bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating the maximum vegetation coverage and productivity capacity supported by rainwater resources on the Loess Plateau
Authors: Zhang Baoqing , Tian Lei , Li Yao
Published: March 2024

Large-scale revegetation presents a new set of challenges by augmenting water consumption in arid regions, despite its positive impact on ecosystems. In water-stressed areas, where precipitation is the primary source of water, extensive afforestation may disrupt the balance between water supply and demand. Consequently, it is crucial to assess the maximum extent of vegetation coverage and productivity that can be sustained by rainwater resources. Our study characterizes the sustainability of revegetation by determining the upper limit of the leaf area index (LAI) supported by rainwater resources. The research focuses on the Loess Plateau (LP), a region known for both large-scale vegetation restoration and severe water shortages. The upper limit on LAI is computed based on evapotranspiration (ET) supported by rainwater resources, utilizing an optimized Shuttleworth-Wallace (S-W) model that incorporates dynamic vegetation and carbon dioxide components. Carbon sequestration capacity and efficiency are compared between the maximum and actual vegetation scenarios using an analytical water use efficiency (WUE) model. Both models exhibit good performance and align with empirical observations. Results indicate that under the maximum vegetation scenario, the LAI is 11.5% higher than the actual scenario when vegetation on the LP is restored to its maximum level. The average gross primary productivity under the maximum vegetation scenario surpasses the actual scenario by 25.0%, with a 17.9% increase in ecosystem WUE. It is important to note that the maximum scenario represents a theoretical upper limit based on ideal assumptions. The findings emphasize that enhancing rainwater utilization efficiency can unlock the potential for sustainable vegetation restoration, improving its efficiency. This study provides valuable guidance and theoretical support for planning vegetation restoration in water-scarce regions.
Joint analysis of seismic velocity change, deformation and meteorological data for volcano monitoring
Authors: Dumont Quentin , Nishimura Takeshi , Hirose Takashi , Takano Tomoya
Published: March 2024

Detection of subtle precursors to forecast the timing and location of eruptive events are one of the main issues in volcanic risk mitigation. Seismic interferometry of ambient noise allows to detect very small change in the medium, but is affected by numerous processes such as strain and meteorological variations that need to be identified and characterized in order to correctly interpret the observation for operational monitoring. To assess the monitoring potential of the seismic velocity changes, we jointly analyzed 10 year time series of velocity, strain and meteorological changes at 21 Japanese volcanoes. They span different environmental conditions and volcanic behavior, insuring a broad sample of velocity–strain–environmental interactions.Daily seismic velocity changes were computed considering three frequency bands (0.5-1 Hz, 1-2 Hz and 2-4 Hz). Daily meteorological data were provided by the Japan Meteorological Agency (JMA). Deformation data include (1) areal strain computed from the GNSS stations of the JMA and Geonet network (from Geospatial Information Authority of Japan), and (2) numerically computed tidal strain by using GOTIC2 software (Matsumoto et al., 2001).We assumed the velocity change to results from the linear combination of the strain and meteorological changes (including rainfall, snow load, temperature, atmospheric pressure, wind speed and sea level variations), and inverted their respective contributions to the observed velocity variation using a least-squares method.Over the 21 volcanoes, the inversion of the parameters are able to explain 20-30% of the data in average. We determine that areal strain and temperature have, on average, a high impact on velocities (each representing ≈20% of the modeled velocities) but also shows a high variability from volcano to volcano, while pore pressure and sea level variations, which shows almost same amount of contribution to the velocities (≈20%), have a much lower variability indicating a background effect found at more or less all volcanoes. Atmospheric pressure and wind speed show similar behavior but at a lower level (≈10%). Snow have a relatively low impact over the whole year (≈5%) but it strongly increases during winter (up to 30%). Tidal strain do not demonstrate significant effect on daily velocity variations.In the details of each volcano, results demonstrate the possibility to retrieve the different component contributing to the measured velocity change. This shows encouraging results for several subsequent application such as: (1) detection of small eruptive precursor by removing the modeled contributions, (2) use of the velocity change as a stress monitoring proxy based on the determined strain sensitivity, (3) monitoring pore pressure change especially for lava dome stability. We also highlight the need for collocated seismic and meteorological sensors to achieve higher accuracy in the environmental effect correction.
A Comprehensive Analysis and Validation of the Modified TRIAD Approach in Soil Ecological Risk Assessment 
Authors: An Youn-Joo , Kim Dokyung , Kim Haemi , Lee Tae-Yang , Hyun Seunghun , Hong Sunhee , Jeong Seung-Woo
Published: March 2024

To protect and manage soil ecosystem from chemical pollution, the implementation of a site-specific soil ecological risk assessment is imperative. The TRIAD approach, endorsed by the International Standardization Organization, serves as a valuable tool for conducting site-specific assessments, integrating chemical, ecotoxicological, and ecological analyses. In Korea, efforts are underway to formulate guidelines based on the TRIAD methodology, organized into three key phases: desk study, TRIAD assessment, and risk management. The desk study phase reviews the need for a soil ecological risk assessment alongside a conceptual site model. If necessary, TRIAD assessments are initiated, considering screening and refined levels and socioeconomic factors. Following the determination of final risk values, a comprehensive risk management plan is created, involving monitoring and strategies such as removing or interrupting contamination sources. Case studies presented in this study demonstrate the adequacy and applicability of the proposed Korean guideline. The modified TRIAD technique and detailed toolbox introduced serve as valuable resources for efficient decision-making in protecting soil ecosystems in contaminated sites. Acknowledgement This work was supported by Korea Environment Industry & Technology Institute (KEITI) funded by Korea Ministry of Environment (MOE) 2022002450002 (RS-2022-KE002074).
Thermal conductivity of Fe-bearing bridgmanite and post-perovskite determined by machine learning
Authors: Wang Dong , Deng Xin , Wu Zhongqing
Published: March 2024

Bridgmanite (Brg) and post-perovskite (PPv), as the most abundant minerals at the lower mantle, could be the main minerals in the Large Low Shear Velocity Provinces (LLSVPs). However, their thermal conductivities, as well as the impact of Fe impurities, are highly controversial. Measuring the thermal conductivity of minerals at high P-T conditions remains challenging, and determining the thermal conductivity of minerals by first principles calculations leads to finite size effects due to computational limitations. To overcome computational limitations, we trained a machine learning potential for Fe-free and Fe-bearing Brg and PPv with data from first-principles calculations, then investigated their thermal conductivity at high P-T conditions based on the machine learning potential in the large cells with finite-size effects well considered. We found that the presence of 12.5 mol% Fe in the lowermost mantle decreases the thermal conductivities of Brg and PPv by 10% and 14%, respectively. Furthermore, the phase transition from Brg to PPv increases the thermal conductivity of pyrolite by 22%. Incorporating the distribution of minerals, temperature, and iron content obtained through the inversion based on mineral elasticity and seismic tomography models, we found the heat flux is significantly lower in the LLSVPs regions, which would have important implications for the geomagnetic field and the thermal evolution of the Earth.
Spatiotemporal patterns of water volume and total organic carbon concentration of agricultural reservoirs over South Korea
Authors: Lee Kwang-Hun , Kam Jonghun
Published: March 2024

Understanding the dynamics of organic carbon load in lakes and reservoirs is vital for comprehending the potential impact of human disturbance on the hydrological and carbon cycle. This study investigates the spatial and temporal variability of water volume and total organic carbon (TOC) concentration and examines changes in the TOC load during a drought year. We conducted a systematic analysis of water volume and TOC concentration data from 2,484 agricultural reservoirs in South Korea, covering 2020 to 2022 at both provincial and county levels. At the national level, the yearly TOC loads range between 1387 tons and1464.84 tons. This study conducts the rotated Principal Component Analysis (rPCA) of water volume and TOC concentration. The first rPCA mode showed a decreasing trend of water level (38% of the explained variance) and increasing trend of TOC concentration (23%) over the southern Korea region. The second rPCA mode is related to interannual variability of water level (23.5%) and TOC concentration (20%) over the central Korea region. In 2022, the southern and central Korea regions have a noticeable difference in water volume and TOC concentration. These variations were closely associated with a prolonged meteorological drought event in the southern Korea region, causing increased TOC levels and reduced water volume and thus changing a role of reservoirs from a carbon sink to a carbon source. This study provide insight about how organic carbon interacts with an extreme hydroclimatic condition in agricultural reservoirs.
Sand as a thermal energy storage material for solar thermal technologies
Authors: Radwan Omar , Humphrey John
Published: March 2024

Sand, an inexpensive and abundantly available natural geomaterial, holds promise as a thermal energy storage (TES) material in diverse solar thermal systems such as concentrated solar power, solar heating, and solar gasification. Sand possesses the ability to capture solar radiation during daylight hours, preserving it as heat on both a daily and seasonal basis, and then releasing it when demand is high. Although sand exhibits lower thermal conductivity and specific heat capacity when compared to molten salt and engineered TES materials, it compensates for these drawbacks by withstanding high temperatures and being economically advantageous.For sand to effectively function as a TES medium, it needs to acquire a high energy density. This entails a considerable specific heat capacity and resilience to substantial temperature variations. Optimal for this purpose, pure quartz sand stands out due to its elevated specific heat capacity, high thermal conductivity, and its ability to maintain integrity without agglomerating or degrading even at temperatures exceeding 1000°C. Impurities adversely affect the energy density of sand. The presence of clays, carbonates, and feldspars has been identified as leading to premature agglomeration, early degradation, and/or reduced specific heat capacity in sands. At a temperature of 600°C, clays were observed to enhance the tendency of sand to agglomerate, with agglomeration increasing with rising temperature and pressure. Below 800°C, carbonate minerals undergo decarbonization, resulting in mass loss and alterations in grain-size distribution. For instance, calcite grains transform into lime powder, which exhibits an extremely low specific heat capacity. Below 1200°C, feldspars undergo vitrification, leading to agglomeration that hinders fluidization and the flow of sand through the system. To avoid these complications, it is imperative to limit impurities to less than 2%.
The morphological disparity, ecological evolution and palaeobiogeography of Palaeozoic hyoliths
Authors: Liu Fan , Topper Timothy P , Strotz Luke C , Liang Yue , Hu Yazhou , Skovsted Christian B , Zhang Zhifei
Published: March 2024

Hyolitha is a group of extinct invertebrates, the most dominant benthic animals within the Cambrian evolutionary fauna, forming part of the Palaeozoic evolutionary fauna. Hyoliths are generally divided into two groups, Orthothecida and Hyolithida. They originated in the Terreneuvian and experienced a rapid diversification during the Cambrian Explosion but reached a diversity bottleneck during the Cambrian extinction (Sinsk Event). Hyoliths were characterised by low disparity beginning from the Ordovician and got extinct in the Permian. Factors that affected the evolutionary pattern of Palaeozoic hyoliths from the early domination period up to extinction are poorly known. Herein, we collected material on 148 Palaeozoic hyolith genera from around the world and documented their key morphological characters and distributions. Combined with the phylogenetic analysis based on a matrix of morphological characters, the nonmetric multidimensional scaling (NMDS) using the Paleontological Statistics Software Package, and palaeobiogeographical data, we intended to analyse the biodiversity changes during the evolutionary history of hyoliths and uncover the influence of morphological selectivity in different palaeoenvironments, from the Cambrian to the Permian.Our results showed that the Cambrian taxa occupied quite a different morphospace compared to that of the Ordovician-Permian assemblages. The morphology of the early Cambrian hyoliths was mainly simple, comprising long conical weakly ornamented tubes. They radiated worldwide during the Cambrian ‘Epoch 2’, reaching high disparity and diversity, but faced a disadvantageous situation after the mid-Cambrian. The younger genera with strong ornamentation usually showed low diversity and provincialism during the Ordovician. The morphological shift from a simple conical tube morphology with weak ornamentation (orthothecids of the early Cambrian) to a complex morphology with distinct venter and dorsal pyramidal conch and strong ornamentation from the late Cambrian up to the Permian reflects ecological evolution of the hyoliths. This was accompanied by a change of their feeding habits from active deposit-feeding to passive suspension/filter feeding and a change in conch configuration from rheophilic to non-rheophilic.
Effects of Different Micro-Irrigation Methods on Water Use and the Economic Benefits of an Apple–Soybean Intercropping System
Authors: Dai Houshuai , Wang Ruoshui , Chen Li , Wang Lisha , Wang Xin , Xiong Chang , Zhang Meng
Published: March 2024

Intercropping systems reduce ineffective evaporation between trees but also intensify interspecific competition and reduce productivity. To improve the water-use efficiency and the economic benefits of an intercropping system on the Loess Plateau, China, where rainfall is limited and evaporation intense, an apple–soybean intercropping system with micro-irrigation water control was adopted to analyze the soil water, root density, water-use efficiency, yield, and economic benefits of intercropping under different micro-irrigation methods. Subsurface seepage irrigation, bubbler irrigation, and drip irrigation under mulching were used with irrigation upper limit levels of three maximum irrigation levels [60% (W1), 75% (W2), and 90% (W3) of field capacity (FC)]. Rainwater harvesting from ridges and furrows (GL) without irrigation was the control. Bubbler irrigation increased the soil water content, optimized the vertical soil water distribution, and promoted root growth. Except for the control treatment (GL), the other micro-irrigation treatments increased with the irrigation amount, but the water-use efficiency decreased. Drip irrigation under mulch combined with W2 (75%Fc) irrigation could obtain the maximum intercropping yield, which was increased by 71.1% compared with the GL treatment. Drip irrigation under a mulch combined with W2 produced the maximum intercropping yield; the economic benefits were higher under drip irrigation with mulching combined with W1; and all three micro-irrigation methods combined with W2 improved the economic benefits by 52.1–115.5% compared to GL. Drip irrigation under mulching or bubbler irrigation combined with W2 should be used when there are sufficient water resources, but drip irrigation under a mulch combined with W1 when there is a water shortage.
Air-Water Exchange of Xenoestrogen in Surface Water in Suzhou of China and the Health Assessment
Authors: Wang Minhao , Li Dongling , Tong Ting , Wang Fang , Chen Kui , Zhang Haifei , Han Lei
Published: March 2024

Endocrine disruptors are widely present in the environment and are defined as a subset of endocrine disruptors due to the biological activity of environmental estrogens (xenoestrogens). These substances persist as trace environmental pollutants and contribute to the material cycle. Atmospheric transportation is regarded as the main source of xenoestrogens in inland lakes. However, previous research on the air-water exchange of ecological estrogens in freshwaters has been limited, and studies have indicated that sex differences may result in heterogeneity in the health effects of the same air pollutants. Consequently, this study aims to access the interface exchange process of selected xenoestrogens and the health risks associated with non-dietary exposure in adults.The results showed significant differences in the direction of air-water exchange for various exogenous estrogens. The air-water exchange rate of dibutyl phthalate is closely correlated with temperature and humidity. Discrepancies in melting point and water solubility of other exogenous estrogens may contribute to differences in exchange rate. Moreover, the non-dietary intake of health hazards posed by six environmental estrogens in atmospheric fine particulate matter is within acceptable limits (Total Health Risk < 1). Among these, dioctyl phthalate, identified as a potential carcinogenic pollutant, also falls within an acceptable level of carcinogenic risk (
GAIN, a Machine Learning approach for Airborne, Maritime, and Submarine Gravimeter Systems
Authors: Iafolla Lorenzo , Chiappini Massimo , Santoli Francesco
Published: March 2024

Precision gravimeters deployed onboard aerial, groundbased, and underwater moving platforms face significant accuracy challenges due to environmental disturbances such as non-inertial reference systems and temperature variations. The “Gravimetro Aereo INtelligente” (GAIN) concept represents a step forward in tackling this problem by using a data post-processing approach. This approach avoids cumbersome, heavy, and power-intensive active compensation systems, thus increasing the instrument's adaptability to small moving platforms.The GAIN concept is based on three pillars that define its approach. Firstly, it incorporates a multi-sensor system within the gravimeter framework, which might include a three-axial accelerometer, a three-axial gyroscope, multiple thermometers and a barometer. This set of sensors are designed to measure both the effects of gravity and of other disturbances. By utilizing this information, GAIN employs machine learning algorithms (the second pillar) to map the complex relationship between the measurements and the desired gravity value. However, machine learning heavily relies on the availability of high-quality training datasets, which are often scarce and challenging to obtain in operational environments. To address this bottleneck, the third pillar of GAIN utilizes a training platform that can simulate a wide range of environmental situations in a controlled laboratory setting. This platform enables the generation of labeled data that mimics real-world operational scenarios.This contribution will present the details of the initial GAIN experimental setup, highlighting the successful integration of a multi-sensor system with the training platform. Additionally, early findings will be shared, demonstrating the potential of the GAIN technique in mitigating temperature changes in gravimeters. Finally, the progress of ongoing experiments will be showcased, as we work towards expanding the capabilities of the GAIN method to also address rotations and linear accelerations as sources of interference.
Control of salt tectonics on the hydrocarbon traps development: the surrounding structures of the Qom Kuh, Central Iran
Authors: Nikpoush Sadaf , Soleimany Bahman
Published: March 2024

Salt tectonics and salt structures are attractive targets for hydrocarbon exploration since salt-related deformation can form hydrocarbon traps and influence hydrocarbon migration. Salt diapirs are considered a suitable site for reserving natural oil/gas, landfills, and hazardous wastes. Determination of the origin and age of salt diapirs, the diapir formation and evolution model, and their impacts on the surrounding structures are very necessary for hydrocarbon exploration. To characterize the structural and tectono-sedimentary evolution of the salt diapir at the Qom Kuh, located in the Qom basin (Central Iran), this research describes the origin, timing, and evolution history of the salt structure through the tectono-sedimentary analysis and field study. Moreover, the effect of salt diapirism on the surrounding structures is investigated in the study area. The results obtained from the interpretation of seismic profiles and the investigation of the geometry of the sedimentary layers across the growth salt structure indicate that the salt extrusion occurred during two stages in the Qom Kuh. According to the structural evidence (e.g., hook and cusp) and the tectonic-sedimentary analysis, the first stage of salt extrusion happened in the Early Miocene concurrently with the extensional deformation event from the Eocene to the Early Miocene in the study area. The second stage of salt diapirism and its extrusion occurred during multi-stages of the Zagros orogenic compression from the Late Miocene to the present day. The final geometry of the salt diapir at the Qom Kuh formed along a releasing bend that was created by dextral transpressional strike-slip fault activity during the Zagros orogeny. Based on the lower thickness of evaporite units in the Upper Red Formation (Early Miocene) compared to the Lower Red Formation (Early Oligocene) and observing fragments of the Eocene volcanic rocks in the extruded salt on the ground surface, the Lower Red Formation salt along with the Upper Red Formation evaporites considered as the main source of salt diapirism in the Qom Kuh. Salt diapirism affected the surrounding structures of the Qom Kuh such as the Western Kuh-e-Namak and Western Alborz anticlines. The fold geometry and the hydrocarbon trap development in the Western Kuh-e-Namak and Western Alborz fields are controlled by salt tectonics and the occurrence of inversion tectonics. The results of this study could add data to worldwide examples of the impact of salt tectonics on the hydrocarbon trap development in collisional orogenic belts.
Keywords: Salt tectonics; Tectono-sedimentary analysis; Hydrocarbon traps; Qom Kuh; Central Iran
Greening fails to translate into an increase in Net Primary Productivity due to warming constraints in India
Authors: Das Ripan , Chaturvedi Rajiv Kumar , Roy Adrija , Karmakar Subhankar , Ghosh Subimal
Published: March 2024

India has made the second-largest contribution to global greening in the last two decades. However, it is not clear whether this greening has led to an overall increase in net primary productivity and hence carbon uptake potential, given the impact of climate change on vegetation. In this study, using MODIS satellite data for the period 2001–2019, we attempt to find out the extent to which increased greening in India has led to an overall increase in primary productivity in recent decades. Despite a statistically significant increase in the Leaf Area Index (LAI), we found a slightly decreasing trend (not statistically significant) in Net Primary Productivity (NPP) and stable Gross Primary Productivity (GPP) during the 21st century. Our analysis also shows that the NPP of temporally consistent Indian forests shows a significant decreasing trend despite the increase in LAI. Notably, there are spatial differences in the NPP trend, with the regions contributing the most to NPP in India showing a stronger decreasing trend. The regions with a significantly decreasing NPP trend also experienced the strongest warming during the study period. We also used the nonlinear kernel regression method to investigate the temperature response of vegetation productivity in these regions. We observed that photosynthesis in these regions decreased above a certain temperature and respiration became stable, leading to a decrease in NPP. Our analysis shows that climate change, especially the rise in temperature, has already begun to affect vegetation productivity and carbon uptake in Indian forests. The study also conveys the clear scientific message that increased greening does not necessarily lead to increased carbon uptake, especially in a country like India where agriculture is intensifying. This analysis also has significant implications for the scientific analysis of planning to achieve India's net zero emissions pledge by 2070.
Long-term palaeoecological trends of the Late Cretaceous bivalves from Ariyalur, India
Authors: Mukhopadhyay Arkaprava , Paul Shubhabrata , Poddar Arghya , Chattopadhyay Debarati , Saha Ranita
Published: March 2024

The present study aims to investigate the change in the bivalve community in the Late Cretaceous of the Ariyalur Sub-basin, south India, along with the changing sea level, depositional sequence, and lithology. A drop in bivalve diversity was recognized from the siliciclastic facies of the Coniacian-Santonian to the carbonate facies of the Maastrichtian. Two-way cluster analysis identified five distinct bio-assemblages and a prominent shift in the dominant ecological guild. The Coniacian–Santonian assemblages are dominated by infaunal taxa that changed into epifaunal-dominated Maastrichtian assemblages. Although the effect of secondary diagenetic alteration might have played a role, non-metric multidimensional studies suggest that other factors, especially the change in substrate condition and corresponding adaptive strategies employed by different functional groups of bivalves, may potentially explain the shift in community structure across the studied interval.
Suprathermal Ion Acceleration at the Near-Sun Heliospheric Current Sheet Crossings observed by Parker Solar Probe During Encounters 7-15
Authors: Desai Mihir ,   Parker Solar Probe, ISOIS, FIELDS, and SWEAP Science TE]tams
Published: March 2024

We report observations of time-intensity profiles, velocity dispersion, pitch-angle distributions, spectral forms, and maximum energies of 10:1 sunward flow of the accelerated ST ions. We present detailed analysis of the evolution of the pitch-angle distributions and spectral properties during this crossing which have revealed, for the first time, important clues about the nature of ion acceleration via reconnection-driven mechanisms at the near-Sun HCS.
An Observational Analysis of the Evolution and Structures of an Extreme Wind Gust Event in East China
Authors: Chen Tianmeng
Published: March 2024

This study examines an extreme wind gust event of over 45 m s-1 occurring in the Yangtze River Delta (YRD) in East China on 30 April 2021, which broke the historical record of surface wind speeds of 221 automated weather stations. A high-resolution mesonet of eight radar wind profilers (RWPs) and six triangular regions along the path of the propagating wind gust is utilized to investigate the dynamics of the extreme wind gust event. Downward transport of turbulence and momentum, and the changes in vertical divergence and vorticity distributions during the event are analyzed. Downward momentum transport likely contributes to the formation of a gust front, and the combination of a gust front and a mesocyclone is of significance in the formation of the extreme wind gust in addition to the large-scale environment. Intensification in mesoscale circulation produced by the merging process likely results in new convection initiation, which potentially accelerates the surface wind through intensified wind shear, and ultimately resulting in the occurrence of the extreme wind gust. This study highlights the role of multiscale processes in the formation of extreme wind gust, as well as the advantage of the non-negligible capability of RWP mesonet in monitoring the turbulence and momentum transport during the passage of the extreme wind systems. The RWP mesonet can serve as a good entry point in extreme wind nowcasting and prediction studies in the future.
First results about height correction of tropospheric delay mapping function in GNSS applications
Authors: Wang Miaomiao , Li Ping , Lu Ruyu , Wang Shuheng , Zhang Fangyu
Published: March 2024

One of the dominant error sources for Global Navigation Satellite System (GNSS) measurements is the correction for delay of an electromagnetic wave as it traverses the neutral atmosphere, which is usually shorted as tropospheric delay. Generally, tropospheric delay must be calculated or estimated since refractivity along ray path is not easily or economically measured. Empirically, the line of sight delay for either hydrostatic or wet component is modeled as product of zenith delay and a mapping function. The accuracy of estimated geodetic parameters for GNSS could be limited due to the indeterminacy of mapping function, when observations are typically made to low elevation angles. Nowadays, there are many different empirical tropospheric delay mapping functions are generated and used in GNSS applications, the sensitivity of mapping functions to height above the geoid of point of observations are mostly corrected with method and formulas proposed in Niell (1996), in which the height corrections are only concerned in hydrostatic delay mapping function. In Niell (1996), the adopted form of height correction for hydrostatic delay mapping function is linearly dependent on height, and the linear coefficient is empirically chosen for fitting precision purpose. In this work, similar to many current works about modelling mapping factors to operational mapping functions, with the help of ERA-Interim reanalysis data set from the European Centre for Medium-range Weather Forecasts (ECMWF), the sensitivity of both hydrostatic and wet delay mapping factors to height are calculated and preliminary analyzed. As an important part of the work, the needed data set sources, i.e., the tropospheric delays at some ground-based stations along some previously set ray paths with different elevation angles, azimuth angles, heights and time epochs, are generated with a self-generated tropospheric delay ray-tracing package named GTRATS (Gnss Tropospheric delay RAy Tracing Software). The first results show that for a specific not low elevation angle, the variations of both hydrostatic and wet mapping factors to the height are not too obvious; the hydrostatic mapping factors change linearly to height with different performances, while wet mapping factors are not with linearly change, especially for low elevation angles; height corrections with method in Niell (1996) for hydrostatic mapping factors actually perform well in some cases, while maybe correct too much or too less in some stations at some time epochs, thus maybe new correction strategy can be accounted; the height correction should also be concerned for wet delay mapping functions, while there is no obvious, regular and reliable relation or appearance can be observed according to our first results, and more efforts should be made for the examination and investigation of this problem.
A framework for the super attribution of multiple extreme events
Authors: Lu Chen , Coppola Erika , Pichelli Emanuela , Faranda Davide
Published: March 2024

Detection and attribution of anthropogenic influence on extreme events has always been one of the focuses of climate research. A number of studies have been undertaken that employed different approaches (such as the risk-based, Boulder, and circulation-based ones) for attributing individual extreme events of various types over the globe. While many of these extreme events are attributable to anthropogenic or natural factors, some still remain inconclusive. To this end, a super attribution framework is proposed, in which multiple extreme events occurring in one region within a predefined timeframe are considered as a whole instead of individually. The rationale is that climate change may influence large-scale circulation over a region, which subsequently alters the frequency of extreme events in multiple locations in this area. Specifically, the supervariable is proposed to characterize how severely a region is affected by extreme precipitation in terms of area. It is defined as the fraction of area in a region that experiences extreme precipitation of over 99.9th percentile in each day. The trends in the supervariable in the 20 Italian regions are examined. For regions with positive but not significant trends, there could be an anthropogenic signal present, but it could be too weak to be detected. Therefore, regions with positive trends are selected, and a super attribution is undertaken on them simultaneously. It is accomplished by calculating the combined supervariable, which is obtained by pooling the stations/grids of the selected regions together. Simultaneous events that occur in the autumn of each year are then considered. The results show that a statistically significant increasing trend can be identified in the combined supervariable for the selected regions, which suggests an increase in the area affected by extreme precipitation. In parallel to the statistical analysis, dynamical attribution is also carried out using the analog method, and the type of pattern that is both significantly influenced by climate change and associated with significant increases in precipitation is identified.
A synoptic circulation patterns evaluation framework for CMIP6 GCMs over the Euro-Mediterranean region
Authors: Olmo Matias , Campos Diego , Pep Cos , Ángel Muñoz , Albert Soret , Francisco Doblas-Reyes
Published: March 2024

In a global warming scenario, there is a growing need to understand why the Euro-Mediterranean region is a hotspot for both warming and drying signals and the seasonal and regional details, thus providing improved climate information required by decision makers. This work focuses on the design of an evaluation framework for climate simulations based on a classification of synoptic circulation patterns (CPs). A set of 30 CMIP6 global climate models (GCMs) is evaluated in terms of how well they reproduce the spatio-temporal variability of a CPs classification within the region. CPs are constructed through a hierarchical clustering procedure, using daily mean sea level pressure (SLP) during 1950-2014 against the ERA5 reanalysis. The link with surface variables -including precipitation, minimum and maximum temperatures- is also studied. Model performance is quantified based on different metrics for the spatial and temporal representation of the SLP patterns and the associated surface conditions, allowing a ranking of the best-performing GCMs.GCMs adequately reproduce the annual cycle of the CPs frequency, with a dominant synoptic structure during summertime enhancing warm and dry conditions. Best-performing models in this regard include MPI-ESM1-2-LR, EC-Earth3-CC and MRI-ESM2-0. However, the correct timing of this CP and the transitional patterns are often misrepresented, such as in GFDL-ESM4 and NorESM2-LM. The analysis of the surface patterns associated with each CP show good model skills, better for the extreme temperatures than for rainfall and particularly during the transition seasons, for which the GCMs spread also increases. In this sense, the models EC-Earth3-Veg, EC-Earth3-CC and GFDL-CM4 present the best scores, whereas INM-CM5-0, KIOT-ESM and NorESM2-LM show the lower skills. By blending both the spatial and temporal features of the CPs, the EC-Earth3-CC, EC-Earth3-Veg, GFDL-CM4 and MRI-ESM2-0 arise as the best-performing GCMs over the Euro-Mediterranean region.Overall, it is highlighted that not all models perform best in all the aspects considered, emphasizing the need of a complete process-based model evaluation. This is a way to constrain the future projections in order to reduce uncertainty and come up with coherent climate information at a regional scale.
Banana Current in the Inner Magnetosphere Observed by Van Allen Probes
Authors: Zhang Xiao-Xin , Wang Tonghui , He Fei , Lv Jingtian , Zong Qiugang , Fu Huishan
Published: March 2024

By using the magnetic field data from Van Allen Probes, we analyzed the distribution characteristics of the electromagnetic environment in the inner magnetosphere on different Dst* index and magnetic local time. Our results show that for the response of different current systems, the dawn-dusk and noon-midnight asymmetry distribution of the residual magnetic field δB increases with Dst* index. When Dst* < −60 nT, a “banana”-shaped geomagnetic field negative disturbance peak region appears in the sector from midnight to dusk. Then, we obtained the azimuthal current density and found the asymmetric internal eastward and external westward ring current. Through the vector analysis of three-dimensional current density, the current density vector distribution in the magnetic equatorial plane is completely displayed for the first time, which directly proves the existence of banana current near r = 3.0–4.0 RE during strong geomagnetic storms.
Quantifying dendritic crystallization in hydrous basaltic magmas through 4D experiments with in situ view: implications for magma mobility within the Earth’s crust
Authors: Arzilli Fabio , Polacci Margherita , La Spina Giuseppe , Le Gall Nolwenn , Llewellin Edward W. , Brooker Richard A. , Torres-Orozco Rafael , Di Genova Danilo , Neave David A. , Hartley Margaret E. , Mader Heidy M. , Giordano Daniele , Atwood Robert , Lee Peter D. , Burton Mike R.
Published: March 2024

The mobility and the rheological behaviour of magma within the Earth’s crust is controlled by magma viscosity. Crystallization and crystal morphology strongly affect viscosity, and thus mobility and eruptibility of magma, by locking it at depth or enabling its ascent towards the surface. However, the relationships between crystallinity, rheology and eruptibility remain uncertain because it is difficult to observe dynamic magma crystallization in real time.Here we show the results of in situ 3D time-dependent, high temperature, moderate pressure experiments performed under water-saturated conditions to investigate crystallization kinetics in a basaltic magma. 4D crystallization experiments with in situ view were performed using synchrotron X-ray microtomography, which provides unique quantitative information on the growth kinetics and textural evolution of pyroxene crystallization in basaltic magmas.  Crystallization kinetics obtained with 4D experiments were combined with a numerical model to investigate the impact of rapid dendritic crystallization on basaltic dike propagation, and demonstrate its dramatic effect on magma mobility and eruptibility.We observe dendritic growth of pyroxene on initially euhedral cores, and a sur- prisingly rapid increase in crystal fraction and aspect ratio at undercooling ≥30 °C. Rapid dendritic crystallization favours a rheological transition from Newtonian to non-Newtonian behaviour within minutes. Modelling results show that dendritic crystallization at moderate undercooling (30-50 °C) can strongly affect magma rheology during magma ascent within a dike with important implications for the mobility of basaltic magmas within the crust. Our results provide insights into the processes that control whether magma ascent within the crust leads to eruption or not.
Middle Miocene integrated stratigraphy, paleoclimatic and environmental turnover imprints from the Kurdistan Foreland Basin, N. Iraq.
Authors: Ameen1 Fadhil , Koshnaw Renas , Vassilyan Davit
Published: March 2024

Integrated stratigraphic and sedimentological analysis have been used to reconstruct the paleoclimatic and paleoenvironmental history of the nonmarine siliciclastic deposits of the Injana Formation (Langhian-Serravallian) from the Kurdistan foreland basin (N. Iraq).The transition from marine to nonmarine deposits resulted from the gradual retreat of the Neotethys seaway SE-ward, sea level change, and the rising of the Zagros Fold-Thrust Belt. The last marine foreland deposits (Consist of mixed lagoonal carbonates and evaporites) of the Fatha Formation (Burdigalian) vary from the predominated nonmarine fluvial deposits of the Injana Formation siliciclastic deposits (with predominated sandstone, mudstone, and claystone). Bioevents variations are evident in benthic foraminiferal (Ammonia beccarii, miliolides). The marine mollusca represent by pelecypods and gastropods (i.e.,   Ostrea latimarginata , Ostrea subangulata, Clausinella persica, Clementia sp.,Cardium spp, Acteocina spp, Turbo sp.). The ichnofossil assemblages also shows varation from predominated Planolites, Thalassinoides  to Skolithos   and Scoyenia . The freshwater ostracods (Cytheridella, Penthesilenula) and brackish” water ostracods (i.e., Cyprideis) have been recorded in non -marine sequences while Chrysocythere spp, are predominated in the lagoonal parasequences.  Although Miocene mammals are rarely found in the Kurdistan foreland basin, recently, new terrestrial vertebrate remains were discovered, confirming the transition from marine to nonmarine depositional environments. This transition was associated with climate change from the warmest condition of the middle Miocene climate optimum (MMCO) to a colder condition. In addition, the XRD results indicate that clay mineralogy is changing, as illite-chlorite assemblages are replaced by bentonite-montmorillonite clays. The XRF results indicate the predominance of iron and silica oxides in the nonmarine deposits, whereas calcium, magnesium, sulfur oxides, and alkalis characterize the earlier marine deposits. These new results, in addition to the discovery of terrestrial vertebrate remains and the rise of the Zagros Mountains, show that the middle-late Miocene time was a critical period in shaping the present-day habitat in the NW Zagros belt.
The safe operating spaces for grazing in China’s drylands
Authors: Li Changjia , Fu Bojie , Wang Shuai , Stringer Lindsay , Zhou Wenxin , Ren Zhuobing
Published: March 2024

Degradation of ecosystems can occur when certain ecological thresholds are passed below which ecosystem responses remain within ‘safe ecological limits’. Ecosystems such as drylands are sensitive to both aridification and grazing, but the combined effects of such factors on the emergence of ecological thresholds beyond which ecosystem degradation occurs has yet to be quantitatively evaluated. This limits our understanding on ‘safe operating spaces’ for grazing, the main land use in drylands worldwide. Here we assessed how 20 structural and functional ecosystem attributes respond to joint changes in aridity and grazing pressure across China´s drylands. Gradual increases in aridity resulted in abrupt decreases in productivity, soil fertility and plant richness. Rising grazing pressures lowered such aridity thresholds for most ecosystem variables, thus showing how ecological thresholds can be amplified by the joint effects of these two factors. We found that 44.4% of China’s drylands are unsuitable for grazing due to climate change-induced aridification, a percentage that may increase to 50.8% by 2100. Of current dryland grazing areas, 8.9% exceeded their maximum allowable grazing pressure. Our findings provide important insights into the relationship between aridity and optimal grazing pressure and identify safe operating spaces for grazing across China’s drylands.
Probabilistic Assessment of Slip Rates Over Time of OffshoreBuried Thrusts: A Case Study in the Central Adriatic Sea(Italy)
Authors: De Matteo Ada , Barrera Daniel , Maesano Francesco , Toscani Giovanni , Seno Silvio , Basili Roberto
Published: March 2024

Understanding the recent tectonic activity and seismotectonics of inaccessible buried faults requires the development of feasible and robust approaches. The foredeep deposits of the northern and central Apennines (an offshore area in the central Adriatic Sea, Italy) blanket the active buried frontal thrusts of the Apennines and the Dinarides orogens. Detecting recent-to-ongoing tectonic activity of these thrusts is particularly challenging because sedimentation rates easily exceed the very slow tectonic rates.In this work, we combine seismic reflection profile interpretation, sediment decompaction, kinematic restoration and balancing to quantitatively analyse the Plio-Pleistocene tectonic activity of the Apennines and Dinarides buried thrusts in the central Adriatic Sea and calculate the slip rates of the major faults. The northern and central Apennines foredeep is filled by a thick Messinian to Quaternary sedimentary wedge, unconformably resting on a Meso- Cenozoic carbonatic and siliciclastic passive margin succession, which is in turn involved in the east-northeast propagation of the fold-and-thrust belt from onshore to offshore (Adriatic Sea). As suggested by previous studies, the region is in a substantial tectonic activity decrease, but local and qualitative observations on specific structures show evidence of recent tectonic activity. The frontal thrusts of both the Apennines and the Dinarides are active, as also demonstrated by the moderate seismic activity historically (few past centuries) recorded in the region and by the recent earthquakes, followed by rather rich aftershock sequences that occurred in this region and nearby (e.g. the Porto San Giorgio earthquake Ml 5.0 in 1987; the Jabuka earthquake Mw 5.5 in 2003, the Pesaro earthquake Ml 5.7 in 2022). We interpreted, depth converted, and restored two northeast-trending regional seismic reflection profiles, thus roughly orthogonal to the main strike of the buried thrusts. We then used the inverse trishear approach to determine the slip necessary to recover the residual tectonic deformation (after decompaction) of four stratigraphic horizons with well-constrained age determinations (Zanclean to Middle Pleistocene). We then calculated and reported the slip rates using probability density functions, considering the uncertainties associated with both horizon ages and the restoration process. All together, our results show a progressive reduction of slip rates over time, with a main slowdown around 1.5 Ma. Reporting slip rates with probabilistic distributions is useful for incorporating epistemic uncertainty on the total seismic moment release in earthquake hazard analyses.
Highly collisional regions determined by interplanetary magnetic field structures
Authors: Lai Hairong , Pan Lin , Jia Yingdong , Russell Christopher , Connors Martin , Cui Jun
Published: March 2024

Submicron debris released in interplanetary collisions gets charged in the solar wind and generates disturbances to the magnetic field environment. The unique magnetic field disturbances, named interplanetary field enhancements (IFEs) are recorded by many spacecraft. In this study, we have developed a novel model to trace the IFEs to their origins. By employing this model, we can pinout regions with highly collision frequencies, thereby identifying regions of intense collisional activity. We can also determine the long-term variation of these highly collisional regions with interplanetary magnetic field observations over decades. The model can help constrain interplanetary magnetic disturbances and our results can be used to guide part of the interplanetary-object survey.