bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental change and stratigraphy of the Upper Triassic sediment succession in Ras Al-Khaimah, UAE
Authors: Shah Azeem , Hennhoefer Dominik , Al-Suwaidi Aisha , Alsuwaidi Mohammed , Thomas Steuber Thomas
Published: March 2024

In the United Arab Emirates, the Late Triassic events including the Carnian Pluvial Episode are relatively poorly studied compared to the carbon isotope excursion and extinction event at the Triassic-Jurassic boundary. This study presents an integrated approach using geochemical and sedimentological data to investigate the depositional and environmental changes through the Late Triassic into the earliest Jurassic. Upper Triassic sediments exposed in Wadi Milaha consists of the marine Milaha and Ghalilah formations. The upper part of the Milaha Formation comprises limestone (predominantly mudstones and wackestones), with subordinate sandstone, marl and shale deposited in a shallow marine environment with some evidence of high-energy shoal deposition represented by ooidal and bioclastic grainstones and packstones. Clastic input varies cyclically and correlates with higher-order sea-level fluctuations. Faunal content includes bivalves, green algae, echinoderms, and benthic foraminifers, and suggests deposition in a shallow semi-restricted to open marine environment. Elemental proxies including Fe and Mn enrichment factors show widespread oxygen deficiency during the Late Norian on this equatorial shelf of Panthalassa. The Late Norian-Hettangian Ghalilah Formation is further broken into the Asfal and Sumra members. The first of these members is dominated by floatstones and rudstones with a higher content of coarse siliciclastics, indicating deposition in regressive conditions. The Sumra Member shows a decrease in coarse siliciclastics and an increase in mudstones, wackstones and packstones indicating a transgressive sea level cycle following the sequence boundary at the top of Asfal. The XRF elemental data also indicate fluctuations in clastic input throughout the Asfal and Sumra members indicative of increased weathering fluxes likely associated with a change to more humid conditions through the Late Triassic. A loss of fauna as well as ooidal grainstones are present at the top of the Sumra Member and continue into the Sakhra Member of the Ghalilah Formation indicating the well-documented extinction at the Triassic–Jurassic boundary. These new data from the equatorial margin of Panthalassa highlight significant environmental and climatic shifts through the Late Norian to Hettangian. 
Hydrological response to droughts in the Karnali basin of Nepal
Authors: Pokhrel Pranisha , Khanal Sonu , Griffioen Jasper , Bogaard Thom A. , Immerzeel Walter
Published: March 2024

The Karnali basin (40,000 sq km) in western Nepal is a pristine river basin with large potential for the development of hydropower and irrigation. The Karnali river sustains the biodiversity in the national parks downstream and supports the livelihoods of thousands of people. Any changes in the flow regime of the Karnali may therefore have far reaching consequences. This study focuses on analyzing the hydrological response of the Karnali to (multi-year) droughts. The objective is to understand how long the storages in the hydrological system, e.g. glaciers, snow, ground and soil water can buffer prolonged droughts. The hydrological model SPHY, calibrated with long-term river flow observations, is used for this purpose. We created synthetic drought time series by sampling from a 30-year historical forcing dataset based on ERA5. We then used these time series to force the SPHY model and we analyzed the change in streamflow composition as a function of drought duration. This study provides important insights in the buffering capacity of the river basin in a changing climate.
Comparison of developing WOFOST to model growth between typical fruit (chili pepper) and leafy (Chinese cabbage) vegetables
Authors: Tang Ruoling , Supit Iwan , Hutjes Ronald , Zhang Fen , Wang Xiaozhong , Chen Xuanjing , Zhang Fusuo , Chen Xinping
Published: March 2024

Most existed crop modelling studies are mainly cereal crops. Vegetables, the most economical and nutrient-dense crops, recieves insufficient attention, particularly on nutrient-uptake predictions. In open-field vegetable systems with shallower roots, shorter lifespan, and higher nutrient requirements, it is even more challenge to minize water pollution from fertilizers. To ensure both food and environment security, there is an urgent need of precise vegetable models to optimize productivity against fertilizer usage.We adapted the WOrld FOod STudies (WOFOST) crop growth simulation model for chili pepper (Capsicum annuum L.)  and Chinese cabbage (Brassica rapa L.) to support better fertilizer management under various climate and soil conditions. We conducted field experiments with six various fertilizer strategies (etc., mixed synthetic and organic fertilizers, denitrification products, and slow-control-release fertilizers) in southwestern China from 2019 to 2021. In total about 20 parameters relevant to physiological development, dry matter accumulation, photosynthesis, and nutrient uptake were measured and used in model adaptation.Our study shows that it is possible to model chili pepper’s growth without changing much from the WOFOST-generic model structure. We provide solutions by adapting user-defined developmental stages to mimic the growth from transplanting to fruiting and subsequently ripeness. As for WOFOST-Chinese cabbage, we further modify the phenological module to mimic the special vernalization habits of Chinese cabbage. Additionally, we design a new data re-analyzation method for accurate biomass partitioning predictions. Overall, both WOFOST-Chili and WOFOST-Chinese cabbage models show good model performance on biomass assimilation (rRMSE = 0.23/0.17 for chili/cabbage leaf dry weight; rRMSE = 0.06/0.17 for chili/cabbage storage organ dry weight) and nutrient uptake (rRMSE = 0.46/0.29 for chili/cabbage leaf N amount; rRMSE = 0.12/0.41 for chili/cabbage storage organ N amount). Besides, an improved leaf area index (LAI) simulation is found in WOFOST-Chinese cabbage (rRMSE = 0.11) than WOFOST-Chili (rRMSE = 0.76).These findings improve our understanding of yield-nutrient interactions within crop models, provide insights on expanding application of original-designed-for-field crop models to different vegetable versions, also call for a refined dynamic nutrient simulation flow within soil module to evaluate mitigation effect of expanded fertilizer strategies under climate change.
Why can nighttime convection occur despite strong convective inhibition?
Authors: Kuo Yi-Hung , Tan Zhihong , Zhao Ming , Neelin J. David
Published: March 2024

Over continental plains, precipitation tends to peak in the late afternoon or during nighttime. The accurate simulation of the land precipitation diurnal cycle in GCMs has been a long-standing challenge. Nighttime surface cooling tends to yield a stable layer with large convective inhibition (CIN). However, CIN arises from traditional parcel considerations—measuring the inhibition for an infinitesimal parcel. Here, we argue that the CIN layer is less effective in inhibiting convection than previously thought for convective entities of typical horizontal cloud size.A time-dependent process model for anelastic convective entities (ACE) is formulated to consistently include dynamic entrainment/detrainment as well as a representation of nonhydrostatic perturbation pressure. Spatially nonlocal effects mediated by the pressure field imply that horizontal feature size becomes a factor in the vertical conditional instability problem. ACE simulations using nighttime GoAmazon soundings with strong surface inversion demonstrate that the vertically nonlocal pressure response and its interaction with the surface boundary condition make the CIN layer ineffective for convective features of substantial horizontal size. Within the convective column, buoyancy of different signs offset each other via the nonlocal interaction over vertical scales comparable to the typical horizontal scale. Furthermore, the interaction with the surface tends to downweight the effectiveness of negative buoyancy contributions at low levels. This implies that a much smaller vertical velocity perturbation (or more generally, nonlocal buoyancy forcing from neighboring disturbances) can tunnel through the CIN layer. The same effect yields smaller magnitude for the mass flux above the CIN layer compared with steady plume models. A related implication of including spatially nonlocal interactions is that the vertical acceleration due to deep-convective buoyancy tends to extend above the level of neutral buoyancy (LNB). This results in cloud top much higher than the LNB, exhibiting the convective cold-top feature previously noted in observations. Results here point to revision for convective parameterizations. 
Hybrid Deep Learning Approach for Simultaneous Feature Engineering and Explanation of Water Quality Sensor Data 
Authors: Shin Jihoon , Kim YoungWoo , Park Taeseung , Cha YoonKyung
Published: March 2024

Water quality monitoring plays a crucial role in establishing effective management strategies for ensuring the safety and sustainability of water resources. Recently, with advances in sensor technologies, autonomous water quality monitoring has been increasingly used to obtain detailed temporal variations of water quality in the river network. However, irregular time series data are prevalent in multi-sensor monitoring systems and the resulting missing values limit the ability of data to serve as a decision basis. A modeling tool that can efficiently handle irregular time series data is required to derive useful insights from the sensor data. The combined use of feature engineering and attention mechanisms has shown benefits in dealing with irregular time series data from improved performance and explainability. In this study, hybrid deep learning that incorporates reverse time attention and trainable decay mechanisms (RETAIN-D) was used to analyze sensor data collected from multiple sites located in the upper section of the Geum River, South Korea. RETAIN-D was developed to predict the variations in the level of chlorophyll-a (Chl-a) concentrations and to analyze spatiotemporal associations between its influencing factors at different monitoring sites. RETAIN-D showed a high degree of accuracy (Accuracy = 0.81–0.90, AUC = 0.67–0.90, F1 score = 0.87–0.88 for test sets) for various chlorophyll-a standards. Trainable decay mechanism in RETAIN-D allowed predictions of Chl-a level in missing periods without manual feature engineering. Chl-a concentrations from the nearest adjacent tributary had high importance in predicting Chl-a levels for the target site. The contribution of input features among different time steps was generally higher in the recent time steps. These results demonstrate the usefulness of the hybrid deep learning approach as an efficient Big Data analysis tool for water quality and resource management.
Future evolution of coral reef carbonate production from a global climate-coral reef coupled model
Authors: Bouttes Nathaelle , Kwiatkowski Lester , Bougeot Elodie , Berger Manon , Brovkin Victor , Munhoven Guy
Published: March 2024

Coral reefs are currently under threat due to climate change and ocean acidification. However, future atmospheric CO2 levels, climate change and associated impacts on coral reefs remain uncertain. Critically, corals not only respond to atmospheric and climatic conditions but modify them. The calcification of corals modifies the concentration of dissolved inorganic carbon and total alkalinity in the upper ocean, impacting air-sea gas exchange, atmospheric CO2 concentrations, and ultimately climate. These feedbacks between atmospheric conditions and coral biogeochemistry can only be accounted for with a coupled coral-carbon-climate model.To simulate coral-mediated climate-carbon interactions, we have implemented a coral reef calcification module into the iLOVECLIM Earth system model of intermediate complexity. We then performed an ensemble of 210 parameter perturbation simulations to derive carbonate production parameter values that optimise the simulated distribution of coral reefs and associated carbonate production rates. The tuned model simulates the presence of coral reefs and regional-to-global carbonate production values in good agreement with data-based estimates. We have used this new coupled model to project future changes in coral reef carbonate production. The use of a computationally efficient intermediate complexity model allows us to cover a large range of possible futures that encompass different emissions scenarios (SSPs), climate sensitivities (hence different levels of warming) as well as the possibility of coral reefs adapting to higher SSTs which would reduce the risk of bleaching. We found a high sensitivity of the simulations to the ability of corals to adapt to thermal changes and to climate sensitivity, with the possibility of 20 to 100% coral extinction in scenario SSP1-2.6 depending on these parameters. This highlights the importance of improving the constraints on these factors in models and observations.
A Qualitative and Quantitative Evaluation of the WRF Model Simulations for High Resolution Urban Rainfall Forecasting 
Authors: Kusuman Karthika , Pentakota Likhitha , Kishore Nruthya , Gaddam Nagaraju , Rishika Ananthula , Mujumdar Pradeep P. , Bhowmik Rajarshi Das
Published: March 2024

In the past decade, there has been an increment in the magnitude and frequency of severe flood events across Bangalore city due to rise in rainfall intensities, increase in urban population, and drastic changes in urban landscape. The effect of urban development in a rapidly growing city has a substantial impact on the urban environment, leading to frequent flooding during monsoon and post-monsoon. Hence, a reliable forecasting system for rainfall at an urban scale is of priority to enhance the preparedness for disaster management. In this regard, a framework is developed for Bangalore City to dynamically downscale the daily rainfall prediction from National Centers for Environmental Prediction-Global Forecast System (NCEP-GFS) to high-resolution rainfall predictions, 3 km and 1 km spatial resolutions at 15-minute interval, employing the Weather Research and Forecasting (WRF) model. The model utilizes the initial and the boundary conditions forced at 06 UTC, resulting in a 24-hour lead-time forecast. The primary objective of this study is to test the performance of high-resolution WRF forecast with respect to the observed rainfall, using qualitative and quantitative statistical skill scores for the monsoon of 2023. Rank probability score at the municipal administrative level and performance indices such as critical success index, bias score, heidke skill score, false alarm ratio, and probability of detection at grid level are used for qualitative analysis. Whereas, quantitative measures are coefficient of determination, correlation, root mean square error, mean bias, and mean absolute error at grid as well as station levels. These metrics are estimated for various rainfall events and for different lead times. The study found that, the grid level correlation coefficient values for heavy rainfall events in 2023 fall in the range of 0.6 – 0.8 for the northern part of Bangalore city for both the spatial resolutions. Overall, our findings suggest that the forecasting framework can efficiently issue rainfall prediction with a lead time of 24 hours. This forecast can be further coupled with 1D and 2D hydrological models to predict flood inundation.
Active landslides inventory update based on EGMS data for slowing moving landslides in a hilly environment
Authors: Necula Nicușor , Niculita Mihai
Published: March 2024

The European Ground Motion Service (EGMS) products expand the InSAR utility in geohazards investigation, including mapping and monitoring various surface processes such as land subsidence, volcanic activity, landslides, etc. Access to such data is crucial, particularly for urban areas needing continuous monitoring of structures and infrastructures affected by landslides. Landslide deformations have become a significant threat in the context of climate change and global urbanization nowadays. The EGMS products offer consistent and reliable InSAR measurements of ground deformations with millimeter accuracy, which can be accessed and downloaded from the platform. The measurements include GNSS-calibrated full-resolution velocity and displacement time series for the ascending and descending orbits and calculated displacement vectors in the vertical and E-W directions, resampled to a 100 x 100 m grid. We focus on the slow-moving landslides with typical velocities of 16 mm/year, specific to the Moldavian Plateau, Eastern Romania. We exploit the ascending and descending full-resolution data for the 2016 – 2022 interval to identify the active landslides. Based on an existing landslide inventory extracted from high-resolution LiDAR DEM, we analyze the moving landslide of the current inventory.
Energetic charged particle observations of Europa’s near-space environment during the Juno PJ45 flyby and anticipations for the JUICE mission 
Authors: Clark George , Mauk Barry , Paranicas Chris , Brandt Pontus , Kollmann Peter , Smith Todd , Allegrini Frederic , Bolton Scott , Mitchell Don , Gkioulidou Matina , Barabash Stas , Wurz Peter , Krupp Norbert , Roussos Elias , Huybrighs Hans , Paty Carol , Jia Xianzhe , Khurana Krishan , Pontoni Angele
Published: March 2024

Jupiter’s moon Europa is of high scientific interest because it is an ocean world with a tenuous atmosphere and may also harbor sporadic water plumes. Europa is also embedded deep within Jupiter’s magnetosphere and resides in a harsh environment of radiation comprised of energetic-to-relativistic electrons and ions. Understanding the interplay between Europa and its near-space environment is key to unlocking the mysteries on how energetic particles contribute to surface weathering processes and how the moon itself and the neutral gasses that surround its orbital region contribute to energetic charged particle dynamics (e.g., acceleration and losses). In this presentation, we report on energetic particle observations made by Juno/JEDI during the PJ45 close flyby of Europa and discuss implications for the Particle Environment Package (PEP) instrument suite onboard ESA’s JUICE mission.
Model-based drought indicators improve the reliability of crop yield simulations with a statistical model in Poland
Authors: Eini Mamad , Conradt Tobias , Piniewski Mikołaj
Published: March 2024

Various inputs can be selected to establish a robust crop yield simulation based on statistical models. Typically, weather variables such as precipitation, temperature, relative humidity, etc., are used as inputs in these models. It is well known that drought is a major limiting factor for crop yield in Central Europe, as manifested in recent years. This study aimed to assess whether adding model-based drought indicators derived from a nationally calibrated and validated process-based agro-hydrological model (Soil and Water Assessment Tool - SWAT) could help increase the predictive power of crop yield prediction. The secondary objective was to assess future projections of crop yield. We considered two drought indicators: the Standardized Precipitation Index (SPI) and the Soil Moisture Index (SMI) with the following accumulation periods: 1970-2019. The ABSOLUT v1.2 (Assessing Best-predictive Sets fOr multiple Linear regressions throUgh exhaustive Testing) model was applied for the prediction of yield of major crops in Poland: winter wheat, spring barley, potatoes, sugar beet, and maize for 16 provinces of the country for the time period 1999-2019. ABSOLUT v1.2 is an adaptive algorithm that utilizes correlations between time-aggregated weather variables and crop yields for yield simulation. Future yield projections were derived based on bias-corrected EURO-CORDEX simulations driven by two Representative Concentration Pathways (RCPs), RCP4.5 and 8.5, corresponding to the radiative forcing levels of 4.5 W/m−2 and 8.5 W/m−2 in the year 2100, respectively. Our results indicate that incorporating drought indicators as predictors in statistical crop yield simulations slightly enhances the reliability of yield prediction in Poland. Projected crop yields reveal that in western parts of Poland, crop yields could experience a decrease of 8%, but in eastern parts, crop yields remain mostly unchanged.
Effects of EU policy and climate change on future delivery of nutrients to European seas
Authors: Grizzetti Bruna , Udias Angel , Vigiak Olga , Pistocchi Alberto , Aloe Alberto , Bisselink Berny , Bouraoui Faycal , De Meij Alexander , Hristov Jordan , Macias Moy Diego , Pisoni Enrico , Trichakis Ioannis , Weiss Franz , Zampieri Matteo , Zanni Michela
Published: March 2024

In Europe, intensive agriculture and high population density pose pressures on water resources quality and quantity. Water abstractions, intensive agriculture and wastewaters from urban areas and industries modify natural water availability and quality. The excess of nutrients (nitrogen and phosphorus) in rivers, lakes, groundwater and coastal waters impair water quality for human and ecosystem, and damage the goods and services provided by aquatic ecosystems. Environmental policy have been in place in the EU since the 1990s to reduce nutrient pollution and ensure sustainable water resource management and ecological quality, aiming at restoring and protecting all water bodies (2000/60/EC Water Framework Directive, WFD). Moreover, in recent years the ambitious goal to halve nutrient losses to the environment have been set by the EU Green Deal, Zero Pollution and Biodiversity Strategies. However, achieving this goal might require changes in the current land and water resource management.Climate change, with shifts in amount, seasonal distribution, and intensity of rainfall, soil moisture regime, and runoff events, affects delivery of nutrients to the fresh and marine waters. In this study, by mean of scenario modelling, we explore the possible combined effects of EU policy measures and climate change on nutrients delivery to European seas at the time horizon of 2050 compared to current condition in Europe. We discuss on the one side the expected impacts of main EU policies (such as the Common Agricultural Policy (CAP), the updated legislation addressing greenhouse gases emissions (Fit For 55 package), and the revision of the Urban Waste Water Treatment Directive UWWTD), and on the other side we look at the concurrent role of climate change (scenario RCP 4.5) on nutrient load delivered to European seas, considering regional variability.This study helps understanding the future trajectories of nutrient pollution in European fresh and coastal waters, highlighting the respective contribution of policy measures and climate change at the regional scale.
Navigating Hydroclimatic Extremes: Understanding the Interplay of Climate Change and Variability
Authors: Singh Achala , Sharma Priyank J. , Teegavarapu Ramesh S. V.
Published: March 2024

Increased frequency of extreme and rare hydroclimatic events leading to substantial disruptions in hydrological patterns worldwide can be attributed to climate variability and change. The stationarity assumption routinely used for hydrologic design and water resources planning is no longer valid under an evolving climate. Conventional notions about hydrological stability are now challenged, considering the intricate connection between climate fluctuations and the rising prevalence of extreme weather events. High spatial and temporal variability of extreme events in tropical and semi-arid climatic regions pose challenges in assessing non-stationarity considering available data and understanding processing contributing to short and long-term changes in regional climate. This study proposes and evaluates a novel approach using nonparametric statistical tests to explore the presence of non-stationarity in hydroclimatic extremes for a tropical river basin. Further, changes in the return levels of hydroclimatic extremes under stationary and non-stationary conditions will be carried out using statistical modelling approaches. Using the proposed approach, the identification of pivotal climatic drivers, such as oceanic oscillations and atmospheric circulation patterns, and their roles in influencing hydroclimatic extremes is possible. Long-term observational data is assessed in this work to discern trends and patterns in frequency, intensity, and spatial distribution of extremes and their links to climate change and variability. The impact of shifting precipitation patterns, temperature extremes, and seasonal variations is evaluated. This research study helps to investigate the implications of climate-induced hydroclimatic extremes under diverse geographical and climatic settings. This research can help understand the impact of climate change in river basins driven by the shifts in precipitation, temperature patterns, and extremes and address water availability and management issues.Keywords: Non-stationarity, Hydroclimatic extremes, Climatic drivers, Statistical modelling, Tropical River basin.
Examining Depth Origin of Anisotropy in an Active Orogenic Belt of Taiwan Using Shear Wave Splitting Results from the Formosa Array.
Authors: Gupta Ratna Mani , Huang Hsin-Hua , Chen Po-Fei , Lin Cheng-Horng , Peng Cheng-Chien
Published: March 2024

The Taiwan orogenic belt originates from the collision between the Philippine Sea Plate (PSP) and the Eurasian Plate (EU) with a subduction polarity reversal. The reversal around northern Taiwan creates a complex geodynamic process from subduction waning to post-collision extension. We study the deformation fabric with the shear wave splitting (SWS) method to unravel this tectonic complexity using multiple core phases (PKS, SKS, and SKKS, hereafter XKS). Prevailing SWS research acknowledged the presence of orogen-parallel anisotropy. However, recent studies with numerical modeling and coherency analysis suggested that the anisotropy source is in the asthenosphere. A recent dense seismic array (Formosa Array) of 148 seismic stations in northern Taiwan enables us to revisit this debate with improved spatial and back azimuthal coverage of the SWS measurements. The results show distinct variations in fast direction (Φ) from different back-azimuths and a much larger average delay time (dt) of ~2 sec compared to that derived from local subduction events (at 100-250 km depth). Application of the Fresnel zone and spatial coherency analysis also support an asthenospheric source for the observed anisotropy. The findings emphasize the need for depth-source analysis of anisotropy to better elucidate the responsible mechanisms of complex tectonic settings.
State of the art in science and technology for unique and lengthy administrative procedures - How does it work?
Authors: Schneider Susanne , Kause-Berg Harriet , Baasch Florian
Published: March 2024

In Germany disposal of low- and intermediate level radioactive waste is intended and took place in deep geological repositories. Two repositories in very different stages of their life cycle exist in Germany, both are disused mines. For the ERAM repository (Endlager für radioaktive Abfälle Morsleben) decommissioning and closure is expected to start in 2029. Radioactive waste was last stored in 1998. For the KONRAD repository (Schachtanlage Konrad) commissioning and storage of radioactive waste is anticipated in 2030. The respective permits regulate, how the final repository is designed, what protective measures must be taken, which waste may be stored in what form and how the final repository is to be closed. ERAM and KONRAD were approved in 1986 and 2002, respectively; both approval processes took place in previous decades. Since then, both repositories have been continuously adapted to the current state of the art in science and technology. But what is the “current state of the art in science and technology”, who defines it and what does it mean for the approval of deep geological repositories? In this contribution we will show examples of how the state of the art in science and technology finds its way into supervision and licensing activities and which actors are involved. Finally, we discuss how we could optimize these processes and what we might learn for the permission of a repository for high radioactive waste.
Io's topography on the basis of JunoCam images
Authors: Eichstädt Gerald , Orton Glenn S. , Hansen-Koharcheck Candice , Guillot Tristan , Becker Heidi , Bolton Scott J.
Published: March 2024

Juno's close approach of Io, during the inbound branch of the Perijove-57 Jupiter flyby, allowed Juno's visible light imager, JunoCam, to take a short sequence of close-up Io images at a cadence of about one minute. Consecutive images cover overlapping areas on Io from different angles. The parallax effect is definitely perceptible for several of the highest mountains. The images also show shadows cast by some of the mountains onto their much flatter surroundings. Varying shading, to be distinguished from albedo and color variability, returns small-scale inclination data.  Mountains imaged near Io's limb reveal distinctive silhouettes.  We use all these ingredients to retrieve relative elevation data from JunoCam's close-up Io images.  We will summarize  the available data, the applied methods, and our derived digital terrain results.
A deep learning-based earthquake simulator: from source and geology to surface wavefields
Authors: Lehmann Fanny , Gatti Filippo , Bertin Michaël , Clouteau Didier
Published: March 2024

Recent advances in scientific machine learning have led to major breakthroughs in predicting Partial Differential Equations’ solutions with deep learning. Neural operators, for instance, have been successfully applied to the elastic wave equation, which governs the propagation of seismic waves. They give rise to fast surrogate models of earthquake simulators that considerably reduce the computational costs of traditional numerical solvers.We designed a Multiple-Input Fourier Neural Operator (MIFNO) and trained it on a database of 30,000 3D earthquake simulations. The inputs comprise a 3D heterogeneous geology and a point-wise source given by its position and its moment tensor coordinates. The outputs are velocity wavefields recorded at the surface of the propagation domain by a grid of virtual sensors. Once trained, the MIFNO predicts 6.4s of ground motion velocity on a domain of size 10km x 10km x 10km within a few milliseconds.Our results show that the MIFNO can accurately predict surface wavefields for all earthquake sources and positions. Predictions are assessed in several frequency ranges to quantify the accuracy with respect to the well-known spectral bias (i.e. degradation of neural networks’ accuracy on small-scale features). Thanks to its efficiency, the MIFNO is also applied to a database of real geologies, allowing unprecedented uncertainty quantification analyses. This paves the way towards new seismic hazard assessment methods knowledgeable of geological and seismological uncertainties.
Estimating the sensitivity of continental aridity to global warming using Budyko’s framework
Authors: Chauhan Tejasvi Ashish , Kleidon Axel
Published: March 2024

Understanding the sensitivity of continental atmospheric aridity, the ratio of potential evaporation to precipitation in Budyko’s framework, to changes in temperature can help in quantifying the changes in the hydrological cycle and its extremes like droughts and floods in response to global warming. With rising temperature, land warms up faster than the ocean due to its different response of surface energy balance to diurnal changes in solar radiation. Thus, the potential evaporation, which represents atmospheric moisture demand, increases more over the land than the ocean. At the same time, global warming induced changes in the temperatures over land and ocean regions can alter the moisture supply to the atmosphere affecting the precipitation over land. Therefore, the sensitivity of continental atmospheric aridity to global warming is a superposition of relative changes in continental potential evaporation and precipitation in response to rising temperatures in both land and ocean regions. This work introduces an analytical framework based on Budyko’s aridity index to quantify the historical changes in continental aridity, and its sensitivity to global warming. We evaluate the proposed framework using observation-based datasets and our preliminary findings suggest that while changes in both potential evaporation and precipitation contribute to increase in the continental aridity with global warming, the relative changes in potential evaporation contribute more than relative changes in precipitation. These results point to the importance of considering both facets of aridity and highlight the utility of the Budyko’s framework in evaluating changes in hydrological cycle amid global warming.
Land surface hydrological modeling: do we really need complex model formulations?
Authors: Ackerer Philippe , Luttenauer David , Dell'Oca Aronne , Guadagnini Alberto , Weill Sylvain
Published: March 2024

Land Surface Models (LSM) grounded on physically-based mathematical models for energy and water balance can be characterized by various levels of complexity, especially when they integrate numerous processes. Diverse mathematical models (i.e., sub-models) can sometimes be formulated for some processes, due to different assumptions made during the system conceptualization stage. Therefore, running LSMs require (i) selection of a set of processes and related mathematical formulations that will be used and (ii) estimation of the corresponding parameters. A convenient way to guide model (and parameter) choice is to rely on global sensitivity analysis. In this work, we analyze sensitivity of 3 common hydrological outputs (evaporation, transpiration, and groundwater recharge fluxes) to models and parameters involved in typical LSMs. The global sensitivity analysis relies on random (Monte Carlo) sampling of values of parameters associated with each of the different formulations considered for the sub-models embedded in the LSM. This enables us to quantify the relative importance of process formulation and ensuing parameters. Three diverse indices based on (i) the whole (sample) probability density function (pdf) of the model output (Borgonovo et al., 2011) and (ii) the first and second moment of the pdf (corresponding to the moment-based sensitivity indices introduced by Dell’Oca et al. (2017)) are used. The joint use of these metrics is exemplified upon relying on realistic field conditions (in terms of, e.g., climate, vegetation, and soil type) associated with two watersheds in the Vosges region (France). Results show that sensitivity analysis plays a crucial role in identifying sub-models and parameters that contribute significantly to the uncertainty of model outputs. It is found that the main characteristics of the soil comprising the litter layer and root zone play an important role in the evaluation of the evaporation and groundwater recharge fluxes. As such, our results strengthen the need for targeted studies on the characterization of flow in these layers. Borgonovo et al., https://doi.org/10.1111/j.1539-6924.2010.01519.x, 2011.Dell’Oca et al., https://doi.org/10.5194/hess-21-6219-2017. 
Future Slower Reduction of Anthropogenic Aerosols Enhances Extratropical Ocean Surface Warming Trends
Authors: Gu Pingting , Gan Bolan , Cai Wenju , Wang Hai , Wu Lixin
Published: March 2024

Global surface temperature short-term trends fluctuate between cooling and fast-warming under the combined action of external forcing and internal variability, significantly influencing the detectability of near-term climate change. A key driver of these fluctuations is anthropogenic aerosols (AAs), which have undergone a non-monotonic evolution with rapid reduction in recent decades. However, their reduction is projected to decelerate under a high carbon emission scenario, yet the impact on surface temperature trends remains unknown. Here, using initial-perturbation large ensembles and signal-to-noise-maximizing pattern filtering method, the emergence timescale is assessed as an indicator for the detectability of externally-driven surface temperature trends across varying temporal spans, which signifies the predominance of externally-forced signals over internally-generated noises. We find that future slowdown in AA reduction across the extratropical Northern Hemisphere expedites the subpolar North Atlantic surface warming by intensifying the Atlantic meridional overturning circulation, enhancing the detectability of externally-driven surface temperature trends over a span of three decades. Further, such slower AA reduction over extratropical Northern Hemisphere accelerates the South Indian Ocean and Southern Ocean surface warming through positive low-cloud feedback and oceanic dynamical adjustment. It is triggered by the southward migration of the Southern Hemisphere westerlies under interhemispheric energy constraint. These AA-driven warmings exacerbate greenhouse warming, significantly enhancing the detectability of local decadal warming trends. Upholding stringent AA mitigation policies is imperative for effectively mitigating the risk of severe ocean warming.
Elucidating the formation and conversion mechanisms of HONO and HNO3 in the atmosphere of Daejeon, Korea
Authors: Kim Kyoungchan , Lee Chunsang , Choi Dayeong , Han Sangwoo , Eom Jiwon , Joo Hungsoo , Han Jinseok
Published: March 2024

Nitrogen oxide (NOX) in the atmosphere causes oxidation reactions with photochemical radicals and volatile organic compounds, causing ozone (O3) accumulation. In the composition of NOy, NOX accounts for the highest portion, and followed by nitrous acid (HONO) and nitric acid (HNO3). HONO significantly contributes to the reaction cycle of NOX and hydrogen oxide (OH). The generation of OH radicals and nitric oxide by photolysis is the main HONO removal mechanism in the morning. The OH radicals generated at this time trigger O3 accumulation in the atmosphere, affecting photochemical smog in urban areas. HNO3 in the atmosphere is produced by the reaction between NO2 and OH during the day while N2O5 and H2O during night time. Aerosolization by heterogeneous reactions of HNO3 is the major mechanism of HNO3 reduction. Aerosolization (heterogeneous) reactions adversely affect humans and plants by increasing the secondary aerosol concentration in the atmosphere and lowering visibility; therefore understanding the conversion mechanism of HNO3 to aerosols is important. In this study, HONO, HNO3, and their precursor gases in the atmosphere were observed using parallel-plate diffusion scrubber-ion chromatography. And a 0-D box model simulated the compositional distribution of NOy in the atmosphere, and the formation reactions and conversion mechanisms of HONO and HNO3 were analyzed.Acknowledgments:This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute (KEITI) funded by the Ministry of Environment (MOE)
CFD simulation of smoke plumes emitted from an urban fire accident
Authors: Gonzalez-Perez Alejandra , Moon Woo-Sok , Kim Jae-Jin
Published: March 2024

The increasing occurrence of urban fires and their uncontrollable nature significantly impacts health, the environment, and infrastructure. Individual large-scale fires have the potential to emerge as significant sources, given their notable contribution to the total atmospheric emissions within a city. In this study, the smoke plume resulting from an actual building fire was simulated over an 8-hour particle emission period using a computational fluid dynamic (CFD) model. The emission parameters were estimated, taking into account the dimensions of the burned area and the materials involved. Initial and boundary conditions were established based on data from the local meteorological observation stations, and the estimated emissions were validated by comparing the simulated concentrations of particles with those measured at local atmospheric monitoring stations. The CFD model used in this study simulated the smoke plume dispersion and potential heat release every hour during the fire, analyzing its behavior in diverse wind conditions in a building congested area.AcknowledgmentsThis research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute (KEITI) funded by the Ministry of Environment (MOE).
Model-based evaluation of efficiency of electrolysis-enhanced in-situ bioremediation for trichloroethylene using tandem circulation well
Authors: Yang Shuting , wen Zhang , Zhu Qi , Yuan Songhu , Li Yiming
Published: March 2024

Aerobic bioremediation combined with electrolytic enhancement, stimulating the indigenous subsurface microflora to degrade TCE, in the recirculating system of groundwater and solute induced by tandem circulation well (TCW) is a novel in-situ remediation method which has been gradually valued for its great application prospects due its  environmental and economic advantages. Previous investigations have been limited to few laboratory experiments, and neither the evaluation of remediation efficiency nor the improvement methods in application were fully understood. This study developed a reactive transport model for in-situ TCE bioremediation, simulating TCW-induced groundwater recirculating system, aerobic biodegradation process of TCE and electrolytic enhanced oxygen supply. A regionalized sensitivity analysis (RSA) was conducted based on the experimental data to quantify the influences of parameters, reduce the number of parameters inverted and provide the value of reactive kinetic parameters for this model. Different simulation cases were conducted to investigate influence of operating parameters and well spacing for remediation efficiency. The results show that increase in both current and pumping rate can improve the degradation efficiency but has a maximum degradation capacity due the limitation of saturated DO concentration in wellbore. Through a quantitative characterization of solute mixing, the model demonstrated an optimal operating parameters index (αoptimal), helping to find the optimal ratio of current and pumping rate. The results of the influence of well spacing indicate that too close an injection/extraction well distance is detrimental to degradation efficiency and the current and pumping rate need to increase in the same proportion with the increasing remediation area to remain the optimal efficiency.
Rill erosion and its structural inter-field connectivity in the White Nile-Congo ridge region – two years of high frequency UAV monitoring
Authors: Wilken Florian , Fiener Peter , Batista Pedro , Cooper Matthew , Haist Jasmin , Muhindo Daniel , van Oost Kristof , Rueegg Martin , Doetterl Sebastian
Published: March 2024

Tropical Africa is globally one of the most sensitive regions for soil erosion and is characterised by an important yield gap. Rapid population growth is expected to triple food demands in Sub-Saharan Africa by 2050. These rising food demands need to be met by cropland that is highly prone to soil erosion. In particular, the White Nile-Congo ridge region between the DR Congo and Uganda is a hotspot for issues relating to food security linked to massive soil degradation due to steep terrain, highly erosive rainfall and low soil cover conditions. Despite its importance, most soil erosion studies in the region are based on plot or large-scale modelling studies. Both approaches lack information on inter-field connectivity processes, which are especially important in smallholder farming structures where the average field size is 0.1 ha. To address this, a UAV-based monitoring campaign was carried out over different cropland sites (two in the DR Congo and two in Uganda) at high spatial and temporal resolution. The campaign covered more than 500 individual fields which were monitored twice per month (for two years) using UAV-based aerial photography to get insights into event-based rill erosion processes and the role of landscape connectivity. The aerial photography data was classified according to its field condition: (i) vegetation covered, (ii) bare soil without signs of rill erosion, (iii) field with rill erosion. The results highlight the relevance of land cover patchiness due to smallholder farming structures on inter-field connectivity with rill erosion often discontinuing downslope across field boundaries. Therefore, rill development is highly localised and affects individual fields. We further conclude that rill erosion in the White Nile-Congo ridge region is not an episodic process but takes place regularly during the rainy season as a result of high frequency erosive rainfall (on average 20 erosive rainfall events per rainy season) falling on bare soil in fields that are left fallow for individual cultivation periods. Soil erosion dynamics in the study area are complex and controlled by processes that are challenging to be represented in large scale predictions on soil degradation.
Studying statistical dependency among short and persistent events – recent developments and application to mid-latitude circulation anomalies associated with heatwaves
Authors: Donner Reik V.
Published: March 2024

During the last years, the statistical analysis of compound extremes has gained increasing interest among the scientific community due to the multiple threats presented by such events to society, economy, and the environment. In many situations, the statistics of compound extremes is based on bivariate extreme value theory and measures provided by this framework. Such choice of statistical methodology may however not properly address two relevant aspects: the non-zero duration of such events (which can be rather persistent, e.g. in the case of droughts or heatwaves, which heavily violates the independence assumption of classical extreme value theory) and the fact that not all events of practical revelance can be described as cases falling into the tails of the distribution of some observable of interest.A general framework addressing the non-extremeness aspect is provided by event coincidence analysis (ECA), which quantifies the empirical frequency of co-occurring events of arbitrary types and allows ist comparison with the values for certain random null models like independent Poisson processes with prescribed event rates. While classical ECA is based on temporal point processes and hence may be criticized for not capturing the statistical characteristics of persistent events very well, I will present a new methodological variant, interval coverage analysis (InCA), as an alternative for specifically addressing co-occurrences of persistent events. In the limit of vanishing event durations, the new interval coverage rates of InCA are identical to the event coincidence rates provided by ECA. By allowing for mutual time shifts between the different types of events under study as well as a temporal tolerance regarding their respective timing, fixed and even distributed time lags can be taken into consideration.This presentation introduces and compares the basic methodological concepts behind both ECA and InCA (including their extension to studying multivariate and conditional dependency), and demonstrates an example of their respective application in geoscientific contexts. Specifically, the spatial patterns of dependency between the timing of heatwaves and large-scale circulation anomalies of the atmospheric jet stream in the Northern hemisphere is studied. The corresponding analysis reveals specific regions with elevated likelihood of heatwaves along with the emergence of a split (double-banded) jet stream, while the emergence of heatwaves is suppressed at the same time in other regions. The obtained results may thus guide further targeted research regarding the specific mechanisms leading to this regional differentiation in heatwave frequency.