bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-dimensional shallow velocity structure beneath the urban agglomerations revealed by methane source and dense array
Authors: Zhang Yunpeng , Wang Liwei , Wang Weitao , Liu Shishuo , Ye Xiuwei , Yang Wei , Xu Shanhui , Ma Xiaona
Published: March 2024

The three-dimensional (3D) velocity structure beneath urban agglomerations is an important data for urban construction planning and earthquake hazard risk assessment. Combining a short-period dense array with the active source can enable us to conduct high-resolution imaging of shallow structures, with a short observation time. With the increasing limitations on the usage of explosives, we have developed a new type of active source, the methane source, which has been proven to be environmentally friendly, efficient, safe, and economical. It produces seismic waves by rapidly releasing high-pressure air in borehole by igniting oxygen and methane with the reaction products of carbon dioxide and water, and can be applied to various complex terrains to detect small-scale subsurface structures, particularly in cities and fault zones.To obtain the high-resolution structure beneath the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), we deployed a dense array consisting of 6,172 short-period stations, and carried out 63 active source excitations using new methane green sources in 2020. Using the manually picked 16,885 first-arrival phases from 63-shots methane sources, we present the first high-resolution 3D shallow P-wave velocity structure (above 1.5 km depth) in the central area of the GBA. The obtained results show that (1) the velocity images have a good correspondence with the regional topography and shallow lithology distribution. The depression area presents a low Vp distribution, while the uplift area with high Vp anomalies, which corresponds to clastic sedimentary rocks, granites, and metamorphic rocks, respectively. (2) The velocities have a strong anomaly on both sides of the Guangcong fault, Shougouling fault, Zhujiangkou fault, and Baini-Shawan fault. Among them, the Shougouling fault has the strongest controlling effect, making the velocity images show obvious differences between the north and south side along the fault at different depths. (3) The cross-fault velocity profiles show that regional faults control the distribution and burial depth of sedimentary layers. Our study shows that combination using of new green methane source and dense short-period array is an effective method to detect the shallow velocity structure and fault system under urban agglomerations.
Functional biogeography integration in a land surface model: Spatial trait variability impact on productivity and stability of permanent grasslands in France
Authors: Chebbo Sara
Published: March 2024

Biodiversity and associated functional diversity are expected to improve ecosystem stability in response to climate change. Land surface models (LSMs), such as Dynamic Global Vegetation Models (DGVMs), currently represent each plant functional type (PFT) as a "mean" plant, characterized by a set of global-scale average parameters that are static in space and time. However, this approach neglects to consider the diversity of traits observed in natural populations. To address this limitation, we incorporated the functional biogeography in the ORCHIDEE model, one of the most known DGVMs.  In this study, we aim to refine the representation of trait-based models to better capture the complexity of natural ecosystems.We used a 5 km map of French permanent grasslands (FPGs) generated as part of the DIVGRASS project.  In this study, we focused on the case of FPGs for the 1960-2019 period. First, trait data were collected, and the distribution of traits was analysed at the national scale in France. The primary objective is to introduce the concept of Community-Weighted Means (CWM) of two key traits,  namely the specific leaf area (SLA) and the maximum rate of carboxylation (VCMAX) to better capture trait diversity within communities. We calculated the leaf lifespan (LLS), one of the traits represented in the model by a constant value. Five different experiments were performed using the ORCHIDEE model in order to simulate the net primary productivity (NPP) in each scenario. Furthermore, this study emphasizes the need to examine not only the productivity of grasslands in France but also the stability of grassland productivity. The choice of which stability productivity component to consider is pivotal for understanding the ecosystem functioning. Thus, we focused on the temporal invariability (constancy) and the maximum deviation from the average level of functioning baseline (resistance) of grassland productivity over time. Subsequently, we established relationships between productivity, constancy and resistance when all grasslands are combined on one hand and across four distinct grassland habitats with a contrasting floristic composition on another hand.  Finally, we used the satellite observations to assess the spatial similarity with the simulated NPP by the ORCHIDEE model in each of the 5 experimental cases. This study underscores the importance of incorporating community-weighted metrics and trait diversity in order to enhance the ecological relevance and accuracy of DGVMs. Understanding how trait values affect productivity and its stability is vital, especially when considering land surface models such as ORCHIDEE.  Keywords:  C3 permanent grasslands, functional biogeography, biodiversity, ecoinformatics, land surface model,  plant traits, community weighted mean, constancy, resistance, dynamic global vegetation model, ORCHIDEE model, productivity, climate change, satellite observations 
Complexity, Connectivity, and Scale in Hydroclimatic Systems
Authors: Sivakumar Bellie
Published: March 2024

Hydroclimatic systems are complex nonlinear dynamically-evolving systems, often made up of a large number of interconnected components that change both in space and in time. Therefore, any effort towards reliable modeling and forecasting of hydroclimatic systems requires proper selection of scientific concepts and methods. Many different scientific concepts and methods have been proposed in the literature and applied to numerous hydroclimatic systems, processes, and problems around the world. Among such, concepts and methods based on chaos theory, complex networks, and fractal theory have been found to offer unique and useful avenues for studying hydroclimatic systems and, thus, have been finding widespread applications in recent times. The purpose of the present study is to discuss the advances in the applications of these concepts to hydroclimatic systems and to look toward the future. This is done through: (1) presenting some key aspects of chaos theory, complex networks, and fractal theory and their relevance to hydroclimatic systems; (2) reviewing various applications of these concepts to hydroclimatic systems, processes, and problems; (3) addressing important data-related issues in the applications of these concepts to hydroclimatic systems; and (4) offering specific directions to advance these concepts and applications further, especially in the context of future grand challenges associated with hydroclimatic systems.
Fresh water on Earth four billion years ago
Authors: Gamaleldien Hamed , Wu Li-Guang , Olierook Hugo K.H. , Kirkland Christopher L. , Kirsche Uwe , Li Zheng-Xiang , Johnson Tim , Makin Sean , Li Qiu-Li , Jiang Qiang , Wilde Simon A. , Li Xian-Hua
Published: March 2024

The operation of a hydrological cycle (i.e., exchange of water between the land, oceans, and atmosphere) has significant implications for the emergence of life. The oldest confirmed single-celled organisms at ~3.48 billion years ago (Ga) (Pilbara Craton, Western Australia) are thought to have formed in the presence of meteoric (fresh) water on emerged (subaerial) land in a hot spring environment. However, when widespread interaction between fresh water and emerged continental crust first began is poorly constrained. In this study, we use >1000 oxygen isotope analyses of Jack Hills detrital zircon to track fluid-rock interactions from the Hadean to the Paleoarchean (~4.4–3.1 Ga). We identify extreme isotopically light O (i.e., δ18O < 4.0 ‰) values older than 3.5 Ga. The data define two periods of magmatism with extreme isotopically-light O as low as 2.0 ‰ and –0.1 ‰ at around 4.0 and 3.4 Ga, respectively. Using Monte Carlo simulations, we demonstrate that such values can only be generated by the interaction of crustal magmatic systems with meteoric water. Our data constrains the earliest emergence of continental crust on Earth, the presence of fresh water, and the start of the hydrological cycle that likely provided the environmental niches required for a life less than 600 million years after Earth’s accretion.
One-dimensional land subsidence modelling constrained by electrical logging and its uncertainty analysis
Authors: Makino Asahi , Aichi Masaatsu
Published: March 2024

. Due to the limited availability of core sample test data, the land subsidence modeling is often highly uncertain. On the other hand, the electrical logging data are frequently accessible and might give some information to constrain the spatial distribution of physical properties in land subsidence modeling. Therefore, this study tried to constrain land subsidence model using electrical logging data. The estimated physical properties, based on the combination of existing empirical relations between the resistivity and physical properties, were used as initial values for the model inversion. A calibration process was then conducted by adjusting the physical parameters to reproduce the observed land subsidence. As a result, the obtained sets of physical properties were within the range of typical values in the existing literatures and satisfactorily reproduced the observed subsidence. Furthermore, numerous possible parameter realizations were generated using the Null Space Monte Carlo method to analyze the uncertainty in both physical properties and future subsidence predictions. The results also suggested the potential to reduce the uncertainty of land subsidence predictions by easily available geophysical logging data.
Abnormal Climate and the Market Economy: the Relationship between Reconstructed Solar Radiation and Rice Price during the Famine of 1830s in Japan
Authors: Ichino Mika , Masuda Kooiti , Mikami Takehiko , Takatsuki Yasuo
Published: March 2024

Historically, climate change has played an important role in shaping human societies. Understanding past climate change is essential for human adaptation to future changes. Solar radiation, a key factor in Earth’s energy balance, hydrological cycle, and agricultural productivity, is crucial for understanding these changes. Our study focuses on reconstructing solar radiation from historical documents, shedding light on the historical impacts of climate variation and how past societies were influenced by and adapted to changing climate conditions.In Japan, many historical documents, including daily weather records from the 17th to 19th centuries, have been key to understanding historical climate variations. Utilizing these descriptions, we developed a method for reconstructing solar radiation. This method enabled us to analyze solar radiation patterns from 1821 to 1850, providing valuable insights into climate variations and their socio-economic impacts during this period.Our analysis, which focused on the 1830s Tempo Famine, revealed a clear relationship between climate variations and economic fluctuations. We found that the decrease in solar radiation during the summers of 1833, 1836, and 1838 corresponded with rising rice prices in Osaka, underscoring the impact on agricultural productivity and market dynamics.These findings suggest that the solar radiation pattern in the summer of 1836 dramatically influenced the severe famine, as evidenced by the unusual rise in rice prices. This study refines the understanding of the historical climate impacts on society and highlights the broader effects of climate variation on agriculture and market economies. This emphasizes the need to integrate climate information into economic analyses and could provide valuable insights for developing contemporary climate change policies and adaptation strategies.
Simulation of Record-Breaking Precipitation Events Using an Advanced Stochastic Weather Generator
Authors: Chen Mengzhu , He Xiaogang , Fatichi Simone
Published: March 2024

Over the past few decades, increased record-breaking precipitation events have occurred in many places worldwide, leading to devastating flood disasters. Conventional design criteria for hydraulic infrastructure and flood mitigation projects are generally dependent on the analysis of historically observed data to inform projections of future conditions through fitting a probability distribution. Beyond the conventional stationarity assumption, it is also assumed that the past observed extreme data can approximate well the entire statistical distribution of future events of extreme precipitation. However, conventional methods solely relying on an extreme value analysis have been shown to fail to capture record-breaking precipitation extremes, potentially underestimating the risk of failure of hydraulic structures and flood prevention measures. This study leverages on the capability of a stochastic weather generator (AWE-GEN) to simulate record-breaking precipitation events at a point-scale by reproducing an ensemble of hourly synthetic precipitation time series that accounts for the intrinsic variability of the rainfall process. Compared with conventional extreme value analysis methodologies, the approach is capable of reproducing internal climate variability well and often reproduces extreme values of precipitation, which have not been recorded in the data yet. This study showcases the relevance of stochastic rainfall generators for estimating precipitation extremes for hydrological design under an uncertain climate. 
Seismic anisotropy of the crust and upper mantle beneath eastern Pamir
Authors: Ju Changhui , Zhao Junmeng , Xu Qiang , Li Guohui
Published: March 2024

The East Pamir seismic experiment (8H) was conducted in the eastern Pamir and the adjacent Tarim Basin from August 2015 to May 2017. Utilizing seismograms from the 8H network and nine permanent seismic stations operated by the China Earthquake Administration, we computed shear wave splitting parameters through cluster analysis of the minimum energy method. A total of 452 high-quality individual SKS-splitting measurements were obtained at 39 seismic stations. Given the predominant availability of events with a back-azimuth (BAZ) around ~110° and the absence of a broad range of BAZ values, we opted for a single-layer anisotropic model to interpret the measurements.The upper mantle seismic anisotropy structure in the Western Himalayan Syntaxis (WHS) exhibits distinctive regional characteristics in various regions. Group A comprises 15 stations situated near the Alai Valley and the Tien Shan with a northeast-oriented Fast Polarization Direction (FPD), aligned with the strike of the orogen and the Absolute Plate Motion (APM) azimuthal direction (~80°) of the Eurasian plate. This group exhibits relatively larger Delay Time (DT) and may be originated from the oriented arrangement of olivine crystals in the mantle lithosphere of the Eurasian continent during the northward subduction of the Indian continent. Group B consists of 21 stations located in the eastern Pamir and adjoining Tarim Basin, demonstrating a curved orientation. While this orientation contradicts the APM direction, it approximately parallels the trend of large-scale surface structures. Combining these observations with previous imaging results, we propose that during the northward advancement of the Indian continent, mantle material flow (escape) in the Pamir-Hindu Kush region formed seismic anisotropy structures similar to those in the Western Himalayan Syntaxis (WHS).
Evaluation of ocean tide models in coastal ocean regions of northern Australia and Papua New Guinea using an updated set of short term tide gauges
Authors: Filmer Mick , Seifi Fardin , Claessens Sten
Published: March 2024

The accuracy of global ocean tide models (OTMs) in shallow waters and along coasts impacts on their numerous applications. For example, the use of OTMs to provide tide corrections (‘de-tiding’) for satellite altimetry observations is required for, e.g., sea level studies and marine gravity field recovery. OTMs are also indispensable in the mitigation of striping errors in GRACE and GRACE-FO time-variable gravity field solutions. It therefore follows that OTM errors in coastal and shelf ocean may then introduce biases into the ‘corrected’ satellite altimetry and gravimetry observations with the potential to impact models using these data. The purpose of our study is to assess the accuracy of two high resolution assimilated OTMs (TPXO9v5, and FES2014b) using an updated set of >100 coastal and shelf tide gauges across the northern Australia and Papua New Guinea region. TPXO9v5 and FES2014b are used here because they have previously compared better than other tidal models in adjacent coastal and shelf areas. This study will also provide insight into the tides in this region which contain a mix of shallow and medium depth waters adjacent to the coast, in addition to land and island barriers that result in a complex tidal regime. This study takes advantage of the large number of short-term tide gauges situated on the coast or offshore islands in Northern Australia and Papua New Guinea. This set of tide gauges have observation periods of >30 days, with a number being more than 90 days long which allows the resolution of the major semidiurnal and diurnal tidal constituents. We use harmonic analysis to estimate tidal constants of major diurnal and semi-diurnal constituents from tide gauges then compare them with corresponding values from TPXO9v5 and FES2014b at the tide gauge location. This comparison identifies improvements and also limitations in these OTMs in this region, and their potential impact on tide corrections provided for satellite altimetry products that may propagate into coastal sea surface, and gravity at the coast. The results also provide additional insight into the local tidal patterns in this region, with particular interest in the Torres Strait and surrounding area.
Multi-parameter anomalies of the lithosphere, atmosphere, and ionosphere approximately three hours prior to the M6.8 Luding earthquake in China
Authors: Mao Zhiqiang , Chen Chieh-Hung
Published: March 2024

Pre-earthquake anomalous phenomena in different geospheres have been widely reported.  Scientists found that the anomalies appear days to months prior to earthquakes from distinct geophysical parameters.  It is urgent and challengeable to investigate impending-earthquake anomalous signals for earthquake prediction.  The MVP-LAI (Monitoring Vibrations and Perturbations in the Lithosphere, Atmosphere, and Ionosphere) system was established at Leshan, Sichuan, China in 2021.  The system monitors the changes of over 20 various geophysical parameters from subsurface to ionosphere.  It aims to gain insights into the mechanisms of the lithosphere-atmosphere-lithosphere coupling (LAIC) during natural hazards.  On 5 September 2022, a M6.8 earthquake occurred at Luding, which is approximately 175 km from the MVP-LAI system.  The results show that the seven parameters from the MVP-LAI system simultaneously exhibited abnormal signal approximately 3 hours before the Luding earthquake. The parameters include ground tilts, air pressure, radon concentration, atmospheric vertical electric field, geomagnetic field, wind field, and total electron content. The enhancement in radon concentration suggests that the chemical channel could be a promising mechanism for the coupling of geospheres. On the other hand, air pressure, the geomagnetic field, and total electron content exhibit similar anomalous spectral characteristics. These anomalies may be attributed to atmospheric resonance before the earthquake. Furthermore, the reduction of the horizontal wind speed, and the increase of upward vertical wind support the resonance channel. The results demonstrate that the LAIC before earthquakes could be dominated by multiple potential mechanisms. The multi-parameter anomalies identified in this study guarantee approximately 3 hours of warning for people to prepare for the seismic event and mitigate hazards.
Towards the Predictability of Compound Dry and Hot Extremes through Complexity Science
Authors: Agarwal Ankit , Guntu Ravikumar
Published: March 2024

Compound Dry and Hot Extremes (CDHE) have an adverse impact on socioeconomic factors during the Indian summer monsoon, and a future exacerbation is anticipated. The occurrence of CDHE is influenced by teleconnections, which play a crucial role in determining its likelihood on a seasonal scale. Despite the importance, there is a lack of studies unravelling the teleconnections of CDHE in India. Previous investigations specifically focused on teleconnections between precipitation, temperature, and climate indices. Hence, there is a need to unravel the teleconnections of CDHE. This study presents a framework combining event coincidence analysis (ECA) with complexity science. ECA evaluates the synchronization between CDHE and climate indices. Subsequently, complexity science is utilized to construct a driver-CDHE network to identify the critical drivers of CDHE. A logistic regression model is employed to evaluate the proposed drivers' effectiveness. The occurrence of CDHE exhibits distinct patterns from July to September when considering intra-seasonal variability. Our findings contribute to the identification of drivers associated with CDHE. The primary driver for Eastern, Western India and Central India is the indices in the Pacific Ocean and Atlantic Ocean, respectively, followed by the indices in the Indian Ocean. These identified drivers outperform the traditional Niño 3.4-based predictions. Overall, our results demonstrate the effectiveness of integrating ECA and complexity science to enhance the prediction of CDHE occurrences.
Deep learning-derived anthropogenic and meteorological drivers of surface ozone change in China
Authors: Wang Min , Chen Xiaokang , He Tai-Long , Jiang Zhe , Liu Jane , Liao Hong , Jones Dylan , Shen Yanan
Published: March 2024

Urban air pollution continues to pose a significant health threat, despite regulations to control emissions. Here we present a comparative analysis of the anthropogenic and meteorological drivers of surface ozone (O3) change in China by integrating deep learning (DL) and chemical transport model (CTM) methods. The DL method suggests volatile organic compound (VOC)-limited regimes in urban areas over northern inland China in contrast to strong nitrogen oxides (NOx)-limited regimes in GEOS-Chem simulations. Sensitivity analysis indicates that the inconsistent O3 responses are partially caused by the inaccurate representation of O3 precursor concentrations at the locations of urban air quality stations in the simulations. The DL method exhibits possible weakened anthropogenic contributions to surface O3 rise in the North China Plain, for example, 1.53 and 0.54 ppb/y in 2015-2019 and 2019-2021, respectively. Similarly, GEOS-Chem simulations suggest an accelerated decrease in surface O3 concentrations driven by the decline in nitrogen dioxide (NO2) concentrations. Furthermore, both DL and GEOS-Chem models suggest the reverse of meteorological contributions to the observed O3 change in the North China Plain in 2019-2021, which is mainly resulted from the reversed changes in meteorological variables in surface air temperature and relative humidity. This work highlights the importance of DL as a supplement to CTM-based analysis. The derived O3 drivers are helpful for making effective regulatory policies to control O3 pollution in China.
Distinguishing sediment transport modes in the eastern continental margin of the Korean Peninsula through end-member analysis of surface sediment grain-size distributions.
Authors: Sim Gyutae , Bahk Jang-Jun , Jang Junho , Kim Hyesung , Jeong Jiwon , Um In-Kwon
Published: March 2024

 This study presents a detailed analysis of grain-size distributions of closely spaced surface sediment samples from the eastern continental margin of the Korean Peninsula off Gangneung and Donghae. This region is characterized by a wave-dominated beach, narrow shelf less than 10 km wide, and slopes with varying gradients ranging from 0.7 to 6.3 degrees. Spatial variations in dominant sediment transport modes were identified using end-member analysis (EMA) of the grain-size distributions. The EMA revealed five distinct end-member distributions (EMD) with mean grain sizes of 221.2 μm (EMD1), 89.2 μm (EMD2), 52.4 μm (EMD3), 22.0 μm (EMD4), and 4.5 μm (EMD5), respectively. EMD1, is significant only at two shallow sample sites near the coast, adjacent to the exposed rocky seafloor, indicating an origin from a relict sand during the post-glacial transgression. EMD2 predominates on the shelf and upper slope (40 to 150 m water depths) along the margin, particularly near a local river mouth, suggesting bedload transport of riverine sand by longshore drifts or episodic storm surges. EMD3, potentially representing coarser suspended load, dominates the upper middle slope (200 to 400 m water depths) where the slope gradient is relatively constant, and the isobaths generally run parallel to the shoreline about 15 km apart. EMD4, potentially representing finer suspended load, prevails in the deeper middle slope (400 to 800 m water depths) characterized by varying morphology: narrower and relatively steeper in the northern part, and wider and gentler in the southern part of the margin. The higher proportions of EMD4 extend far offshore in the wider and gentler southern part more than about 35 km, whereas they are limited to within 30 km from the shoreline at the base of the steeper and narrower slope in the northern part. The morphologically controlled EMD4 distributions suggest that a density current was responsible for the offshore fine-grained sediment transport in this margin, rather than diffusion or advection by ocean currents. Finally, the finest EMD5, predominates in the deepest part of the study area, showing no significant further offshore variations, and is interpreted to represent aeolian dust from the Asian inland.
Unveiling the Subjectivity in Ranking of NEX-GDDP-CMIP6 Climate Models Over Munneru River Basin, India
Authors: Keesara Venkata Reddy , Buri Eswar Sai , Kotapati Narayanaswamy Loukika
Published: March 2024

Regional climate modelling has evolved significantly, offering versatile applications across various scales and resolutions. This study aims to provide a comprehensive framework for selecting top five Climate Models at each grid for climate variables in the Munneru River Basin, comes under Lower Krishna River Basin, India. Employing the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) datasets, which are derived from General Circulation Model (GCM) runs under the Coupled Model Intercomparison Project Phase 6 (CMIP6), is compared with the observed precipitation, maximum, and minimum temperature datasets obtained from the Indian Meteorological Department (IMD). These datasets have a spatial resolution of (0.25° × 0.25°) and available from 1970 to 2014. The methodology adopted in this study uses advanced statistical techniques to evaluate the performance of the CMIP6 models. The study incorporates Multicriterion Decision-Making Techniques (MCDM) and Group Decision-Making (GDM) methodologies within the Reliable-Ensemble Averaging (REA) framework. MIROC-ES2L, GISS-E2-1-G and TaiESM1 are the top ranked models for precipitation data. Whereas, BCC-CSM2-MR, ACCESS-ESM1-5 and GFDL-CM4_gr2 obtained as most suitable RCMs for maximum temperature data. For minimum temperature data, MIROC-ES2L, KIOST-ESM and MIROC6 obtained as top ranked CMIP6 models. The projected climate variables, including precipitation, maximum temperature and minimum temperatures, under three distinct Shared Socioeconomic Pathways (SSP) scenarios: SSP 245, SSP 370 and SSP 585 extending up to the year 2100. The spatio-temporal analysis encompasses key climate parameters, identifying trends, variations, and potential anomalies in the Munneru River Basin. This study contributes to the broader context of regional climate modelling research and enhances our understanding of the Munneru River Basin's climate dynamics. The research findings presented in this study aim to understand the methodological advancements in regional climate modelling, performance assessments of CMIP6 models and the application of CMIP6 models in regional process studies.
Emission characteristics of volatile organic compounds from plastics exposed to sunlight
Authors: Choi Narin , An Joongeon , Kim Donghwi , Loh Andrew , Yim Unhyuk
Published: March 2024

Fossil fuel-based synthetic polymers release substantial amounts of chemicals throughout their life cycle. Given their potential for accumulation and persistence in the environment, plastic-associated chemicals released into the surrounding matrix during weathering have gained attention due to potential hazards to both the environment and human health. Particularly, volatile organic compounds (VOCs), characterized by their high vapor pressure, can be emitted into the atmosphere as degradation products from plastics. Despite their significant impacts, the emission characteristics of these VOCs during the weathering process remain poorly understood. This study aims to fill this knowledge gap by systematically characterizing the VOC emissions from plastics exposed to outdoor conditions. Pellets of five types of plastic (low- and high-density polyethylene, LDPE and HDPE; polypropylene, PP; expanded polystyrene, EPS; polyethylene terephthalate, PET) prevalent in marine environments as debris were subjected to year-long outdoor exposure. Physical and chemical transformations were examined through Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometry (FTIR), respectively, while VOCs were measured using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) under controlled heating conditions of 60℃ in a chamber. Over the course of a year, noticeable alterations in color, fragmentation, and the occurrence of cracks were evident in EPS, PP, and LDPE plastics with considerable chemical modifications. Mass spectra of VOCs from plastics susceptible to weathering exhibited increased peak intensity and the number of peaks over time. The proportion of oxygen-containing compounds increased as a function of exposure time, indicating photooxidation of the plastic backbone. VOC emissions in the control group exhibited a decreasing trend throughout the year, indicating their source from residuals contained in the pellets. In contrast, those of the exposure group showed an increasing trend, particularly in LDPE, PP, and EPS, attributed to the production of degradation products. Calculations of potential annual emissions using annual concentration changes revealed a 2.25-fold increase in VOC emissions in sunlight exposure compared with the control group. These findings emphasize the significance of evaluating VOC emissions originating from plastics in environments with direct sunlight exposure, especially beaches, which frequently serve as hotspots for the accumulation of marine plastic debris.Acknowledgement: This study was supported by the grant “Development of technology for impact assessment of plastic debris on marine ecosystem” from the Korea Institute of Ocean Science and Technology (PEA0204).
An Open-Access Repository of Holocene Marine Limit and Relative Sea Level Data for all of Greenland
Authors: Luetzenburg Gregor , Funder Svend V. , Woodroffe Sarah , Kjeldsen Kristian K.
Published: March 2024

The Last Glacial Maximum (LGM) represents a critical period in Earth's history, and understanding the dynamics of the Greenland Ice Sheet (GrIS) during this time is pivotal for predicting its response to present and future climate change. Accurate reconstructions of the LGM ice sheet margin rely on marine limit and relative sea level data, which provide valuable insights into past ice sheet behavior. However, current databases of Greenland marine limits and relative sea levels are incomplete or not readily accessible, hindering scientific progress and impeding collaboration among researchers.Here, we develop an online, open-access database hosted by the Geological Survey of Denmark and Greenland (GEUS) that consolidates all available information on the deglacial marine limit and relative sea level data from Greenland. The data is recorded in the HOLSEA format and includes realistic reporting of errors. The collected data comprises over 3,000 distinct data points, sourced from more than 120 publications and literature entries. These field observations span over 140 years, reflecting the evolution of measurement techniques and a growing comprehension of marine deposit and relative sea level features. By mining all existing databases, original publications, and unpublished data, this new database will provide researchers with a centralized and up-to-date resource for investigating the LGM ice sheet and subsequent deglaciation history.In the future, the database will undergo regular updates to incorporate new findings and adhere to international standards for reporting marine limit and relative sea level data. This initiative forms the baseline for validating reconstructions of the past behavior of the GrIS contributing to more accurate predictions of its future response to changing climatic conditions.
Characterization and Correlation of Pore Structures and Mechanical Properties in Carbonate Mudrock Formations of Central Saudi Arabia
Authors: Abdlmutalib Ammar , Abdullatif Osman
Published: March 2024

This comprehensive study aimed to analyze pore characteristics and mechanical properties of three carbonate mudrock units (Upper Marrat, Tuwaiq Mountain Limestone, and Hanifa formations) in Central Saudi Arabia. Employing a combination of petrographic thin section analysis, helium porosity measurements, X-ray diffraction, backscattered scanning electron microscopy with energy dispersive scanning, micro-computed tomographic scanning, Total Organic Carbon (TOC) analysis, nuclear magnetic resonance, and N2 adsorption analyses, the research identified various pore types and their abundance. Specific lithofacies were determined: three in Hanifa Formation Hawtah Member (LFH1, LFH2, LFH3), two in Tuwaiq Mountain Limestone mudstone (LFT1, LFT2), and two in Upper Marrat Formation (LFM1, LFM2). These lithofacies exhibited distinct pore types, including intra-skeletal, interparticle, and organic matter-hosted pores, linked to diagenetic processes and burial events.
NMR-relaxation time and pore size distribution curves indicated variable pore abundances across these lithofacies, influencing fluid flow simulations for potential reservoir evaluation. The study also integrated lithofacies analysis with TOC, porosity, and mechanical property measurements to assess rock strength and elasticity. Textural and microstructural analyses suggested different depositional environments: lower shoreface intra-shelf basin for Hanifa and Tuwaiq formations, and peritidal low ramp setting for Upper Marrat Formation.
Correlations between mechanical properties and porosity varied, with tensile strength showing a strong relation to porosity and mineral composition. Hard phase minerals exhibited a stronger correlation with elastic moduli. The study found significant differences in rock strength and stiffness across the formations, influenced by sedimentary layering and anisotropy. These findings are crucial for predicting rock brittleness in these Jurassic intervals and their global equivalents.
Projections of future climate changes from the cloud-permitting greenhouse warming simulations
Authors: Lee Sun-Seon , Moon Ja-Yeon , Timmermann Axel , Streffing Jan , Semmler Tido , Jung Thomas
Published: March 2024

Assessing the future risk of natural disasters, securing sustainable energy and water resources, and developing strategies for adapting to climate change remain challenging due to the large uncertainties in regional-scale climate projections. Recent efforts to address this issue include km-scale coupled climate model simulations that resolve mesoscale processes in the atmosphere and ocean, as well as their interactions with the large-scale environment and small-scale topographic features. Our presentation shows the first results from a series of global 9 km-scale greenhouse warming simulations using the AWI Climate Model Version 3 which is based on the OpenIFS atmosphere model at TCO1279 resolution and 137 vertical levels and the FESOM2 ocean model at 4-15 km resolution. By comparing a set of consecutive 10-year time-slice simulations forced by the CMIP6 SSP585 scenario with a transient simulation at a lower-resolution (31 km in the OpenIFS), we identify key differences in weather and climate-related phenomena, including tropical cyclones, ENSO, and regional climate change features that can be attributed to km-scale dynamics in clouds and atmospheric circulation patterns. The findings from our cloud-permitting climate simulations provide valuable insights into the role of small-scale processes in the sensitivity of the regional and global climate.
Investigating high-resolution methane emission uncertainty reduction in Gippsland using in-situ data: A Bayesian inverse modeling and variational assimilation approach
Authors: Aghdasi Sougol , Rayner Peter , Deutscher Nicholas , Silver Jeremy
Published: March 2024

Quantifying methane emissions in Gippsland, Victoria, Australia is challenging due to the presence of multiple emission sources, resulting in overlapping emissions and considerable uncertainty in estimation. To address this challenge, our study investigates the potential to reduce uncertainties in methane emissions in Gippsland through the combination of in-situ data, models, and prior information using a Bayesian inverse modeling and variational approach. We employ a four-dimensional variational in-situ data assimilation technique built around the Community Multiscale Air Quality (CMAQ) model at 2 km resolution for four months in 2019.Initially, we used the Emission Database for Global Atmospheric Research (EDGAR) as a baseline but identified a number of shortcomings in capturing local emissions. To address this issue, we introduced prior estimates from the "openmethane" prior at https://openmethane.org/. We evaluated the underlying Weather Research and Forecasting Model (WRF) meteorological predictions against nearby weather station data, revealing good performance at most times. We validated the performance of our concentration model by comparing it with observational data at the three sites used in the study.We will discuss the results and present the reductions in emission uncertainties. Next steps in the study will integrate these findings to further rectify biases and improve the accuracy of methane emission estimates in the Gippsland region, especially during the intense fire period of 2019-2020.
A cooperative inversion of airborne transient electromagnetic and magnetic methods based on grid mapping
Authors: Lei Da , Ren Hao
Published: March 2024

Imposing structural constraints between grids of variable sizes is problematic because different geophysical techniques employ different grid divisions. We propose a new collaborative inversion approach and utilize it to invert the proposed 2-D ATEM and 2-D Magnetic Methods with Induced Polarization (IP) effects, which overcomes the problem of imposing cross-gradient constraints at different grid sizes. The grid mapping technique is included into the iterative collaborative inversion process by the inversion strategy. The combined data inversion results show that the technique may successfully leverage data complements to improve the accuracy of the medium boundary description results. The concept is suitable to collaborative inversion of geophysical methods with arbitrary grid divisions and successfully solves the problem of mismatched grid divisions in collaborative inversion.
Rare earth elements and yttrium in Oligocene coals of Makum coalfield, Assam (North-east India)
Authors: Sharma Shivam , Das Debabrata , Tiwari Prakash , Mondal Ramkrishna
Published: March 2024

Rare earth elements and yttrium have attracted considerable attention in recent decade due to their crucial roles in modern technology, particularly in the production of electronics, magnets, and batteries. These elements are of particular importance for developed and developing countries, as they play a significant role in clean energy as well as their growth and development. The concentration, distribution, and modes of occurrence of rare earth elements and yttrium in coal from the Oligocene formation in the Makum coalfield were investigated in this study. The study found that the coal samples from the Makum coalfield have a low ash and high sulfur content. Furthermore, the study revealed that the total concentration of rare earth elements and yttrium in the coal samples ranged from 1.48 to 77.61 ppm, with an average of 27.49 ppm. Based on the analysis of the coal samples. Average concentration of rare earth elements and yttrium in the Makum coalfield, as observed in this study, is lower than the concentration found in world average coals. it was observed that the 60ft coal seam had a higher average LREE/HREE ratio compared to the 20ft and 8ft coal seams. This indicates variations in the distribution patterns of rare earth elements and yttrium within the different coal seams. Coals from this region show a positive europium anomaly and have a weak negative cerium anomaly, indicating a significant marine influence during their formation. The sequential leaching used in this study provided valuable insights into the modes of occurrence of rare earth elements and yttrium in the coal samples from the Makum coalfield. Having a comprehensive understanding of the proportions of rare earth elements and yttrium in different forms, such as organic, silicate-aluminate, acid soluble, ion-exchangeable, and water soluble, is crucial for the development of effective methods and technologies for the extraction of these critical elements from coal.
Immobilization mechanisms of Hexavalent Chromium When Reduced by Fe2+-Bearing Clay Minerals Depending on solution pH
Authors: Moon Changyu , Moon Hee-sun , Nam Kyoungphile
Published: March 2024

 Structural iron (Fe3+)-bearing clay minerals, when they are reduced, can mediate electron transfer through the Fe3+/Fe2+ coupling reaction and transform hexavalent chromium (Cr6+) into less toxic Cr3+, which in turn can be removed from the solution by the clay minerals. Two types of clay minerals with different structural iron (Fe3+) contents, montmorillonite (2.3 wt%) and nontronite (22.3 wt%), were subjected to reaction with 50 mM dithionite at pH 9 for 48 hours, resulting in Fe2+ bearing clay minerals, with measured Fe2+ ratios of 0.68 and 0.49, respectively. Subsequently, the Fe2+ bearing clay minerals were reacted with Cr6+ solution with varying pH ranging from 2.5 to 11 in an anaerobic chamber. Results show that the reduction of Cr6+ was observed at all pH conditions, consistent with the stoichiometric ratios with structural iron (Cr6+:Fe2+/1:3). At pH 7 and below, over 99% of the structural iron (Fe2+) participated in the reduction reaction. At pH 9 and 11, however, the reaction exhibited a shortfall, with approximately 7-27% and 20-32% of unutilized structural iron remaining in montmorillonite and nontronite, respectively. According to the Visual MINTEQ model and DTPA extraction experiments conducted on solids obtained, Cr3+ is immobilized through sorption onto the clay mineral surface at pH 4.5 and below, and through precipitation and deposition on the clay mineral at pH 7 and above. SEM-EDS analysis, the presence of precipitated Cr at pH 7 and above was identified, and XPS analysis confirmed its precipitation in the form of Cr(OH)3. 
Assessing Present-Day and Future Perspectives of Climate Impact on Thermal Stress Risks in Korea from 1km High Resolution Scenarios
Authors: Lee Jae-Hee , Sung Hyun Min , Kim Jin-Uk , Shim Sungbo , Chung Chu-Yong , Byun Young-Hwa
Published: March 2024

Among the various thermal stress indices, apparent temperature (AT) is closely related to public health indicators, and consequently is widely used by weather agencies around the world. Therefore, in this study we estimate the changes in AT and contributing components in Korea as a whole and in five major cities (Seoul, Gwanju, Daegu, Daejeon, and Busan) using national standard climate scenarios based on the coupled model inter-comparison project (CMIP6). In the present day, high AT occurs in major cities due to high temperature (TAS) and relative humidity (RH). Our findings reveal that even when TAS is relatively low, large AT occurs with higher humidity. Notably, in future warmer climate conditions, high AT may first appear in the five major cities and then extend to the surrounding areas. An increase in TAS and RH during the pre-hot season (March to June) may lead to earlier occurrence of thermal risks in future warmer climate conditions and more frequent occurrence of high thermal stress events. Our study can serve as a reference for future information on thermal risk changes in Korea. Considering those who have not adapted to high temperature environments, our findings imply that thermal risks will become more serious and that heat adaptation strategies will be needed during the pre-hot season under future warmer climate conditions.