bluuebunny/crossref_metadata_2025 huggingface dataset:
Petrogenesis of high-alumina basalts in South China Sea: Implications for magmatic processes associated with the opening of an oceanic basin
Authors: Tian Liyan , Wang Wei , Castillo Paterno R. , Wu Tao
Published: March 2024

International Ocean Discovery Program (IODP) Expeditions on the northern continental margin of the South China Sea (SCS) have nullified the early notion that the SCS is a magma-poor margin. However, there are continuing debates on how the rapid transition from continent to ocean is supported by geochemical and petrologic data, and whether such a process was related to plate subduction or mantle plume activities. Here we present the bulk-rock and plagioclase phenocryst geochemistry of basalts generated during the early spreading (initial and steady ocean) stage of SCS basin extension, which were drilled at IODP Sites U1500 and U1503, respectively. Combined with published data from the late spreading stage of the basin, the new measurements provide an excellent opportunity to examine the magmatic processes associated with the evolution of the SCS basin. Our results reveal that SCS basalts generally exhibit higher Al contents than global mid-ocean ridge basalts, particularly at lower MgO contents, similar to the characteristics of modern arc basalts. Nevertheless, their origins are site-specific and complex. Some U1503 basalts display strong subduction signals in terms of trace elements, and their correlations with Al2O3 content suggest that they are products of partial melting of the mantle wedge, closely related to the northward subduction of proto-SCS. This subduction had a significant effect on triggering the opening of the SCS, rather than by a mantle plume. Basalts from the other sites, including Site U1500, exhibit significant accumulation of plagioclase. Moreover, the An values of the plagioclase in Site U1500 basalts increase with the increase of host magma Al contents, indicating that the floatation mechanism cannot account for plagioclase accumulation. Therefore, we propose that the high abundance of plagioclase in Site U1500 basalts requires rapid ascent of magma, supporting a rapid rifting and strong magmatism during the initial opening of the SCS.
Increased snow depth and vascular plant species promote Arctic soil methane emissions
Authors: Kim Jung In , Yun Jeongeun , Jung Ji Young , Nam Sung Jin , Lee Jaehyun , Kang Hojeong
Published: March 2024

Atmospheric temperatures are steadily rising on a global scale, with the Arctic region experiencing an alarming rate of increase, double that of the global average. This temperature surge not only signifies anticipated changes but also forecasts a consequential rise in winter precipitation. Within the context of climate change, this leads to a significant upturn in net methane (CH4) emissions. During winter, augmented snow depth enhances thermal insulation of the underlying soil, subsequently increasing soil moisture upon melting. This results in warmer and wetter soil conditions, fostering an anoxic environment that stimulates methanogenic activity. Furthermore, methane emissions are accelerated through plant-mediated CH4 transport. Studies propose a potential shift in vegetation communities, favoring vascular species with extensive aerenchyma under warming conditions.While projections suggest an increase in CH4 flux with greater winter precipitation, the combined effects of heightened snow cover and the presence of vascular plant species on CH4 production remain largely unexplored. This study, conducted using snow fences installed since 2017 in Council, Alaska, aims to unravel the legacy effect of deepened snow during winter and plant-mediated transport on soil CH4 emissions during the growing season (Jul–Aug, 2023). Our investigation involves the analysis of soil CH4 flux, soil chemical properties, and microbial abundance and communities in both control and high snow depth (HS) conditions, comparing bare soil and Eriophorum angustifolium dominant soil.Results indicate that deeper snow significantly increased the average CH4 emission rate from 2.65 to 16.6 mg m-2 day-1. The presence of E. angustifolium amplified CH4 emission strength in both control and HS conditions (63.4 and 116 mg m-2 day-1, respectively). Increased CH4 emissions in HS conditions were primarily driven by enhanced carbon source availability and higher ammonium concentrations. Deeper thaw depth in HS conditions increased carbon source availability, particularly in vegetated soils, promoting methanogenic activity. Higher ammonium concentrations in HS conditions contributed to inhibiting methanotrophs from oxidizing CH4.Consistent variations in soil characteristics were observed at a microbial scale, confirming increased methanogenic activity and decreased methanotrophic activity in HS conditions, for both bare and vegetated soil. These findings underscore the synergistic legacy effect of increased CH4 flux resulting from the complex interaction between deepened snow depth and the presence of vascular species, creating conditions conducive to elevated CH4 production during the growing season.
Preliminary Results from Phase One of the WA Array Passive Seismic Project, Western Australia
Authors: Ebrahimi Reza , Murdie Ruth , Yuan Huaiyu , O'Donnell John Paul
Published: March 2024

The first phase of the WA-Array project, initiated by the Government of Western Australia in late 2022. This project marks a ground-breaking seismic imaging initiative with the deployment of 165 seismometers strategically across the state at 40-km intervals. Over a 10-years period, this project will span the entire state, covering over 2.5 million square kilometres, evolving into one of the world’s largest passive-source seismic programs. With a primary focus on mapping the crustal and lithospheric mantle structure, the project also significantly contributes to mineral exploration, energy studies, seismic risk assessments and green energy land use planning.
As a temporary seismic network, the project encountered distinctive challenges in site selection and deployment of diverse instrumentation, requiring strategic compromises between time, budget, feasibility, and project requirements in terms of network geometry and data quality. This paper explores the challenges encountered during Phase One (2022-2023) of the WA-Array project, particularly emphasizing station deployment and data quality control and management. Rigorous validation processes were employed to ensure the reliability and consistency of seismic recordings across the entire array. Due to logistical issues, the deployment consisted of a wide range of instruments which required that the data was comparable across all stations. In order to present a coherent data set which can be used for many studies, all instrument pairs used in the network underwent comprehensive testing on metadata and earthquake waveforms recording quality check through collocation on a slab. In line with industry standards, we also conducted noise level analysis across diverse frequency ranges, estimating Power Spectral Density (PSD) at each station. Comparisons with standard New Low and High Noise Models (NLNM and NLHM) not only validated data robustness but also facilitated the detection of operational issues and monitoring temporal variations in noise levels. This paper presents preliminary data quality results, including insights gained from a comprehensive calibration test, the current status of initial modelling, updates to the model, and adaptive strategies employed to address these challenges.
Trends in Asian summer monsoon anticyclone dynamical diagnostics in reanalyses
Authors: Manney Gloria , Santee Michelle , Millan Luis , Wargan Krzysztof , Lawrence Zachary
Published: March 2024

The area of the Asian summer monsoon anticyclone (ASMA), as defined by contours of Montgomery stream function (MSF) on isentropic surfaces, has been increasing over at least the last four decades. Here we analyze the relationship of the trend in ASMA area to trends in dynamical diagnostics in the ASM region, both inside and outside the ASMA, after 1979 in the MERRA-2, JRA-55, and ERA5 reanalyses.  Trends in geopotential height (GPH) and temperature (from which MSF is calculated) indicate that MSF increases are dominated by increasing temperature (GPH) at levels that are primarily in the troposphere (stratosphere). Trends in MSF, GPH, and temperature are much less clear within the ASMA circulation than those for the entire ASM region, suggesting that other mechanisms, besides the direct effects of increasing tropospheric temperatures, are at play. To further explore these results, we present trends in lapse rate and dynamical tropopause altitudes, easterly and westerly windspeeds bounding the ASMA, and potential vorticity. Overall, weak or inconsistent trends inside the ASMA in most diagnostics likely arise from a complex interplay of mechanisms in this region (which spans tropospheric/stratospheric and tropical/midlatitude conditions), and suggest that the previously reported area trends do not necessarily indicate an increase in “intensity" of the ASMA. In regions both with and without robust trends in dynamical diagnostics, trend results are typically consistent between the three reanalyses studied even when there are biases in the magnitudes of those diagnostics. This generally good agreement indicates that these reanalyses are suitable for more detailed studies needed to fully understand the mechanisms for trends in the ASMA. 
The Variability of Lunar Mare Basalt Properties Inferred from Present-Day Surface Rock Abundance
Authors: Elder Catherine , Ghent Rebecca , Haber James , Hayne Paul , Morgan Gareth , Robinson Mark , Siegler Matt , Williams Jean-Pierre
Published: March 2024

The surface rock abundance map derived from the Lunar Reconnaissance Orbiter (LRO) Diviner Lunar Radiometer Experiment (Diviner) revealed variability in the rock abundance across the surface of the lunar maria [1]. Rocks on the lunar surface break down quickly relative to lunar geologic history [2, 3], so surface rock abundance is likely to be strongly tied to subsurface rock content which could include both coherent layers of mare basalts or large boulders mixed in with regolith. Most of the Moon’s surface is now covered in fine grained regolith, and historically various authors have argued that each surface unit started as a flat coherent layer of rock which gradually broke down into a layer of regolith whose thickness is a function of its bombardment history [e.g. 4, 5]. However, recently Head and Wilson (2020) [6] argued that modern understanding of lunar volcanism suggests substantial variability in post eruption surface conditions (e.g. void space, pyroclastic deposits, etc.) which could affect subsequent regolith development possibly leading to surfaces of the same age having regolith layers of different thicknesses and/or suspended rock populations. We compare the Diviner rock abundance [1] in different maria units defined and dated by Hiesinger et al. (2011) [7] to investigate both the change in surface rock abundance with time, and possible regional variability in rock properties [8]. We find that surface rock abundance does decrease with unit age as expected for a thickening layer of regolith. However, there is significant scatter in this relationship. We calculate the best-fit linear relationship between the median rock abundance and age of the units defined by Hiesinger et al. (2011) [7]. Investigation of the residuals of this fit reveals that they are not random. For example, Mare Australe is similar in age to Mare Tranquillitatis, but nearly all units in Mare Tranquillitatis are rockier than those in Mare Australe. Mare Humorum is notable for being one of the rockiest regions in the maria despite its relatively ancient surface (>3 Ga). These observations support the hypothesis of Head and Wilson (2020) [6], and suggest that further investigation into the properties of present-day surface rocks may provide insight into the initial mare basalts before billions of years of communition. Specifically, future in situ missions across diverse mare locations could offer insights into the variability of basaltic eruption styles that may have formed the lunar maria. [1] Bandfield+ (2011), JGR, 116, E00H02.[2] Basilevsky+ (2013), PSS, 89, 118.[3] Ghent+ (2014) Geology, 42, 1059.[4] McKay+ (1991) Lunar Sourcebook, Cambridge Press, 285.[5] Hörz (1977), PCE, 10, 3.[6] Head+ (2020) GRL, 47.[7] Hiesinger+ (2011), GSA Special Papers, 477.[8] Elder+ (2023) PSJ, 4:244.
Application of the Ntrace tool to investigate long-term P fertilizer effects on gross N transformations in a pasture soil
Authors: Clough Tim , Jansen-Willems Anne , Kleineidam Kristina , Dannenberg Lea , Müller Christoph
Published: March 2024

The Ntrace tool uses soil 15N analysis of soil N pool dynamics to establish soil gross nitrogen (N) transformations. An understanding of what initiates and controls soil N transformation dynamics is critical when considering the environmental impacts (e.g. nitrate leaching and nitrous oxide emissions) and fate of N in pasture soils. Phosphorus (P) is an essential nutrient required by soil microbes that facilitate both soil N and soil organic matter transformations. A laboratory mesocosm study was performed to examine the effect of long-term superphosphate use on soil gross N and soil organic matter transformations. Sheep grazed pasture soils, undisturbed for 71 years, receiving either nil fertilizer (control) or 188 kg ha-1 year-1 of single superphosphate (17 kg P ha-1 yr-1) were collected at a depth of 0 – 7.5 cm. Soils were sieved (4 mm) and placed in kilner jars, whereupon they received treatments that consisted of: 15NH414NO3 + natural abundance 13C perennial ryegrass (Lolium perenne) root material; 14NH415NO3 + natural abundance 13C perennial ryegrass root material; or 14NH414NO3 + 13C enriched ground perennial ryegrass root material. Over 7 days measurements included soil inorganic-N concentration and 15N enrichments, nitrous oxide emissions, microbial biomass, and soil organic C concentrations. Data and initial conclusions from this experiment will be presented with respect to the long-term P fertilizer effects on soil gross N and soil organic matter transformations.
Monitoring spatial and temporal variation of field water quality and sediment organic matter for comparison of satellite image data
Authors: Lee Jun-Ho , Jung Hoi Soo , Ryu Huigyeong , Woo Han Jun
Published: March 2024

Sechura Bay (05°12’ to 05°50’S and 80°50’ to 81°12’W) is delimited in the north by Punta Gobernador and Punta Aguja to the south, has an approximate extension of 89 km2, and is within the Piura Region, Peru. It is considered within the transition zone between cold water transported from the south by the Humboldt Current and warm water of the tropical equatorial region. Sechura Bay is an area of high economic importance and an ecosystem with high marine biodiversity due to fan shell (Argopecten purpuratus) production and artisanal fishing. fan shell is an edible marine species of saltwater shellfish, a bivalve mollusk in the family Pectinidae. To use satellite image data in real-time at the survey point, information such as GIS (geographic information system)-based water depth and classification of the characteristics of rock, gravel, sand, silt, and clay content on the surface is required. It usually consists of factors related to the growth of shellfish (sea temperature, salinity, hydrodynamics, chlorophyll-a, etc.) and factors related to the environment surrounding the shellfish (bottom dissolved oxygen, total organic carbon, sediment acid volatile sulfide, benthic diversity, etc.). For example, the suitability score was ranked on a scale from 1.0 points (least suitable) to 8.0 points (most suitable). However, the definition of the score grade must be a decision between artisanal fishing and marine researchers. This GIS-based identify suitable site selection technique, which includes water depth and sedimentary facies information, can be used as the fan shell production management system by supporting spatial variability decision-making in near real-time comparison of satellite image data.
Correcting Climate Model Sea Surface Temperature Simulations with Generative Adversarial Networks: Climatology, Interannual Variability, and Extremes
Authors: Wang Ya
Published: March 2024

Climate models are vital for understanding and projecting global climate. However, these models frequently suffer from biases that limit their accuracy in historical simulations and the trustworthiness of future projections. Addressing these challenges requires overcoming internal variability, hindering direct alignment between model simulations and observations and thwarting conventional supervised learning methods. Here, we employ an unsupervised Cycle-consistent Generative Adversarial Network (CycleGAN), to correct daily Sea Surface Temperature (SST) simulations from Community Earth System Model 2 (CESM2). Our results reveal that CycleGAN not only corrects climatological biases but also improves the simulation of major dynamic modes including El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole mode, as well as SST extremes. Notably, it substantially mitigates climatological SST bias, decreasing the Root Mean Square Error (RMSE) by 58%. Furthermore, it markedly refines the representation of the annual cycle in the tropical Pacific, reducing the RMSE by 31% and boosting the pattern correlation coefficient (PCC) by 34%. Intriguingly, CycleGAN effectively addresses the well-known excessive westward bias in ENSO SST anomalies, a common issue in climate models. Additionally, it augments the simulation of SST extremes, raising the PCC from 0.56 to 0.88 and lowering the RMSE from 0.5 to 0.32. This enhancement is attributed to better representations of interannual variability and variabilities at intraseasonal and weather scales. This study offers a novel approach to correct global SST simulations, and underscores its effectiveness across different time scales and primary dynamical modes.
Biogeochemistry of seep-impacted sediments at a cold-water coral site off the Vesterålen coast, Northern Norway
Authors: Argentino Claudio , Panieri Giuliana , Fallati Luca , Savini Alessandra , Barrenechea Angeles Ines , Akinselure Abidemi , Ferré Benedicte
Published: March 2024

Methane seepage in the Hola area off the coast of Vesterålen (N. Norway) has long been known for its peculiar association with cold-water coral mounds, but only recently it was possible to explore the distribution of seafloor ecosystems using a Remotely Operated Vehicle (ROV) and to conduct microhabitat-specific samplings for biogeochemical investigations. Here, we describe the results from sediment (carbon-nitrogen systematics) and pore fluid geochemistry (sulfate, dissolved inorganic carbon, methane) and interpret them in relation to the seafloor ecosystems. Microbial mats are the dominant seep-related community and form small white patches of a few tens of cm in diameter located at various distances from the coral mounds. Seep carbonates are widespread at this location and form extensive pavements. The seafloor distribution of methane bubbling and chemosynthetic communities seem controlled by fractures in the carbonates. Microbial mats are associated with intense sulfate-driven anaerobic oxidation of methane producing shallow sulfate-methane transitions coupled with highly 13C-depleted dissolved inorganic carbon in the pore water.Acknowledgments: this research was supported by Eman7 project (Research Council of Norway grant No. 320100) and AKMA project (Research Council of Norway grant No. 287869).
The fine-scale functional connectivity process in rivers influences the fish natural reproduction
Authors: deng qing , zhang xinhua , fan zhongya , yang hanjie
Published: March 2024

Dramatic environmental changes have altered the connectivity pattern of aquatic ecosystems and thus fish spawning habitats. Although connectivity processes in local riverine habitats are crucial for fish reproduction, existing connectivity simulation approaches do not allow for quantitatively describing the fine-scale connectivity structure driven by hydrogeomorphic variables. Here we proposed the fine-scale connectivity theory (FSCT) that tackled the challenge of nonlinearity issue in modeling asymmetric connectivity in water environments, aiming to clarify the mechanism of fine-scale functional connectivity structure on fish natural reproduction. The FSCT was applied to the spawning ground of the Chinese sturgeon, a critically endangered migratory fish of the utmost concern in the Yangtze River, China. Results demonstrated that our method outperformed present connectivity models with an accuracy improvement of 25.1%. This study revealed a high correlation between the connectivity of spawning habitats and spawning capacity of the Chinese sturgeon, with a value of 0.947. Our findings showed a significant decline in habitat connectivity within the Chinese sturgeon spawning ground since 2003, which was associated with the shift from an aggregated to a decentralized connectivity structure. This study can facilitate theoretical and technical support for habitat restoration and conservation efforts of endangered fish populations in dammed rivers.
Research on the transformation and immobilization mechanism of fluorine-containing phase in phosphogypsum low-carbon gel backfilling system
Authors: Wang Daolin , Zhang Qinli , Tao Yunbo
Published: March 2024

As a bulk by-product of the chemical phosphoric acid industry, phosphogypsum (PG) has not been effectively utilised because of the large number of impurities, and the large amount of stockpiled on the surface of the ground poses a potential risk of environmental pollution due to the leaching of its harmful elements. Therefore, the current consideration is to combine the bulk consumption of PG with the management of the underground mining area by cementing paste backfilling technology (CPB), so as to realise the harmless disposal of PG in the management of the mining area at the same time. However, there are several scientific problems as follows:PG has a large amount of phosphoric acid residue in the output process, which makes the pH of phosphogypsum around 2~3, and it is difficult to meet the alkaline environment requirements for cement hydration.
The poor cementing properties of PG and silicate cement lead to limited development of the strength of the PG backfilling body, and increasing the proportion of cementitious materials is bound to increase the cost of backfilling.
Although PG cemented backfiller can fix/stabilise most of the harmful elements leaching pollution, according to the preliminary experimental research, the fluorine leaching amount in the backfiller is still far more than the original groundwater quality grade standard (>2.0mg/L).
Therefore, on the basis of CaO neutralisation and modification of PG, we choose diversified active solid wastes such as steel slag and slag as backfilling cementitious materials, and use PAC or biochar as targeted fluorine fixation materials. Afterwards, we can obtain the parameters of PG backfilling ratios in line with the requirements of strength and environmental protection through a large number of experiments. The hydration and fluorine leaching mechanisms were explained by XRD, EPMA-WDS, heat of hydration test, compressive strength test and fluorine leaching test.
Climate changes driving fusuline macroevolution
Authors: Shen Shuzhong , Shi Yukun , Zhao Yingying , Zhang Shuhan , Wu Huaichun
Published: March 2024

There has been long-standing debate about what environmental factors are the main drivers of biodiversity changes. During the last hundreds of years, there are convincing signs that rising and falling CO2 and temperatures are affecting both marine and terrestrial biodiversities. However, this has been rarely tested with high-resolution biodiversity changes in deep time. It is also difficult to judge whether the current diversity loss caused by global changes is a long-term tendency or a catastrophic event because the observatory records are too short to predict the future. Fusuline foraminifers were a major group of Carboniferous through Permian marine microorganisms for ~91.8 million years (Myr) during which they experienced changes from icehouse to greenhouse climates. Here we use a high-resolution analysis of fusuline diversity with an average resolution 40 thousand years (kyr) to analyze their speciation and extinction dynamics at multiple temporal levels during this interval of major climatic shifts. This new database encompasses 1391 species from 293 published stratigraphic sections worldwide using constrained optimization method (CONOP). Our results show a symmetric diversity pattern with a peak between 295.24 Ma and 293.57 Ma in the middle of the lifespan of Fusulinida and temporally coincident with the apex of the Late Paleozoic ice age (LPIA). The shift from icehouse to greenhouse climates led to the decline of fusuline diversity. Major disruptions in fusuline diversity are found during the late Moscovian-Kasimovian interglacial event, the post-LPIA long-term warming and the middle-late Guadalupian extinction before the clade was eliminated by the end-Permian mass extinction (EPME). Each of the events of large diversity loss are linked to global warming, probably induced by massive release of greenhouse gases from intensive volcanism. The high temporal resolution also allows us to interrogate the finer-scale patterns revealing that species richness, origination, and extinction rates were paced by long-term astronomical forcing, including ~1.0 Myr obliquity and ~2.1 Myr eccentricity cycles. This highlights the substantial role of astronomically forced climate variability on the rhythms of biological evolution. Our study suggests climatic forcing of long-term changes and catastrophic events in fusuline diversity, with global cooling fueling foraminifera diversifications. This pattern is consistent with the late Cenozoic diversifications of recent foraminifera before the mid-Pliocene warming period.
The Impacts of Aerosol-physics Interactions on Numerical Weather Prediction in NOAA’s  Global Unified Forecast System (UFS)
Authors: Li Haiqin , Grell Georg , Freitas Saulo , Zhang Li , Ahmadov Ravan
Published: March 2024

A physics suite, which includes the aerosol-aware double moment Thompson-Eidhammer microphysics scheme (TH-E MP), the scale-aware and aerosol-aware Community Convective Cloud (C3) parameterization, and the MYNN-EDMF boundary layer and shallow cloud scheme, is under development at NOAA. We recently implemented a simple approach to improve the aerosol representation in the UFS. Sea salt, dust, biomass burning, and anthropogenic aerosol emissions have been embedded as CCPP-compliant subroutines. The prognostic emissions of sea-salt, and organic carbon are combined to represent the “water friendly” aerosol emission, while the prognostic emissions of dust are used to represent “ice friendly” aerosol emission for TH-E MP. With this implementation, we previously examined the aerosol indirect feedback when using the TH-E scheme in the global UFS forecast with C768 (~13km) horizontal resolution and 127 vertical levels. There are significant cloud-radiation responses to the aerosol differences, and the severely positive precipitation bias over Europe and North America was significantly alleviated when applying this aerosol emission method for indirect feedback. Here we add the indirect feedback using the C3 convective parameterization. C3 is a new collaborative development which adds several features from the currently operational SAS scheme to the Grell-Freitas parameterization. This study indicates that aerosol-physics interactions using a very simple and computationally highly efficient approach have significant impacts on the numerical weather prediction in the global UFS applications.
Estimating air temperature based on satellite surface temperature in the Metropolitan Region of São Paulo
Authors: Lustosa Rodrigo , Rocha Humberto
Published: March 2024

Air and surface temperature are among the most important variables to study the urban climate and are closely linked with thermal comfort and human health. Despite their importance, for now only surface temperature can be estimated by remote sensing, which means that the spatial variability of urban air temperature data can only be studied with a dense set of weather stations, which are expensive and do not yet have a spatial resolution as good as remote sensing. Near-surface air exchanges heat mainly with the surface which suggests that their temperatures could be estimated by each other, but as air is a fluid and moves their relationship is complex, so this estimation cannot yet be done with enough precision. This study aims to help improve the estimation of air temperature with surface temperature using the concept of footprint/source areas, which are the average surface areas that air has most interacted with before reaching the sensor at a weather station. For that, footprint areas were approximated as circles around the weather station. Then, using Landsat 5 and 8 satellites data (which passes around 10 a.m. in local solar time), average surface temperatures at different radii around 51 weather stations at the Metropolitan Region of São Paulo, Brazil, were computed. Then, the Pearson Correlation Coefficient between air and surface temperature was computed for each radius, each weather station and different periods of the year, where the radius with maximum correlation would be an approximation of the true footprint area. The average surface temperature in this area is also a better value for estimating air temperature than the surface temperature in the original Landsat data (100 and 120 metters). 
Potential evapotranspiration depends on precipitation and runoff in a catchment at the mean annual scale
Authors: Cheng Changwu , Liu Wenzhao , Li Zhi , Mu Zhaotao , Feng Hao
Published: March 2024

As a proxy for atmospheric evaporative demand, potential evapotranspiration (EP) is usually estimated by meteorologic elements such as radiation, temperature, and vapor pressure. We investigate the controlling factors of EP from the perspective of catchment water balance. Through analyzing the relationships and constraint conditions of the variables in the Budyko framework and the generalized proportionality hypothesis (GPH), we demonstrate that the mean annual EP depends on precipitation (P) and runoff (Q) and the information of EP is contained in the water balance process. Further, we propose the Budyko-based and GPH-based hydrological approaches for EP estimation and obtain the hydrological EP for the MOPEX catchments. Significant linear relationships exist between the hydrological EP and the commonly used meteorological EP, i.e., the Penman EP (EP-Pen), Priestley-Taylor EP (EP-PT), and Hargreaves-Samani EP (EP-HS). Specifically, four hydrological EP are more consistent with EP-Pen among three meteorological EP, and the Budyko-based hydrological EP are more closely related to meteorological EP than the GPH-based one. This study enriches the EP estimation methods and provides new insight into the catchment water balance from the connection between EP and hydrologic elements. (Supported by Project 41971049 of NSFC).
Westerly aridity in the western Tarim Basin driven by global cooling since the mid-Pleistocene transition
Authors: Liu Hongye , Zhang Rui , Dai Gaowen , Gu Yansheng
Published: March 2024

To explore the relationship between the global change, westerlies, and central Asian aridity, we report ~1.1 Ma local sedimentary environment changes according to high-resolution gamma ray (GR) from downhole logging, Grain size, magnetic susceptibility (MS), rubidium/strontium (Rb/Sr) ratios and total organic carbon (TOC) of an 800-m core (KT11) from the Kashgar region in the western Tarim Basin, arid zone of China. Four dominant sedimentation types, including lacustrine facies, delta facies, fluvial facies, and aeolian dunes, were identified through lithology and grain size frequency curves. The 1.1 Ma sedimentary successions experienced delta deposits with fluvial and aeolian deposits and lacustrines (1.1-0.6 Ma), alternating fluvial and aeolian facies with the occurrence of deltas and lacustrines (0.6-0.15 Ma), and aeolian facies interbedded with deltas and fluvial facies (0.15 Ma-present). Spectral analyses of the GR, MS, and Rb/Sr data reveal cycles with ~70 m, ~30 m and ~14 m wavelengths. These cycles represent ~100-kyr short-eccentricity, ~40-kyr obliquity and ~20-kyr precession frequencies, respectively and mainly are driven by orbitally forced climate change.Stepwise drying sedimentary conditions and enhanced desertification indicated by increasing Rb/Sr ratios and proportion of aeolian sands, and decreasing TOC since the past 1.1 Ma, implied intensified westerlies, likely resulted from ice volume expansion and ongoing global cooling according to geological record comparison and simulations during the Last Glacial Maximum compared to preindustrial conditions, which may have controlled the expansion of the permanent deserts in inland Asia. These persistent drying trends and intensified westerly circulation in arid regions during glacial periods after the mid-Pleistocene Transition indicated by larger amplitudes of aeolian sand proportion than prior to 0.6 Ma are similar to those in the interior monsoonal Asia, where the larger-amplitude of median grain size indicated enhanced East Asian Winter monsoon intensity and drier glacials.
Assessing source zone distribution and persistence at a trichloroethylene contaminated site
Authors: Fen Chiu-Shia , Zhuang Yu-Yang
Published: March 2024

Chlorinated solvents are prevalent and persistent contaminants, classified as dense nonaqueous phase liquids (DNAPLs) in both soil and groundwater systems.  They have been identified at numerous sites globally, significantly impacting our environment.  The subsurface distribution of DNAPLs creates a source zone with complex geometry, strongly influenced by the specific characteristics of soil textures and stratification.  Accurately defining the location and extent of DNAPL source zones at contaminated sites poses a considerable challenge due to these complexities.The aim of this study is to delineate the spatial distribution and persistence of trichloroethylene (TCE) in the subsurface for a long-term period of TCE leakage.  The studied area is situated at a factory in Taiwan.  Employing the T2VOC module within PetraSim 2019 software, we analyzed TCE movement and distribution in the subsurface over a 42-year timeframe which encompasses a 22-year period of TCE leakage and an additional 20-year period preceding remedial activities.  Field data from site investigation and remediation reports were incorporated into the analysis, encompassing information on groundwater table contours, soil layers, lithologies, permeabilities and the historical usage of TCE.  Relevant parameters, such as relative permeability, liquid residual saturation, capillary pressure and fluid saturation relationships, were determined based on literature sources.Results show that TCE infiltrates to a depth of 13 m, reaching a low permeability zone below the ground surface.  However, the site investigation only extended to a depth of 10 m (the lower bound of a high-permeability zone).  Significant TCE residuals persist in both the upper and lower layers of the high-permeability zone after the 42-year simulation period.  The dissolved phase of TCE follows the groundwater flow, extending up to 80 m downstream with notable concentration levels.  However, if considering volatilization of TCE (resulting in an 80% reduction in leakage) and an 80% reduction in the leakage area, it becomes improbable for TCE to infiltrate to the lower low-permeability layer.  This suggests a potential underestimation of the current assessment of TCE usage.  Moreover, the study underscores the influence of groundwater velocity and TCE residual saturation on the retention and persistence of TCE in the soil layers.  This emphasizes the importance of investigating hydrogeological environment and assessing TCE residuals in various soil textures at such contaminated sites.
Calculation and Analysis of Soil Erodibility Factor (K) on a Global Scale
Authors: yang Miaomiao , Yang Qinke , Zhang Keli , Pang Guowei , Wang Chunmei , Wang Lei , Long Yongqing
Published: March 2024

The soil erodibility factor (K) is the main data required for regional soil erosion investigation and mapping using soil erosion models. USLE-K, RUSLE2-K, EPIC-K and Dg-K are four widely used methods for calculating soil erodibility factor (K). However, it remains to be studied which algorithm is more suitable to calculate soil erodibility factor (K) in the global scale. While, soil erodibility factor (K) is mostly calculated based on soil physical and chemical property data, which does not involve the content of rock fragments in these algorithms. However, the amount of rock fragments and thier distribution difference have a certain influence on soil physical and chemical properties, and then affect the accuracy of the estimation of soil erodibility factor (K). In this paper, USLE-K, RUSLE2-K, EPIC-K and Dg-K algorithms were used to estimate global soil erodibility factor (K), and its spatial pattern and main controlling factors were analyzed. In this paper, the measured data of soil erodibility factor (K) were retrieved by literature search, and the measured database of K factor value was established. The rationality of the results of the above four algorithms was analyzed, and the above four algorithms for calculating K factor were modified according to the measured database of K factor. At the same time, USLE-K and RUSLE2-K algorithm are taken as an example to calculate the effect of rock fragments in the soil profile and rock fragments on the soil surface. The results showed that (1) The spatial pattern of global K factors estimated by the USLE-K, RUSLE2-K, EPIC-K and Dg-K models is similar, but the values in the K surfaces are different in some extent. (2) Comparing to 106 measured values, the mean value of estimated RUSLE2-K is the closest to the measured K factor, followed by the USLE-K algorithm and the EPIC-K algorithm, while the estimated K by Dg-K algorithm is quite different from the measured K factor. (3) The presence of rock fragment in the soil profile increased the global soil erodibility factor. The rock fragment on the soil surface reduces soil erodibility. This article made the calculation of K more complete and accurate, thereby improving the accuracy of regional soil erosion estimation. And provide the necessary scientific basis for the selection of K algorithms globally.
A laser‐based open‐path analyzer with low-temperature corrections for eddy covariance CH4 flux measurements
Authors: Wang Yin , Wang Kai , Zhang Jingting , Lu Teng , Zhou Yanze , Lin Ting-Jung
Published: March 2024

This work presents an open-path methane (CH4) analyzer (Model HT8600, HealthyPhoton Co., Ltd.) suitable for eddy covariance (EC) flux measurements based on the tunable diode laser absorption spectroscopy (TDLAS) technology. As discussed in the previous literature, EC flux measurements based on open-path analyzers are subject to temperature-correlated corrections, including the density and spectroscopic effects. The HT8600 utilizes an interband cascade laser (ICL) to probe the mid-infrared transition of CH4 at ~3221.1 nm. The chosen absorption peak has the advantage that the density and spectroscopic effects compensate for each other, resulting in low temperature-related corrections in EC flux measurements [1]. The HT8600 has a weight of ~15 kg and dimensions of 84 cm (length) and 20 cm (diameter). Multiple laser beam reflections enable an optical path length of 17 m. The total power consumption is 30 W, which lithium batteries can supply for continuous measurements. Laboratory experiments showed that the HT8600 has a noise level of 1.36 ppbv at a 10-Hz data rate. A long-term field experiment is ongoing to compare the performance of the HT8600 against another commercial open-path CH4 analyzer. We used the fluxes measured by the commercial analyzer with complete temperature corrections as the reference. Preliminary results showed that raw fluxes measured by the HT8600 achieved high consistency with the one from the commercial analyzer, which proved our initiative that the chosen absorption line is subject to low-temperature biases. As the inter-comparison is ongoing, we are collecting more field results for formal analysis of the performance of HT8600 under a wide dynamic range of temperatures. Detailed analysis of the correction factors will be presented at the conference. Meanwhile, as there is a nearby absorption line of water (H2O) at 3222.7 nm, the work extends the analyzer’s capability of measuring H2O and CH4 simultaneously, enhancing its versatility for field CH4 flux monitoring.ReferencePan, D., Gelfand, I., Tao, L., Abraha, M., Sun, K., Guo, X., Chen, J., Robertson, G. P., andZondlo, M. A. (2022). A new open-path eddy covariance method for nitrous oxide and other trace gases that minimizes temperature corrections. Global Change Biology, 28, 1446– 1457. Doi: https://doi.org/10.1111/gcb.15986.
Landslide susceptibility modeling using data-driven weights-of-evidence based random forest and radial basis function network
Authors: Zhao Xia , Chen Wei
Published: March 2024

Xiaojin County, Sichuan Province, China was selected as the study area of this paper, and twelve conditioning factors were determined according to the literature review. The spatial correlation between landslide and conditioning factors is analyzed using the weights-of-evidence (WoE) model, and the landslide susceptibility in Xiaojin county is predicted. The landslide susceptibility in this region was mainly assessment by WoE based random forest (RF) model. The radial basis function network (RBFNetwork) model was also exploited to map landslide susceptibility with the identical datasets. Finally, the landslide susceptibility maps were produced, and the comprehensive performance of the three models was quantitatively evaluated and compared by the receiver operating characteristic (ROC) curves and area under curve (AUC) values. The results show that the three models are suitable for landslide susceptibility evaluation in the study area, and the evaluation effect of the WoE model is better than that of the RF and RBF network models. More concretely, the goodness-of-fit values of the WoE, RF and RBFNetwork models in the training dataset are 0.899, 0.880 and 0.866, respectively. In terms of prediction accuracy, AUC values are 0.892, 0.874 and 0.863 respectively. Additionally, mean decrease accuracy (MDA) and means decrease Gini (MDG) are used to quantify the importance of landslide conditioning factors. Elevation, soil, distance to roads and distance to rivers are considered as the most important conditioning factors in landslide susceptibility modeling. Consequently, the study achievements in this paper have reference significance on the development and exploitation of land resources in Xiaojin County.
Dryland hydroclimatic response to large tropical volcanic eruptions during the last millennium
Authors: zhou Shangrong , Liu Fei , Dai Aiguo , Zhao Tianbao
Published: March 2024

Drylands are highly vulnerable to climate change due to their fragile ecosystems and limited ability to adapt. In contrast to the global drying after tropical volcanic eruptions shown previously, we utilize the last millennium simulations to demonstrate that large tropical volcanic eruptions can induce significant two-year hydroclimatic wetting over drylands. During this wetting period, which extends from the first to the third boreal winter after the eruption, several hydroclimatic indicators, such as self-calibrating Palmer Drought Severity Index based on the Penman-Monteith equation for potential evapotranspiration (scPDSIpm), standard precipitation evapotranspiration index (SPEI), aridity index (AI), top-10cm soil standard precipitation evapotranspiration index (SPEI), aridity index (AI), top-10cm soil drylands. The primary contribution to the wetting response is the potential evapotranspiration (PET) reduction resulting from dryland surface cooling and reduced solar radiation, as well as a weak contribution from increased precipitation. The latter is due to the wind convergence into drylands caused by slower tropical cooling. This dryland wetting response to volcanic eruptions is encouraging news for stratospheric sulfur aerosol injection, which mimics the cooling effect of volcanic eruptions for combating global warming.
Research on Sedimentary and Provenance Characteristics of the Lower Sub-member of the Third Member of Eocene Shahejie Formation in Boxing Sag, Dongying Depression, Bohai Bay Basin, China
Authors: Yan Shan , Yang Yongqiang
Published: March 2024

During the lower sub-member sedimentary period of the third member of the Shahejie Formation in the Boxing Sag, a transition from a humid to an arid climate occurred. Concurrently, the lacustrine basin experienced accelerated subsidence, leading to the development of thick-layered sand bodies caused by gravity flow. Provenance restoration plays a pivotal role in determining the location, properties, and sediment transport path of these sand bodies. This restoration was instrumental in predicting sand body distribution and holds great significance in elucidating the laws governing oil and gas accumulation.The study focused on the lower part of the third member of the Shahejie Formation in the western section of the Boxing Sag, undertaking a comprehensive investigation of sedimentary and provenance characteristics.Core wells were observed, with 50 wells having a total core length of 2547m, and over 7000 core photos were analyzed to elucidate main facies types and sedimentary landmarks in the study area. Heavy minerals and cuttings were systematically analyzed, contributing to the restoration of the provenance system. By studying typical drilling cores and logging data, the sedimentary facies of individual wells and continuous wells were determined. A sedimentary development model was established based on sand body assemblage types and spatial distribution laws. Finally, through the integration of sand dispersion system analysis, seismic attribute technology, and paleogeomorphology, a sedimentary system plan for the study area was formulated.The results show that the provenance area can be categorized into three types based on rock types and heavy mineral characteristics in the provenance area: the northwest source area, the western provenance area, and the southern provenance area. The northwestern, western, and southern provenance areas exhibited stable development during the study period, with heavy mineral assemblages remaining consistent on the horizontal development. Meanwhile, The turbidity fan in the study area primarily originated from the northwest provenance area, with minimal influence from the western and southern provenance areas on the cross-section. The characteristics of the lower provenance system of the third member of the Shahejie Formation in the Boxing Sag were clarified. Main sand body types and facies markers were summarized, leading to the establishment of an accurate sedimentary development model.To sum up, this research aims to elucidate the accumulation laws of oil and gas reservoirs, providing a theoretical and data foundation for the identification and exploration of favorable areas, ultimately minimizing exploration risks.