bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupled Conditional Nonlinear Optimal Perturbations and its applications to ENSO ensemble forecasts
Authors: Lei Hu , Wansuo Duan , Rong Feng
Published: March 2024

    Considering the limitations of current ensemble forecasting initial perturbation methods in describing the interactions among various spheres of the Earth system, this study proposes a new method called the Coupled Conditional Nonlinear Optimal Perturbation (C-CNOP), which incorporates the effect of muti-sphere coupling uncertainties. By applying the C-CNOP method to ensemble forecasting of El Niño-Southern Oscillation (ENSO), which is a typical tropical Pacific ocean-atmosphere coupling phenomenon, the study demonstrates that the C-CNOP method can generate coupled initial perturbations (CPs) that much appropriately consider the effect of initial uncertainties of coupled ocean-atmosphere system. It is revealed that the CPs significantly improve ENSO ensemble-mean forecast skill of the time variability of Niño3.4 sea surface temperature anomalies (SSTAs) and the spatial variability of ENSO mature-phase SSTA. Particularly, despite the weakest ocean-atmosphere coupling in the tropical Pacific during the boreal spring and summer, CPs can still capture the uncertainties of the weak coupling when predicting from these seasons, which suppresses the rapidly growing of ENSO prediction errors caused by the strongest ocean-atmosphere coupling instability during these seasons, and thus effectively extends the lead time of ENSO forecasting. Hence, the C-CNOP method is an approach to produce ensemble forecasting initial perturbation that can consider the effect of initial coupling uncertainties much appropriately, which is expected to play an important role in future Earth climate system predictions with further research.
Influence of convectively coupled MRG waves on the north-east monsoon rainfall characteristics over south India.
Authors: Mamidi Kartheek , Narayanan Nithya , Mathew Vincent , Kumar S Siji
Published: March 2024

The northeast (NE) monsoon contributes considerable annual rainfall over southern peninsular India. Here, an attempt has been made to evaluate the role of convectively coupled mixed Rossby-Gravity (MRG) waves on the variabilities of NE monsoon rainfall. The gridded rainfall data from 1980 to 2021 from the India Meteorological Department shows large interannual variability in NE monsoon rainfall over southern peninsular India. Wavelet analysis of outgoing longwave radiation (OLR) data shows the dominance of short-period waves over the equatorial Indian Ocean during the above-normal NE monsoon rainfall years compared to below-normal rainfall years. The space-time spectral analysis further confirms the dominance of the short-period westward propagating convectively coupled equatorial waves (CCEW) during above-normal excess NE monsoon rainfall years. In contrast, the eastward component of CCEWs dominates the deficit rainfall years. Further, the empirical orthogonal function (EOF) analysis of OLR filtered for MRG wave shows that the first two leading modes explain more than 14% of variability over the Indian Ocean domain. Moreover, the vertically integrated moisture flux convergence indicates the role of MRG wave in triggering the extreme rainfall over southern peninsular India and also offer favourable condition for the formation of cyclogenesis and, thereby, inducing heavy rainfall over the South Indian domain. Thus, the results suggest that the westward propagating MRG waves play a seminal role in modulating the NE monsoon rainfall over southern peninsular India.
Keywords: mixed Rossby-Gravity wave, north-east monsoon, extreme precipitation
Cleaner air in the future will exacerbate the risk of compound flood-heatwave extremes in the Northern Hemisphere
Authors: Wang Zhili , Li Yingfang , Lei Yadong , Yu Xiaochao
Published: March 2024

The reductions in non-methane short-lived climate forcer (SLCF) emissions to improve air quality can contribute to additional warming of the climate system in the short term, thereby increasing the risk of extreme climate events. In this study, we quantitatively investigated the changes in future (2031-2050 versus 1995-2014) compound flood-heat wave extremes (CFHEs) and the resulting population exposure in the Northern Hemisphere (NH) due to non-methane SLCF reductions by using multi-model ensemble simulations under two future scenarios from the Aerosol and Chemistry Model Intercomparison Project. These two future scenarios share the same greenhouse gas (GHG) emissions but have weak (SSP3-7.0) versus strong (SSP3-7.0-lowNTCF) levels of air quality control measures. The results showed that reductions in non-methane SLCF emissions by 2050 will result in a 6% increase in grid exposure to CFHEs in the NH relative to the period 1995-2014. During the period 2031-2050, the frequency of CFHEs across the NH will increase by 2.9 events/decade due to non-methane SLCF reductions. The increases in CFHE frequency will be more pronounced in East Asia, South Asia, Siberia, and northern and eastern North America, reaching 4.8±2.0, 4.2±1.6, 3.5±0.9, 4.1±0.5, and 3.1±1.3 events/decade, respectively. At the regional scale, the sensitivity of CFHE frequency to non-methane SLCF mitigation was 1.2-1.9 times higher than that to GHG forcing. Future reductions in non-methane SLCFs will result in NH-averaged increases in population exposure to CFHEs of (5.0 ± 2.0) × 105 person-events in the period 2031-2050, contributing to increases in population exposure of 13.2-25.9% in different subregions. This study emphasizes the importance of considering the impacts of cleaner air in future responses to compound extreme climate events and corresponding societal planning.
Spatiotemporal analysis of paleofloods in the Negev region (Israel): insights into past climate
Authors: Zohar Motti
Published: March 2024

The climatic conditions of the Negev Desert (Israel) during Late Antiquity (circa 300 - 700 CE) hold considerable scholarly interest, given their potential implications for understanding past human societies and environmental dynamics. Reconstructing the climatic conditions of the Negev during this period enriches our knowledge of historical climate variability in this arid region. It provides crucial insights into the challenges faced by ancient societies in adapting to climatic changes and enhances our understanding of human-environment interactions. However, the scarcity of reports and evidence due to the remoteness of the Negev poses challenges. This study conducts a comprehensive review of historical, archaeological, natural, and botanical proxies to extract information about agricultural practices, water management systems, settlement patterns, land-use changes, and societal adaptations to evolving environmental conditions. Additionally, a spatiotemporal analysis of paleofloods is implemented and compared with the existing sources. The spatial findings reveal that the information gleaned from this multidisciplinary approach may contribute novel insights into the climatic context of the Negev during Late Antiquity.
Assessing the Impacts of Excessive Groundwater Extraction in the Vietnamese Mekong Delta and proposing Aquifer Recharge  Management Solutions
Authors: Tran Trung Dang , Kim Hung Nguyen , Steinel Anke , Hue Nguyen Thanh Kim , Quyen Pham Ba , Hoa Nguyen Thi , Hoan Hoang Van
Published: March 2024

The Vietnamese Mekong Delta (VMD) is one of the largest economic centers in southern Vietnam, home to approximately 18 million inhabitants. The geological composition of the region encompasses seven aquifers namely Holocene (qh), Middle-Pleistocene (qp3, qp2-3, qp1), Pliocene (n22, n21) and Upper-Miocene (n13) characterized by porous formations and fractures, facilitating the percolation and retention of groundwater. In the region, groundwater is a vital role as a fundamental water resource, serving essential functions in domestic, agricultural, and industrial domains. However, the intensive extraction of groundwater leads to several negative impacts, including reduction of groundwater level, saline water intrusion into the groundwater, and the potential threat of land subsidence in several locations.
This study aims to quantitatively assess the future change in groundwater level in VMD through the utilization of a FEFLOW forecasting model consideing several climate change groundwater exploitation scenarios. The results reveals a substantial decline in groundwater levels by the year 2100, ranging from 15 m to 25 m in the aquifers qp2-3, qp3, n22, n21, n13 and a deeper more than 35 m in the aquifer qp1. Due to the influence of the groundwater extraction process in the main aquifer, the groundwater level will be lowered, forming lower funnel-shaped depressions and a subsequent shift of saline boundary in the aquifer system.  The findings also underscore the occurrence of varying degrees of saline intrusion across all six aquifers, observed in both the Pleistocene (qp) and Neogene (n) aquifers. To mitigate the risks associated with saltwater intrusion, it is recommended to strategically plan the placement of water extraction wells at a considerable distance from the saline boundary. Additionally, it is advisable to implement measures focused on artificial replenishment, the development of water sources, and the promotion of surface water utilization, especially in regions experiencing water scarcity.
An Unstructured Mesh Generation Tool for Efficient High-Resolution Representation of Spatial Heterogeneity in Land Surface Models
Authors: Wei Zhongwang , Fan Hanwen
Published: March 2024

This study develops an unstructured mesh generation tool for land surface modeling using a multi-scale hexagon discrete grid. The tool can automatically determine the required grid resolution for different regions based on multi-objective criteria such as elevation, slope, land cover, and land use. The refined unstructured meshes demonstrate significant enhancement in the representation of spatial heterogeneity. The tool is coupled with the Common Land Model (CoLM) to enable land surface simulations using unstructured grids. Evaluations focused on runoff, river discharge, and inundation indicate improved model performance compared to traditional grid-based CoLM simulations under the same computational cost constraints. This tool provides new capabilities for more efficiently capturing localized land surface processes and extreme events.
Revealing the response of evapotranspiration and water use efficiency to vegetation changes in different types of urban green spaces
Authors: Shao Rui
Published: March 2024

The quantification of urban water‒carbon change is critical to our ability to assess urban water resource effectiveness and quantify urban ecological processes. In this study, we used Sentinel-2 data combined with the PT‒JPLim and analytical water use efficiency (WUE) models to simulate monthly urban evapotranspiration (ET) with a spatial resolution of 10×10 m, analyzing the WUE and ET partitioning in the main urban area of Beijing from 2016 to 2021. Verification of modeled ET based on two flux towers showed that the PT‒JPLim model performed well (Daxing: R2 = 0.84, RMSE = 16.76 mm/month; Miyun: R2 = 0.83, RMSE = 22.10 mm/month). The annual mean ET and WUE in the main urban area of Beijing were 497 mm and 0.63 gC mm−1 H2O, respectively. The carbon sequestration rate (i.e., gross primary productivity) in the main urban area of Beijing significantly increased (0.074 gC m−2 d−1 yr−1), and the proportion of water utilization (i.e., ET) decreased (−19.87 mm yr−1) during the study period, which was reflected in an increase in WUE (0.029 gC mm−1 H2O yr−1). We extracted the ET and WUE of four urban green space types (park, square, residential, and scenic green spaces) based on point of interest data. Residential green space showed the largest increases in ET (6.2%) and WUE (30%) when influenced by a 25% increase in vegetation. We projected the ET and WUE of Beijing for the period 2022‒2100 based on CMIP6. The vegetation WUE (0.0512 g C mm−1 H2O yr−1) in Beijing was projected to increase by the greatest amount under a medium forcing scenario, whereas the water consumption (0.51 mm yr−1) showed a lesser increase. This study offers new insights into the refined simulation of urban ET and WUE, enabling the quantification of water consumption and carbon sequestration processes in urban green spaces.
A persistent weakening of the winter monsoon during the last 580 kyr
Authors: Kumar Gavendra , Saraswat Rajeev
Published: March 2024

The Indian monsoon is a complex climatic phenomenon characterized by seasonal shifts in winds, rainfall, and ocean currents. The monsoon strongly influence the climate and ecosystems of the region. The reconstruction of the past monsoon variations can help to understand the potential drivers of the monsoon. The eastern Arabian Sea is a dynamic marine region that is influenced by various oceanographic processes, including the advection of upwelled water from the western Arabian Sea during the summer and convective mixing during the winter season. We used the relative abundance of planktic foraminifera from the sediments drilled during the International Ocean Discovery Program Expedition 355 Site U1457 to reconstruct the summer and winter monsoon variability during the last 580 kyr. Globigerinita glutinata was the most abundant species, prior to Marine Isotopic Stage (MIS) 12. Its relative abundance decreased post MIS12, suggesting weakened winter monsoon. We further report that the relative abundance of G. glutinata was high during the glacial cycles as compared to the interglacials, suggesting strengthened winter monsoon induced increased convective mixing in the eastern Arabian Sea. The relative abundance of Globigerina bulloides was higher during interglacials, suggesting intensified summer monsoon. From the cumulative relative abundance of summer and winter monsoon assemblages, it is evident that the winter monsoon consistently weakened during the last 580 kyr.
Formation of long-lasting inactive and active multiple tropical cyclone events in the western North Pacific
Authors: Chen Lilan , Gao Jianyun , Li Tim
Published: March 2024

Long-lasting inactive and active multiple tropical cyclone (MTC) events in the western North Pacific (WNP) during July-August 1982-2020 were investigated. It is found that the significant difference between the inactive and active events lies on large-scale circulation conditions and tropical SST anomalies in the Pacific and Indian Ocean. A negative phase of the Pacific Meridional Mode (PMM), an Indian ocean warming and a local suppressed convective phase are associated with the long-lasting inactive MTC events, and vice versa. A further diagnosis of the environmental parameters showed that dynamic parameters such as mid-level vertical motion and the upper-level divergence and thermodynamic parameters such as vertically integrated water vapor content and low-level specific humidity play important roles in regulating the inactive and active MTC events. A separation of interannual and intraseasonal components indicates that the extreme MTC events are influenced by both the timescale motions. While the former is primarily through the SSTA-induced low-level anticyclonic and descent anomalies, the latter is via the fluctuation of the boreal summer atmospheric intraseasonal oscillation.
Influence of Impeller Design Parameters and Manufacturing Process on the Centrifugal Pump Energy Efficiency
Authors: Kord Mahin Sima , Hajizadeh Mostafa
Published: March 2024

Impellers can be considered as an the most important part of a centrifugal pump that directly affects system durability and performance. Centrifugal pumps are widely used around the world to ease daily life, and industries in particular oil and gas sections. Design parameters such as geometry, and manufacturing process have prime importance to guarantee the pump efficiency.  Conventional manufacturing processes such as casting and milling in particular Computer Numerical Control (CNC) milling are still today widespread process to produce an impeller that generally are followed by other surface finishing methods. But complex geometries can not be easily produced by such processes, therefore advanced digital methods like additive manufacturing process (AM) newly are applied to improve efficiency in terms of materials scrap, time and operator costs.  As a result, the use of this technology can eventually be seen as the key to developing high-performance rotor components. Considering a complex impeller geometry, it poses remarkable challenges to the engineers in order to produce it with the best possible dimensional accuracy and surface quality, and to reduce manufacturing production times. impellers are composed of blades and a hub, to transform kinetic energy to hydraulic one. The vast number of scientific works have been devoted to be concentrated on efficient tool-path generation strategies or optimization of the milling strategies in respect to various indicators. This study is aimed to study the effects of geometrical parameters and additive manufacturing processes to improve centrifugal pump efficiency in particular in terms of energy saving. Experimental and numerical simulation have been revealed that AM processes are the most promised methods to be substituted by conventional processes. Topology optimization and selective laser melting were utilized to digitalize the process and examine in detail the contribution of influential parameters. The results provide evidence that optimum design of impeller caused reduction of energy consumption by 17%.
Pore-throat structure and fractal characteristics of tight sandstone: A case study in Yanchang Formation, Southeast Ordos Basin
Authors: Zhang Huanmeng
Published: March 2024

The complex pore throat structure of tight sandstone reservoirs increases the difficulty of reservoir exploration and development, and becomes a key factor affecting oil and gas charging and reservoir oil content control. Quantitative evaluation and characterisation of the pore-throat structure is also important for maintaining and improving oil recovery. In order to determine the microstructure of pore throats, a series of experiments such as casting thin section, scanning electron microscopy, X-ray-rock diffraction experiment and high pressure mercury injection (HPMI) were carried out on the tight oil sandstone samples of the Chang 6 member in the south-eastern Ordos Basin, China. The relationship between each factor and pore throat complexity was investigated using factors such as reservoir physical properties, pore throat characteristic parameters and mineral composition.
The results indicate that the main pore types of the sample are intergranular pores, feldspar dissolved pores, intergranular dissolved pores and micro-cracks. Meanwhile, the pore throat structure of each sample was identified as large pores and small pores by combining the result of HPMI with fractal theory. The small pores of Chang 6 tight reservoirs are the dominant factor affecting the pore throat structure. The development of small pores positively influences the maximum pore radius, median radius, sorting coefficient, maximum mercury saturation and mercury recovery efficiency, indicating that with the development of small pores, the properties of percolation, storage, pore throat connectivity and oil recovery would become better. Fractal theory was used to quantitatively characterise the complex and irregular pore throat structure of the reservoir. The total fractal dimension D ranged from 2.3601~2.7403 with an average of 2.5722. The average fractal dimension D1 was 2.8094 and the average fractal dimension D2 was lower than D1 with an average of 2.5325, indicating the complex structure and strong heterogeneity of the former. D2 has better correlations with the pore throat structure parameters than D1. The heterogeneity and surface roughness of small pores mainly influence the properties of the pore throat structure, especially the percolation and storage space of the reservoir. The development of small pores is a major factor influencing the pore throat structure of the Chang 6 tight oil sandstone. The fractal characteristic of small pores reflects how well the pore throat structure is suited for exploration and development of Chang 6 tight oil.
Typhoon disaster chain risk assessment: A model based on disaster hazard and carrier vulnerability
Authors: Wang Ting , Tan Xinru
Published: March 2024

The disaster chain caused by strong typhoons has caused huge social economy and ecological environment impact on coastal areas. In this study, a special risk assessment model is proposed for the typhoon-storm tide-flood-embankment disaster chain based on its disaster mechanism and chain disaster law. The proposed model is developed to reflect both the disaster hazard which based on the probability distribution function of Bayesian network, and the carrier vulnerability which based on the evaluation index system. The model has been successfully applied in the coastal cities of Guangdong Province, China, and the disaster chain risk under three typical typhoon scenarios has been simulated. The results reveal that the risk distribution of different disasters caused by typhoons is different due to the different decisive factors. For storm tide disaster, the highest risk is mainly in the coastal city of Zhuhai, and as the influence of sea level increase caused by typhoon gradually weakens from coastal area to inland, the disaster chain risk gradually weakens from coastal to inland. For flood disaster, the highest risk is mainly distributed in the economically developed and densely populated Foshan City due to its low carrier vulnerability. For embankment disaster, the highest risk is mainly distributed in Zhongshan City due to its low design grade of dike, indicating that the condition of water conservancy project is an important factor in determining whether the dike failure or not. The research results are of great significance for coping with typhoon disaster chain in coastal areas, and have certain reference value for identifying the chain risk transmission of typhoon disaster. 
Detrital zircon characteristics of Paleoproterozoic-Ordovician in the Olongbuluke Terrane: implication for the affinity of Olongbuluke Terrane and the closure of the Proto-Tethys Ocean
Authors: Wang Teng , Zhou Yanan , Wu Hanning
Published: March 2024

The Qilian-Qaidam Orogenic Belt (QQOB) belongs to the western Central China Orogenic Belt (CCOB), recording a nearly complete evolutionary history of the South Qilian and North Qaidam Ocean (branches of the Proto-Tethyan Ocean). However, some debates still exist, such as the affinity and amalgamation processes of microblocks in the western CCOB and the closure time of the South Qilian and North Qaidam Oceans. The Olongbuluke Terrane (OLT), as a connecting area located at the central of QQOB, where Precambrian to Paleozoic sedimentary successions are well developed, offers a unique window to address the tectonic history of the South Qilian and North Qaidam Ocean basins. In this study, detrital zircon U–Pb ages combined with ophiolitic, magmatic and high-pressure to ultrahigh-pressure metamorphic records and field investigations, indicate that the OLT was part of a passive continental margin during the early Paleozoic and there was still a microblock, named the North Qaidam Terrane (NQT), between the Qaidam Block (QB) and the OLT. Considering the regional geology, at ca. 517 Ma, an obvious provenance change occurs in the OLT, inferring the collision between the OLT and NQT. Subsequently, the North Qaidam Oceanic plate subducted to the NQT, and the North Qaidam Ocean closed at ca. 450 Ma. The similar detrital zircon U–Pb age spectra of simultaneous deposit flysch sequences between the Shihuigou Formation in the OLT and the Balonggonggaer Formation in the South Qilian Accretionary Belt indicates the onset of collision between the OLT and CQT at ca. 458 Ma. The detrital zircon U–Pb age spectra of microblocks from the early Paleozoic strata of the northern Tibetan Plateau shared a North Indian affinity, indicating that the closure of the Proto-Tethyan Ocean may relate to the formation of the Gondwana landmass. Until the late Devonian to early Carboniferous period, with the opening of the Paleo-Tethyan Ocean, the QB, OLT and CQT drifted as an entirety from the Gondwana landmass.
An Iterative Algorithm for Predicting Seafloor Topography from Satellite Altimetry Gravity Data
Authors: An Bang , Yu Jinhai
Published: March 2024

As high-resolution global coverage cannot easily be achieved by direct bathymetry, the use of gravity data is an alternative method to predict seafloor topography. Currently, the commonly used algorithms for predicting seafloor topography are mainly based on the approximate linear relationship between topography and gravity data. In actual application, it is also necessary to process the corresponding data according to some empirical methods, which can cause uncertainty in predicting topography. We established analytical observation equations between the gravity data and topography, and obtained the corresponding iterative solving method based on the least square method after linearizing the equations. Furthermore, the regularization method and piecewise bilinear interpolation function are introduced into the observation equations to effectively suppress the high-frequency effect of the boundary sea region and the low-frequency effect of the far sea region. Finally, the seafloor topography beneath two sea region (117.25°-118.25° E, 13.85°-14.85° N), (112.6-113.25° E,11.0-11.65° N) in the South China Sea are predicted as an actual application, where gravity data of the study area with a resolution of 1′×1′ is from the DTU17 model. Comparing the prediction results with the data of ship soundings from the National Geophysical Data Center (NGDC), the root-mean-square (RMS) error and relative error can be up to 127.4 m(gravity anomaly) and 109m(vertical gravity gradient anomaly). The bathymetry predicted from gravity could be combined with ship soundings for the next generation of bathymetry map.
Impact of Initial Soil Conditions on Soil Hydrothermal and Surface Energy Fluxes in the Permafrost Region of the Tibetan Plateau
Authors: Luo Siqiong , Chen Zihang
Published: March 2024

Accurate initial soil conditions play a crucial role in simulating soil hydrothermal and surface energy fluxes in land surface process modeling. This study emphasized the influence of the initial soil temperature (ST) and soil moisture (SM) conditions on a land surface energy and water simulation in the permafrost region in the Tibetan Plateau (TP) using the Community Land Model version 5.0 (CLM5.0). The results indicate that the default initial schemes for ST and SM in CLM5.0 were simplistic, and inaccurately represented the soil characteristics of permafrost in the TP which led to underestimating ST during the freezing period while overestimating ST and underestimating SLW during the thawing period at the XDT site. Applying the long-term spin-up method to obtain initial soil conditions has only led to limited improvement in simulating soil hydrothermal and surface energy fluxes. The modified initial soil schemes proposed in this study comprehensively incorporate the characteristics of permafrost, which coexists with soil liquid water (SLW), and soil ice (SI) when the ST is below freezing temperature, effectively enhancing the accuracy of the simulated soil hydrothermal and surface energy fluxes. Consequently, the modified initial soil schemes greatly improved upon the results achieved through the long-term spin-up method. Three modified initial soil schemes experiments resulted in a 64%, 88%, and 77% reduction in the average mean bias error (MBE) of ST, and a 13%, 21%, and 19% reduction in the average root-meansquare error (RMSE) of SLW compared to the default simulation results. Also, the average MBE of net radiation was reduced by 7%, 22%, and 21%.
Contact metamorphism, PT conditions and model of the emplacement of the High Moulouya batholith (Moroccan Variscan Meseta). Insights from thermodynamic and gravity modelling
Authors: Elabouyi Mustapha , Driouch Youssef , Dahire Mohamed , Ntarmouchant Ahmed , Jeddi El Mehdi , Mali Brahim , Laguenini Fouzia , Belkasmi Mohammed
Published: March 2024

In the Moroccan Eastern Meseta, the High Moulouya Batholith (HMB), which spans an area of approximately 2400 km2, is partially hidden by the Meso-Cenozoic cover. The HMB was emplaced in Cambro-Ordovician metasedimentary rocks that had undergone greenschist facies metamorphism (Chl+Mus+Qtz+Pl+Kfs). These hosting rocks were then affected by HT-BP superimposed contact metamorphism linked to HMB emplacement. Four metamorphic zones were identified, delineating four isograds corresponding to four main metamorphic reactions. These zones include the biotite zone, cordierite zone, andalusite zone, and sillimanite zone. 
The biotite zone exhibits a mineral assemblage of Bt+Mus+Chl+FK+Qtz (±Pl ± Grt), marking the introduction of biotite through the discontinuous monovariant reaction: Chl+Qtz+FK+H2O=Bt+Mus . In the cordierite zone, the composition includes Bt+Mus+Crd+Chl+FK+Qtz (±Pl), and the reaction leading to Crd formation is: Chl+Bt+Mus+Qtz = Crd+FK+H2O. The successive development of aluminum silicates characterizes the andalusite and sillimanite zones, each associated with specific isograds corresponding to the following reactions: (Sill)+Qtz+H2O, Mus+Qtz=FK+And (Sill)+H2O, and/or And=Sill.
The obtained results, using pseudosection modelling as well as petrogenetic grid calculations, allow to precise better the HMB emplacement PT conditions. Biotite appears at a temperature of 400°C, cordierite at 500 to 520°C and andalusite at 580 to 600°C. The stability field of the andalusite-sillimanite paragenesis allows constrains the pressure at 2.6 to 2.9 Kb, which is considered constant for the entire metamorphic aureole. Therefore, the granitoids of the HMB were emplaced at a depth of 8.5 to 9.5 km, developing a contact aureole for temperatures ranging from 400 to 625°C. Moreover, 2D gravity modelling revealed that the HMB has a laccolithic shape with a thickness ranging from 3 to 5 km. The presence of numerous feeders suggests that the emplacement of the HMB occurred through a dyking process.
Upscaling porosity and permeability in core plug sample from core plugs simulations using machine learning methods
Authors: Jouini Mohamed Soufiane , Bouchaala Fateh
Published: March 2024

Characterizing accurately rock properties at core scale is critical for reservoir scale modeling. This step is especially complex when dealing with carbonate rocks because of their inherent heterogeneities at several length scales. The deposition and diagenesis processes result in diverse pore-shaped geometries, significantly influencing petrophysical properties. Notably, two core plug samples taken from adjacent locations within a carbonate core may exhibit substantial differences in rock properties. While standard core analysis methods offer precise experimental measurements in the laboratory, they fail to consider the pore-scale variability within core plug samples. Digital rock physics (DRP) emerges as an approach aiming to characterize rock properties at the pore scale through the utilization of X-ray micro-tomography and numerical simulation methods. DRP has been widely employed to estimate various rock properties, including porosity, permeability, and elastic moduli, in both siliciclastics and carbonate rocks. However, a well-defined workflow for numerically characterizing rock properties in carbonates is currently absent. This study introduces a novel multiscale method for simulating permeability and porosity in heterogeneous carbonate samples using 3D X-ray computed tomography images. The unique aspect of our approach lies in incorporating a quantitative description of heterogeneity through texture classification using machine learning. The results of rock texture classification are then utilized to scale up simulations of rock properties from a fine to a coarse scale. The fine-scale properties are examined using the lattice Boltzmann method, while a Darcy-scale flow simulator is applied to estimate coarse-scale properties. In addition, due to the critical role played by petrophysical properties at fine scale, we employ a 3D printing technique to experimentally validate the numerical simulations. Lastly, we demonstrate the application of our proposed approach on two carbonate samples from a Middle East carbonate oilfield reservoir.
Nutrient availability and stoichiometry mediate microbial effects on soil carbon sequestration in tropical forests
Authors: Liu Zhanfeng , Mou Zhijian
Published: March 2024

The persistence of soil organic carbon (SOC) is primarily driven by microbial metabolic activities; however, how microbial effects on SOC sequestration are affected by soil nutrient status remains unclear. Here, we conducted a one-year-long in situ soil incubation experiment using mesh bags (with a mesh size of 38 µm, allowing bacterial colonization and fungal hyphal penetration while preventing root penetration). This experiment involved incubating fertile sugarcane soil and infertile sand across an elevational gradient, characterized by diverse climatic and biotic conditions within a tropical forest. Biomarkers, such as phospholipid fatty acids, carbon-, nitrogen-, and phosphorus-acquiring hydrolases, glomalin-related proteins, and amino sugars, were measured to characterize the production and accumulation of microbial biomass, exo-enzymes, extracellular glycoproteins, and microbial necromass. These measurements aimed to elucidate their respective contribution to the sequestration of SOC. We found that Gram-negative bacteria dominated the microbial community composition in fertile soil, and the higher nutrient availability was related to the production and accumulation of microbial necromass via promoting microbial biomass turnover, thus enhancing the accumulation of SOC in fertile soil. This process was negatively associated with phosphorus availability and carbon- and phosphorus-acquiring enzyme activities in fertile soil. In contrast, the SOC accumulation was positively correlated with nitrogen availability and stoichiometry (including C:N and C:P), as well as moisture content in infertile sand. However, more resources were preferentially allocated to stress-tolerant fungi and Gram-positive bacteria under nutrient deficiency in infertile sand used for microbial biomass maintenance, nutrient acquisition, and environmental adaption which further aggravated the consumption of SOC, resulting in SOC loss after one year of field incubation. Our results suggest that microbial effects on SOC persistence are highly context-dependent and nutrient availability-induced changes in microbial communities and microbial resource-allocation strategies are key processes for understanding and predicting the fate of carbon in tropical forest soils.
Channel-Shoal Hydrodynamic Interaction in Partially Stratified Estuaries: A Barotropic Versus Baroclinic Perspective
Authors: Zhou Jian , Chen Yuqi , Zhang Wenzhe
Published: March 2024

Drowned-river estuaries are usually composed of a deep channel laterally bounded by shallow shoals. The channel-shoal interface in partially stratified estuaries is a dynamically important region where complicated lateral circulations can develop. Despite their relatively smaller magnitude with respect to the along-channel currents, lateral flows play an important role in both longitudinal and lateral dynamics of estuaries. In a previous study by Zhou et al. (Journal of Geophysical Research: Oceans, vol. 125, e2020JC016135) that focuses on channel-shoal interaction with only baroclinic forcing, lateral barotropic forcing arising from the change of water surface elevation was neglected by making a rigid-lid assumption. This limitation may be important especially on the shallow shoal, where strong lateral barotropic transport could be observed when the shoal is ventilated at low water. In this study, three-dimensional idealized numerical simulations were performed to investigate the coaction of barotropic and baroclinic forcings as a driver of channel-shoal hydrodynamic interaction in partially stratified estuaries. It was found that the shoalward advection of highly-salinity water mass energizes shoal water away from the channel-shoal interface. On the shallow shoals, barotropic and baroclinic lateral circulations show strong spatiotemporal correlativity, with their relative importance determined by the strengths of tidal and river forcing. Relevance of the findings from the idealized simulations to the hydrodynamics of a realistic channel-shoal estuary was also provided.
Coupled conditional nonlinear optimal perturbations and their applications to ENSO ensemble forecasts
Authors: Duan Wansuo , Hu Lei , Feng Rong
Published: March 2024

There exist limitations of existing ensemble forecasting initial perturbation methods in describing the interactions between various spheres of the Earth system. In this study, a new method is proposed, namely, the coupled conditional nonlinear optimal perturbation (C-CNOP) method, which incorporates the effect of the initial uncertainty in multisphere coupling. The El Niño-Southern Oscillation (ENSO) is a typical tropical Pacific ocean–atmosphere coupling phenomenon. The C-CNOP method is applied to ensemble forecasting of ENSO, It is demonstrated that the C-CNOP method can generate coupled initial perturbations (CPs) that appropriately consider the effect of ocean–atmosphere coupling uncertainty for ENSO. The results reveal that the generated CPs effectively improve the ability of ENSO ensemble-mean forecasts in both the temporal variability in Niño3.4 sea surface temperature anomalies (SSTAs) and the spatial variability in ENSO mature-phase SSTAs. In particular, despite the weak ocean–atmosphere coupling in the tropical Pacific occurring during the boreal spring and summer, CPs still capture the uncertainties associated with weak coupling when predicting on the basis of these seasons. This performance of CPs significantly suppresses the rapid increase in ENSO prediction errors due to the high ocean–atmosphere coupling instability during these seasons, and thus effectively extends the lead time of ENSO forecasting. Hence, the C-CNOP method is a suitable initial perturbation approach for ensemble forecasting that can consider the effect of the initial coupling uncertainties. It is expected that the C-CNOP method plays a significant role in future Earth climate system predictions.
A workflow solution for coastal hydrodynamic and water quality modelling using Delft3D Flexible Mesh
Authors: Backeberg Björn , Meszaros Lőrinc , Luna-Valero Sebastian
Published: March 2024

Increasingly, high resolution coastal hydrodynamic and water quality models are executed on distributed, heterogenous compute and data infrastructures. Working on these infrastructures presents challenges associated with (1) accessing the requisite model input data, (2) preprocessing the input data so that the models can ingest them, (3) compiling the model for different computing infrastructures, and (4) running the models at scale. These challenges are bottlenecks for setting up and running modelling systems in an interoperable and reproducible way. Here we present a workflow solution for Delft3D Flexible Mesh that was developed for a federated compute and data infrastructure to overcome some of these challenges. The workflow solution is based on snakemake which is a Python, rule-based workflow management system that facilitates creating reproducible and scalable analyses. Snakemake integrates with the package manager Conda and the container engine Singularity and docker such that defining the software stack becomes part of the workflow itself, supporting various operating systems for reproducibility and portability. We demonstrate how it can be used to download the requisite model input data and prepare them for running Delft3D Flexible Mesh on heterogenous computing infrastructures. The workflow ensures reproducibility by clearly documenting the dependencies between the workflow components. Snakemake is able to automatically parallelise the workflow execution by efficiently using available resources and easily adapts from single-core workstations to large clusters, supporting batch systems, and cloud platforms. In the future our approach will facilitate improved automation for coastal hydrodynamic and water quality modelling and forecasting supporting the globally applicable, locally relevant paradigm necessary for implementing a digital twin of the Earth.
Promotion of soil fauna and its services through adapted management strategies in wheat and potato cultivation.
Authors: Schrader Stefan , van Capelle Christine , Bind David-Alexander
Published: March 2024

As part of the Horizon 2020 EU project SoildiverAgro, innovative management strategies are being developed to promote soil biodiversity in European agricultural landscapes, increase ecosystem services and thus counteract the current trend of biodiversity loss. These adapted management measures are intended to improve the long-term yield capacity, stability and resilience of agroecosystems, reduce the need for external inputs and contribute to sustainable agricultural production on healthy soils.
In order to investigate and assess the potential of different management practices to achieve these objectives, 15 case studies were conducted in six pedoclimatic regions of the EU over the period 2021 to 2023. In the continental region, two case studies were carried out in conventional wheat cultivation and one in organic potato production. In these three studies, the effects of extensification (reduction in the use of plant protection products) and diversification (cultivation of undersown crops) were studied. In addition to soil and plant parameters, the effects on the abundance and diversity of lumbricids and microarthropods (collembolans and mites) as well as their bioregulatory potential with regard to the suppression of phytopathogenic fungi (Fusarium and Alternaria) and the degradation of their mycotoxins (e.g. deoxynivalenol and zearalenone) were analysed. This ecosystem service is essential for maintaining plant and soil health and can help to reduce the use of fungicides in the long term.
The results of the case studies show that in particular diversification through undersown crops promotes abundance and diversity of soil animals. Under organic potato cultivation with ploughing positive effects on microarthropods and soil parameters occurs in the short term i.e. in the first year of the study. Under conventional ploughless wheat cultivation the system responds with delay. In this case, a promotion of abundance, diversity and performance of the soil fauna (lumbricids, collembolans, mites) through diversification is found in the following vegetation period.
Exemplary results from the case studies in the continental region will be presented and discussed in the context of the overall concept.
A Probabilistic Forecast for Multi-year ENSO Using Bayesian Convolutional Neural Network
Authors: Puthiyadath Sreeraj , Paul Arya , Baduru Balaji , Pavanathara Francis
Published: March 2024

El Niño Southern Oscillation (ENSO) significantly influences Earth's system and regional climate patterns. Despite dedicated efforts spanning decades, the precise prediction of ENSO events through numerical modelling beyond  one-year lead time remains a formidable challenge. The advent of deep learning-based approaches marks a transformative era in climate and weather prediction. However, many machine learning-based studies attempting ENSO prediction are confined to singular estimates, lacking adequate quantification of uncertainty in learned parameters and overlooking the crucial need for a nuanced understanding of ENSO prediction confidence.
Here, we introduce a deep learning-based Bayesian Convolutional Neural Network (BCNN) model that provides probabilistic predictions for ENSO  with a lead time of up to 24 months. The Bayesian layers within the CNN maintain the capability to predict a distribution of learned parameters. The inherent capacity for uncertainty modeling enhances the reliability of BNNs, making them particularly valuable in operational services. The model was initially trained using globally gridded monthly sea surface temperature and upper 300 m integrated ocean potential temperature predictors from 25 Climate Model Intercomparison Project (CMIP) models, including 11 CMIP5 and 14 CMIP6. To address systematic errors in the BCNN, reflecting those of the CMIP samples, a learning transfer technique was applied using Simple Ocean Data Assimilation (SODA) reanalysis predictors spanning from 1871 to 1980. Validation of the all-season correlation skill of the Nino3.4 index in the BCNN model demonstrates significantly higher accuracy compared to current state-of-the-art dynamical forecast systems. This research holds substantial socio-economic implications as it enhances our forecasting capabilities and rigorously quantifies forecast uncertainties, providing valuable insights for planning and policy-making.
Precise dating of the 8.2 kyr event provides evidence for global climate response
Authors: Adolphi Florian , Sigl Michael , Beer Jürg
Published: March 2024

The 8.2 kyr event was the most pronounced Holocene cooling seen in Greenland ice cores and is one of the Global boundary Stratigraphic Points (GSSPs) subdividing the Holocene epoch. It is believed to be caused by the sudden drainage of North American proglacial lakes affecting the Atlantic Meridional Overturning circulation. The event had a profound impact on North Atlantic Climate and the global monsoon system while its impact beyond the Northern Hemisphere is less clear.
Here, we provide a precise synchronization between Greenland and Antarctic ice cores around the 8.2 event via volcanic tie-points. Using the global production rate variations of cosmogenic radionuclides (10Be in ice cores and 14C in tree-rings) we then anchor the event on the absolutely dated tree-ring timescale. This allows us to precisely and absolutely date this GSSP at the site where it has been formally defined (i.e., Greenland Ice Cores), circumventing the uncertainty of the Greenland Ice Core timescale, and compare its age to independent estimates from U-Th-dated speleothems. Based on these findings, we provide evidence for a global impact of the 8.2 kyr event beyond the Northern Hemisphere and discuss the its propagation around the globe and its impact on Holocene climate dynamics.
Management of rockburst risks in deep underground engineering through controlled contour blasting
Authors: Lu Ang , Yan Peng , Lu Wenbo , Li Xiaofeng , Cao Yuan
Published: March 2024

During the development of deep underground engineering projects, the surrounding rock is susceptible to significant deformation, rockburst, and other engineering disasters. The Jinping II Hydropower Station in China experienced several highly intense rockburst during the excavation of auxiliary tunnels and the drainage tunnel. To better understand the rockburst failure process and investigate possible mitigation solutions, the combined finite-discrete element method (FDEM) is adopted to model the development and evolution of the excavation damaged zone (EDZ) also associated to controlled contour blasting. To assess the mechanical effectiveness of this method, numerical simulation analyses employing the failure approaching index, energy release rate, and excess shear stress indices are conducted.  Results suggest that blasting-induced damage significantly influences the energy accumulation patterns in the surrounding rock. Changes in blasting design schemes lead to distinct evolution processes of surrounding rock damage, consequently affecting the energy release processes and the rockburst susceptibility. Recommendations for optimizing contour blasting parameters are also proposed to help reduce the risk of rockburst.