bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional classification according to PM10 concentrations in the Seoul Metropolitan and Chungcheong Area, Republic of Korea
Authors: Choi Woosuk
Published: February 2023

Since the Seoul Metropolitan Area, Republic of Korea, is highly populated, a large number of people are frequently exposed to high concentrations of particulate matter (PM) with mean aerodynamic diameters of <= 10 mm (PM10) in cold season. The concentration of PM10 in Seoul Metropolitan Area increases by transboundary transport, local direct emissions, and chemical reactions of aerosol precursors in the atmosphere. Here, the Seoul Metropolitan Area (Seoul, Gyeonggi-do, and Incheon) and surrounding region (Chungcheongnam-do, Daejeon, and Sejong) are regionally classified by clustering analysis based on the variability of PM10 concentrations. According to the inertia score by the number of clusters, the optimum cluster number of regional variability of PM10 is four. The region of cluster 1 is divided into southern Gyeonggi-do and eastern Chungcheongnam-do, the cluster 2 is mainly classified Incheon, western Gyeonggi-do, and Seoul. The cluster 3 region is western Chungcheongnam-do adjacent to Yellow Sea, and the cluster 4 is classified into eastern Gyeonggi-do. The variability of PM10 in each region is distinguished by the local chemical pollutants emission and weather conditions such as wind speed and direction in each region. This regional classification of PM10 variability is different from administrative districts. Considering most of policies for responding to high concentrations of PM10 are being prepared by administrative districts, this study suggests that a response on the basis of these regional PM10 distribution would be more effective way to improve air quality in the Seoul Metropolitan and Chungcheong Area.
The seedy underbelly of yield: how measuring verrrrrry slow grain motion changes our view of landscapes
Authors: Jerolmack Douglas , Deshpande Nakul
Published: February 2023

It is now well established that many lansdcapes are organized to be close to the threshold of sediment motion: rivers, wind-blown dunes and hillslopes. Whether explicitly or implicitly, this threshold is almost universally treated as a Mohr-Coulomb failure criterion, which is an opaque barrier that prevents us from viewing and understanding motion beneath the yield point. Below-threshold motion is creep, and the dynamics are creepy indeed: typical continuum descriptions break down, and observed behaviors can be counterintuitive. In this talk I present two experiments, using two different optical techniques, that study very slow particle motions below the threshold of motion. Experiments in a scaled-down river use refractive-index matched scanning to image the interior of a sediment bed sheared by a fluid, and track particles over many orders of magnitude in velocity to show that creep is activated deep into the sediment bed. This creep hardens the bed and drives segregation. Tracking creeping grains becomes impractical, however, as it takes several months to measure the slowest particle motions. To overcome these simplifications and expand our study of creep, we examine an apparently static sandpile that is isolated from external disturbance. Instead of particle tracking, we use an optical interferometry technique called Diffusive Wave Spectroscopy (DWS) that allows us to measure creep rates as low as nanometers/second. Viewed through the lens of DWS, the model hillslope is alive with motion as internal avalanches of grain rearrangements flicker throughout the pile. We observe similar dynamics to those observed in the river experiment -- albeit over much shorter timescales -- even though the only significant stress is gravity. What causes these grains to creep below their angle of repose? Observations suggest that minute mechanical noise may play a role, but reducing the noise floor beyond our fairly quiescent conditions is very challenging. Instead, we raise the driving stresses through heating, tapping and flow. The observations lead to new view of sediment creep as relaxation and rejuvenation of a glassy material, where mechanical noise plays a role akin to thermal fluctuations in traditional glass materials. Sub-yield deformation is a new world to explore, for those patient enough to look for it. 
Intermittent Behavior in the AMOC-AMV Relationship
Authors: Bellucci Alessio , Mattei Denis , Ruggieri Paolo , Famooss Paolini Luca
Published: February 2023

The connection between the Atlantic meridional overturning circulation (AMOC) and the Atlantic multidecadal variability (AMV) is inspected in a suite of pre-industrial integrations from the 6th phase of the Coupled Model Inter-comparison Project (CMIP6), using a change-point detection method to identify different AMOC-AMV co-variability regimes. A key finding of this study is that models robustly simulate multi-decadal windows where the AMV and the AMOC are essentially uncorrelated. These regimes coexist with longer periods with relatively high correlation. Drops and recoveries of correlation are found to be often abrupt and confined in a temporal window of the order of 10 years. Phenomenological evidence suggests that the no-correlation regimes may be explained by drops in the variance of the AMOC: a less variable meridional heat transport leads to a suppressed co-variability of the AMV, leaving a larger role for non-AMOC drivers, consistent with a non-stationary AMOC-stationary noise interpretative framework.
The latitudinal shift of the midlatitude atmospheric circulation in response to climate change and the role of midlatitude diabatic heating
Authors: Ghosh Soumik , Lachmy Orli , Kaspi Yohai
Published: February 2023

Previous studies showed that the midlatitude atmospheric circulation generally shifts poleward in response to climate change induced by increased greenhouse gas concentration, including the midlatitude storm track and the eddy-driven jet. The magnitude of this shift varies widely between different climate models and depends on the season, hemisphere and longitude. In this study we aim to reexamine the connection between the shifts of the sensible eddy heat flux and the eddy-driven jet in response to climate change and the role of diabatic heating and latent eddy heat flux in this relation. Our approach is to use the constraints of the zonally averaged heat and momentum budgets in order to connect the eddy-driven jet latitude to the heat budget terms. First, we examine the relation between the eddy-driven jet latitude and the eddy heat flux latitude in the inter-model spread of CMIP6 models. We find that the latitudinal separation between the eddy heat flux and eddy-driven jet depends on the amount of diabatic heating in the midlatitude midtroposphere, which varies widely between different models. This relation is explained based on the heat and momentum budgets.
Next, we use an idealized general circulation model with interactive water vapor and full radiation. We customized the model with different levels of saturation vapor pressure by increasing CO2 concentration and by increasing the humidity factor in the Clausius-Clapeyron relation. We found that in both the cases the atmospheric circulation responds in a similar way and the heat budget terms shift upward and poleward, signifying an upward and poleward shift of the storm track. We found that when the diabatic heating rises upward and strengthens enough over the midlatitude mid-troposphere in response to climate change, the adiabatic cooling by the Ferrel cell rising branch balances the diabatic heating and an equatorward shift of the eddy driven jet and the Ferrel cell is observed. These results provide further insight to the relation between the responses of the midlatitude circulation and the poleward energy flux terms to climate change.
Experiment of filling the data gaps for better geoid determination: Case Study for Egypt (Africa)
Authors: Abd-Elmotaal Hussein , Kühtreiber Norbert
Published: February 2023

The coverage of the gravity data plays an important role in the geoid determination process. Still some parts in the world have poor gravity data coverage, with sometimes, large data gaps. Egypt (representing the situation in Africa) has sparse gravity data coverage over relatively large area. This paper tries to answer which type of gravity field signals at which resolution for filling the gaps would give the best geoid determination precision. This outcome is essential for the IAG sub-commission on the gravity and geoid in Africa in order to determine the African geoid with the best possible precision. Different types of gravity field signals have been used. They are gravity, geoid undulation and deflections of the vertical. Different resolutions of these signals are tested. The computed geoid precision for each case has been determined through the least-squares collocation technique (Moritz 1980). The results are shown and comprehensively discussed.
Occurrence, fate, and risk assessment of N-nitrosamines in groundwater and river water in an agricultural area
Authors: Chen Yingjie , Huang Huanfang , Chen Wenwen , Huang Xuelian , Qian Zhe , Qi Shihua
Published: February 2023

N-nitrosamines have been frequently detected in natural waters as a kind of nitroso compound with significant carcinogenic effects on humans. In remote agricultural areas, groundwater is often consumed directly due to inadequate water supply systems, necessitating the investigation of the occurrence, sources, and cancer risk of N-nitrosamines in the groundwater of agricultural areas. This study identified eight N-nitrosamines in groundwater and river water in the Jianghan Plain, a popular agricultural area in central China. The total concentrations of N-nitrosamines in the groundwater and river water were <2.3~61 ng/L and 3.2~10 ng/L, respectively. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMOR), N-nitrosopyrrolidine (NPYR), and N-nitrosodi-n-butylamine (NDBA) were detected in groundwater, with the main compound being NDMA (up to 52 ng/L). These N-nitrosamines were also detected in river water at comparable concentrations. The significant negative correlations between N-nitrosamines and water temperature/DO indicated that aerobic biodegradation had an influence on the N-nitrosamine distribution. Ammonium (NH4+) was proven not to be a N-nitrosamine precursor, and it rarely reacts with the precursors to form N-nitrosamines. NH4+ and NDBA have similar sources in the JHP. Nitrite (NO2-) could consume active hydroxyl radicals, which played a decisive role in forming N-nitrosamines from the ozonation of secondary amines, rather than react with secondary amines when the concentration of NO2- was low. In the case of high NO2- concentrations, NO2- reacts with amines in the environment to form N-nitrosamines. The concentrations of NDMA, NDEA, and NDBA precursors were higher in groundwater than in river water, as suggested by the formation experiment. Redundancy analysis and multiple linear regression analysis results showed the primary source of N-nitrosamines by applying nitrogen fertilizer and specific N-nitrosamines such as NPYR carried by pesticides in groundwater. The average (1.08 × 10-5) and maximum (8.18 × 10-5) total cancer risk values of detected N-nitrosamines were higher than the accepted risk level (10-5), suggesting a potential carcinogenic risk of contaminated groundwater. To minimize N-nitrosamine contamination in the groundwater of agricultural areas, further research on selecting pesticides and fertilizers that are heavily used is urgently needed.
Experimental model of cerussite PbCO3 replacement by mimetite Pb5(AsO4)3Cl at pH 2 – 8
Authors: Stępień Ewa , Manecki Maciej
Published: February 2023

The mobility of arsenic in aquatic environments is controlled by oxidation states of arsenic, stability of solid phases, and chemical composition of water (Meng et al., 2002). Binding of arsenic in the environment may occur through precipitation of low-solubility salts (Magalhães, 2002), like mimetite Pb5(AsO4)3Cl. The aim of this study is to experimentally investigate reactions between cerussite (PbCO3) and solutions containing AsO43- at various conditions favouring mimetite formation. These observations may provide a new recognition for As immobilization, which might be relevant in remediation of contaminated natural waters.The mechanism of cerussite reaction with arsenate solutions (50 mg As/L) was studied at pH 2 – 8 using synthetic cerussite powder and fragments of natural cerussite crystals (Mibladen, Morocco). The reaction was carried out by direct contact of 500 ml of As-containing solution with PbCO3, in presence of Cl- ions.Cerussite was reacted for up to 4 weeks at in situ and ex situ setups. X–Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM-EDS) and Electron Microprobe Analysis (EMPA) were used for analysis of the solid products of the experiments. The solutions were tested for Pb with Atomic Absorption Spectroscopy (AAS) and for AsO43-  using colorimetry.Precipitation of mimetite on cerussite powder crystals is observed already after 1 day of the reaction with arsenate solutions, at the whole range of pH. Mimetite forms hexagonal rods or needles less than 1 µm in size precipitating in the form of incrustations on PbCO3 crystals. Their size depends on the pH: a fine-grained precipitate forms at higher pH. Observations of natural crystals show replacement of cerussite by polycrystalline mimetite crust. The crust made of columnar and needle crystals is porous allowing for solution penetration and progress of the reaction. The replacement features indicate similarity to pseudomorphic reactions, and the mechanism elucidated as interface coupled dissolution - precipitation. Overall, cerussite replacement by mimetite reduces AsO43- concentration from 50 ppm to below 1 ppm. It also depends on the pH.This research was funded by AGH University of Science and Technology project No 16.16.140.315.Magalhães, M. C. F. (2002). Arsenic. An environmental problem limited by solubility. Pure and Applied Chemistry, 74(10), 1843–1850.Meng, X., Jing, C., & Korfiatis, G. P. (2002). A Review of Redox Transformation of Arsenic in Aquatic Environments. Biogeochemistry of Environmentally Important Trace Elements, 70–83. 
Spatial representation learning for ensemble weather simulations using invariant variational autoencoders
Authors: Chen Jieyu , Höhlein Kevin , Lerch Sebastian
Published: February 2023

Weather forecasts today are typically issued in the form of ensemble simulations based on multiple runs of numerical weather prediction models with different perturbations in the initial states and the model physics. In light of the continuously increasing spatial resolutions of operational weather models, this results in large, high-dimensional datasets that nonetheless contain relevant spatial and temporal structure, as well as information about the predictive uncertainty. We propose invariant variational autoencoder (iVAE) models based on convolutional neural network architectures to learn low-dimensional representations of the spatial forecast fields. We specifically aim to account for the ensemble character of the input data and discuss methodological questions about the optimal design of suitable dimensionality reduction methods in this setting. Thereby, our iVAE models extend previous work where low-dimensional representations of single, deterministic forecast fields were learned and utilized for incorporating spatial information into localized ensemble post-processing methods based on neural networks [1], which were able to improve upon model utilizing location-specific inputs only [2]. By additionally incorporating the ensemble dimension and learning representation for probability distributions of spatial fields, we aim to enable a more flexible modeling of relevant predictive information contained in the full forecast ensemble. Additional potential applications include data compression and the generation of forecast ensembles of arbitrary size.We illustrate our methodological developments based on a 10-year dataset of gridded ensemble forecasts from the European Centre for Medium-Range Weather Forecasts of several meteorological variables over Europe. Specifically, we investigate alternative model architectures and highlight the importance of tailoring the loss function to the specific problem at hand.References:[1] Lerch, S. & Polsterer, K.L. (2022). Convolutional autoencoders for spatially-informed ensemble post-processing. ICLR 2022 AI for Earth and Space Science Workshop, https://arxiv.org/abs/2204.05102.[2] Rasp, S. & Lerch, S. (2018). Neural networks for post-processing ensemble weather forecasts. Monthly Weather Review, 146, 3885-3900.
Operational Algorithm of Aerosol Effective Height from the Geostationary Environment Monitoring Spectrometer (GEMS)
Authors: Park Sang Seo , Kim Jhoon , Cho Yeseul , Park Junsung
Published: February 2023

The Geostationary Environment Monitoring Satellite (GEMS) retrieves several species of trace gases and aerosol properties. For the aerosol property, retrieval results from the GEMS can be used for the surface air quality analysis and aerosol effect for the airmass factor (AMF) calculation. To provide accurate information on aerosol, in addition, aerosol vertical information is also retrieved from the GEMS defined by the aerosol effective height (AEH). The AEH can help to estimate the AMF for tropospheric trace gases and surface concentration of particulate matter (PM). The aerosol vertical distribution is relatively difficult to retrieve compared to those of clouds, because the optical property of aerosol is various due to the various aerosol types in the atmosphere. For the UV-visible hyperspectral observation, the aerosol vertical distribution can estimate from the absorption bands based on the Oxygen molecules, such as O2-A, O2-B, and O2-O2 absorption. Because of the limitation for the spectral coverage from 300~500 nm, however, GEMS is only available to use O2-O2 absorption bands. For the possibility of the AEH retrieval algorithm from GEMS, Park et al. (2016) investigated the theoretical sensitivity test of the AEH retrieval by solely using the O2-O2 absorption band with considering the aerosol and surface properties. Based on the previous studies, we introduce the operational retrieval algorithm for AEH with the theoretical basement. Also, we showed the performance of the operational AEH algorithm from GEMS based on case studies and the validation study using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP).
Coupled patterns of foraminiferal species richness and mega-climatic change across the Eocene-Oligocene transition
Authors: Lu Zhengbo , Fan Junxuan
Published: February 2023

The Eocene-Oligocene transition (EOT) is the turning point of Earth’s Cenozoic climate, during which it stepped into the current “icehouse” state. The absence of a high-resolution, global, evolutionary timeline has limited understanding of the linkages between marine biodiversity and this environmental change. Here, we present a new 28-Myr-long foraminiferal species-richness history with an average temporal resolution of ~26 kyr based on a global dataset and quantitative stratigraphic method, CONOP. A significant richness decline accompanied the EOT, eliminating a great number of foraminifera species. The extinction events in planktonic foraminiferal (PF) and larger benthic foraminiferal (LBF) near the EOT appear to be associated with the combination of a rapid decrease in deep ocean temperature, a eustatic sea-level fall and a positive carbon isotopic excursion. In contrast, the much longer richness decline of small benthic foraminifera (SBF) across the EOT occurred in two phases: the first coincided with turnover of marine primary producers, and the second appears to have been temporally coincident with Afar-Arabian LIP activity, which led to expansion of oceanic anoxia and euxinia. Thus, mega-climatic changes are reflected in the species richness of foraminifera during the Eocene-Oligocene “warmhouse-icehouse” transition.
AtmoFlow: Thermo-electrohydrodynamic convection in the thermally driven spherical shell with differential rotation
Authors: Gaillard Yann , Szabo Peter , Egbers Christoph
Published: February 2023

In a geophysical point of view, large scale prediction of atmospheric flows become more and more important to forecast e.g. extreme weather conditions that are observed in recent days more frequent and may relate to the overall climate change.  The AtmoFlow experiment is a small scaled laboratory spherical shell to investigate such atmospheric flow fields in a miniaturized model of a planet. Besides this physical experiment, numerical simulations are performed to analyze the resulting convective patterns in more detail. The experiment is composed of two spherical shells, which can rotate independently. The temperature on the shell's surface can be defined as a heated equator and a cooled pole. To model the terrestrial gravitation, an electric potential is applied on a dielectric fluid confined between the shells. This so called dielectrophoretic force triggers the formation of buoyant patterns, and is in fact the artificial equivalent of terrestrial gravitation. The simulations are processed with a custom programmed solver in the OpenFOAM ecosystem. It covers all predefined rotation combinations starting with no rotation, solid body rotation and differential rotation. The latter are the latest results of the computational simulation campaign and used to investigate the influence of the artificial central force field to differential rotation. While differential rotation can cause the well known Taylor vortices, it has to be noted that the cell formation induced by the central dielectrophoretic force field maybe significantly extubated and thus new convection patterns may arise.  This in fact is the overall focus of this study to understand the underlying physical process of such pattern formations. The analyses focus first on the amount of convective heat that these patterns are able to transport, and second to quantify their shape and intensity via a spatial Fast Fourier Transformation to identify the most dominant structures. Finally, statistical moments will provide an estimation about the shape and location of vacillating patterns.
Utilization of petrogenic organic carbon in Arctic Fjord sediments
Authors: Ruben Manuel , Hefter Jens , Schubotz Florence , Geibert Walter , Butzin Martin , Gentz Torben , Grotheer Hendrik , Forwick Matthias , Szczuciński Witold , Mollenhauer Gesine
Published: February 2023

Fjords have been identified as carbon burial hotspots, sequestering about 18 MtC annually, with most recent estimates suggesting 61±16% of sedimentary organic carbon (OC) to be labile. Towards higher latitudes and catchment glaciation the relative contribution of petrogenic OC increases in fjord sediments. Enhanced melting and mass loss due to anthropogenic climate change is expected to increase sedimentary runoff from glaciers and ice-sheets in the coming decades, including previously locked-up petrogenic OC. Since petrogenic OC has an accumulated history of pre-depositional degradation, sequestration, and diagenesis, it has commonly been regarded as non-bioavailable to today’s microbes and is typically not considered a carbon source in climate models. However, over the last two decades, several studies discussed microbial utilization of petrogenic OC. While glacially derived dissolved OC was identified as being highly bio-available in the water column, the bio-availability of its particulate counterpart is virtually unexplored, especially after redeposition. To investigate the bio-availability of sedimentary petrogenic OC and its carbon feedback potential to the atmosphere, we extracted and determined intact polar lipids (indicative of living microbes) and their radiocarbon signature down core in three sediment cores in a proximal-to-distal transect in Hornsund fjord, Svalbard. By applying an isotope mass balance, we were able to show that local subsurface bacteria use between 5 ± 2% and 55 ± 6% (average of 25 ± 16%) of petrogenic OC for their biosynthesis. Thus, providing evidence that particulate petrogenic OC is bio-available after redeposition and is used as an important substrate in the subsurface. This suggests a potential positive feedback of increased petrogenic OC supply to fjord sediments via its bacterial utilization and subsequent carbon release in a warming climate. Further, we observe increased bio-availability of petrogenic OC along both the distal-to-proximal transect and down core. We hypothesize that the spatial and temporal variability of petrogenic carbon utilization is related to the availability of recently synthesized marine OC as well as to the distance to glacial termini, thus to sediment accumulation rate and oxygen availability.
Reconstruction of landforms using historical and recent aerial photographs for landscape evolution of coastal dune dynamics
Authors: Özcan Orkan , Özpolat Emrah , Akay Semih , Özcan Okan , Görüm Tolga
Published: February 2023

The Çukurova Delta Complex, which is located in the south of Turkey along the northeastern corner of the Mediterranean Sea, is the second-largest delta system in the Mediterranean. The Seyhan River flowed 10 km east from its current course until at least the 16th Century, and shifted to its current course in the west and began to build the modern delta and the youngest foredune ridges were formed by a combination of aeolian and littoral processes. Morphometrics of foredunes greatly contributes to understanding the relationship between aeolian and marine dynamics. High-resolution digital elevation models (DEMs) are important in examining the geomorphic features of foredune ridges because the low-relief delta environment makes it difficult to use standard topographic maps. Therefore, in the study, the morphometric features, including foredune height, foredune slope, foredune width, the space between foredune ridges, and beach width of the ridges within the study area were extracted from the DEM and orthophotograph of historical and recent aerial photographs. Structure from Motion (SfM) techniques allow for the reconstruction of present and past landforms, and to detect long-term topographic changes in the low-relief areas using historical and modern aerial images. A total of 27 aerial photographs were acquired from flights in AD 2016 covering the study area with a ground sampling distance of 0.3 m, while 13 archive analog aerial photographs with a ground sampling distance of 0.7 m were available from flights in AD 1950. Analysis of SfM-derived high-resolution DEM for the Seyhan Delta shows at least 25 foredune ridges inland for 4 km. It is very important to know the origin and morphodynamics of ridges in terms of revealing the coastal evolution of the Seyhan Delta. Since these ridges preserve past shoreline positions Holocene foredune ridges in the study area can be used to help reconstruct the nature of paleoenvironmental change. 
Steady subtropical terrestrial aridity since Pangea
Authors: Li Zhibo , Hu Yongyun
Published: February 2023

Modern terrestrial aridity affects billions of peoples’ lives and is projected to be severe in a warming future. Former works concentrated on aridity changes in the future, while deep-time paleoclimate simulations and proxies provide a new perspective for us to fully understand the evolution of terrestrial aridity. Distributions of arid and humid regions have strong implications for the existence of geological proxies, such as evaporites and coals. A systematic study of the land-sea distribution and aridity evolution has strong benefits to both science and industry. Here, we use Community Earth System Model version 1.2.2 (CESM 1.2.2) to investigate the evolution of terrestrial aridity since the supercontinent Pangea period. Simulation results show that the terrestrial arid regions are always concentrated in the subtropics, and the larger the subtropical land, the larger the arid region. During the Cretaceous when the Pangea breaks up completely, the arid/semi-arid area decreases evidently. The semi-arid area is proven to significantly expand under CO2-induced global warming, which is due to the dominant contribution from enhanced potential evapotranspiration. It is concluded that the geologic evolution of terrestrial aridity is dominated by subtropical land area, then by land fragmentation and CO2 concentrations.
Experimental study of a circular economy system for the oxidation treatment of organochlorine compounds
Authors: Cappelli Chiara , Rosell Mònica , Torrentó Clara , Usieto María , Soler Gil Albert
Published: February 2023

The acknowledgment of the serious hazard caused by the massive use of pesticides and other industrial and commercial products containing organochlorine compounds has prompted the search of the best strategy for the remediation of aquatic and terrestrial environments. Organochlorine compounds are persistent contaminants present in soils and water that easily bio-accumulate and bio-magnify becoming a threat for human health1.  The in situ chemical oxidation (ISCO) has proven to be an effective method for the decontamination of chlorinated solvents2. The ISCO implementation needs specific oxidant-activation conditions that are often difficult to maintain. In a previous study, inert urban waste (concrete residue) was used in a pilot system of circular economy to induce alkaline conditions in interception trenches installed in the unsaturated zone of a contaminated bedrock aquifer3. In the present study, a scaled down set-up was used to produce preliminary data on the solid reactivity and solution changes upon the application of an oxidant, persulfate, which requires alkaline activation. Flow-through columns were filled with grinded concrete waste that was allowed to react with water extracted from the trenches and enriched with persulfate. The results set the basis for the correct in situ application of the planned remediation method.  1. Islam, M. A.; Amin, S. M. N.; Rahman, M. A.; Juraimi, A. S.; Uddin, M. K.; Brown, C. L.; Arshad, A. Environmental Nanotechnology, Monitoring & Management 2022, 18, 100740.2. Krembs, F. J.; Siegrist, R. L.; Crimi, M. L.; Furrer, R. F.; Petri, B. G. Groundwater Monitoring & Remediation 2010, 30, (4), 42-53.3. Torrentó, C.; Audí-Miró, C.; Bordeleau, G.; Marchesi, M.; Rosell, M.; Otero, N.; Soler, A. Environmental Science & Technology 2014, 48, (3), 1869-1877.
Do droughts and floods pose similar risks to Sahel staple food crop?
Authors: Elagib Nadir A. , Ali Marwan M.A. , Schneider Karl
Published: February 2023

With its arid and semi-arid climate, the African Sahel is a region highly drought-prone and vulnerable given its reliance on meagre natural resources for food security. However, the region recently also experienced flood occurrences. Against the background of food security, effects of floods and drought upon crop yield requires thorough investigation. To investigate the risk that flood and droughts pose to food crop we considered: 1) the case of the Sudanese Sahel in the eastern part of the region given its representation of one-third of the total area of the region, 2) traditional rainfed farming systems as the most fragile system in terms of marginality and regular experiences of challenges, including weather shocks and 3) sorghum as a main staple crop in the area. To identify risk and quantify its magnitude during the years when yield losses were encountered, we used gridded climate datasets, dynamic (yearly) land-use datasets and an unusually long national sorghum statistics for the last half a century. We expressed risk in % as hazard x vulnerability x 100%. Using a drought index for the growing season based on the ratio of rainfall to potential evapotranspiration, hazard is expressed here as a function of: i) severity of drought, ii) dry spell and iii) time frequency of drought. For the 51-year period from 1970 – 2020, 26 risk years were identified representing both hydrological extremes – floods and droughts. A risk year is defined here as a year with yield loss below the detrended yield data. In the decade 2011-2020, seven years were identified risk years. Four of those (2011, 2012, 2013 and 2015) were drought years and three (2017, 2019 and 2020) were exceptionally wet years. Sorghum yield varied significantly as a function of risk. Variations in the risk index explain 97.5% of the variation in sorghum yield, with a 1% increase in the risk leading to a decline of yield by 14.5 kg/ha. Nevertheless, the traditional farming sector achieved several high yield levels during the 26 risk years, namely 2020, 2019, 2017 and 2015 were years with the 3rd, 4th, 5th and 7th highest yield levels. Our findings show that: a) the traditional farming system experienced a high degree of vulnerability to hydrological extremes during the decade 2011-2020 and b) drought remains the most relevant hydrological risk whereas floods cause a small risk and may even favor yield.
Multitemporal remote sensing to investigate saltwater intrusion impact on agricultural greening in the Po River Delta (Italy)
Authors: Luo Jian , Straffelini Eugenio , Tarolli Paolo
Published: February 2023

Agriculture along the coast depends on optimal water resource management, especially in delta areas. Indeed, freshwater aquifers close to the sea are at risk of saltwater intrusion, with disastrous consequences for crops. This is a complicated process that is the result of multiple factors, both natural and man-made. Droughts are responsible for particularly severe saltwater intrusion events. Indeed, lack of rainfall leads to reduced river flow, which favors the flow of marine water inland. Climate change is aggravating this condition in diverse parts of the globe. Therefore, it is crucial to investigate the process of saltwater intrusion in river deltas deeply. Although this phenomenon has already been addressed in the literature in some areas of the world, there is still much to be done to assess the effects of saltwater intrusion on crops at the sub-regional level. In this task, multi-temporal remote sensing opens up new horizons of knowledge. New Earth observation (EO) technologies make it possible to monitor the evolution of the process over several years of observation and vast areas. The open-source big data offered by international space programmes are an excellent starting point for understanding this trend. This study aims to examine the effects of saltwater intrusion on agricultural greening in the Po Delta (Italy), an important European food production area. The main economic activity in the area is agriculture, made possible by centuries of land reclamation and co-existing with wetlands of considerable ecological importance, now threatened by the salinization of the water. In fact, during dry summers, the Po River's flow rate decreases significantly, favoring the intrusion of saltwater for tens of kilometers inland, affecting irrigation systems and causing severe impacts on production. This study's analyses are based on the correlation between Po river water salinity at 47 sampling sites and NDVI values using Landsat 5. The research results could provide a low-cost, multi-temporal tool based on remote sensing to quantify/map the effects of saltwater intrusion on agriculture at the delta scale, helping stakeholders adopt a more efficient/sustainable use of freshwater near the sea.Acknowledgments - This study was carried out within the Agritech National Research Center and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022). The authors also thank the Start-up funding from Inner Mongolia University (21800-5223728).
Characterization of Earthquake Clustering in Contractional Regions, based on Nearest-Neighbor distances and Network Analysis
Authors: Peresan Antonella , Talebi Mohammad , Zare Mehdi
Published: February 2023

The features of earthquake clusters in two contactional domains, located in Northeastern Italy and North-Central Iran, have been investigated. The tectonic and seismicity of the two study areas, namely the Alps-Dinarides junction and the Alborz regions, are controlled by the convergence between the African and Arabian plates and the Eurasia plate. Both regions are characterized by a rather complex structural setting, mainly including reverse and strike-slip faulting systems, and by moderate to high seismic activity.The nearest-neighbor approach has been used for the identification of the earthquake clusters in the space-time-energy domain. This approach permits for a data-driven identification of clusters so that, within multi-event clusters, the features of secondary and higher orders dependent events can be explored. The investigation of seismicity in Northeastern Italy is based on bulletins compiled at the National Institute of Oceanography and Applied Geophysics (OGS) in 1977-2018, while in North-Central Iran the dataset was extracted from the catalog compiled by the Iranian Seismological Center (IRSC) for the period 1996-2022. According to preliminary analysis of the used earthquake catalogs, two corresponding regions have been identified, where a satisfactory completeness level is assessed for events with magnitude greater than 2.0. Robust values of the scaling parameters, namely the b-value and the fractal dimension of epicenters, have also been computed and are used to calculate the nearest-neighbor distances and to identify the earthquake clusters.The results obtained in the two regions confirm that the complexity of clusters structure depends on the tectonic, structural, and geophysical properties of the area. Moreover, the complexity measures, borrowed from network theory (i.e. the Centralization and Outdegree indexes), consistently capture the complexity of the identified clusters. Besides, in both investigated regions, the results allowed us identifying two macro-areas, which are characterized by different clustering features, namely: high complexity indexes,, which indicate simple (burst-like) structure of clusters, and low complexity indexes, corresponding to complex multi-level (swarm-like) structure of clusters. Specifically, we found that "swarm-like" (high complexity) sequences are prevalent along the thrust faulting Alpine and Central-West Alborz systems, whereas "burst-like" (low complexity) sequences prevail along the strike-slip Dinaric and Central-East Alborz domains.
Urbanization-induced vegetation cover loss and its impact on urban heat island and carbon emission in Kolkata megacity region, India.
Authors: Das Manob , Das Arijit , Pereira Paulo
Published: February 2023

Rapid urbanization has become a significant driver of land use and land cover (LULC) change and significantly affected hydrological, carbon cycle and ecosystem resilience in urban environments. The loss of vegetation cover driven by urbanization has a crucial impact on carbon emission (CE) and the urban heat island (UHI) effect resulting in global warming. This study aims to estimate the impact of vegetation loss on UHI and carbon emissions driven by urbanization in the Kolkata metropolitan area (KMA) in India from 2000 to 2020. This study employed remote sensing and a geospatial approach to monitoring the impact of vegetation loss on UHI and carbon emissions in KMA. The study's findings showed that the vegetation cover declined by about 60%, and the built-up area increased by about 185.94% from 2000 to 2020. The mean temperature from 2000 to 2020 increased by about 28%, and the areas with high and very high UHI intensity increased. The carbon emission from 2000 to 2020 increased by about 188.29%, with an average increase of 9.41% in the last 20 years in KMA. Carbon emission from built-up areas increased by about 185.94%, and carbon stocks decreased by about 59.91% from vegetation cover. The results also showed that normalized difference vegetation index (NDVI) had a negative impact on carbon emission and land surface temperature (LST), and UHI positively impacted carbon emission. This study suggests a few effective strategies to mitigate climate change and global warming effects, such as afforestation, reforestation and urban greening measures to increase city carbon sequestration capacity.
Ocean Bottom Seismic Survey in the Knipovich Ridge area
Authors: Czuba Wojciech , Mjelde Rolf , Murai Yoshio , Janik Tomasz
Published: February 2023

The structure of the oceanic crust generated by the ultraslow-spreading mid-ocean Knipovich Ridge still remains relatively uninvestigated compared to the other North Atlantic spreading ridges further south. The complexity of the Knipovich Ridge, with its oblique ultraslow-spreading and segmentation, makes this end-member of Spreading Ridge Systems an important and challenging ridge to investigate. The aim of this work is to better understand the lithospheric structure beneath the rare ultraslow-spreading ridges, using as example the Knipovich Ridge along its spreading direction. Ultraslow spreading ridges are characterized by a low melt supply. At spreading rates below 20 mm/y, conductive cooling effectively reduces the mantle temperature and results in less melt produced at larger depths. The Ocean Bottom Seismometer (OBS) data along a refraction/reflection profile (~280 km) crossing the Knipovich Ridge off the western Barents Sea was acquired by use of RV G.O. Sars on July 24 - August 6, 2019. The project partners are University of Bergen, Institute of Geophysics, Polish Academy of Sciences, and Hokkaido University. The seismic energy was emitted every 200 m by an array of air-guns with total volume of 80 l. To receive and record the seismic waves at the seafloor, ocean bottom seismometers were deployed at 12 positions with about 15-km spacing in 2 deployments. All the stations were recovered and correctly recorded data. Seismic energy from airgun shots were obtained up to 50 km from the OBSs. The profile provides information on the seismic crustal structure of the Knipovich Ridge and oceanic and continental crust in the transition zone. This profile is a prolongation of the previously acquired profile AWI-20090200 (Hermann & Jokat 2013) and together allow for the modeling of ~535 km long transect crossing the Knipovich Ridge from the American to the European plate. Seismic record sections were analyzed with 2D trial-and-error forward seismic modeling. This work is supported by the National Science Centre, Poland according to the agreement UMO-2017/25/B/ST10/00488. The cruise was funded by University of Bergen. Hermann, T. and Jokat, W., 2013. Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic. Geophys. J. Int., 193, 1399–1414, doi: 10.1093/gji/ggt048 
GeoCos v2.0: An open source web application for calculating Chance of Success values of exploration wells
Authors: Uyanik Ayberk
Published: February 2023

In hydrocarbon exploration, evaluation of a prospect’s success ratio relies on assessment of each petroleum system element and combination of it into a single risk factor. This makes estimation of chance of success values crucial to reduce the risks of exploration and to make robust investments for a particular region. To standardise this process, a couple of methods, both for global and basin-scale use, have been proposed in the last 20 years. All of them are table-based methods suggesting explorationists to pick the correct risk values according to the geological conditions they are encountering. However, examining the tables each time can be quite time-consuming. In addition, it can also cause subjective or biased picking of success values, resulting with under or overestimation of risk factors. To prevent repetition and miscalculations, GeoCos offers a web-based application by turning all table-based methods into interactive selection schemes. Users can choose geological conditions defined in table based methods and display the results. In addition, predictions of three table-based methods can be compared in spider or bar charts. Generated figures can be downloaded to implement them for publishment or presentations. There are direct links for the papers of the published methods as well.Development phase is consisted of two processes as front-end and back-end. Front-end development is based on HTML-CSS-Vanilla Javascript-Plotly.JS while for the back-end Node.JS completes the server side. Open source nature of this practical tool makes it easy to contribute for further developments. Source codes are available at the GitHub repository; https://github.com/Ayberk-Uyanik/GeoCos-v2.
Comparison of DAS surface waves records at geotechnical scales using telecom fiber optic with different cable and ground coupling
Authors: Gaudot Ianis , Leroy Matéo , Bitri Adnand , Bretaudeau François
Published: February 2023

It is now established that existing telecom fiber optic cables (FOC) may be used to record interpretable DAS seismic signals at seismological and reservoir scales, but their use at geotechnical scales remains an active topic of research.In this work, we present a comparison study of DAS surface waves records on a 600 m long FOC containing both tight and loose standard fiber optics spliced between each other. 2x300 m portion of the FOC are deployed next to each other horizontally at 40 cm depth in a shallow trench located along a road. The first 300 m portion of the FOC lays on the bottom of a PVC pipe (gravity coupling), and the second 300 m portion of the FOC is buried in the soil (soil coupling) ; so that a total of 4 couplings is tested along an optical path totalizing 1200 m: (1) gravity coupling on loose fiber optic, (2) soil coupling of loose fiber optic, (3) gravity coupling on tight fiber optic, and (4) soil coupling on tight fiber optic. We performed hammer shots recorded using DAS with 2.4 m, 4 m, 6 and 10 m gauge length. The resulting DAS data are compared to data from standard vertical and horizontal geophones regularly spaced along the line, as well as data from gimbal mounted vertical geophones towed behind a vehicle along the line.Our results show that gravity coupling on loose fiber optic using gauge length shorter than 5 m gives interpretable surface waves dispersion image up to 50 Hz for the fundamental Rayleigh wave mode, with a quality which is competitive with results from gimbal data. Therefore, our results suggest that the leveraging of existing telecom FOC for low-cost and fast geotechnical characterization is promising.