bluuebunny/crossref_metadata_2025 huggingface dataset:
Method of cable floating correction based on ghost reflection traveltime controlled by coherent analysis
Authors: Yan Zhonghui , Wang Xiaojie , Yang Jiajia
Published: March 2024

The high-resolution and small trace marine seismic exploration method has the characteristics of high dominant frequency and wide frequency band, which is an important means for the study of near-seabed stratigraphic sequence and fine structure, gas hydrate exploration and so on. The particularity of acquisition and the inherent problems of equipment cause unequal floating effect of the cable, resulting in unevenness, even bending and shaking of the in-phase axis on the gathers after NMO correction，which affects the effect of in-phase stacking and reduces the resolution and imaging accuracy of seismic data processing. The conventional residual moveout correction methods such as: interactive pick-up seabed reflection and ghost reflection traveltime fitting method, gather residual moveout correction method, etc., due to the large amount of pick-up, high quality requirements of gathers, and the residual moveout is a comprehensive reflection of the cable unequal floating, inaccurate speed and anisotropy, it is difficult to accurately identify whether residual moveout is caused by the unequal floating of the cable, which will cause errors in the correction results. This paper proposes a cable floating correction method based on ghost reflection traveltime controlled by coherent analysis. Firstly, the ghost reflection traveltime of the seabed reflection and receiver points are interactively picked up on the shot gathers in intervals, the information of all shots is obtained through fitting interpolation, and the real-time depth of the cable is obtained based on the moveout, and the initial moveout correction amount is calculated; Then the reference moveout correction amount is obtained through a two-dimensional coherent algorithm based on model trace constraints. Finally, based on the cross-correlation coefficient, a weighted selection is made to obtain an accurate residual moveout of unequal cable floating, and the moveout is applied after smoothing, the effect of in-phase stacking is achieved, thereby improving the imaging quality of seismic data. The test analysis combining synthetic data and actual processing shows that, compared with the conventional correction methods, the method proposed in this paper is more accurate and effective.
Joint inversion of gravity and seismic data along the CMD01 profile on the southwestern margin of Madagascar and analysis of crustal structure
Authors: zhang yongqi , Tang yon
Published: March 2024

The paper is based on the actual gravity, magnetic, and two-dimensional multi-channel seismic profiles obtained during the 2021 Sino-Malagasy international cooperative survey. Through the joint inversion of gravity and seismic data along the CMD01 profile, which traverses the southwest margin of Madagascar, combined with the interpretation and analysis of seismic profiles, the crustal structure, tectonic units, and evolution of the southwestern margin of Madagascar are studied. The main achievement is the establishment of a crustal density model for the southwestern margin of Madagascar, revealing thinned continental crust and the presence of magmatic underplating in certain segments. From land to sea, structural units such as thinned continental crust, continental-ocean transition zone, and oceanic crust domain can be delineated. Due to the influence of Davie Fracture Zone, the continental-ocean transition zone exhibits typical characteristics of a transform-type margin. Combining plate reconstruction and comparative analysis with the northern conjugate margin of Mozambique, the developmental evolution of the southwestern margin of Madagascar is reconstructed. This study has significant theoretical implications for deepening the understanding of the rifting and separation of the Gondwana continent, the developmental evolution of the East African passive margin, and maritime delineation.
Phasic variations of winter Beijing haze and its possible association with Arctic sea ice loss
Authors: Hua Wenli , Wu Bingyi
Published: March 2024

The continuous melting of Arctic sea ice affects the spatial distribution of the air temperature field in the Arctic–Eurasia and then modulates the winter haze days in Beijing to produce phased changes. The interdecadal variation of winter haze days in Beijing has a high consistency with the periodic fluctuation of winter air temperature in the Mongolian Plateau. The warmer Mongolia Plateau corresponds to more haze days, while the colder Mongolia Plateau corresponds to less haze days. The temperature variation in the Mongolian Plateau is affected by the Arctic–Eurasia temperature spatial pattern and also shows obvious low-frequency variation characteristics after 2004. The numerical simulation experiment of Arctic sea ice forcing can reproduce the above characteristics of temperature distribution, and the key circulation field anomaly configuration that affects the periodic change of haze days in Beijing can also be simulated. The model results show that the continuous melting of Arctic sea ice has an important contribution to the low-frequency variation of winter haze days in Beijing, and the continuous melting of Arctic sea ice causes the alternating distribution of warm Arctic—cold Eurasian and warm Arctic—warm Eurasian patterns by affecting the atmospheric circulation in mid-high latitude in winter, which is conducive to the staged change of winter haze days in Beijing.
Desertification vulnerability under accelerated dryland expansion
Authors: Sun Chuanlian
Published: March 2024

Given accelerated dryland expansion, studies on aridity-driven desertification are of great importance for advancing the understanding of land degradation mechanisms and developing possible mitigation measures. However, how increased aridity drives ecosystems toward desertification and its impacts on desertification vulnerability both in space and over time are largely unclear. Here, we collected eight key ecosystem structure/functioning data (including soil, vegetation and animal) for threshold identification using piecewise linear models, and then linked them to biome shifts to explore the process of AI-driven desertification. The results show that ecosystems along aridity index (AI) gradients experience three vulnerable stages featuring different threshold and biome responses: a low vulnerability stage (AI: 0.5-0.65; mainly featuring a soil fertility loss and a forest decline), a moderate vulnerability stage (AI: 0.65-0.75; mainly featuring accelerated vegetation degradation) and a high vulnerability stage (AI: 0.75-1; mainly featuring rapid overall land degradation). According to further simulations, areas with low to high vulnerability account for 31% of the global terrestrial area, which is projected to increase by 18.8% (21.2%) under the greenhouse gas emission scenario SSP2-4.5 (SSP3-7.0) by the end of the 21st century. Given increased vulnerability and population growth, Africa and East Asia are exposed to great desertification risk and ensuing contradiction between humans and lands. These findings can provide a theoretical and practical reference for ecosystem management and policy development, which are critical for global ecological security and human welfare in areas threatened by desertification.
The three-dimensional co-seismic and co-tsunami ionospheric perturbations related to the 2011 M9.0 Tohoku earthquake in Japan
Authors: Song Rui , Hattori Katsumi , Shen Xuhui , Liu Jann-Yenq
Published: March 2024

The three-dimensional (3-D) ionospheric electron density disturbances (dNe) concerning the 2011 M9.0 Tohoku-Oki earthquake were reconstructed using the total electron content data monitored by the ground-based Global Navigation Satellite System receivers and an improved constraint least-square fitting algorithm based on the computerized ionospheric tomography technique. First, we studied the overall 3-D dNe structures caused by different waves, such as Rayleigh waves (RWs), acoustic waves (AWsepi) and gravity waves (GWsepi) generated by the epicenter rupture and the internal gravity waves (IGWstsu) launched by the following tsunami. Then, we investigated these wave propagation characteristics in the ionosphere in the height interval of 190 - 490 km. RWs mainly existed below the F2 peak height, with propagating speeds ranging from 1.3 km/s to 3.3 km/s. The propagation speeds of AWsepi showed significant height dependence, that was about 0.65 km/s in 190 km and 0.90 km/s above the F2 peak height. GWsepi propagated at speed about 0.45 km/s became obvious 30 min after the earthquake. IGWstsu with a horizontal phase velocity of about 0.27 km/s was distinguished in the height interval of 190 - 490 km successively 42 min after the main shock. Finally, we studied the vertical dNe phase evolution in the F2 layer. While dNe induced by the AWsepi coupled with RWs was featured by steep-slope ascending phase variation structure, the GWsepi-induced perturbation was featured by steep-slope descending phase or near-vertical structure. The vertical dNe phase caused by IGWstsu presented remarkable curving descending structure.
Loss of energetic electrons in the vicinity of Io
Authors: Long Minyi , Ni Binbin , Cao Xing , Lu Peng , Guo Deyu , Wang Shaobei
Published: March 2024

Io plays a dual role in the Jovian magnetosphere, that is, its active volcanism provides a main plasma source of the magnetosphere, and it loses energetic particles within radiation belts as well which has been observed by spacecraft (Galileo and Juno). On 12 February 2019, the Juno spacecraft crossed the particle drift shells (L shells) of the moon Io and found a wide and a narrow decrease in the energetic electrons which are thought to be dominantly caused by wave-particle interactions. Via including moon absorption and wave-scattering induced by hiss waves, we simulate the evolution of electron fluxes by the radial diffusion equation. Our results show that the moon absorption dominates the loss of energetic electrons, and hiss waves play a secondary role in decreasing the fluxes of energetic electrons in the vicinity of Io but can widen the radial distance of the decrease of electron fluxes. Furthermore, simulation results indicate that the pitch angle distributions of energetic electrons will transfer to 90°-peak distributions due to moon absorption and hiss scattering. Our study helps to deepen the comprehensive understanding of the dynamic evolution of energetic electrons in the vicinity of Io.
Spatio-temporal evolution of cropland ecosystem services value and its spatially varying dominate over the past two decades: A case study in Jiangxi Province in Southern China
Authors: Xie Modian , Hu Bifeng , Wen Yali , Yang Jiangtao , Wu Chongcan , Teng Hongfen , Zhou Yin , Li Hongyi , Shi Zhou
Published: March 2024

Revealing the spatio-temporal heterogeneity of cropland ecosystem services and identifying its main driving factors is a prerequisite for managing cropland and ensuring sustainable agriculture. The cropland ecosystem services are impacted by both cultivation practices and the natural environment, which lead to high heterogeneity. Therefore, making clear the cropland ecosystem service value (CESV) dynamic and its driving factors are still a great challenge in agricultural production areas. Jiangxi Province is located in eastern China and it is one of the main grain production regions in China but face great pressure of cropland degradation due to rapid industrialization and urbanization in the past two decades. However, the knowledge on the spatio-temporal variation of CESV and related dominators is largely retain unclear in Jiangxi Province. To fill this gap, we integrated different biophysical models and value estimation methods to map the CESV in Jiangxi Province. The CESV from 2001 to 2020 was mapped with a spatial resolution of 1 km, and the temporal trend was explored using Theil-Sen and Mann-Kendall test method. Subsequently, the influencing pathways of both natural and anthropogenic driving factors on CESV were contrasted utilizing partial least squares structural equation modeling. The spatial correlation and heterogeneity between CESV and its driving factors was also revealed by the bivariate Moran’s I method. Finally, the geographically weighted regression was adopted to identify spatially-varying primary driving factors which dominate the variation of CESV across the study area. Our results revealed that: (1) the CESV in Jiangxi province increased from 257.84 billion yuan to 312.37 billion yuan from 2001 to 2020; (2) the CESV in most of the study area (97.47%) was featured by an increasing trend; (3) vegetation and terrain factors have the highest contribution to the variation of CESV, followed by soil properties; (4) the CESV was positively correlated with saturated soil hydraulic conductivity, clay, elevation, slope, leaf area index, vegetation cover fraction in the study area, while significantly negatively correlated with population density and nighttime light index; (5) the proportion of areas where CESV was dominated by vegetation cover fraction was the largest, followed by saturated soil hydraulic conductivity, elevation, and slope. Based on our findings, we put forward several suggestions to underpin sustainable cropland ecosystem management and development. Our research offers an insightful understanding of spatio-temporal heterogeneity of CESV and can provide important implications and useful guidance for enhancing the ecosystem functions of cropland.
Seismic Imaging of Koyna-Warna region using high frequency ambient noise tomography
Authors: Pasagadgu Sion Kumari , Gupta Sandeep , Kumar Sanjay
Published: March 2024

The Koyna Warna Seismic zone (KWSZ) in the western India is a classic example of Reservoir Triggered Seismicity (RTS). The earthquakes in KWSZ are primarily related with reservoir. Since this region is totally covered by the Deccan basalt, therefore, few studies suggest role of variation in the basalt thickness for the seismicity in the KWSZ. Further, due to poor transmission of seismic energy trough trap, sub-basalt information is difficult. In the present study, we investigate basalt thickness variation in the KWSZ, to be used for further study of seismotectonics and geodynamics of the KWSZ. We conduct high frequency ambient noise tomography using dense network of ~100 short period seismic stations.  The 3-D shear velocity model (~10 km) beneath the KWSZ reveals distinct variation in the basalt thickness and sub-basalt crustal shear velocity structure.
Key words: Koyna-Warna Seismic Zone, Basaltic thickness, Ambient Noise tomography, Seismotectonics.
The rapid life of Arctic sea-ice ridge consolidation and melt
Authors: Salganik Evgenii , Lange Benjamin , Katlein Christian , Matero Ilkka , Divine Dmitry , Itkin Polona , Høyland Knut , Granskog Mats
Published: March 2024

In this study, we cover observations of the rapid consolidation and enhanced melt of Arctic sea-ice ridges. During the freezing period, the consolidated part of sea ice ridges is usually up to 1.6–1.8 times thicker than surrounding level ice. Meanwhile, during the melt season, ridges are often observed to be fully consolidated, but this process is not fully understood. We present the evolution of the morphology and temperature of a first-year ice ridge studied during MOSAiC from its formation to advanced melt. From October to May, the draft of first-year ice at the MOSAiC coring site increased from 0.3 m to 1.5 m, while from January to July, the consolidated layer thickness in the ridge reached 3.9 m. We observed several types of ridge consolidation. From the beginning of January until mid-April, the ridge consolidated slowly through heat loss to the atmosphere, with a total consolidated layer growth of 0.7 m. From mid-April to mid-June, there was a rapid increase in ridge consolidation rates, despite conductive heat fluxes not increasing. In this period, the mean thickness of the consolidated layer increased by 2.2 m. We also estimated a substantial snow mass fraction (6%–11%) of ridges using analysis of oxygen isotope composition. Our observations suggest that this sudden change was related to the transport of snow-slush inside the ridge keel via adjacent open leads that decreased ridge macroporosity, which could result in more rapid consolidation.During the summer season, sea ice melts from the surface and bottom. The melt rates substantially vary for sea ice ridges and undeformed first- and second-year ice. Ridges generally melt faster than undeformed ice, while the melt of ridge keels is often accompanied by further summer growth of their consolidated layer, which increases their survivability. We examined the spatial variability of ice melt for different types of ice from in situ drilling, coring, and multibeam sonar scans of the remotely operated underwater vehicle. Six sonar scans performed from 24 June to 21 July were analyzed and validated using seven ice drilling transects. The area investigated by the sonar (0.4 km by 0.2 km) consisted of several ice ridges, surrounded by first- and second-year ice. We show a substantial difference in melt rates for sea ice with a different draft. We also show how ridge keels decay depending on the keel draft, width, steepness, and location relative to the surrounding ridge keel edges. We also use temperature buoy data to distinguish snow, ice surface, and bottom melt rates for both ridges and level ice. These results are important for quantifying ocean heat fluxes for different types of ice during the advanced melt and for estimating the ridge contribution to the total ice mass and summer meltwater balances of the Arctic Ocean.
Advanced Front-End Development for Customer-Facing Services in a Hybrid Cloud and High-Performance Computing Cluster for Earth Observation Data Processing
Authors: Sophocleous Marios , Kemgang Stephane , Nicolaides Christos , Karageorgiou Sozos
Published: March 2024

This presentation elucidates the intricate details of the front-end development within an Earth Observation for European Union (EO4EU) platform. Our paramount emphasis is directed towards crafting customer-facing services embedded within a hybrid Cloud and HPC cluster, encompassing a sophisticated repertoire of front-end channels, namely the Command Line Interface (CLI), Visual/Textual Workflow Editor, Dashboards, and an OpenEO Application Programming Interface (API) providing the versatility for any user to connect to these customer-facing services of the EO4EU platform whilst using their very own and customised dashboard.A cornerstone of our work is the seamless integration of a versatile cloud security and authentication mechanism (User Management Module (UMM)), meticulously designed to establish a robust framework for secure and authenticated access to EO4EU services and data offerings. This framework is strategically interwoven with the creation of pivotal artifacts—maps and graphs—via the aforementioned front-end channels, strategically addressing the imperative of catalyzing widespread platform use and fostering data adoption.In response to exigent high-end visualization requirements, we orchestrate the engagement of computing elements on the EO4EU core infrastructure, a strategic alignment with the session's core theme on the convergence of Cloud and HPC for Earth Observation data processing. Our technical approach extends beyond conventional paradigms, incorporating support for Extended Reality (XR) interfaces, including the prospective implementation of an automated mechanism for generating Virtual Reality (VR) interfaces seamlessly intertwined with EO data.Furthermore, our presentation articulates the intricacies involved in the seamless integration of retrieved data and visualization constructs into Augmented Reality (AR) applications, a demonstration of contextual relevance through parameters such as location. By delineating these technological advancements, our contribution catalyzes the ongoing discourse within the specialized session, delivering nuanced insights into the intricacies of customer-facing services within a hybrid Cloud and HPC cluster tailored for Earth Observation data processing platforms. This work not only serves as a stimulus for discussions on the broader adoption of cloud computing but also underscores the transformative potential of high-performance computing on customer-centric services in the realm of Earth Observation.
Tectonic response of the subduction channel in central Himalya revealed by magnetotelluric data north of Mount Everest
Authors: Wang Gang , Fang Hui , Zhang Yaoyang
Published: March 2024

Imaging the structure and state of the subduction channel in the Himalayan Orogenic Belt is important for understanding the deformation of the continental collision front. The high-resolution three-dimensional electrical model revealed that the electrical properties of the subduction channel north of Mount Everest are not continuous. Rather than pipeline flow, crustal thickening, and thermal transport from the subduction front, the conductors above the Main Himalaya Thrust interface are likely caused by local dehydration of the subducting material or bending of the Indian crust. North of Mount Everest, the long-distance migration and high differentiation of fluids along the Southern Tibetan Detachment System (STDS) may be attributed to the high temperature and volatiles from the U-shaped chamber underneath the STDS, as well as the pore-fluid pressure from the stress concentration of the fluidized subduction channel.
Shallow Water Bathymetry Recovery of South Penghu Marine National Park, Taiwan
Authors: Huang Chun-Chuan , Tseng Kuo-Hsin
Published: March 2024

Abstract:
The South Penghu Marine National Park is one of a few pristine environments with low pollution and minimal development in the surrounding ocean of Taiwan. However, the coasts in this region are susceptible to changes in appearance due to natural forces such as wind, waves, and currents. The traditional way of mapping and monitoring intertidal zones and nearshore shallow water topography have been high-cost tasks. Hence, this study aims to use space-born LiDAR on ICESat-2 launched by NASA for depth measurements, coupled with the optical satellite to map the coastal and seafloor topography of the South Penghu Marine National Park more promptly and accurately.
To map the shallow water bathymetry in this area, we first filter and extract elevation profiles from ICESat-2 ATL03 photon data, which can detect depths reaching up to 40 meters in clear waters. Next, we adopt the green and blue bands from Sentinel-2 images and apply the modified log-ratio model for water depth estimation. In our preliminary tests, the ICESat-2 seafloor elevation achieves an accuracy of ~50 cm as compared with airborne LiDAR data. Also, the accuracy of water depth derived from Sentinel-2 is about 10% of the depth. It is summarized that an integration of ICESat-2 and Sentinel-2 can provide more timely observation of changes compared to traditional methods. It also overcomes the challenges in the areas inaccessible by vessels due to coral reef terrain and unsafe under keel clearance.
Key Words: Satellite Derived Bathymetry, Log-Ratio Model, Taiwan South Penghu Marine National Park
Pleistocene vegetation dynamics of the Olorgesailie-Koora Basin in the last 1 Myr: Implications for human evolution and technological innovations 
Authors: Kinyanjui Rahab , Potts Richard , Behrensmeyer Anna , Dommain René , Riedl Simon , Lupien Rachel , Clark Jennifer , Uno Kevin , Deino Alan
Published: March 2024

The Olorgesailie basin, southern Kenya Rift, is a renowned prehistoric site that preserves evidence of hominin behavior over the past ~1 million years. During this period the basin experienced environmental variability in response to orbitally controlled climate changes and tectonic forcing, which together influenced preservation of evidence for early human behavior and technological innovations. Palaeobotanical data from phytoliths extracted from outcrop paleosols show that vegetation cover varied subtly across the landscape and through time, shifting between wooded grasslands and open grasslands. Low-resolution outcrop data and a sedimentary hiatus between ~500 ka and ~320 ka hinder understanding of when important vegetation changes may have occurred and how these influenced mammalian species turnover or major transitions in hominin technology and behavior.
        Here we report vegetation data analyzed from a well-dated and continuous 139 m sedimentary core spanning the last ~1 million years, drilled from the southern area of the Olorgesailie catchment known as the Koora basin. Phytolith data from 270 samples show that climate largely controlled vegetation variability in the basin. These changes appear to have influenced mammalian assemblages and corresponded with changes in human behavior and technological transitions in the southern Kenya rift. Our record shows a significant shift towards more C4-short-Chloridoideae grasslands associated with increased variability in available fresh water, corresponding to the technological transition from Acheulean to Middle Stone Age around 320 ka. In addition, phytolith indices indicate increased vegetation variability 330-220 ka, corresponding to high variability in terrestrial and freshwater conditions resulting from tectonic, hydrological and ecological changes. The sediment core thus provides a unique, high-resolution opportunity to evaluate vegetation dynamics of the Olorgesailie-Koora region, providing new insights on how vegetation may have influenced our ancestors’ behavioral changes over the past ~1 million years.
Effects of biochar derived from wheat straw and chicken manure on the immobilization of Cu, Zn and Cd in sludge composting
Authors: Quan Weici , Yang Kai , Gong Yiwei , Yang Kaiming , Ai Yadi , Cheng Hongguang
Published: March 2024

The increasing production of sludge has added to the sewage treatment burden, making its disposal an important challenge for urban environmental management. Biochar has great potential to effectively reduce the mobility and bioavailability of heavy metals in municipal sludge due to its adsorption capacity. This study conducted a 20-day sewage sludge composting experiment with the addition of wheat straw and chicken manure biochars to test their effects on the sewage sludge physicochemical properties and immobilization of copper (Cu), zinc (Zn), and cadmium (Cd) in the sewage sludge. During composting, the physicochemical properties of the treatments changed to different degrees compared to the original pile. Specifically, pH, CEC, TP, and TK increased, while the content of OM and TN decreased. As a result of the concentration effect, the total contents of Cd, Cu, and Zn increased in both of the C1 and C2 treatments. In the present study, heavy metals were stabilized more effectively by the wheat straw biochar than that derived from the chicken manure. Both types of biochar are effective at immobilizing Cd, Cu, and Zn in the compost, while WSB is more effective. These results are affected by indirect physicochemical properties of the compost, as well as the direct ion exchange, complexation and precipitation. Therefore, these results indicate that it is feasible to use biochar, especially derived from the wheat straw, to immobilize heavy metals in the sludge.
Chemical differences in the non-protected carbon pool of four Hungarian soils with different vegetation types
Authors: Filep Tibor , Zacháry Dóra , Tőke Orsolya , Domján Attila , Szalai Zoltán
Published: March 2024

Soil organic matter is not a homogeneous material, but can be broken down into pools with different mean residence times (MRT) ranging from days to thousands of years. Differences in the degradability of carbon pools can be explained by the different stabilization mechanisms of the carbon. Particulate organic matter (POM) is considered as a non-protected carbon pool of  organic matter, which could respond rapidly to environmental changes. To provide an insight into the changes in chemical structures of POM and the patterns of decomposition, soils from area of different types of vegetation (grass, spruce, oak and arable) were examined in a 1-year laboratory incubation at three different temperatures (15, 25 and 35 °C). The POM samples was analysed using CPMAS 13C NMR spectroscopy and it was hoped to reveal the effects of different plant cover on the chemical patterns in POM fractions.
The chemical composition of the POM fraction of the soils with different vegetation differed significantly according to the results of NMR analysis. The grassland POM contains a high amount of O-alkyl compounds and relatively few alkyl-like compounds. In contrast, spruce soil POM contains high amounts of alkyl compounds. The amount of O-alkyl compounds decreased during incubation at 25 and 35 °C, whereas this was not observed at 15 °C. Similarly, the 25 °C and 35 °C incubation had a significant effect on the alkyl/O-alkyl and aryl/O-alkyl ratios, as these values increased compared to the starting conditions, while a small decrease was observed for the 15 °C incubation.
This work was supported by the Development and Innovation Fund of Hungary [grant No. NKFIH 132191].
Recurring flooding of the World Heritage site of Jenne since 1945 in the Republic of Mali, West Africa 
Authors: Dembele N'dji dit Jacques
Published: March 2024

The city of Jenne in Mali (West Africa) has been a UNESCO World Heritage since 1988 and is renowned because of its mud brick-made mosque from the 15 century. It is located in the central part of Mali in a geomorphological region known as the Niger Inland Delta, a very plane floodplain with a slope gradient of 2 to 5 degrees formed by the junction of the Niger River and Its tributary, the Bani River.  Because of this location, the city has been frequently flooded since 1945, when after the rainfall season in the upper Niger and Bani upper reaches, the water flows reach this very plane region forming numerous lakes and flooding the area. the spatial extension of this flooding is highly linked to the annual rainfall in the Niger and Bani River Watershed. We used field cartography done with the implication of the elders and local community members that help to map the spatial extension of the floods that they have experimented with to study the recurring flooding of the city. The field data were recorded using mobile GPS and Fieldpapers, an OpenStreetMap online mapping tool. The maps were made for the floods that occurred between 1945 and 2019 as before that period the memory of the flooding was scarce. The results show that the city of Jenne has been flooded for 19 years but with different locations and spatial extensions of the flooded areas inside the city. A map has been made for each flooded year. Later, a synthesis map was made combining all the flooded areas during the period of observation. It was found that the southern, southeastern, and northeastern parts of the city were the most flooded. Nowadays, although many flood management activities and actions have been undertaken, the city is still flooded especially the Southeastern part of the city.
Coupled model on consolidation and porewater mobilization within low-permeability sediments
Authors: Qiu Wenkai , Ma Teng , Du Yao , Van Cappellen Philippe
Published: March 2024

Groundwater, a crucial freshwater resource, constitutes over 95% of the world's discovered freshwater. It effectively mitigates the uneven spatial distribution of surface water, prompting the development of industry, agriculture, and human society. In most cases, the exploitation of groundwater resources inevitably involves the consolidation of low-permeability sediments. The mobilization of porewater from it, carrying various chemical components, had leaded to worldwide water quality degradation and endemic diseases. Consequently, close attention and control over the mobilization of porewater from low-permeability sediments during extraction is urgently needed. However, the mobilization of porewater caused by consolidation is often confused with porous medium flow. Existing models considering porewater mobilization during compaction contain incomplete assumptions about porewater flow and solute mobilization within low-permeability sediments, making it challenging to incorporate porewater mobilization from these sediments into reactive solute transport models during groundwater abstraction. Further investigation would benefit grasping water quality evolution during groundwater abstraction and for risk management of clean freshwater resources. In this study, we developed a physical device to simultaneously monitor the consolidation and porewater mobilization in low-permeability sediments. By refining Gibson's large deformation consolidation theory based on experimental observations, we describe both consolidation and porewater mobilization processes within low-permeability sediments under a unified framework. This approach aims to provide new insights and feasible solutions for integrating low-permeability sediments into the watershed-scale three-dimensional groundwater model, particularly for understanding water quality origins in Quaternary aquifers.
Enhancing sub-ice geology in East Antarctica with Self-Organizing maps based on gravity, magnetic and radar data
Authors: Ebbing Jörg , Liebsch Jonas , Matsuoka Kenichi
Published: March 2024

Sub-ice geology significantly influences the dynamics and future evolution of the Antarctic Ice Sheet, but largely inaccessible for direct sampling. Here, we present an approach, where we use a Self-Organizing Map (SOM) to describe sub-glacial properties. Based on attributes derived from gravity, magnetics and radar data from the NASA Operation Ice Bridge dataset in East Antarctica, we train a SOM, where attributes are selected to best represent sub-glacial conditions. Therefore, we study the trade-offs between these data sets helping to identify for which properties these are most sensitive.The trained SOM identifies the outlines of the main geological structures beneath the ice and supplements models based on inverse and forward modelling. In contrast to such often regional interpretations, the SOM captures small-scale structures at the ice bed, as we illustrate with case examples, and highlights areas with inconsistencies in existing geological interpretations. The SOM can furthermore be used as input for inverse modelling of the physical properties of the sub-glacial geology in Antarctica.
Lithologic prediction of strata based on hierarchical Bayesian modeling: an example of Carboniferous strata in the northern Junggar Basin
Authors: Hou Yujian , He Zhanxiang , Song Fangda , Zhai Yibo , Jiang Qiyun
Published: March 2024

In geophysical exploration, accurately predicting lithology is essential.  The uncertainty in inverse solutions and variable physical properties across different strata often require manual lithology interpretation.  To overcome this, we developed a method integrating multiple geophysical inversion results for regional lithology prediction.  This method, applied to empirical data, enables lithological classification of Carboniferous reservoirs.  It utilizes custom spatial geological priors, discernible through well-logging and core geological principles.  Our approach, grounded in a hierarchical Bayesian model, includes data fitting and regularization components.  The data fitting component uses well-log data from proximate areas for training, and the regularization component incorporates established geological knowledge.  Our approach ensures that lithological classification is consistent with fundamental geological rules and aligns with inversion results.  We employed diverse inversion data types (electromagnetic, seismic, gravity, and magnetic) from the Carboniferous reservoirs in the northern Junggar Basin.  Our lithological predictions, validated against well-log data, offer a fresh perspective on integrated geophysical interpretation and diminish subjective bias in geological assessments.
Limnogeological investigations of the Montiggler Seen (South Tyrol, Italy) reveal paleoshaking evidence caused by surface rupturing earthquake in the Southern European Alps
Authors: Niederstätter Markus , Strasser Michael , Ramisch Arne , Moernaut Jasper
Published: March 2024

Assessing the hazard of extraordinary strong earthquakes in slowly deforming intraplate regions such as the European Alps is difficult, due to a lack of information on their occurrence. They are characterized by long recurrence intervals and identifying the source faults is difficult. However, on-fault evidence of a surface rupturing earthquake in the eastern Southern Alps was indicated by an archeoseismological study of Galadini and Galli (1999) in Egna (South Tyrol, Italy), which is in an area of low recent seismic activity. Displaced walls of a Roman Age building and paleoseismic trenches revealed the rupture of a NNE-SSW striking fault, which is dated to the 3rd century CE. To test the hypothesis, this lacustrine paleoseismology study aims to find evidence of ground shaking in the sediments of Kleiner Montiggler See, a lake located only 10 km from the archeological site. Multiproxy analysis of sediment cores reveals an event layer at a depth between 64 and 69 cm below the lake floor. It is characterized by a sharp base, high density, grainsize oscillations within a normal grading trend, a high amount of detrital material and a decrease in organic matter, compared to the background sediment. After evaluating and finally excluding many possible processes that could have induced the deposit, it can be concluded that a seismic seiche caused bottom currents, resuspending sediment and eroding material from the shore that finally got deposited as an outstanding event deposit in the deeper parts of the basin. According to our 14C based age-depth model, the event layer occurred between 8 and 450 years CE (95% probability range; mean age 222 CE), therefore supporting the hypothesis of the Roman Age surface rupture at the Egna site. This is the only event of this type recorded in the lake sediments of Kleiner Montiggler See in the last ~5000 years.  A minimum macroseismic intensity (EMS-98) of VII at the lake was estimated for the ground motion caused by the Egna fault rupture. This was done by investigating the sedimentological characteristics of the event layer, as well as considering negative evidence for other large, historical earthquakes and possible long-term catchment response recorded in the sediments. By applying an intensity prediction equation, a minimum estimated magnitude (Mi) of 6.2 ± 0.5 was derived. Due to negative evidence in Lake Ledro (63 km SW of Egna) at this timing, a maximum magnitude of 6.0 ± 0.5 was estimated. Therefore, we conclude that the magnitude of this event was most likely between 5.7 and 6.5. This study indicates that extraordinary strong and thus hazardous earthquakes can occur in areas of low recent seismic activity. It therefore provides important information for improving seismic hazard assessment and the estimation of the maximum credible earthquake in South Tyrol.
Quantifying projected effects of climate change on low-flows in the Mur River, Austria: Adapting weather generator outputs to reflect downscaled EURO-CORDEX datasets
Authors: Valent Peter , Pitterle Denise
Published: March 2024

In the context of ongoing climate change, the use of climate model predictions plays a crucial role in preparing adaptation strategies that could reflect the expected changes in low-flow conditions within water systems. These predictions are often non-stationary and thus not very suitable for a comprehensive statistical analysis of extremes, mainly due to very short periods of quasi-stationary conditions. In this study, we address these problems by adapting a 10,000-year long dataset of synthetic meteorological outputs, representing the current climate conditions and produced by a large multi-site stochastic weather generator, to account for both spatial and temporal variability of the changing climate through a delta-change approach. We adapted this dataset to depict the mean climate conditions of the final three decades of the 21st century, as defined by 26 different scenarios (13 GCM-RCM combinations for 2 different RCPs) incorporated into the high-resolution Austrian National Climate dataset (ÖKS15) derived from the EURO-CORDEX data. We employed an HBV-distributed hydrological model to simulate synthetic river discharges for both the current and 26 future climate conditions in the Mur River, Austria. The subsequent analysis of the low-flows during the vegetation period was focused on the changes in low-flow frequencies and the number, duration and magnitude of dry periods. The results indicate that the adopted delta-change approach reflects the changes in rainfall amounts but does not address the changes in rainfall frequencies. Future research should, therefore, prioritize the development of methods that can accommodate qualitative changes in rainfall distribution.
Exploring the discrepancy between the seasonality of atmospheric convection and precipitation in the Colombian Amazon region 
Authors: Vanegas Izquierdo Francy Alejandra , Hernández-Deckers Daniel
Published: March 2024

Atmospheric convection is the main mechanism responsible for precipitation in tropical and equatorial regions, whose rainfall regimes are high. Thus, the number of convective events and precipitation are expected to have similar seasonalities. However, the number of convective events in the northwestern Amazon region has a bimodal seasonal distribution, whereas precipitation has a clear unimodal regime. This discrepancy may be related to seasonal variability in convective dynamics in this region; for example, aerosol concentrations, moisture sources and/or surface fluxes may vary significantly at the seasonal scale, which may in turn impact fundamental properties of the convective systems. In order to investigate this, we identify deep convective events between 2011 and 2021 with an automated algorithm that uses infrared geostationary satellite data, and obtain  daily precipitation from available in-situ measurements. Other precipitation products with better coverage, such as IMERG, are not suitable due to their poor representation in this region on short timescales (daily or sub daily). The largest discrepancy between the seasonality of the number of convective events and monthly precipitation takes place during May-August, when the number of convective events decreases, but precipitation reaches its peak monthly values. We find that during those months, mean precipitation per convective event is highest, as well as the average horizontal extent of the events. This suggests that the nature of convective events varies significantly throughout the year, which may give rise to this discrepancy in seasonality. Possible causes for this may be related to: a) aerosol concentrations, which have a strong seasonality related to biomass burning and could potentially impact microphysical processes, b) varying sources of moisture due to the seasonal migration of the ITCZ, and c) seasonal changes in surface fluxes. Here we present a detailed analysis of the seasonality of various properties of the convective events in this region and explore these hypotheses in order to better understand the dynamics of convection in the Amazon region of Northwestern South America. This investigation highlights the complexity in the dynamics of deep convection at low latitudes beyond a simple correspondence with rainfall.
 
Keywords: tropical convection, Colombia, Amazon, precipitation, rainfall regime
Emplacement of the Paleoproterozoic Itareru Tonalite (NE São Francisco Craton, Brazil) during arc-continent collision revealed by magnetic fabrics.
Authors: Lazcano Patroni Oscar Andres , Bartolomeu Raposo Maria Irene , Souza D'Agrella-Filho Manoel , Paiva de Oliveira Elson
Published: March 2024

The Itareru tonalite stands as a remarkable Paleoproterozoic plutonic rock formation that intruded the Serrinha block, an ancient crustal fragment of the São Francisco Craton situated in Bahia, Brazil. This elongated, leaf-shaped body, stretching approximately 80 kilometers in a NW-SE direction, is predominantly composed of tonalite-diorite to granodiorite rocks, interspersed with numerous dioritic enclaves. Intriguingly, magnetic studies conducted on 26 sites within the Itareru pluton, including the surrounding country rocks, have revealed captivating insights into its magnetic fabric and the underlying geological processes that shaped its formation. Anisotropy of low-field magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM) measurements performed on rock samples from the Itareru pluton exhibit a remarkable degree of co-axiality. This observation suggests that all magnetic minerals within the rocks share a common orientation, which is partially attributed to the influence of regional strain. Further analysis of rockmagnetism data indicates that paramagnetic matrix minerals play a significant role in contributing to the overall magnetic susceptibility and AMS characteristics. However, for AARM, magnetite grains ranging from 2 to 5 micrometers in size are recognized as the primary contributors. In the central region of the pluton, magnetic fabrics exhibit signatures that are likely primary in origin, implying that these fabrics were acquired during the rocks' crystallization phase. This suggests that the magnetic fabrics reflect the flow of magma within the pluton, potentially linked to a magma feeder zone or magma chamber. The moderately inclined lineation observed in the northern part of the pluton suggests that this region was situated close to the feeder zone. In contrast, the horizontal to sub-horizontal lineations in the southern region indicate that this part of the pluton was farther away from the feeder zone. The emplacement of the Itareru tonalite was not only influenced by magmatic processes but also by regional strains associated with the collision of the Paleoproterozoic Rio Itapicuru greenstone belt with the Archean basement. This interplay between magmatic and tectonic forces resulted in the distinctive features of the Itareru tonalite, making it a prominent geological formation within the São Francisco Craton.