bluuebunny/crossref_metadata_2025 huggingface dataset:
Lightning Activities near the Red Sea: Effects of Aerosols Morphology and Local Meteorology
Authors: Farahat Ashraf , Dayeh Maher
Published: March 2024

Lightning activity is one of the global natural hazards that pose significant risks to human life and numerous aspects of society's technological infrastructure. Understanding the linkage between aerosols present in the atmosphere and lightning activity is important to further advance our knowledge of the global lightning activity cycle.Saudi Arabia and Yemen host one of the world’s largest desert areas namely the Empty Quarter (al-Rubea Al-Khali). Moreover, Saudi Arabia is one of the world’s largest oil exporters with many water desalination, petrochemical, and cement industrial plants, while large cities in both Saudi Arabia and Yemen have large construction projects and vehicle emissions. This increases both natural and anthropogenic aerosol loading in both countries.  Meanwhile, the inland regions close to the Red Sea are one of the 500 hottest lightning regions in the world. This work identifies a possible correlation between lightning activity and aerosol loading.Using data of individual lightning strokes from the Global Lightning Detection Network (GLD360), in conjunction with remote sensing measurements of the aerosol optical depth (AOD) obtained at 500 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard the Terra and Aqua satellites during active lightning days, we examine the evolution of lightning activity in two geographically and topologically different regions over Saudi Arabia and Yemen. One region extends inland to the desert (R1) and the other is in the southwest mountainous region that is close to the Red Sea (R2). In both regions, results from thunder days only indicate that lightning is strongly and positively correlated with the AOD loading, up to AOD ~ 0.8, after which the trend flattens or reverses direction. Results suggest the two opposite effects that aerosols could indirectly have on lightning activity are at play. The mountainous region exhibits a much stronger linear relation compared to the inland region. Furthermore, both regions exhibit seasonal and asynchronous lightning activity and AOD loading. The year 2018 in R1 shows very high lightning activity, likely linked to the 2018 intense dust storms in the region.
Iron hydride FeHx in the Earth's inner core and its geophysical implications
Authors: Zhang Feiwu , Yang Hua , Muir Joshua
Published: March 2024

The Earth's inner core, formed as a result of cooling and crystallization of the outer core iron alloys, plays a fundamental role in the evolution of our planet. There is still much uncertainty on the phases of iron at high pressures and temperatures. Furthermore, the chemical composition of the Earth's core has attracted growing attention in the last several decades. The presence of small amounts of light alloying elements such as Si, O, S, C, and H in the core has been proposed to explain the seismic and density anomalies in the Earth's core. Among these light elements, hydrogen has the highest abundance in the solar system, and therefore, it is potentially one of the main light elements in the Earth's core.
In order to explore the possibility, structure, mobility, and concentration of H in the Earth's inner core, especially under high temperatures, we have employed evolutionary crystal structure prediction methods and density functional theory (DFT) calculations to examine the structural models of Fe-H binary at core pressure and temperature conditions[1]. The influence of temperature on the stabilities of the Fe-H binary has been simulated within the quasi-harmonic approximation (QHA) framework. Molecular dynamics calculations are also performed to detect the state and mobility of H under core conditions. The ionic conductivity of Fe-H alloy, as well as the H concentration in the Earth's inner core, was determined, and its implications on the composition and evolution of the Earth's core are discussed [2,3].
Our study suggests that the Fe-H binary adopts numerous possible structures under core-like conditions, while the fcc structure is concluded to be a strong candidate for the H-bearing phase in the Earth's inner core. The high mobility of H in the solid Fe lattice at high temperatures indicates that H is transferred to a superionic state, where the H superionic state transfer temperature in Fe fcc lattice is ∼500 K higher than that in the hcp Fe system. H is a key light element for reducing the density and elastic modulus of Fe, but the wave velocities of the Fe-H binary still remain too high to account for the seismological observations of the inner core. Other light elements are, therefore, also required to match all the geophysical models.
References:
[1] Yang H et al (2022) Geochemistry, Geophysics, Geosystems, 23 (12), e2022GC010620
[2] Yang H et al (2023) American Mineralogist, 108 (4), 667-674
[3] ] Yang H et al (2023) Geophysical Research Letters, 50 (22), 2023GL104493
Downscaling and reconstruction of high-resolution precipitation fields using a deep residual neural network: An assessment over Indian subcontinent
Authors: Murukesh Midhun , Kumar Pankaj
Published: March 2024

Deep learning methods have emerged as a potential alternative for the complex problem of climate data downscaling. Precipitation downscaling is challenging due to its stochasticity, skewness, and sparse extreme values. Also, the extreme values are essential to preserve during downscaling and extrapolating future climate projections, as they serve as trivial signals for impact assessments. This research looks into the usefulness of a deep learning method designed for gridded precipitation downscaling, focusing on how well it can generalize and transfer what it learns. This study configures and evaluates a deep learning-based super-resolution neural network called the Super-Resolution Deep Residual Network (SRDRN). Several synthetic experiments are designed to assess its performance over four geographically and climatologically distinct domain boxes over the Indian subcontinent. Domain boxes over Central India (CI), Southern Peninsula (SP), Northwest (NW), and Northeast (NE), exhibiting diverse geographical and climatological characteristics, are chosen to assess the generalization and transferability of SRDRN. Following the training on a set of samples from CI, SP and NW, the performance of the models is evaluated in comparison to the Bias Correction and Spatial Disaggregation (BCSD), a renowned statistical downscaling method. NE is a transfer domain where the trained SRDRN models are directly applied without additional training or fine-tuning. Several objective evaluation metrics, like the Kling-Gupta Efficiency (KGE) score, root mean squared error, mean absolute relative error, and percentage bias, are chosen for the evaluation of SRDRN. The systematic assessment of SRDRN models (KGE~0.9) across these distinct regions reveals a substantial superiority of SRDRN over the BCSD method (KGE~0.7) in downscaling and reconstructing precipitation rates during the test period, along with preserving extreme values with high precision. In conclusion, SRDRN proves to be a promising alternative for the statistical downscaling of gridded precipitation.Keywords: Precipitation, Statistical downscaling, Deep learning, Transfer learning, SRDRN
The Bredehoeft Problem: Verifying Accuracy of Linearized Salvage Evaluation in Water Table Aquifers due to Groundwater Pumping
Authors: Zlotnik Vitaly , Rabinovich Avinoam , Cardiff Michael
Published: March 2024

In water table aquifers, evapotranspiration can be reduced due to the groundwater pumping. These changes must be evaluated to assess how much water can be used for groundwater withdrawals. Although this salvage phenomenon was well understood a long time ago since pioneering studies of Theis and Bredehoeft, the models always applied numerical techniques to treat their non-linearity, most commonly using MODFLOW. However, in cases of limitations on watershed data properties, analytical methods were used successfully for practical evaluation of water balance components (e.g., stream depletion rates). Previously we made a breakthrough in solving the Bredehoeft problem analytically by linearization. This solution permits evaluating stream depletion and loss of storage in addition to salvage. Using compiled ranges of input parameters, the detailed analysis of solution using the COMSOL software indicates that linear approximation of the problem has good accuracy in practical ranges. Diagrams for evaluation of accuracy for broad ranges of parameters defining stream-aquifer connection and evapotranspiration are presented. Results can be used for analyses of the watershed water balances.
Quantitative partitioning of temporal origin of transpiration into pre- and post-plantation under deep-rooted vegetation on the Loess Plateau of China
Authors: Li Min , Chen Guangjie
Published: March 2024

Deep-rooted vegetation transpires a considerable amount of deep soil water with different ages in the unsaturated zone. However, the tradeoffs between new water of transpiration (temporally originating from post-planting precipitation) and old water of transpiration (temporally originating from pre-planting precipitation) across the vegetation lifespan are poorly understood. In this study, we collected soil samples from beyond 28 m soil depth on the Loess Plateau of China to investigate the influence of deep-rooted vegetation on the age of soil water and analyze the proportion of new and old water of transpiration in the unsaturated zone under grassland, 22-year-old apple orchard, and 17-year-old peach orchard. Water isotopes (2H, 18O, and 3H), solutes (chloride, nitrate, sulfate), and soil water content were used to identify the critical water ages in the unsaturated zone (one-year water age, water age corresponding to stand age, and the maximum water age of transpiration), and to determine soil water deficit, soil evaporation loss fraction, and potential groundwater recharge. The results showed that soil water mainly moved as piston flow in these soil profiles, and deep soil water largely came from heavy precipitation. Deep-rooted vegetation restrained new pore water velocity and potential groundwater recharge. New pore water velocity declined from 0.40 m yr-1 to 0.14 m yr-1 and 0.34 m yr-1 for apple and peach, respectively. Deep-rooted vegetation decreased groundwater recharge by 9.46 % for apple and 7.04 % for peach, compared to grassland. Over the vegetation lifespan, annual average transpiration was 500.56 mm yr-1 and 468.89 mm yr-1 with maximum water age of 63 years and 45 years for apple and peach, respectively. The transpiration of deep-rooted vegetation mainly used new water (94.97 % for apple and 97.47 % for peach). The total old water of transpiration was 553 mm for apple and 209 mm for peach. Our results identify the temporal sources of vegetation water use, offering new insights into the transpiration process of deep-rooted vegetation.
The metric α(CH3O2) indicates ozone formation sensitivity towards NOx and VOCs in the global troposphere
Authors: Nussbaumer Clara M. , Pozzer Andrea , Lelieveld Jos , Fischer Horst
Published: March 2024

While stratospheric ozone (O3) is essential to life on Earth, tropospheric ozone can have adverse effects. At the surface, it contributes to air pollution and impacts human health. Further, it is the third most important anthropogenic greenhouse gas enhancing global warming and climate change, and its radiative forcing efficiency is largest in the upper troposphere. Therefore, it is imperative to investigate ozone formation and its sensitivity to the precursor gases nitrogen oxides (NOx) and volatile organic compounds (VOCs). Commonly used metrics apply to the planetary boundary layer but fail to identify O3 formation sensitivity at higher altitudes. We introduce the new metric α(CH3O2) to indicate O3 sensitivity, which represents the share of methyl peroxy radicals (CH3O2) forming O3 through the reaction with NO in competition with the reaction with HO2 terminating the catalytic (O3 forming) HOx cycle. We demonstrate the versatility and applicability of α(CH3O2) by investigating a number of studies, including several based on data from stationary field measurements, aircraft observations and model simulations in various locations around the globe, across all altitudes from the surface to the upper troposphere and over a time period of the past 20 years. We identify where O3 chemistry is sensitive to NOx or VOCs in the global troposphere considering a wide range of ambient conditions.
Rheological behavior of Crushed Rock Flows
Authors: hu wei , McSaveney Mauri
Published: March 2024

The enduring mystery surrounding the unexpectedly high mobility of expansive geophysical flows has persistently tantalized researchers since Albert Heim's investigation following the catastrophic landslide at Elm, Switzerland. Despite numerous claims of resolution, the mechanism underpinning this remarkable mobility has remained elusive. To delve into the flow dynamics of crushable dense granular material exhibiting high mobility, a series of high-speed rotary shear experiments was conducted using various mineral particles. Our findings revealed a more explicable flow behavior when interpreting shear resistance as viscous rather than purely frictional. Notably, we observed a dramatic decrease in viscosity for crushable materials, stabilizing at a consistently low level, crucial in dictating the remarkable fluidity observed in large-scale geophysical flows like rock avalanches. The flow exhibited two distinct phases, demarcated by a critical point of weakening within accumulated strain for crushable material. The initial phase reflected a simple Newtonian or non-Newtonian-like flow, while the subsequent phase was more intricate, displaying a profound viscosity drop stabilizing at a constant level under substantial strain. This discovery holds significant implications for understanding hypermobile geophysical phenomena, including rock avalanche dynamics, natural faulting, and crater collapse. In particular, we demonstrate that the behavior of rock avalanches is similar to that of complicated fluids with extensive weakening and that the viscosity of this special “liquid” is as low as 500 Pa·s. This finding can also help improve the accuracy and reliability of the numerical simulation of rock avalanches by using the viscous model obtained from the experiments.
Impacts of compound hot-dry events on vegetation productivity in the Tibetan Plateau under climate change
Authors: Xi Xiazhen , Yuan Xing
Published: March 2024

Tibetan Plateau is one of the sentinels of climate warming, with complex vegetation types and noticeable regional differences. Tibetan Plateau also has the largest area of permafrost and seasonal frozen soil. With global warming and increasing compound hot-dry events, the ecohydrological processes have been changed substantially. On one hand, high temperatures can promote vegetation gross primary productivity (GPP) and respiration (Re), and also affect them by altering the permafrost freeze-thaw state. On the other hand, drought events can cause water stress and affect vegetation growth. However, the net primary productivity (NPP) of alpine ecosystem in response to compound hot-dry events is unclear. This study incorporates the carbon-nitrogen processes into a high-resolution land-hydrology coupled model, i.e., Conjunctive Surface-Subsurface Process model version 2 (CSSPv2), and conducts long-term simulations to investigate the ecohydrological effect of the changes in compound hot-dry events. Specifically, we find that GPP on the Tibetan Plateau is more sensitive to changes in soil moisture than vapor pressure deficit during flash droughts. However, the sensitivity of GPP to high vapor pressure deficit in the southeastern Tibetan Plateau increased during the hot periods of flash droughts, which have higher temperatures and more intensive radiation. Whether the soil water stress or atmospheric water stress dominates the changes in NPP is also being investigated, by using both high-resolution land-eco-hydrology model simulation and satellite remote sensing.
River incision on hotspot volcanoes: insights from paleotopographic reconstructions and numerical modelling
Authors: Gourbet Loraine , Gallen Sean F. , Famin Vincent , Michon Laurent , Ramanitra Miangaly Olivia , Gayer Eric
Published: March 2024

The influence of climate on landscape evolution in natural settings remains debated. Here, we focus on tropical hotspot volcanic islands because they exhibit relatively uniform lithology and experience significant precipitation and climate gradients. Furthermore, intermittent volcanic flows effectively “reset” the landscape that begins to evolve post-eruption. Thus, we can constrain initial conditions by reconstructing the initial geometry of radiometrically dated volcanic flows. We constrain landscape evolution through time in several volcanic islands with strong climate gradients to assess the role of climate on incision. We perform topographic reconstructions to calculate long-term basin-averaged erosion rates in two islands of the Réunion hotspot (Réunion, Mauritius) and compile published erosion rates on Réunion and Kaua’i (Hawaii hotspot). We define the time since incision started as the age of the surface incised lava flow. To calibrate incision parameters on all three islands, we use the stream power model and apply a data-driven Bayesian approach to obtain the erodibility, K, the drainage area exponent, m, and the slope exponent, n. We also calculate a normalized erodibility index, Kn, using n = 1 to directly compare results among the different study sites. Erosion rates of Réunion Island range from 9.9 ± 0.5 mm/yr to 5.2 x 10-3 ± 2 x 10-4 mm/yr and erosion rates in Mauritius Island range from 6.5 x 10-2 ± 8 x 10-3 mm/yr to 5.1 x 10-3 ± 4 x 10-4 mm/yr. Incision efficiency seems to decrease with time since incision started from 63 ka to ~300 ka and then does not vary significantly with time since incision started from ~300 ka to 4300 ka. This is likely due to the covariation between the age of volcanism repaving and precipitation rates on Réunion, which is related to the configuration of the island’s two volcanoes – the active Piton de la Fournaise located on the windward side and the dormant Piton des Neiges on the center and leeward side. Our empirical calibration of the stream power law shows high dispersion in n and Kn on each individual island. m ranges from 0.2 to 2.9, and Kn ranges from 2.3 x 10-7 to 9.8 x 10-4 m1-2m/yr. For Réunion, we identify a positive trend between mean annual precipitation and erosion rates, and between mean annual precipitation and Kn, for low to moderate erosion rates (
Evaluation of historical SO2 emissions based on an inversion of ice core records using atmospheric transport modeling
Authors: Plach Andreas , Eckhardt Sabine , Pisso Ignacio , Chellman Nathan , McConnell Joseph R. , Stohl Andreas
Published: March 2024

Sulfur dioxide (SO2) is an air pollutant which can have harmful effects on both human health and the environment. Furthermore, SO2 also contributes to climate change — SO2 emissions form sulfate aerosols that act as cloud condensation nuclei, increasing cloud formation and decreasing solar radiation reaching the surface. An accurate knowledge of past SO2 emissions is therefore essential to quantify and model the associated global climate forcing. Current bottom-up SO2 emission inventories used for historical Earth System Modeling (ESM) are poorly constrained by observations prior to the late 20th century.Here we revisit and evaluate the historical SO2 emission inventories of the last 150 years used in the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our emission reconstruction is based on an inversion technique employing an array of ice core records of deposited sulfur and atmospheric transport/deposition modeling. The inversion technique minimizes discrepancies between the spatial-temporal patterns of emission inventories and the observed deposition at the ice core sites.We find substantial differences between reconstructed SO2 emissions and existing bottom-up inventories which do not fully capture the spatial-temporal emission patterns. Our results imply that changes to existing historical emission inventories might be necessary in order to ensure an accurate modeling of the Earth’s climate sensitivity within future ESM simulations.
Designing the TUDS rainfall observatory in northern Ghana
Authors: van de Giesen Nick , Annor Frank , Ayambila Sylvester , Dogbey Richard , Hoogelander Vincent , Kranjac-Berisavljevic Gordana , Kwabena Kingsley , Mackenzie Rob , Schleiss Marc , Uijlenhoet Remko
Published: March 2024

Convective rainfall in West Africa is poorly monitored and understood. There are large gaps between remote sensing rainfall products and what is observed on the ground. There are several reasons for these gaps. First, satellites and rain gauges measure at very different scales so one would expect that remote sensing products contain more events at lower intensities than small gauges. Second, a lot happens between the clouds observed by satellites and the ground. Rainfall may evaporate and move with the wind, causing further disconnects between space and ground observations. There are also indications that clouds in West Africa contain many small drops due to the presence of many aerosols, thereby possibly “misleading” satellite products. Finally, it is likely that there are further factors that are not yet accounted for.In order to tackle this disconnect between ground and space observations, we plan to build the TUD - UDS, or TUDS, rainfall observatory near Tamale and Nyankpala in northern Ghana. The following are initial ideas that we would like to discuss at the EGU. It will be a multi-scale observatory, starting at a grid of nine gauges on a 500m grid (1km x 1km total). This small grid should capture the inherent spatial variability of convective rainfall events with convective cells of 2km or less. The largest grid would also contain nine gauges and have an extent of 10km x 10km, or larger. This outer grid would capture the movement of convective cells, including those contained within so-called line squalls. An intermediate grid may complete this picture. The structure will look, more or less, like the one in the picture below.Different instruments will be at our disposal, from simple totalling rain gauges to disdrometers. There will be five Thies disdrometers, one Ott Parsivel, and several TAHMO stations and/or tipping bucket rain gauges. Also experimental intervalometers will be placed in the grid to better understand rainfall structure over time and space. Several instruments will be co-located to examine strengths and weaknesses of the different methods.We explicitly invite comments and contributions.   
TEMBO Africa: The work leading to these results has received funding from the European Horizon Europe Programme (2021-2027) under grant agreement n° 101086209. The opinions expressed in the document are of the authors only and no way reflect the European Commission’s opinions. The European Union is not liable for any use that may be made of the information.
Patterns of disturbance dynamics within the Cerrado-Amazon Transition using time series data and Residual Neural Networks
Authors: Li Chuanze , Harris Angela , da Conceição Bispo Polyanna , Dennis Matthew
Published: March 2024

The Cerrado-Amazon Transition (CAT) is the world’s largest tropical ecotone and separates the Cerrado Savannah from the Amazon Rainforest. Deforestation and degradation of large swathes of the dense Amazon rainforest and Brazilian Savanna is leading to irreversible transformation and a critical loss of biodiversity. An increase in wildfire and agriculture-led deforestation makes the CAT a dynamic ecological border within the internationally known ‘Arc of Deforestation’. Yet, our understanding of the impacts of deforestation and degradation in the CAT is hampered by a lack of knowledge as to where and when these disturbances occur. Here we combine time-series segmentation and deep learning algorithms to identify and quantify disturbances in the CAT over a 35 - year period. Using a combination of the Landtrendr algorithm, Landsat time series data and a Residual Neural Network (ResNet), we identified four different forest disturbance types (forest clearance, savannah clearance, forest wildfire, savannah wildfire) occurring within the CAT, based on their temporal spectral trajectories. Using our approach, we identified  more than 384,000 km2 of disturbance between 1985 and 2020, with forest clearance accounting for the most significant proportion (35%) of the identified change. The accuracy of disturbance detection ranged from 88to 93%, while the accuracy of disturbance type classification reached ~ 95%, although disturbance events occurring within savannas are more difficult to identify, often due to lower initial vegetation cover. The greatest period of disturbance occurred between 1995-1998, due to increased agricultural activity.
Enhancing Carbon Cycle Understanding through Deep Learning: Development and Validation of the Global Carbon Fluxes Dataset (GCFD)
Authors: Shangguan Wei , Xiong Zili , Huang Feini
Published: March 2024

This research tackles the constraints inherent in current global carbon flux datasets and introduces a groundbreaking new dataset, the Global Carbon Fluxes Dataset (GCFD), which integrates cutting-edge deep learning methodologies alongside in situ measurements. GCFD delivers unprecedented high-resolution spatial and temporal data on Gross Primary Productivity (GPP), Terrestrial Ecosystem Respiration (RECO), and Net Ecosystem Exchange (NEE). The Convolutional Neural Network (CNN) model employed in this study surpasses conventional machine learning techniques, demonstrating robust performance in modeling GPP, RECO, and NEE.The precision and spatial granularity of GCFD outshine those of alternative global carbon flux datasets, like FLUXCOM, and it exhibits strong coherence with remote sensing vegetation condition data. Serving as a reliable reference for both meteorological and ecological investigations, GCFD is particularly valuable when high-resolution carbon flux mapping is essential. Its reliability has been rigorously tested by comparative analysis against existing data products, revealing insightful details about the global spatial and temporal patterns of carbon fluxes, especially within tropical and dry climate zones where notable trends have emerged.This study significantly advances our comprehension of worldwide carbon flux dynamics and underscores the untapped potential of deep learning technologies to enhance the quality of carbon flux datasets. Accessible at https://dx.doi.org/DOI:10.11888/Terre.tpdc.300009, GCFD offers data resolutions ranging from 1 km to 9 km.
Projected Increase in Probability of East Asian Heavy Rainy Summer in the 21st Century by CMIP5 Models
Authors: Fu Yuanhai
Published: March 2024

In the summer of 1998, heavy rainfall persisted throughout the summer and resulted in a severe prolonged flooding event over East Asia. Will a similar rainy summer happen again? To date, many studies have investigated projected changes in the seasonality or daily extreme precipitation events over East Asia; however, few studies have focused on the changes in extreme summer-averaged East Asian rainfall. This type of summer is referred to as a “heavy rainy summer (HRS)” in this study, and an investigation of future changes in its probability is performed by analyzing CMIP5 model outputs in historical climate simulation (HIST) and under RCP4.5 and RCP8.5.All models project increased probabilities of HRS by a factor of two to three. The projected East Asian summer rainfall (EASR) (EASRRCPs−EASRHIST) in both climatology and HRS is expected to intensify significantly. The increased EASR could be attributed to significantly intensified water vapor transport (WVT) originating from the tropical Indian Ocean (TIO) and the eastern subtropical North Pacific (SNP), which is a result of the thermodynamic component. The WVT from the TIO would supply more moisture for EASR because of its stronger intensity and faster rate of increase. Meanwhile, the EASR anomaly in HRS relative to climatology (EASRHRS−EASRCLM) would increase by approximately 11%–33%. In HIST, the associated WVT anomaly, caused only by the dynamic component, converges moisture from adjacent land and ocean. However, under the RCPs, the WVT anomaly from the TIO, resulted from the thermodynamic component, would appear and increase by a factor of three to be comparable to the WVT anomaly from the eastern SNP. The latter would result from the dynamic component but increase by only half.
Distribution of aerosol optical depth and possible factors influencing dust optical depth over arid and semi−arid Eurasia
Authors: Zhang Shuang , Detlef Müller
Published: March 2024

In this paper, long-term temporal and spatial distribution characteristics of aerosols in arid and semi-arid regions of Eurasia (30° N - 60° N, 25° E - 90° E) from 2001 to 2021 were studied by combining Moderate−resolution Imaging Spectroradiometer (MODIS), Cloud−Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) (2007-2021) and Ozone Monitoring Instrument (OMI) observations.  Aerosol types over Eurasia were studied based on aerosol optical depth (AOD), Ångström exponent (AE), and aerosol single scattering albedo (SSA). The results show that the average AOD (obtained from MODIS) is high in the Taklimakan, Tar, Kizikom, and Syria deserts. Seasonal aerosol concentrations in Xinjiang, Iraq, Iran, Kazakhstan, Uzbekistan, and Turkmenistan were the highest in spring, the second-highest in summer, and the lowest in autumn and winter. Clean marine and mixed aerosols are the primary aerosol types in the Eurasia. The relative contribution of meteorological factors to dust optical depth (DOD) and its long-term variation have been quantified by stepwise regression model. The model results show that the contribution of humidity at 500 hPa (H500) to the change of DOD is 28%, the contribution of wind speed (WS) to the change of DOD is 19%, and the contribution of temperature (T) to the change of DOD is 12%.  The spatial distribution of the correlation coefficient between DOD and meteorological factors is higher under the bare surface compared to complex terrain. This result highlights the sensibility of meteorological factors on the distribution of DOD in the desert. The results presented in is paper are helpful for understanding the interaction between DOD and meteorological factors.© 2014 xxxxxxxx. Hosting by Elsevier B.V. All rights reserved.
Long-term Carbon Flux Dynamics in Central Taiwan's Cloud Forests: Influence of Biological Disturbances
Authors: Lai Yen-Jen , Yu Jui-Chu , Maneke-Fiegenbaum Falk , Otto Klemm , Lin Po-Hsiung , Yang Cheng-Ying , Nakai Taro
Published: March 2024

In the context of mounting concerns surrounding human-induced climate change and its repercussions, the study delves into the critical role of forests, particularly their ability to absorb and store carbon dioxide. Our focus is on the Xitou Flux Site, situated in the cloud forest of central Taiwan, where micro-meteorological and carbon sequestration observations have been conducted since 2010, employing the eddy covariance method.Noteworthy is the resolution of nighttime drainage issues in 2018, achieved through the implementation of the Lloyd and Taylor model, ensuring the accuracy of the recorded data. A comprehensive analysis spanning the years 2010 to 2022 paints a concerning picture: a substantial decline in the carbon sequestration capacity of the forest, particularly pronounced since 2017.This study investigates the multifaceted factors contributing to this decline, with a special emphasis on the intricate interplay between carbon sequestration and changes in land cover. A significant revelation is the widespread damage inflicted upon the planted Cryptomeria japonica (Sugi) by squirrels through debarking and girdling. This phenomenon emerges as a major driver behind the observed reduction in the forest's carbon sink efficiency.Regrettably, the current state of carbon sequestration in this plantation has reached a precarious equilibrium, characterized by a carbon-neutral status. This underscores the pressing need for immediate and targeted conservation efforts to preserve the ecological balance and enhance the resilience of this vital carbon sink.
Detrital zircon age signatures of the basal Cambrian sandstone unit in North China: implications for drainage divides during global Sauk transgression and separation from Gondwanaland
Authors: Wei Ronghao , Duan Liang
Published: March 2024

The basal Cambrian sandstone unit in the North China craton (NCC) is an example of globally widespread siliciclastic succession that resides on the Great Unconformity and deposited on a hypothesized low-lying peneplain during the Cambrian global eustatic sea-level rise. Detrital zircon age signatures from this distinct sequence enable recognition of the ancient drainage system of the NCC in deep time and track its potential linkage with the Gondwana landmass. LA-ICP-MS U–Pb dating of the fossil-calibrated basal Cambrian (Series 2) detrital zircon samples from seven measured sections reveal marked spatial changes in their age signatures that can be divided into three distinct types. The first is generally characterized by the bimodal age populations with broad peaks at ~1.85 Ga and ~2.5 Ga that correlate with the Archean to Paleoproterozoic basement inboard of the NCC. The second is featured by multi-modal distribution with diagnostic Neoproterozoic peaks that correspond to subregional magmatic record. The third also shows multiple-zircon age populations, but yields significant crystallization ages close to the early Cambrian age. Comparing our new data with existing age spectra for the Cambrian strata across the NCC and the northern Gondwana demonstrates that separate drainage systems did exist in the peneplained basement during global Cambrian transgression and the basal Cambrian unit in the NCC was not a part of the far-travelled sand sheet across the northern margin of Gondwana. The most suitable source for Cambrian-aged grains constrained by paleogeographic restoration is the arc terrane developed along the northern margin of the NCC as a result of subduction of the Paleo-Asian oceanic plate. Our new continental-scale detrital zircon provenance signatures in the basal Cambrian unit suggest that the NCC should be considered a discrete continental block separated by the Proto-Tethys Ocean in the Cambrian, rather than an integral part of the northern Gondwana.
Plutonic Nature of a Transcrustal Magmatic System: Evidence from Ultrahigh Resolution Sr-Disequilibria in Plagioclase Microantecrysts from the Southern Taupo Volcanic Zone, New Zealand
Authors: Zellmer Georg , Coulthard Jr Daniel , Brahm Raimundo , Lormand Charline , Sakamoto Naoya , Iizuka Yoshiyuki , Yurimoto Hisayoshi
Published: March 2024

The residence timescales of antecrystic minerals contribute a key piece of information regarding the petrologic evolution of transcrustal magmatic systems and may be inferred using a combination of observations derived from microanalytical chemistry and diffusion modelling. Here, we present state-of-the-art stacked CMOS-type active pixel sensor (SCAPS) isotopographic images of tephra-hosted plagioclase microantecrysts from Tongariro Volcanic Centre in the southern Taupo Volcanic Zone, New Zealand. These crystals exhibit high-frequency Sr and anorthite zonation at sub-micron spatial resolution. We also find that all crystals display high-frequency intracrystalline Sr chemical potential variations, indicating that they have not resided at magmatic temperature for diffusive relaxation to advance significantly. To quantify crystal residence times at the well-constrained magmatic temperatures of these tephras, we first forward-modeled intracrystalline Sr diffusion over time using numerical methods. Results were then analyzed using novel spatial Fourier-transform techniques developed to understand the systematics the diffusive decay of Sr disequilibria in the spatial frequency domain. This ultimately permitted the estimation of Sr concentration profiles at crystal formation, prior to uptake into the carrier melt at the onset of eruption. Our data imply residence times of days to weeks for the studied microantecrysts. This is inconsistent with long antecryst residence times in magmatic mushes at elevated temperatures, pointing instead to a cool plutonic nature of the magmatic plumbing system beneath the southern Taupo Volcanic Zone.
Refining the Characteristics of Hydrogeolgical Settings in Pingtung Plain of Taiwan
Authors: Liang Chia-Hung , Ke Chien-Chung , Lin Jung-Jun , Lai Tzi-Hua , Huang Chi-Chao , Shao Ping-Hua , Lee Yuan-Hsi
Published: March 2024

To improve the benefits of the groundwater resources management and utilization efficiency of Pingtung Plain located at Southern Taiwan, this study focused on the understanding of the hydrogeological settings and groundwater flow behavior of this area as well as assessing the reasonable of the delineation of  groundwater recharge geologically sensitive areas (GWRA) by various field investigation techniques.Following the aforementioned purposes, totally four boreholes with the depth of 100 meters were drilled spreading around GWRA in 2019. According to the core logging analysis of Zaixing site located at the region of GWRA, we found that the gravel formation, distributed at shallow layer, was playing an important role of the benefit of groundwater recharge due to its hydraulic conductance. Furthermore, the Changxing, Silin and Huamin sites were located spreading around the boundary of the GWRA. The lithology of Huamin site was mainly composed of thick layers of gravel and mud, while Changxing and Silin sites were composed of thick layers of gravel and coarse sand, and thin layers (around 4 to 10 meters thickness) interspersed locally with three to four layers of gravel and coarse sand. The interlayer of fine grain sediments in this area showed that it is unfavorable for vertical infiltration of surface water and rainfall into deeper aquifers. To analyze the characteristics of aquifer and estimate hydrogeological parameters, the constant-rate pumping tests were conducted in two different sites located in GWRA. The hydraulic conductivity (K) and specific yield (Sy) of Zaixing site were 3.8×10-3 m/sec and 0.16 respectively, while those of Silin were 1.6×10-3 m/sec and 0.17. Finally, we could summarize that the Pingtung Plain had the relative higher conductance and capacity of water resources based on the comparison results of the range of hydraulic conductivity and specific yield with nine major groundwater area.Therefore, an elaborate plan of hydrogeological investigation and assessment of groundwater resources of Pingtung Plain are very crucial to face the challenge of water scarcity in the near future.
YeMiGO: Data Processing and Analysis of Underground Superconducting Gravity Data in South Korea
Authors: Oh John J. , Dehghan Mohammad Javad , Woo Ik , Kim Hwansun , Son Edwin J. , You SeungMi , Kim Jeong Woo
Published: March 2024

We present the status of the Yemi micro-gravity observatory (YeMiGO), including the installation, operation, and initial analysis of the gravity data. In October 2022, we installed GWR Instruments Inc,’s iGrav (serial #001) superconducting gravimeter (SG) at Yemi underground laboratory (YemiLab) in South Korea. YemiLab is located approximately 1,008 and 118 meters below the Earth's surface and mean sea level, respectively. The noise characteristics were assessed using one month of raw data collected in September 2023 and compared to those of other seismometer stations. The results show the noise level at the SG station, especially in the seismic band, is significantly low and proves the stability of the Lab.  The research findings also indicate that blasting during mining operations at a distance between ~700 and ~900 meters (please confirm this) from the SG impacted the dewar and barometer pressures as well as the tilt balance data. However, no discernible effects were observed in the raw SG data, leading to the hypothesis that the SG tilt system was able to compensate for the resulting vibrations. After 6 months of continuous data recording from 16th November 2022 to 18th May 2023, a calibration factor of -92.17 μGal∙V-1 was estimated using tidal analysis. In November 2023, a new calibration factor of -94.15 μGal∙V-1 was estimated using parallel measurements with FG5-231 provided by the Ministry of Interior, R.O.C. (Taiwan). Having accounted for various environmental effects, including Earth tide, atmospheric pressure, groundwater level, and polar motion, during the initial six months of data, the residual gravity was obtained. Spectral analysis revealed several unidentified residual gravity power spectrum density frequencies, necessitating further investigation. Co-seismic gravity changes resulting from four earthquakes in May 2023 with different magnitudes and within various distances from the SG station were examined. The M6.2 earthquake that occurred 765 km away was linked to the most notable co-seismic gravity alteration, which recorded a value of 0.561 μGal. The mentioned changes decreased gradually and faded away entirely within half an hour after the SG's first arrival.
Marginal sea-ice is not a major source of iron to support spring blooms in the South Atlantic
Authors: Roychoudhury Alakendra , Buchanan Kayla , Samanta Saumik
Published: March 2024

In the South Atlantic HNLC regions, productivity limitation is largely attributed to light in combination with the unavailability of micro-nutrients, mainly dissolved iron (dFe). Many of these regions fall within the dynamic marginal ice zone (MIZ), which are highly vulnerable to future change in climate where in the past decades Southern Ocean is absorbing more heat than the polar north. It is hypothesized that sea-ice formed in winter concentrates macro- and micro-nutrients and serves as their source, on melting, to surface waters in spring to support phytoplankton blooms, where dFe concentrations can be less than 0.1 nM. For the logistical difficulties in accessing these remote areas, especially in winters, and analytical challenges, sea ice as a source or sink of micro-nutrients in these remote regions has remained understudied and only ~78 dFe usable data is available for the entire Southern Ocean sea-ice.Sea-ice cores were collected in winter and spring from South Atlantic MIZ and analyzed for dissolved and particulate iron (pFe) along with other ancillary data. Ice-core depth profiles of dFe show a typical C-shape with higher dFe concentrations at the top and bottom of the core. dFe profiles did not follow the salinity profiles, suggesting external input of Fe at the top and bottom of the core and not brine drainage. The average concentration of dFe (0.53 ± 0.64 nmol kg-1; n = 34) in sea-ice remained consistently lower than pFe (3.82 ± 2.42 nmol kg-1; n = 11) and there was considerable heterogeneity even in replicate cores collected from the same floe. The measured concentrations translate into a total iron flux (TFe) of 38.05 ± 27.49 mol y-1 (n = 45) in South Atlantic MIZ. Both measured species show regularly lower concentrations than what has been measured from other regions of the Southern Ocean, resulting in the calculated flux from the studied MIZ being 30 times lower than what has been calculated from melting of near shelf ice. Experiments conducted in the laboratory show that majority of the dissolved iron accumulated in sea-ice is released within the first 10% of melting but with complete melting and mixing, resulting net dFe concentrations fall within the Fe-limiting conditions. pFe, although available at higher concentrations in sea-ice, had lower Fe/Al ratio compared to the typical crustal ratio. That is, a more refractory phase is released on melting of sea-ice, which is not ideal for uptake by phytoplankton. 
Release and Transport Characteristics of Heavy Metal Pollutants in Tailings Pond
Authors: Jin Jiaxu , Wu Pengfei , Cui Hongzhi , Zhang Xinlei
Published: March 2024

The lead-zinc tailings pond contains a significant concentration of heavy metal pollutants, such as lead, zinc, copper, chromium, cadmium, mercury, and arsenic. These pollutants exist in the form of ions within the tailings. External environmental factors can facilitate the release and transportation of these heavy metal elements from the tailings, resulting in pollution. The factors influencing pollutant release and variations in heavy metal tailings transport across different media were investigated by employing statistical analysis, leaching tests, and heavy metal soil column experiments based on the results of a case study on the Qingshan lead-zinc mining area. The multi-component solute release transport model for tailings to examine the interplay between concentration and seepage fields was constructed by considering hydrodynamics, mass transfer, and chemical reactions. The COMSOL software was performed to develop a customized model for the transport of heavy metal pollutants, wherein specific boundary conditions were set to enable quantitative analysis and interpretation of the release and migration of heavy metal solutes in tailings. The present study establishes a foundation for comprehending the migration patterns, pollution pathways, and mechanisms of heavy metal pollutants in tailings ponds. Furthermore, it provides indispensable technical support for addressing heavy metal contamination in lead-zinc mining regions and developing impermeable systems for tailings ponds.