyojeong , Lee Jeonghun
Published: March 2024

Vulnerability is regarded as a crucial element in disaster risk reduction, garnering increasing attention from researchers. However, these assessments typically conclude with the spatial representation and analysis of vulnerability index values, with very few attempts made on vulnerability validation. This study has employed Principal Component Analysis (PCA) algorithm for the entire 38 selected socio-economic features, resulting in 9 principal components (or factors) to estimate Socio-Economic Vulnerability Index (SEVI). The results reveal consistent vulnerability levels in over half of the dongs (administrative units), compared with SEVI estimated from a subjective weighting scheme based on expert experience. Meanwhile, the remaining dongs exhibit a change in only one level of vulnerability. SEVI values and ranks from PCA were subsequently internally validated through global uncertainty and sensitivity analyses using Monte Carlo method. The vulnerability scores of all input features were randomly generated based on their fitted probability distribution functions, serving as input parameters for 39,936 Monte Carlo simulations. The median statistic was employed to evaluate the vulnerability uncertainty based on both bias of estimated SEVI values and ranks in comparison with simulated data. The findings from this analysis revealed that medium-low and medium vulnerability levels tend to be underestimated, while medium-high and high levels primarily witness an overestimation tendency. The bias in SEVI ranks was further employed to assess the vulnerability uncertainty. In the sensitivity test, a tornado diagram was created to illustrate the explanation of each feature to the overall SEVI variability. The results indicate that the feature with highest explanation of SEVI variability is the number of families with only children and a mother, accounting for more than 5%. The methodology employed in this study is applicable to areas with limited social and economic data sources. Based on our findings, we suggest that the areas with low bias on SEVI values or ranks are reliable for developing disaster risk mitigation strategies, while other areas require further consideration. Additionally, the results from the sensitivity test provide valuable support for future research when selecting input features for socio-economic vulnerability assessment.Acknowledgement:This study was supported by: (1) The National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2022R1A4A3032838) (50 % grant); (2) Korea Environment Industry & Technology Institute (KEITI) through R&D Program for Innovative Flood Protection Technologies against Climate Crisis Project, funded by Korea Ministry of Environment (MOE) (RS-2023-00218873) (50 % grant).
Performance of Through-Water Structure-from-Motion Photogrammetry in Gravel-Bed Rivers: An Experimental Investigation
Authors: Zhang Chendi , Li Wenqi , Hassan Marwan , Sun Ao'ran , Qin Chao
Published: March 2024

Structure-from-Motion (SfM) photogrammetry has become an efficient approach in acquiring high-resolution three-dimensional topographic data in geosciences and can be used for measuring submerged riverbed surfaces in shallow and clear water systems. However, the performance of through-water SfM photogrammetry has not been fully evaluated for gravel-bed surfaces, which limits its application to the morphodynamics of gravel-bed rivers in both field investigations and flume experiments. The measurement quality includes: (i) accuracy and precision of the measured underwater bed surface elevations; and (ii) statistical properties (first four moments and structural functions) of the bed surface elevation distributions.In order to evaluate the influence of bed texture, flow rate, ground control point (GCP) layout, and refraction correction (RC) on the measurement quality of through-water SfM photogrammetry, we conducted a series of experiments in a 70 m-long and 7 m-wide flume with a straight artificial channel under strictly controlled conditions. The channel size was comparable to a small natural stream so that the results could provide insights for not only flume experiments but also for UAV-based field investigations. Bed surfaces with strongly contrasting textures (fine sand cover vs. gravel cover) in two 4 m-long reaches were measured under five constant flows with three GCP layouts, including both dry and underwater GCPs. All the submerged surface models were compared with the corresponding dry bed surfaces to quantify their errors in elevations, moments, and outcomes of structural functions.The results illustrated that the poorly sorted gravel-bed led to smaller elevation errors than the bed covered by fine sand. The use of underwater GCPs made significant improvements to the elevation accuracy of direct through-water SfM photogrammetry, but counteracted with RC. The elevation errors of the submerged models linearly increased with water depth for all the tested conditions of bed textures, GCP layouts, and discharges in the uncorrected models, but the increasing slopes varied with bed texture. Fine sediment transport caused significant elevation errors, while the static sand dunes and grain clusters did not lead to noticeable errors in the corrected models with dry GCPs. The movement of fine sediment at high flows also led to significant errors in the second to fourth moments, horizontal correlation scales, Hurst exponents, and the errors in statistical properties for both uncorrected and corrected submerged models. The results show that through-water SfM photogrammetry is promising in capturing the topographic and statistical properties of underwater gravel-bed surfaces if fine sediment transport is carefully addressed.Keywords: Topographic measurement; Structure-from-Motion (SfM); through-water photogrammetry; gravel-bed river; refraction correction
Detecting lowland thermokarst development by UAV remote sensing in the Stordalen mire, Abisko, Sweden 
Authors: Thomas Maxime , Moenaert Thomas , du Bois d’Aische Éléonore , Villani Maëlle , Hirst Catherine , Lundin Erik , Jonard François , Lambot Sébastien , Van Oost Kristof , Vanacker Veerle , Giesler Reiner , Mörth Carl-Magnus , Opfergelt Sophie
Published: March 2024

In situ field studies in thawing permafrost regions have shown that C emissions resulting from organic carbon (OC) decomposition depend among others on the variability in soil water content, which can be directly related to microtopography. A more precise assessment of the evolution of permafrost C emissions as a function of thermokarst development requires high-resolution quantification of thermokarst-affected areas, as lowland thermokarst development induces fine-scale spatial variability (~ 50 – 100 cm). Here, we investigate a gradient of lowland thermokarst development at Stordalen mire, Abisko, Sweden, from well-drained undisturbed palsas to inundated fens, which have undergone ground subsidence. We produced orthomosaics and digital elevation models from very-high resolution (10 cm) UAV photogrammetry as well as a spatially continuous map of soil electrical conductivity (EC) based on Electromagnetic Induction (EMI) measurements performed in September 2021. In conjunction, we measured in situ the soil water content from the different stages of thermokarst development at the same period. The soil EC values are contrasted along the gradient in line with contrasts observed in the landscape classification derived from the orthomosaics and digital elevation models: palsas are flat areas with low soil EC (drier), whereas fens are subsided areas with higher EC (water-saturated). Areas in the course of degradation (transition zones) are well identified based on their higher slope, and broad range of EC. Importantly, these transition zones are only detected using a very fine spatial scale (i.e., 10 cm) coupled to information on the microtopography. Compared to a set of previously collected orthomosaics and digital elevation models, our results show an acceleration of thermokarst development in this area with a rate of palsa decline 4 to 10 times greater in 2019-2021 than in 2000-2014.
Analysis and research on interactions between human systems and the extreme rainstorm setting
Authors: Qi Shuwen
Published: March 2024

The losses caused by flood emerges from the intricate interplay between natural and human systems. Particularly noteworthy is the flood disaster induced by exceptionally intense precipitation within densely populated mega-citys. A poignant illustration of this dynamic unfolded on July 20th, 2021, in the city of Zhengzhou, China. This event precipitated 380 fatalities, accompanied by a direct economic loss  exceeding  5.6 billion U.S. dollars, thereby exerting profound repercussions on national economic and social development. To unravel the intricate interactions between human systems and the extreme natural setting, our investigation delves into specific disaster events, such as fatalities occurring in metro line 5 and the tunnel of Jing-guang urban expressway, the overtopping peril of Guojiazui reservoir, and the explosion at an aluminum alloy factory. Employing a systemic perspective, we analyze human activities during the phases of early warning, response and disposal. Our findings underscore pivotal factors contributing to the substantial loss of life, including inefficient organization and preparedness by local government entities, inadequate emergency response measures from various departments, and a lack of readiness among the local populace. In response to these identified shortcomings, we proffer concrete recommendations for disaster prevention. These suggestions serve as valuable references for mega-cities, advocating measures such as fortifying the linkage mechanism among governmental departments and enhancing public awareness regarding flood hazards.
Deformation and healing processes in the damage zone of a lower-crustal seismogenic fault
Authors: Michalchuk Stephen Paul , Gies Nils B , Lüder Mona , Ohl Markus , Dunkel Kristina , Hermann Jörg , Plümper Oliver , Menegon Luca
Published: March 2024

In anhydrous, strong, and metastable lower-crustal rocks, coseismic fracturing is an effective mechanism for creating pathways for fluids to infiltrate and interact with the host rock, ultimately resulting in metamorphism and rheological weakening. In this study, we have characterized the damage zone flanking a lower-crustal pseudotachylyte (solidified frictional melt produced during seismic slip) to understand the fracture generating and fluid-assisted healing processes operating during and immediately after a seismic event.The Nusfjord East shear zone (Lofoten, Norway) is a network of coeval pseudotachylytes and mylonitized pseudotachylytes that formed at lower-crustal conditions within anhydrous anorthosites. We present a micro- and nanostructural analysis focusing on plagioclase in the damage zone of a pseudotachylyte using focused ion beam (FIB) prepared scanning transmission electron microscopy (STEM), Fourier Transform Infrared (FTIR) Spectroscopy, electron backscatter diffraction (EBSD) analysis, electron microprobe analysis (EMPA), and SEM-cathodoluminescence (CL) imaging.The damage zone of the host anorthosite is characterized by a network of comminuted primary plagioclase (plagioclase1) grains with minimal offset. Very fine (
More than 60 years of measurements of Standard-Phase-Heights over Western Europe – Trends and long-term oscillations of the mesosphere
Authors: Peters Dieter H.W. , Mani Sivakandan
Published: March 2024

For more than 60 years, ﬁeld strength measurements of the broadcasting station, Allouis (Central France), have been received at Kühlungsborn (54° N, 12° E), Mecklenburg, Northern Germany. Beginning with the year 1959 these so-called indirect phase-height measurements of low frequency radio waves (with a frequency of about 162 kHz) are used to examine trends and the long-term oscillations over Western Europe. The advantages of this method are the low costs and the simplicity of operation. Results of the updated fifth release (R5, 1959-2019) of standard-phase heights (SPH) are presented.The statistical analysis of the SPH series shows a significant overall trend with a decrease of 116 m per decade indicating a subsidence of the long-radio wave reflection height of about 700 m during R5. As expected the daily time series of SPH shows in its spectrum dominant modes which are typical for the solar cycle, ENSO and for QBO bands, indicating solar and lower atmospheric influences. Solar cycle and ENSO (-QBO)-like band-pass show a growing increase of SPH up to 1987, followed by a decrease afterwards.For summer months during solar minimum years, without solar influences and without stratopause altitude trend, a thickness temperature trend of the mesosphere is significant with a trend value of -0.47 ± 0.43 K/ decade. The overall cooling of the intrinsic mesospheric temperature during 60 years of observation is in the order of 3 K. 
The Water System Explorer: understanding interactions between the natural and anthropogenic water system on a regional scale
Authors: van Huijgevoort Marjolein , Stofberg Sija , Raat Klaasjan , Bartholomeus Ruud
Published: March 2024

In the Netherlands the natural water system has been altered significantly to address human needs. Historically, the main water issues were related to water excess. However, recent dry years (2018-2020, 2022) have made it clear that drought affects many sectors as well. To deal with both extremes, a transition of the water system is needed with integral solutions.Exploring the effects of measures needed to improve the water system is challenging and needs to be done in an integrated way that considers the natural water system as well as the anthropogenic influence on that system. Often these effects are investigated using complex, spatially-distributed models that usually don’t include all interactions between water users and the water system, have long calculation times and require a certain computer capacity. To attain a first crude estimate of the effects, it is also possible to use a different approach like system dynamics models. System dynamics models provide less details and include less spatial variation, but can include more interactions between the different subsystems and have short calculation times.We have developed a system dynamics model, the Water System Explorer, that can be used to simulate the effect of human interventions on the water system. The Water System Explorer provides insight into the water system at a regional scale and can be used as a tool to support conversations between different stakeholders in a region. It is a strong simplification of reality, so it serves to give a first indication of potential measures and their effects, including trade-offs, in a specific region.The Water System Explorer includes the natural and anthropogenic system. For the natural system, four different landuse types are defined: agriculture, urban area, groundwater-dependent nature and groundwater-independent nature. The phreatic groundwater level is determined for each land use type, which interacts with the surface water and deep groundwater. The anthropogenic system includes the water demand of industry and households, drinking water supply and a wastewater treatment plant. Several interventions are included, for example, a ban on water abstractions for agriculture, introducing separated sewers, increasing surface water levels, applying managed aquifer recharge and re-use of effluent in agriculture, industry, or drinking water supply.The Water System Explorer has been applied for a region in the Netherlands. The tool reproduced general characteristics of the water system and illustrated the side-effects of water system interventions as a result of feedback mechanisms. The tool shows much potential for gaining insight into a regional water system to discuss measures with all stakeholders and for education purposes. 
The making of a Volcanic Ash DataBase (VolcAshDB) and its exploitation with machine learning
Authors: Benet Damià , Costa Fidel , Widiwijayanti Christina , Pallister John , Pedreros Gabriela , Allard Patrick , Humaida Hanik , Aoki Yosuke , Maeno Fukashi
Published: March 2024

The study of volcanic ash and its different components provides key information that can help understand the likely evolution of volcanic activity during early stages of a crisis and possible transitions towards different eruptive styles. However, classifying ash particles into components such as juvenile or lithic is not straightforward. Diagnostic observations may vary depending on the style of eruption, and there is no standardized methodology, which may lead to ambiguities in assigning a given particle to a given class. To address this problem, we created the web-based Volcanic Ash DataBase (VolcAshDB) which is made of > 6,300 multi-focused binocular images of particles from a range of magma compositions and types of volcanic activity (https://volcash.wovodat.org/). For each particle image, we quantitatively extracted 33 features of shape, texture, and color, and visually classified each particle into one of the four main components: free crystal, altered material, lithic, and juvenile. We used the data in VolcAshDB to setup a variety of machine learning-based models aimed at improving ash particle classification. We identified the features that are discriminant of a given particle type through explanatory AI and the Shapley values from the predictions made by an XGBoost model. We have also developed an accurate Vision Transformer model (93% accuracy) that could be potentially used by volcano observatories to obtain a relatively rapid and objective score on a particle-by-particle basis. Such models could be used for petrologic monitoring in a reproducible and systematic manner aiding in making more informed decisions for hazard mitigation.
Polar motion of a 3D viscoelastic earth model: Consequences for GIA signals in GRACE-FO
Authors: Klemann Volker , Bagge Meike , Dill Robert , Hagedoorn Jan M. , Martinec Zdeněk , Dobslaw Henryk
Published: March 2024

Surface deformations due to changes in the rotation of the Earth are significantly impacted by glacial isostatic adjustment (GIA). The long-term trend of polar motion contributes to global observations like that of the current satellite gravity mission GRACE-FO. The theory and how to apply this contribution to correct GRACE observational data is well understood and goes back to the concise studies of Mitrovica et al. (2005) and Wahr et al. (2015), respectively. According to the International Earth Rotation Service (IERS), a standard correction method is suggested, where the observed long-term trend of the polar motion is considered to originate from GIA. Recent studies show that the modelled GIA contribution to polar motion strongly depends on structural features of the Earth's interior as well as on the glacial history. Other processes like mantle convection or more recent climatic processes are attributed to contribute as well (Adhikari et al. 2018).In this presentation we focus on the impact of the Earth's viscosity structure on the modelled polar motion. In addition to its radial stratification, we discuss the influence of lateral variability. We apply the numerical 3D viscoelastic lithosphere and mantle model VILMA, which solves the gravitationally self-consistent field equations in a spherical geometry, and which considers the rotational feedback and the sea-level equation. The theory of Martinec and Hagedoorn (2014) applied here is not based on the normal mode theory, but solves the field equations in the time domain. We show the consistency of the chosen approach and rate the influence of lateral changes in viscosity against the impact of radial viscosity stratification. The study was motivated by the ESA Third Party Mission 'GRACE-FO' and contributes to the German Climate Modelling Initiative 'PalMod'.Lit:Adhikari, S, Caron L, Steinberger, B, ..., Ivins, ER (2018). What drives 20th century polar motion? Earth Planet. Sci. Lett. doi:10.1016/j.epsl.2018.08.059Martinec, Z, Hagedoorn, JM (2014). The rotational feedback on linear-momentum balance in glacial isostatic adjustment. Geophys. J. Int. doi:10.1093/gji/ggu369Mitrovica, JX, Wahr, J, Matsuyama, I, Paulson, A (2005). The rotational stability of an ice-age earth. Geophys. J. Int. doi:10.1111/j.1365-246X.2005.02609.xWahr, J, Nerem, RS, Bettadpur, SV (2015). The pole tide and its effect on GRACE time-variable gravity measurements: Implications for estimates of surface mass variations. J. Geophys. Res. Solid Earth. doi:10.1002/2015JB01198
Causes of Global Elastic Vertical Land Movement from 1900 to 2022
Authors: Knudsen Per , Ludwigsen Carsten Bjerre , Andersen Ole Baltazar , King Matt , Watson Christopher
Published: March 2024

Elastic vertical land movement (eVLM) is the lithosphere's immediate elastic response to the loading and unloading of the Earth's surface mass. Understanding eVLM is crucial for interpreting relative sea level changes, particularly in coastal regions where subsidence or uplift can significantly alter the impacts of sea level changes recorded by tide gauges. Here we present a comprehensive global eVLM model, offering valuable insights for geodesy and related fields, especially in assessing observations from tide gauges and GNSS. Our eVLM model spans from 1900 to 2022, featuring a 0.5-degree spatial resolution. It provides annual data from 1900 to 1990 and monthly data from 1991 to 2022, enabling both long-term and seasonal assessment. The dataset is available in three different reference frames: Centre of Mass (CM), Centre of Figure (CF), and ITRF2020, and thus suitable for many geodetic applications. This study incorporates mass change estimations from Greenland, Antarctica, global glaciers, and land water storage (LWS), divided into natural LWS variations and anthropogenic water management like groundwater depletion and dam retention. Thus, we can explain regional VLM patterns that cannot be solely attributed to Glacial Isostatic Adjustment (GIA) models, for example, subsidence across Australia or uplift in Scandinavia that is larger than modeled GIA.Methodology: We employed a composite loading model, integrating ice models from Greenland (Mankoff et al., 2021) and Antarctica (Otosaka et al, 2022; Nilsson et al, 2022) and glacier models (Hugonnet et al., 2022), GRACE observations, and a land water storage model (Müller-Schmied et al, 2023). Each of the aforementioned five causes of eVLM was perturbed with its uncertainty a thousand times, and the sea level equation was resolved for each variant using the ISSM-SEESAW framework (Adhikari et al., 2016). To align the results with observations in the ITRF2020 reference frame, which mirrors CM on secular timescales and CF on non-secular timescales (Dong et al, 2003). To accommodate this, we applied CM and CF Love loading numbers (Blewitt, 2003) in our calculations, enabling analysis in all three reference frames.
Statistical studies of the energy-altitude relation in the footpoints of solar flares observed by STIX
Authors: Mikula Katarzyna , Mrozek Tomasz
Published: March 2024

Solar flares are efficient accelerators of energetic particles, mainly electrons, which transport energy from reconnection site to the chromosphere. Energetic electrons are thermalized in the chromosphere and produce hard X-ray emission (HXR) following the thick-target bremsstrahlung mechanism. The thick-target model predicts that altitude of the HXR sources in the footpoints of solar flare decreases with increasing energy. The relation was registered for the solar flares observed with Yohkoh/HXT and RHESSI. In our research, we investigated the energy-altitude relation in flare footpoints in a group of strong (M and X GOES class) events that showed emission up to 84 keV recorded by the Spectrometer/Telescope for Imaging X-rays (STIX) onboard the Solar Orbiter. Here we present the results of analysis of the relation, e.g. temporal evolution and density distributions on selected examples. One of the interesting effects visible in some cases is bump in higher energies, when the sources appeared roughly on higher altitudes, which was very rare observed by previous X-ray instruments, but in STIX observations it’s very common. Thanks to unprecedented high temporal and spatial resolutions of STIX data, we can trace changes of plasma dynamics in footpoints like never before. 
Revisiting vegetation carbon and water flux representation during drought events in the ORCHIDEE land surface model
Authors: Abadie Camille , Maignan Fabienne , Peylin Philippe , Vuichard Nicolas , Raoult Nina , Bastrikov Vladislav
Published: March 2024

Climate change is projected to increase the frequency and intensity of droughts, inducing further water stress on vegetation. These water stress conditions impact both vegetation carbon and water exchanges that are regulated through stomatal diffusion. Land surface models (LSMs) have been developed to simulate the amount of carbon taken up by vegetation through photosynthesis (GPP), and the emission of water into the atmosphere through plant transpiration. However, LSMs struggle to accurately simulate vegetation response to drought, which contributes to the strong uncertainty on GPP and plant transpiration estimates and is critical for future projections. Moreover, LSMs represent different vegetation types by grouping plants with similar characteristics in terms of structure, behavior, and climatic conditions, therefore not accounting for possible differences in vegetation response to drought due to the diversity of environmental conditions within the same biome. In the ORCHIDEE LSM, we used in situ GPP and latent heat flux (LE) estimates at more than 40 sites from the FLUXNET Warm Winter 2020 network, which captures the recent drought years over Europe, to evaluate and refine the simulated vegetation response to soil water stress. We performed multisite data assimilation experiments based on the dominant vegetation type at these sites to optimize the parameters involved in vegetation response to soil water stress using the in situ GPP and LE estimates. We found that the optimized values of the coefficient that determines the speed of vegetation response to soil water stress can be defined as a function of the mean annual vapor pressure deficit (VPD). This new function enables to consider the environmental conditions on site through VPD in vegetation response to soil water stress, instead of having a response that only depends on the vegetation type. During a drought event, this soil water stress function induces vegetation growing under low VPD to close its stomata faster than vegetation acclimated to higher VPD conditions. Finally, regional simulations were performed to evaluate the impact of including this dependency on VPD in vegetation response to water stress over the recent European drought years.  
Efficacies, pattern effects & radiative feedback in a large ensemble of HadGEM3-GC3.1-LL historical simulations
Authors: Mutton Harry , Andrews Timothy , Hermanson Leon , Seabrook Melissa , Smith Doug , Ringer Mark , Jones Gareth , Webb Mark
Published: March 2024

Climate feedbacks over the historical period have been investigated in a 47 member ensemble of atmosphere-ocean general circulation model (AOGCM) simulations. Here, the model response to historical forcing, as well as individual forcing constituents such as aerosol and greenhouse gases separately, has been analysed. The analysis addresses the cause of differing feedbacks across the ensemble, the disparity between feedbacks seen in these AOGCM simulations and atmosphere-only GCM (AGCM) experiments prescribed with observed SSTs, and the different forcing efficacies of the respective forcing agents. It is found that much of the spread in feedbacks across ensemble members and different experiments can be explained through varying SST patterns. The level of polar amplification is shown to strongly control the amount of sea ice melt per degree of global warming, a mechanism responsible for the spread in shortwave clear sky feedback and a large contributor to the different forcing efficacies seen across the different forcing agents. The spread in feedbacks across the historical ensemble is also shown to be caused by both the level of tropical surface temperature warming, due to its influence on longwave clear sky feedback, and the response of  cloud feedbacks to local surface temperatures and large scale changes in tropospheric temperature. It is also shown that each of these processes discussed are partly responsible for the disparity in feedbacks seen between AOGCM simulations and  AGCM experiments prescribed with observed SSTs.
Improved ice cloud phase function for passive remote sensing
Authors: Joseph Romain , Fontaine Emmanuel , Vidot Jérôme
Published: March 2024

As part of the NWCSAF (Nowcasting Satellite Application Facility), the CNRM participates in the retrieval of cloud properties from geostationary satellite observations. These retrievals include the Cloud Mask and Cloud Types classification, thermodynamics properties at the macroscopic scales (Cloud Top Temperature and Height) as well as microphysical cloud properties (effective radius, optical thickness, liquid and ice water path). The cloud optical properties (including scattering, absorptions and emissions) are derived from cloud microphysical model in order to perform radiative transfer simulations. In this study, I combine cloud microphysical properties retrieved from DARDAR and in-situ observations with ERA-5 reanalysis to perform radiative transfer simulations with RTTOV. Hence, these simulation are compared with Meteosat Second Generation observations. Our goal is to identify the cloud properties that can affect the difference between observations and simulations in order to propose a new parameterization of the ice cloud scattering phase function in the radiative transfer model RTTOV (Radiative Transfer for TOVS).