bluuebunny/crossref_metadata_2025 huggingface dataset:
Sedimentary facies and depositional environments of the Upper Triassic carbonate-evaporite succession in the Honaz Mountain Range (SW Anatolia, Turkey) 
Authors: Alçiçek Hülya , Spina Amalia , Cirilli Simonetta , Yılmaz İsmail Ömer , Capezzuoli Enrico , Brogi Andrea , Liotta Domenico , Alçiçek Mehmet Cihat
Published: March 2024

The Upper Triassic carbonate-evaporite-bearing succession in the Honaz Mountain Range (HMR) in SW Anatolia (Turkey), exists as a tectonic slice within the carbonate and ophiolithic units of allochthonous Lycian Nappe stacks. It comprises interbedded layers of sulphates (gypsum) and limestones or dolostones. Sedimentological and palynofacies analyses suggest that the Honaz succession was deposited in the more protected areas of the peritidal zone of a shallow inner ramp under a tropical/arid climate. Three main subenvironments are identified based on facies and microfacies associations: (i) Sabkha, exhibiting two distinct microfacies-gypsum and peloidal packstone/grainstone, (ii) Tidal flat, consisting of six microfacies-cryptalgal boundstone, fenestral bindstone, laminated peloidal mudstone, laminated algal/microbial boundstone, pisolite rudstone, and carbonate breccias, (iii) Lagoon, featuring five microfacies-laminated peloidal packstone/grainstone, crinoidal wackestone/packstone, mudstone, bioclastic packstone, and ostracodal/peloidal packstone to grainstone. The succession is characterized by meter/submeter-scale cyclic facies alternations, similar to Lofer cycles, Dolomia Principale/Hauptdolomit Formation, and Dachstein Formation of European basins.Facies and petrographic analyses, along with Sr isotope ratios of dolomites, indicate early dolomitization from evaporated seawater in this environment (shallow seepage reflux or evaporative-drawdown). However, the depletion in δ18O (-11.53 to -5.46 ‰, mean -8.29 ‰), and slightly radiogenic Sr isotope values of dolomites are attributed to a recrystallization process, occurring at high temperatures during burial diagenesis. The relatively high δ13C values (+0.76 to +3.60 ‰, mean +2.42 ‰) suggest dolomite alteration in a relatively closed system. The microfacies of the Honaz succession are comparable to those in other Upper Triassic successions (e.g., western Carpathians, Italian Apennines, Spain, northern Calcareous and southern Alps, external Dinarides and Hellenides, southwestern Germanic Basin, Morocco, Israel, Albany) deposited under similar environmental conditions. Comparing facies with those from other coeval sequences allows us to delineate such carbonate-evaporite shallow water platforms on the northern margin of the Neotethys Ocean. This study was supported by the Pamukkale University BAP Research Project (2022ÜBBİD001).
Performance assessment of a conceptual model to simulate fluxes in the unsaturated zone to better represent runoff and infiltration processes
Authors: Kootanoor Sheshadrivasan Veethahavya , Langhammer Jakub , Vlček Lukáš , Šípek Václav
Published: March 2024

In continuation to the previously presented methodological approach to estimate vadose zone boundary fluxes titled “A novel conceptualization to estimate unsaturated zone mass-fluxes and integrate pre-existing surface- and ground- water models” at the EGU GA 2022, and the performance assessment thereof showcased at the EGU GA 2023, titled “Performance assessment and Benchmarking of a conceptually coupled groundwater - surface-water model”, this study aims to assess the performance of the proposed methodology to couple surface- and ground- water models aims to investigate its local performance in a soil-column by comparing the results of a controlled simulation with that of HYDRUS-1D. To recap, the initial study presented a conceptual numerical scheme that aimed to adequately estimate the in- and out- fluxes of the Unsaturated Zone (UZ) with the primary aim of coupling existing groundwater (GW) and surface-water (SW) models. It was expected that such a numerical scheme would provide a viable alternative to solving the computationally expensive Richard’s model for cases where description of fluxes within the UZ and the spatial description of the soil moisture were not in the interest of the modeller. Examples of such cases would be efforts to model the hydro(geo)logical effects of various climate-scenarios, efforts to estimate GW recharge dynamically, and efforts to design integrated watershed management design structures and systems, among others. The model, and in effect, the methodology, established its capacity to simulate the fluxes of the UZ for the Tilted-V theoretical catchment setup during its comparison against the physically based ParFlow model, in the previous study. However, it also did demonstrate certain crucial shortcomings that arose from the nature of the coupling scheme (loose coupling - where the models ran consecutively until the end of a timestep, exchanged information, and continued so and and so forth until the end of the simulation period) used to couple the two GW and SW models. In this study, the authors aim to more effectively assess the methodology, by attempting to simulate a real-world scenario of transport of water fluxes in the subsurface of a Spruce/Beech Stand in a Peatland experimental site in the Bohemian Forest region of Czechia. The model setup involves the simulation of fluxes in a 1D soil profile using the said methodology and also using the HYDRUS-1D modelling software and comparing the results of the two models and the results with observations. It is expected that such a setup should provide a robust assessment of the methodology. The discussion shall be an extensive analysis of the obtained results. The authors also hope that the study fosters discussions to unify the polarising modelling approaches as outlined in Markus Hrachowitz er al., 2017.
Recognition of the solar activity manifestation in the interplanetary space at joint data analysis from SWA-PAS and MAG instruments of the Solar Orbiter mission.
Authors: Yakovlev Oleksandr , Dudnik Oleksii
Published: March 2024

The shock waves, spatial regions with magnetic field perturbations and irregularities, and other phenomena characterizing the environment in the heliosphere can occur during enhanced solar activity. Clarifying the reasons for these events allows us to better understand the interconnection between processes on the Sun and interplanetary space.In our study, which is based on the data processing from both SWA-PAS and MAG instruments we examine variations of the different parameters of the solar wind and interplanetary magnetic field derived as a result of in-situ measurements aboard the Solar Orbiter in the first half of 2023.In the period selected both instruments detected the events with significant variations of the key parameters of the solar wind befriended by specific changes in the magnetic field components. We demonstrate the most outstanding examples of the SWA-PAS and MAG data analysis allowing the identification of the ICME, shock waves, CIR, magnetic clouds, magnetic flux ropes, magnetic holes, and other Heliospheric phenomena with confidence. The particular interest is in the selected simultaneous or serial registration events of the two or more mentioned phenomena presented.This work is supported by the “Long-term program of support of the Ukrainian research teams at the Polish Academy of Sciences carried out in collaboration with the U.S. National Academy of Sciences with the financial support of external partners”.
Climate-induced variations in arthropod habitats of the Circum-Sicilian islands according to convection permitting simulations of the Mediterranean driven by CMIP6 and PMIP4 data
Authors: Ciarlo James , Coppola Erika , Micallef Aaron , Mifsud David
Published: March 2024

Arthropods play vital roles in the ecosystem (e.g., pollinators, decomposers, biological pest control), and thus can act as indicators of ecosystem integrity. The state of these ecosystems is sensitive to variations in climate conditions, especially on small islands. The Circum-Sicilian islands are a chain of small islands around Sicily in the central Mediterranean. With the use of Convection permitting simulations, many of these islands can finally be adequately resolved. The objective of the project PALEOSIM (PALEOclimate modelling of Small Islands in the Mediterranean and possible impacts on arthropod habitats) is to study climate impacts on the habitats of arthropods (mainly insects) in the Circum-Sicilian islands. To achieve this, RegCM5 is driven by CMIP6 and PMIP4 data for a 3 km region covering the west and central Mediterranean.Climate indices from the simulations have been used to assess the ecological niche of select arthropod species and hence determine how these conditions have changed across different time scales. The data used to drive RegCM5 allows for the study of time slices across several scenarios, which include: the last glacial maximum, mid-Holocene, ~1000 CE, ~1850 CE, ~1995 CE (a historical baseline), and Global Warming Levels of 1.5, 2, and 3 °C. This analysis reveals how some species are especially sensitive to changes in climate conditions, and the significant threat of the current climate crisis.
The mutual feedback mechanism between CO2 and multiphase fluids during CO2 injection into shale oil reservoirs
Authors: Lin Xuan , Li Zhuo
Published: March 2024

CO2 injection can effectively promote the development and utilization of shale oil. The interaction between CO2, shale oil and pore structure has attracted much attention as a key mechanism for oil resource exploitation. Therefore, we established a pore network model, injected shale oil and CO2 successively into the model, and studied the occurrence state of miscible fluid at the nanoscale. This study takes the shale of Lucaogou Formation in Jimsar Sag of Junggar Basin as the research object. Nano-CT and scanning electron microscopy are used to observe the pore structure of shale layer by layer, and the pore structure is transformed into a molecular model layer by layer, and finally superimposed into a pore network molecular model. Through the analysis of crude oil group components and chromatography-mass spectrometry, the characteristics of crude oil components are identified and the corresponding molecular models are established. The occurrence state of shale oil in the pore network model is simulated by molecular dynamics. CO2 is injected into the system to simulate the occurrence state of the miscible fluid. The fluid density in the system is analyzed, the interaction force between CO2, shale oil and pore structure is calculated, and the capacity models of adsorbed oil, free oil and CO2 storage are established. The reliability of the model is verified and applied by combining production data and experimental tests. This study plays a crucial role in advancing the understanding of CCUS (carbon capture, utilization, and storage) and the geological theory of shale oil and gas. It also has the potential to overcome the challenges and limitations in shale oil production technology, thus making significant contributions to this field.
Unrevealing Seismogenic Sources of Historical Earthquakes: New Insights from the Elusive 1706 Maiella Earthquake (Abruzzi Region, Central Italy)
Authors: Volatili Tiziano , Gironelli Veronica , Luzi Lucia , Galli Paolo , Carafa Michele , Tondi Emanuele
Published: March 2024

The Inner Abruzzi region ranks among Italy's highest seismic hazard areas, hosting a system of SW-dipping normal faults historically active with moderate-to-large earthquakes (Mw ≥ 5.5). The L’Aquila earthquake in April 2009 (Mw = 6.3) intensified interest in assessing active fault seismogenic potential. Despite extensive studies, the Maiella Massif's historical seismicity, notably the 1706 and 1933 earthquakes (Mw ~6.8 and 5.9, respectively), causing severe damage, remains elusive. The investigation of historical seismic events, such as the 1706 earthquake within the Maiella area, aligns with the pressing need to identify and characterize potential seismogenic sources of future seismic activity. This task is often hindered by the scarcity of unambiguous evidence or quantitative data at both near-surface and seismogenic depths. Many source hypotheses, possibly related to the 1706 earthquake, are present in the literature. These structures, with different geometrical parameters, depths, and kinematics, characterized the tectonic setting of this region.This study offers a comprehensive overview of these hypotheses in assessing the 1706 earthquake’s source. Their 3D geometrical representation was modelled, considering the available geological and geophysical information. The resultant seismic scenarios were estimated in terms of macroseismic intensity by calculating peak ground motion values (i.e., PGV, PGA) for each point within the 1706 macroseismic field. This procedure incorporates site amplification effects into the synthetic ground motion calculations at each site within the macroseismic field, coupling a Vs,30 map of the Italian territory. Finally, the determination of the best source model involves assessing the misfit (residuals) between the simulated macroseismic intensities and the observed ones. The accuracy of the simulated macroseismic field in reproducing the real field is evaluated by calculating the residual mean and the root-mean-square error (RMSE).The study outcomes highlight the complexities in determining the exact source of the 1706 earthquake. Despite detailed modelling efforts, discrepancies in intensity distributions and the absence of recent seismic activity on specific faults pose uncertainties in understanding seismicity in the Inner Abruzzi area. While contributing to the ongoing debate, the research underscores the need for further investigations to better constrain the seismic hazard of this region.
Irrigation expansion in North China Plain has historically decelerated regional warming and mitigated temperature extremes
Authors: Yuan Tiangang , Tai Amos P K , Wu Jin
Published: March 2024

Since the 1950s, global irrigated area has expanded dramatically, with complex effects on regional climate worldwide. The North China Plain (NCP) is among the most intensively irrigated regions in the world, but the effects of historical irrigation expansion on climate extremes over multi-decadal timescale are largely uncertain. Combining statistical methods with model simulations, we found that NCP experienced a decreasing trend of 0.2–0.25 ℃ decade−1 (p < 0.1) in daily maximum temperature (Tmax) during May-June of 1961–2000 along with irrigation expansion, which is distinct from other regions experiencing strong warming such as most of western China. The cooling effect on Tmax is 0.092 ℃ decade−1 (p < 0.01), relatively lower than that in California’s Central Valley but comparable to the trend in Northwest China and larger than the trend in Tibetan Plateau. The correlation coefficients between irrigation expansion and temperature change from 1960 to 2000 for Tmax and mean air temperature (Tmean) are –0.58 and –0.33 (p < 0.01), respectively, suggesting the ability of irrigation to alleviate regional warming and temperature extremes. Such effect varies over time, continuously strengthening from 1961 to 1980 because of intensive irrigation expansion, but then remaining relatively unchanged or weakening during 1980–2005 with moderate expansion. After 2005, the cooling effect is not detectable, which implies that it is completely canceled out by other forcings such as greenhouse gas warming, compensation of urban area expansion, small irrigation expansion rate and decline in irrigation water use. Despite that, irrigation is still able to reduce the number of extreme heat days after 1980. Compared with other factors, we found that irrigation expansion is the second most important contributor (27%) to the decrease in Tmax during the study period, after aerosol pollution (54%). This work emphasizes the ability of irrigation expansion to adapt agriculture to climate change over the past decades, and highlights the need for sustainable irrigation expansion in the future.
Water table height maps prediction from passive surface-wave dispersion using deep learning
Authors: Cunha Teixeira José , Bodet Ludovic , Rivière Agnès , Dangeard Marine , Hallier Amélie , Gesret Alexandrine , Dhemaied Amine , Boisson Gaboriau Joséphine
Published: March 2024

Monitoring underground water reservoirs is challenging due to limited spatial and temporal observations. This study presents an innovative approach utilizing supervised deep learning (DL), specifically a multilayer perceptron (MLP), and continuous passive-Multichannel Analysis of Surface Waves (passive-MASW) for constructing 2D water table height maps. The study site, geologically well-constrained, features two 20-meter-deep piezometers and a permanent 2D geophone array capturing train-induced surface waves. For each point of the 2D array, dispersion curves (DCs), displaying Rayleigh-wave phase velocities (VR) across a frequency range of 5 to 50 Hz, have been computed each day between December 2022 and September 2023. In the present study, these DCs are sampled in wavelengths ranging from 4.5 to 10.5 m in order to focus the monitoring on the expected water table depths. All VR data around one of the two piezometers is used to train the MLP model. Water table heights are then predicted across the entire geophone array, generating daily 2D piezometric maps. Model's performance is tested through cross-validation and comparisons with water table data at the second piezometer. Model’s efficiency is quantified with the root-mean-square error (RMSE) and the coefficient of determination (R²). A R² is estimated above 80 % for data surrounding the training piezometer and above 55 % for data surrounding the test piezometer. Additionally, the RMSE is impressively low at 0.03 m at both piezometers. Results showcase the effectiveness of DL in generating predictions of water table heights from passive-MASW data. This research contributes to advancing our understanding of subsurface hydrological dynamics, providing a valuable tool for water resource management and environmental monitoring. The ability to predict 2D piezometric maps from a single piezometer is particularly noteworthy, offering a practical and efficient solution for monitoring water table variations across broader spatial extents.
Analysis-Ready EO Data: A Standards-Centric Perspective
Authors: Baumann Peter
Published: March 2024

Data about the Earth are too difficult to access, making EO exploitation inaccessible for non-experts and tedious for experts. Reasons are manifold, from intrinsic complexity to technically overloaded handling where data are presented more in a generator-centric than a user-centric manner. Under the headline of Analysis-Ready Data (ARD) significant research is going on to find ways of stripping off unneccesary burden from services.While progress is being made on improving metadata, such as by CEOS, the data perspective still is underrepresented. With our research we aim at contributing to closing this gap in particular on gridded data, so rasters and datacubes. Starting point is the data and processing model the ISO/OGC coverage standards offer; in these ecosystems, three use cases are inspected: determination of service quality parameters, automated data fusion, and ML. We find that some ARD aspects are covered, but we also spot several issues that deserve investigation and standardization effort. Broadly, these fall into the following categories:conceptual clarification, ex: pixel-in-center / pixel-in-corner;
enhancing existing (and otherwise proven) standards, ex: establish a framework for units of measure amenable to autoamtic conversion, similar to coordinate reference systems;
improved standards governance, ex: avoiding competing standards known to be not interoperable.
In our talk we present results achieved from work in OGC Testbed-19 and EU FAIRiCUBE. We discuss gaps found and present suggestions for improvement towards easier and more reliable consumption of EO data by humans and machines. 
The quandary of detecting the signature ofclimate change in Antarctica
Authors: Casado Mathieu , Hébert Raphael , Faranda Davide , Landais Amaelle
Published: March 2024

Global warming driven by human activities is expected to be accentuated in polar regions compared with the global average, an effect calledpolar amplification. Yet, for Antarctica, the amplitude of warming is still poorly constrained due to short weather observations and the largedecadal climate variability. Using a compilation of 78 ice core records, we provide a high-resolution reconstruction of temperatures over thepast 1,000 years for seven regions of Antarctica and direct evidence of Antarctic polar amplification at regional and continental scales. We alsoshow that the amplitude of both natural and forced variability is not captured by the CMIP5 and six model ensemble members, which could beexplained in part by the Southern Annular Mode. This shows that failing to consider the feedback loops causing polar amplification could lead toan underestimation of the magnitude of anthropogenic warming and its consequences in Antarctica.
Understanding the interaction between inland waters and the coastal zone during extreme events over the Po Delta from space
Authors: Tarpanelli Angelica , De Biasio Francesco , Nielsen Karina , Filippucci Paolo , Cavalli Rosa Maria , Vignudelli Stefano
Published: March 2024

The alternation of extreme events is a source of great stress on the territory and forces us to adopt solutions to help mitigate their consequences. In this study, an attempt is made to exploit Earth Observation from space as a means to point out the interaction of inland waters and the coastal areas during hydrological extreme events, i.e. floods and droughts. During a flood event, large volume of water from the river reaches the coast, adding a considerable volume of freshwater. Conversely, during a drought event salt water from the sea enters inland causing severe damage to agriculture and the local population. With this study we attempt to investigate how the systems of sea and river interact during particularly intense events using satellite optical (Sentinel-2 and Sentinel-3) and altimeter (Sentinel-3, Cryosat-2, Icesat-2) sensor data. The area selected is the Po River delta (up to 200 km from the mouth), which in recent years has been exposed to severe events: in November 2019, the Po River was subject to a copious flood that had not occurred since 2000, while in the summer of 2022, it experienced the worst drought in the last 70 years.The analysis aims at evaluating three fundamental aspects: 1) the ability of satellite altimetry to identify extreme events in the river; 2) the potential of satellite altimetry to detect salt wedge intrusion in the Po River delta; and 3) the potential correlation between the altimetry observations and optical imagery of the river’s plume along the Adriatic coast.The analysis was conducted by analysing long time series (of about 10 years) for the first objective and by focusing on the drought event of 2022 and the flood events that occurred in the last 5 years for the other two objectives.The results of the analysis confirm that the satellite observed the significant increase and decrease in water levels in correspondence of the extreme events. In addition, the analysis of the data at the virtual stations in the downstream part of the Po River, together with the data along the tracks crossing the plume closer to the mouth of the river, showed the interaction between the sea and the river. In particular, the temporal series of the river clearly highlight the influence of the sea water several km upstream the river (more than 40 km as reported in the news), probably related to the salt wedge intrusion, which has caused significant damage to agriculture and drinking water aquifers for a long time after the event. The study qualitatively shows that extreme hydrological events can also be captured in the open sea in this region.The analysis illustrates the great potential of satellite sensors to monitor extreme events and the interaction of inland and coastal waters.
Machine learning for predicting spatially variable lateral hydraulic conductivity: a step towards efficient hydrological model calibration and global applicability
Authors: Ali Awad M. , Imhoff Ruben O. , Weerts Albrecht H.
Published: March 2024

Recent advances in the application of machine learning techniques to estimate soil hydraulic properties using soil datasets have shown promising results. PedoTransfer Functions (PTFs) can facilitate the mapping of the complex relationship between soil properties and soil hydraulic properties, e.g., lateral hydraulic conductivity—a necessity for estimating lateral subsurface flow in spatially distributed hydrological models like wflow_sbm. The vertical-to-horizontal saturated hydraulic conductivity ratio (fKh0) is crucial for model calibration, but an established PTF is currently lacking. Our objective is to investigate the potential of ML algorithms in estimating PTFs for fKh0 prediction. First, optimized fKh0 across Great Britain (GB) resulting from a sensitivity analysis of the wflow_sbm model (Weerts et al., 2024) were used to train two ML algorithms; Random Forest (RF) and Boosted Regression Trees (BRT), using seven soil parameters from SoilGrids v1.0. Both algorithms effectively predicted fKh0 of 92 subbasins (i.e., test set of 25%) with high performance as compared against the optimized values, and RF slightly outperformed BRT. As a next step, we compared wflow_sbm simulated discharge results using uncalibrated fKh0 (default value of 100) and predicted values. The predictions notably improved wflow_sbm predictive accuracy by rising the median KGE from 0.55 (using uncalibrated fKh0) to 0.75 (using predicted fKh0). Following, we generated two globally distributed fKh0 maps, allowing us to further investigate the transferability of the ML-based PTFs. Therefore, we tested the predicted fKh0 across 559 gauge stations within the Loire basin in France. The utilization of either RF or BRT improved performance in around 75% of these subbasins with a KGE that was, on average, 0.06 higher. Furthermore, fKh0 prediction uncertainty and the impact of model spatial resolution were further analyzed. In conclusion, our study demonstrates the potential of ML methods to find relationships between soil properties and (model) soil hydraulic properties, which assists in parameter estimates for distributed hydrological models in gauged and ungauged basins.
Parameterized orographic gravity wave drag controls extratropical stratospheric dynamics in CMIP6 models.
Authors: Šácha Petr , Hájková Dominika
Published: March 2024

Orographic gravity waves (OGWs) are an important mechanism for coupling of the free atmosphere with the surface, mediating the momentum and energy transport and influencing the dynamics and circulation especially in the stratosphere and above. Current global climate models are not able to resolve a large part of the OGW spectrum and hence, OGW effects have to be parameterized in the models. Typically, the only parameterized effect is the OGW induced drag. Despite producing the same quantity as an output and relying on similar assumptions (e.g. instantaneous vertical propagation), the individual OGW parameterization schemes differ in many aspects such as handling of the orography, the inclusion of non-linear effects near the surface and the tuning of the emergent free parameters.This presentation introduces a recently published study by the authors, reviewing 7 different parameterizations used in 9 different CMIP6 models and reporting on pronounced intermodel differences in the vertical distribution and magnitude of the parameterized OGW drag that are partly tuning-dependent. Finally, we demonstrate how the OGW drag differences project to the intermodel differences in the stratospheric dynamics, documenting the crucial importance of the lower- stratospheric OGW drag that controls the resolved wave propagation from the troposphere to the stratosphere in both winter hemispheres.
Unveiling land degradation neutrality: a nonlinear perspective framework for unexpected land degradation in Kazakhstan
Authors: Sun Qiangqiang , Sun Danfeng , Zhang Ping , Lin Xin , Jiao Xin
Published: March 2024

The unexpected land degradation in dryland regions has become a focal issue of global climate change and human activity since the onset of the Anthropocene. Therefore, conducting land degradation assessments from a nonlinear perspective is crucial to achieve the goal of Land Degradation Neutrality and Sustainable Development Goal (SDG 15.3.1). The monitoring framework that integrates land cover, land productivity, and soil organic carbon has emerged as the primary model for assessing land degradation neutrality, relying on the evolving trends from time-series data. However, these frameworks currently lack time-series data for soil organic carbon and overlook nonlinear state transition thresholds in the evolution of land systems, resulting in considerable uncertainty in land degradation assessments. Here, basing on the space-for-time substitution theory, we establish a framework for assessing land degradation states primarily using static data that are derived from soil organic carbon, net primary productivity, and our obtained physically meaningful endmember fraction using spectral mixture analysis model. This framework emphasizes the nonlinear evolutionary characteristics and thresholds among these three variables to quantify stable and unstable states during land degradation and their corresponding thresholds. Utilizing three widely used data sources—Soilgrid 250m, MOD17A3, and internally produced bare soil fractions products—and focusing on Kazakhstan as our study area. Soil organic carbon represents the system state variable and net primary productivity alongside bare soil fraction serve as environmental variables, we identify two state transition thresholds of soil organic carbon as slow variable of complex system (4.1% and 1.6%). This allows us to delineate the study area into two stable states: one representing an ideal state dominated by forest and agricultural land cover (23.72%), and the other depicting a completely degraded area dominated by desert cover (19.71%). The remaining areas between these two stable states constitute the unstable state, posing certain degradation risks. Building upon this, we further utilize a self-organizing neural network to integrate these three variables and assess the degree of degradation in the unstable areas, classifying them into severe, moderate, and mild degradation, accounting for 16.51%, 55.82%, and 27.67%, respectively. This space-for-time substitution method overcomes the challenges posed by the absence of time-series data, assisting a more spatially diversified approach to achieve land degradation neutrality assessment during the Anthropocene.
Quantifying sources of subseasonal prediction skill in CESM2
Authors: Richter Jadwiga , Glanville Anne , King Teagan , Kumar Sanjiv , Yeager Stephen , Duan Yanan , Fowler Megan , Jaye Abby , Edwards Jim , Caron Julie , Dirmeyer Paul , Danabasoglu Gokhan , Oleson Keith
Published: March 2024

Subseasonal prediction fills the gap between weather forecasts and seasonal outlooks. There is evidence that predictability on subseasonal timescales comes from a combination of atmosphere, land, and ocean initial conditions. Predictability from the land is often attributed to slowly varying changes in soil moisture and snowpack, while predictability from the ocean is attributed to sources such as the El Niño Southern Oscillation. Here we use a unique set of subseasonal reforecast experiments with CESM2 to quantify the respective roles of atmosphere, land, and ocean initial conditions on subseasonal prediction skill over land. These reveal that the majority of prediction skill for global surface temperature in weeks 3-4 comes from the atmosphere, while ocean initial conditions become important after week 4, especially in the Tropics. In the CESM2 subseasonal prediction system, the land initial state does not contribute to surface temperature prediction skill in weeks 3-6 and climatological land conditions lead to higher skill, disagreeing with our current understanding. However, land-atmosphere coupling is important in week 1. Subseasonal precipitation prediction skill also comes primarily from the atmospheric initial condition, except for the Tropics, where after week 4 the ocean state is more important.
Probabilistic projections of winter floods considering cumulative effect of air temperature changes
Authors: Li Lingqi , Xu Chong-Yu
Published: March 2024

Ice-induced winter flooding, intensified by sustained low temperatures, holds the potential for severe natural disasters, but is seldom explored probabilistically considering warming climate impacts. This study established both marginal and copula-based joint probability distributions of the upstream (QH) and downstream (QL) ice-induced floods in the Lower Yellow River, a hanging river above the ground, under four parametric scenarios (constant, time as covariates, mean air temperature as covariates, and accumulated negative air temperature as covariates), to compare historical and design flood regimes using six inference methods (UNI, OR, AND, KEN, SKEN, and COND) under air temperature changes. The results show that the Lognormal and Weibull marginal distribution models with accumulated negative air temperature as covariate parameters were optimal for QH and QL, respectively and the positive dependence between QH and QL was best described by the Gumbel-Hougaard copula. Impacts of increasing air temperature on flood downtrends and yearly change-points (1990 for QH and 1985 for QL) reduced both historical QH-QL flood magnitude combinations and projected return periods, thus denoting declining flood severities over time. Due to such flood downtrends, the most probable composition (MPC) values of 100-year design floods varied from the highest (1656 m3/s for QH and 1645 m3/s for QL using the OR method) to the lowest (624 m3/s for QH and 342m3/s for QL using the SKEN method). The average decreasing rates of MPC values before and after the discerned flood change-points were 17.4% for QH and 39.6% for QL. When conditioned on the occurrence of upstream QH having flood magnitudes less than 100-year design floods, large floods downstream exceeding a 50-year return period were inferred as improbable. This study can provide a paradigm of flood projections to meet diverse flood control objectives under changing climate.
Assessment of the evolution of groundwater quality for the state of California, United States using weighted index overlay analysis
Authors: Das Anisha , Banerjee Dolon , Ganguly Sayantan
Published: March 2024

One of our planet’s most significant and important widely available resources is groundwater, which is also a major global source of water for domestic, agricultural and industrial uses. Subterranean aquifers typically provide over 40% of the water consumed by California’s towns and farmers, and a substantial amount more during the drought years. Since aquifers are influenced by both natural and anthropogenic processes, groundwater pollution is a major issue worldwide. Ecosystem functions, human health, and socio-economic development, all depend on the quality of the water that it used in different sectors. In order to guarantee the safe and sustainable use of these resources for a variety of purposes, it is crucial to evaluate and monitor the quality of groundwater. In this study, the groundwater quality for the state of California, United States was evaluated using Weighted Index Overlay Analysis to establish the suitability of it for human consumption. The dataset utilized in the study was hosted by the California State Water Resources Control Board (CSWRCB).Groundwater data collected from CSWRCB website on physiochemical parameters, such as total dissolved solids, total hardness and main cations like Ca2+, Mg2+, Na+ & K+ as well as anions like HCO3-, Cl-, SO42- & NO3-  were analysed to determine the quality of groundwater in California. Using the Inverse Distance Weighted (IDW) approach for interpolation, spatial maps were generated in ArcMap. In accordance with WHO drinking water quality guidelines, weights have been allocated to several physiochemical characteristics for the Weighted Index Overlay Analysis (WIOA).  California's groundwater quality's temporal variation is assessed for last 15 years to investigate the evolution of groundwater usability for drinking in the state.                                                                                Figure 1. Flowchart showcasing WIOA working procedure for groundwater quality assessment for drinking purpose  
Urban Hydrometeorology: an overview and bibliometric analysis of published research
Authors: Milošević Dragan , Teuling Ryan , Paparrizos Spyros , Steeneveld Gert-Jan
Published: March 2024

Urban hydrometeorological (UHM) research is important for managing the challenges that arise from the complex interactions between climate change, meteorological processes and the water cycle in urban environments. It provides valuable insights for sustainable urban development, infrastructure planning, climate change adaptation, public health and improving the overall resilience of cities to weather, water and climate-related challenges. This bibliometric research analyses published literature on the research topic of UHM. In total, 507 studies were assessed in the period 1975-2023 based on the Web of Science database, covering almost half of the century of UHM research. Three subperiods with different publication trends were noticed. The first publication subperiod is the longest (1975-2020), but with the fewest publications (45), while the second subperiod is substantially shorter (2011-2017), but with a significant increase in the number of publications (122). The third subperiod is the shortest, i.e., from 2018 to 2023, and it is characterized by further substantial increase in the number of publications (340); although the shortest, the third subperiod contains 67% of published UHM studies, thus showing the increased interest in this research topic during the recent years. Furthermore, majority of UHM studies were published in the research fields of: 1) Environmental Sciences (175 studies), 2) Water Resources (165 studies); and 3) Meteorology and Atmospheric Sciences (150 studies). Countries/regions leading the way in UHM research and publishing are the USA, China and England, while there is a noticeable lack of UHM studies from Global South. Regarding sustainable development, UHM studies mostly contributed to the research on SDG 13 (Climate Action), SDG 6 (Clean Water and Sanitation) and SDG 11 (Sustainable Cities and Communities). The keyword analysis further revealed the changes in the main research themes during the last decades of the 20th century and the first decades of the 21st century. This study can be beneficial for those interested in acquiring more knowledge about UHM research and its application.
The evolution of turbulence, stratification, and the surface jet in Diurnal Warm Layers
Authors: Miracca Lage Mariana , Ménesguen Claire , Merckelbach Lucas , Dräger-Dietel Julia , Griesel Alexa , Carpenter Jeff
Published: March 2024

The ocean's upper layer is inherently turbulent and constantly forced by momentum and buoyancy fluxes, and their interplay operates to mix and/or stratify the first meters of the water column. Incoming solar short-wave radiation acts to stabilize the upper layer, whereas the wind transfers momentum to the ocean and acts to vertically mix the water column. However, if the wind is not strong enough to trigger mixing, stratification in the near-surface is immediately formed in a layer of O(10) m thickness, called the diurnal warm layer (DWL). Above the bottom boundary of the DWL, shear production can be enhanced leading to large dissipation of turbulent kinetic energy (TKE) rates, i.e. high turbulence. Based on observational data from an ocean glider with a mounted microstructure package and drifters, we show the evolution of three DWLs sampled on the rim of a mesoscale eddy in the South Atlantic ocean (32oS, 4oE) with respect to temperature and buoyancy anomalies, potential energy and dissipation of TKE. In the near-surface, temperature and buoyancy anomalies increase with the evolution of the DWL, and the latter has the same magnitude as the time-integrated surface buoyancy flux. We also show the development of a diurnal jet with magnitude of O(10) cm/s that veers with the wind. Late in the afternoon, when the diurnal jet is fully developed, the bulk Richardson number (Rib) indicates that the stratified layer related to the DWL becomes marginally unstable (Rib ~ 0.25). During this period, the potential energy also decays, suggesting that the enhanced turbulence within the DWL acts to destroy stratiﬁcation through turbulent mixing. We further assess whether a one-dimensional turbulence model is able to reproduce the observed DWL’s characteristics and the change in stability throughout the day.
Segregation of thermochemical anomaly and associated deep mantle plume outside the large low-velocity provinces
Authors: Zhang Jie , Hu Jiashun
Published: March 2024

Plate tectonics plays a pivotal role in shaping the Earth's surface and is intricately linked to internal processes, including the subduction of cold slabs and the ascent of hot mantle plumes. Statistical analyses have unveiled a strong correlation between the distribution of large igneous provinces (LIPs) over the past 320 Ma and two large low-velocity provinces (LLVPs) beneath Africa and the Pacific Ocean. Consequently, hypotheses have emerged suggesting the long-term stability of these LLVPs. However, numerical modeling challenges this notion, suggesting that these basal mantle structures are mobile. To resolve these debates, we attempt to study these basal mantle structures from the evolution of intermediate-scale thermochemical anomalies. We report such an intermediate-scale thermochemical anomaly beneath the NW Pacific Ocean based on existing tomographic models and use paleogeographically constrained numerical models to study its evolution. Considering different plate configurations in North Pacific, our models consistently show that this anomaly was separated from the Perm anomaly by the subduction of the Izanagi slab in the Cretaceous. After the separation, it generated a mantle plume, inducing an oceanic plateau that got subducted beneath Kamchatka in Eocene. This scenario is consistent with multiple lines of evidence, including the seismic anomaly in the lower mantle, a seismically detected megameter-scale reflector that coincides with the subducted oceanic plateau and changes in Pacific Plate motion that correlated with the Eocene trench-plateau collision. We propose that intermediate-scale low velocity structures constantly undergo segregation and coalescing, and are sources of plumes that lie outside the two major LLVPs. Merging of the reported anomaly with the Pacific LLVP suggests the latter is still under assembly.
Labile components as geochemical tracers at the soil column-scale in permafrost peatlands
Authors: Perez-Serrano Lucia , Loiko Sergey , Artem Lim , Pokrovsky Oleg , Rols Jean-Luc
Published: March 2024

Permafrost peatlands constitute a reservoir of highly labile components such as dissolved organic carbon (DOC), macro- and micro-nutrients, and toxic elements. Fast thawing of permafrost peatlands in most of climate warming scenarios will lead to the mobilisation of dissolved components from soils to rivers and lakes. Permafrost peatlands situated in western Siberia are especially vulnerable to thawing, as they contain the largest soil water and ice resources in the northern hemisphere.  Half of the volume of ice resources is in form of dispersed ice on the soil top layer (0-3 m) [1]. Dispersed ice is enriched in dissolved components, which may be highly reactive and even provide sizable contributions to the hydrological system via suprapermafrost flow [2]. However, contributions from local soil column-scale in the context of micro-environments potential deepening of the active layer remain to be assessed.To characterize the dissolved fraction of dispersed peat ice, a study was performed in Tazovsky, a representative site located in a continuous permafrost zone in Siberia. Four peat cores (0-180 cm depth) were collected along a gradient from the bog to mineral-fen. DOC, nutrients and trace elements were analysed for both the porewater (active layer) and dispersed ice (frozen layer). Lateral and in-depth approaches were employed to quantify the pools of dissolved components. Preliminary results show an enrichment of highly labile components in the frozen layer, consistent with previous findings in the discontinuous permafrost zone [3]. We hypothesize that the highest concentrations of DOC and certain macro/micro-nutrients in the frozen layer are mostly driven by downwards colloidal migration during the freezing phase. These organic and inorganic nutrients may be released due to progressive thawing, and eventually become bioavailable for microbial uptake. Consequently, the production of CO2 may increase, contributing to the ongoing climate change.[1] W. H. Pollard and H. M. French, « A first approximation of the volume of ground ice, Richards Island, Pleistocene Mackenzie delta, Northwest Territories, Canada », Can. Geotech. J., vol. 17, no 4, p. 509-516, november 1980, doi: 10.1139/t80-059.[2] A. G. Lim et al., « Dispersed ground ice of permafrost peatlands: Potential unaccounted carbon, nutrient and metal sources », Chemosphere, vol. 266, p. 128953, march 2021, doi: 10.1016/j.chemosphere.2020.128953.[3] D. M. Kuzmina et al., « Dispersed ice of permafrost peatlands represents an important source of labile carboxylic acids, nutrients and metals », Geoderma, vol. 429, p. 116256, january 2023, doi: 10.1016/j.geoderma.2022.116256.
 Beyond Ambient Temperature: A Comparative Analysis of Heat Metrics for Detecting Heatwaves on a Country Level
Authors: Monthaler Tobias , Wieser Katharina , Brimicombe Chloe
Published: March 2024

Ambient temperature is the standard metric for the detection of heatwaves. However, when considering the impacts on humans the severity in terms of our wellbeing may be underestimated. The field of detecting human-perceived heatwaves is new and fast growing. It is important to recognise the difference in measuring heatwaves using heat metrics in comparison to the standard of ambient temperature. For this approach we develop an algorithm to track heatwaves on a country level through time for the last 30 years. Maximum daily temperature data is used in comparison to the heat metrics of WBGT and UTCI. Through all this, a substantiated knowledge basis should be established of how well the stated heat metrics are detecting heatwave impacts. The findings contribute to the development of standardized and robust approaches for utilizing reanalysis data in conjunction with heat indices, ultimately improving heatwave detection, forecasting and policy development.