bluuebunny/crossref_metadata_2025 huggingface dataset:
Land Use Change Characteristics in the Pan-Pearl River Basin in China from 1985 to 202
Authors: Fan Wei , Yang Xiankun
Published: March 2024

The changes in land use/cover are essential aspects of studying the impact of human activities on the Earth's surface and global transformations. In this study, utilizing the ESRI Global Land Cover data (ESRI land cover 2020) and the China Land Cover Data (CLCD), along with historical imagery from Google Earth, a comparative analysis scheme for land use classification results was designed. The CLCD dataset was updated, leading to the creation of a land use dataset for the Pan-Pearl River Basin spanning from 1985 to 2020. This dataset was then employed for the analysis of land use changes in the Pan-Pearl River Basin over the past 35 years.The results indicate:(1) Among the seven land use types, the most significant changes in area occurred in the following order: build -up land, cropland, forest land, grassland, shrubland, waterbody, and barren. Notably, there was a substantial increase in the areas of build-up land and forest land, while cropland, grassland, and shrubland experienced significant decreases. The waterbody’area showed a slight overall increase trend.(2) The major land use types undergoing changes varied among sub-basins, with the intensity of land use change ranked as follows: Pearl River Delta region(1.9%) > Coastal rivers in southern Guangdong and western Guangxi(0.20%) > Dongjiang River Basin(0.13%) > Hanjiang River Basin(0.12%) > Xijiang River Basin(0.10%) > Beijiang River Basin(0.08%) > Hainan Island region(0.02%).(3) Within the sub-basins of the Pan-Pearl River Basin, the most significant increase was observed in the area of built-up land, exhibiting a continuous expansion trend with a total increase of 12184 km2. This increase was primarily due to the conversion of cropland, forest land, and waterbody. The most significant decrease occurred in cropland, with a total reduction of 10435 km2, mainly transitioning to built-up land and forest land. The phenomenon of built-up land encroaching on cropland was particularly prominent, especially in the Pearl River Delta region. Forest land also showed a decreasing trend, mainly attributed to cultivation and the encroachment of built-up land. The reduction in grassland area was more pronounced in the Xijiang River Basin, primarily transforming into forest land, cropland, and built-up land. The study reveals that the rapid development of socio-economics and industry, coupled with an increase in residents' consumption levels, serves as the primary driving force behind land use changes in the Pan-Pearl River Basin. Additionally, land use and management policies play a crucial role as driving factors in the region's land use changes. This research aims to provide a scientific basis for formulating policies related to the region's land resources and land management, holding significant importance for preserving ecological balance and fostering sustainable development in the basin.
Resonant Wave Excitations of Suprathermal Populations in the Solar Wind and Terrestrial Magnetosphere
Authors: Hamd Shaaban Mohammed Shaaban , López Rodrigo A. , Lazar Marian , Poedts Stefaan
Published: March 2024

It is believed that the suprathermal populations of electrons and protons in the solar wind and terrestrial magnetosphere (with energies exceeding those of the bulk population up to several keV) can offer key answers to many major problems, such as the origin of energetic solar particles from interplanetary shocks, particle acceleration by the energy dissipation of the small-scale wave fluctuations, but also a certain level of kinetic turbulence which can explain the non-equilibrium quasi-stable states of space plasmas. Due to their low density and relatively high energy, these populations are collisionless, which means that their dynamics is governed by wave-particle interactions, especially resonant Landau or cyclotron interactions. We present here a series of recent results that demonstrate that the suprathermal populations, whether in the form of a less-drifting halo or the field-aligned beams/strahls, are mainly responsible for the resonant excitation of kinetic wave instabilities. The in-situ observations confirm both the electromagnetic fluctuations triggered by temperature anisotropy and the predominantly electrostatic excitations induced for instance by electron beams.
Quantum Computing for Future Super Large-Scale Plasma Simulations: A Novel Approach for Simulating the Vlasov-Maxwell System
Authors: Higuchi Hayato , Pedersen Juan , Yoshikawa Akimasa
Published: March 2024

The space plasma environment, extending from the Sun to the Earth, includes regions of frozen conditions, zones of anomalous resistance caused by electromagnetic turbulence, interconnected regions characterized by weakly ionized gas systems in strong magnetic fields, coupled neutral-atmosphere chemical processes, and pure neutral-atmosphere collision systems. Owing to their complex interactions, an inclusive understanding and forecasting of the space environment remains an elusive goal, even with the advancements in high-performance instrumentation and in-situ observation of satellites. Therefore, it is imperative to develop space plasma simulations capable of providing comprehensive insights, ranging from local spatial domains to the global schematic.Historically, the development of space plasma simulations has been constrained by computational time, memory capacity, and data storage limitations, resolving complex phenomena with restricted physics at local space scales.Recently, as quantum computing hardware has advanced, quantum algorithms have proven to benefit exponential speedups. There has been a focus on the practical applications of quantum computing in finance, chemistry, fluids, and a variety of fields (e.g., Bouland et al.,[2020], Cao et al.,[2019], Egger et al.,[2020] and Budinski, [2022]). Then a quantum algorithm for the collisionless Boltzmann equation using the discrete velocity method was developed by (Todorova and Steijl, [2020]).We have developed a quantum algorithm for the six-dimensional Boltzmann-Maxwell equations for collisionless plasmas with reference to (Higuchi, et al.,[2023]). We applied this methodology to propose a quantum approach that predicts kinetic and multiscale plasma dynamics.In this presentation, we will introduce a quantum algorithm for performing super large- scale plasma simulations in a quantum computer and estimate the performance required by this task for future quantum error tolerant large-scale quantum computers. We will also discuss the prospects for applications that can be expected in our field, based on trends in the development of quantum computer hardware and software.
Utilizing Various Geospatial Data for Debris Flow Geological Hazard Characterization and Mapping at Jerai Geopark, Malaysia
Authors: Md.Razli Mohamad Rashidi , Md Aripin Mohamad Faruq Syahmi , Mohd Hellmy Muhammad Afiq Ariff , Hamat Muhammad Faris Qusyairi , Mohamad Zakaria , Jaapar Abd Rasid , Ali Azizan , Zakaria Mohamed Syahrizal
Published: March 2024

Gunung Jerai, or Mount Jerai, is in northern Malaysia, a tropical forest where the intrusion of the granitic batholith and metasedimentary rocks controls the topographical condition. Due to the geological aesthetic and the socio-economic history, Gunung Jerai was gazetted as a National Geopark named Jerai Geopark. The geological disaster at Gunung Jerai on 18th August 2021 significantly impacted approximately 1000 families in the region, driven by a maximum cumulative rainfall of around 200mm per 3 hours. This study aims to determine the geological and geomorphological characteristics of the debris flow event on 18th August 2021, which affects mainly three catchments: Seri Perigi Catchment, Batu Hampar Catchment, and Titi Hayun Catchment by using geospatial technique. Three main remote sensing techniques were utilised to achieve the aim of the study, namely IfSAR, LiDAR, and photogrammetry. Aerial photogrammetry was conducted using fixed-wing UAVs with mounted camera sensors covering the catchment areas to visualise the current terrain condition after the debris flow event, which is utilised for the individual landslide inventory, debris flow path, formation of the natural temporary dam, and deposition of the debris flow materials. LiDAR was also employed separately using multi-rotor UAV to conduct detailed terrestrial mapping of selected major landslides to determine landslide classification such as landslide type, dimensions, activity, distribution, and causal factors. At the regional scale, DEM from IfSAR and field geological mapping is utilised for demarcation and delineation of geomorphological features and to generate morphometric data, including slope curvature, slope gradient, slope aspect, flow direction, and flow accumulation, which is derived from the DEM. This information is crucial for disaster management and mitigation efforts, aiding in better preparedness and response. These abstract aims to explain how each geospatial data is utilised and optimised to characterise the debris flow disaster event. 
Neglecting hydrological errors can severely impact predictions of water resource system performance 
Authors: Thyer Mark , McInerney David , Kavetski Dmitri , Westra Seth , Maier Holger , Shanafield Margaret , Croke Barry , Gupta Hoshin , Bennett Bree , Leonard Michael
Published: March 2024

Risk-based decision making for water resource systems often relies on streamflow predictions from hydrological models. These predictions are integral for estimating the frequency of high consequence extreme events, such as floods and droughts. However, streamflow predictions are known to have errors due to various factors such as incomplete hydrological understanding, parameter misspecification, and uncertain data. Despite these errors being well known, they are frequently neglected when undertaking risk-based decision-making. This paper demonstrates that neglecting hydrological errors can impact on drought risk estimation for high stakes decisions with potentially severe consequences for water resource system performance. A generic framework is introduced to evaluate the impact of hydrological errors for a wide range of water resource system properties. This framework is applied in two Australian case study catchments, where we use a stochastic rainfall model, the GR4J hydrological model, a residual error model, and a simplified reservoir storage model to estimate water resource performance metrics (risk and yield). The results underscore the impact of neglecting hydrological errors on decision-making. In one case study catchment, the yield was over-estimated by ~15%-55%, resulting in the (actual) risk of running out of water being ~2-30 times larger than reservoir design. The magnitude of these errors in water resource performance metrics is striking, especially considering that the streamflow predictions appear reasonable based on typical performance metrics (e.g., NSE of ~0.7). The errors in performance metrics stem from the complex propagation of hydrological errors through the water resource system modelling chain. By accounting for critically important hydrological errors we can mitigate highly erroneous risk estimates and improve decision-making related to water resource management
Examination of Magnetic Helicity and Plasma Oscillation Periods in the Active Region NOAA12353 Prior to three C-Class Flares.
Authors: Wisniewska Aneta , Korsos Marianna B. , Kontogiannis Ioannis , Soós Szabolcs , Erdélyi Robertus
Published: March 2024

This work aims to investigate the long-period oscillations of NOAA12353 prior to a series of C-class flares and to correlate the findings with the 3-5 minute oscillations that were previously studied in the same active region. The objective of this work is to elucidate the presence of various oscillations with long periods in the lower solar atmosphere both before and after the flare events. Understanding the relationship between oscillations in solar active regions and their solar eruption activity is essential. To detect long-period oscillations the emergence, shearing, and total magnetic helicity flux components were assessed from the photosphere to the top of the chromosphere. To analyse the magnetic helicity flux in the lower solar atmosphere, linear force-free field extrapolation was used to construct a model of the magnetic field structure of the active region. Subsequently, the location of long-period oscillations in the active region was probed by examining the spectral energy density of the measured intensity signal in the 1700Å, 1600Å, and 304Å channels of the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO). Significant periods of oscillations were determined by means of wavelet analysis. Based on the evolution of the three magnetic helicity flux components, 3-8 hour periods were found both before and after the flare events, spanning from the photosphere to the chromosphere. These 3-8 hour periods were also evident throughout the active region in the photosphere in the 1700Å channel. Observations of AIA 1600Å and 304Å channels, which cover the chromosphere to the transition region, revealed oscillations lasting 3-8 hours near the region where the flare occurred. The spatial distribution of the measured long-period oscillations mirror the previously reported distribution of 3-5 minute oscillations in NOAA12353, seen both before and after the flares. This case study suggest that varying oscillation properties in a solar active region could be indicative of future flaring activity.
Relationship between Tropical Cyclone Size Asymmetry and Anomalous Motion
Authors: Tang Xiaodong , Li Huilin , Fang Juan
Published: March 2024

Challenges persist in accurately predicting sharp changes in tropical cyclone (TC) motion over a short period of time, even with the employment of state-of-art forecasting technologies. The precise connection between these sudden changes and specific TC structure remains unclear. Here, we delve into the relationship between TC asymmetry (TCA) of outer-core size and anomalous motion, using best-track data spanning the period from 2001 to 2022. Results indicate that TCs characterized by lower TCA tend to display more pronounced deflections than their normal motion. Furthermore, fast-moving TCs exhibit heightened asymmetry and a propensity to accelerate, whereas slow-moving ones lean towards greater symmetry. In addition, TCs demonstrating substantial angular deviations are more prevalent at lower speeds, while fast-moving ones rarely generate anomalous deflections. These findings provide valuable insights into the potential impact of TCA on anomalous TC motion, which can ultimately be used to enhance the accuracy of TC track forecasting.
Research on Construction and Application Of Groundwater Resources Carrying Capacity Model in Typical Semiarid Areas
Authors: Gao Fei , Wang Yubao
Published: March 2024

Groundwater is crucial for the economic development in arid and semi-arid areas. However, groundwater resources have been over-exploited for meeting the increasing demands in agriculture, industry and domestic use. Therefore, identifying the key factors influencing groundwater resources carrying capacity (GRCC)GRCC and providing the optimal strategy is critical for sustainable use of groundwater resources. The present study constructed a new GRCC index (D) for assessing the long-term GRCC variation in Zhangjiakou of Hebei Province, China (ZJK) using Budyko equation, Gravity Recovery and Climate Experiment data (GRACE),Global Land Data Assimilation System data (GLDAS), sector water consumption data and GDP data. And we also identify the key factors influencing the GRCC in ZJK using optimal water allocation model and Decision Support System for Agro-technology Transfer model. Our results shows that Budyko-derived long-term (1948–2018) groundwater storage changes (GWC) have declined from −310.9 to −455.6 cm and the large number of constructed wells for irrigation has accelerated the decline of groundwater resources in ZJK. Our results also showed the time series of D in ZJK were < 30%, 30%3, which was reduced by 14% compared to base scenarios in 2016. Also, cropping rotation systems H7 to H9 (H7: two year fallow-maize rotation; H8: two year fallow-potato rotation; H9: two year fallow-wheat rotation)) obtained the lower annual average net water use (14–70 mm) compared to other cropping rotation systems (62–253 mm). The significant difference of net water use, crop yields, water use efficiency and accumulative groundwater table depth changes of nine different cropping systems indicated H4 and H8 is suitable in the study region. Our results are useful for selecting suitable cropping systems based on the water use for local farmers.
Recent increasing trend of global CO2 growth rate due to a slowdown in terrestrial carbon uptake
Authors: Park Chaerin , Jeong Sujong
Published: March 2024

The global atmospheric CO2 growth rate is a product of the combined effects of emissions and uptake from both anthropogenic and natural carbon sources. Therefore, an evaluation of the global CO2 growth rate should be preceded to understand the global carbon-climate process. In this study, we analyzed the long-term changes in the global CO2 growth rate from 1991 to 2020, using data from 42 global sites and model simulations to assess recent changes in the global carbon-climate feedback process. Our results indicate that the annual CO2 growth rate has increased by 0.032 ppm yr-2 since the 2000s. A comprehensive assessment of carbon cycle components contributing to atmospheric CO2 growth rate changes reveals that the strengthening of this rate is linked to a decline in terrestrial carbon absorption over the last decade. This decline is primarily associated with a slowdown in the increasing trend of Net Primary Productivity. Consequently, the reduced terrestrial carbon uptake in recent decades contributed to an approximately 3 ppm increase in global CO2 concentration by 2020. Our findings highlight that the vegetation's carbon uptake capacity can no longer offset anthropogenic CO2 emissions, underscoring the importance of achieving global carbon neutrality in climate change mitigation. This work was supported by Korea Environment Industry & Technology Institute(KEITI) through Project for developing an observation-based GHG emissions geospatial information map, funded by Korea Ministry of Environment(MOE) (RS-2023-00232066)
Estimation of Hydraulic and Thermal Parameters Using Convolutional Neural Network and Hydraulic Tomography
Authors: Liang Che-Wei , Tsai Jui-Pin
Published: March 2024

The ground-source heat pump (GSHP) is an efficient thermal exchange system that utilizes natural environmental heat for heating and cooling. Heat exchange efficiency depends not only on factors such as pipe material and diameter but also on groundwater's flow field and soil's thermal parameters. This study aims to estimate hydraulic and geothermal parameters by utilizing convolutional encoder-decoder architecture neural networks and hydraulic tomography, a data collection strategy. The proposed method is named THT-NN. To examine the capability of the THT-NN on parameter estimation, we developed numerical experiments to test THT-NN. Further, to produce the training and validation data pairs, we create a two-dimensional heterogeneous groundwater and heat transport model by TOUGH2 with constant injection patterns and 10000+ realizations of parameter fields. The groundwater heads and temperature collected from the monitoring well groups are used to develop two channels of the input layers, and four parameters' fields (hydraulic conductivity, porosity, heat conductivity, and specific heat) are used to develop four channels of the output layers. Subsequently, the estimated parameters results are examined by R2 and root mean squared error. The performance of the proposed THT-NN is discussed in this study.
Cold-laboratory experiments to observe meltwater and ice layer interactions in snowpacks
Authors: Shiggins Connor , Mair Douglas , Lea James , Nias Isabel
Published: March 2024

The fate of percolating surface meltwater encountering ‘impermeable’ ice layers is uncertain in the accumulation zone of the Greenland Ice Sheet (GrIS). Often, ice layers are considered to retard meltwater and cause lateral runoff. However, modelled and field-based observations in the percolation zone of the GrIS have suggested ice layers are not necessarily impermeable and meltwater can breakthrough, percolating to deeper depths of snow/firn and consequently inferring a greater refreezing capacity within the accumulation zone. The physical and thermal conditions which control the permeability of ice layers remain unclear and effective parameterisation of these processes is lacking for snow/firn modelling of melt, refreezing and runoff. Here we present repeat cold-laboratory experiments which seek to understand how meltwater interacts with thin ice layers (5 to 20 mm) for two differing thermal regime contexts whereby the surrounding snow/firn thermal regime is either (i) below or (ii) at the melting point.We find that under extreme melt regimes, ice layers continually retard wetted fronts of percolating meltwater when the thermal regime of the snowpack is below the melting point. This barrier results in the snowpack at depth remaining at least ~1oC cooler than snow above the ice layer which is saturated with meltwater. We also find that the ice layer forces ~35% of the percolating meltwater to runoff, cooling the overlying snow and increasing the refreezing capacity of the snow closer to the snowpack surface. The remaining ~65% of meltwater ponds and later refreezes on the ice layer, thickening the impenetrable surface.When the thermal regime of the surrounding snow/firn is at the melting point, we find that meltwater is able to pond without refreezing, resulting in the ice layer failing and allowing deeper percolation into the snowpack. These findings suggest that the thermal regime of a snowpack is crucial for the structural integrity of an ice layer and thus the permeability of a snowpack.Consequently, these findings have implications for parameterising meltwater runoff and ice layer integrity in snow and firn models which incorporate ‘impermeable’ barriers in their domains. Future work will continue to explore similar experiments with thicker ice layers (~60 mm) to determine whether ice layer breakthrough is primarily a function of snow/firn thermal regime and/or ice layer thickness. 
The role of dissolved organic matter chemodiversity in driving bacterial and fungal community patterns at a continental scale
Authors: Wang Jian , Osterholz Helena , Bai Edith , wang Chao
Published: March 2024

Dissolved organic matter (DOM) in natural ecosystems is intimately associated with microbial communities. To unravel the relationship between patterns of DOM and microbial communities at a continental scale, we combined using high-throughput sequencing and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), we characterized DOM chemodiversity and bacteria and fungi community patterns in 55 soil samples collected from a 4000-km sampling through northern to southern in China, which are currently suffering great pressure from climate change. Our research findings demonstrate a clear biogeographic pattern in the diversity of bacteria and fungi, primarily influenced by environmental variables and the distribution patterns of DOM compounds. Soil pH and MAT are key factors that influence the diversity and composition of bacterial and fungal communities. In addition to environmental factors, the diversity of tannin-like compounds plays a crucial role in shaping the biodiversity of bacterial and fungal communities. The composition of protein/amino sugar- and carbohydrate-like compounds, primarily impacts the community composition of bacteria and fungi. This is likely determined by the substrate preferences of microorganisms, while these microbes are evolutionarily conserved.
Investigating the Complexities of LS PIV in River Contaminations: A case study of Varuna River Basin
Authors: Bajpai Mayank , Mishra Devyan , Gaur Shishir , Srivastava Ojas
Published: March 2024

This study delves into the intricate challenges associated with employing Large Scale Particle Image Velocimetry (LS PIV) in river systems affected by anthropogenic contamination and algae, with a specific focus on the Varuna River Basin. The presence of pollutants and the proliferation of algae pose unique obstacles to the accurate assessment of flow dynamics and sediment transport using LS PIV technology.In our investigation, we utilize a setup consisting of Jetson Nano with a camera. The setup is checked for feasibility for two cameras: i) GoPro Hero 7 camera  and ii) a Sony IMX219-200 Camera. The integration of these technologies allows for real-time observations with Real Time Messaging Protocol (RTMP), providing a dynamic perspective on the impact of contaminants and algae on the LS PIV measurements. Through this detailed case study, we scrutinize the complexities arising from the interplay of contaminants and algal growth, examining their effect on the data captured by our setup. Lastly, a holistic comparison of both the setups is done. The findings contribute valuable insights for researchers and practitioners working on water quality assessment and river management strategies in regions facing similar challenges.
Increase in anthropogenic mercury pollution over the past centuries in Northeast China as reconstructed from multi-lake sediment cores
Authors: Neupane Bigyan , Bao Kunshan , Chen Minqi , Thapa Poonam , Meadows Michael E.
Published: March 2024

The rise in human activities in northeast (NE) China has resulted in increased emissions of environmental pollutants. Their measurement is crucial to evaluate the extent and timing of the longer-term anthropogenic environmental changes. This study presents the measurement of mercury (Hg) concentration and accumulation rate in 11 lake sediment cores from Songnen Plain in NE China to reconstruct the historical deposition of Hg as an indicator of the changing scale of anthropogenic activities. The results demonstrate an increasing trend of Hg concentration, concurrent with the increased anthropogenic emission, beginning from the early 1900s, accelerating through the mid-1950s and slightly decreasing from the late 1990s up-core. The anthropogenic Hg increase coincides with New China's foundation, precipitating social and economic reforms and rapid industrial and economic growth. Measurements of the Hg enrichment factor in all the cores point out anthropogenic contribution to Hg accumulation, and the geoaccumulation index shows the lakes are generally moderately polluted by Hg. The historical trend of the Hg accumulation rate matches the region's temporal progression of biomass burning and fossil fuel consumption. The findings elucidate the extent of anthropogenic pollution in the Anthropocene and underline the importance of identifying Hg sources to reduce emissions and implementation of effective mitigation strategies.
Water use efficiency response of plant communities to drought in different growing periods in alpine meadow
Authors: Hu Guozheng
Published: March 2024

The drought is becoming more frequent and severe with changing precipitation pattern in the future. How the water use efficiency responds to drought in different periods during the growing season has become a key scientific issue to explore the response mechanism of carbon and water cycle coupling process to drought in alpine meadow ecosystem. This project focused on the response mechanism of alpine meadow ecosystem productivity to drought and the relationship between productivity, evapotranspiration (or rainfall) and water use efficiency under simulated drought events in the early and middle growth seasons, and discuss the response mechanism of water use efficiency of alpine meadow ecosystem to drought. The result showed that (1) the delayed green-up under early growing season drought and advanced withered date under middle growing season drought occurred in graminoids, weeds and plant community, which indicated ‘escape strategy’ to drought. (2) the effect of advanced withered date was divergent among graminoid and weeds on the aboveground net primary production, which may lead to a stronger resistance of community productivity to middle growing season drought. (3) besides soil water deficit, the limited accumulation of aboveground biomass inhibited the physiological process of carbon exchange in alpine meadow community either. However, the carbon exchange process presented an over compensation mechanism, and the material distribution strategy may vary after rainfall restoration. (4) early growing season drought had no significant effect on water use efficiency of alpine meadow community (p > 0.05), while water use efficiency increased significantly under middle growing season drought (p < 0.05). The main reason is that the plant community is more sensitive to early growing season drought, which depressed the aboveground biomass, while aboveground productivity of alpine meadow plant community has stronger resistance to middle growing season drought. This project studied the response mechanism of alpine meadow ecosystem to extreme drought events in different periods, which has great scientific significance to the study of ecosystem response to extreme climate events, and provides a scientific basis for predicting and simulating the response of alpine meadow ecosystem in Northern Tibet to climate change in the future, especially the change of precipitation pattern.
Highlighting future climate extremes in CMIP6-based convection-permitting simulations over the Black Sea Basin
Authors: Kelebek Mehmet Baris , Batibeniz Fulden , Önol Barış
Published: March 2024

The frequency and severity of extreme weather events, including temperature and precipitation extremes, have been increasing globally due to human-induced climate change. The Black Sea Basin (BSB), with its complex topography and strong air-sea interactions, is particularly susceptible to climate change and serves as a hot-spot for studying regional climate extremes. To obtain reliable information in BSB, high-resolution convection-permitting simulations are necessary. In this research, we performed convection-permitting climate simulations for historical (2005–2014) and future (2061–2070) periods to investigate the changes in temperature and precipitation extremes and underlying mechanisms based on the SSP3-7.0 climate change scenario over the BSB. To achieve this, we downscaled the CMIP6-based MPI-ESM1.2-HR outputs to 3 km horizontal resolution using the WRF model. The future simulation demonstrates an increased exposure to warm extremes as indicated by the positive change of the TX90P index by about 18% and an increase of the heat wave duration index (HWDI) reaching 55 days per year over the BSB. These changes primarily occur over the highlands of Eastern Anatolia due to enhanced land-atmosphere interactions. In March, a change in low-level circulation leads to a sudden warming of approximately 6°C and an early onset of the melting season, resulting in a 20% reduction in snow cover over Eastern Anatolia. This shift increases extreme temperatures due to a substantial snow albedo feedback caused by a 10% reduction in surface albedo in this area. Furthermore, our analyzes highlight the intensification of daily and sub-daily precipitation along the coastal regions of the Black Sea. Particularly in winter and autumn, the ratio of daily extreme precipitation amounts to the seasonal total precipitation (R90PTOT index) reaches 45% in the future over the eastern Black Sea. Additionally, daily precipitation probabilities shift towards higher values for extreme precipitation amounts in the same area with maximum precipitations exceeding 280 mm/day. At the sub-daily scale, this region experiences an intensification in hourly precipitation throughout the day due to a 22% increase in low-level moisture flux resulting from 1°C warmer sea surface temperatures in winter. The increased extreme precipitation in the autumn is associated with the intensification of afternoon precipitation along the Black Sea coasts of Türkiye. This study emphasizes the importance of convection-permitting climate simulations in improving our understanding of climate extremes in the topographically complex BSB. It provides valuable insights for mitigation and adaptation efforts in this climate change hot-spot.Acknowledgment: The numerical calculations reported in this paper were fully performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRUBA resources).
Determination of the solubility, diffusion coefficient and hydrate stability of hydrogen sulfide in water and brine
Authors: Jiang Lei , Wu Chuanjun , Sun Jiyue , Lin Juezhi
Published: March 2024

The dissolution and diffusion process of hydrogen sulfide (H2S) in aqueous solutions are critical in the formation of many metal deposits and the stability of H2S hydrate also play an important role in natural gas exploitation and transportation due to the tendency of H2S to form hydrate at low temperature and high pressure, which can lead to pipeline blockage. In this study, the solubility and diffusion coefficient of H2S in water and brine as well as the stable conditions of H2S hydrates have been determined using fused silica capillary cell, high pressure optical cell, high pressure reactor, and Raman spectrometers.The details are as follows: (1) H2S solubility data in water were obtained at temperatures up to 573 K and pressures up to 100 MPa. These new data extend the predictable range of previous models. (2) The diffusion coefficients of H2S in water at 0.1–2 MPa and 273.1–373.1 K and in four brine solutions (0.62, 1, 2, and 3 mol•kg−1 NaCl) at 1 MPa and 273.1–373.1 K were determined. The results showed that the diffusion coefficient increased with the temperature and was inhibited by salinity. (3) The stability of H2S hydrate in water and brine including NaCl, KCl, MgCl2, NH4Cl, Na2SO4 and K2SO4 at the temperature range from 273.4 to 298.8 K, pressure ranging from 1.13 to 21.90 bar, and salinity from 3.4-20.0 wt.% were investigated. The results showed that the inhibitory effect of six electrolytes on H2S hydrate formation is in the order of MgCl2 > NH4Cl > NaCl > KCl > Na2SO4 = K2SO4.
Vertical ozone transport over the Tibetan Plateau and its impact on downstream areas
Authors: Tian Rongxiang , Jin Zhan , Zhu Yancheng , Xiao Chenyu
Published: March 2024

    Ozone is a crucial component of the atmosphere, serving as both a filter for ultraviolet radiation and a significant constituent of greenhouse gases. Additionally, it plays a vital role in photochemical smog. The complex terrain of the Tibetan Plateau makes it a sensitive and vulnerable region to global environmental and climate changes. Using the fifth reanalysis data for ozone from the European Centre and employing statistical and diagnostic analyses, we investigated the vertical transport of ozone and its downstream impacts. The results show that during summer, the predominant factor contributing to the formation of an "ozone hole" over the plateau is the upward transport of ozone with low concentrations from the troposphere. Conversely, in winter, the transportation of ozone with elevated concentrations from the stratosphere to the troposphere through specific channels significantly influences the distribution of ozone across the plateau. The blocking effect of the plateau causes elevated concentrations of lower tropospheric ozone downstream in the westerlies, at the same latitude. The research holds significant practical value for a comprehensive understanding of the patterns of ozone variation over the plateau and its downstream impacts, contributing to disaster prevention and mitigation efforts.
Temporal evolution of resonance frequencies as a proxy to monitor nonlinear site response: a case study using KiK-net data in Japan
Authors: Lai Ssu-Ting , Schibuola Alessandra , Bonilla Luis Fabian , Cotton Fabrice
Published: March 2024

The comprehension of earthquake ground motion amplification in soft sediments, influenced by the contrasting physical properties of rock and soil, faces challenges due to nonlinear site responses. Nonlinear effects, driven by distinct stress-strain behavior in soils under substantial loads, result in modified propagation velocity of the media, shifts in resonance frequencies, stronger damping, and reduced amplification. Identifying nonlinearity is particularly challenging, especially in the absence of a reference site. In addition, prevalent approaches in ground motion prediction studies often rely on empirical equations utilizing numerical computations that are difficult to validate, instead of incorporating the nonlinear effects present in the data.In this study, we introduce a novel approach by constructing resonance curves derived from seismic waveforms recorded at the surface stations within the KiK-net network in Japan. These curves not only provide the resonance frequencies at a specific site but also serve as proxies for broadband site response, all while excluding site amplification. Our approach unveils the extent of frequency shifts in resonance frequencies, elucidating the interplay between events and sites across varying ground motion levels. Validation through borehole responses from the KiK-net network demonstrates the robustness of our methodology in characterizing the subsurface solely based on surface recordings. This contribution aims to identify both linear and nonlinear resonance frequencies using all available earthquake data at any site, which can help improve ground motion prediction studies, and more accurate seismic hazard assessments.
Mechanisms of the Indian Ocean surface warming pattern in CMIP5 and 6 models
Authors: Suresh Gopika , Kwatra Sadhvi , Vialard Jérôme , Danielli Vincent , Suresh Neetu , Lengaigne Matthieu
Published: March 2024

The latest assessment report of the Intergovernmental Panel on Climate Change highlights an accelerated warming of the Indian Ocean (IO) compared to the global average. Coupled Model Intercomparison Project Phase 5 and 6 (CMIP5/6) projections also indicate a distinct warming pattern, reminiscent of the Indian Ocean Dipole (IOD), characterized by enhanced warming in the Arabian Sea and western Indian Ocean alongside a reduction in the IO branch of the Walker Cell. This study uses an SST heat budget adapted from Zhang and Li (2014, hereafter ZL14) across 46 CMIP5/6 simulations, to examine the drivers of the IO mean warming and its spatial distribution, for both the multi-model mean (MMM) and inter-model diversity.Differing from the prior ZL14 approach, this study incorporates feedback related to downward longwave heat fluxes. While ZL14 highlighted downward longwave fluxes as the main driver of the IO average warming, our results reveal a dominant role of latent heat flux changes for both the MMM and diversity. These changes are further related to a basin-scale wind speed reduction, linked to the winter monsoon & IO Walker cell branch weakening.Regarding the spatial pattern, our results emphasize a key role in the Bjerknes feedback in driving the IOD-like pattern for both the MMM and inter-model diversity. There is indeed a strong relationship across models between the IOD-like warming pattern, rainfall increase over the western IO, weakened equatorial easterlies, an east-west dipole in thermocline anomalies and the contribution of oceanic processes to surface warming. In the Arabian Sea, the enhanced warming is controlled by a seasonally varying balance, with the evaporative cooling feedback dominating during spring and summer when upwellings are strong, and the wind speed reduction associated with the winter monsoon weakening dominating later in the year.Overall, these results call for more comprehensive process-oriented studies with more sophisticated approaches (ocean or coupled model sensitivity experiments) to unravel the IO warming mechanisms.Keywords: Indian Ocean warming, Air-Sea Interaction, IOD-like warming, Walker cell weakening, Arabian sea warming, Coupled model intercomparison project (CMIP)
Exploring the interaction between global changes, soil properties and vegetation patterns on soil phosphorus transformation in alpine grasslands of the Tibetan Plateau
Authors: Cao Zuonan , Gao Qingzhu , Scholten Thomas , Kühn Peter , He Jin-sheng , Guan Zhen-Huan , Ganjurjav Hasbagan , Hu Guozheng , Hu Shanting
Published: March 2024

The grassland ecosystems of the Tibetan Plateau have witnessed substantial transformations in recent decades, driven by various global factors, including alterations in temperature and precipitation, nitrogen (N) deposition, and regional effects. Despite documented shifts in species richness and distribution towards higher elevations, there is a scarcity of comprehensive plant and soil data along elevation gradients in alpine grasslands. The intricate interplay of soil properties and nutrient supply on vegetation patterns at high altitudes, particularly the response of the "grass-line" to global warming, remains unexplored. To bridge these knowledge gaps, our research investigated the impacts of global changes, specifically warming and N deposition, and soil properties on soil phosphorus (P) transformation and plant P uptake. Leveraging insights from long-term nutrient addition experiments, random sampling, and open-top chamber experiments along elevation gradients in an alpine grassland on the northeastern Tibetan Plateau, the study delved into soil properties such as texture, bulk density, soil organic carbon (SOC), and soil P fractions. Furthermore, it explores plant and microbial P pools, P acquisition strategies, and biomass. Results revealed that N input had a discernible effect on plant P requirements, particularly under conditions of deficient soil available P. Changes in P acquisition strategies wielded a more substantial influence on community structure and composition than alterations in root traits. The addition of P significantly impacted plant growth, signifying a shift from nitrogen to P limitation with increased N input. Soil properties exhibited variations among sites, while pH remained stable in the 0–10 cm soil depth due to the adequate levels of calcium and magnesium in the soil, which could buffer the impact of N deposition on soil acidification in the grassland ecosystem. Strong positive correlations observed between organic P pools, SOC, and total N underscored the pivotal role of soil organic matter in sustaining soil P reserves. More importantly, P limitation did not emerge as the primary factor propelling grasses to higher elevations; instead, other soil properties and nutrients might play a key role. These findings underscore the importance of specific combinations of soil properties in constraining plant growth on the northeastern plateau, thereby influencing biodiversity and biomass production. This research highlights the factors influencing effective soil nutrients and provides valuable insights for predicting the impact of global changes on the stability and productivity of alpine grassland ecosystems.
High-speed electron flows in the terrestrial magnetotail
Authors: Liu Huijie , Li Wenya , Tang Binbin , Wang Chi
Published: March 2024

High-speed electron flows play a crucial role in the energy dissipation and conversion processes within the terrestrial magnetosphere, particularly in regions associated with magnetic reconnection, such as the vicinity of electron diffusion regions (EDRs) and separatrix layers. NASA's Magnetospheric Multiscale (MMS) mission was specifically designed to reveal electron-scale kinetic processes occurring in Earth's magnetosphere. In this study, we conduct a comprehensive survey of high-speed electron flows in the terrestrial magnetotail, utilizing MMS observations spanning from 2017 to 2021. Our analysis identifies a total of 642 events characterized by electron bulk speeds exceeding 5,000 km/s. Notably, these events exhibit a clear dawn-dusk asymmetry, with 73% of them occurring in the dusk magnetotail. Along the magnetotail's normal direction, we find that 37.7%, 21.8%, and 40.5% of the events are located in the plasma sheet, plasma sheet boundary layer, and lobe region, respectively. The occurrence rate of these events peaks when the magnetic field strength is approximately 19 nT. High-speed electrons predominantly move along magnetic field lines in the plasma sheet boundary layer and lobe region, while in the plasma sheet, they traverse along arbitrary directions with respect to the magnetic field. Our study contributes to a deeper understanding of the complex electron dynamics under various plasma and magnetic field conditions within Earth's magnetotail.
Seasonal Dynamics of the Compositions and Concentrations of Microbiomes in the Atmospheric Environment at a Subtropical Location
Authors: Lee Patrick K.H. , Miao Yanhao
Published: March 2024

Understanding the types of microbes present and their concentrations over time is essential for deciphering the physical, chemical, and biological processes in the atmospheric environment. In this study, Hong Kong, which experiences four distinct seasons, was selected as the study site. High-throughput amplicon sequencing of the 16S rRNA gene was utilized to analyze the microbiomes present, while a light/laser-induced fluorescence (LIF) instrument was employed to characterize the real-time concentrations of fluorescent aerosol particles (FAPs) or bioaerosols. Seasonal variations in the microbiomes were observed, primarily driven by less abundant taxa that were unique to specific locations. Conversely, spatial variations were minimal, suggesting a homogeneity of microbiomes within the scale of a city. The major taxa of the microbiomes reflected the local environments (e.g., aquatic and soil), with neutral assembly processes dominating each season, indicating a minor role of selection in microbial assembly in the air. FAP concentrations were highest in the fall and winter seasons, deviating from measurements in temperate and tropical regions. Bioaerosol concentrations exhibited diurnal patterns, with higher concentrations during the daytime and lower concentrations at nighttime. Certain atmospheric pollutants were associated with bioaerosol concentrations, and positive matrix factorization analysis identified anthropogenic sources as key drivers of bioaerosol concentrations. In summary, the application of molecular techniques and LIF-based instrumentation has provided insights into the microbial composition of the atmospheric environment in a subtropical location, facilitating further investigations into the interactions involving these biological components.
Onset of the Carnian Pluvial Episode: a record by clay minerals from the Misurina stratigraphic succession (Dolomites, Italy)
Authors: Alverà Greta , Dal Corso Jacopo , Cruciani Giuseppe , Caggiati Marcello , Gianolla Piero
Published: March 2024

The Carnian Pluvial Episode (CPE) was a climate and biological crisis that occurred in the early Late Triassic (~232–234 Ma) and has been linked to large igneous province volcanism, which would have injected large quantities of volcanic CO2 into the Carnian atmosphere and triggered global warming and a strong enhancement of the hydrological cycle. In the marine sedimentary succession of the Dolomites, the CPE is marked by a crisis of the early Carnian microbial-dominated high-relief carbonate platforms and an increase of siliciclastic deposition. To understand weathering processes related to the more humid climate that occurred at the onset of the CPE, we present organic-carbon isotope data and clay mineralogical composition of 112 fine-grained samples taken from a basinal stratigraphic series outcropping near Misurina (Auronzo di Cadore, Dolomites, Italy). The succession encompasses the topmost San Cassiano (early Carnian) and the base of the Heiligkreuz (late early Carnian) formations, corresponding to the interval recording the onset of the CPE. Overall quantitative mineralogical composition was obtained from whole-rock samples XRD analysis using Rietveld method. Analyses on oriented mounts of the