bluuebunny/crossref_metadata_2025 huggingface dataset:
Future Atmospheric Rivers in Antarctica using CMIP6-IPSL model : intensity and impacts
Authors: Barthelemy Léonard , Codron Francis , Favier Vincent , Wille Jonathan
Published: March 2024

Atmospheric Rivers (AR) are extreme hydrological events that have strong impacts on the different components of the Antarctic ice sheet surface mass balance (SMB), through both snow accumulation and surface melt due to heating and rain. Their evolving characteristics are therefore important to understand for an accurate prediction of future SMB changes.We use here an ensemble of simulations of the mid-21st century climate using the IPSL-CM6 model. The future Antarctic ARs are identified using a detection algorithm adapted to the region, and taking into account in the detection threshold (based on moisture fluxes) the rising background moisture in a warmer climate. While a constant detection threshold leads to a continuous increase of the number of ARs detected, the use of this adaptative threshold leads instead to a relatively stable frequency of occurence, but with a larger penetration over Antarctica (+5% occurence over the continent). In addition, a wave number 3 component appears in the future change in frequency, as well as in AR-related snowfall.While the number of ARs does not change much, their intensity, as measured by the associated water vapor transport, increases in line with the Clausius-Clapeyron relation. Their different impacts on the SMB also become larger, with both increasing snowfall, and surface melt and rainfall in the coastal regions. The direct effect on the SMB is however dominated by the increase in snow accumulation.
The delineation of graphite deposits in Lower Austria using the Transient Electromagnetic method
Authors: Monsalve Martinez Jorge Luis , Aigner Lukas , Flores-Orozco Adrian , Moser Clemens , Högenauer Philipp , Römer Alexander
Published: March 2024

The European Commission classifies graphite as a critical raw material, given its importance in refractory and high-tech applications, including the production of lithium-ion batteries. Many of Austrias graphite deposits are situated in and around the so-called “Drosendorf-Deckensystem” in Lower Austria. As those sites have been extensively mined out in the near-surface and are heavily weathered, the current interest of the potential assessment primarily focuses on the spatial extent of the graphite deposits, with particular interest in the deep continuation of these graphite deposits. Geological cross-sections are a standard approach for understanding subsurface graphite distribution, relying on available structural, geochemical, and/or lithological data. However, such information is primarily derived from surface observations, limited to exposed surfaces or outcrops. Geophysical methods can play a crucial role in extending the interpretation of geological cross-sections both horizontally and vertically. Due to the high electrical conductivity of graphite, electromagnetic and electrical methods like the Transient Electromagnetic (TEM) and the Induced Polarization (IP) are commonly applied for exploration. The IP method complements traditional electrical resistivity methods by measuring not only subsurface conductivity but also variations in the electrical capacitive properties (polarization) at low frequencies. In this study, we explore the feasibility of integrating the interpretation of IP and TEM measurements. The latter is known for its cost-effective coverage of large areas with high resolution and depth of investigation, compared to other geophysical methods. For that purpose, multiple TEM soundings were acquired in a ca. 4 km long profile between Berging and Kochholz in Lower Austria, situated in the geological section called “Drosendorf-Deckensystem”. The inversion of TEM data revealed distinct high-conductivity anomalies (100 – 200 mS/m) at approximately 40 m depth, attributed to the presence of graphite. A parallel comparison with two 160 m – 250 m long Time-Domain IP profiles confirms the graphite presence, attributed by high conductivity and high polarization (σ’ > 200 mS/m, σ” > 20 mS/m). Integrating these results along a geological cross-section improved the delineation and understanding of graphite deposits at depth and their correlation with lithological features in Lower Austria. Furthermore, these findings confirm that acquiring physical property models related to TEM and IP surveys has the potential to enhance mineral exploration.This research work was co-financed by the Federal Ministry of education, science and research and supervised by the Federal Mining Authority of Austria within the framework of the VLG83 project (Raw Material research initiative).
Impact of clouds on the forest albedo measured at the Leipzig Canopy Crane - A pilot study
Authors: Wolf Kevin , Schäfer Michael , Shekhar Jha Sudhanshu , Weigelt Alexandra , Richter Ronny , Kühne Tom , Ehrlich André , Jäkel Evelyn , Wendisch Manfred
Published: March 2024

Albedo, defined as the ratio between reflected radiation and total incoming radiation, is a key variable in the Earth radiative budget. In a fast changing climate with more frequent extreme events, such as droughts and excessive heat, vegetation is under constant stress. Such stress factors might modify the tree physiology, the reflectivity of individual leaves, and, eventually, the forest albedo as an entity. This might alter the local radiative budget and contribute to changes in the local climate, e.g., intensifying drought - a potential feedback loop. The understating of those effects might be further complicated by the occurrence of clouds. Therefore, this study presents spectral solar measurements of upward and downward irradiance that are used to determine the spectral albedo over a forest canopy. Since June 2021, ongoing measurements are performed on top of the Leipzig Canopy Crane located in the Leipzig floodplain forest. The measurements are separated for illumination geometries, i.e., the solar zenith angle, as well as for different cloud conditions. The interpretation of the measurements is aided and validated by coupled radiative transfer simulations using the library for radiative transfer model (libRadtran) and the Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE2.0) model. Both models allow for simulations in the visible, near- and far-infrared wavelength range. By that, the impact of clouds on the spectral and broad band albedo, as well as the net radiative budget can be investigated. First simulations revealed that the presence of clouds enhance the spectral forest albedo. The magnitude of the effect is controlled by the cloud optical thickness, i.e., the ratio of direct and diffuse radiation. The enhancement is more pronounced for small solar zenith angles. However, the effect from clouds appears to be smaller than influences of variations in the surface properties. The presentation aims to outline the measurement set-up and strategy, and to discuss preliminary results. Furthermore, the new, iterative coupling of the atmosphere and soil-vegetation model is presented, which aims to improve the understating of cloud-vegetation radiation interactions.
Multi-decadal changes in root zone water storage capacity through vegetation adaptation to hydro-climatic variability
Authors: Wang Siyuan , Hrachowitz Markus , Schoups Gerrit
Published: March 2024

Climate change can considerably affect catchment-scale root zone storage capacity (Sumax) which may further influence the moisture exchange between land and atmosphere, as well as stream flow and biogeochemical processes in terrestrial hydrological systems. However, direct quantification of the evolution of Sumax over multi-decadal time periods at the catchment scale has so far been rare. As a consequence, it remains unclear how climate change affects Sumax (e.g., precipitation regime, canopy water demand) and how changes in Sumax may control the partitioning of water fluxes as well as the hydrological response at catchment scale. The objectives of this study in the upper Neckar river basin in Germany are therefore to provide an analysis of muti-decadal changes in Sumax that can be observed as a result of changing climatic conditions over the past century and how this has further affected hydrological dynamics. More specifically, we test the hypotheses that (1) Sumax significantly changes over multiple decades reflecting vegetation adaptation to climate variability, (2) changes in Sumax control water availability for evapotranspiration and thus multi-decadal deviations from long-term average positions in the Budyko framework, (3) a time-dynamic implementation of Sumax affects the hydrological response, which in return can improve the performance of a hydrological model.We found that, indeed, a hydroclimatic condition considerably changed over time in the 1953 to 2022 study period, which was reflected by related fluctuations in the values of Sumax derived directly from observed water balance data These ΔSumax values varied by up to -20% in relatively wet decades to +20% in drier decades, which was very similar to ΔSumax obtained from calibration of a hydrological model (R2=0.95, p
Effects of Conceptual Model Structure Uncertainties on Actual Evapotranspiration Simulation
Authors: Wu Shuyue , Yang Yuting , Zhao Jianshi
Published: March 2024

Understanding the structural uncertainties within current conceptual hydrological models is crucial, as an appropriate model structure is essential for achieving accurate and reliable hydrological simulations. The development and evaluation of conceptual models have primarily focused on replicating streamflow dynamics, with less attention given to other important processes, such as the conversion from potential evapotranspiration (PET) to actual evapotranspiration (AET). This study assesses the performance of 33 existing conceptual model structures in simulating 8-day-scale AET across 671 catchments in the United States. These models are calibrated using both daily streamflow data and 8-day remote-sensing AET data. While most models demonstrate comparable performance in streamflow simulations, significant differences are observed in their performance in AET simulations. None of these models can consistently performs well in AET simulations across all 671 catchments, indicating that the “one-model-fits-all” assumption is not applicable. The performance of most models is found to be related to one or more catchment attributes. The most relevant catchment features are climatic, vegetation and topographical characteristics, including climatic aridity, precipitation seasonality, fraction of precipitation falling as snow, green vegetation fraction and catchment mean slope. In contrast to the “one-model-fits-all” assumption, catchments with distinct climatic, vegetation and/or topographical conditions require different ways to represent the AET process. Specifically, most models tend to underestimate AET in humid catchments where the majority of rainfall occurs in winter, except those account for interception evaporation. Additionally, models that explicitly include a vegetation transpiration component tend to perform better in catchments with denser vegetation cover. This work highlights the structure uncertainties related to AET simulations and may help model structure selections in a way to reasonably represent AET process.
Do non-conventional water resources lead to a better performance of irrigation communities? A comparative analysis between the regions of Murcia (Spain) and Apulia (Italy)
Authors: Ballesteros-Olza Mario , Stempfle Sarah , Blanco-Gutiérrez Irene , Gómez-Ramos Almudena , Giannoccaro Giacomo , De Gennaro Bernardo
Published: March 2024

In a context of growing global water demands, plus climate change affecting water resources availability, non-conventional water sources (like reclaimed water and desalinated seawater) are emerging as promising water supply alternatives. Given that agriculture is the major contributor to water withdrawals, this study analyzes if the use of non-conventional water for irrigation leads to a better performance of irrigation communities (ICs). To do so, the research includes several ICs from the Segura River Basin (southeast of Spain), a region with structural water deficit, which is pioneer regarding the use of non-conventional water; as well as ICs from the Apulia region (southeast of Italy), which also suffers from water scarcity problems, but is less experienced regarding the use of non-conventional water. A benchmarking analysis was carried out, based on a set of Key Performance Indicators (KPIs), such as irrigation efficiency, guarantee of water supply, energy costs or gross margin, among others. This methodology has been previously used in the framework of the water and drainage sector. Also, a Principal Component Analysis and Clustering Analysis were applied to explore potential dissimilarities between the studied ICs and their causes. Finally, a regression analysis was carried out to observe if the use of non-conventional water has any effects on the performance of the studied ICs. The results of this research may help to increase knowledge regarding the pros and cons of using these non-conventional water resources, depending on the socioeconomic, environmental and geographical context. This way, this study would contribute to promoting the use of non-conventional water in other regions, leaning towards a more sustainable use of water resources and, consequently, protecting and preserving water ecosystems.
Large-sample hydrology lessons
Authors: Berghuijs Wouter
Published: March 2024

The emergence of large-sample hydrology datasets has opened many new opportunities to derive more robust and more generalizable conclusions about hydrological processes and models. Here I showcase several examples of how large-sample hydrology can help unveil unknown hydrological behaviors, test and refine existing hypotheses, and challenge current modeling practices. Such advancements can include generating a better understanding of how climate, landscapes, and humans shape the diversity of hydrological conditions we encounter worldwide but can also focus on general emergent behaviors that are surprisingly similar between places. I also reflect on how large-sample hydrology datasets could evolve to become an even more productive playground for hydrology to advance.  
Simulating Differences in Helium Abundances between Fast and Slow Solar Winds
Authors: Thomas Simon , Rouillard Alexis , Lomazzi Paul , Poirier Nicolas , Blelly Pierre-Louis
Published: March 2024

To forecast the solar wind arriving at Earth in advance, and hence its impacts on technology, it is important to have a good understanding of how the solar wind is generated by the solar corona. Helium is a major constituent of the corona/solar wind that plays an important role in the energy budget of the corona and the acceleration of the solar wind. Helium abundance varies significantly with the solar cycle and in the different types of fast and slow solar winds. We present the newly-developed multi-species IRAP Solar Atmospheric Model (ISAM) which solves for the coupled transport of both neutral and charged particles between the chromosphere and the corona, including a self-consistent treatment of collisional and ionisation processes. We exploit ISAM to study the mechanisms that regulate Helium abundance in the source region of the fast and slow solar winds and contrast numerical results with and without Helium included in the model. We compare our model outputs with as many observations as possible, including Helios, Parker Solar Probe and Solar Orbiter data, in particular from the Proton and Alpha particle Sensor, SWA-PAS. We show that our simulations are in good agreement with previous studies, in particular that the solar cycle variation in Helium abundance can be explained by differences in abundance found for each solar wind type by ISAM, when just using diffusion in the model and not (yet) including the ponderomotive force. 
Impact of Subsurface Thermal Anomalies on Air Temperatures in Idealized Scenarios Using PALM-4U
Authors: Glocke Patricia , Holst Christopher C. , Khan Basit A. , Benz Susanne A.
Published: March 2024

The impact of underground heat (or cold) sources such as man-made infrastructures or geothermal systems have been extensively studied in geosciences. Soil temperatures near underground parking garages may be up to 10 K warmer than their surroundings. However, the coupling between these temperature anomalies in the soil and the atmosphere as a bottom-up scheme has been neglected so far. We investigated how this scenario can be modeled in the turbulence and building resolving large eddy simulation urban climate model PALM-4U and assessed the impact of modified soil temperatures on air temperatures in an idealized domain. Hereby, the soil temperatures at 2-meter depth were increased and decreased by 5 K, respectively. Multiple scenarios were considered, differentiating between cyclic and Dirichlet/radiation boundary conditions along the x-axis. Further, we ran the simulations under summer and winter conditions, day and night, and three land cover types which are bare soil, short grass, and tall grass. After three days of simulation time, cyclic boundary conditions induced air temperature anomalies due to changes in the subsurface temperature. However, Dirichlet/radiation boundary conditions did not show alterations. Analyzing the cyclic scenarios, although the absolute air temperature was significantly influenced by the landcover, the magnitude of the air temperature anomaly shows little variation. Daytime and seasonality exerted a greater influence on the magnitude. The greatest positive near-surface air temperature anomaly when increasing the soil temperature was 0.38 K for all land cover types and develops during winter between 09:00 and 10:00 CET. Smallest influence was found during summer at 09:00 CET, where increased soil temperatures resulted in a 0.02 K rise over short- and tall grass, and 0.18 K over bare soil. Conversely, decreasing soil temperatures showed predominantly inverse patterns.The findings contribute to the general comprehension of the coupling of soil- and atmospheric temperatures, inferring also insights of simulating idealized but reality-oriented scenarios in PALM-4U.
Retreat of Thwaites Glacier, West Antarctica, triggered by its neighbours.
Authors: Trevers Matt , Payne Anthony , Cornford Stephen , Gasson Ed
Published: March 2024

The drainage catchments of the neighbouring Thwaites and Pine Island Glaciers, situated in the Amundson Sea Embayment, West Antarctica, contain sufficient ice to raise global mean sea level by a meter. In recent years, significant scientific attention has been given to the potential for sustained retreat of these glaciers as a possible pathway towards widespread deglaciation of the marine-based West Antarctic Ice Sheet. Some recent studies have demonstrated that the Thwaites Ice Shelf provides only limited buttressing to the upstream grounded ice, suggesting limited sensitivity to the melt-driven loss of the ice shelf.We use the BISICLES ice sheet model to perform a series of 1000-year model experiments on the Amundson Sea domain. A synthetic sub-shelf melt rate is selectively applied to the Pine Island, Thwaites and Crosson/Dotson basins or combinations of those basins. We find that over millennial timescales, Thwaites is relatively insensitive to melt-driven thinning of its ice shelf, with its grounding line rapidly restabilising ~60km upstream of its current location. The same melt forcing applied to Pine Island Glacier leads to widespread deglaciation of the Pine Island catchment and significant retreat in the neighbouring Thwaites catchment despite the lack of melting there. Applying melting simultaneously in the Thwaites and Crosson/Dotson basins leads to widespread deglaciation that is much greater than the sum of its parts. This retreat is driven by a feedback between the ice fluxes crossing the basin boundary.We also conduct further experiments to determine the melt rates or additional processes required to trigger retreat of Thwaites Glacier in isolation. The results of our experiments support the suggestion that the Thwaites ice shelf provides limited buttressing, while also demonstrating that Thwaites is still vulnerable to retreat via other pathways.
Melt sensitivity of irreversible retreat of Pine Island Glacier
Authors: Reed Brad , Green Mattias , Jenkins Adrian , Gudmundsson Hilmar
Published: March 2024

In recent decades glaciers in the Amundsen Sea Embayment in West Antarctica have undergone substantial changes, including widespread retreat and acceleration. The subsequent mass loss caused the largest contribution to sea level rise from the entire Antarctic Ice Sheet. These changes have led to concerns about the stability of the region and the implications of future climate change. Recent modelling results show that one of the largest and fastest flowing of these glaciers, Pine Island Glacier (PIG), has already undergone an unstable and irreversible retreat in its recent history, when it detached from a subglacial ridge between the 1940s and 1970s.Here we use the ice-flow model Úa to study the sensitivity of this retreat to changes in basal melting. We show that an intermittent increase in basal melting would have been sufficient to force PIG into a retreat from its stable position on the ridge. Once high melting begins upstream of the ridge, only near-zero melt rates can stop the retreat. Our results suggest that unstable and irreversible responses to warm anomalies are possible, and this can lead to substantial changes in ice flux over relatively short periods of only a few decades.
Unraveling the hydrological dynamics of Lake Urmia: A comprehensive analysis of the impact of climatic changes and agricultural water extraction on lake level decline
Authors: Schulz Stephan , Darehshouri Sahand , Schröder Tanja , Hassanzadeh Elmira , Schüth Christoph
Published: March 2024

Lake Urmia, one of the largest hypersaline lakes on earth, known for its unique biodiversity, has experienced a profound and alarming decline in water levels over the last two decades, posing a huge threat to the lake's complex ecosystems. The causes of this decline are subject to controversy and vary between blaming mismanagement of water resources and attributing it to climate change. In order to find out the reasons for the drying up of Lake Urmia, we have conducted a series of studies to quantify the water balance components of Lake Urmia and analyze their temporal evolution and interaction over the last five decades. These studies encompass various methods, including the development of an improved bathymetric model using remote sensing data (Schröder et al., 2022), laboratory experiments to estimate the evaporation of the dried-up lake bed (Darehshouri et al., 2020, 2023) as well as setting up a water balance model, accompanied by a statistical analysis of lake inflow and meteorological variables (Schulz et al., 2020). Our results show that the fluctuations in the water levels of Lake Urmia during the study period are mainly related to weather conditions. Nevertheless, scenario simulations also revealed that agricultural water extraction, which has even exceeded the residual lake inflow in recent years, is also a decisive factor. The influence of irrigation water withdrawal on the volume of the lake can thus either strengthen the stability of the lake or accelerate its collapse. This differentiated understanding is essential for informed decision-making and sustainable management strategies to preserve or restore the ecological functioning of Lake Urmia.Darehshouri, S., Michelsen, N., Schüth, C., and Schulz, S.: A low‐cost environmental chamber to simulate warm climatic conditions, Vadose Zone Journal, 19, https://doi.org/10.1002/vzj2.20023, 2020.Darehshouri, S., Michelsen, N., Schüth, C., Tajrishy, M., and Schulz, S.: Evaporation from the dried-up lake bed of Lake Urmia, Iran, Science of The Total Environment, 858, 159960, https://doi.org/10.1016/j.scitotenv.2022.159960, 2023.Schröder, T., Hassanzadeh, E., Darehshouri, S., Tajrishy, M., and Schulz, S.: Satellite based lake bed elevation model of Lake Urmia using time series of Landsat imagery, Journal of Great Lakes Research, 48, 1710–1717, https://doi.org/10.1016/j.jglr.2022.08.016, 2022.Schulz, S., Darehshouri, S., Hassanzadeh, E., Tajrishy, M., and Schüth, C.: Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia, Scientific Reports, 10, 236, https://doi.org/10.1038/s41598-019-57150-y, 2020.
Optimal Transition Paths for AMOC Collapse and Recovery in a Stochastic Box Model
Authors: Soons Jelle , Grafke Tobias , Dijkstra Henk A.
Published: March 2024

The present-day Atlantic Meridional Overturning Circulation (AMOC) is considered to be a prominent tipping element and its collapse would have grave consequences on the global climate. Hence, it is important to determine probabilities and pathways for noise-induced tipping events. However, as there is no observational evidence for an AMOC transition over the historical period, a noise-induced transition is expected to be a rare event in models and simple Monte Carlo techniques are not suited for such low-probability events. Here, we use Large Deviation Theory to directly compute the most probable transition pathways for the collapse and recovery of the AMOC in a box model of the World Ocean calibrated to the FAMOUS-model, where we added stochastic freshwater forcing. This allows us to determine the physical mechanisms of noise-induced AMOC transitions. We show that the most likely path of an AMOC collapse starts paradoxically with a strengthening of the AMOC followed by an immediate drop within a couple of years due to a short but relatively strong freshwater pulse. The recovery on the other hand is a slow process, where the North Atlantic Ocean needs to be gradually salinified over a course of decades, and its dynamics are quite close to the recovery in a bifurcation tipping event. The proposed method provides several benefits, including an estimate of probability ratios of collapse between various freshwater noise scenarios, showing that the AMOC is most vulnerable to freshwater forcing into the Atlantic thermocline region.
Ground-based thermal mapping of Venus:  HDO and SO2 monitoring and upper limits of NH3, PH3 and HCN at the cloud top
Authors: Encrenaz Therese , Greathouse Thomas , Giles Rohini , Widemann Thomas , Bezard Bruno , Lefevre Franck , Lefevre Maxence , Shao Wencheng , Sagawa Hideo , Marcq Emmanuel , Arredondo Anicia
Published: March 2024

As part of a long-term monitoring program, full disk thermal maps of HDO (near 7 microns) and SO2 (near 7 and 19 microns) have been obtained at the cloud top of Venus in 2023, using the TEXES(Texas Echelon Cross-Echelle Spectrograph)  imaging spectrometer at the Infrared Telescope Facility (IRTF) at Mauna Kea Observatory. Assuming a constant D/H isotopic ratio, the water abundance has been more or less constant since 2018, at about half its value in 2012-2016. In contrast, the SO2 abundance, which was very high in 2018-2019 and very low between July 2021 and March 2023, has increased by a factor of about 5 between February and July 2023 (close to its maximum level of 2018-2019), and has remained at its high level in September 2023. The origin of these long-term variations is still unclear. In addition, stringent upper limits of NH3 (at 927-931 cm-1), PH3 (at 1161-1164 cm-1) and HCN at 744-748 cm-1) at the cloud top have been obtained in July 2023. These results will be presented and discussed.
Solar Wind - Venus Interaction During the Solar Maximum & Solar Minimum Periods: A Newly Developed Multi-Fluid MHD Model
Authors: Chen Nihan , Lu Haoyu , Li Shibang
Published: March 2024

A three-dimensional, four-species multi-fluid magnetohydrodynamic (MHD) model was developed to simulate the global interaction between the solar wind and Venus during the solar maximum and solar minimum periods. The model was augmented to incorporate the production and loss of the significant ion species in the Venusian ionosphere, i. e. H+, O2+, O+, CO2+, taking into account chemical reactions among all species. Results of simulated Venusian induced magnetosphere, which were validated by comparing with the observations from Venus Express, suggest that the shock locations are closer to the planet during the solar minimum condition, because the magnitude of electromagnetic forces in the minimum increased to counterbalance the heightened solar wind dynamic pressure. The Venusian ionosphere simulation results show that the ionospheric density profile is more condensed during solar minimum which are consistent with previous observations and simulations. Moreover, by taking advantage of our model, functions of electromagnetic forces acting on various ion species were analyzed to explore potential mechanisms behind the differences between these two solar wind conditions. The estimated ions escape rate is much higher for the minimum condition due to increased J×B forces within the magnetotail which are cause by the compressed magnetic field lines under higher solar wind dynamic pressures. This multi-fluid MHD model could serve as an efficient tool for exploring the fine structures of the Venusian space environment system and could also find applications in the future study of distinguishing impacts caused by the variation of a single parameter.
The effects of salinity and river runoff on idealized brackish ice-covered lakes 
Authors: Sharifi Fatemeh Sadat , Hinkelmann Reinhard , Hattermann Tore , Kirillin Georgiy
Published: March 2024

The effects of freshwater river runoff on dynamics of ice-covered brackish lakes have not been adequately studied to date. Compared to freshwater lakes, the circulation patterns in brackish lakes are complicated by non-linear effects of temperature and salinity on density stratification and mixing, and as a result on the ice melt. Quantifying these effects is essential for understanding circulation of large endorheic lakes in cold regions and their ecological and physical characteristics. We present modeling results on circulation caused by river runoff in a typical ice-covered brackish lake obtained with the Regional Ocean Modeling System (ROMS). The lake water salinity was set to 14 practical salinity units (PSU). In the initial state, the water temperature increased linearly from the freezing point at the surface to the temperature of maximum density, at the bottom, both accounting for the water salinity. Mixing of cold freshwater river inflow with the warmer saline waters produces negative buoyancy and downslope flow of dense currents near the river inlets with a secondary geostrophically-balanced circulation throughout the lake. We use the modeling results to quantify the contribution of this circulation mechanism on deep lake circulation and ventilation of the near-bottom waters.
The past and projected future freshwater flux from Arctic land ice
Authors: Bamber Jonathan , Zhang Zelu , Igneczi Adam
Published: March 2024

We have developed a freshwater flux (FWF) time series aimed at providing a benchmark data set for testing the sensitivity of ocean and coupled GCMs to realistic, plausible future FWF forcing alongside a 70 year reconstruction of past fluxes. Here we build on previous work that reconstructed the freshwater flux (FWF) from Arctic glaciers and the Greenland Ice Sheet from reanalysis (Bamber et al., 2018). First, we use ERA5 reanalyses, a regional climate model and satellite observations to reconstruct the FWF for all Arctic land ice from 1950-2021, partitioned into solid and liquid phases around the coastline of glaciated sectors of the Arctic. We then project the FWF forward until 2100 using estimates of Greenland Ice Sheet melt derived from a structured expert judgement assessment for two temperature scenarios that approximate business as usual and a Paris Agreement limit to warming (Bamber et al., 2019; Bamber et al., 2022). Fluxes from glaciers and ice caps (GIC) are derived from GIC projections for equivalent temperature scenarios. We develop projections for both the median and 95th percentile melt estimates to provide FWF forcing that encompasses the plausible future range from Arctic land ice. To achieve this, we assumed a linear increase in mass loss from 2021 onward such that the integral up to 2100 matches the estimates in the structured expert analysis. The geographic distribution of melt anomalies are scaled according to present-day anomalies in runoff and solid ice discharge from the ice sheet. For the high end case (business as usual, 95th percentile) this equates to a FWF anomaly from the Greenland Ice Sheet of about 0.16 Sv by mid century and 0.3 Sv by 2100, representing an unlikely but plausible FWF entering, primarily, the sub-polar North Atlantic. Bamber, J. L., M. Oppenheimer, R. E. Kopp, W. P. Aspinall, and R. M. Cooke (2019), Ice sheet contributions to future sea-level rise from structured expert judgment, Proc. Nat. Acad. Sci., 116(23), 11195-11200, doi:10.1073/pnas.1817205116.Bamber, J. L., M. Oppenheimer, R. E. Kopp, W. P. Aspinall, and R. M. Cooke (2022), Ice Sheet and Climate Processes Driving the Uncertainty in Projections of Future Sea Level Rise: Findings From a Structured Expert Judgement Approach, Earth's Future, 10(10), e2022EF002772, doi:https://doi.org/10.1029/2022EF002772.Bamber, J. L., A. J. Tedstone, M. D. King, I. M. Howat, E. M. Enderlin, M. R. van den Broeke, and B. Noel (2018), Land Ice Freshwater Budget of the Arctic and North Atlantic Oceans: 1. Data, Methods, and Results, Journal of Geophysical Research: Oceans, 123(3), 1827-1837, doi:10.1002/2017jc013605. 
Lateral and temporal variations in thrust belt behaviour in a low convergence retrowedge, north Pyrenees. 
Authors: Ford Mary
Published: March 2024

The Pyrenees is a collisional orogen built by inversion of an immature rift system during convergence of the Iberian and European plates from Late Cretaceous to late Cenozoic. The full mountain belt consists of the pro-wedge and foreland of the southern Pyrenees and the retro-wedge and foreland of the northern Pyrenees, where the inverted lower Cretaceous rift system is mainly preserved. Due to low overall convergence and absence of oceanic subduction, this immature orogen preserves one of the best geological records of early orogenesis, the transition from early convergence to main collision and the transition from collision to post-convergence. During these transitional periods major changes in orogen behavior reflect evolving lithospheric processes and tectonic drivers. These records are best preserved in the North Pyrenean Zone (NPZ), the retrowedge thrust belt and its adjacent syn-orogenic basin. This paper reviews along strike variations in structural and stratigraphic characteristics of the NPZ and adjacent basin evolution and explores the changing role in space and time of rheological, thermal and structural Inheritance and local and plate scale drivers.
Formation of the Hukou waterfalls by entrenchment due to a downstream integration process
Authors: Liang Hao , Zhang Ke
Published: March 2024

Waterfall represents a pulse of erosion by lowering the local base level, and produces fluvial terraces that serve as an agent to transfer tectonic, climatic, or autogenic signals upstream through a catchment. Although widespread creation, well-dated waterfalls in the trunk of world’s large river are numbered. This has led to rarity of trunk waterfall case studies, obscuring the resulting landform impacts during waterfall migration and therefore, hindering the exploration of their origins and mechanism. The Hukou Waterfall, situated downstream of the Jinshaan Gorge in the middle reach of the Yellow River, is a unique trunk waterfall. With its homogenous tectonic and bedrock conditions, no anthropogenic activities, and preserved fluvial terraces by retreating waterfall, the Hukou Waterfall provide opportunities to replicate the upstream migration process and associated landform response. Herein, we applied detailed field and DEM-based measurements and age constraints to construct dated longitudinal profiles throughout the Hukou Waterfall and downstream Jinshaan Gorge. We replicate two paleo-trunk in longitudinal profiles: (1) relatively low diachronous trunk (Ta) aged headward from ca. 245 ka to present-day with an average retreating rate and incision rate of 24.5 cm/a and 27.5 cm/ka, representing waterfall migration; and (2) relatively high isochronous trunk (Tb) aged ca. 2.5 Ma throughout the downstream of the gorge with a slow incision rate (8.0-8.7 cm/ka) occurred between Ta and Tb, suggesting a slow slip rate of bounding fault at the outlet of the Jinshaan Gorge. Replication of Ta shows analogous slope of riverbeds with Tb, implying that no waterfall commenced until ca. 245 ka in the downstream of Jinshaan Gorge. This study hypothesizes the Hukou Waterfall to have formed as a mid-Pleistocene rapid base-level-lower event. This event is likely ascribed to the entrenchment due to an integration process between the Fenwei Basin (local base level of the Jinshan Gorge) and the Sanmen Gorge (further downstream of the Fenwei Basin), which exposed the subsurface bedrock scarp produced by the faults accumulate slip.
Historical Flood Mapping Combining Radar Remote Sensing and Google Engine Technologies for The Kon and Ky Lo River Basin, South Center Coast Vietnam
Authors: Van Phan Tho , Anh Ngo Tu , Willems Patrick
Published: March 2024

Climate change has led to increasingly serious flooding in many regions around the world, including Vietnam. The Kon and Ky Lo river basins in Binh Dinh and Phu Yen provinces, Vietnam, have experienced increasingly serious flooding in recent years, which has caused damage to property and people living in the area. This basin lacks the availability of historical flood maps; flood information is mainly in the form of statistical information on people's damage situations.Floods in Vietnam often appear in the last months of the year, combined with storms and heavy rain, leading to more serious flooding. During such periods of heavy rain, measuring and monitoring the flood situation is very difficult. Currently, with the development of the European Space Agency's (ESA) radar Sentinel-1 remote sensing technology, flood monitoring has become more convenient compared to the use of optical remote sensing technology. Moreover, combined with Google Engine (GE) technology, mapping historical floods became easier.In this study, we applied the Sentinel-1 satellite images on the GE platform combined with SRTM digital elevation model data to conduct flood mapping for the large floods of 2016 and 2021 along the Kon and Ky Lo rivers. These historical flood maps will be used on the basis of flood risk assessment and as a basis for assessing the accuracy of future hydrological-hydraulic flood simulation models. In addition, the study also delineated areas that are frequently flooded to help local authorities more easily manage disasters and have better response solutions in the future, in order to limit the risk of damage to people in areas affected by flooding.
Quantifying the Stability of Refugee Populations: A Case Study in Austria
Authors: Ali Ola , Dervic Elma , Stütz Rainer , Nedelkoska Ljubica , Prieto-Curiel Rafael
Published: March 2024

The global surge in displacement, with nearly 110 million people uprooted due to violence, underscores the pressing need to comprehend the challenges faced by refugees. Population growth, environmental crises, and political instability contribute to this crisis, projecting an escalating trend in the decades ahead. While hosting countries strive to address concerns related to labour markets, state provisions, and cultural integration, understanding the well-being of refugees upon entry needs to be more adequately explored. This study focuses on refugee stability and integration, employing Austria as a case study. Utilising comprehensive administrative data spanning November 2022 to November 2023, we examine residence movements as a proxy for stability. Our findings reveal a stark contrast in the stability of refugees compared to other migrant groups. Analysing movement profiles, we establish that refugees exhibit significantly higher rates of residential mobility than their counterparts, especially among male refugees. This imbalance persists even when comparing refugees to migrants from top refugee-sending countries without official refugee status. This study contributes valuable insights into the intricate dynamics of refugee stability, shedding light on the enduring challenges faced by this population. By examining movement patterns as a key indicator, we provide a nuanced understanding of the residential experiences of refugees, that can inform targeted policies and interventions for enhanced refugee well-being and integration.
Reconciled regional & global glacier mass changes 2000−2022
Authors: Zemp Michael , Jakob Livia , Dussaillant Inés , Nussbaumer Samuel, U. , Dubber Sophie , Gourmelen Noel ,   GlaMBIE Team
Published: March 2024

Glacier changes are a sign of climate change and have an impact on the local hazard situation, region runoff, and global sea level. In previous reports of the Intergovernmental Panel on Climate Change (IPCC), the assessment of glacier mass changes was hampered by spatial and temporal limitations as well as by the restricted comparability of different observing methods. The Glacier Mass Balance Intercomparison Exercise (GlaMBIE; https://glambie.org) aims to overcome these challenges in a community effort to reconcile in-situ and remotely sensed observations of glacier mass changes at regional to global scales.In this contribution, we will present the approach and results of the new data-driven consensus estimation of regional and global mass changes from glaciological, DEM-differencing, altimetric, and gravimetric methods. Our reconciled estimate suggests a global glacier mass loss of about 5,500 Gt from 2000 to 2022, with an acceleration of about 25% when comparing the second with the first half period. Since 2000, glaciers regionally have lost between 1 and 30% of their total ice volume, and about 4.5% globally. We will discuss these results in view of differences between observation methods and in comparison to previous IPCC reports, the implications for regional glacier mass loss and global sea-level rise, and remaining opportunities for further research.
Physics-Informed Neural Networks for geoid modeling: preliminary results in Colorado
Authors: Jiang Tao , Tu Zejie , Dang Yamin
Published: March 2024

Although machine learning has become increasingly important in geodesy related fields such as geophysics, seismology and remote sensing, its applications in geodesy, especially in physical geodesy, are still in its early stages. The main reason for this can be attributed to the black box nature of pure data-driven machine learning, which lacks physical interpretability and credibility, making it difficult for machine learning approaches to be used in physical geodesy that takes reliability and accuracy as its core criteria. Physics-Informed Neural Networks (PINNs) is a class of deep learning algorithms aims to seamlessly integrate data and physical prior knowledge including ordinary or partial differential equations, it can yield more physically interpretable machine learning models that provide robust and accurate predictions. We present the PINN approach for gravimetric geoid modeling from Earth gravity model, terrestrial and airborne gravity datasets. A convolutional neural network (CNN) deep learning architecture is used, gravity measurements and physical laws are integrated by embedding the Laplace’s equation of disturbing potential and the fundamental equation of gravity anomaly into the loss function of the neural network using automatic differentiation. The PINN based geoid computation approach is tested in the area of the Colorado 1-cm geoid experiment. Simulated gravity observations and GNSS leveling derived geoid heights based on EIGEN-6C4 are used to validate the theoretical correctness and validity of the proposed PINN approach, and its performance on precise geoid modeling in this challenging area is evaluated using the actual terrestrial and airborne gravity observations, GNSS leveling measured geoid heights and high resolution DEM provided by NGS/NOAA.
Collection, Collation, and Comparison of 3D Coronal CME Reconstructions
Authors: Kay Christina , Palmerio Erika
Published: March 2024

Predicting the impacts of coronal mass ejections (CMEs) is a major focus of current space weather forecasting efforts. Typically, CME properties are reconstructed from stereoscopic coronal images and then used to forward model a CME's interplanetary evolution. Knowing the uncertainty in the coronal reconstructions is then a critical factor in determining the uncertainty of any predictions. A growing number of catalogs of coronal CME reconstructions exist, but no extensive comparison between these catalogs has yet been performed. Here we develop a Living List of Attributes Measured in Any Coronal Reconstruction (LLAMACoRe), an online collection of individual catalogs, which we intend to continually update. In this first version, we use results from 24 different catalogs with 3D reconstructions using STEREO observations between 2007-2014. We have collated the individual catalogs, determining which reconstructions correspond to the same events. LLAMACoRe contains 2954 reconstructions for 1862 CMEs. Of these, 511 CMEs contain multiple reconstructions from different catalogs. Using the best-constrained values for each CME, we find that the combined catalog reproduces the generally known solar cycle trends. We determine the typical difference we would expect between two independent reconstructions of the same event and find values of 4.0 deg in the latitude, 8.0 deg in the longitude, 24.0 deg in the tilt, 9.3 deg in the angular width, 0.1 in the shape parameter kappa, 115 km/s in the velocity, and 2.5e15 g in the mass. These remain the most probable values over the solar cycle, though we find more extreme outliers in the deviation toward solar maximum.