bluuebunny/crossref_metadata_2025 huggingface dataset:
Geothermochronological insights into the Sierra Nevada de Santa Marta: provenance and exhumation through U-Pb and Fission Track in zircon
Authors: Dias Airton N C , Parra Mauricio , Chew David , Sales Antonio S W , Pereira Vinicius Q
Published: March 2024

New geo-thermochronological data from modern sediments of the Sierra Nevada de Santa Marta (SNSM), a prominent mountain range along the Caribbean-South America plate margin in northern Colombia is presented. We applied U-Pb and Fission Track analyses in detrital zircon to document the provenance, exhumation, the cooling histories across high (900-850 ºC) and intermediate temperatures (320-180 ºC). The Zircon Fission Track (ZFT) results show Cenozoic ages, predominantly between 65-15 Ma. Populations between 55 and 80 Ma come from regions with intermediate elevations of the river basins. In general, this is in agreement with the ancient history of exhumation through the ~300 °C isotherm in SNSM. These same data can be observed in its extension to the south, in the Cordillera Central (CC) in Colombia.  The youngest population, up to 35 Ma that occurs in SNSM, corresponds to sediment collected from elevations lower than 900 m and documents the accentuated exhumation resulting from the dismemberment and translation of the SNSM. This can be associated with transtension by the oblique convergence of the Caribbean plate. U-Pb results include Mesoproterozoic (1000-1500 Ma), Carboniferous (300-350 Ma), Jurassic (200-150 Ma), Triassic (250-200 Ma) and Upper-Cretaceous (100-70 Ma) populations. These results show a correlation with the basement, which is well marked during the Neoproterozoic and Jurassic. A spatial analysis by inverse methods including detrital ages and the spatial distribution of lithostratigraphic units is being developed to understand the spatial distribution of current denudation and its controls.
Prediction Skill and Practical Predictability Depending on the Initial Atmospheric States in S2S Forecasts
Authors: Inatsu Masaru , Matsueda Mio , Nakano Naoto , Kawazoe Sho
Published: March 2024

The hypothesis that predictability depends on the atmospheric state in the planetary-scale low-frequency variability in boreal winter was examined.We first computed six typical weather patterns from 500-hPa geopotential height anomalies in the Northern Hemisphere using self-organizing map (SOM) and k-clustering analysis. Next, using 11 models from the subseasonal-to-seasonal (S2S) operational and reforecast archive, we computed each model’s climatology as a function of lead time to evaluate model bias. Although the forecast bias depends on the model, it is consistently the largest when the forecast begins from the atmospheric state with a blocking-like pattern in the eastern North Pacific. Moreover, the ensemble-forecast spread based on S2S multimodel forecast data was compared with empirically estimated Fokker– Planck equation (FPE) parameters based on reanalysis data. The multimodel mean ensemble-forecast spread was correlated with the diffusion tensor norm; they are large for the cases when the atmospheric state started from a cluster with a blocking-like pattern. As the multimodel mean is expected to substantially reduce model biases and may approximate the predictability inherent in nature, we can summarize that the atmospheric state corresponding to the cluster was less predictable than others.
eLTER and its role of providing in-situ data to large scale research projects for modelling biodiversity dynamics
Authors: Wohner Christoph , Oggioni Alessandro , Tagliolato Paolo , Taubert Franziska , Banitz Thomas , Venier Sarah , Trembath Philip , Peterseil Johannes
Published: March 2024

The integrated European Long-Term Ecosystem, critical zone and socio-ecological Research (eLTER) is an emerging pan-European, in-situ Research Infrastructure (RI). Once fully established, it will serve multiple scientific communities with high-level central facilities and distributed well-instrumented eLTER sites. In the Horizon Europe project Biodiversity Digital Twin (BioDT), eLTER already plays the role of a provider for European datasets, in particular for the Grassland Dynamics prototype digital twin. Here, GRASSMIND, an individual- and process-based grassland model designed for simulating the structure and dynamics of species-rich herbaceous communities, including these communities’ responses to climate and management, is to be upscaled to model different local grassland sites across Europe. As the eLTER in-situ site network also comprises such grassland sites, the site registry DEIMS-SDR (deims.org) was used to identify relevant sites and contact the respective site managers and researchers to mobilise data. This selection process was aided by the machine-actionable data endpoints of eLTER also accessible using the Python and R packages, deimsPy and ReLTER, enabling script-based extraction and analysis. Collected and mobilised data is to be published on the persistent data storage B2Share and made centrally accessible through the eLTER central data node. Metadata about the resources is also available in RDF format, making them interlinked and accessible via a SPARQL endpoint. The data provided will enable stronger validation and improvements of the grassland simulations, and thus to better scientific insights and grassland management recommendations.
Anthropogenic heat island motivated by coal-burning plants and its dispersion on the air pollutants
Authors: Ma Yongjing
Published: March 2024

The anthropogenic activities are playing an increasingly important role in regulating the atmospheric environment and local climate, therefore, it is of great significance to explore the effects of large anthropogenic heat sources on the structure of the atmospheric boundary layer (ABL), as well as their dispersion on the air pollutants. In this study, high spatio-temporal resolution observations of the ABL structure within a large coal-burning steel plant were performed in Yuncheng city (Shanxi province) in July of 2021. Results revealed that the strong anthropogenic heats disturbed the thermodynamic and material structure of the ABL, resulting in vertically homogeneous air pollutants in the daytime and high concentration pollutants stored within the nighttime residual layer (RL). Moreover, a dry heat island was formed above the coal-burning plant at night due to the horizontally spatial thermal contrast with the surrounding fields and villages. The dry heat-island was generally generated after sunset and disappeared within 1-2 hours beyond sunrise, with 3-10°C higher and 30-60% drier than the neighboring areas. Large-eddy simulations constrained by the in-situ measurements show that the heat-island circulation can diffuse the plant-discharged pollutants to penetrate through the stable boundary layer and enter into the RL, horizontally spreading below the upper boundary of the RL and eventually forming a "mushroom cloud". The formation, size, and pollutant concentration of the “mushroom cloud” are significantly influenced by the dynamic wind speed and anthropogenic heat intensity. As the increase of the solar irradiance in the next day, the pollutants retained within the RL can be downward transported to the ground, leading to the morning peaks of various pollutants at the surface level, which were statistically found to be common phenomenons not only in the areas adjacent to the plant, but also in the major urban clusters across China.
An Integrated Hydrological Modeling Framework for Enhancing Water-Energy Nexus during El Niño Events in the Godavari River Basin, India 
Authors: Kasiviswanathan Kasiapillai S , Thakur Chandni
Published: March 2024

El Niño events pose a significant threat to water security in the Godavari river basin (GRB), leading to adverse impacts on water-energy nexus. To enhance long-term energy security, we developed an integrated framework combining the hydrological model, variable infiltration capacity (VIC) model, and geospatial tools to identify potential sites for run-of-river small hydropower (RoR-SHP) plants. The study utilized long-term (1951-2020) daily streamflow data, simulated with the VIC model for design discharge computation at 30%, 75%, and 90% flow dependability. The analysis revealed considerable potential for RoR-SHP development within the GRB, identifying 226 initial sites based on the head along the river, with a combined power and annual energy generation estimate of 92 MW and 0.4 TWh/yr, respectively, at 90% flow dependability. After meticulous screening, 11 potential sites based on the head and the power potential were identified. The detailed analysis during El Niño years demonstrated a decline of approximately 46%, 38%, and 18% in total annual energy at 30%, 75%, and 90% flow dependability, respectively, compared to normal years. Consequently, we proposed nine potential sites based on the head, power potential, and viability under El Niño for RoR-SHP development, capable of maintaining the firm power even during El Niño years. Our findings highlighted the increased risk of power shortages in the GRB during El Niño years, emphasizing the imperative need for implementing water-energy nexus strategies to cope with the risks associated with El Niño events.
Subglacial lake detection in Dronning Maud Land, East Antarctica using ICESat-2
Authors: Arthur Jennifer , van Oostveen Jelte , Shackleton Calvin , Moholdt Geir , Matsuoka Kenichi
Published: March 2024

Subglacial lakes beneath the Antarctic Ice Sheet are known to influence ice-sheet dynamics and form part of an extensive active hydrological network. Ice surface elevation anomalies from repeat-track altimetry can be useful for detecting subglacial lakes and the evolution of subglacial water transport towards sub-ice-shelf cavities. Here, we analyse a 5-year time series of laser altimetry data from the ICESat-2 satellite to investigate potential subglacial lake activity in the coastal Dronning Maud Land region of East Antarctica. Our results reveal ice surface uplift and subsidence events which we interpret to reflect the active draining and filling of subglacial lakes over annual timescales. We find lake locations to be topographically-controlled and coincide spatially with predicted subglacial water routing pathways. Our results highlight subglacial lake activity as close as 10 km from the grounding line in a region of East Antarctica where no subglacial water has been observed in the coastal zone previously. These findings bring knowledge of the dynamics and evolution of subglacial meltwater in this region and provide new observational data to refine subglacial hydrological model estimates of water flux towards ice-shelf grounding zones.
Resources to give facts a fighting chance against misinformation
Authors: Winkler Bärbel , Cook John
Published: March 2024

Skeptical Science is a volunteer-run website publishing refutations of climate misinformation. Some members of the Skeptical Science team actively research best-practices refutation techniques while other team members use the provided materials to share debunking techniques effectively either in writing or through presentations. In this submission, we highlight several of our publications and projects, designed to help to give facts a fighting chance against misinformation. While some of the resources are directly related to climate change such as the rebuttals to common climate myths, the employed techniques apply across different topics. They include the “FLICC-framework” which features a taxonomy of science denial rhetorical techniques (FLICC standing for fake experts, logical fallacies, impossible expectations, cherry picking, and conspiracy theories), the Debunking Handbook 2020 which summarizes research findings and expert advice about debunking misinformation, and the Conspiracy Theory Handbook distilling research findings and expert advice on dealing with conspiracy theories. We will also introduce the Cranky Uncle smartphone game,  which uses critical thinking, gamification, and cartoons to interactively explain science denial techniques and build resilience against misinformation.
Assessing Nitrous Oxide Emissions from Agricultural Soil: A Comparison of Two Grass-clover Proportions
Authors: Kong Meng , Petersen Søren O. , Eriksen Jørgen , Dold Christian
Published: March 2024

The inclusion of grass-clover (GC) leys in crop rotations on dairy farms may contribute to climate change mitigation by facilitating carbon sequestration in soils. A long-term experiment in Denmark found that soil organic carbon (SOC) and soil total nitrogen (STN) increased with the proportion of GC (i.e., 2 and 4 years of GC in a six-year rotation) from 2006 to 2020. However, the incorporation of GC residues may potentially increase nitrous oxide (N2O) emissions due to the increased SOC and STN stocks. Yet, limited information exists regarding N2O emissions with different proportions of GC. We hypothesized that N2O emission will increase with more GC years in the rotation. This study aimed to quantify the emissions of N2O in two long-term crop rotations with different proportions of GC years (1/3 or 2/3), and all crops present each year. A one-year experiment is currently conducted including the rotation year preceding, and the year following GC cultivation where spring barley is cultivated, in both crop rotations (n=2, total: 8 plots). Emissions of N2O were quantified starting from April 2023 (day of year, DOY 111). Surface N2O fluxes were measured with the LI-7820 N2O/H2O trace gas analyzer connected to the 8200-01S Smart Chamber (LI-COR Biosciences, Lincoln, NE, USA). Linear mixed models were used to analyze N2O with crop rotation (1/3 or 2/3 GC) and rotation year (pre- or post-GC) as fixed effects and sampling date and block as random effects. Preliminary results showed elevated N2O fluxes (up to 443 ug N2O-N m-2 h-1) with a longer high-flux period in post-GC rotation years (DOY 111-151), than pre-GC years (DOY 111-139). The highest cumulative emission was 420 mg N2O-N m-2 in the post-GC year of DOY 320 in 1/3 GC. For pre-GC in 1/3 GC, pre-GC and post-GC in 2/3 GC, emissions were 249, 341 and 252 mg N2O-N m-2, respectively. For both N2O fluxes and cumulative emissions, the 1/3 GC rotation was significantly higher (p
Spatial extent of rain-on-snow (ROS) events in the Arctic (Svalbard) : combining wet snow maps from TerraSAR-X and Radarsat Constellation Mission with ERA5 reanalysis, glaciological measurements, and optical Planet images
Authors: Dedieu Jean-Pierre , Momber Marion , Champagne Olivier , Wendleder Anna , Montpetit Benoit , Bernard Eric , Friedt Jean-Michel , Zolina Olga , Jacobi Hans-Werner
Published: March 2024

In the Arctic, extreme weather conditions such as rain-on-snow events (ROS) make the monitoring of the snowpack with remote sensing techniques increasingly relevant and necessary. In recent years, remote sensing methods based on active radar images (SAR) are well described for mapping the spatial extent of ROS events in the terrestrial Arctic (Vickers, 2022; Bartsch, 2023). However, few methods are proposed to validate the relationship between ROS and elevation for such events over glaciers likely due to the lack of in-situ measurement networks in these high latitude areas. Svalbard provides several meteorological and snow monitoring sites, which is a great value for detecting the occurrence of these ROS events and validation of the remote sensing methods.The purpose of this study is to investigate the spatial and temporal effects of recent ROS events over the Brøgger peninsula (210 km2) in Svalbard (N 78°55’ / E 11° 55’), using remote sensing methods, local meteorological measurements and reanalyses. For each ROS event of the 2017-2023 time period, remote sensing SAR maps of wet snow (Nagler and Rott, 2000) are produced from images obtained with the TerraSAR-X (DLR) and RCM (CSA) high resolution sensors (5-m), respectively at X- and C-band frequency.The validation of the affected areas is based (i) on ERA5 reanalysis data used to estimate the altitude of the 0°C isoline and (ii) on a network of temperature sensors installed on the Austre Lovén glacier. SAR maps, ERA5 isoline, and in-situ data are in good agreement, resulting in altitude differences between 10 and 25 m for the transition of wet and dry snow, depending on the event.Although optical images availability is limited due to polar night and cloud cover during precipitation, it was further possible to use optical Planet images at high temporal and spatial resolution (3-m) to determine the ROS impact after the events on the properties of the snow cover. The decreasing signal of the red-edge and near-infrared bands indicate higher snow densities and a stronger wetness of the snowpack, which closely aligns with in-situ observations through snow stratigraphy.
Impacts of irrigation on local, regional, and remote climate
Authors: Lo Min-Hui , Chen Hung-Chen
Published: March 2024

Irrigation significantly impacts climate across local, regional, and remote scales. This critical agricultural practice transforms local land surface properties, leading to increased soil moisture and consequent changes in the surface energy balance. Such changes typically result in cooler local surface temperatures due to higher latent heat flux from enhanced evapotranspiration. Beyond its local effects, irrigation substantially influences regional climate and hydrology. The introduction of additional moisture into the atmosphere from irrigated areas can alter regional atmospheric dynamics, potentially affecting cloud formation and modifying precipitation patterns. While irrigation practices can be beneficial for agriculture, they may also have unintended consequences on regional climates, including altering rainfall distribution. Furthermore, the implications of irrigation can extend to remote climate systems. Irrigation-induced redistribution of heat and moisture can influence atmospheric circulation patterns and atmospheric wave dynamics, impacting hydroclimate far beyond the immediate area of irrigation. These remote effects underscore the interconnected nature of global climate systems and the extensive impact of localized human activities like irrigation.In sum, irrigation exerts a cascading influence on climate systems at various scales. It reshapes local surface conditions, drives changes in regional atmospheric processes, and has potential implications for remote climates. Comprehending these complex interactions is crucial for formulating sustainable irrigation strategies and addressing the broader climatic impacts of such practices.
ACCESS-NRI: Supporting Climate Science through Robust Model Evaluation and Community-Driven Strategies
Authors: Beucher Romain , Tetley Michael G. , Zeng Yousong , Chun Felicity , Squire Dougal , Kaluza Owen , Druken Kelsey , Hogg Andy
Published: March 2024

The Australian Earth System Simulator (ACCESS-NRI) is a national research infrastructure designed to support the development and research of the Australian Community Climate and Earth System Simulator (ACCESS). With a strategic goal to enhance the quality and performance of the ACCESS suite of model configurations, ACCESS-NRI supports the open development and release of a Model Evaluation and Diagnostics (MED) framework for the Australian Earth system modeling community. 

In climate science, the evaluation of computational models plays a pivotal role in assessing their performance and reliability in simulating the Earth's complex climate system. This process involves a comprehensive analysis of model predictions against observed data to determine accuracy and utility. Through meticulous model evaluation, scientists gain insights into real-world climate processes, identify model strengths and weaknesses, and refine models to enhance predictive capabilities. 

Integral to international climate change assessments, climate models are crucial for shaping policies and guiding investments in climate action. Accurate simulations, reliant on precise modeling of climate physics and realistic forcing conditions, such as CO2 emissions, are fundamental to these endeavors. However, the development of these models is a protracted, iterative process requiring constant evaluation of performance and accuracy. Users seek to compare model simulations derived from diverse configurations, necessitating dedicated tools, workflows, and access to diverse data sources within high-performance computing environments. 

The development of tools and methods is integral to this initiative, providing essential support for the incorporation of model evaluation within code development cycles. The presentation explores community-driven strategies designed to streamline the evaluation of the ACCESS suite of models, addressing specific requirements and constraints associated with the World Climate Research Programme’s (WCRP) Coupled Model Intercomparison Project phase 7 (CMIP7) and its future iterations. Emphasis is placed on the incorporation of model evaluation within code development cycles. 

 
A Comprehensive Review of Coastal Compound Flooding Literature
Authors: Green Joshua , Haigh Ivan , Quinn Niall , Neal Jeff , Wahl Thomas , Wood Melissa , Eilander Dirk , de Ruiter Marleen , Ward Philip , Camus Paula
Published: March 2024

Compound flooding, where the combination or successive occurrence of two or more flood drivers leads to an extreme impact, can greatly exacerbate the adverse consequences associated with flooding in coastal regions. This paper reviews the practices and trends in coastal compound flood research methodologies and applications, as well as synthesizes key findings at regional and global scales. Systematic review is employed to construct a literature database of 271 studies relevant to compound flood hazards in a coastal context. This review explores the types of compound flood events, their mechanistic processes, and synthesizes the definitions and terms exhibited throughout the literature. Considered in the review are six flood drivers (fluvial, pluvial, coastal, groundwater, damming/dam failure, and tsunami) and five precursor events and environmental conditions (soil moisture, snow, temp/heat, fire, and drought). Furthermore, this review summarizes the trends in research methodology, examines the wide range of study applications, and considers the influences of climate change and urban environments. Finally, this review highlights the knowledge gaps in compound flood research and discusses the implications of review findings on future practices. Our five recommendations for future compound flood research are to: 1) adopt consistent definitions, terminology, and approaches; 2) expand the geographic coverage of research; 3) pursue more inter-comparison projects; 4) develop modelling frameworks that better couple dynamic earth systems; and 5) design urban and coastal infrastructure with compound flooding in mind. We hope this review will help to enhance understanding of compound flooding, guide areas for future research focus, and close knowledge gaps.
Arctic wetting: Performances of CMIP6 models and projections of precipitation changes
Authors: Cai Ziyi , You Qinglong
Published: March 2024

The Arctic region is experiencing a notable increase in precipitation, known as Arctic wetting, amidst the backdrop of Arctic warming. This phenomenon has implications for the Arctic hydrological cycle and numerous socio-ecological systems. However, the ability of climate models to accurately simulate changes in Arctic wetting has not been thoroughly assessed. In this study, we analyze total precipitation in the Arctic using station data, multiple reanalyses, and 35 models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6). By employing the moisture budget equation and an evaluation method for model performance with ERA5 reanalysis as a reference, we evaluated the models’ capability to reproduce past Arctic wetting patterns. Our findings indicate that most reanalyses and models are able to replicate Arctic wetting. However, the CMIP6 models generally exhibit an overestimation of Arctic wetting during the warm season and an underestimation during the cold season from 1979 to 2014 when compared to the ERA5 reanalysis. Further investigation reveals that the overestimation of wetting during the warm season is largest over the Arctic Ocean’s northern part, specifically the Canadian Arctic Archipelago, and is associated with an overestimation of atmospheric moisture transport. Conversely, the models significantly underestimate wetting over the Barents-Kara Sea during the cold season, which can be attributed to an underestimation of evaporation resulting from the models’ inadequate representation of sea ice reduction in that region. The models with the best performance in simulating historical Arctic wetting indicate a projected intensification of Arctic wetting, and optimal models significantly reduce uncertainties in future projections compared to the original models, particularly in the cold season and oceanic regions. Our study highlights significant biases in the CMIP6 models’ simulation of Arctic precipitation, and improving the model’s ability to simulate historical Arctic precipitation could reduce uncertainties in future projections.
Dealing with uncertainties related to ground motion prediction models for Georgia, Caucasus Region.
Authors: Jorjiashvili Nato , Shengelia Ia , Godoladze Tea , Gunia Irakli , Akubardia Dimitri
Published: March 2024

Georgia is situated in the Caucasus region, which is one of the most seismically active regions in the Alpine-Himalayan collision belt. Analysis of the historical and instrumental seismology of this region shows that it is still of moderate seismicity. The seismicity of the area reflects the general tectonics of the region.Recently, number of seismic stations and earthquake records in Georgia significantly increased. Thus, we can run more detailed studies regarding ground motion prediction. Ground motion prediction equations (GMPEs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. In this study ground motion prediction equations are obtained by classical, statistical way, regression analysis. Also, new data and new features such as local soil conditions, fault types, etc. were considered for analysis. In the study models are obtained for PGA (horizontal and vertical), 5%-damped pseudo-absolute-acceleration spectra (SA) are described for periods between 0.01 s and 10 s (for both vertical and horizontal components).Next stage was to assess the standard deviation and its minimization. Fuzzy Analysis gives a possibility of making optimal decision when available data is insufficient and cannot represent real situation. In our case it is quite difficult to explain all physical processes related to earthquakes. However, it is very important to consider all processes during the hazard assessment. Also, during GMPE assessment it is very difficult to consider site effect very precisely because available data is still insufficient. In this case usage of Fuzzy Analysis is the best solution. We constructed membership functions based on shear wave velocity measurements for each site class. Site classifications were done according to Eurocode8. At the end a significant reduction of uncertainties (~30-40%) was observed.
Generation and paths of internal waves on a tropical continental shelf
Authors: Dialectaquiz Arian , Dottori Marcelo , Mazzini Piero
Published: March 2024

Through wavelet analysis of temperature and current data, and remote imaging via Synthetic Aperture Radar and True Color, internal waves were identified in the South Brazil Bight (SBB). These waves have predominant semi-diurnal tidal frequencies as well frequencies associated with cold fronts.Through baroclinic energy flows and coarse graining kinetic energy budget calculated from results of the Regional Ocean Modeling System (ROMS), the energy cascade associated with this internal phenomenon was quantified, as well the contribution of topography in the generation of internal waves due to the instability of the internal tide.The internal energy paths on the shelf were discretized with the correlation of sub - and supratidal energy flows with the Barotropic - Baroclinic conversion, thus identifying energy conversion hotspots by topography, and the spatial variability in the generation and propagation of internal waves.The results indicate that while a supercritical regime of baroclinic tide generation prevails in the SBB, from the barotropic tide, with propagation towards the open sea, some regions on the continental shelf are close to a critical regime. In these areas, the lateral distance for the internal tide excursion is less than 5 km, which promotes shearing, local instability dissipation, and the generation of nonlinear internal waves. Simultaneously, in regions with a supercritical regime, subtidal frequency phenomena act as a force for internal waves towards the coast.
Topic Analysis and Classification of EGU Conference Abstracts
Authors: Klump Jens , Nguyen Chau , Hille John , Stewart Michael
Published: March 2024

The corpus of Abstracts from the EGU General Assemblies 2000 - 2023 covers a wide range of Earth, planetary and space sciences topics, each with multiple subtopics. The abstracts are all in English, fairly uniform in length, cover one broad subject area, and are licenced under a permissive licence that allows further processing (CC BY 4.0), making this a high-quality text corpus for studies using natural language processing (NLP) and for the finetuning of Large Language Models (LLM). Our study makes use of openly available NLP software libraries and LLMs.In the first phase of this study, we were interested in finding out how well abstracts map to the topics covered by EGU Divisions and whether co-organisation of sessions contributes to or dilutes topics. The abstracts are available only in unstructured formats such as Portable Document Format (PDF) or plain text in XML extracts from the conference database. They are identified by abstract numbers but carry no information on the session or division where they were originally presented. We reconstructed this information from the online conference programme.To be able to employ a supervised learning approach of matching abstracts to topics, we defined the topics to be synonymous with the 23 scientific divisions of the EGU, using the division and co-listed divisions as topic labels.We finetuned the Bidirectional Encoder Representations from Transformers (BERT) and the slightly simplified DistillBERT language models for our topic modelling exercise. We also compared the machine classifications against a random association of abstracts and topics. Preliminary results obtained from our experiments show that using a machine learning model performs well in classifying the conference abstracts (accuracy = 0.66). The accuracy varies between divisions (0.40 for NP to 0.96 for G) and improves when taking co-organisation between divisions into account. Starting from one year of abstracts (EGU 2015), we plan to expand our analysis to cover all abstracts from all EGU General Assemblies (EGU 2000 - 2024).
AIRETH 2.0 – a revamped helicopter-borne GPR for glaciological applications
Authors: Farinotti Daniel , Moser Raphael , Anhorn Barthelemy , Ogier Christophe , Bauder Andreas , Pohl Benedikt , Soja Benedikt , Maurer Hansruedi
Published: March 2024

The Airborne Ice Radar of ETH Zurich (AIRETH) is a dual-polarization, helicopter-borne GPR system that was developed for glaciological applications. At the core of AIRETH are two pairs of commercial, orthogonally oriented, bistatic dipole antennas operating at a center frequency of 25 HMz or higher. The system has extensively been operated in the past, e.g. for collecting close to 2,500 km of GPR data for estimating the ice thickness of glaciers across the Swiss Alps.Here, we present a series of amendments that have recently performed to the AIRETH system in order to increase its versatility and operability. The corresponding work notably included:1. a re-design of AIRETH’s air-frame, aiming at decreasing the system’s overall weight, as well as at increasing the system’s stability and ease of operation;2. a newly developed positioning system, which is now based on the integration of information obtained from a set of four low-cost Global Navigation Satellite System (GNSS) sensors placed at the corners of the main air-frame in combination with an Inertial measurement unit (IMU); and3. an experimental antenna shielding based on low-cost materials, aiming at minimizing the ringing noise caused by the proximity of the GPR system to the carrying helicopter.The contribution will focus on the advances that were achieved compared to the previous AIRETH setup, and will point out the challenges faced during system re-design. The capabilities of the new system will, moreover, be illustrated by presenting some recent datasets acquired over Alpine glaciers.
Spontaneous formation of OH oxidation products at the interfaces of pure organic droplets
Authors: Angelaki Maria , George Christian
Published: March 2024

There are now many evidence that OH and H2O2 can be spontaneously formed at the air – water interface of aqueous droplets due to the presence of a strong electric field (~109 V m−1). OH– anion has been suggested that it partially exist as an ion pair (OH...e-), which may undergo charge separation in the presence of this electric field. This can lead to OH radical and electron production, while H2O2 can be formed via subsequent reactions. The presence of organic molecules on aqueous droplet surfaces and the OH radicals that are spontaneously generated can lead to oxidation products formation altering the composition of the particles.In this work we studied the OH products formation of pure organic aerosols while they interact with water vapour. We investigated the product formation in the absence of OH radicals precursors, in the dark in the range of RH 0 – 100 %. Organic droplets, in a range of diameter 10 to 300 nm, were generated by nebulizing citric acid solutions. The particles passed through a diffusion dryer and entered inside a flow tube reactor. Particles were collected either on filters or by using a spot sampler. The particle phase analysis was performed via Ultra High-Performance Liquid Chromatography coupled with Electrospray Ionization Orbitrap Mass Spectrometry. Gas phase products were also monitored using a VOCUS mass spectrometer.All the experiments provide evidence that organic droplets can be oxidized while interacting with water vapours. No products were observed under dry conditions. Oxidation products were formed in the particle phase and their production displayed a systematic increase with the increase of RH denoting the enhancement of OH radical generation. At complete humid conditions, products were also observed in the gas phase due to their desorption. H2O2 was also monitored in the gas phase confirming that interfacial OH and electron generation can lead to its formation. Results from this study are expected to significantly improve our insights on the interfacial processes that occur in atmospheric droplets and on the atmospheric multiphase oxidation chemistry.
Predictive uncertainty analysis using null-space Monte Carlo 
Authors: Baalousha Husam , Fahs Marwan , Younes Anis
Published: March 2024

The inverse problem in hydrogeology poses a significant challenge for modelers due to its ill-posed nature and the non-uniqueness of solutions. This challenge is compounded by the substantial computational efforts required for calibrating highly parameterized aquifers, particularly those with significant heterogeneity, such as karst limestone aquifers. While stochastic methods like Monte Carlo simulations are commonly used to assess uncertainty, their extensive computational requirements often limit their practicality.The Null Space Monte Carlo (NSMC) method provides a parameter-constrained approach to address these challenges in inverse problems, allowing for the quantification of uncertainty in calibrated parameters. This method was applied to the northern aquifer of Qatar, which is characterized by high heterogeneity. The calibration of the model utilized the pilot point approach, and the calibrated results were spatially interpolated across the aquifer area using kriging.NSMC was then employed to generate 100 sets of parameter-constrained random variables representing hydraulic conductivities. The null space vectors of these random solutions were incorporated into the parameter space derived from the calibrated model. Statistical analysis of the resulting calibrated hydraulic conductivities revealed a wide range, varying from 0.1 to 350 m/d, illustrating the significant variability inherent in the karstic nature of the aquifer.Areas with high hydraulic conductivity were identified in the middle and eastern parts of the aquifer. These regions of elevated hydraulic conductivity also exhibited high standard deviations, further emphasizing the heterogeneity and complex nature of the aquifer's hydraulic properties.
Airy worlds or barren rocks? On the survivability of secondary atmospheres around the TRAPPIST-1 planets.
Authors: Van Looveren Gwenaël , Güdel Manuel , Boro Saikia Sudeshna , Kislyakova Kristina
Published: March 2024

JWST is currently at the forefront in the search for exoplanet atmospheres. However, the observation of atmospheres of Earth-like planets pushes the limits of the instruments, often requiring multiple observations to be combined. Their interpretation requires complementary theoretical studies to test plausible atmospheric models. We aim to determine the atmospheric survivability of rocky planets around late M-type dwarfs by modelling the upper atmosphere of the TRAPPIST-1 planets' response to incoming stellar extreme ultraviolet and X-ray (XUV) radiation. This is done using a self-consistent thermo-chemical code to create a grid of models simulating possible atmospheres. Specifically we study the atmospheric mass loss due to Jeans escape induced by XUV radiation. Our models indicate that even Jeans escape is catastrophically large for these N2 or CO2 dominated atmospheres over evolutionary timescales, which has important observational implications.
Temperature dependent rate coefficients of the OH reaction with methacrolein and of the 1,4 H-shift reaction of the organic peroxy radical from methacrolein
Authors: Fuchs Hendrik , Berg Florian , Dubus Rene , Vereecken Luc , Wahner Andreas , Novelli Anna
Published: March 2024

We present the measurement of the temperature dependent rate coefficient of the OH reaction with methacrolein between 280 and 340 K using an OH reactivity instrument that allows to accurately determine the loss rate of OH reactants. Experiments were performed in synthetic air (presence of oxygen). In the case of methacrolein, OH radicals are regenerated by the 1,4 H-shift reaction of the aldehyde group of the MACR-1-OH-O2 radical which is the main peroxy radicals formed its OH reaction. Therefore, the observed OH decay deviates from a single-exponential decay expected from a pseudo-first order loss reaction. This allows to determine the rate coefficient of the peroxy radical isomerization reaction using model calculations, in which reaction rates are optimized to best describe the observed OH radical decay. This method is one of few direct measurements of atmospherically relevant peroxy radical isomerization reaction coefficients that have been reported in literature so far. Experimentally derived values are compared to quantum-chemical calculations of the 1,4 H-shift reaction rate and to rate coefficients reported in literature for the isomerization reaction and the OH reactions of methacrolein.
A conceptual model for alluvial fan formation and development 
Authors: Lehmkuhl Frank , Owen Lewis A.
Published: March 2024

The development of alluvial fans is sensitive to environmental change and, thus, alluvial fans provide essential archives for reconstructing Quaternary paleoenvironmental conditions, particular climate, hydrology, and tectonics. Although alluvial fans have been studied across the globe for over a century, there is no unifying scheme/framework or model to consider their complete variety and mode of formation. By reviewing the global spatial and temporal range of alluvial fan types and data from selected key dryland regions, we are able to develop a conceptual scheme/framework for their geomorphology and formation, and thus aid in their application for Quaternary climate and environmental change studies. This approach suggests that there are three main regimes for alluvial fan geomorphology and formation: Type I) microscale mountain alluvial fans, small in size and extent (radius < a few 100 m); Type II) mesoscale (radius
New insights on gypsum twinned crystals: mineralogical implications for natural gypsum deposits
Authors: Cotellucci Andrea , Otálora Fermín , Canals Àngels , Criado-Reyes Joaquín , Pellegrino Luca , Bruno Marco , Aquilano Dino , Garcia-Ruiz Juan Manuel , Dela Pierre Francesco , Pastero Linda
Published: March 2024

Identifying the impurities that promote the selection of specific twin laws of gypsum has relevant implications for the geological studies aimed at interpreting the gypsum depositional environments both in ancient and modern deposits, and overall, on Mars surface, where “swallowtail” gypsum twin habit has been recently observed. However, because of the limited knowledge of morphological, crystallographic, and optical characteristics of the five twin laws of gypsum, relatively little has been done to understand which impurities exert a critical role in the selection of different twin laws and how this may impact our awareness about their occurrence in nature. Typically, the 100-contact twin law has been the only twin law of gypsum known so far in nature. However, some sedimentological-stratigraphic studies suggested this might not be the only widespread one. In this work, we firstly provide a geometric-crystallographic background of the five twin laws of gypsum, allowing researchers to recognize the twin laws only by the measurement of i) their re-entrant angle value and ii) the extinction angle formed between the two individuals using crossed polarizers in optical microscopy. Moreover, we show specific crystal growth laboratory experiments designed to improve our understanding of different habits and twin laws of gypsum occurring with and without the addition of carbonate ions in solution. The main results suggest that the different orientation of primary fluid inclusions with respect to the twin plane, and the main elongation of the sub-crystals making the twin, are a useful tool to distinguish between 100 and -101 twin laws, whose geometry is otherwise very hard to distinguish, especially in rock samples. Moreover, gypsum twins obtained by crystal growth laboratory experiments are compared with those detected in natural environments and the occurrence of the -101 twin law is suggested occurring in evaporitic-sedimentary environments. These results provide new insights into the mineralogical implications of twinned gypsum crystals and their potential use as a tool for a deeper comprehension of the natural gypsum deposits.
Temporal Evolution of Isomer-Specific Reactivity in Dark-Aged β-Pinene Secondary Organic Aerosols
Authors: Resch Julian , Li Kangwei , Kalberer Markus
Published: March 2024

Collection of secondary organic aerosol (SOA) onto filters is often used in combination with LC-MS for detailed chemical characterization. Studies have shown that a large fraction of laboratory-generated SOA can be attributed to high molecular weight oligomeric compounds. Often there is a significant delay between sample collection and analysis (e.g., during automated filter collection) which may lead to changes in the chemical profile of the samples.In this study β-pinene SOA was generated by O3 and OH oxidation and collected onto filters, which were either extracted in a mixture of water and acetonitrile or left on the filter and stored at room temperature, to investigate changes in the overall chemical composition profile over time up to one month. The samples were analyzed by UHPLC-ESI-MS in negative polarity mode.An untargeted analysis led to several thousand detected compounds and principal component analysis indicated significantly different compositional changes between the samples stored on filters or as extracts. In order to understand these differences, further focus was put on previously identified carboxylic acids, dimer esters and other oligomers. The concentration of several hundred compounds in the monomer mass range increased in extracts over the 4-week time span, whereas the opposite was observed for samples stored on filters, where the concentration of a large number of monomers decreased. For dimers in samples stored on filters, a large number of compounds increased in concentration, while extracts show the opposite behavior.A possible explanation for these trends could be the decomposition through hydrolysis of dimer esters and other components in extracts and the formation of oligomers on filters. This indicates the continuous chemical aging of the SOA particles deposited and stored on filters. To test this hypothesis, we nebulized a solution of carboxylic acid standards in excess onto filters where β-pinene SOA was deposited and monitored the temporal evolution of dimer esters which have been reported to form from diaterpenylic acid and carboxylic acids. A stronger increase of the dimers (and a stronger decrease of the monomer precursor products) was observed for these “spiked” samples in comparison to the “non-spiked” SOA filter controls.This study not only highlights that the persistent changes observed on filters are due to previously overlooked on-filter reactions, which can lead to misinterpretation of the detailed chemical composition of samples collected on filters for offline analyses. These on-filter reactions also mimic particle phase non-oxidative aging of SOA over the entire lifetime of SOA particles in the atmosphere of days or weeks.
Elucidating the boundary-layer turbulence profiles observed by a radar wind profiler network in the Tibetan Plateau 
Authors: Guo Jianping , Meng Deli , Guo Xiaoran , Sun Yuping , Chen Tianmeng , Xu Hui
Published: March 2024

The planetary boundary layer (PBL) over the Tibetan Plateau (TP) imposes significant impact on regional and global climate, while its vertical structures and evolution features remain poorly understood. This study examines the evolution and possible mechanisms of daytime PBL turbulence profiles for cloud- and clear-sky conditions by using one-year observations from the radar wind profiler (RWP) network deployed over the TP, in combination with the measurements from the automatic weather station (AWS), millimeter-wave cloud radar (MMCR). The results show that the turbulence dissipation rate (e) are stronger and PBL height is higher in the norther part of TP (NTP), compared with those in the southern part of TP (STP). The presence of clouds inhibits turbulence transport within the PBL over the NTP, while the opposite effect was found over STP. Analysis of surface-air temperature difference  and wind shear data shows that both the thermal and dynamical effects strengthen the turbulence within PBL, and the thermodynamic effect is more important over STP than the NTP. The probability of PBL-cloud coupling is higher over the STP, and the cloud is found to enhance the PBL turbulence due to the strong wind shear, even although clouds can reduce the PBL height through radiative cooling effect. The findings help fill our knowledge gap in the PBL turbulence profiles throughout the whole TP, and highlight the significant role of the interaction between PBL turbulence and cloud in affecting the development of PBL turbulence over the whole TP.