bluuebunny/crossref_metadata_2025 huggingface dataset:
Using synthetic EarthCARE Cloud Profiling Radar data to develop validation methodologies for ground-based cloud radar sites
Authors: Pfitzenmaier Lukas , Risse Nils , Kollias Pavlos , Puigdomenech Treserras Bernat , Schirmacher Imke
Published: March 2024

The value of permanent, multi-sensor surface-based observatories that collect continuous long-term observations for satellite L2 data products has grown significantly over the last 10-15 years. Examples of such established surface-based networks include the Aerosol, Clouds, and Trace Gases Research Infrastructure (ACTRIS) network, the US Department of Energy Atmospheric Radiation Measurements (ARM) observatories, and the recently established 94-GHz Miniature Network for EarthCARE Reference Measurements (FRM4Radar).The core of the work presented is the use of the developed transformation of suborbital to orbital radar data by Orbital-Radar. This simple L1 transformational operator converts L1 suborbital (ground-based or airborne) measurements to the EarthCARE Cloud Profiling Radar (CPR) L1 observations. The transformational operator ensures that the orbital to suborbital comparison accounts for differences in the sampling geometry, measurement uncertainty, and instrument sensitivity and simulates the impact of the surface echo. Furthermore, the operator simulates the EarthCARE characteristic reflectivity and Doppler velocity errors.Applying such a tool to long-time data sets allows to generate the optimal foundation for a statistical analysis of the EarthCARE CPR performance. Hence, the optimal sampling for CPR and ground-based data can be estimated, and the CPR detection of clouds and precipitation processes near the ground can be analyzed and evaluated. In addition, it shows how critical ground-based networks are and that they play an essential role in evaluating satellite measurements and products. Tools like Orbital-Radar may help evaluate future CPR satellite missions, expanding the L1 transformational operator to other spaceborne radar systems.
Oil spill risk assessment based on ocean model ensemble prediction system
Authors: Litzler Emma , Nepstad Raymond , Nordam Tor , Röhrs Johannes , Christensen Kai H. , Rikardsen Edel S. U.
Published: March 2024

Accidental oil spills at sea can have severe environmental impact on the marineenvironment. To help quantify the risk of petroleum activities, relevant oilspill scenarios are simulated ahead of time, to form a picture of possibleoutcomes, and to estimate needs for response equipment. Formally, anEnvironmental Risk Assessment (ERA) may be carried out, in which risk isquantified by estimating the environmental consequences of different outcomes,weighted by the probabilities of those outcomes.Probabilities in ERA are commonly determined by ensemble simulations with anoil spill trajectory model. Long time series of environmental data are producedfor the relevant area, and the oil spill scenario is simulated repeatedly atdifferent intervals within the environmental data set. Due to differences inwind, current and other environmental parameters, the outcome of a scenariowill be different each time, and each simulation in the ensemble constitutes asample from the space of possible outcomes.In this work, we run ensembles with the OSCAR oil spill model, using half ayear of data from 24 different ensemble members of an ocean model EPS (EnsemblePrediction System) setup for the Barents Sea. We demonstrate that in additionto the variation in outcomes from running simulations at different times, wealso get variation across the 24 different realisations of the environmentaldata. Assuming that each of the ensemble members are equally likely guesses atthe ocean state, the use of the EPS data as input to the oil spill simulationsallow us to explore a larger range of possible outcomes of the oil spill.The use of EPS in weather forecasting is already common practice, and availableto the public through ranges of uncertainty in weather apps. Given that thetransport of oil at the sea surface is to a large degree controlled by thewind, the use of EPS data in operational oil spill modelling of ongoing eventsis already possible. Making use of such data can help predict significant, butperhaps unlikely events, such as catastrophic oiling of sensitive beaches.
Constraining Vp and Vs structures using the dispersion of surface and leaky waves
Authors: Shi Caiwang , Chen Xiaofei , Li Zhengbo
Published: March 2024

The dispersion curves of surface waves have been widely used for the retrieval of subsurface structures. Because the surface-wave dispersion is not sensitive to Vp, classical dispersion inversion can only retrieve Vs structures. To retrieve Vp, the dispersion of guided-P waves, which belong to leaky waves, should be considered. Due to the difficulty in forward modeling, the quantitative analysis of the leaky-wave dispersion curves has been rarely reported. In this study, we first derive the sensitivity analysis method of the leaky-wave dispersion based on previously proposed the semi-analytical spectral element method. Then the quantitative sensitivity analysis of leaky-wave dispersion curves is carried out, which confirms the ability of guided-P wave dispersion to constrain the velocity structures. With the theoretical analysis, we propose a joint inversion method based on surface and guided-P wave dispersion curves, which can simultaneously retrieve Vp and Vs. To verify the effectiveness, the proposed joint inversion has been applied to different kinds of field data including ocean bottom seismometer data with active sources and the seismic data of Nevada in the United States in 2008. Both of the inversion tests show that the joint inversion of surface- and leaky-wave dispersion can effectively constrain the velocity structure of Vp and Vs at the same time, which helps to obtain more complete and accurate models than the traditional surface wave dispersion inversion.
Examining Interhemispheric Properties of the Cusp
Authors: Pham Kevin , Lotko William , Zou Ying , Zhang Binzheng , Varney Roger , Dredger Pauline
Published: March 2024

The magnetospheric cusp is a narrow region of geospace where the solar wind has direct access to the ionosphere and thermosphere. The low-altitude projection of the cusp is a site of concentrated energy dissipation, which leads to extraordinary thermospheric upwelling and prodigious outflows of ionospheric ions into the magnetosphere.  Although interhemispheric and seasonal differences in cusp morphology and properties are recognized, statistical empirical identifications and models do not properly capture important temporal and spatial features of the cusp.  We have analyzed cusp location, size and energization, and dynamics, using different identification methods applied to the Multiscale Atmosphere Geospace Environment (MAGE) global simulation model.  Interhemispheric differences are considered for a variety of seasonal and solar wind conditions.  Preliminary results indicate that under strong IMF By conditions, commonly used cusp identification methods do not agree and are associated with the direct-entry and Alfvenic cusps not being collated.  Furthermore, we find that the simulated cusp is not discernable in one hemisphere but is pronounced in the other hemisphere.  We explore under what conditions this occurs.
Improving ASCAT slope estimation methods for representing vegetation water dynamics
Authors: Frantzen Paco , Steele-Dunne Susan , Vreugdenhil Mariette , Hahn Sebastian , Quast Raphael , Wagner Wolfgang
Published: March 2024

Vegetation is a key part of the water and carbon cycle and the interaction between Earth's surface and atmosphere. Understanding water dynamics within vegetation is crucial for improving models that represent vegetation processes. Previous studies have investigated exploiting ASCAT scatterometer data from the METOP satellites to evaluate dynamics in vegetation water content. ASCAT has been operational since 2007 and captures microwave backscatter from multiple angles, revealing the relation between backscatter and the incidence angle. This relation reflects the relative contributions of volume and surface scattering—the former affected by water on and within vegetation, and the latter influenced by water in the top soil layer. Currently, a weighted regression using ASCAT observations from 42 days is used to estimate the parameters representing this relation: the slope and curvature, or the first and second order derivative of a second order Taylor approximation, respectively. This estimation method is implemented in the Soil Water Retrieval Retrieval Package developed by TU Wien.  Adverse artefacts of this estimation method are the aggregation of observations corresponding to varying states of the earth surface, e.g. before and after a forest fire. Here, we present results from a study to improve the estimation method for ASCAT's slope and curvature parameters, tailored to quantification of vegetation processes. Goals include: representing parameters at briefer temporal scales, reducing the impact of interception, and restricting temporal aggregation around instantaneous events of change such as storms. In addition to analysing real ASCAT observations, synthetic ASCAT observations are simulated using a radiative transfer model, enabling a thorough comparison of estimated slope against simulated ground truth values. Preliminary results show that simulated ASCAT slope time series represent the dynamics of real ASCAT slope, indicating that synthetic observations can be used to quantify improvement of the slope estimation method.
Anatomy of energy pathways in the subtropical North Atlantic
Authors: Tedesco Pauline , Gula Jonathan , Mashayek Ali
Published: March 2024

The North Atlantic is a central region in the global ocean circulation and for regulating our climate. Its circulation is constrained by energy transfers between time-mean currents, flowing at the basin scale, and time-varying (“eddy”) flows ranging from hundreds to order one kilometer. Eddy flows include low-frequency mesoscale and submesoscale currents and high-frequency internal waves. Here, we evaluate the eddy kinetic energy budget in the subtropical North Atlantic (ST) using two state-of-the-art numerical simulations, one without and one with a tidal forcing. We evaluate sources and sinks of energy, non-local effects — spatial energy redistribution — and eddy-mean energy conversions. We show that the energy budget varies within the ST, from the leading-order energy balances to the contributions of eddy flows. In the ST’s Interior, where submesoscale currents and internal waves dominate the eddy reservoir, the primary energy sources correspond to wind, tide, and baroclinic instability. At western and eastern boundaries, energy balances are the most complex. Mean-to-eddy energy conversion accounts for a substantial energy source, and non-local effects largely recirculate energy. At the western boundary, both energy contributions primarily involve mesoscale and submesoscale currents and internal tides (net contributions increased by a factor of 2 in the tidal scenario). At the eastern boundary, both energy contributions primarily involve internal tides (net contribution increased by a factor of 3-4 in the tidal scenario). Our results emphasise the substantial impact of internal tides on the time-mean circulation of the subtropical North Atlantic. This advocates for representing their contributions in ocean models, along with the ones of mesoscale and submesoscale currents.
Deformation microstructure of the fault rock drill cuttings from the enhanced geothermal system site in Pohang, South Korea
Authors: Jung Sejin , Kang Ji-Hoon , Kil Youngwoo , Jung Haemyeong
Published: March 2024

The 5.5 magnitude (Mw) earthquake in Pohang, South Korea in 2017 was one of the largest triggered earthquakes at an enhanced geothermal system (EGS) site. Faults that ruptured in Pohang were not identified by preliminary geological investigations or geophysical surveys, and the subsequent study of the fault rocks at the Pohang EGS site was limited to depths of 3790–3816 m. In this study, we present new observations of fault rocks from drill cuttings retrieved from the Pohang EGS. The drill cuttings obtained from 3256 to 3911 m contained “mud balls,” which showed a clay matrix with foliation and a cataclastic texture, indicating a typical fault gouge or breccia. Furthermore, the mud ball samples retrieved from depths of 3256 m and 3260 m contained black fragments. Scanning and transmission electron microscopy revealed that the black fragments consisted of glass-like material, which is indicative of frictional melting during coseismic slip (Jung et al., 2023). The presence of these black fragments suggests that at least one seismic event had occurred at the Pohang EGS site prior to the hydraulic stimulation test.Jung, S., J. -H. Kang, Y. Kil and H. Jung, 2023, Evidence of frictional melting in fault rock drill cuttings from the enhanced geothermal system site in Pohang, South Korea. Tectonophysics, 862, 229964.
Wind tunnel experiments to characterize snow densification and SSA reduction caused by aeolian snow transport
Authors: Walter Benjamin , Wahl Sonja , Weigel Hagen , Löwe Henning
Published: March 2024

Snow precipitation frequently occurs under moderate to strong wind conditions, resulting in drifting and blowing snow. Processes like particle fragmentation and airborne metamorphism during snow transport result in microstructural modifications of the ultimately deposited snow. Despite the relevance (optically and mechanically) of surface snow for alpine and polar environments, this effect of wind on the snow microstructure remains poorly understood and quantified. Available descriptions of snow densification due to wind are exclusively derived from field measurements where conditions are difficult to control. Information on the effect of wind on the specific surface area (SSA) is basically nonexistent. The goal of this experimental study was to systematically quantify the influence of wind on the surface snow density and SSA for various atmospheric conditions (temperature, wind speed, precipitation intensity), and to identify the relevant processes. We conducted experiments in a cold laboratory using a closed-circuit ring wind tunnel with an infinite fetch to investigate wind-induced microstructure modifications under controlled atmospheric, flow and snow conditions. Artificially produced dendritic nature-identical snow was manually poured into the ring wind tunnel for simulating precipitation during the experiments. Airborne snow particles are characterized by high-speed imaging, and deposited snow is characterized by density and SSA measurements resulting in a comprehensive dataset.            The high-speed images support a snow particle transport scheme in the saltation layer similar to natural conditions. We measured an increase of the densification rate with increasing wind speed which differs from available model parameterizations. The SSA was found to decrease under the influence of wind, while increasing wind velocities intensified the SSA decrease. For higher air temperatures (Ta > -5°C), both the densification and SSA rates significantly differ from the rather constant rates at lower temperatures. We attribute this to the effects of enhanced cohesion or sintering (density) and intensified airborne snow metamorphism (SSA) at higher air temperatures. A sensitivity experiment revealed a strong influence of airborne snow metamorphism on the SSA decrease. Our results provide a first step towards an improved understanding and modeling of the effect of aeolian snow transport on optically and mechanically relevant microstructural properties of surface snow.
Initial stress distribution dictates nucleation location and complexity of the seismic cycle of long laboratory faults
Authors: Paglialunga Federica , Passelegue Francois , Violay Marie
Published: March 2024

Many aspects of earthquake physics are still not completely understood given its intrinsically complex nature. Among the others, the nucleation process; when and where an earthquake will occur, as well as its magnitude. Seismology is a commonly used method for studying earthquakes, but it faces challenges in accessing precise information about the physical processes taking place on the fault plane.Here, we show how laboratory seismology can directly shed light on fault plane dynamics. Our approach involves reproducing in the laboratory on a large biaxial apparatus with a fault length of 2.5 m generated by two analog (PMMA) samples brought into contact. The experimental setup allows to impose both a heterogeneous loading distribution through the use of independent pistons loading the fault in the normal direction and specific boundary conditions (i.e. by modifying stopper and puncher dimensions). The stress state is measured through strain gauges at high frequency (40 KHz) along 15 locations along the fault. The experiments provide insights into two crucial aspects of laboratory earthquakes: (i) the nucleation location of ruptures and (ii) the complexity of the seismic cycle.Our findings reveal that the initial on-fault stress distribution plays a significant role in both aspects. We observe that ruptures consistently nucleate in locations where the stress ratio τ/σn is the highest. Notably, such values change among experiments, challenging the widespread notion that a friction coefficient solely governs the onset of instability. Furthermore, we demonstrate how the heterogeneity of the initial prestress distribution along the fault controls the complexity of the seismic cycle. In certain cases, the seismic cycle manifests as system-size events with complete ruptures occurring regularly in time, devoid of precursors. Conversely, other initial stress distributions generate more complex cycles, characterized by multiple precursors before a main rupture, predominantly occurring in zones of elevated τ/σn (referred to as 'friction asperity'). The complexity of the seismic cycle can be described in terms of the number of precursory events, inter-event time, and the size of finite ruptures.This study, carried out in a long laboratory fault, highlights the complexities that emerge when heterogeneous, hence more realistic, stress conditions are applied, providing valuable insights into the physics of natural earthquakes.
Optically stimulated luminescence dating of loess sequences in the Tibetan Plateau and their palaeoenvironmental implications
Authors: Yang Shengli , Liu Li , Li Qiong , Li Pushuang , Luo Yuanlong
Published: March 2024

The Tibetan Plateau (TP) is extremely sensitive to climate change. Widely loess deposits distributed in the Tibetan Plateau are important archives for studying the past environmental changes of the Tibetan Plateau. However, little information is understood due to the poorly age constrained of the TP loess. In this study, we use the single-aliquot regenerative dose optically stimulated luminescence (OSL) method, and the post-infrared infrared stimulated luminescence protocol (pIRIR) to date the well-preserved loess–paleosol sequences in the eastern TP and discuss the applicability and reliability of OSL dating of the TP loess for establishing a reliable numerical age framework. We found that quartz OSL signal of TP loess is dominated by fast component, and the equivalent dose can be measured by SAR method. The growth curve shapes and saturation dose shows that the quartz OSL signal in this region saturated at ~200～230 Gy. The prior-IR stimulation plateau test, dose recovery, recycling ratio and recuperation indicated that pIR200IR290 could be used for the equivalent dose estimation of potassium feldspar. Our results contribute to an improved understanding of the TP dust history and paleoenvironmental changes in the Last Glacial cycles.
Effects of land use change on dry heathland soil moisture in a changing climate
Authors: Shaeffer René , Rineau Francois , Soudzilovskaia Nadia
Published: March 2024

Conversion of natural and semi-natural systems to agricultural use is one of the largest conservationchallenges of our time. As the world’s population continue to grow at unprecedented rates,multinational organizations like the United Nations and its subsidiary the Food and AgricultureOrganization call for higher crop production and the expansion of existing agriculture to ensure futurefood security, especially in the face of changing climate. However, these efforts will most likely endangernumerous landscapes of historical and cultural value, including those found in northwest Europe. Howthese possible changes in land use may alter the functions of these ecosystems and the associatedservices they provide are questions that need to be answered before any policy decisions can be made.Using a state-of-the-art ecotron facility, we compared soil moisture profiles between an intact dryheathland system and heathland soils that had been cleared for cereal agriculture, both of which weresubjected to climate conditions projected for the year 2070, in line with the IPCC RCP8.5. Aftercontinuously monitoring moisture changes in the top 1.5 meters of soil for three years, we found thatthere are significant differences between the two modes of land use. Soils used for cereal crops weresignificantly drier (up to >60%) in the upper 10-20cm than intact heathland soils, and significantly wetter(up to >500%) at the lowest soil levels (140cm). This redistribution of moisture within the soil columnunder different land use schemes can have serious implications for overall ecosystem functioning,particularly with regard to potentially mitigating heathland soils’ ability to store and capture carbon andexacerbating detrimental soil-climate feedbacks under agricultural use.
Improving the representation of apparent anelastic attenuation variability in regionalised Ground Motion Models in Europe with a focus in mainland France
Authors: Georges Pauline , Kotha Sreeram Reddy , Chaljub Emmanuel
Published: March 2024

The complex physics of earthquake rupture, wave propagation and site effects are simplified and modelled into generic Ground-Motion Models (GMMs) for use in seismic hazard and risk assessment. However, the complexity of geology and seismicity in Europe leads to a high variability in the ground motion prediction compared to observed data. Recent GMMs partially resolved this variability by regionalising their model and adapting to the specificity of each region. We focus this study on the apparent anelastic attenuation variability, to understand the underlying physics of wave propagation in the crust and better model the variability in GMMs. The regionalisation model used in the recent European Seismic Hazard Maps 2020 (ESHM20) divides Europe in several polygons, each with a specific apparent anelastic coefficient adjustment. This model has certain limitations due to ambiguity in the criteria to define these polygons, which have led to non-reproducible maps and geologically diverse regions being grouped into a single large polygon, especially in France. Two hypotheses have been made to improve the current regionalisation. Firstly, France was divided following the contrast of Rayleigh wave velocity in the ambient noise tomography of France. Secondly, a null hypothesis was defined where no prior geological information is used, and Europe is simply regionalised into a regular grid. Linear mixed-effects regressions were performed on the pan-European ground-motion dataset, complemented with a French dataset, to quantify the apparent anelastic attenuation variability. The regionalisation based on Rayleigh wave velocity captures attenuation variability better than the current model for France. However, the grid-based regionalisation is more accurate in the representation of the attenuation variability which leads to keep this choice as the best regionalisation. Analyses of variance statistics confirmed this result. The size of the grid was also discussed based on these statistical tests and the number of records. The apparent anelastic attenuation variability captured on a regular grid can now be examined for a physical meaning producing this variability and improve the parametrisation of GMM.
SAR imagery and deep learning techniques for reservoir monitoring in Korea
Authors: Kim Wanyub , Kim Doyoung , Kim Yeji , Kim HyunOk , Choi Minha
Published: March 2024

Agricultural reservoirs are key structures for water supply on the Korean Peninsula, where the water resources are concentrated seasonally. Monitoring of agricultural reservoirs is essential for efficient management of available water resources. However, in the case of the Korea, there are many unmeasured reservoirs without observation facilities, so it is difficult to monitor available water at a regional scale. Remote sensing-based reservoir monitoring that can observe the water surface in a wide area is essential. In the case of Synthetic Aperture Radar (SAR) image, continuous water body detection is possible regardless of weather conditions. Recently, water body detection research using AI techniques has been actively conducted to improve accuracy. In this study, water body detection was performed on an agricultural reservoir using Sentinel-1 SAR image and AI-based U-net, HR-Net, and Swin-Transformer techniques. The water/non-water binary classification images from the Sentinel-2 satellite were used for validation. In addition, time series validation was performed using in-situ reservoir storage and evaluated the performance of each deep learning techniques. If SAR image with high spatial and temporal resolution can be utilized in the future, it is expected that more efficient management of available water resources will be possible.Keywords: Sentinel-1, SAR, Deep learning, Water body detection, ReservoirAcknowlegment: This work was supported by the “Development of Application Technologies and Supporting System for Microsatellite Constellation”project through the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2021M1A3A4A11032019). This research was supported by the BK21 FOUR (Fostering Outstanding Universities for Research) funded by the Ministry of Education (MOE, Korea) and National Research Foundation of Korea (NRF). This work is financially supported by Korea Ministry of Land, Infrastructure and Transport (MOLIT) as 「Innovative Talent Education Program for Smart City」
Responses of biogenic volatile organic compound emissions and surface ozone air pollution in the Greater Bay Area to heatwaves
Authors: Zhang Jingwei , Zhai Shixian , Tai Amos P. K.
Published: March 2024

Land cover has significant impacts on local meteorology and biogenic volatile organic compounds (BVOCs) emissions, which in turn affects surface ozone air quality. The Guangdong-Hong Kong-Macau Greater Bay Area (GBA) is a hotspot of ozone air pollution, where BVOCs play an important role. The importance of BVOCs in ozone air pollution strengthens during heatwaves, and heatwaves have been increasing in frequency and intensity in the past two decades. Therefore, it is critical to have accurate BVOCs emissions in atmospheric chemistry models for simulating ozone air quality and supporting the design of efficient ozone air pollution control strategies. However, current BVOCs emissions derived from the outdated and coarse (0.25° x 0.3125° spatial resolution) Community Land Model version 4.5 (CLM4) plant functional types (PFT) map based on Moderate Resolution Imaging Spectroradiometer (MODIS) land cover dataset in 2000 is far from sufficient for producing an accurate BVOCs emission inventory in the GBA. What is more, the CLM4 BVOCs emissions do not consider the substantial land cover change in the GBA in the past two decades, thus incapable of simulating ozone responses to land cover change on a decadal timescale. In this study, we employ the 30m Finer Resolution Observation and Monitoring of Global Land Cover (FROM_GLC2017) map for simulating meteorology with the WRF model and deriving an updated BVOCs emission inventory with MEGAN for September 2017, during which time a one-week heatwave event happened in the GBA. The online two-way coupled regional meteorology-chemistry model WRF-GC v2.0 with the detailed Greater Bay Area anthropogenic emission inventory (GBA-EI) reproduces the MDA8 ozone during non-heatwaves (r = 0.71, NMB = 4.21%), but has significant low biases for MDA8 ozone during heatwaves (r = 0.26, NMB = 27.32%). We find that updating the land cover data from U.S. Geological Survey (USGS) and CLM4 to FROM_GLC2017 is promising to correct the biased low ozone during heatwaves. Compared with the original USGS land cover map, broadleaf evergreen tree forest cover, which has a high BVOCs yield and responds swiftly to temperature increase, increases by 37.29%. Concurrently, the cropland cover, which has a relatively low BVOCs yield, decreases by 44.62%. We will go on to investigate how land cover changes affect ozone trends in the GBA in the past two decades with the long-term FROM_GLC2017 land cover dataset.
Potential Groundwater Recharge at the Scale of France:  Characterization and Future Trends in the Context of Climate Change
Authors: Robelin Olivier , Lanini Sandra , Caballero Yvan , Sauquet Éric
Published: March 2024

The quantification of present and future groundwater resources at regional scale is necessary for the implementation of national climate change adaptation plans. We present a method to compute the potential groundwater recharge (PGR) by precipitation applied specifically to the scale of France.A simple water balance approach taking into account the maximum soil water content capacity and the land use is first applied to derive the effective rainfall estimation from the SAFRAN national meteorological reanalysis. The BaseFlow Index (BFI) computed over 611 French river basins with minor human influence on discharge is then used to assess the effective rainfall infiltration ratio for watershed with homogeneous geological lithologies. This infiltration ratio is finally applied to convert effective rainfall into potential recharge at the scale of each groundwater body in France.A sensitivity analysis of BFI (to the automated BF separation method, the length of discharge time series, etc.) was performed. The low annual variability and uncertainty on BFI estimates allow us to consider, as an initial approximation, that the infiltration ratio remains constant over time.To validate this global approach, in the framework of the Explore2 project, we compared computed effective rainfall and potential recharge with alternative potential recharge estimates simulated by a set of hydrological models under current condition (1976-2005). Previous computed variables have been compared with SURFEX physical surface model solving energy balance over the entire re-analysis (1958-2020). Additionally, we used Euro-Cordex climatic projections as input of our model to evaluate the future potential groundwater recharge (2021-2100). Future evolution of potential recharge shows contrasting situations between the North and the South of France which were not highlighted by previous assessments.
Numerical Simulation of CO2 Storage Behavior: Investigation of Physical and Geochemical Trapping in Heterogeneous Underground Structures
Authors: Kung Ching-En , Kuo Chia-Wei , Yang Yun-Chen
Published: March 2024

Large-scale carbon capture and storage (CCS) stands a crucial role in achieving net-zero emissions by 2050. To successfully deploy the geological CO2 storage, it is essential to consider heterogeneities of storage reservoirs and surrounding strata. The variation of porosity, permeability, relative permeability, and capillary pressure have a significant influence on storage capacity, potential leakage, CO2 plume migration, and risk assessment. Besides, underground aqueous CO2 can convert to minerals or form insoluble ionic species if reacting with specific ions or solid minerals. These processes, known as geochemical trapping, is considered as the most permanent form of storage.In this work, we utilize the well-known multiphase flow software TOUGH3 as well as reactive-transport software TOUGHREACT with module ECO2N, to simulate the behavior of CO2 injected into the 2D large-scale models comprising aquifer, seal, and reservoir layers with homogeneous distributions.  A series of sensitivity studies on porosity-permeability relations, different pairs of relative permeabilities and different heterogeneous distributions generated from a geostatistical software SGeMS will be conducted in this work to investigate their impacts on CO2 plume migration and pressure evolutions.  In addition, capillary trapping mechanisms are also simulated based on sensitivity studies on different capillary pressure curves. Finally, brine with different concentration species is considered to simulate the geochemical trapping.This research aims to achieve the following objectives: 1. Examine the impact of uncertainties of petrophysical properties and heterogeneities. 2. Analyze preliminary results of predicted pressure buildup and saturation distribution in the heterogeneous models. 3. Evaluate the possible storage capacity of both physical and geochemical trapping.
A framework for the territorial landslide early warning system implementation: applications, lessons learnt and future challenges
Authors: Rossi Mauro , Marchesini Ivan , Brunetti Maria Teresa , Peruccacci Silvia , Balducci Vinicio , Guzzetti Fausto
Published: March 2024

As prioritized by the Sendai Framework, enhancing disaster preparedness is fundamental for the effective response, for taking actions in anticipation of events, and to ensure that the appropriate capacities are in place for effective response and recovery at all levels. Under this view early warning systems can be seen as irreplaceable tools to supporting the Civil Protection authorities in the preparedness and response phases. This is particularly relevant for the case of rainfall-induced slope failures that occur worldwide every year, claiming lives and causing severe economic disruption. Implementing early warning systems to forecast the occurrence of such geo-hydrological phenomena is difficult and challenging both from the scientific and technological side. Here we present a framework developed in Italy for the operational forecasting of rainfall induced landslides over large areas, which includes (i) models tools and technological supports for landslide prediction; (ii) algorithms for nowcasts and forecasts production using diversified inputs; (iii) operational early warning system procedures and technological supports for landslide forecasting; (iv) interfaces for the query and analysis of the early warning system outputs; (v) criteria, tools and technological supports for the validation of the early warning system outputs. The main lessons learned in the last two decades during the implementation of such framework are presented and discussed, highlighting the possible future challenges.
InSAR Decomposition Reveals Varied Deformation Patterns in Coastal Subsidence Regions
Authors: Lin Shao-Hung , Hung Wei-Chia , Hu Jyr-Ching
Published: March 2024

The impact of climate change was reported to cause more frequently extreme rainfall or drought events in decades. The disaster like typhoon coming up with excessive rainfall would flood low-lying coastal areas, resulting in devastating damage to local industry. Moreover, the coastal area may also be threatened by relative sea level rise due the lowering land surface height by land subsidence hazards. The Pingtung Plain, one of the major aquaculture-rich counties in Taiwan, suffered from up to 3.5-meter cumulative subsidence in the coastal area from 1972 to 2019. Featuring tropical monsoon climate properties, the land displacement in Pingtung area is highly variated with interannually seasonal changes between dry and rainy seasons. In this study, we apply Persistent Scatterer InSAR (PSI) technique into the high variability coastal area to make up for the lack of either spatial or temporal resolution of in-situ grounded measurements like continuous GNSS station or precision leveling. To comprehensively analyze the transient land deformation responded within a short period, we further employ an unsupervised decomposition method called Principal Component Analysis (PCA) into InSAR observation matrix to distinguish individually spatiotemporal patterns. First two principal components (PCs) reveal that the coastal and inland area in the Pingtung Plain characterize different amplitude of seasonal variations and long-term trends. In addition, the third principal component indicates the heterogeneous patterns due to different types of industrial groundwater usage and hydrogeological environment. The unsupervised method is capable to retrieve different spatial deformation patterns in the high variability coastal area from the bulk InSAR time-series matrix, which can contribute to comprehensive understandings of the relation between land deformation and aquifer system.
Exploring Mantle Dynamics of the Cascadia Subduction System through Anisotropic Tomography with Transdimensional Inference Methods
Authors: VanderBeek Brandon , Del Piccolo Gianmarco , Faccenda Manuele
Published: March 2024

The Cascadia subduction system is an ideal location to investigate the nature of mantle flow and associated driving forces at a convergent margin owing to the dense network of on- and off-shore seismic instrumentation. While numerous shear wave splitting and tomography studies have been performed with these data, they have produced conflicting views of mantle dynamics collectively referred to as the Cascadia Paradox. On the overriding plate, splitting observations are consistent with large-scale 3D toroidal flow while off-shore splitting patterns are more easily explained by 2D plate-driven flow. Either geometry is difficult to reconcile with seismic tomographic models that image a fragmented Juan de Fuca slab descending beneath the Western USA. However, these observations offer only an incomplete image of Cascadia mantle structure. Shear wave splitting provides a depth integrated view of anisotropic fabrics making inferences regarding the 3D nature of mantle deformation difficult. Prior high-resolution body wave tomography typically neglects anisotropic effects which can in turn yield significant isotropic imaging artefacts that complicate model interpretation. To overcome these limitations, we invert P-wave delay times for a 3D hexagonally anisotropic model with arbitrarily oriented symmetry axes using the reversible jump Markov chain Monte Carlo algorithm. This stochastic imaging approach is particularly well-suited to the highly non-linear and under-determined nature of the anisotropic seismic tomography problem. The resulting ensemble of solutions allows us to rigorously assess model parameter uncertainties and trade-off between isotropic and anisotropic heterogeneity. We investigate whether the fragmented nature of the subducted Juan de Fuca slab is a well-resolved feature and to what extent its geometry trades off with anisotropic parameters. In light of our new 3D anisotropic model, we re-evaluate the Cascadia Paradox and attempt to reconcile disparate views of Western USA mantle dynamics.
3-D Modelling of Plume-Lithosphere Interaction: The Cosgrove Track, Eastern Australia
Authors: Duvernay Thomas , Davies D. Rhodri
Published: March 2024

Compared to oceanic hotspot tracks, volcanic provinces within Earth's continents generally exhibit more intricate surface characteristics, such as spatio-temporal distribution and geochemical signatures of erupted lavas. These complex surface patterns relate to dynamic interactions in the uppermost convective layer of the mantle, where decompression melting occurs. The Cosgrove Track of Eastern Australia constitutes a compelling example of such continental volcanic activity. Recent studies support a mantle plume having sustained the volcanism and discuss several notable features, such as lithosphere-modulated volcanic activity, plume waning, separate volcanic tracks, and plate-motion change.Here, we simulate the proposed interaction between the Cosgrove plume and eastern Australia during the past 35 Myr. We design a 3-D analogue of the Australian continent using available lithospheric architecture determined through seismic tomography and impose the inferred plate motion associated with this region. Our models incorporate updated peridotite melting and melt chemistry parameterisations that provide quantitative estimates of generated melt volume and composition. We find that plume-driven and shallow edge-driven melting processes, modulated by the lithospheric thickness of the Australian continent, combine to explain the observed volcanic record. Our preliminary results agree well with surface observations and provide further insight into the geodynamics of eastern Australia.
Measurement of evapotranspiration on small urban surfaces. Application to green roofs.
Authors: Ramier David , Rodriguez Fabrice , Keravec Pascal
Published: March 2024

The greening of cities has become a major component of current urban development policies. This greening is taking new and variable forms, and is increasingly associated with rainwater management techniques. This increase in vegetated surfaces can potentially encourage evapotranspiration. Increasing this process has a twofold advantage. On the one hand, It provides stormwater runoff reduction benefits and, on the other, it promotes cooling in the urban environment. However, in order to better quantify and optimise evapotranspiration, it is necessary to be able to measure it for different kind of urban surfaces. In an urban environment, where surfaces are very heterogeneous, it is therefore necessary to have continuous measurements, over the long term (several seasons) and, if possible, on different types of surfaces with relatively small areas: just a few dozen m².
In order to verify whether Eddy Covariance measurements can be adapted to these singular surfaces, measurements were carried out on a green roof (situated in Broué (28), France) covering an area of approximately 1900 m² (16.5 m x 115 m) during the summers of 2022 and 2023. Two measurement systems were used (an IRGASON from Campbell Scientific and a Gill WindMaster associated with a LI-COR LI-7500). In an attempt to limit the footprint to the roof surface, the instruments were placed at a height of 50cm above the roof surface.
In addition to these measurements, the energy balance was monitored and complementary measurements were made using a transpiration chamber. The latent heat flux measurements obtained by EC indicate fluxes generally below 150 W.m2, which represents between 10 and 45% of the net radiation depending on the soil water content. Comparison with the transpiration chamber shows that the latter underestimates the fluxes compared with the EC measurement.
However, the final objective is to determine whether measurements at such a low height are realistic and can limit the footprint at the roof surface, spectral analyses of these measurements and footprints are currently being studied.
A catalogue of wind events for assessing the connectivity among Marine Protected Areas in the German Bight (North Sea)
Authors: Rubinetti Sara , Sidorenko Vera , Arnone Enrico , Androsov Alexey , Beng Kingsly C. , Klemm Kerstin , Sell Anne F. , Akimova Anna , Pineda-Metz Santiago E. A. , Pogoda Bernadette , Brand Sarah , Wegner Mathias , Shama Lisa , Laakmann Silke , Horn Sabine , Wiltshire Karen H.
Published: March 2024

Marine protected area (MPA) networks are fundamental for restoring and conserving ecosystem functions like biodiversity and general ecosystem health. Ideally, the effects of local conservation measures are not limited to one particular MPA alone but influence and connect regions beyond, or even other MPAs, through the spreading, replenishment and potential recovery of populations and communities. Connectivity defines, in a probabilistic sense, the functional linkage exchange between individual MPAs or key regions, and it depends on the features of the selected tracers (including the specific biological traits of target organisms), but it is also to a large degree determined by the hydrodynamic circulation patterns in the area. For the German Bight (south-eastern North Sea), we are focusing in particular on potential spillover from a restoration site for the European flat oyster (Ostrea edulis) through the spread of planktonic life stages. The circulation regimes are determined mainly by tidal and wind forcings. The prevailing wind-driven surface circulation in the area is cyclonic, influenced by frequent south-westerly to westerly winds. However, winds from other directions, for instance from the North-West, have the potential to modify and even reverse this circulation pattern. Wind intensity and directions have a clear seasonal variability, with higher magnitudes in winter and lower in summer, but also exhibit a significant interannual variability driven by the strength and location of high and low mean sea level atmospheric pressure centres. Moreover, winds from the East are relatively rare compared to the other patterns but can be extremely persistent (up to hundreds of hours) and thus affect the hydrodynamics and, hence, the connectivity between the MPAs. In this study, we catalogued the wind events according to their typical duration and magnitude using 10m eastward and northwards components retrieved from ERA5 reanalysis data and characterized them according to their seasonality and interannual variability. The results can be used to define realistic atmospheric scenarios to numerically simulate the sea dynamics in the southern North Sea and, consequently, assess the connectivity among different sites, including established MPAs. These efforts are crucial for a proper planning of conservation and restoration measures in the German Bight, which is one of the most exploited marine regions in the world. 
Bayesian optimization of ocean mixed layer parameterizations
Authors: Mrozowska Marta , Jochum Markus , Avery James , Stoustrup Ida , Nuterman Roman
Published: March 2024

Global climate is highly sensitive to tropical sea surface temperature. Accurately representing the tropical SST remains a significant challenge for general circulation and climate models. One of the largest sources of uncertainty is the vertical turbulent mixing. To accurately represent the distribution of ocean mixed layer depths, turbulence closure schemes necessitate careful tuning. This is most commonly done manually by comparing with mixed layer depth climatologies. Advancements in machine learning research introduce a new strategy: automated tuning. Veropt, an add-on to the python ocean model Veros, uses Gaussian processes to emulate an objective function in a multi-dimensional parameter space. We present a surprising combination of changes to the default parameters of the commonly used turbulent kinetic energy (TKE) closure scheme that minimise the model bias in tropical mixed layer depth.