bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of gouge formation on seismicity and fault slip behavior. 
Authors: Castellano Miguel , Milanese Enrico , Cattania Camilla , Kammer David
Published: March 2024

Through the progression of seismic activity, natural fault zones undergo a complex evolution characterized by the accumulation of damage and the formation of gouge within the fault core across multiple scales. Even though this is believed to be among the key factors affecting the evolution of fault seismicity over time, a deep understanding of the mechanisms at play is still missing. In this study, we explore the role of gouge production in the self-organization process of loaded rough faults, focusing on the evolving dynamics of earthquake nucleation, recurrence and moment partitioning during the seismic cycle. We model the stress and sliding dependence of gouge evolution by linearly coupling Archard's wear law with rate-and-state friction through the critical slip distance ( Dc ). Including this new formulation in 2D quasi-dynamic, elastic simulations of rough faults, we can reproduce the effects of spatially and temporally heterogeneous gouge evolution. Following the build-up of gouge over many cycles, we observe a progressive transition from cascade-driven to creep-dominated nucleation processes, marked by an increase of precursory slow slip and foreshock activity. A clear shift in the moment partitioning from faster to slower slip rates becomes evident as heterogeneity grows larger, followed by a reduction of the total cumulative moment released. Finally, the recurrence interval is observed to grow initially, then drop abruptly and become more unpredictable as the amplitude of Dc continues to rise. Incorporating a new formulation of gouge production in earthquake cycles simulations, this work sheds light on the role of gouge accumulation in the maturation process of natural faults, offering critical insights for seismic risk assessment and mitigation.
Coupled Mesoscale to Microscale Simulations of Mixed-Phase Convective Clouds Observed during the Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE)
Authors: Kosovic Branko , Juliano Timothy , xue Lulin , Geerts Bart , Lackner Christian , Abrokwah Oteng Nathaniel
Published: March 2024

Equatorward excursions of cold polar air masses during cold air outbreaks (CAOs) result in the development of mesoscale convective circulations that significantly affect surface fluxes. Air masses undergo intense transformations as they transition from the ice to the warmer ocean.  Initially strong surface heat fluxes and strong shear result in the formation of helical convective rolls and associated cloud streets that can extend for hundreds of kilometers. Further downwind helical convective rolls evolve into convective cells forming open cell clouds.We study an intense CAO observed on 13 March 2020 during Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE) [1]. COMBLE deployed the Department of Energy Atmospheric Radiation Measurement (ARM) Mobile Facility 1 (AMF1) at Andenes, Norway to observe a range of CAO conditions. We simulate the evolution of a CAO using coupled mesoscale to microscale simulations with the Weather Research and Forecasting (WRF) model. The coupled simulation using WRF includes a mesoscale domain with 1050 m horizontal grid cell coupled online with a cloud-resolving LES domain with horizontal grid cell size of 150 m that stretches through the full ~1000 km extent of a CAO, from the ice edge to Andenes. Within the cloud-resolving domain are nested two LES domains with 30 m grid cells. One of these domains is focused on the region of convective rolls while the other one is focused on convective cells. This configuration enables us to study the transformation of airmass at high resolution, providing unprecedented insight into the mixed phase cloud (MPC) transition from rolls to cells. We study the interaction between large-scale forcing, surface fluxes, radiative transfer, and cloud processes in the formation and evolution of mesoscale organization and MPCs. As part of this effort, we utilize the Cloud Resolving Model Radar Simulator (CR-SIM) to compare WRF more directly to the measurements. Our CR-SIM analysis suggests that convective cell structures and properties are well modeled at the AMF1 site when using turbulence-resolving resolutions.
The spatial delineation of geosites: an approach for effective management and geoconservation
Authors: Ferrando Andrea , Faccini Francesco , Coratza Paola , Reynard Emmanuel
Published: March 2024

When doing geomorphosite inventories, one important issue concerns the spatial delineation of the sites themselves. Several authors have proposed classifications of geomorphosites depending on their size and degree of complexity of the processes involved. Depending on the geomorphological conditions of the studied area, the perimeter of a geomorphosite can include a single landform, a cluster of landforms that may be more or less interconnected, as well as large portions of landscape (geomorphological systems). However, these typologies, and the related spatial delineation, do not take into account the possible future evolution of landforms and more in general their management and their evolution. Indeed, in many cases, threats to the integrity of sites, be they natural or anthropogenic in origin, come from outside the perimeter of the site itself. Morphogenetic processes acting in a more or less extensive area around the geomorphosite influence its evolution and eventually its degradation. Therefore, in assessing the risk of degradation of geomorphosites and their management, one should analyze a wider area than the single perimeter, that is, the whole geomorphological system in which the site is located. In this research, the identification of a second perimeter for each geomorphosite, i.e., a "management perimeter", is proposed to be considered for the assessment of the degradation risk and geoconservation. The extent of the “management perimeter” depends on the characteristics and specificities of the geomorphosite. In some cases it may correspond with its own perimeter, in other cases it may encompass a very large area where processes influence the geomorphosite itself. The proposed approach is tested in two different areas: a mountain context – Val d'Hérens (Valais, Switzerland) – and a coastal context – Liguria (Italy). In conclusion, a typology of geomorphosites into categories for which the identification of the “management perimeter” is more or less homogeneous is proposed. This research highlights how the management and conservation of geosites should be approached with a systemic view, so as to understand how the main features of a geomorphosite interact with the active processes, natural and anthropogenic, acting in the surrounding area.
Statistics of Small-Scale Ionospheric Waves in European Mid-Latitudes Observed Using LOFAR
Authors: Boyde Ben , Wood Alan , Dorrian Gareth , de Gasperin Francesco , Sweijen Frits , Mevius Maaijke , Beser Kasia
Published: March 2024

The LOw Frequency ARray (LOFAR) is a radio telescope centred in the Netherlands. The observed impact of the ionosphere on signals from astronomical radio sources can be used to derive differential Total Electron Content (dTEC) between the lines of sight from different LOFAR stations. The dTEC derived in calibration has extremely high precision (~1 mTECu) and is available at high temporal (~4s) and spatial (baselines from ~100 m to ~100 km) resolutions. These measurements provide a new means of studying ionospheric disturbances in the mid-latitudes.A method for identifying wave signatures in the dTEC data has been developed and shown to be capable of identifying waves with amplitudes as low as a few mTECu (Boyde et al., 2023). This method has been used to analyse over 2,500 hours of observations made as part of an astronomical survey. The statistical characteristics of the identified waves and their dependence on time of day, season, and geomagnetic activity are discussed, such as variations in dominant propagation direction. These observations extend the range of ionospheric waves that can be identified to shorter wavelengths and lower amplitudes beyond what is currently detectable using GNSS derived TEC. This method complements established techniques for detecting ionospheric waves.Ben Boyde, Alan George Wood, Gareth Dorrian, et al. Wavelet Analysis of Differential TEC Measurements Obtained Using LOFAR, Radio Science (Under Review), 2023, doi: 10.22541/essoar.169754969.93126117/v
Support for the combined agricultural application of EO and non-EO data with the Danube Data Cube platform
Authors: Tolnai Márton
Published: March 2024

Earth Observation data is indispensable for agricultural monitoring and has a huge potential in managing operations at farming companies, accelerating strategy formulation processes at consultancy firms, and making risk assessment more robust at insurance companies. 
To realize these potentials and deliver the expected benefits to the agricultural sector, EO data-based services must be easy to understand for non-space actors, cost-efficient, and conform with the standard information services on a technical level. 
Furthermore, to deliver valuable services, such as crop growth modeling and yield forecasting, EO data must be combined with non-EO environmental data sets, such as meteorology, soil, and in-situ measurements from local sensor networks. 
Danube Data Cube is a regional data exploration platform that aims to support the agricultural sector with relevant information services, APIs, and applications for specific practical tasks in a cost-efficient and scalable way. Based on CDSE, the platform provides standardized access to EO and non-EO datasets through combined data cubes with high-level API availability and application hosting for 3rd party value adders. 
The platform aims to facilitate the creation of targeted software solutions dedicated to end users in the agricultural sector. 
This presentation provides insight into our technical stack, platform-, and business logic. Besides the general platform functionality, we also present two use cases of end-user software solutions built on the Danube Data Cube platform: 

Irrigation optimization
Strategy formulation for a growing season
Improving PSI Capabilities on Ground Deformation Monitoring for The Application of Geo-Energy Projects. 
Authors: Ramlie Maria Carmelia , Olea-Encina Paula , Crosetto Michele , Monserrat Oriol
Published: March 2024

PSI Technique remains a powerful remote sensing method in terms of ground deformation monitoring, which makes it useful for monitoring geo-energy projects such as geothermal and CO2 sequestration where movement is always detected. The monitoring is a crucial supporting component to ensure the smooth progress of geo-energy development. However, PSI Technique still faces some problems that affects the accuracy of the detection. This can be caused by data and related to the terrain of the study areas, such as vegetation, buildings, and the direction of the ground deformation. The goal is to counteract this is by combining multiple sensor images, both low resolution and high resolution. These can be obtained from the wide range of satellites available today such as Sentinel-1, TerraSAR, COSMO-SKYMED, and NISAR. This technique is supposed to increase the temporal sampling for a more comprehensive time series, redundancy to improve accuracy and robustness of PSI analysis, wider coverage by exploiting at each site the data that offers best performances. Aside from the expected improvement, some challenges in developing this technique will be presented. Most of the challenges are due to the difference in satellites’ characteristics, such as resolution, pixel spacing, wavelength, and geometry. The technique is planned to be applied on several study areas. The purpose of this is to study the effects of different terrain characteristics on the re-sampling process, tuning processes, and the result of the processing. One of the study areas will serve as the benchmark of the research.
Slab dynamics in the mantle: a back-to-basics approach
Authors: Plimmer Abigail , Davies Huw , Panton James
Published: March 2024

Subduction is one of the most fundamental processes on Earth, linking the lithosphere and mantle and is a key driving force in mantle circulation. Despite this, and the advancement of geophysical methods which allow us to better understand mantle dynamics, our understanding of slab behaviour is still limited. The Earth is a very complex system, and so conclusions regarding slab dynamics are also sensitive to the interplay between countless processes acting within the mantle. There is much to learn about slab sinking in the mantle from considering a single 'perfect' plate, such that the dynamics can be isolated from any pre-established or distal processes. We present a range of 3D spherical mantle circulation models which evolve from the initial condition, driven by a 'perfect' plate at the surface. Each of these plates comprises a rectangular geometry, bound by a subduction zone on one side, a spreading ridge on the opposite side, and two tranform faults on the adjacent edges. We vary the geometry of the plate, both in terms of the length of the subducting trench, and the distance from the trench to the ridge, and vary the plate velocity.We will report the slab behaviour in terms of plate geometry, mantle properties, and plate velocity, focussing on the evolution of downwellings, upwellings and other mantle structures in response to mantle circulation models driven solely by a single plate at the surface.
Quantifying cloud microphysical uncertainties in an extratropical cyclone’s ascending airstream using Lagrangian diagnostics
Authors: Oertel Annika , Miltenberger Annette K. , Grams Christian M. , Hoose Corinna
Published: March 2024

The characteristic large-scale and strongly precipitating cloud band in extratropical cyclones is associated with the so-called warm conveyor belt (WCB), which is a coherent cyclone-relative airstream that ascends cross-isentropically from the boundary layer into the upper troposphere. Cloud microphysical processes along this ascending airstream determine the total diabatic heating, cloud structure, and associated surface precipitation characteristics.We disentangle uncertainty related to the representation of cloud microphysical processes in the two-moment microphysics scheme of the ICOsahedral Nonhydrostatic (ICON) modeling framework in a convection-permitting simulation setup for an extratropical cyclone case study in the North Atlantic. To quantify uncertainty, we employ a perturbed parameter ensemble (PPE) approach, whereby five selected uncertain parameters in the cloud microphysics scheme and environmental conditions relevant for cloud formation are perturbed simultaneously and systematically. Specifically, cloud microphysical uncertainty is quantified along Lagrangian WCB trajectories which are calculated online during the ICON simulations from the resolved 3D wind fields at every model time step for each of the 70 PPE members. The Lagrangian perspective not only facilitates the characterisation of the airstream’s ascent behaviour but also provides detailed insight in cloud and precipitation formation along the ascent. The application of the Lagrangian diagnostics to all PPE members enables the quantification of dominant contributions of uncertainty from the perturbed parameters for WCB ascent characteristics, such as ascent timescales and tracks, as well as for precipitation formation along the ascent.For example, we show that the precipitation efficiency along the ascending airstream is most strongly influenced by cloud condensation nuclei (CCN) concentrations modifying the cloud droplet to rain drop conversion. Moreover, a trajectory-based airstream-relative composite analysis shows that increased CCN concentrations result in a downstream shift of the surface precipitation relative to the eastward propagating airstream as the precipitation efficiency is reduced. In addition, the Lagrangian diagnostics can illustrate the feedback between diabatic heating from cloud microphysical processes in the mixed-phase and local vertical velocity. In this contribution we present our analysis framework and show how the perturbed parameters influence various Lagrangian diagnostics for WCB ascent and associated cloud and precipitation formation.
Seamounts Generate Efficient Biological Carbon Pump Processes to Nourish the Twilight Ecosystem
Authors: Wang Xinyang
Published: March 2024

The vast and rugged seafloor, densely populated with unique topographic characteristics such as seamounts, serves as hotspots for ocean deep-sea biodiversity and fisheries resources. For oligotrophic regions covering more than a quarter of the global ocean, such unique topography regions are ecological oases within the oceanic desert. However, research on these ecological hotspots remains scarce, particularly in understanding the mechanisms behind the formation of these ecological oases. We selected a shallow seamount in a typical oligotrophic region as a case study and conducted comprehensive on-site physical, chemical, and biological observations, revealing its coupled temporal and spatial response characteristics. By comparing observations from multiple 24-hour time-series stations at different locations on the seamount, we uncovered the differential response characteristics between the upstream and downstream sides induced by the seamount topography. Based on this, we elucidated the efficient organic matter production and export processes on the seamount, attempting to propose a mechanism for the formation of seamount ecological oases.
Long term IMS infrasound measurements and seismo-acoustical analyses as a passive probe for climate change
Authors: Evers Läslo G. , Assink Jelle D.
Published: March 2024

The atmosphere is changing on a wide variety of timescales. The infrasound component of the International Monitoring System (IMS ) can sense such changes, each second over periods of tens of years. Such long term measurements of atmospheric variability enable the study of climate change. Infrasonic waves passively probe the entire atmosphere. The challenge is to unravel temperature variability (long term increases and decreases) from surface based recordings. As a reference, seismic signals are used which remain unchanged as a function of time. A so-called seismoacoustic analysis uses both seismic and infrasonic signals, where changes in the recordings can be attributed to changes in the medium. The latter being temperature changes in the troposphere and stratosphere.To illustrate the contribution of the IMS to climate studies, over 15 years of IMS seismic and infrasonic recordings will be shown. The seismoacoustic analysis performed with the recordings reveals long term changes in atmospheric temperature. Simultaneously a temperature increase in the troposphere and decrease in the stratosphere can be passively sensed.
AGEMERA AI: Innovative AI solution for responsible resource exploration
Authors: Stimac Tumara Barbara , Matselyukh Taras
Published: March 2024

In the context of the AGEMERA project (European Union's Horizon Europe research and innovation programme under grant agreement No 101058178), OPT/NET introduced the AGEMERA Platform as an extension to its flagship product, MONITORED AITM. AGEMERA's core objectives include unlocking the EU's resource potential, enhancing public awareness of critical raw materials, and fostering environmentally and socially responsible mineral exploration.OPT/NET solutions deliver exceptional user experience through an intuitive AI-driven interface, streamlining the complex processes of remote sensing data acquisition and data fusion to boost productivity by merging AI processing and automation with human problem-solving skills. The AI engine optimally harnesses heterogeneous Earth Observation data (predominantly  Copernicus Programme) and analysis-ready data from multiple heterogeneous and multimodal sources, promoting responsible mineral exploration and addressing environmental concerns, resulting in an interactive user-friendly web platform.The platform is structured around three main modules:OCLI 
Serving as the backend, OCLI manages data mining processes and automates functions, such as data acquisition, preprocessing, image processing, thorough workflows known as AI Knowledge Packs (AIKPs). OCLI collects relevant satellite data products, prepares analysis-ready data (ARD) cubes, and acts as the foundation for multi-source data fusion.AGEMERA Geo-Suite Graphical User Interface 
As the frontend module, this web-based platform offers a general data repository and visualization in Cloud Optimized data formats. Powered by OGC standards compliant web services, it enables interactive exploration of extensive datasets for the public and mine site operators and owners. The conversational AI agent assists in easy navigation through the extensive collection of the data and insights in the platform, while the data itself is secured with various authentication and authorization access levels.Data Repository
Comprised of bulk data warehouse enriched with INSPIRE nomenclature compliant metadata, the Data Repository employs Cloud Object Storage Service as the primary storage solution. This service provides web-based access to the object storage, ensuring efficient data access from any web browser.OPT/NET's AI platform, exemplified in the AGEMERA project, stands as a pioneering solution seamlessly integrating AI processing, heterogeneous data fusion, human problem-solving, and advanced data management for generation of impactful insights and responsible resource exploration.
Full-cycle greenhouse gas balance of a Sphagnum paludiculture site on formerbog grassland in Germany
Authors: Daun Caroline , Huth Vytas , Gaudig Greta , Günther Anke , Krebs Matthias , Jurasinski Gerald
Published: March 2024

The cultivation of peat mosses on rewetted peatlands (= Sphagnum paludiculture) is a promising alternative to drainage-based land use, as the production function is maintained while greenhouse gas (GHG) emissions are reduced. However, to date, GHG exchange studies that cover the entire production system and a complete production cycle are missing. Therefore, we combined data from the establishment phase (2011-2013) with data from the production phase (2017-2018) of a seven-year Sphagnum paludiculture in northwestern Germany including export by harvest. GHG exchange was recorded on all elements of the production system (Sphagnum production fields, ditches, causeways) with closed chamber measurements. Over the entire production cycle, Sphagnum production fields represented net GHG sinks of -3.2 ± 4.2 t ha-1 a-1 (in CO2-eq), while ditches and causeways were GHG sources of 13.8 ± 11.5 and 29.3 ± 9.8 t ha-1 a-1, respectively. Corrected for the percentage of area of each element of the production system and including partial harvest of peat moss (in dry matter) of ~13.8 ± 0.6 t ha-1, Sphagnum paludiculture was a net GHG source of 10.7 ± 4.6 t ha-1 a-1, reducing net GHG emissions by ~20 t ha-1 a-1 compared to grassland on drained organic soils. Per ton of dry biomass harvested, Sphagnum paludiculture emitted 9.9 ± 4.6 t CO2-eq. Because of their high area share, causeways contributed the most to net warming, suggesting a reduction in causeway area in future Sphagnum paludiculture. Therefore, a realistic future "best practice" approach features area percentages of 80% Sphagnum production fields, 5% ditches, 15% causeways, and a full biomass harvest, with the top 5 cm of harvested peat moss lawn used on-site for reseeding Sphagnum production fields. This approach reduces CO2 equivalent emissions from Sphagnum paludiculture to up to 4.3 ± 1.9 t ha-1 a-1 or 0.9 ± 2.1 t per ton of dry matter harvested.
Assessing ultrafine particle concentrations in the Rotterdam region using modelling and measurements
Authors: Denk Luka , Manders Astrid M.M. , Tokaya Janot , Visschedijk Antoon , Los Alexander
Published: March 2024

Population in urbanized areas is consistently exposed to elevated concentrations of ultrafine particles (UFP). Due to limited UFP measurement data, a modelling approach can help fill the gaps in both spatial and temporal coverage of the observation network. This study utilizes the LOTOS-EUROS model and measurements to characterize UFP concentrations within the urban area of Rotterdam, The Netherlands. Rotterdam is a particularly interesting location as it contains a variety of UFP sources (shipping, industry, traffic, airport).The LOTOS-EUROS model is extended with the SALSA2 module for particle dynamics. Currently nucleation is not taken into account in LOTOS-EUROS and measurements are used to provide background conditions for the 1x1 km2 resolution model domain. Within the domain, a new UFP emission inventory for this area is used. The model results are compared with measurements obtained from a 1-month summer campaign from the Rijnmond Central Environmental Management Service (DCMR) and from the Ruisdael Observatory. Measurement locations include Veldkersweg (urban background with influence of road and airport) and Nieuwe Maas (urban background, influenced by shipping) and the rural Cabauw observatory.We will provide a joint analysis of measurements and model results that provides valuable insight in the behaviour of UFP in the Rotterdam region. As expected, both urban locations, Veldkersweg and Nieuwe Maas, exhibit consistently higher PNC compared to the more remote Cabauw observatory. Model results clearly show the large contributions from shipping in the area. Comparison with observations reveal that background values are modelled reasonably well but that the model can currently not represent the higher values of two urban observation stations measuring UFP. Further model development is needed to include nucleation. In addition, more research is needed to quantify the competing effects of coagulation and deposition close to the source, which relates to the questions how emissions as reported in the emission inventory can be used in a model like LOTOS-EUROS, where instant dilution applies. 
Global Ocean spectral slope rupture evidenced by SWOT 21-day orbit observations
Authors: Vergara Oscar , Morrow Rosemary , Chevrier Robin , Dibarboure Gérald , Picot Nicolas
Published: March 2024

Embarking both the revolutionary KaRIn 2D imaging SAR interferometer and a Jason-class nadir altimeter, the SWOT mission provides sub-50 km wavelength ocean sea surface height observations. With its unprecedented spatial resolution, coupled with an extremely low noise, the SWOT KaRIn observations will allow us to characterize ocean dynamics for wavelengths well below the capabilities of conventional nadir altimetry.  

Along-track Sea Surface Height (SSH) observations (1 Hz) have been recently used to tease out the spectral characteristics of oceanic variability in the meso- to sub-mesoscale wavelength range (wavelength < 100 km). Conventional altimetry reveals a regime shift in many tropical and subtropical regions, where a quasi-geostrophic energy cascade changes to a flatter, non-geostrophic dynamical regime at smaller wavelengths. Yet at higher latitudes, with smaller Rossby radius, this regime shift was not apparent, hidden by the higher conventional altimetry noise at smaller wavelengths. In the present study, we take advantage of the multi-instrumental characteristics of the SWOT mission, embarking a conventional nadir altimeter in addition to KarIn with its improved signal-to-noise ratio, to characterize the spectral slope rupture at global scale. We use SWOT data available during the first months of the mission’s 21-day repeat orbit and compare these results against latest model and in situ estimates.  

This wavelength scale, where the geostrophic energy cascade becomes dominated by non-geostrophic dynamics (e.g. internal gravity waves including internal tides) is important for using and interpreting SSH-derived geostrophic current data, and to quantify the regions and seasons where the geostrophic assumption breaks down. Our results could therefore be used as an indicator for this scenario, as more high-resolution SWOT data becomes available and is integrated into multi-mission global SSH products and their derived geostrophic currents.
Coupling Timing and Tempo of Deccan Volcanism with the KPg Extinction: Evidence from Mercury and Tellurium Anomalies
Authors: Adatte Thierry , Regelous Marcel , Baumann Nils , Hassan Khozyem Hassan , Spangenberg Jorge E. , Keller Gerta , Karabeyoglu Uygar , Schoene Blair , Khadri Syed
Published: March 2024

Mercury (Hg) and more recently tellurium (Te) are indicator of large-scale volcanism in marine sediments and provide valuable insights into relative timing between biological and environmental changes, mass extinctions and delayed recovery. Several studies evaluated the relationship between Hg anomalies in sediments and LIP activity across mass extinction horizons. The bulk (80%) of Deccan Trap eruptions occurred over a relatively short time interval in magnetic polarity C29r. U-Pb zircon geochronology reveals the onset of this main eruption phase 350 ky before the Cretaceous-Tertiary (KT) mass extinction. Maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction, suggesting a cause-and-effect relationship. We present a comprehensive high-resolution analysis of Deccan Traps Hg-Te loading, climate change and end-Cretaceous (KPB) mass extinction from a transect, which includes 30 sections deposited in both shallow and deep environments located in France, Spain, Italia, Denmark, Israel and Tunisia. In all sections, our findings indicate that Hg concentrations are more than 2 orders of magnitude greater during the final 100ky of the Maastrichtian up to the early Danian P1a zone (first 380 Ky of the Paleocene). Notably, Hg anomalies generally show no correlation with clay or total organic carbon contents, suggesting that the mercury enrichments resulted from higher input of atmospheric Hg species into the marine realm, rather than being driven by organic matter scavenging and/or increased run-off. Significant and coeval Hg enrichments are observed in multiples basins characterized by proximal and distal, as well as shallow and deep-water settings, supporting a direct fallout from volcanic aerosols. Hg enrichments are not observed in the Indian redboles, confirming that it is not a proximal proxy for volcanism. But significant Hg anomalies have been found in more distal intertrapeans sediments at Anjar (Gujarat), Daiwal and Podgavan (SW Nagpur, Maharashtra). Significant Hg anomalies are also found in the more distal Megalaya section. Hg isotope data from Bidart confirm a direct Hg fallout from volcanic aerosols. Furthermore, Te/Th ratios measured in the Goniuk (Turkey), Elles (Tunisia), Gubbio (Italy) and Wadi Nukhul (Egypt) sections show the same trend as Hg/TOC and are consistent with a volcanic origin, albeit a minor extraterrestrial contribution of Hg at the boundary cannot be excluded. Hg and Te maximum loadings coincide with time of maximum Deccan emission rates and volumes determined by zircon dating. Hg and Te concentrations within sediments in conjunction with Te/Th and Hg/TOC ratios are therefore robust and useful proxies to trace intensity of volcanism.
Mercury Speciation in Soils and Its Influence on Bioaccumulation in Crops at a 33-Year-Old Solid Waste Dumping Site
Authors: Dey Arup , Chakraborty Parthasarathi , Padalkar Prasad
Published: March 2024

Mercury (Hg) pollution garnered global attention after the Minamata disaster. The complex biogeochemical processes governing soil Hg distribution, speciation, and its accumulation in crops have remained elusive. This study investigates the soil Hg distribution, speciation, and bioaccumulation in crops at Dhapa, a 33-year-old solid waste dumping station of the Kolkata Municipal Corporation. Vegetable cultivation in this 35-hectare area rely on industrial wastewater of the city for irrigation, and these sewage-irrigated vegetables find their way into markets across the Kolkata suburbs. Whole plant of vegetable crops and paired soil samples were collected from 92 locations in the study area. The findings unveiled a wide range of soil total Hg (THg) concentrations, spanning from 48 ± 2.4 to 8108 ± 405.4 µg/kg, with an average of 1697 µg/kg. 45% of the total samples surpassed the Maximum Permissible Concentration of Hg in agricultural soil (1500 µg/kg), and 91% exceeded the background concentration of world soils (400 µg/kg), indicating significant ecological risks. The chemical speciation study revealed that soil organic matter (SOM) was the dominant hosting phase for Hg in the studied soil. According to relative abundance, the different species could be arranged as follows: Hg bound to SOM> elemental Hg > Hg bound to sulphides > Hg bound to reducing binding phase > residual fraction of Hg. High elemental Hg contents (average: 21.86 ± 1.1% of THg) underscore prominent Hg (II) reduction in the soils. Among edible parts of the vegetables examined, the highest accumulation was observed in leafy vegetables. The edible parts, as per the bioaccumulation factor (Hg concentration in edible part / soil THg), could be sorted as Cauliflower < Bottlegourd < Malabar spinach (Poi) < Ipomea< Brinjal < Radish (root) < Amaranthus< Spinach. According to Polish, Serbian, and Chinese regulations, all vegetable crops (besides Cauliflower) exceeded the maximum tolerable limit (300 µg/kg). SOM-bound was identified as the chemical form of Hg primarily responsible for its root uptake. Interestingly, shoot Hg contents were significantly correlated to soil elemental Hg contents, which implies that soil Hg evasion contributes to Hg uptake in plant shoots. The findings of this study suggest that high organic matter input in polluted soils could enhance the phytoaccumulation of Hg. The outcomes of this study will contribute to assisting policymakers in minimizing human exposure to mercury (Hg) by providing comprehensive guidelines on vegetable intake from this area. Additionally, the study's results will be valuable for farmers, helping them select crops that demonstrate low uptake of mercury.
Draining or Refreezing? Investigating Meltwater Lake Evolution through Deep Learning
Authors: de Roda Husman Sophie , Lhermitte Stef , Psomouli Theofani , van Noord Meike , Bambler Jonathan , Zhu Xiao Xiang , Wouters Bert
Published: March 2024

Antarctic ice shelves are becoming more vulnerable as a warming atmosphere leads to surface melting and the formation of meltwater lakes. Some meltwater lakes in Antarctica refreeze, but others drain into ice fractures, potentially destabilizing ice shelves and thereby contributing to rising sea levels. Conventional monitoring, using optical satellites, tracks lake changes during a melt season if data is accessible. However, cloud cover in Antarctica limits the use of optical imagery, creating a shortage of useful images and making it challenging to track lake progression. Unlike optical imagery, radar data from sources like Sentinel-1 offers frequent coverage of Antarctic ice shelves, because Sentinel-1 works independently from sun illumination and weather conditions. However, interpreting it is complex due to factors such as looking geometry, polarization, and speckle noise. By training our model on optical imagery from both refreezing and draining lakes—serving as ground truth—we applied a spatiotemporal deep learning technique to extract meaningful information from the Sentinel-1 images. Our results show that the majority of Antarctic meltwater lakes underwent refreezing from 2017 to 2023. However, a significant number of draining lakes were also identified, many of which had not been previously discovered through optical imagery. As the vulnerability of Antarctica's ice shelves intensifies, Sentinel-1's ability to provide insights into surface lake dynamics presents a promising avenue for research, enhancing our understanding of these crucial systems in the context of climate change and sea level rise.
Analyzing Hydro-Meteorological Droughts Using SSPs Scenarios (Case Study: Kasungu, Malawi)
Authors: Mirzadeh Seyed Jafar , Richard Chikabvumbwa Sylvester
Published: March 2024

Due to the impacts of climate change and global warming, Malawi has experienced severe droughts in recent years. Hydro-meteorological drought prediction has been underexplored in Malawi and Southern Africa. This study investigates key CMIP6 climate scenarios to characterize hydro-meteorological droughts in the Kasungu Agricultural Development Division (ADD). The objective is to assess and predict hydro-meteorological droughts in Central Malawi using a multi-model ensemble from eight CMIP6 models across four SSPs (Shared Socioeconomic Pathways) scenarios. The research emphasizes the importance of understanding drought evolution under future climate scenarios for effective water resource management, enhanced drought preparedness, and comprehensive adaptation plans. The study calculates the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and Palmer Drought Severity Index (PDSI). Results suggest an increased likelihood of moderate and mild droughts in the mid-term of the 2020–2029 period in the region. All three meteorological droughts indicate a significant rise in dry conditions. Under SSP1-2.6 and SSP5-8.5, ADD rainfall is projected to decrease by 1.8% and 4.3%, respectively, with more extremely dry conditions under SSP5-8.5. Dry regime frequency is expected to rise for all stations under SSP5-8.5. The findings reveal robust changes in drought characteristics under higher emissions scenarios in Kasungu ADD. Agriculture experts, policymakers, and engineers must comprehend historical and future drought patterns for effective drought mitigation in the region. Similar studies using other CMIP6 models can be conducted in ADD to compare results, ensuring a comprehensive understanding of drought dynamics.
Interannual variations in Δ(17O) of atmospheric CO2 suggest a strong link with stratospheric input
Authors: Steur Pharahilda , Scheeren Hubertus A. , Koren Gerbrand , Adnew Getachew A. , Peters Wouter , Meijer Harro A. J.
Published: March 2024

We present multiple year records of the triple oxygen isotope signature Δ(17O) of atmospheric CO2 conducted with laser absorption spectroscopy, from Lutjewad in the Netherlands (53° 24’N, 6° 21’E) and Mace Head in Ireland (53° 20’ N, 9° 54’ W). Measurements were done on flask samples covering the period 2017-2022. The average uncertainty of 0.07 ‰ is about 3 times smaller than the total observed variability. A positive Δ(17O) originates from intrusions of stratospheric CO2, whereas values close to zero result from equilibration of CO2 and water, predominantly happening inside plants due to enhanced dissolution in the presence of carbonic anhydrase. A biosphere driven seasonal signal is, however, not observed in the records. Both records show significant interannual variability, of up to 0.3 ‰. The total range covered by smoothed monthly averages from the Lutjewad record is -0.065 to 0.046 ‰, which is significantly higher than the range of -0.009 to 0.036 ‰ that was simulated with a 3-D transport model. One of the major model uncertainties is the representation of the stratospheric influx of Δ(17O). We modified the model using the 100 hPa 60-90° North monthly mean temperature anomaly as a proxy to scale stratospheric downwelling. This results in a strong improvement of the correlation coefficient of the simulated and the observed year-to-year Δ(17O) variations at Lutjewad over 2019 and 2022 from 0.37 to 0.81 (N=22). To infer terrestrial carbon fluxes, the contribution of the stratosphere to the observed signal should therefore be considered. In fact, as the Δ(17O) of atmospheric CO2  seems to be dominated by stratospheric influx, it might be used as a tracer for stratosphere-troposphere exchange. To further study the potential of Δ(17O) of atmospheric CO2 as a tracer for stratosphere-troposphere exchange at Lutjewad, we installed a laser absorption spectrometer at the measurement station for in-situ measurements. At Lutjewad numerous other atmospheric species are monitored, such as N2O, Rn and 14C. This will enable us to deepen our knowledge on the mechanisms that drive the interannual variability of Δ(17O) of atmospheric CO2  that we observe at Lutjewad.

 

 
Lead in particulate matter source apportioning by HR-MC-ICPMS stable isotope ratio measurements
Authors: Caso Giuseppe , Di Rosa Maria , Di Rosa Salvatore , Rubino Mauro , Marzaioli Fabio
Published: March 2024

During the last decades great attention was paid to Particulate Matter (PM) due to the correlation between fine PM exposure and adverse health effects.  Among the airborne pollutants, Lead (Pb) is one of the most widespread and toxicologically important. Metallic Pb and inorganic Pb compounds are classified as possible carcinogenic for humans. Pb can bioaccumulate in the human body system, causing damage to human nervous system, cardiovascular diseases, reproductive impairments, and catalyzing cells oxidative stress.  In Italy, Legislative Decree no. 155 of 13/08/2010 (implementation of European Directive 2008/50/EC) defines the atmospheric PM10, PM2.5 and airborne pollutants threshold concentration values. These threshold values are applied for anthropogenic particulates, so, the Pb source apportioning in PM can offer the key to manage the problem.   Pb has four stable isotopes, i.e. 204Pb, 206Pb, 207Pb, and 208Pb. The isotopic ratios of Pb act as “fingerprint” that allows to identify the PM emission sources in the environment (crustal, vehicular traffic, municipal solid waste incinerator, etc …).  The PM 2.5 and PM10 sampling will be carried out by ARPAC monitoring network, using high-volume samplers placed in Campania (Italy) environmental interest points (urban centers, busy roads…). The sampling flow is 2.36 m3/h, single sampling time is 24 hours and the use of quartz fiber filters Ø = 47mm is provided (according to the technical standard UNI EN 12341:2014).  Precise and accurate measurement of Pb and relative isotope ratios requires a multi-step process for analysis of solid samples:Microwave-assisted treatment of filters with strong acid to solubilize all the metallic species (EPA 3051 A 2007);
A First qualitative and quantitative measurement by Inducted Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to estimate the total Pb concentration (moreover, the quali-quantitative determination of other metals is an important information for environmental purposes);
Lead Extraction and purification from matrix and interfering elements by ionic resins in ISO 4 clean room;
Mass spectrometry measurement for lead isotope analysis by High Resolution Multi-Collector Inducted Coupled Plasma Mass Spectrometry (HR-MC-ICPMS).
Improvement of data interpretation accuracy comparing experimental data to isotopic lead ratio values in research databases (i.e. IBERLID: lead isotope database and tool for metal provenance and ore deposits research).
  However, the identification of anthropogenic Pb sources enables to establish the origin of a portion of collected PM. So, when an overcoming of PM threshold concentration is observed, thanks to the isotopic analysis information, competent authorities can act in an efficient and successful way.
Sensitivity of different variants of GENESIS orbit to global geodetic parameters
Authors: Kur Tomasz , Sośnica Krzysztof
Published: March 2024

The GENESIS mission plays a pivotal role in the FutureNAV program envisioned by the European Space Agency. This groundbreaking venture aims to co-locate four space geodetic techniques on a single platform in space. One of the primary mission objectives is accurately determining geodetic parameters, including geocenter motion, low-degree gravity field, Earth rotation parameters, and the positions of ground stations in tracking networks. Although preliminary satellite inclination and altitude were provided, there is untapped potential for studying ways to enhance the efficiency of incorporating GENESIS into geodetic products.This research focuses on the preliminary optimization of GENESIS orbital parameters – semi-major axis, inclination, and eccentricity- to assess the benefits arising from diverse observation geometries on geodetic products. The analysis is based on simulations of different variants of GENESIS orbital parameters tracked by a network of 20 satellite laser ranging (SLR) stations. We provide GENESIS-only solutions as well as the combined solution with a selected subset of geodetic satellites that are used today or in the future for the realization of the terrestrial reference frames: LAGEOS-1, LAGEOS-2, LARES-1, and LARES-2. GENESIS will be equipped with two GNSS receivers contributing to high-accuracy orbit determination, serving as a priori parameters for SLR-based solutions. Therefore, we check the GENESIS sensitivity to global geodetic parameters, assuming that the precise orbits are not derived from SLR but can be well-defined from other techniques.We study the impact of different GENESIS orbits on the gravity potential parameters, especially the zonal terms, Earth rotation parameters, and geocenter coordinates. Our findings underscore that, through meticulous processing, GENESIS has the potential to significantly contribute to achieving the goals of the Global Geodetic Observing System (GGOS), particularly in terms of refining the Z component of the geocenter coordinates.
Environmental and physical factors controlling the distribution of 137Cs in lake sediments in the Southern Hemisphere: a meta-analysis
Authors: Guillevic Floriane , Evrard Olivier , Sabatier Pierre , Foucher Anthony , Dicen Gerald , Alewell Christine
Published: March 2024

For decades the artificial radionuclide 137Cs has been used as an independent time marker to ascertain the 210Pb chronology to date recent sediments from the Anthropocene period (