bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Physical Flood Risk in the face of Climate Change: A Case Study for South Korea and South-Eastern China
Authors: Park Eunbeen , Jo Hyun-Woo , Son Jiwon , Kraxner Florian , Lee Woo-Kyun
Published: March 2024

The impact of climate change and extreme weather events, such as heatwaves and heavy rainfall, poses a severe environmental crisis, affecting both natural and socioeconomic systems, including governments and businesses. Responding to this, the Task Force on Climate-related Financial Disclosures (TCFD) emphasizes the need for organizations to quantitatively announce their physical risks and opportunities under climate change, highlighting proactive management of their risks.With its seasonal concentrated rainfall and topographical influences, East Asia faces escalating vulnerabilities to droughts and floods. Collaborative disaster response efforts at governmental and corporate levels are crucial. This study focused on the data availability in South Korea and China's southeastern region to develop flood risk models to support reporting by the TCFD.For South Korea, a model was developed by using time-series flood traces from 2006 to 2018 as training data, incorporating monthly maximum consecutive 5-day precipitation, topography, soil, and land cover maps into a random forest model. In China, a model was developed by combining monthly maximum consecutive 5-day precipitation and topographic information. Results highlight flood risks, particularly in South Korea's low-lying agricultural areas and southeastern China's lowland and coastal regions. Both countries experience increased flood risk under SSP1-2.6 and SSP5-8.5 scenarios from 2030s to 2050s, corresponding to rising future maximum rainfall.Given the tendency for floods to persist in previously affected areas, disaster preparedness through predictive measures becomes imperative, shifting the focus from post-disaster recovery to proactive disaster prevention. Additionally, guidelines for government and corporate-level utilization of available data and establishing action priorities in the event of a disaster are necessary.
Snow Distribution  Evaluation in High Mountain Asia: Observations and Modeling
Authors: Li Guang , Yu Hongxiang , Huang Ning
Published: March 2024

Snow in mountainous areas changes fast in space and time, resulting in strong spatial and temporal heterogeneity, which highly impacts the radiation balance and hydrological cycle. However, gaps still exist between observations and modeling due to serval issues. One issue is the absence of wind drifting and blowing snow (WDBS) processes in most mesoscale atmospheric models. A newly developed WDBS-coupled atmospheric model, CRYOWRF, was used to evaluate the snow distribution in the Tarim area and Namco area, to assess the impact of WDBS and its sublimation on the snow distribution. Field observations were also carried out to validate the modeling, which showed good agreement.  A highly temporal heterogeneity pattern is shown in High Mountain Asia due to the strong blowing snow sublimation. Our works prove that CRYOWRF has a good performance in High Mountain Asia.
Air Quality Assessment: Analyzing PM Distribution and Calibrating Low-Cost Sensors for Precise Measurements in Indoor and Outdoor Environments
Authors: Rubal Rubal , Ambekar Anirudha , Guttikunda Sarath K. , Thajudeen Thaseem
Published: March 2024

Air pollution is one of the leading causes of premature death across the world. To gain valuable insights into ambient fine particulate matter (PM) concentrations, a combination of regulatory monitoring networks, satellite retrievals of air-quality-related substances, and air quality models are typically employed. Studies reveal persistent exceedance of World Health Organization and national standards, particularly in developing nations. It is crucial to recognize that numerous regions in Asia and Africa still need proper monitoring systems to understand the emission sources and concentrations. A major obstacle to better spatiotemporal monitoring is the high cost involved in setting up the monitors.This research investigates the distribution and proportion of PM1, PM2.5, and PM10 in an educational campus using low-cost sensors (PMS5003, PMS 7003, Winsen ZH 06, SPS 30, Honeywell). A comparative analysis was conducted to evaluate the performance of these sensors against the TSI DRX DustTrak 8533 and calibrated with a beta attenuation monitor (BAM). Additionally, to enhance the accuracy and reliability of LCS measurements, the calibration through various regression and machine-learning (ML) techniques was explored under diverse environmental conditions. In the absence of calibration, the PM2.5 correlation (R2) between LCS and DustTrak is 0.62 to 0.73, indicating a moderate to strong relationship. However, compared to BAM, LCS correlation decreases (0.20 to 0.26), suggesting a weaker association. Utilizing ML with meteorological variables improves R2 values to 0.82 to 0.96 for DustTrak and 0.40 to 0.56 for BAM, with lower mean absolute and root mean square errors. The time-series results demonstrated typical seasonal patterns of winter highs and summer/monsoon lows. We also explored the PM concentrations in the kitchen and common dining facility using a combination of validated low-cost PM sensors (LCS) and DustTrak 8433. It is found that the prolonged cooking durations involved in high-heat cooking methods like stir-frying and deep-frying resulted in a rise in PM2.5, causing a higher exposure to PM. Overall, the findings of the study have provided valuable insights into the dynamics of PM2.5 emissions, the impact of cooking activities, effect of chimney and the importance of ventilation to reduce exposure to PM and implementing mitigation strategies to improve indoor air quality and protect human health.
Evaluating Boreal Wetland Methane Emissions in Fennoscandia using MAGIC2021 airborne measurements and Atmospheric Modelling
Authors: Langot Félix , Crevoisier Cyril , Lauvaux Thomas , Abdallah Charbel , Berchet Antoine , Gottschaldt Klaus-Dirk , Fiehn Alina , Pernin Jérôme , Guedj Axel , Ponthieu Thomas , Roiger Anke , Wittig Sophie , Saunois Marielle , Lin Xin
Published: March 2024

Boreal wetlands are components of the terrestrial carbon cycle, acting as significant natural sources of methane (CH4) in circumpolar regions. With accelerated Arctic warming, emissions from these ecosystems become hard to predict with high uncertainties on future hydrological regimes, wetland/permafrost extent, and organic matter decomposition rates, subsequently affecting CH4 emissions. Validation of accurate quantification methods for these emissions is therefore pivotal in order to better understand and manage potential climate feedbacks.In this context, the MAGIC2021 international large-scale field campaign's airborne measurements provide key empirical data to assess CH4 emissions from boreal wetlands in Fennoscandia. Led by CNRS and CNES, the campaign took place in August 2021 and involved 70 scientists from 14 international research teams. More than twenty instruments were deployed, onboard research aircraft (in-situ and lidars), as well as on stratospheric balloons (AirCores) and on the ground (EM27/SUN). In particular, obtaining CH4 concentrations from aircraft flights within the boundary layer allowed to directly capture the signatures of wetland emissions, offering a robust dataset for model validation.Our study employs two Lagrangian models, FLEXPART driven by ERA5 data and WRF-LPDM, to estimate wetland CH4 fluxes from these measurements. The use of these distinct Lagrangian approaches allows for cross-validation of results, enhancing the reliability of our findings. The derived fluxes are compared with outputs from two bottom-up emission models, WetCHARTs and JSBACH-HIMMELI, which simulate wetland CH4 dynamics at different scales and resolutions. This comparative analysis not only benchmarks the performance of these models against observational data but also sheds light on discrepancies in modelled bottom-up fluxes that can guide future improvements.Contributions of this study to the session include:A high resolution assessment of boreal wetland CH4 emissions and atmospheric distribution, using state-of-the-art airborne observational techniques.
Integration of multiple Lagrangian modelling frameworks to validate and corroborate CH4 flux estimates.
A critical evaluation of bottom-up models WetCHARTs and JSBACH-HIMMELI against empirical data, advancing our understanding of model uncertainties and informing on possible enhancements in wetland CH4 emission.
This research aims to further improve our understanding of methane emission processes from boreal wetlands, which helps improve predictions about these important ecosystems. The outcomes contribute to a more accurate global methane budget and underscore the importance of synergistic observational and modelling strategies in environmental science.
Spatially distributed streamflow buffering by glaciers during recent droughts in Switzerland
Authors: Buri Pascal , McCarthy Michael , Fatichi Simone , Brun Philipp , Karger Dirk , Chen Liangzhi , Zappa Massimiliano , Miles Evan S. , Shaw Thomas E. , Pellicciotti Francesca
Published: March 2024

During dry and hot years in the Swiss Alps, melt water from glaciers can moderate streamflow deficits caused by reduced precipitation and enhanced evapotranspiration rates. However, little is known about how glacier melt water contribution to streamflow varies sub-seasonally and in space, especially further downstream from glacierized catchments, where additional streamflow contributions are modulated primarily by rainfall and the biosphere (vegetation, soils).We study distributed catchment hydrology in Switzerland using a land surface model that constrains energy and mass fluxes using advanced physical representations of both cryospheric and biospheric processes at a 250 m spatial resolution. We simulate catchment runoff in Switzerland during the past 6 years, including two recent severe drought years (2018 and 2022), characterized by particularly warm summers and reduced precipitation. The model is forced with hourly observed meteorological data based on the weather station network SwissMetNet and the precipitation product RhiresD, and uses state-of-the-art land cover, soil characteristics, glacier area and debris thickness as initial conditions.The spatially explicit simulations allow, when temporally aggregated, to trace upstream contributions of individual water balance components for any downstream point in the catchment. We use the model to quantify the amount and timing of glacier melt and how it affects downstream runoff composition, especially during drought conditions, along the river network. We do this across regions from the Swiss Alps’ headwaters to the lowlands in a spatially continuous way.When comparing runoff composition during moderate summer months to periods of drought conditions in the Swiss Alps, our simulations show both an increase in intensity and downstream propagation of ice melt contribution to total runoff. During extreme drought periods, ice melt makes up >70% of streamflow (~doubling the contributions during more moderate periods) in some of the Alps’ headwater regions (>1500 m a.s.l.), and still exceeds 10% of streamflow contribution downstream of the pre-alpine region.Quantifying the timing and amount of glacier melt contributions to downstream water resources under recent drought conditions improves our understanding of potential cryosphere-biosphere interactions and their impacts under future extreme scenarios, when cryospheric runoff contributions may be reduced or completely lost.
The impact of mixed-phase cloud processes on radiative fluxes over the Southern Ocean in a convection-permitting model
Authors: Smith Daniel , Renfrew Ian , van den Heuvel Floor , Lachlan-Cope Tom , Crawford Ian , Bower Keith , Flynn Mike
Published: March 2024

Atmospheric and climate models have large biases in their short and long wave radiative fluxes over the Southern Ocean, leading to significant errors in their sea surface temperature, sea ice and large scale circulation. The primary cause for these biases is the representation of low-level clouds, both at the macro- and micro-scale. We assess the performance of a convection-permitting configuration of the Met Office Unified Model (MetUM) over the Southern Ocean using satellite and aircraft observations from the 2023 special observing period of the Southern Ocean Clouds (SOC) field experiment. We focus on the model’s sensitivity to the microphysics schemes. Firstly, the impact of ice nucleating particles (INP) parametrizations via sensitivity experiments using different temperature dependent INP distributions: (i) from Cooper (1986); (ii) as derived for the east Antarctic coast; and (iii) a new distribution derived from observations from the west Antarctic Peninsula during the SOC experiment. Secondly, we examine the impact of the parameterized overlap between ice and water within a grid box (the mixed-phase overlap factor), which modifies mixed-phase process rates, for example the Wegener–Bergeron–Findeisen process and riming. Reducing the INP concentration to values observed over the Southern Ocean results in top of the atmosphere (TOA) radiative fluxes closer to observations. The lower INP concentrations result in lower ice water content and higher liquid water content, leading to brighter and more widespread cloud; this increases the albedo, resulting in a more accurate simulation of the TOA radiation. Equally, a large sensitivity in the top of the atmosphere fluxes is seen when changing the mixed-phase overlap factor. Decreasing (increasing) the mixed-phase overlap factor results in less (more) ice and more (less) liquid reducing the TOA fluxes. Decreasing the mixed-phase overlap factor results in TOA fluxes closer to the satellite observations. In summary, simulations using INP concentrations suitable for the Southern Ocean result in simulations closer to observed but other parametrizations in the microphysics scheme are equally important for accurate simulations of radiative fluxes.
AWSoM solar wind model with charge states and ion temperatures
Authors: van der Holst Bart , Landi Enrico , Gombosi Tamas
Published: March 2024

We present a multi-ion generalization of the AWSoM model, a 3D global magnetohydrodynamic (MHD) solar corona and inner heliosphere model with incompressible turbulence. The AWSoM model with charge states is further extended to include temperatures for the various heavy ion species. The coronal heating is addressed via outward propagating low-frequency Alfven waves that are partially reflected by Alfven speed gradients. The nonlinear interaction of these counter-propagating waves results in turbulent energy cascade. To apportion the cascaded turbulent energies to the electron and ion temperatures, we employ the results of the theories of linear wave damping and nonlinear stochastic heating. This heat partitioning results in a mass proportional heating among ions.
Tectonic drivers of the scaling dinosaurian fossil record
Authors: Spiridonov Andrej , Lovejoy Shaun , Balakauskas Lauras , Daumantas Liudas
Published: March 2024

The fossil record is the only direct source of information of the evolution, ecology, and biogeography of non-avian dinosaurs. The taphonomy is the science of the study of transition of biological information in to the stratigraphical record. The stratigraphical record is characterized by multiscale spatial and temporal structure. The largest scale structures are often called “megabiases”. Here we study the structure of megabiases of the dinosaurian fossil record from the Paleobiology Database in time as well as in space. We found a strong tendency of dinosaur occurrences to cluster at tectonic plate boundaries. Moreover, there are systemic temporal differences in the degree of this outward distribution of occurrences which are related to the sea level and the degree of tectonic fragmentation. Finally, we used spatial distributional patterns in simulating occurrences, and determined the effects of such inhomogeneities on the accuracy of determination of bioprovinces using newly developed R package ‘HespDiv’ for contiguous spatial cluster analysis.The study was supported by the grant by S-MIP-21-9 “The role of spatial structuring in major transitions in macroevolution”.
Transition towards low-carbon emissions: A Comparative Analysis between Western Macedonia (Greece) and Rhenish (Germany)
Authors: Tagaris Efthimios , Tranoulidis Apostolos , Sotiropoulou Rafaella-Eleni P. , Bithas Kostas
Published: March 2024

The transition away from fossil fuels involves management challenges since the socioeconomic prosperity of the affected areas should be assured. This study assesses the mechanisms, and the future planning of two European regions - Rhenish in Germany, and Western Macedonia in Greece – currently under decarbonization. The assessment is grounded in the application of the five EU - recommended tools, i.e., the governance tools, the sustainable employment and welfare support toolkit, the environmental rehabilitation and repurposing toolkit, the financial toolkit and the technology options toolkit. Rhenish region is targeting for lignite phase-out by 2038 whilst Western Macedonia has set a target for the completion of the transition away from lignite by 2028. The analysis carried out here has shown that both regions have adopted comprehensive strategic plans, delineated transition roadmaps, and established economic models. In particular, both regions have similar governance structures in place and have adopted comparable action plans for sustainable employment and welfare support. However, Western Macedonia faces some implementation challenges and delays in the sector of Reclamation and repurposing efforts. The financial structure of both regions is similar, with the EU and the state being the primary funding sources. Both regions are primarily considering technology options that prioritize the repurposing of power plants, the reduction of carbon emissions in energy-intensive industries, the utilization of hydrogen technologies, and non-electric carbon applications. The findings of this work will contribute to the development of viable strategies for coal transition in diverse national contexts. By thoroughly evaluating the experiences of these locations, this work aims to inform policymakers and stakeholders about effective approaches to navigate the challenges associated with decarbonization while ensuring sustained prosperity in affected areas.
SMOS after 14 years in orbit:Status, Achievements, and future plans
Authors: Kerr Yann
Published: March 2024

The ESA (European Space Agency) led SMOS (Soil Moisture and Ocean Salinity) mission, operating since November 2009, is the first satellite dedicated to measuring surface soil moisture and ocean salinity. It has been now in operation continuously for more than 14 years, delivering a wealth of new measurements including the first time ever global, frequent, quantitative and absolute measurements of soil moisture and ocean salinity. From these measurements a large number of science and applied products have emerged ranging from strong wing or thin sea ice thickness to root zone soil moisture or biomass but also fire or flood risks prediction, snow density or freeze thaw to name but a few. Operational users (such as numerical weather prediction) have also emerged. To obtain such results several challenges had to be addressed and overcome but results show the uniqueness of L band radiometry for some crucial water cycle measurements.Currently, using the long term data set and developing approaches to extend it in time, climate trends can start to be considered as well as teleconnections and SMOS is contributing to a large number of ECV (Essential Climate Variables) / CCI (Climate Change Initiative). At the time of writing SMOS is in very good condition and can last for a few more years, extending the length of the data sets but will not last forever. Consequently the team is both investing time in new or improved science and application products but also on potential follow on mission which would be very much similar to SMOS (or SMAP) but with a significantly improved spatial resolution.The presentation will give an overview of the most striking new results as well as future plans.
Co-benefit valuation of urban and peri-urban nature in high resolution on continental scale
Authors: Löwe Roland , Viti Martina , Arnbjerg-Nielsen Karsten , Ladenburg Jacob
Published: March 2024

Space is a highly valued asset in cities. This is a key reason why nature-based solutions (NBS) for water management are often perceived to be more expensive than traditional greysolutions. Promoting NBS implementation requires methods for quantifying their non-market benefits that are widely accepted and easy-to-apply in early planning and brainstorming stages.In this work, we develop a predictive metamodel for the total economic value of urban and peri-urban nature, based on 114 stated-preference valuation studies of nature in (peri-)urban areas and openly available geographic data from across the world. The dataset covers the entire range of NBS types with sizes from 0.5 to 900.000 ha. We employ a mixed-effects modelling approach and use a cross-validation procedure to determine which factors affect the willingness to pay for (peri-)urban nature. We consider the predictive performance of 8.4 million model permutations that consider different combinations of site properties and topographic and socio-economic characteristics of the surroundings as input.We find that the total economic value is determined by the size of the nature areas and population densities in their surroundings. There is clear evidence for substitution effects where available nature areas reduce the willingness to pay for new nature. Beyond the dependency on area, there is little evidence for making distinctions between nature types. Economic values do depend on the average income at a site, but these variations are entirely captured by purchase power corrections. Our value estimates are aligned with related literature and range between 150 and 400,000 USD/ha/year. We have implemented our metamodel into a freely available Python program, which generates maps of the predicted values for any location in Europe in a spatial resolution of 100m.
Impact perception as driver for extreme event definition, identification and monitoring
Authors: Lima Alencar Pedro Henrique , Ford Trenton Wayne , Paton Eva Nora
Published: March 2024

The current approach to defining (flash) droughts in climate and hydrology typically relies on standardized indexes like SPI, SMI, and SPEI, combined with specific thresholds to determine the onset and conclusion of these events. However, this methodology often overlooks a crucial aspect – the impacts that communities experience during these events, such as plant mortality, well drying, or heat stress. We propose a novel framework that integrates the community's perception of extreme events, considering both the impact and risk tolerance of these communities. Our approach involves actively engaging with communities and stakeholders to understand their perception of extreme events, their associated impacts, and their levels of resilience and risk acceptance. By leveraging hydrological and crop models alongside historical and projected climate data, we can analyse conditions associated with specific impacts and the severity of these impacts for each community or user group. Additionally, we can develop local definitions of droughts and other related extreme events that align more closely with community perceptions and relevant impacts. This tailored approach aims to enhance communication and resilience within these communities. We tested this new framework in the farming communities of Illinois (USA), Brandenburg (Germany) and Ceará (Brazil), where we identified varying perceptions of drought impacts. Using these insights, we formulated distinct definitions of flash droughts for different regions, considering local climate conditions and community perspectives. This approach resulted in improved event identification and definition, facilitating more effective communication and empowering community actions. 
Short-term effects of ultrafine particles on mortality
Authors: N. Dos Santos Vanessa ,   RI-URBANS contributors
Published: March 2024

Particulate matter (PM) was estimated to cause 4.2 million deaths worldwide in 2019; however, evidence on which components are responsible for its effects on mortality remains inconsistent. Ultrafine particles (UFP, < 100 nm in diameter), the smallest fractions of PM, have the potential to individually harm health as they are small enough to reach multiple organs of the human body in contrast to larger fractions. To efficiently decrease the effects of PM on health, it is crucial to understand which PM components pose the highest health risks and to tackle them in future regulations.In this study, we aim to quantify the short-term effects of PM properties and components on mortality from natural, cardiovascular and respiratory causes. We associated daily concentrations of different PM properties and components (including UFP size fractions, UFP sources, black carbon, lung deposition surface area, PM2.5 (10 nm) modes showed similar results, indicating that both UFP and Ntotal (>10 nm) could potentially be used as indicators for the health effects of the smallest aerosol size fractions, dominant in number. The health effects of the UFP mode remained statistically significant for natural mortality after adjusting for PM2.5. Similarly, the effects of the UFP mode remained significant for natural and cardiovascular mortality after individually adjusting for PM10 and NO2.Our preliminary results suggest that the smallest aerosol particle size fractions (e.g., UFP) may independently impact health.
Examining Patterns of Temperature and Precipitation Biases in a Dynamic Downscaling Process across Europe
Authors: Sotiropoulou Rafaella - Eleni , Stergiou Ioannis , Tagaris Efthimios
Published: March 2024

The Weather Research and Forecasting (WRFv4.0 ARW) mesoscale meteorological model dynamically downscales data from the NASA Goddard Institute for Space Studies (GISS) GCM ModelE2 atmospheric general circulation model (GCM) CMIP5 version (Model E2-R) over Europe to replicate the observed bias and temporal variability and the previously observed impact of climate change on critical meteorological parameters. Given that RCM outputs are still susceptible to climate model errors from the RCM's structure and the driving GCM/ESM's initial and boundary conditions, examining a model's ability to replicate changes in climatic factors over the last several decades is an intriguing task. This activity identifies systematic biases and examines their sources. WRFv4.0 ARW is single-nested with 0.75°–0.25° grid resolutions. The past and current periods are represented by two 30-year datasets, 1951–1980 and 1981–2010. Model biases for mean temperature, mean precipitation, the number of days with temperatures exceeding 25 °C, and days with precipitation surpassing 5 mm (following WMO guidelines) were compared against E-OBS observations at a 0.25° spatial resolution. The analysis revealed consistent underprediction of mean temperature changes across all subregions, indicating a colder climatology assessment, especially during winter in southern and eastern subregions. Most subregions have the strongest bias in winter. The southern and eastern subregions show the largest bias due to land-atmosphere interactions. Conversely, spring or fall simulate the lowest biases. The lower snow cover during these seasons counters the overestimation of surface albedo in winter, and the radiation scheme has a gentler effect than in summer. In terms of days with a mean temperature above 25 °C, Southern Europe experiences an increased number of them. Model biases in mean precipitation displayed a general negative trend across subregions, a known issue in WRF simulations influenced by regional weather patterns that do not show a geographically regular trend. Over the two time slices, northwestern Europe had more days per month with mean daily precipitation above 5 mm than the middle and southern regions. Model simulated bias is quite small everywhere, demonstrating competence in predicting changes beyond the threshold. Model seasonal findings were always comparable to observations, despite minor regional differences. This study underscores the importance and need for more observations, particularly from southern Europe, for more credible evaluation studies.
Regularization scheme in ALTIUS retrieval algorithms
Authors: Berthelot Antonin , Baker Noel , Demoulin Philippe , Franssens Ghislain , Fussen Didier , Gramme Pierre , Mateshvili Nina , Pieroux Didier , Sotiriadis Sotiris , Dekemper Emmanuel
Published: March 2024

ALTIUS (Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere) is an atmospheric limb mission being implemented in ESA's Earth Watch programme and planned for launch in 2026.The instrument consists of three imagers: UV (250-355 nm), VIS (440-675 nm) and NIR (600-1040 nm) channels. Each channel is able to take a snapshot of the scene independently of the other two channels, at a desired wavelength and with the requested acquisition time. The agility of ALTIUS allows for series of high vertical resolution observations at wavelengths carefully chosen to retrieve the vertical profiles of species of interest.ALTIUS will perform measurements in different geometries to maximize global coverage: observing limb-scattered solar light in the dayside, solar occultations at the terminator, and stellar, lunar, and planetary occultations in the nightside. The primary objective of the mission is to measure high-resolution stratospheric ozone concentration profiles. Secondary objectives are the retrieval of mesospheric ozone, stratospheric aerosols particle density and extinction coefficient, NO2, NO3, BrO, OClO, water vapor and temperature profiles.The Level-2 retrievals use a Levenberg-Marquardt algorithm coupled to a Tikhonov regularization scheme to limit noise amplification during the inversion process. The type and strength of regularization has a direct effect on the retrieved profile vertical resolution. Therefore, a trade-off has to be found between noise removal amplitude and vertical resolution. A study on the different regularization constraint types is performed and the regularization strength is determined using the retrieval noise error in stellar occultation mode for O3 and NO2 density and aerosol extinction retrievals. The ability of Tikhonov regularization to remove the effects of scintillation on the retrieved profiles is discussed. Moreover, a re-processing of GOMOS data is performed to test the validity of our approach.
Quantitative CT scan analysis: an innovative tool for interpreting ice-contact sediments from overdeepened basins of the northern Alpine foreland
Authors: Schuster Bennet , Schaller Sebastian , Gegg Lukas , Buechi Marius W. , Anselmetti Flavio S. , Preusser Frank
Published: March 2024

Overdeepened basins are shaped and filled by the interplay of erosion and deposition during one or more glacial-interglacial cycles. Understanding and correlating the sedimentary infill of overdeepened systems is a key to understanding glacial dynamics in terms of the timing, extent, and character of Quaternary glaciations. Therefore, numerous overdeepened structures in the northern Alpine foreland have been explored by research drilling in recent years, resulting in a large collection of sediment cores of excellent quality, providing a unique opportunity to gain insight into these structures. Exploration of these basins shows that a depositional sequence in the sedimentary record of a glacial overdeepening typically begins with the subglacial deposition of coarse-grained units (diamicts and gravels), reflecting complex ice-bed-interactions during the transition from erosion to deposition. The identification and interpretation of these potential ice-contact sediments is crucial for understanding the glacial sedimentary sequences.In this study, we use X-ray computed tomography (CT) scanning to identify and quantify sedimentological features and systematically characterise a wide range of potential ice-contact sediments from different levels within the sedimentary record of several overdeepened basins in the northern Alpine foreland. CT scanning provides a powerful tool for the detailed analysis of sedimentary drill cores, particularly in these glacial sediments, where such examinations have never been carried out on a large scale. This study aims to establish a CT analysis workflow and a database of characteristics of ice-contact sediments. This will contribute to the controversial discussion of the relevant processes that form ice-contact sediments and improve our ability to identify ice-contact sediments and their genesis in overdeepened basins.
Trace Modelling: A Quantitative Approach to the Interpretation of Ground Penetrating Radar Profiles
Authors: Schettino Antonio , Ghezzi Annalisa , Tassi Luca
Published: March 2024

Classical analysis of radar profiles generally relies on a visual inspection and interpretation of profiles and sometimes on inverse modelling of the acquired data. Both methods suffer severe limitations due to the antenna resolution, thereby preventing the identification of tiny structures, especially in forensic applications. Here we describe a forward modelling technique, which allows to reproduce individual traces (A-scans) of radar profiles through superposition of Ricker wavelets. The method allows to detect ultra-thin layers, well beyond the Ricker and Rayleigh vertical resolution of GPR antennas. This approach starts from an estimation of the instrumental uncertainty of common monostatic antennas and takes into account of the frequency-dependent attenuation, which causes spectral shift of the dominant frequency acquired by the receiver antenna. The forward modelling procedure loads a single trace from a radar profile and allows to build a synthetic A-scan by fitting a sequence of Ricker wavelets with user-defined amplitude, polarity, and arrival time to the acquired trace. The resulting synthetic trace can be used to create a reflectivity diagram that plots reflection amplitudes and polarities versus depth. Often a reflectivity diagram shows intervals bounded by reflectors of opposite polarity, associated with layers having higher or lower velocity than the surrounding material, respectively. These intervals may result from very subtle features that represent interesting survey targets, for example buried bones, small cracks, thin lens of liquid contaminants, etc. and could be confused with individual reflectors through the simple visual inspection of a radar profile. Our quantitative approach can be used in several applications of GPR methods, especially in forensic, paleontological, civil engineering, heritage protection, and soil stratigraphy applications.
Testing the penitente hypothesis on Europa via photometric roughness
Authors: Mishra Ishan , Buratti Bonnie
Published: March 2024

Spiked, icy features, akin to the ‘penitentes’ on Earth [1], have been found on other airless bodies in the solar system as well, such as the 'bladed terrains' of Pluto [2] and the 'spires' of Callisto [3]. These features, thought to be formed due to sublimation erosion, are present in young, crater-less regions and hence represent an active response of the surfaces of these bodies to changing seasonal and climatic conditions. Interestingly, penitente formation has also been hypothesized on Europa [4], albeit the feasibility of that process on Europa has been questioned [5]. A fundamental limitation of testing this hypothesis for Europa is the lack of images at the resolution of the proposed penitente features (~ 15 m), unlike the images of the bladed terrains of Pluto from New Horizons and spires of Callisto from Galileo which clearly show these features. Photometric roughness models peer below the resolution limit of the camera to offer a glimpse of any surface roughness that is in the geometric optics limit.  Our roughness model [6], which has been successfully fit to a range of planetary bodies [7,8], will enable us to probe the surface roughness of Europa and test the penitente-hypothesis. We are locating Galileo images from the equatorial regions of Europa (within an equatorial zone restricted to ±24° where they are hypothesized to exist) and extracting scans of specific intensity (I/F) with backplanes of geometric coordinates. We will fit these I/F curves with our photometric model to derive roughness values, which will be compared to the proposed roughness of ~ 60° [4]. This predicted roughness is very high, so its effect on the light reflected from the surface should be easily detectable. To get a useful point of comparison for the roughness values we obtain for Europa, we will also perform a roughness analysis of the spires of Callisto, which are in a similar size regime of ~ 100 m. [1] Claudin, P. et al. (2015), Phys. Rev. E, 92(3), 033015; [2] Moore, J., et al. 2018, Icarus 300, 129-144, [3] Howard, A. D., & Moore, J. M. (2008). GRL, 35(3), L03203 [4] Hobley, D.E.J. et al. (2018). Nat. Geosci., 11(12), 901-904. [5] Hand, K.P. et al. ( 2020). Nat. Geosci., 13(1), 17-19. [6] Buratti, B. J., & J. Veverka (1985), Icarus 64, 320-328; [7] Buratti, B. J. et al. (2006). Planet. & Space Sci. 54, 1498-1509 [8] Lee, J. et al.  (2010), Icarus 206, 623-630.
Expert-based global database of sand dams dimensions and distribution across drylands
Authors: Eisma Jessica , Piemontese Luigi , Castelli Giulio , Quinn Ruth , Mpofu Bongani , Graber Neufeld Doug , Ryan Cate , Ritchie Hannah , Villani Lorenzo , Bresci Elena
Published: March 2024

Sand dams are water harvesting structures built across ephemeral sandy rivers to increase water supply in drylands. Despite their effectiveness in reducing water scarcity for local communities and their recent traction in research and development, information on their distribution and characteristics are sporadic and largely unreported. This gap represents a major barrier for understanding the large-scale potential of such a Nature-based Solution for drylands and planning for new infrastructure. This paper presents a global database of sand dam locations and dimensions developed within a collaboration between research and development experts on the topic. We collected sand dam information on location from several sources, ranging from research reports to databases provided by practitioners. We then reviewed and enriched them based on visual inspection from Google Earth images. The georeferenced information provided by the database can support research development on the effectiveness of sand dams and support practitioners with science-based criteria for sand dam development across global drylands.
Modulation of surface and sub-surface circulation in the Bay of Bengal by the passage of tropical cyclone Jawad: coupled ocean-atmosphere feedback 
Authors: Chakraborty Tapajyoti , Pattnaik Sandeep , Joseph Sudheer
Published: March 2024

The Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) model has been employed to simulate the anomalous post-monsoon tropical cyclone (TC) Jawad that originated over the Bay of Bengal (BoB) in December 2021. The atmospheric initial and boundary conditions (IC and BC) have been obtained from the Global Forecasting System (GFS) Analyses and Forecasts and two contrasting ocean IC and BCs, viz., HYCOM (experiment name GFS-HYCOM) and INCOIS (experiment name GFS-INCOIS), are implemented in two separate coupled experiments to evaluate the influence of TC Jawad on the surface and sub-surface characteristics of BoB. The track of the TC, including its recurvature, was well captured by both experiments with significant accuracy. A proper contrast in temperature between the two sides of the TC track was noted in the surface and sub-surface temperatures observed by two buoys, i.e., (1) BD11 (west of the TC track) and (2) BD13 (east of the TC track), and the simulated temperatures were validated with these observations. Contrary to the usual scenario, the higher sub-surface warming on the eastern side of the TC track was captured by GFS-HYCOM, but with a significant overestimation. The lower temperature on the western side of the TC track can be attributed to the weak upwelling associated with the cyclonic circulation caused by the interaction of the TC with the southward coastal currents. An unusually higher downwelling on the eastern side of the TC track was observed in the vertical distribution of the temperature across the longitudes, which suggested the existence of a strong clockwise circulation near the location of BD13. GFS-HYCOM, which simulated a higher current magnitude in the sub-surface than GFS-INCOIS on the eastern side of the TC track, captured the circulation near BD13 more rigorously. From further analysis, it was inferred that the interaction of the cyclonic wind flow of TC Jawad (westerly) near the surface with the easterly flow caused the generation of the clockwise circulation over the ocean surface on the eastern side of the TC track, leading to intense downwelling and warming of the sub-surface temperature. This scenario was further corroborated by the simulated Ekman transport and higher convective activity in the eastern quadrants of the TC. The present study not only emphasizes the capability of the coupled ocean-atmosphere models to simulate TCs but also highlights the necessity of investigating the air-sea interaction processes and their responses to the passage of an anomalous TC like Jawad.
Quantifying the buffer storage effects of a plant
Authors: Pathak Vinod S , Srinivasan Venkatraman
Published: March 2024

Plant water storage (PWS), which protects plants from water stress during severe droughts, also regulates a number of aspects of the spatio-temporal dynamics of water transport in the soil-plant system. Overestimation or underestimation of transpiration is possible if we equate the amount of water that is absorbed by the roots to the total sap flux that is transpired to the atmosphere through the leaves. Experiments suggest that shoot/stem storage fluxes contribute to 2-15% of the total sap flux in trees. Most of the above ground storage fluxes contributing to the total sap flux in trees come from the middle segment of the plant stem. While experiments have been done to measure shoot storage contribution to sap flux, root storage contributions to sap flux still remains unknown. Experiments have also shown that root biomass contributes up to 40% of the total tree biomass which is significant, itbecomes important to quantify root storage fluxes in the trees. There are models available estimating water storage fluxes within the trees. Nevertheless, these models do not quantify the water storage fluxes and its contribution to the sap flux explicitly within the roots.
Rupture Dynamics and Characteristics During Earthquake Cycles on Nonplanar Faults with Strongly Rate-Weakening Friction
Authors: Tal Yuval
Published: March 2024

Natural faults exhibit complex geometry. In this study, we model cycles of earthquake ruptures on non-planar faults governed by a friction formulation that combines rate and state friction for low slip velocity and enhanced weakening friction in the form of flash heating for high slip velocity, both consistent with rock friction experiments. The numerical method allows non-matching meshes across the fault, continuously updates the fault geometry, and employs variable time steps with quasi-static and fully dynamic time integration schemes during slow and fast deformation stages, respectively. To prevent the development of large stresses on the fault, the model also accounts for fault wear and inelastic off-fault deformation. We investigate the effect of macro-scale roughness on the fault slip behavior and rupture dynamics in terms of event magnitude, stress drop, and rupture style and speed. We analyze the relationship between the fault geometry, stresses from the preceding earthquakes, and rupture characteristics.The simulation results show a significant increase in event variability with roughness levels, with both small partial ruptures and ruptures significantly more intense than those on planar faults. The planar faults host a sequence of earthquakes that rupture the entire fault, exhibiting similar magnitudes and stress drops. The substantial reduction in friction enables the ruptures to propagate under a low background shear-to-normal stress ratio as self-healing slip pulses, with a sub-Rayleigh rupture speed. Faults with low roughness levels generally show a similar pattern. Prior to some events, the stress ratio along the fault slightly increases, leading to ruptures with secondary slip pulses and larger magnitudes. As roughness increases, stresses become more heterogeneous, resulting in a more complex sequence of ruptures, some of which arrest at restraining bends with a low stress ratio. However, stress accumulation and slip deficit during these partial ruptures result in high stress ratios on the unruptured fault segments. These are eventually released by large events of crack-like ruptures with supershear propagation speed and stress drops and slip significantly larger than a typical event on a planar fault. Therefore, while fault roughness can cause rupture arrest, consistent with previous studies, it can also substantially increase earthquake magnitudes. This factor should be accounted for in earthquake hazard assessments.
GraphCast: Learning skillful medium-range global weather forecasting
Authors: Sanchez-Gonzalez Alvaro ,   GraphCast team from Google DeepMind
Published: March 2024

Global medium-range weather forecasting is critical to decision-making across many social and economic domains. Traditional numerical weather prediction uses increased compute resources to improve forecast accuracy but does not directly use historical weather data to improve the underlying model. In this talk we will be presenting GraphCast, a machine learning–based method trained directly from reanalysis data. It predicts hundreds of weather variables for the next 10 days at 0.25° resolution globally in under 1 minute. We compare GraphCast to the most accurate operational deterministic system (HRES) and show how its forecasts produce state of the art metrics, and support better severe event prediction, including tropical cyclone tracking, atmospheric rivers, and extreme temperatures. We also show how the approach can be extended to probabilistic forecasting to materialize similar improvements against ENS, a top operational ensemble forecast. These models are key advances in accurate and efficient weather forecasting and help realize the promise of machine learning for modeling complex dynamical systems.
Towards a unified description of the count rate – snow water equivalent relationship in cosmic-ray neutron sensing
Authors: Fersch Benjamin , Součková Markéta , Schattan Paul , Krebs Nora , Weimar Jannis , Jahn Carsten , Grosse Peter Martin , Schrön Martin
Published: March 2024

The observation of near-ground cosmogenic neutrons enables the monitoring of various water storage variations at the land surface at the field scale including soil moisture and the water content of snow layers. The parabolic neutron-count versus soil moisture function is quite uniform among different locations, and soil types and requires typically a one-time-only in situ reference observation. For the detection of snowpack water equivalent (SWE) variations by cosmic-ray neutron sensing such a uniform approach has so far not been developed. Therefore, the establishment of new cosmic-ray snow monitoring sites requires substantial in situ measurements for obtaining the local relationship of SWE amounts and neutron count rates. Observations suggest that the relationship is quite uniform for grass-vegetated locations which is different to what is found for stony ground.Within the framework of the research unit Cosmic Sense, we generated extensive in situ measurements of snow water equivalent and cosmogenic neutron count rates at various sites with differing elevations in the German and Austrian Alps. From these data, we investigate commonalities among the site conditions and if the varying patterns of the relationships can be reasonably explained by physical reasons and therefore be modeled with a unified approach.