bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of GNSS-based Integrated Water Vapor for the Swabian MOSES 2023 field campaign
Authors: Zus Florian , Oertel Annika , Muraleedharan Thundathil Rohith , Dick Galina , Knippertz Peter , Wickert Jens
Published: March 2024

The Swabian MOSES (Modular Observation Solutions for Earth Systems) field campaign was conducted between June and September 2023 in the southeastern Black Forest, the Neckar Valley and the Swabian Alb in southwestern Germany. It focused on hydro-meteorological extreme events, including the initiation and intensification of convective events which are accompanied by heavy rain and can lead to local flooding. As a part of the observing system the GFZ installed eight additional GNSS stations in the region of interest and operated them in near real time during the measurement campaign. The precise point positioning technique was utilized to provide Integrated Water Vapor (IWV) estimates with a temporal resolution of 15 min. In this contribution we provide a first comparison of these IWV estimates with those derived from atmospheric (re-) analysis datasets. We utilize the atmospheric reanalysis ERA5 (horizontal resolution 31 km) and the operational analysis ICON-D2 (horizontal resolution 2 km) provided by the German Weather Service. Ground-based GNSS data are not assimilated into ERA5 and ICON-D2. In general, we find good agreement between GNSS and (re-)analysis estimates: the root mean square error is 1-2 kg/m2. Our goal is to better understand the remaining station specific systematic and random deviations. For example, for all stations, the random deviations are smaller for the high compared to the low resolution model data. We attribute this to smaller representative errors and smaller forward model (interpolation) errors. However, for the systematic deviations the result is not too obvious. Comparisons with measurements from instruments which are collocated with the GNSS stations are envisaged to better understand the issue.  
Advancing Irrigation Strategies: Synergistic Modeling of Soil Moisture Using Cosmic-Ray Neutron Sensing, Hydrus-1D, and Machine Learning
Authors: Straface Salvatore , Brunetti Guglielmo Federico Antonio , Scozzari Andrea
Published: March 2024

Innovative monitoring techniques today facilitate advanced and reliable measurements in the vadose zone. This, coupled with the predictive capabilities of machine learning, has an ever-growing impact on the management of agricultural and irrigation practices. The vadose zone, particularly the root zone, plays a pivotal role in hydrological processes by regulating water and energy fluxes across the soil surface. Additionally, it influences nutrient transport, groundwater recharge, groundwater pollution, microbial activity, and plant physiology, as it links the atmosphere, soil, and groundwater. Among various monitoring techniques, Cosmic-Ray Neutron Sensing (CRNS) stands out as a ground-based remote sensing technique capable of measuring soil moisture within the root zone at relevant scales (up to 240 m) with a high level of reliability. It is based on nuclear interactions between incoming cosmic rays and elements in the Earth’s atmosphere, such as hydrogen. By employing the Hydrus-1D Cosmic module, effective soil moisture values can be derived based on the neutron intensity detected by Cosmic-Ray Neutron Probes (CRNPs). On the other hand, machine learning methods and neural networks (NN) hold enormous potential despite inherent limitations, notably the requirement for extensive datasets and their lack of a physical foundation in reproducing soil processes. In this study, we propose a synergistic approach to overcome these limitations. The physically-based Hydrus-1D model was utilized to train a single-layer NN for the direct prediction of soil moisture and irrigation water demand, relying exclusively on atmospheric forcings (temperature and precipitation) as input. In a proof-of-concept aimed at assessing the validity and robustness of our approach, a time series of synthetic data replicating soil characteristics, atmospheric forcings, and field measurements conducted through CRNPs was generated. These data were employed in the Hydrus-1D Cosmic module to calibrate a physically-based model, facilitating the generation of a continuous and extensive spatiotemporal soil moisture output dataset for the simulated synthetic field. The single-layer NN, trained with this synthetic soil moisture and atmospheric forcing data, demonstrated the potential to accurately predict soil moisture and irrigation needs of the terrain straightforwardly, using only atmospheric variables as input. The proposed synergistic approach has exhibited significant potential, and future developments in this research will involve the incorporation of real data.
Potential environmental impacts of natural and mining related dust in Greenland and Svalbard
Authors: Søndergaard Jens , Frigaard Rasmussen Christian , Hvidtfeldt Christiansen Hanne , Juncher Jørgensen Christian
Published: March 2024

Dispersion and deposition of mineral dust from natural or anthropogenic sources such as proglacial rivers, mines and haul roads can have both positive and negative effects on the environment, depending on the geochemical and mineralogical composition of the dust. Some elements in dust may act as nutrients for, for example, plants, lichens and soil communities, while other elements may act as pollutants with negative impacts on growth or reproduction or cause diseases in animals and plants.To support the sustainable development of environmentally safe mining in sensitive Arctic land areas and reduce airborne environmental pollution, an improved understanding of processes leading to the dispersion of mineral dust in a changing Arctic is needed. This involves improved methods for monitoring dust emissions and dust deposition in a cold environment as well as analytical tools and methods to source trace and differentiate between natural and mining related dust. Accurate identification of individual dust sources subsequently makes it possible to mitigate emissions and target the regulation of mining activities towards these sources.In this study, we present preliminary results from two new arctic dust monitoring stations in West Greenland and Svalbard. In Kangerlussuaq, West Greenland, mineral dust has been collected using a wide array of passive and active dust samplers, including a continuously operated high volume dust sampler at a weekly sampling frequency over 2022/2023. In Svalbard, mineral dust has been collected in Adventdalen using passive dust collectors in a transect along the haul road to the active coal mines. Samples have been collected on a weekly sampling frequency in the period September to November 2023 to investigate the temporal and spatial variations in dust deposition rates, as well as the impact of haul road traffic relative to the natural dust emissions and depositions.
Simulating UV-VIS Spectra for Polysulfur Species in the Venusian Atmosphere
Authors: Skog Robert , Frandsen Benjamin , Kurtén Theo
Published: March 2024

The Venusian atmosphere has everything to be an exciting natural sulfur laboratory. In addition to relatively high concentrations of sulfur dioxide, suitable conditions in the atmosphere make both thermo- and photochemical reactions possible, allowing for complex chemical reactions and the formation of new sulfur containing compounds. These compounds could explain or contribute to the enigmatic 320-400 nm absorption feature in the atmosphere. One of the proposed absorbers is polysulfur compounds. While some experimentally obtained UV-VIS spectra have been published, studying the different polysulfur species individually is extremely difficult due to the reactive nature of sulfur. In this work UV-VIS spectra for polysulfur species S2 to S8 were simulated using the nuclear ensemble approach to determine if they fit the absorption profile of the unknown absorber.Geometries were optimized at the ωB97X-D/aug-cc-pV(T+d)Z level of theory, with the S2, S3, and S4 structures also being optimized at the CCSD(T)/aug-cc-pV(T+d)Z level of theory. For the lowest energy isomers UV-VIS spectra were simulated using a nuclear ensemble of 2000 geometries, with vertical excitations calculated at the EOM-CCSD/def2-TZVPD or the ωB97X-D/def2-TZVPD levels of theory.The simulated UV-VIS spectra for the smaller species were in quite good agreement with experimental results. Two different molecules were identified with substantial absorption cross sections in the range of the unknown absorber: The open chain isomer of S3, and the trigonal isomer of S4 However, the mixing ratios of these species in the Venusian atmosphere are also needed to make a more conclusive statement. Other polysulfur compounds have insignificant absorption cross sections in the 320-400 nm range and can therefore be excluded.The calculated absorption cross sections can be used to calculate photolysis rates, which can be straight away added to atmospheric models of Venus. In addition, this work will help future space missions to Venus, for example by focusing their search for the unknown absorber.
A 60-cm Aerial Photography-based Water Body Mapping: Application to the Tama and Tsurumi Rivers in Japan
Authors: Watanabe Megumi , Yamazaki Dai
Published: March 2024

The current global water body maps offer an approximate resolution of 30 meters, contingent on available remote sensing data. However, to address the needs of advanced applications like global carbon cycle analysis and real-time flood predictions, a water body map with higher spatial resolution becomes imperative, especially for resolving smaller rivers. Traditional water extraction methods rely on water indexes that combine visible and infrared spectra. State-of-the-art remote sensing data, including aerial photography with spatial resolutions in the order of a few meters, often includes only the visible spectrum.In response to this challenge, we have developed a water extraction method at an impressive 60cm resolution utilizing Bayesian inference based solely on the visible spectrum from aerial photography, without using the infrared spectrum. To enhance our methodology, we integrated references of water existence from a Landsat-based dataset called G1WBM and Open Street Map (OSM), along with a hydrography dataset (J-FlwDir) presumed to be linked to water bodies.Our method successfully detected the main streams of the Tsurumi River and Tama River in Japan, including their previously unrecognized tributaries in the Landsat-based dataset. Notably, this study identified rivers with a width exceeding 10 meters. Furthermore, it contributed valuable area information for 37% of small rivers represented as "line" features in the OSM.These findings underscore the effectiveness of our Bayesian water detection approach, which leverages hydrography data and existing water body maps to improve the spatial resolution of large-scale water mapping significantly. Notably, this improvement is achieved using remote sensing data that lacks infrared spectra, showcasing the potential of our method in advancing the accuracy and precision of global water mapping efforts.
Assessing the impact of PM2.5 constituents in its overall toxicity in the urban region of Indo-Gangetic Plain 
Authors: Gupta Aman Deep , Gupta Tarun , Kumar Piyush , Misra Santosh
Published: March 2024

A detailed physio-chemical investigation of ambient PM2.5 constituents was conducted in order to identify the factors affecting its toxicological endpoints. The PM chemical components for various inorganic ions (SO42-, NO3-, NH4+, etc.), PAHs, water-soluble organic carbon (WSOC), water-soluble nitrogen (WSN), elemental and organic carbon (EC/OC) were analysed. The indicators mentioned above were assessed using ambient PM2.5 samples (n=30) collected from October to December 2021, over urban Kanpur region in the Indo-Gangetic Plain. To assess the toxicity of PM, cell viability assays were conducted on three distinct cell lines, namely NIH-3T3, B16-F0, and A549. It was found that PM chemical composition was major determinant in toxicity assessment rather than its mass concentration. PM2.5 samples containing greater amounts of OC and high-molecular-weight PAHs (4-6 rings) exhibited a more pronounced toxicity. Elevated concentrations of SO42- and NO3- were concurrent with these samples. The observed association between OC, SO42- and NO3- with cell toxicity suggests that chemical processing has the potential to increase the toxicity of PM2.5 particles. This was further validated by analysing the light absorption spectra of PM2.5 samples (350–500 nm), which revealed that samples with reduced cell viability exhibited more absorption in the spectra. Further, the spectrum analysis of higher toxicity samples indicated the possible presence of nitroaromatic and HULIS type chromophores causing toxicity in PM2.5. The other PM components, particularly EC, exhibited no association with any of the PM2.5 components which may be due to its inert nature. Therefore, EC and low-molecular-weight PAHs (2–3 rings) had the least impact on PM2.5 toxicity. This study revealed that the primary factors contributing to the toxicity of PM2.5 are the existence of organic molecules and their subsequent secondary transformations in the presence of SO42-, NH4+,and NO3-. Further, the study improves our understanding regarding the toxicity profiling of particulate matter, which may help in policy formulation to mitigate its impact.
Synergistic and unified retrieval of clouds, aerosols and precipitation from EarthCARE and the A-Train: the ACM-CAP and CCM-CAP products
Authors: Mason Shannon , Hogan Robin , Bozzo Alessio , Courtier Ben
Published: March 2024

EarthCARE will continue the record of spaceborne radar, lidar, and radiometric measurements that was begun in 2006 by CloudSat, CALIPSO, MODIS and CERES within the A-Train of satellites. EarthCARE’s multispectral imager (MSI), three-view broadband radiometer (BBR), Doppler-capable cloud profiling radar (CPR) and high-spectral resolution atmospheric lidar (ATLID) provide some advances over the instruments within the A-Train, and the single platform will improve the coregistration of synergistic measurements. Ultimately, the greatest novelty of the EarthCARE mission may arise from its highly coordinated L2 production models, which cover products ranging from single-instrument detection, target classification, and retrieval products, to synergistic retrievals, radiative transfer modelling, and finally top-of-atmosphere radiative closure assessment. Central to the ESA L2 production model is the synergistic (ATLID-CPR-MSI) “best estimate” retrieval of all clouds, aerosols and precipitation in the atmosphere, called ACM-CAP.ACM-CAP is based on the CAPTIVATE optimal estimation retrieval algorithm, which includes sophisticated and efficient representations of hydrometeor fallspeeds to constrain ice particle density and raindrop size, ice particle scattering properties, radar and lidar multiple scattering, passive solar, thermal and microwave radiances, and the HETEAC model for aerosol properties. To test our retrieval and enhance scientific continuity between EarthCARE and the A-Train, we have developed an equivalent CloudSat-CALIPSO-MODIS retrieval product, called CCM-CAP, based on the same retrieval algorithm. In this talk we provide an overview of the ACM-CAP product, its capabilities and its place within the EarthCARE ESA production model. Using CCM-CAP, we present case studies and evaluation of the retrieved cloud and precipitation properties, and discuss how the challenges for unified retrievals in complex and layered scenes will inform the regimes of interest for validation and evaluation once EarthCARE data are available.
Ab initio modelling of magnetite surfaces for radionuclide retention
Authors: Katheras Anita S. , Karalis Konstantinos , Krack Matthias , Scheinost Andreas C. , Churakov Sergey V.
Published: March 2024

In many European countries (e.g., France, Switzerland), thick steel casks are foreseen for the containment of high-level radioactive waste in deep geological repositories. In contact with pore-water, steel corrodes forming mixed iron oxides, mainly magnetite (Fe3O4). After tens of thousands of years, the casks may breach allowing for leaching of the radionuclides (e.g., Tc and Pu) into pore-water. The radionuclides can be retarded by corrosion products either by adsorption or via structural incorporation [1,2]. The molecular scale mechanisms of these phenomena are investigated by ab initio simulations and X-ray absorption spectroscopy (XAS).The dominant low-index surfaces of magnetite particles and their termination at the relevant conditions were identified based on Kohn-Sham density functional theory (DFT), using the open-source CP2K code [3]. The DFT+U method was employed for the strongly correlated 3d and 5f electrons of Fe and Pu, respectively. After benchmarking the model setup, the surface energies of the (111) facet with different surface terminations and water coverage were analyzed as a function of redox conditions and pH. The Eh and pH predominance diagram could be predicted for the most stable surfaces under real repository conditions [4]. Further, we confirmed these findings for nanocrystals with approximately 2 nm size. Subsequently, ab initio molecular dynamics (MD) were applied to simulate sorption structures of radionuclides on the expected magnetite (111) surfaces based on experimental findings [2,5].[1] R. Kirsch et al. Oxidation State and Local Structure of Plutonium Reacted with Magnetite, Mackinawite, and Chukanovite. Environmental Science & Technology, 2011, 45(17), 7267.[2] E. Yalçintaş et al. Systematic XAS study on the reduction and uptake of Tc by magnetite and mackinawite. Dalton Transactions, 2016, 45(44), 17874.[3] T. D. Kühne et al. CP2K: An Electronic Structure and Molecular Dynamics Software Package - Quickstep: Efficient and Accurate Electronic Structure Calculations. The Journal of Chemical Physics, 2020, 152(19), 194103.[4] A.S. Katheras et al. Stability and Speciation of Hydrated Magnetite {111} Surfaces from Ab Initio Simulations with Relevance for Geochemical Redox Processes. Environmental Science & Technology, 2024, 58(1), 935.[5] T. Dumas et al. Plutonium Retention Mechanisms by Magnetite under Anoxic Conditions: Entrapment versus Sorption. ACS Earth & Space Chemistry, 2019, 3(10), 2197.
Space-based sub-terahertz Inverse Synthetic Aperture Radar (ISAR) image formation and orbital assessment for monitoring of geostationary assets
Authors: Jones Gruffudd , Coe Morgan , Alconcel Leah-Nani , Gashinova Marina , Cherniakov Mikhail
Published: March 2024

The Pervasive Sensing group at the University of Birmingham is exploring in-orbit conditional monitoring of satellites using inverse synthetic aperture radar (ISAR) as a technique for dedicated observation of high-value space-based assets. In this work, the feasibility of geostationary orbit (GEO) observation by optimising monitoring satellite orbital parameters for sub-THz ISAR data acquisition has been assessed. A proprietary propagation simulator, Gofod, has been used to devise the scenarios for which launch conditions, stability, periodicity and time of dwell on the target will deliver the best observation of key observed satellite features. Simulation results have been validated with commercial software.
Assessing stream water scarcity and groundwater roles under global change in a Mediterranean watershed: the Onyar River basin (NE Catalonia, Spain)
Authors: Cordoba Ariza Paula Gabriela , Batalla Ramon J. , Sabater Sergi , Mas-Pla Josep
Published: March 2024

Mediterranean basins face significant water scarcity which requires examining long-term data to evaluate their trends in water availability and quality and assess management options. In this presentation, we explore the historical streamflow changes, the influencing climatic —streamflow, precipitation, temperature, and evapotranspiration (PET and AET)— and land-use factors, and the evolution of surface water quality in the Onyar River (Inner Catalan basins, NE Spain; 295 km2) during the last decades (1960-2020).Results highlight a consistent decline in streamflow, most pronounced over the last two decades, accompanied by an increase in PET, and a probable decrease in groundwater recharge. These changes co-occurred with higher concentrations of river water ammonium and nitrate. We attribute these patterns to changes in land use such as afforestation and intensive fertilization, as well as increased groundwater withdrawal, particularly during irrigation seasons. Additional factors include growing urban water demand and the discharges of treated wastewater back into the river system. Evaluation of the relationship between groundwater and surface water using end-member mixing analysis of hydrochemical data points out an interesting scale-dependence behaviour: groundwater baseflow from alluvial formations was relevant in the smallest subbasins, whereas regional groundwater flow involving deeper aquifers could significantly contribute to stream discharge in the lowest zones of the basin. Since water balance alteration in the future climate scenarios will reduce the contribution of the headwater flow as well as groundwater storage and baseflow generation, reclaimed wastewater shows up as a relevant source to maintain stream runoff, yet its quality is low and might not be properly diluted by rainfall originated runoff.These observations provide a comprehensive overview of the declining water quantity and quality in the Onyar River network, attributing these trends to an interplay of climatic and anthropogenic factors. They urge for integrated water resources management strategies to mitigate the implications of these environmental changes, such as protecting baseflow generating areas as well as controlling reclaimed wastewater quality.Funding: G. Córdoba-Ariza acknowledges funding from Secretariat of Universities and Research from Generalitat de Catalunya and European Social Fund for her FI fellowship (2022 FI_B1 00105). 
Changes of mesoscale eddy activity in the Eurasian Basin from 1-km simulations
Authors: Müller Vasco , Wang Qiang , Koldunov Nikolay , Danilov Sergey , Li Xinyue , Liu Caili , Jung Thomas
Published: March 2024

Mesoscale eddies play a crucial role in shaping the dynamics of the Arctic Ocean, making them essential for understanding future Arctic changes and the ongoing 'Atlantification' of the region. In this study, we use simulations generated by the unstructured-mesh Finite volumE Sea ice-Ocean Model (FESOM2) with a 1-km horizontal resolution in the Arctic Ocean.Our investigation includes multiple simulations, namely a seven-year run representing the present-day climate and a slice simulation for the end of the 21st century, representative for a 4°C warmer world. Through these simulations, we evaluate changes in Eddy Kinetic Energy (EKE) within the Eurasian Basin and analyze their correlation with factors like sea-ice cover, baroclinic conversion rate, and stratification. To deepen our understanding, we combine Eulerian properties like EKE and baroclinic conversion rate with Lagrangian properties obtained from an algorithm that automatically identifies and tracks eddies using vector geometry.Our findings from the end-of-century slice simulation indicate a significant increase in Arctic eddy activity in the future, accompanied by retreating sea ice. The present-day simulation reveals that the seasonality of EKE is mainly influenced by changes in sea ice, with distinct drivers at different depth levels for monthly anomalies. The mixed layer shows a robust connection to sea ice variability, while deeper levels, protected by stratification, are more significantly influenced by baroclinic conversion.
Will the MAGIC mission improve the observability of extreme hydrological events?
Authors: Boergens Eva , Wilms Josefine , Hauk Markus , Dahle Christoph , Dobslaw Henryk , Flechtner Frank
Published: March 2024

NASA and DLR will launch in 2028 GRACE-C (Gravity Recovery and Climate Experiment – Continuation). This mission will again be launched into a polar orbit at 500 km initial altitude and extend the observation of the time-variable Earth’s gravity field from GRACE (2002-2017) and GRACE-FO (GRACE Follow-On, 2018-today). ESA plans to launch a Next Generation Gravity Mission (NGGM) in 2032, which shall fly in a lower and inclined orbit and be based on improved instrumentation. GRACE-C and NGGM will then form the double-pair Mass-Change and Geosciences International Constellation (MAGIC) to significantly increase the spatial and temporal resolution of mass transport products and deduce water mass redistribution over the oceans, ice sheets and continents.Thanks to the 20+ years period of GRACE and GRACE-FO observations, scientists are able to analyse extreme hydrological events, such as flooding and droughts. However, due to the rather coarse spatial resolution of the GRACE and GRACE-FO data sets of approximately 350 km, finer spatial details of such extreme events are kept hidden. Further, spatial leakage limits the value of these data for smaller-scale regional investigations.In this contribution, we will employ five years of simulated data for both a single polar pair (GRACE-FO-like) and a MAGIC baseline scenario. Thanks to the simulation, we can also assess the true values of the hydrological input models. Both simulated data sets are filtered with the same DDK filters for comparison. The filter strength can be reduced for the MAGIC baseline scenario without introducing more striping errors.With these simulated data sets, we investigate extreme hydrological events. For example, the localisation of extreme wet events along the northern coast of Australia is much improved, with less signal leakage into the surrounding ocean.
Everywhere and Locally Relevant Streamflow Simulations in Hydrological Modeling
Authors: Shrestha Pallav Kumar , Samaniego Luis , Kumar Rohini , Thober Stephan
Published: March 2024

Contemporary initiatives such as the Digital Twins and paradigms like the Hyper-resolution Modeling are pushing the boundaries of high-performance computing, bringing resolutions of large-scale hydrological models (HM) down to sub-kilometer, in attempts of making "Locally Relevant Hydrological Models Everywhere" a reality. As global water models converge towards this hyper-resolution, we notice the insufficient attention given to model scalability i.e., consistent simulations across different resolutions using the same set of model parameters. Besides, the way distributed HMs have been resolving the stream network with grids requires high resolution model runs to offset the errors, especially at locations with smaller catchment area, hence the calling of the hyper-resolution modeling.We equip the mesoscale hydrological model (mHM, https://mhm-ufz.org) with a novel stream network upscaling scheme called subgrid catchment conservation or SCC. We hypothesize the conservation of the subgrid catchment area to have threefold effect in distributed HMs: 1) improvement in the consistency of model performance across modeling resolutions, 2) streamflow simulations become both plausible everywhere and locally relevant, and 3) the long-standing conundrum of streamflow estimation at multiple gauging stations within a grid cell will be solved.The experimental setup is a single modeling domain encompassing 187 GRDC streamflow stations in the Rhine river basin. The wide range of catchment sizes at the gauges (1 km2 to more than 150,000 km2), notable presence of proximate clusters of gauges, and good data availability (average availability of 30 years) makes Rhine an apt case for the hypotheses testing. We compare streamflow simulated by the SCC with the D8 stream network upscaling scheme, both with default parameter set. SCC shows remarkable streamflow scalability with nine out of 10 stations exceeding the mean flow benchmark across 1 km to 100 km model resolutions. In comparison, D8 shows poor scalability where the percentage of stations exceeding the benchmark reduces drastically from ≈80 % at 1 km to 50 % at 12 km to
Stable carbon isotope evolution of formaldehyde and implications for the origin of early Martian organic matter
Authors: Koyama Shungo , Yoshida Tatsuya , Terada Naoki , Furukawa Yoshihiro , Nakamura Yuki , Kamada Arihiro , Kuroda Takeshi , Vandaele Ann Carine , Ueno Yuichiro
Published: March 2024

Organic matter in early Martian sediments may provide a key to understanding prebiotic chemistry and habitability of Mars. The Curiosity rover has reported highly variable and 13C-depleted carbon isotope ratios of the organic matter in the early Martian sediments (House et al. 2022). However, its origin is unknown. One of the potential sources is the deposition of formaldehyde (H2CO), formed by photochemical reduction of CO2 in the atmosphere (Ueno et al., 2022). Here, we develop a coupled photochemistry-climate evolution model incorporating carbon isotope fractionation induced by CO2 photolysis, C escape, and volcanic outgassing. This model calculates the evolution of carbon isotope composition in H2CO in the early Martian atmosphere, beginning with an atmosphere composed of mantle-derived CO, CO2, and H2. The calculated evolution of carbon isotopic ratio in H2CO covers the extensive range observed in Martian organic matter, with its minimum δ¹³C value of ~-200‰. The calculated δ¹³C value of CO2 at approximately 4 Ga corresponds with those estimated from the analysis of the ALH 84001 meteorite. Our findings suggest that some organic matter in early Martian sediments could have originated from photochemically produced H2CO. If Mars was frozen but episodically warm in the late Noachian, surface ice containing the atmospheric H2CO (δ¹³C < -140‰) may have dissolved into Martian water bodies, leading to diverse carbon isotopic ratios in the resulting organic matter.
TOPAS-CH4: a service for methane monitoring, source attribution and emission reduction over Europe
Authors: Nanni Riccardo , Dernier van der Gon Hugo , Segers Arjo , Schaap Martijn , Tokaya Janot
Published: March 2024

Methane (CH4) is the second-largest contributor to the anthropogenic greenhouse effect, and have been the focus of recent climate summits and global commitments towards emission reductions. To mitigate and study the impact of anthropogenic CH4 emissions, the European Union started AVENGERS, a research and innovation project funded under the Horizon Europe, with 13 Partners from 6 countries, whose objective is to reconcile reported greenhouse gasses (GHGs) emissions with independent information from atmospheric observations using top-down methods and process-based models, and thereby reduce the most important uncertainties of national emission inventories.Here, we present TOPAS-CH4, an operational service developed by TNO as part of the AVENGERS project, following the example of a previous TNO source apportionment tool for particulate matter. This online public service provides users with the relevant daily information on CH4 concentrations over the EU countries, and how much different sources contribute to these observed  concentrations. TOPAS CH4 is based on the chemical transport model, LOTOS-EUROS, that runs daily to simulate source-labelled CH4 concentrations over Europe. The predicted CH4 concentrations are compared with the Integrated Carbon Observation System (ICOS) observations on a daily basis, showing that LOTOS-EUROS is able to realistically simulate the CH4 volume mixing ratios. Furthermore, the simulated CH4 concentrations are labelled per sector and country of emission, providing the users more insights about which European sectors and countries are mostly responsible for the additional CH4 concentrations above the background for a specific region. This information can be used to identify mitigation targets and, on the longer term, monitor changes in source contributions following successful abatement. We also show the comparison results for specific ICOS stations where the LOTOS-EUROS well matches the reported concentrations, as well as, locations where the model still performs poorly, finally providing some insights on how to improve the current simulation model.
Enhanced insight into Ghana's Seismicity through a Refined Crustal Velocity Model and Earthquake Focal Mechanisms
Authors: Mohammadigheymasi Hamzeh , Xiao Zhuowei , Mousavi S. Mostafa , Jamalreyhani Mohammadreza , Almeida Jaime , M. Garcia Nuno
Published: March 2024

This abstract presents the findings of a comprehensive seismicity analysis conducted in Ghana using the advanced Deep-Scan workflow [1]. The study compiled data from 461 earthquakes, revealing new insights into active seismogenic sources in this relatively under-explored region. A more accurate crustal velocity model is computed, and the detailed Green functions for focal mechanisms of detected events are estimated. Data integration from a single Ivory Coast station improved the azimuthal coverage of hypocenters, facilitating more precise velocity model estimations for deeper layers. The study utilized 5213 accurately picked arrival phases from 284 earthquakes, applying joint inversion techniques to optimize crustal velocity and hypocentral parameters. This resulted in a detailed 6-layer model, with P-wave velocity values ranging from 5.6 to 6.3 km/s and a high-velocity layer at 7.8 km/s, maintaining a consistent Vp/Vs ratio of 1.70. Analysis of the earthquakes revealed six compact clusters, predominantly aligned with the Akwapim fault zone and linked to the active section of the Romanche fracture zone in Axim. The distribution of hypocentral depths consistently falls within the range of 9-18 km, confined to the upper crust of the region. Utilizing the revised velocity model notably enhanced the identification of the seismogenic zone in southern Ghana. Moreover, it facilitated the generation of detailed Green functions for the next step for moment tensor (MT) inversion of small-magnitude earthquakes, employing a bootstrap-based probabilistic inversion schema. The results enhance our understanding of Ghana’s seismicity and represent key points for hazard and risk assessment in the region. This research is supported by Funda¸c˜ao para a Ciˆencia e Tecnologia (UIDB/00645/2020 and https://doi.org/10.54499/UIDB/00645/2020, and UIDB/50008/2020).References[1] H. Mohammadigheymasi et al., "IPIML: A Deep-Scan Earthquake Detection and Location Workflow Integrating Pair-Input Deep Learning Model and Migration Location Method," in IEEE Transactions on Geoscience and Remote Sensing, vol. 61, pp. 1-9, 2023, Art no. 5914109, doi: 10.1109/TGRS.2023.3293914.
Experimental study on high-temperature rheology of hot-pressed mafic granulite
Authors: zhang Qianqian , Zhou Yongsheng
Published: March 2024

The earth's internal dynamic processes are closely related to the rheological behavior of its internal constituent minerals under high temperature and high pressure conditions. Feldspar and pyroxene are the main constituent minerals in granulite in the continental lower crust. High-temperature experimental research on them is one of the main ways to understand the rheology of the continental lower crust. This experiment uses the Paterson high temperature and high pressure rheology device, at a temperature of 1273K-1423K and a strain rate of 6×10-6 s -2×10-5s-1, to test the hot-pressed feldspar and pyroxene aggregates with and without water respectively. Creep experiments were carried out under added water conditions to determine the rheological parameters of the two-phase aggregate under different water conditions. By collecting infrared spectra and microscopic pictures of the two-phase aggregate of hot-pressed feldspar and pyroxene, the water content in the samples before and after deformation was calculated and its microstructural characteristics were analyzed. The Q value of the sample without adding water is 797.87±184.7 KJ/mol, and the n value is about 3. The Q value of the water-added sample is 472.57±96.29KJ/mol. From 1273K to 1373K, the n value is about 2. At 1373K, the n value is about 4. This shows that water has a significant weakening effect on rocks.
Storm intensification driven by soil moisture gradients in global hotspot regions
Authors: Barton Emma , Klein Cornelia , Taylor Christopher , Marsham John , Parker Douglas , Maybee Ben , Feng Zhe , Leung L. Ruby
Published: March 2024

Organised thunderstorm clusters known as Mesoscale Convective Systems (MCSs) can bring high impact hazards such as flash floods, lighting and destructive winds. It is crucial for the forecasting and mitigation of these hazards to understand the processes that influence the characteristics of storms and thereby contribute to extreme events. Soil moisture is known to influence the initiation of MCSs in several regions of the world, but the influence of soil moisture on the later stages of MCS lifecycles is less well understood. Work in West Africa has revealed that dry soil moisture structures on scales > 200 km can increase the scale and longevity of propagating, mature afternoon MCSs, but this has not been investigated for other regions. In the current work we simultaneously analyse seven global MCS hotspot regions where storms may be sensitive to soil moisture, the US Great Plains, China, India, West Africa, Australia, South Africa and South America, to gain a more global perspective of the impact of soil moisture conditions on mature MCS characteristics. Using a combination of global datasets, storm tracks, satellite data, reanalysis data and CMIP6 simulations, we reveal that large-scale soil moisture gradients (100s of km) can intensify storms by driving favourable shear conditions through the strengthening of low-level atmospheric temperature gradients. By separating storms by soil moisture conditions, we show an increase in precipitation feature area and rainfall production on days with favourable gradients compared to days with unfavourable gradients. This is a newly identified mechanism through which soil moisture can influence storm hazards globally, which has implications for the forecasting and future projection of extreme events under climate change.
Towards in situ measurements of the chemical composition of Earth’s lower thermosphere
Authors: Fausch Rico , Wurz Peter
Published: March 2024

The chemical composition of Earth's lower thermosphere around an altitude of 180 km remains a largely uncharted territory. This altitude marks a critical transition region, where the atmosphere shifts from being dense and collision-dominated to a regime of free molecular flow. In this region, the altitude profiles of the present chemical species demonstrate their steepest gradients, a phenomenon crucial for understanding the dynamic interplay between the lower thermosphere and the mesosphere. Despite its importance, this region remains poorly explored due to limited in situ observations. Our focus is on the deployment of a highly miniaturized mass spectrometer, specifically designed for a CubeSat platform where it will be accommodated within 1U. This advanced instrumentation is designed to measure in situ all species present in this part of the atmosphere. Thanks to its novel ion source design, it is capable of measuring atoms, molecules, radicals, and isotopes, with exceptional sensitivity, dynamic range, mass range, and mass resolution even at the hyper-velocities of spacecraft during these measurements. The core of our discussion revolves around the expected data quality and performance capabilities of this mass spectrometer, particularly its operation at the perigee in the lower thermosphere. The data obtained from this innovative approach are expected to shed light on the complex dynamics at play in this scarcely studied region. We anticipate that these findings will significantly contribute to the scientific community’s understanding of the lower thermosphere, its coupling with the mesosphere, and the exosphere, filling a crucial gap in our current knowledge and potentially paving the way for future research in both atmospheric science and comparative planetology.
On quantifying the impact of CME magnetic flux and mass erosion on geo-effectiveness 
Authors: Maharana Anwesha , Dasso Sergio , Pal Sanchita , Asvestari Eleanna , Rodriguez Luciano , Magdalenic Jasmina , Scolini Camilla , Poedts Stefaan
Published: March 2024

Coronal mass ejections (CMEs) undergo erosion, deflection, and deformation upon interaction with the solar wind structures and with other transients during their propagation in the solar corona and heliosphere. In this work, we focus on the process of the erosion of CMEs in the heliosphere, which impacts their magnetic flux content, and its effect on altering their geo-effectiveness. To quantify the erosion of CME magnetic flux and mass in various solar wind environments, we employ 3D magnetohydrodynamic (MHD) simulations. 

To create a simulated solar wind background resembling a solar minimum period (for simplistic cases), we utilize the EUropean Heliosphere FORecasting Information Asset (EUHFORIA, Pomoell and Poedts, 2018) model. Through this background, we evolved a CME from 0.1 au to 2 au using a linear force-free spheromak model. We employ two distinct methods to assess erosion of magnetic flux and mass. 

First, the in-situ method, where the single point data at Earth or any other location is used to quantify the magnetic flux erosion. The orientation of the CME in the magnetic cloud frame of reference is determined through minimum variance analysis, and the accumulated axial and azimuthal flux is computed (Dasso et al, 2006). Imbalances in the flux profile serve as indicators of erosion. 

The second method relies on 3D simulation data, tracking the mass of the magnetic cloud in three dimensions based on criteria developed by Asvestari et al, 2022 for the spheromak model. With this method we can identify the 3D volume of the spheromak, assess its orientation, rotation, and magnetic properties in 3D in the local frame of reference of the spheromak structure. This technique provides us with the magnetic flux content of the spheromak and how it changes in space and time. 

Following a benchmarking process between the two erosion quantification methods, we conduct simulations to explore the sensitivity of CME erosion to variations in geometrical and magnetic field parameters. The study also investigates the influence of interactions with high-speed streams on erosion. Lastly, we apply an empirical Dst model (O’Brien and McPherron, 2000) to quantify geo-effectiveness and establish correlations with estimated erosion in all cases.
LES-based evaluation of UAV flight patterns to quantify local scale carbon emissions 
Authors: Bolek Abdullah , Schlutow Mark , Heimann Martin , Goeckede Mathias
Published: March 2024

Understanding carbon flux processes and controls is crucial to constrain greenhouse gas exchanges of different ecosystems under a changing climate. However, over heterogeneous landscapes (e.g., Arctic permafrost regions), carbon exchange fluxes (CO2, CH4) show significant variations even on very small spatial scales. As a result, upscaled carbon fluxes from eddy covariance towers and flux chambers hold the potential to be biased due to their limited spatial representativeness. Therefore, quantifying carbon fluxes at different scales is needed to improve understanding of spatial variability, and the interaction of processes over heterogeneous landscapes. Constraining carbon fluxes with unmanned aerial vehicles (UAVs) carrying greenhouse gas analyzers has the potential to bridge this scaling gap since UAVs allow to monitor large areas with high spatial resolution. Nevertheless, only few guidelines are available on UAV flight strategies and methods to accurately quantify the surface-atmosphere carbon exchange fluxes.In this study, we conducted synthetic UAV flights using a Large Eddy Simulation (LES) model to evaluate various carbon flux quantification methods based on UAV observations. These methods, including e.g. mass balance and flux gradient approaches, were tested with different flight strategies to find the optimum setup that maximizes information gain for a given flight time. In addition, we conducted experiments to improve the accuracy of the UAV-based carbon flux estimation from a campaign conducted in a subarctic heterogeneous ecosystem in which the UAV platform was able to collect in-situ atmospheric CO2 and CH4 concentrations, and environmental parameters such as 2D wind speed, air temperature, humidity, and pressure. Replicating these UAV flight strategies within the LES model enabled us to quantify the uncertainties and provide guidelines for future UAV flight campaigns in heterogeneous landscapes.
Environmental impact assessment of digital water meters throughout urban water cycle
Authors: Hajibabaei Mohsen , Oberascher Martin , Shahangian Seyyed Ahmadreza , Gschösser Florian , Sitzenfrei Robert
Published: March 2024

Utilizing digital measurement devices enhances the efficiency and reliability of urban water systems. For instance, digital water meters (DWMs) measure high-resolution water consumption at customer sites, serving both personal awareness raising and advanced water loss management in water distribution networks (WDNs). However, the pros and cons of these devices in terms of environmental impacts have yet to be fully unrevealed. This research aims to bridge this gap by conducting a comprehensive environmental assessment focused on the implementation of DWMs. The assessment considers not only the direct environmental impact of DWMs (e.g., due to production, installation, etc.) but also their indirect effects on the entire urban water cycle due to their usage. As an example of an indirect effect, using DWMs can reduce household water demand by promoting awareness. This leads to less freshwater treatment and pumping, decreased hot water and energy consumption in households, and a lower volume of wastewater generation. Thus, the current study categorizes the indirect effects on the urban water cycle into three scales: freshwater scale (including freshwater treatment and pumping energy), water user scale (involving energy consumption for water heating), and wastewater scale (including wastewater treatment).Life cycle assessment (LCA) is used as a holistic approach to quantify environmental impacts. Accordingly, the system boundary is defined to encompass the entire life cycle of DWMs (from production to end-of-life), as well as the three scales reflecting indirect effects. An Alpine city in Austria with 105,000 inhabitants is selected as a case study, where the impacts of deploying DWMs are evaluated by defining three scenarios according to the requirements of the study area. These scenarios include: (1) Reducing 5% of total leakage, (2) Reducing 15% of water demand, and (3) combining (1) and (2). For each scenario, comprehensive datasets on resources, processes, and energy consumption are compiled, and impacts are quantified using the LCA software SimaPro 9.0.Evaluating the environmental impacts of the study area in the existing situation (i.e., without any DWMs) shows that the water user scale (including energy for water heating) contributes to 80% of the total impacts. Thus, applying the second and third scenarios results in substantial energy savings across all scales (particularly water users) compared to the existing situation, reducing the environmental impacts ranging from 3 to 4 million kilograms of CO2 equivalent per year. This fluctuation is tied to the lifespan of the DWMs, extending from 2 to 8 years.The proposed framework can explore the extent to which DWM deployment is sustainable, providing a blueprint for decision-makers to assess the effectiveness of similar interventions in different urban settings.