bluuebunny/crossref_metadata_2025 huggingface dataset:
Flood mapping in small-size water rivers: Analysis of spectral indexes using super-resolved Sentinel-2 images
Authors: Lombana Lorena
Published: February 2023

Floods are one of the most common and catastrophic natural events worldwide, making studies on the magnitude, severity and frequency of past events essential for risk management. On this wise, remote sensing techniques have been widely used in flooding diagnoses, where Sentinel-2 images are one of the main resources employed in surface water mapping. These studies have developed single band, spectral indexes and machine learning-based methods, which have typically been applied to large water bodies. However, one of the issues in identifying water surfaces remains their size. When water surfaces have sizes close to the spatial resolution of satellite images, they are difficult to detect and map. To improve remotely sensed images' spatial resolution, an algorithm for super-resolving imagery has been developed, giving good results, especially in areas covered by agricultural land with large uniform surfaces. Although this method has proved effective on Sentinel-2 images, it has not been tested for enhancing flood mapping. Thus, flood mapping is still considered an open research topic, as no suitable method has been found for all datasets and all conditions. Consequently, the present study has developed a methodology for flood delineation in small-sized water bodies. The method leverages the advantages of Sentinel-2 MSI data, image preprocessing techniques, thresholding algorithms, spectral indexes and an unsupervised classification method. Thus, this framework includes a) the generation of super-resolved Sentinel-2 images, b) the application of seven spectral indexes to highlight flood surfaces and evaluation of their effectiveness, c) the application of fifteen methods for flood extent mapping, including fourteen thresholding algorithms and one unsupervised classification method and, d) the evaluation and comparison of the performance of flood mapping methods. The technique was applied in the Carrión River, located in the Duero basin, province of Palencia, Spain. This river is classified as a narrow water body, which presents recurrent flood events due to its morphometric characteristics, fluvial dynamics, and land uses. The results obtained show optimal performances when highlighting flood zones by combining AWE spectral indices with methods such as those of Huang and Wang, Li and Tam, Otsu, and momentum-preserving thresholding algorithms and EM cluster classification.
Enhanced-gravity Analog Modelling of the Influence of Pre-existing Brittle Fabrics on Continental Rifting
Authors: Zou Yaoyao , Corti Giacomo , Maestrelli Daniele , Del Ventisette Chiara , Wang Liang , Shen Chuanbo
Published: February 2023

Along with other parameters (e.g., plate kinematics), the presence of pre-existing structures at all lithospheric scales has been proven to be of primary importance in controlling the evolution and characteristics of continental rifts. Indeed, observations from many natural examples show that even in conditions of orthogonal rifting (when extension should result in simple fault patterns dominated by normal faults orthogonal to the extension vector) the presence of inherited fabrics may result in complex arrangements of differently-oriented extension-related structures.Here, we explored the influence of pre-existing fabrics on the evolution and pattern of rift-related structures by conducting a series of analogue models deformed in an enhanced gravity field produced by a centrifuge apparatus. The crustal models reproduced a brittle-ductile system and considered the presence of pre-existing discrete fabrics in the upper, brittle crust under conditions of orthogonal narrow rifting. These fabrics were reproduced by cutting the brittle layer at different orientations with respect to the extension direction.Modelling results show that pre-existing fabrics have a significant influence on the rift-related fault pattern. These fabrics cause curvature of extension-related faults, resulting in S-shaped faults and -in some cases- en-echelon arrangement of oblique fault segments. In addition, the presence of these heterogeneities influences the rift floor subsidence by inducing significant segmentation and development of isolated depocenters. These effects are more visible during initial rifting and less pronounced for more advanced rifting stages. Similarly, increased syn-rift sedimentation tends to decrease the impact of pre-existing structures. Model results show many significant similarities with the fault pattern in many rift basins worldwide, and these findings have important insights into the development of continental rift systems in nature. 
Pattern changes in tidal channel morphodynamics under human interventions: a case of Shiziyang tidal channel in the Pearl River Delta, China
Authors: Zhang Ping , Yang Qingshu , Cai Huayang , Hoitink A. J. F.  Ton
Published: February 2023

The morphodynamics of tidal channels can be considerably altered by intensive human activities, such as the land reclamation and channel dredging. Morphological alterations of Lingdingyang Bay (LDB) in the Pearl River Delta (RPD) have received great attention, while the changes in Shiziyang (SZY) tidal channel connecting LDB with Humen Outlet is less known. In this study, bathymetric maps of the Shiziyang tidal channel in the PRD at different periods were collected to investigate the geomorphologic pattern by means of a digital elevation model (DEM). It was shown that the water depth increased with the decreasing width convergence length, indicating intensified channel deepening and narrowing, while tidal channel bed was drastically cut down due to port construction and channel dredging in 1959, 1975 and 2004, respectively. Consequently, the SZY eroded at a rate of 0.164 m/yr during the study period, with a new pattern of eastward-erosion and westward-deposition. In addition, erosion in the downstream reach (0.271 m/yr) was significantly faster than that in the upstream reach (0.006 m/yr). The EOF results showed that the impact of natural factor, channel dredging and land reclamation on bathymetric changes accounted for 48.48%, 20.54% and 11.57%, respectively. Furthermore, the spring-neap variability of tidal wave celerity and tidal amplification in SZY both increased after human interventions and there is a clear transition pattern and stronger tidal hydrodynamics according to the results of 1D analytical hydrodynamics model. Based on the model results, the decadal evolution of SZY morphology can be well reproduced by the observing water levels. The results obtained from this study can be particularly helpful for quantifying the potential impacts due to human interventions, which is useful for setting future conservation planning strategies in estuarine zones.
How will Solar Radiation Modification affect Cropland Suitability in West Africa?
Authors: Egbebiyi Temitope Samuel , Lennard Christopher , Pinto Izidine , Odoulami Romaric , Wiolski Piotr , Tilmes Simone , EGBEBIYI TEMITOPE SAMUEL
Published: February 2023

Cropland suitability, a process of evaluating the capability of a piece of land in relation to the growing conditions of a given crop, is highly essential for agricultural planning. Projected changes in the future climate are expected to significantly affect the agricultural sector, notably agricultural production which include cropland suitability. Although, previous studies have shown Solar Radiation Modification (SRM), which involves the injection of sulfur into the stratosphere to reduce insolation of the sun and cool the planet, could mitigate the impact of climate change (hereafter GHG) on agricultural production, however there is still a lack of understanding on how Stratospheric Aerosol Injection (SAI) intervention (an SRM technique) will affect cropland suitability in West Africa. The present study examines the impact of GHG and SAI on Legumes (Cowpea, Soyabean and Groundnut) and Root and Tuber (Cassava, Potato and Yam) suitability and planting season over West Africa. The Stratospheric Aerosol Geoengineering Large Ensembles (GLENS) simulation for the historical, GHG and SAI experiments for the period 1980-2009 and 2060-2089. Ecocrop, a crop suitability model was used to investigate the impact of GHG and SAI on the over West Africa owing to their economic importance to the region. Our findings shows while SAI offset the impact of GHG on temperature it leads to a reduction in rainfall over West Africa. Crop suitability decreases northwards over the region. SAI intervention will lead to an increase (over 12%) in highly suitable area for Cassava and Potato compared to GHG but leads to 3% decrease compared to historical period. In contrast, SAI results in decrease (6%) in suitable area for Legumes when compared to GHG impact over West Africa. In addition, SAI intervention will lead to a 1-2month early planting season for all legumes crops and Yam over West Africa but delay of about 2months for Cassava and Potato. The study will assist to improve our understanding on SAI intervention at mitigating GHG impact on Legumes and Root & Tuber crop production over West Africa. It will also help inform policy maker in their decision making of adaptation strategies to ensure food security and zero hunger and healthy nutrition in West Africa.
Mapping linear surface features on Europa using a deep learning framework
Authors: Haslebacher Caroline , Thomas Nicolas
Published: February 2023

The surface of Jupiter's icy moon Europa shows curvilinear geological features, so called lineaments. Some of them span over a hemisphere, while others appear only on a regional scale. These curvilinear surface features that potentially stem from cracks in the ice shell are of keen interest because they might provide a direct or indirect connection to Europa's subsurface ocean, allowing a remote sensing study of the subsurface ocean.The solid-state imager onboard the Galileo mission observed Europa between 1996 and 2002 during 11 flybys and sent back data of almost 2 gigabyte. Based on a global map mosaicked from Galileo and Voyager images at a scale of 1:15M, Leonard et al. (2019) created a global map of the surface of Europa. Their mapping shows that ridged plains make up a major part of the surface area. Ridged plains are seemingly smooth but contain a high amount of undifferentiated lineae visible at higher resolution. We attempt to create a global map of lineaments at a higher resolution than the global geologic map. Although for the Galileo dataset, this mapping could be done manually, we need to prepare for a bigger data return by NASA's Europa Clipper mission. For this purpose, we introduce a deep learning framework that can map linear surface features in Galileo images on Europa autonomously and apply it on a global scale. More specifically, we train a Mask R-CNN that can detect, classify and segment lineaments. The current status of the work is presented.References:[1] Leonard, E. J., Senske, D. A., Patthoff, D. A., Global and Regional scale Geologic Mapping of Europa, EPSC-DPS2019-57-1, Vol. 13, 2019
Effectiveness and usability of subsurface geodata visualization for training and storytelling using Virtual Reality: Immersing into a dataset from the EX-carbonate field in Central Luconia Province (Malaysia)
Authors: Jimenez Soto Grisel , Schulze Katja , Latiff Abdul Halim
Published: February 2023

Geoscience data usually is complex and comes at different scales. Effective visualization tools are crucial for efficiently examining properties and correlations when working with the datasets and for telling geoscience stories around them. Virtual Reality (VR) leads users to an immersive experience and allows for true spatial awareness and depth perception. We find that VR enhances knowledge transfer and adds a gamification moment.In the energy industry and Academia, large amounts of multiscale geo data are compiled but often remain segregated and underutilized. Core data, for example, is sitting in remote core centers and is not readily available to be integrated for improving the quality of 3D geological models and interpretations.Likewise, numerous supplemental information and geological images are required to improve the quality of any geoscience simulations. Traditionally, most visualization is tied to display on 2D computer screens. Users (geologists, teachers, and students) rely on advanced real-time visualization and interaction methods customized to geospatial data at different scales. It is the user’s objective to improve their observations and interpretations at different dimensions (2D and 3D). In this work, we study the effectiveness and usability of Virtual Reality tools for training and collaborative decision purposes. The multiscale data includes sets of cores, logs, sedimentological descriptions, and seismic. All data is presented in a unique virtual data room and immersive presentation.  The geological model and data of different scales are visualized simultaneously and interpreted jointly.Finally, we highlight the advantages of VR for training students in geoscience and geo data-data interpretation.  This is not limited to but especially true for physical data sets (e.g., core) or models from remote locations (e.g., outcrop) that are difficult to visit. Specific VR tools allow students to navigate in an immersive way through virtual geological multiscale datasets. The interactive environment makes the process of learning fun, removes distractions, and immerses the students in the subject matter at hand. Together with dedicated VR storytelling tools and supplemental documentation, this results in a quicker and deeper understanding of complex geological settings.
The Consequences of Fractional Crystallization for Basal Magma Ocean on the Long-term Planetary Evolution
Authors: Ismail Mohamed , Ballmer Maxim
Published: February 2023

     Constraining thermo-chemical evolution for the interior of terrestrial planets is substantial to understanding their evolutionary path. Thermo-chemical processes is controlled by stages of large-scale melting, or magma oceans (MO), due to the energy released during accretion, differentiation, radioactive decay of heat-producing elements and crystallization of the melt. Previous work shows that one of the product of considering fractional crystallization (FC) for  MO is a FeO-enriched molten layer or basal magma ocean (BMO) which is stabilized at the core-mantle boundary for a few billion years. The BMO is expected to freeze by FC because it cools very slowly. FC always yield a highly iron-enriched BMO and last stage cumulates. Other crystallization mode could be dominated and has not yet been systemically explored – at least for the Earth-like planets.To explore the fate of the BMO cumulates in the convecting mantle, we explore 2D geodynamic models with a moving-boundary approach. Flow in the mantle is explicitly solved, but the thermal evolution and related crystallization of the BMO are parameterized. The composition of the crystallizing cumulates is self-consistently calculated  in the FeO-MgO-SiO2 ternary system according to Boukaré et al. (2015). In some cases, we also consider the effects of Al2O3 on the cumulate density profile. We then investigate the  entrainment and mixing of BMO cumulates by solid-state mantle convection over billions of years as a function of BMO initial composition and volume, BMO crystallization timescales, distribution of internal heat sources, and mantle rheological parameters (Ra# and activation energy), . We varied the initial composition of BMO by manipulating the molar fraction of FeO, MgO, and SiO2  -based on published experiments- to model different BMO-compositions: Pyrolitic composition, After 50% crystallization of Pyrolitic composition Boukaré et al. (2015), After 50% crystallization of Pyrolitic composition Caracas et al. (2019), and Archean Basalt.For all our model cases, we find that most of the cumulates (first ~90% by mass) are efficiently entrained and mixed through the mantle. However, the final ~9% of the cumulates are too dense to be entrained by solid-state mantle convection, and rather remain at the base of the mantle as a strongly FeO-enriched solid layer. We conclude that this inevitable outcome of BMO FC – at least for Earth - leads to inconsistent evolutionary path comparing to recent geophysical constraints. FC substantially change the compositional, thermal, and geometrical properties for the lower mantle structures.  An alternative mode of crystallization may be driven by an efficient reaction between a highly-enriched last-stage BMO with the overlying mantle due to chemical disequilibrium. 
Construction of the neo-volcanic area of a slow-spreading ridge in a cold mantle context: Mid-Atlantic Ridge Eastern Intersection with Romanche Transform Fault
Authors: Grenet Léa , Maia Marcia , Hamelin Cédric , Briais Anne , Brunelli Daniele
Published: February 2023

At mid-oceanic ridges, mantle temperature and magma supply influence the structure of the neo-volcanic zone. Due to the large Romanche offset, a strong “cold edge” effect is present at its eastern intersection with the Mid-Atlantic Ridge. This effect decreases with the distance from the transform fault, making this region an ideal area to study the impact of the thermal gradient on the architecture of the neo-volcanic zone. We analyzed seafloor videos and photos from submersible dives, as well as bathymetry and backscatter data collected during the SMARTIES cruise (2019), from the Ridge-Transform Intersection (RTI) to approximately 80 km to the south of it. We produced maps at local and regional scales and quantified the morphology of volcanoes (height, diameter, height/diameter ratio, volume and surface). Visual observations have showed that the seafloor is mainly made up of pillows or elongated pillows and rare massive lava flows. Within 30 km of the RTI, the neo-volcanic area is characterized by clusters of volcanoes, affected by faults trending N120-130° E, oblique to the extension and to the transform fault orientation, and by faults trending E-W. At 30 km to 50 km from the RTI, the Central segment displays a robust volcanic ridge oriented N150°E built by a pilling of volcanoes and narrow ridges. Its eastern and southern parts are old and characterized by oblique faults and narrow ridges (N130-140°E), while the northwest portion is more recent, faults and ridges are almost normal to the extension. The southernmost segment, located at 80 km from the RTI, is orthogonal to the spreading direction and asymmetric, bounded at the west by a detachment fault. Recent volcanic edifices were observed from the center of the segment to the base of the detachment. Our observations suggest that the neo-volcanic area is fed by more and more magma from north to south. This increase in magma supply is marked by a more structured volcanic axis, volcanoes that are more voluminous and a change in the orientation of the segments and faults. Changes in the orientation of faults and off-axis abyssal hills also reveal variations in the magmatic supply over time.
Functional response evaluation of hard and soft adaptation strategies in urban flooding
Authors: Borah Angana , Dave Raviraj , Bhatia Udit
Published: February 2023

Intensified climate extremes in changing climate scenarios with rapid urbanization make urban floods a global concern since the population in the cities is increasing. One way to manage urban floods is the adoption of various adaptation measures. The existing infrastructures for flood adaptation are classified as 'hard,' 'soft,' and 'hybrid' adaptation strategies, which constitute the conventional Stormwater Drainage Network (SWD),  Green Infrastructures (GI) practices, and a combination of soft and hard strategies, respectively. As infrastructures are vulnerable to damage because of exceedance in design life, capacity, or any adverse situation, all adaptation methods are likely to become non-functional in the event of a disaster. Under such circumstances, the flood response of an urban region on account of the non-functionality of both soft and hard adaptation strategies is not well understood. We develop a coupled 1D-2D hydrodynamic model using MIKE+ and generate scenarios to compare the damages in the functional capacity of all three adaptation strategies. We implement this model for Ahmedabad city, India, and our Initial results show the hotspots which are highly prone to urban flooding. Here, we evaluate the hydrodynamic interaction between flood propagation on the surface with components of SWD structures and GI facilities and determine the consequence of their functional damages. Our analysis unfolds all the aspects of utilizing certain adaptation pathways, including the merits and demerits of the success and failure of a project. Our framework could aid in determining the trade-offs between different adaptation pathways from the perspective of building flood-resilient cities. 
InSAR-AI-Based Approach for Groundwater Level Prediction in Arid Regions
Authors: Khodaei Behshid , Hashemi Hossein , Naghibi Seyed Amir , Berndtsson Ronny
Published: February 2023

Lake Urmia, located in northwestern Iran, is the largest salt lake in the Middle East (ME) and one of the largest hypersaline lakes in the world. The lake has an important role in biodiversity preservation and the economic and cultural aspects of its surrounding region. Over the last two decades, the combined effects of climate change and anthropogenic activities have caused a significant depletion of lake water. The interaction of lake water and groundwater has motivated us to study the surrounding aquifers to determine the impact of human activities on the lake. The Shabestar plain located in the northeast of Lake Urmia is chosen as the research area for the current study. The goal is to find a Remote Sensing (RS) based method to estimate the changes in groundwater level, due to over-exploitation, both in time and space. We use a random forest algorithm to determine the contribution of different factors in the estimation of the aquifer’s hydraulic properties. Input data include the surface deformation rate produced by Interferometric Synthetic Aperture Radar (InSAR) technique between 2016 and 2022, weather-driven parameters including temperature, precipitation, soil moisture, normalized differential vegetation index, and evapotranspiration, and the hydrological factors including observed well and lake water levels. The built model is then used for estimating the spatiotemporal groundwater level changes throughout the aquifer. The groundwater level change and its relationship with the lake water surface is investigated. The model has the potential to be generalized in the estimation of groundwater depletion in similar aquifers.
The Impact of Meteorological Drought on Vegetation Health in the Middle Euphrates River Basin (Syria)
Authors: Mohammad Hiba , peli Marco , Barontini Stefano
Published: February 2023

Syria is now witnessing the dramatic effects of a multiyear drought that has been afflicting the country since 2006. The drought has impacted several regions, but the north-eastern Al Jazira region, corresponding to the Middle Euphrates River basin and considered the Syrian “breadbasket”, has been hammered particularly severely.With this paper we aim at contributing to the knowledge on the consequences of multiyear meteorological drought on food security in the basin of the middle range of the Euphrates River in Syria.Annual precipitation data were collected from 11 ground meteorological stations for the period 1983–2020 covering an area of 96800km2. Data were provided by the Syrian Ministry of Agriculture. In addition, the series of two satellite-based indices, namely Vegetation Condition Index (VCI) and Vegetation Health Index (VHI) were collected to analyse the vegetation responses to the meteorological drivers. These indices were downloaded at a resolution of 4-km for the time range 1983-2020, from the Centre for Satellite Applications and Research (STAR) of the National Oceanic and Atmospheric Administration (NOAA). The crop production data, including yields of cotton, wheat, and maize, were collected at provincial level over the period of 1983–2020 from Syria Statistical Yearbook.Recent changes in meteorological drought features (e.g., frequency and intensity) throughout Syria for the years 1983–2020 were assessed by means of the Standard Precipitation Index (SPI), to characterize the meteorological draughtiness for the Al-Jazira region.SPI was computed on a 12-month timeline to account for the delayed effect of rainfall deficiency on crop output. Commonly, agricultural droughts are evaluated using drought indices at these long timeframes (e.g., 18 and 24 months) because these longer timescales reflect the accumulated influence of meteorological drought that might alter soil water content and stream flow. The correlation matrices of the series of SPI, averaged at different time scales to focus on the effect of multiyear drought events, with the series of VCI and VHI, will be presented.This work is preliminary to the GIS application of simplified Benfratello’s water balance method (Barontini et al., 2021) to assess the proneness to water scarcity and the irrigation deficit of different areas of the basin.ReferencesBarontini, S., Rapuzzi, C., Peli, M., and Ranzi, R.: A GIS based application of Benfratello's method to estimate the irrigation deficit in a semiarid climate, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12936, https://doi.org/10.5194/egusphere-egu21-12936, 2021.
Assessment of radionuclide levels in drinking water from communities in the West Rand region of the Gauteng Province, South Africa
Authors: Mohuba Seeke , Abiye Tamiru
Published: February 2023

This research contributes to the protection of members of the West Rand communities from radiological harm emanating from drinking water through the establishment of radionuclide levels in drinking water and the associated health risks of ingestion. The long-standing history of gold mining and processing in the Witwatersrand Basin has resulted in an exponential increase in the amount of radionuclides released into the environment, including the water system. As such, it is paramount to ensure the public and environment are protected from any pollution related to gold mining. The aim of this study was to assess and quantify radionuclide levels in drinking water (groundwater and municipal water) and the health risks associated with the ingestion of the water in residential communities of the West Rand region. Activity concentrations of 238U, 235U, 234U, 232Th, 230Th, 228Th, 228Ra, 226Ra and 224Ra in 22 drinking water samples were determined using alpha spectrometry, which were subsequently used to evaluate the radiological risks related to the ingestion of 238U in the water. The results indicate that groundwaters largely contain elevated activity concentrations of most radionuclides owing to the untreated nature of the water as opposed to the municipal-supplied water. Similarly, annual effective dose and cancer morbidity and mortality risk estimates were found to be higher in groundwater. Annual effective dose estimates in all samples were well below the prescribed limit of 0.1mSv/y, with a range of 0.0237–0.3106 mSv/yr. Cancer morbidity and mortality risk estimates were higher in females than males in all samples due to the higher life expectancy of females. Nevertheless, all morbidity and mortality risk estimates were significantly lower than the prescribed radiological risk limit of 0.001. All sampled drinking water was found to be radiologically safe for human consumption. Based on the findings of this study, continuous monitoring of the drinking water with an emphasis on groundwater should be implemented to ensure that radionuclide levels and associated health risks remain below local and international prescribed regulatory limits. Keywords: Gold mining, drinking water, radionuclides, annual effective dose, cancer risk
Are there more than two end-members contributing to storm-events in small head-water catchments?
Authors: Brekenfeld Nicolai , Fovet Ophélie , Cotel Solenn , Faucheux Mikaël , Floury Paul , Fourtet Colin , Guillon Sophie , Hamon Yannick , Henine Hocine , Petitjean Patrice , Pierson-Wickman Anne-Catherine , Pierret Marie-Claire , Gaillardet Jérôme
Published: February 2023

Stream water chemistry at catchment outlets is commonly used to infer the flowpaths of water through the catchment and to quantify the relative contributions of various flowpaths and/or end-members during, e.g., storm events. For this purpose, the number and nature of these flowpaths or end-members are commonly defined a priori as part of the experimental design and previous knowledge, and their contributions are calculated based on the dynamics of the stream chemistry, with the inherent assumptions and uncertainties of this approach. Here, we present a methodology, which inverts this classical approach. We use the variability of the stream chemistry data to determine the minimum number of end-members needed and, more specifically, whether two end-members would be sufficient. In this methodology, we analysed the concentration-concentration relationships of several major ion combinations on the storm-event scale for multiple events, using a multi-year, high-frequency (< 60 minutes) timeseries of the major cations and anions from the outlet of two small (0.8 – 5 km²) french catchments with contrasting land-use (forest and mixed farming-cropping productions). The results indicate that a large number of storm-events (up to 92%) could be interpreted as the result of only two end-members, depending on the catchment and the ion combination used. These findings might help to revise some of the perceptual understandings of flowpath or end-member contributions in catchments during storm-events. In addition, they might stimulate the discussion about the definition of end-members or flowpaths in catchments, especially with regard to variable hydrological contributions.
Mapping stagnant ice and age in the Dome Fuji region, Antarctica, by combining radar internal layer stratigraphy and flow modeling
Authors: Wang Zhuo , Eisen Olaf , Chung Ailsa , Steinhage Daniel , Parrenin Frédéric , Freitag Johannes
Published: February 2023

The Dome Fuji (DF) region in Antarctica is a potential site for holding an ice record older than one million years. Here, we combine the internal airborne radar stratigraphy with a 1-D inverse model to reconstruct the age field of ice in the DF region. As part of the Beyond EPICA - Oldest Ice reconnaissance (OIR), the region around DF was surveyed with a total of 19000 km of radar lines in the 2016/17 Antarctic summer. Internal stratigraphy in this region has now been traced. Through these tracked radar isochrones, we transfer the age-depth scale from DF ice core to the adjacent 500 km2 region. A 1-D inverse model has been applied at each point of the survey to extend the age estimates to deeper regions of the ice sheet where no direct or continuous link of internal stratigraphy to the ice cores is possible, and to construct basal thermal state and accumulation rates. Through the reliability index of each model, we can evaluate the reliability of the 1-D assumption. Mapped age of basal ice and age density imply there might exist promising sites with ice older than 1.5 million years in the DF region. Moreover, the deduced basal state, i.e., melting rates and stagnant ice provide constraints for finding old-ice sites with a cold base. The accumulation rate ranges from 0.014 to 0.038 m a-1 (in ice equivalent) in the DF region, which is also an important criterion for potential old ice.
Observed Dynamic Topography and Cenozoic Magmatism of the Eastern Seaboard of Australia
Authors: Slay Philippa , White Nicky , Holdt Megan , Stephenson Simon
Published: February 2023

Topography and bathymetry on Earth is both isostatically and dynamically supported. The isostatic signal is dominantly controlled by variations in the thickness and density of crust and lithospheric mantle. Therefore the challenge is to identify the dynamic component of topographic support, which is caused by sub-plate density anomalies arising from convective mantle processes. Here, we exploit an observationally-led approach to determine residual (i.e., dynamic) topography across the Australian continent and its margins. Compilations of receiver function analyses, wide-angle/refraction seismic surveys and deep seismic reflection profiles are used to determine both crustal velocity structure and depth to Moho. A published compilation of laboratory measurements is used to convert crustal velocity into density. In this way, residual topography is carefully isolated and combined with existing offshore measurements. Australia’s isolation from plate boundaries combined with rapid northward translation suggest that long-wavelength dynamic topography is controlled primarily by the interaction of sub-plate convection and plate motion. Large-scale positive dynamic topography occurs along the eastern seaboard, which coincides with slow shear-wave velocity anomalies, positive long-wavelength gravity anomalies and Cenozoic basaltic magmatism. Geochemical modelling of both age-progressive and age-indepedent basalts suggests that the eastern seaboard is underlain by positive asthenospheric temperature anomalies and dramatically thinned lithosphere. These inferences are consistent with calibrated tomographic models, which show that the lithosphere is 60 km thick. In general, the pattern of continental dynamic topography is consistent with residual bathymetric anomalies from oceanic lithosphere surrounding Australia.
Toward last-minute warning of local aurora activity and large dB/dt in Kiruna
Authors: Busom Vidal Arnau , Yamauchi Masatoshi , Brändström Urban
Published: February 2023

In spaceweather warning, last-minute (< 10 min) warning of the local ionospheric and geomagnetic activities using local measurements is as important as midterm (about 1 hour using Sun-Earth L1 monitor) and long term (> day using solar data) warning. We the first step, we developed warning system for different levels auroral activities using all-sly camera data only: one is sudden and significant intensification of auroral arc with expanding motion (we call it "Local-Arc-Breaking"), and the other is activated local aurora which is often (submitted to Geoscientific Instrumentation, Methods and Data Systems: https://egusphere.copernicus.org/preprints/2022/egusphere-2022-331/).We now combined geomagnetic data to this warning. We used 1-sec geomagnetic (B) data to drive dB/dt, and took its average every minute to further separate the activity level of the aurora, from previous three levels (using only aurora) to seven levels. Here, the highest level (dB/dt > 5 nT/s) means potential risk of hazard by high geomagnetic induced current (GIC).We then obtained probability of having higher level of the activity within the following 15 minutes. Particular interest is the probability of Local-Arc-Breaking from precursors (four different levels) and large dB/dt (> 5 nT/s) event. Since the rise time of big activities (both aurora and dB/dt) is very short, nearly half the case of such occurrence is within one minutes, and 10 minute is sufficient. For the data we used winter 2021/2022 season data (from November 2021 to April 2022). The data is limited because we have different camera before. Out of four possible precursors, three precursors give 50-70% probability of the Local-Arc-Breaking within 10 minutes. Once the auroral activity level reaches the Local-Arc-Breaking, and if dB/dt exceed 2 nT/s, we expect large dB/dt > 5 nT/s with 20% (with large uncertainty for the last one). This opens up a possibility of using auroral data in improving the prediction of the GIG events.
Changes in thunderstorm activity at high latitudes observed at WMO weather stations
Authors: Kępski Daniel , Kubicki Marek
Published: February 2023

Knowledge about the occurrence of thunderstorms in polar regions is still limited. Lightning detection systems have varying detection efficiency over time and space, which makes climatological analysis difficult. This is especially problematic in areas where lightning strikes are relatively rare. Traditional observations carried out at weather stations are therefore still a very important source of information about the occurrence of thunderstorms in the polar and circumpolar regions. Scientific studies usually predict that these phenomena will be more frequent in high latitudes in a warmer world. To check whether the number of thunderstorms changes as projected, we summarize SYNOP data from manned World Meteorological Organization (WMO) stations operating in the years 2000-2019 located at latitudes above 60° of both hemispheres. According to this source, the changes in thunderstorm frequency are only visible in certain areas and mostly during the summer months. The regional Kendall test revealed a statistically significant increase in the number of thunderstorm days north of 60°N in Interior Alaska, northwestern Canada, much of Siberia and European Russia. However, a decrease in thunderstorm frequency has also been detected in some regions. This was the case on the shores of the southern Norwegian Sea and seasonally in spring in the northern Urals. The largest increase in thunderstorm days exceeded 5 per decade in the highly continental regions of central Siberia and interior Alaska. For the entire high-latitude area, the change in the number of days with thunderstorms was statistically insignificant. However, the statistically relevant increase in the number of thunderstorm days is visible for inland weather stations located 250 – 1,000 km from the coastline, where it was on average 1 day per decade.
Signature of monsoon driven salinity fluctuations in stable isotope (oxygen and carbon) record of bivalve shells: Insights from the sclerochronology of three confluent individuals from the Bay of Bengal, India
Authors: Dutta Saurav , Chattopadhyay Devapriya
Published: February 2023

Stable isotope (δ18O and δ13C) record of the shells of Crassostrea has served as trusted sclerochronological recorders for deciphering the life history and the interannual ambient seawater conditions including temperature and salinity. Several species of Crassostrea are found in modern estuarine system throughout the world. The Bay of Bengal (BOB) in the northern Indian ocean is one such region which experiences the lowest salinity in the tropics due to exceptional and complex hydrological dynamics associated to the Indian monsoon. In this study, we utilized three shells of the endemic species, that are cemented together.  We collected the specimens from Chandipur-on-sea BOB, in the eastern coast of India to understand the relationship between isotope signatures of the shells (δ18Oshell and δ13Cshell), growth history and the environmental parameters (temperature and salinity).In terms of the microstructural variation within the shells, samples collected from the foliated layer as compared to the chalky calcite layer of the cross sectional hinge region demonstrates no significant difference in their isotopic values. The theoretical isotope profile model based on the satellite data for monthly temperature and salinity data provided the background pattern which when compared to the observed isotope values demonstrated no significant difference for Cha 2 and Cha 3, however, the isotope value of Cha 1 shifted significantly towards negative values. The isotope profile for all the individuals are sinusoidal with repeating δ18Oshell and δ13Cshell minima in the form of relatively sharper and narrower negative half cycles and demonstrates negative offset from the predicted model someimes. We infer the negative shifts and offset of the isotope minimas to be attributed to the lower salinity due to river runoff and precipitation during summer monsoon in this region which also leads to slow or limited growth of the oysters. The grey foliated calcitic bands within the chalky calcitic layers do not incorporate the amplitudes or a particular trend of the isotopic profiles representing no seasonal signature and hence cannot be utilised as age indicators for C.cuttackensis. However, the count of minimas in the isotope profiles revealed the age to be slightly more than 1 year for Cha1 and Cha3 whereas Cha 2 lived for three years atleast. The corresponding growth rates for length and height of the shells decreases with ontogeny, more so for the length than height validating the elongated shape of C.cuttackensis in their adulthood. When compared, the calculated growth rates for C.cuttackensis is highest among all other present and past Crassostrea species globally.
Meso-scale landscape changes reconstructed from fluvial and alluvial sedimentological archives around the roman town Chimtou (Medjerda Valley), North Tunisia
Authors: Pagels Julia , von Rummel Philipp , Chaouali Moheddine , Bebermeier Wiebke
Published: February 2023

The settlement of Chimtou located in the Medjerda valley is known for its marble quarry, where yellow marble was mined for the entire roman empire. During the Roman period Chimtou has been a major roman city but little is known about the changes during the transition to the Arab period. The interdisciplinary project ISLAMAFR aims to understand the cultural, economic and landscape transformations of the western Medjerda Valley from late antiquity to the early medieval period (600 to 1000 AD).Earlier studies in the region by Christoph Zielhofer and Dominik Faust have shown that the landscape evolution of the Medjerda Valley derived from alluvial records indicates short-term changes in fluvial dynamics in the Holocene. During the upheaval from Roman to Arab period they reconstructed great flooding events for the Western Medjerda Valley with a brief slow-down in fluvial activity during the Arab conquest. On the basis of their work we will densify the landscape history using two fluvial and alluvial archives from the hinterland of Chimtou for the period from 600 to 1000 AD. We analyzed sediment cores in the laboratory from an infilled oxbow lake of the Oued Medjerda and a flood channel, which regularly overflows. The successive phases of channel infill of the archives allow us to reconstruct the fluvial activity and landscape changes in their surroundings. A multi-proxy approach was applied, integrating the analysis of the dated high-resolution sediment records with geomorphological mapping, archaeological records, and geological and topographical data. Coupling the long-term landscape changes with high resolved short-term landscape changes identifies the human-environmental interactions in the hinterland of Chimtou from late antiquity to early medieval period.  
A model of the weathering crust and microbial activity on an ice-sheet surface
Authors: Woods Tilly , Hewitt Ian
Published: February 2023

Shortwave radiation penetrating beneath an ice-sheet surface can cause internal melting and the formation of a near-surface porous layer known as the weathering crust, a dynamic hydrological system that provides home to impurities and microbial life. We develop a mathematical model, incorporating thermodynamics and population dynamics, for the evolution of such layers. The model accounts for conservation of mass and energy, for internal and surface-absorbed radiation, and for logistic growth of a microbial species mediated by nutrients that are sourced from the melting ice. It also accounts for potential melt-albedo and microbe-albedo feedbacks, through the dependence of the absorption coefficient on the porosity or microbial concentration. We investigate one-dimensional steadily melting solutions of the model, which give rise to predictions for the weathering crust depth, water content, melt rate, and microbial abundance, depending on a number of parameters. In particular, we examine how these quantities depend on the forcing energy fluxes, finding that the relative amounts of shortwave (surface penetrating) radiation and other heat fluxes are particularly important in determining the structure of the weathering crust. The results explain why weathering crusts form and disappear under different forcing conditions, and suggest a range of possible changes in behaviour in response to climate change. Time-dependent solutions of the model will also be discussed.
Challenges of fault characterization in areas of high anthropization. Surface variation along the Palomares Fault zone (SE Iberian Peninsula).
Authors: Molins-Vigatà Júlia , Ortuño María , Insua-Arévalo Juan Miguel , Martín-Banda Raquel
Published: February 2023

The study of seismogenic faults in low deformation rate regions is a challenging task, and their correct characterization is often limited due to the action of other external processes not related to the faults. Due to their lower rates, the expression of these structures is minor and more difficult to identify compared to regions with higher tectonic rates. Furthermore, in some areas, the erosion rates can be higher than the tectonic rates and the expression of the fault can be eroded easily. Another challenge is the exponential increase of surface modification due to anthropogenic processes, related e.g. to the placement of new infrastructures or agricultural activity. Anthropic modification of the landscape due to agriculture, farming, and greenhouses land covering is extremely high in the regions of Murcia and Almeria, where the major part of the main faults of the Eastern Betics Shear Zone (EBSZ) are located. The EBSZ is a low-to-moderate strain region situated in the SE of the Iberian Peninsula, a crustal-scale transpressive fault system that absorbs a significant part of the shortening between the Eurasian and the Nubian plates. Despite its low rates, it is the most active fault system on the Peninsula. The Palomares Fault (PF) is one of the principal structures of the EBSZ, bounding to the East the main Neogene-Quaternary basins of the area. At the foot of the bounding ranges, a high level of agricultural activity has taken place on top of the alluvial deposits. Therefore, in some areas where this activity is affecting the fault expression, it is required to work with historical aerial images in order to detect erased landforms. To overcome this limitation, some digital elevation models (DEMs) have been obtained with historical aerial photos through photogrammetry, as the current DEMs are not sufficiently useful. By this methodology, it is possible to detect some vertical fault slips now affected by agricultural activity, and the variation of the surface trough time. With GIS, the two models can be compared, subtracting the photogrammetric model from the current model. The result is a map showing the areas where the surface topography has increased or decreased. This analysis has been applied in zones where fault traces have been detected by historical images, but are currently unidentifiable due to anthropogenic activity.