bluuebunny/crossref_metadata_2025 huggingface dataset:
Ventilation changes in the Subpolar North Atlantic: Insights from Six Decades of Oxygen Observations and Tracer-Based Age Analysis
Authors: Stendardo Ilaria , Steinfeldt Reiner
Published: March 2024

The subpolar North Atlantic assumes a key role in ventilating the ocean’s interior as it is a primary site for deep water formation. Dissolved oxygen concentrations exhibit high sensitivity to climate variability and changes due to the interplay between sea-surface temperature fluctuations and ocean stratification. This relationship not only affects the solubility of dissolved oxygen but also modulates its transport from the near-surface ocean to the interior, known as ventilation. We collected sixty years of observations, spanning from 1960 to 2022, from three different datasets: GLODAPV2, WOD18 and BGC-Argo. These data underwent rigorous secondary quality control process, which adjusted biases between GLODAPV2 and WOD18, as well as BGC-Argo to minimize systematic errors. We conducted an in-depth analysis of the long-term changes and interannual variability in dissolved oxygen, apparent oxygen utilization (AOU), oxygen utilization rate (OUR) and water mass ages within the upper 2000 meters of the water column. Our specific focus encompassed the Subpolar Mode Water (SPMW), Intermediate Water (IW) and Labrador Sea Water (LSW). The computation of OUR and water mass ages in particular relied on tracer data such as chlorofluorocarbons (CFCs) and Sulphur hexafluoride (SF6) to estimate ventilation ages via the Transit Time Distribution (TTD) method. OUR provides insights into local oxygen consumption due to remineralization of organic matter, while the total AOU is the integrated OUR along the pathway of the water parcel. Therefore, identifying these parameters enables to distinguish between the primary drivers behind oxygen variations in the subpolar North Atlantic, namely air-sea gas exchanges, ocean circulation, and marine biology.
Human-induced alterations to the morphology of an urban Mediterranean watercourse from 1945 to 2022: transitioning from its natural state to phases of correction and restoration. 
Authors: Farguell Joaquim , Ferreira Filipe , Moreno Mariano , Barriocanal Carles , Schulte Lothar
Published: March 2024

Fluvial ecosystems are among the environments most significantly modified by human activities. Channelization, levee construction, floodplain disconnection from the riverbed, alteration of the fluvial regime and ecosystem, interruption of the sediment dynamics and alteration or destruction of the shape and morphology of the riverbed, are among the main effects of such interventions. Restoring or rehabilitating fluvial environments, including hydrological and geomorphological processes, is currently being undertaken in many river systems of the world given the benefits that these environments provide to mankind. However, depending on the magnitude of the human interventions and their impacts on the river system, reaching a restoration stage before human intervention cannot be fully achieved. In this context, the Congost River is a representative example of the evolution of the morphology of a river channel in the metropolitan area of Barcelona during the 20th and 21st century. The river flows through Granollers, a city of 60,000 inhabitants exposed to flood risk. During the 70s and 80’s the Congost river was channelized, narrowed and disconnected from its floodplain to promote urban and industrial growth.  The river channel was then fixed to avoid lateral migration by constructing sleepers (transversal structures), and fluvial landforms such as secondary channels and gravel bars were intentionally removed from the riverbed to create a drainage channel. However, to recover green riverine areas, sleepers in the peri-urban area of Granollers were demolished, whereas in the urban core area sleepers were conserved.Analysis of aerial images of 1945, 1956, 1986, 1998, 2009 and 2022 shows the following transformation: the natural braided channel, adapted to slope, flood frequency and sediment load changed after the human intervention to a restrained channel. The result of the restored river stretches showed higher hydro-morphological characteristics than the urban section, but they are still far from the expected outcomes of a fully successful restoration of a braided river. Yet, the channel morphology improves natural river processes. At this point, however, it is not known how the riverbed will evolve in terms of incision or avulsion, and whether further river management measures will be necessary to implement. Monitoring of channel evolution is required to fully understand the human impacts on partially restored urban fluvial systems through time. 
Interpreted 11-6 Ma age of Retrograde Metamorphism in the subduction channel of the Yuli Belt, Taiwan
Authors: Pang Chi-Hsiu , Yeh Meng-Wan , Lee Jian-Cheng , Iizuka Yoshiyuki
Published: March 2024

Based on petrological and geochronological studies of glaucophane-bearing schist in the Cenozoic Yuli metamorphic belt, Taiwan, as one of the world's youngest high-pressure (HP) terrane, we provide insights on the metamorphic ages, the metamorphic stages/microstructural fabrics, and the exhumation mechanisms of HP rocks.In this study we conducted field surveys of well-preserved mesoscale amphibole facies ultramafic schist outcrops along the Mayuan River, located in the Juisui area. We also carried out microstructural analysis using a microscope and SEM-EDS on oriented thin sections to distinguish different deformation stages/fabrics, along with quantitative EPMA analysis of the chemical composition of amphibole and phengite mineral. Furthermore, two different grain sizes (0.18mm and 0.25mm) of phengite were used to conduct the 40Ar/39Ar step heating dating analysis to determine the metamorphic age.Field observation identify S2 as the main foliation, shallowly dipping to the northwest or northeast in the Mayuan River area. The amphibole schist represents the rim of the ultramafic blocks within the matrix of the albite-quartz-mica schist. We also find a right-lateral west dipping shearing fault zone occurred between these two schists.By adopting main Phengite fabrics as S2, in microstructure domain, the prograde to retrograde metamorphism (subduction to exhumation) of 5 stages were identified: 1) S2-1, defined by rotated stubby subhedral phengite; 2) S2, defined by Phengite ± Epidote ± Calcic-amphibole; 3) S2+1, defined by Phengite ± Epidote ± Calcic-amphibole ± Chlorite; 4) S2+2, defined by Phengite ± Calcic-amphibole ± Titanite ± Albite; 5) and post-S2+2 phengite. The amphibole revealed varied zoned compositions and evidence of both “clockwise” (high-T to low-T) and “counterclockwise” (high-T low-P to high-P low-T) metamorphism from core to rim: from Pargasite to Edenite/Mg-Hb to Actinolite, Glaucophane to Winchite to Actinolite, and Pargasite to Winchite to Actinolite. Phengite grow in every 5 stages, and the 40Ar/39Ar dating yielded plateau ages of 10.7±1.6 Ma, 10.4±0.5 Ma, 8.8±0.6 Ma, 8.9±1.9 Ma, and 11.0±0.7 Ma, indicating cooling ages after the subduction stage with an estimated closure temperature of 410-420°C. One age spectrum showed a minimum age of 6.1 Ma, possibly representing a recrystallized age during exhumation.This study reveals the P-T-t path of the amphibole schists in the rim of ultramafic rocks in the subduction channel from subduction to exhumation. The clockwise and counterclockwise P-T path of the zoned amphibole indicated the complicated exhumation mechanism, and the retrograde metamorphism occurred in 11~6 Ma.
Pushing the time and space resolution for historical marine data: new datasets of sea-surface temperature and marine air temperature
Authors: Faulkner Agnieszka , Cornes Richard , Chan Steven , Siddons Joseph , Kent Elizabeth
Published: March 2024

Sea Surface Temperature (SST) and Marine Air Temperature (MAT) are essential climate variables (ECVs) and gridded datasets of these variables are used in many applications including global climate monitoring, evaluation of climate model simulations, providing boundary conditions for reanalysis datasets (in the case of SST) and for understanding air-sea interactions. While surface marine observations of MAT and SST extend back over 200 years, existing global high-resolution in-filled SST datasets span mostly from the early 1980s, which marks the start of satellite observations. Prior to that period, global datasets consist of monthly temperature values at a lower spatial resolution or areas limited to the location of observations without in-filling of grid-cells not covered by data.  

This work presents new global, in-filled datasets of SST and MAT. The SST dataset is provided at a sub-monthly, one-degree spatial resolution back to 1850, whereas the MAT dataset is generated at a monthly five-degree spatial resolution and extends back to the 1790s. As such it is the longest spanning in-filled air temperature record for the global ocean. 

The principal source of data used in these gridded datasets is the International Comprehensive Ocean-Atmosphere Data Set (ICOADS, https://icoads.noaa.gov/). Those data have been supplemented by newly recovered sources for certain regions and periods. The MAT dataset has been constructed solely using ship-based observations of air temperature whereas the SST dataset uses a combination of ship-based measurements and buoy data.  The ship data in both datasets have undergone a new processing procedure, with improved Quality Control (QC) flags, duplicate detection, improved work on the mis-positioning and mis-dating of some of the data sources and newly developed ship tracking method. For the SST dataset improved bias estimates for the measurements have been developed and have applied to the data. Gridded fields have been constructed from these quality-controlled/bias-adjusted values using ordinary kriging. Uncertainty values are provided with the datasets, and the derivation of these estimates will be described. 
Examining the fog occurrence over the Bucharest Henri Coandă International Airport and its adjacent area
Authors: Vlad Alex , Iorga Gabriela , Barbu Nicu , Stefan Sabina
Published: March 2024

Fog forecasting and fog nowcasting events are challenging issues especially when the fog phenomenon appears in the vicinity of airports because the reduced visibility associated with fog represent a high risk for air traffic events. Bucharest Henri Coandă International Airport (OTP, 44.57°N, 26.1°E, 95 m above sea level) is the largest airport in Romania and is located about 16 km north of Bucharest, the capital and most developed city of Romania. Its surroundings are comprised partly of residential and natural protected areas, and partly have agricultural use. Due to its geographic position, the airport is an important air traffic hub on the routes between western and eastern world destinations. In terms of numbers of flights, during the observation period analyzed here, the air traffic at OTP was significantly lowered during the spring of 2020 due to COVID-19 pandemic but soon after the restrictions were lifted and due to redirection of the flights over Ukraine after 2022, the air traffic is significantly increased in present.Data and analyses reported here cover a period of 2 decades from the beginning of 2003 to the end of 2023. Meteorological data, including fog events, relative humidity, wind speed and direction, were measured by the weather station of Romanian Air Traffic Services Administration ROMATSA R.A. Data about boundary layer and solar radiation was extracted from the public available database from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5.Present study reports the analysis of the evolution of the frequency of fog events and the relationships between fog events and speed and direction of the wind, and between fog events and the relative humidity. The correlations between the boundary layer height, solar radiation and the fog events were also investigated. Bivariate polar plots revealed fog appears with higher frequency (about 32%) during cold season, from October to March, and during early morning hours. Overview of the entire data set shows in some years mono-modal distributions of the fog frequency of occurrence with respect to the local time with peaks during the night and in the early morning hours and mono-modal flat distributions in other years. We observed the fog events are correlated with dominant wind directions of east-nord-east (ENE) and west-south-west (WSW). Statistical analysis of the data also showed a prevalence of the radiation fog over the advection fog.Acknowledgement: AV was supported by the University of Bucharest, PhD research grant. AV acknowledges the partial funding from the NO Grants 2014-2021, under Project contract no. 31/2020, EEA-RO-NO-2019-0423 project. Data regarding boundary layer and solar radiation was extracted from the public available database from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5. We thank ROMATSA R.A. for access to the database.
Investigation of Cloud Formation in the Atmospheric Boundary Layer with a Synergy of Radar and Lidar 
Authors: Alnayef Osama , Behrendt Andreas , Lange Diego , Branch Oliver , Wulfmeyer Volker
Published: March 2024

This research focuses on investigating the influence of dynamics and thermodynamics on cloud formation. The properties of the particles in dependence on relative humidity in the atmospheric boundary layer during cloud formation are investigated. For this, we use the synergy of Raman and Doppler lidars as well as of cloud radar operated during the Land-Atmosphere Feedback Experiment (LAFE) (see https://www.arm.gov/research/campaigns/sgp2017lafe). The LAFE project was executed at the Southern Great Plains (SGP) site of the Atmospheric Radiation Measurement (ARM) program in August 2017 in the USA.The particle backscatter coefficients are measured with Raman lidar, vertical wind velocity with Doppler lidar, and Doppler cloud radar. This instrument combination is also particularly advantageous for investigating the vertical structure of clouds, providing details about cloud height and thickness.In consequence, the combined measurements allow detailed insights into the relative humidity dependencies on the growth of particles to investigate the influence of dynamics and thermodynamics on cloud formation.
How P-nutrition status and the presence of non-essential metals (Al, REE) affect root carboxylate release and shoot element accumulation in plants with different nutrition strategies
Authors: Wiche Oliver , Maksimović Vuk , Stojanović Milica Stojanović , Ristić Dragica Ristić , Dragišić Maksimović Jelena
Published: March 2024

Rhizosphere processes related to nutrient acquisition and element exclusion overlap in time, space, and function depending on the composition of metal-chelating ligands released by plant roots in concert with rhizosphere pH. Thus, the presence of non-essential metals might influence the nutrient (phosphorus: P) acquisition in the rhizosphere, while processes related to nutrient acquisition might contribute to metal tolerance. However, until nowadays,  the interactions of essential and non-essential elements are poorly understood on a rhizosphere level. In the present study, we characterized the P-inefficient species Zea mays and Triticum aestivum with regard to their carboxylate release under conditions of P deficiency and compared the results with the P-efficient species Lupinus albus. In addition, we explored how the presence of microdoses of rare earth elements (REE) and aluminum (Al) alters carboxylate release and the shoot elemental composition of the plants. P deficiency increased carboxylate release in L. albus but not in T. aestivum. Lupinus albus released more carboxylates than T. aestivum did, regardless of the P-status. The exposure of plants to Al and REE in the early growth stage influenced biomass development, carboxylate release, and shoot elemental composition of mature plants. Notably, the effect of metal availability is clearly dependent on the plant species and the P status of the plants. The mechanisms remain poorly understood. However, these findings demonstrate that non-essential elements clearly shape chemical soil-plant interactions in the rhizosphere and have an impact on element acquisition.
TFMM: Advancing Air Quality Insights and Collaboration within the EMEP Framework  
Authors: Struzewska Joanna , Labrador Lorenzo
Published: March 2024

The Task Force on Measurements and Modelling (TFMM), established in 1999, operates within the framework of the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP). TFMM serves as a platform for the Parties of the United Nations Economic Commission for Europe’s (UNECE) Convention on Long-range Transboundary Air Pollution to exchange knowledge, share experiences, and develop recommendations on air quality issues.   TFMM offers a valuable opportunity for the Parties and EMEP Centres to engage in discussions regarding the performance of measurements and models. The focus is on getting improvements in methodologies, considering their diverse applications such as national assessments of air quality, evaluation of transboundary fluxes and their impact on air quality, trend analyses, and more.   Previous initiatives have encompassed comprehensive measurement campaigns and collaborative modelling exercises, contributing to the understanding of atmospheric processes across national borders.   In the upcoming 2024-2025 work plan a key focus will be a targeted measurement campaign.  Additionally, TFMM aims to conduct a comprehensive modelling exercise specifically geared towards the studying the impact of volatile organic compounds (VOCs) on ozone formation under heatwave conditions. In parallel, the work involves the exploration of the representation of aerosol chemical composition in air quality models.    Being a hub for collaborative efforts and scientific advancements within the EMEP framework, TFMM extends an open invitation to the scientific community and academia to actively join the TFMM experts’ community.  
Decadal changes of the snow in the western Tian- shan derived from in-situ snow depth measurements 
Authors: Mamaraimov Adkham , Gafurov Abror , Güntner Andreas , Bookhagen Bodo
Published: March 2024

Winter snow accumulation is important for summer water supply in Central Asia, and contributes more than 50 % to the annual runoff. The region’s water availability is highly dominated by snow reserves in the mountain, which will be affected by climate change. Volumetric snow data play a vital role for hydrologic forecast in mountainous river basins, where snow is considered as a dominating hydrological component. This study quantifies decadal snow depth changes in the Western Tian-Shan in the Chirchik River Basin in Uzbekistan. The snow depth measurements from Uzhydromet have been used in this research. The historical changes in snow depth has been statistically analyzed for the 1963-2020 hydrological years. Correspondingly, the impact of climatic factors (temperature and precipitation) on snow dynamics were assessed as well. The results of hydrometeorological parameters such as snow depth, air temperature at 2 meters and precipitation were plotted as the trend line on monthly, seasonal, and annual scales. To verify statistical significance of the trend dynamics, the slope method and the Mann-Kendall trend test were applied. Our results show that snow cover (duration) days were significantly decreased by 4 days per decade or 21 days for 57 years from 1963 to 2020. Particularly, the initial occurrence of a permanent snow onset day was significantly delayed by 3 days per decade or 16 days for 57 years. Likewise, annual peak snow depth day was significantly shifted earlier by 4 days per decade or 20 days for 57 years. Interestingly, the maximum snow depth did not change statistically significant, but we observe a decline of 3.33 cm per decade or 19 cm for 57 years. Overall, we conclude that the duration of snow cover (snow reserve) has significantly decreased in the Chirchik basin due to climate warming in the last 57 years.     
Monitoring landslides covered by vegetation using interferograms of different wavelengths
Authors: Strząbała Katarzyna , Ćwiąkała Paweł , Puniach Edyta
Published: March 2024

Detection of spatial and temporal deformations of landslides, along with the acquisition of precursor information, is crucial for hazard prediction and landslide risk management. Contemporary landslide monitoring systems based on remote sensing techniques (RST) play an important role in risk management and provide important support for Early Warning Systems. Research into the feasibility of using RST for monitoring different types of landslides also includes an analysis of the impact of radar wavelength on the obtained displacement results. The paper compares the time series results of landslide displacements obtained from satellite interferometric imaging in the C-band and L-band. The focus has been particularly on analyzing how the radar wavelength can impact the accuracy of the obtained displacement values and the ability to penetrate dense vegetation, especially under conditions of varying vegetation density. This poses a significant challenge for correct displacement detection. The obtained results are particularly relevant for geographical areas, such as Poland, where a large number of landslides occur in regions covered by dense vegetation. These are the conditions under which scientists encounter the greatest challenges in accurately monitoring these areas using radar systems. The final findings of the research are an important contribution to the development of landslide risk management strategies, crucial for the safety of people and infrastructure.
Uncertainties in modelling diagenetic self-organisation in limestone-marl sequences
Authors: Spreeuw Hanno , Hidding Johan , Hohmann Niklas , Jarochowska Emilia
Published: March 2024

Rhythmic variations in the properties of sediments are commonly used as archives of paleoclimate changes driven by variation in insolation caused by the changes in the Earth's orbit and the tilt of its axis. But rhythmicity can also arise from diagenetic self-organization. Distinguishing between these two drivers requires simulating self-organization. We started with an attempt to reproduce the main results from a paper by Ivan L'Heureux (2018)¹ - who proposed a mathematical model of a nonlinear dynamical system, in which self-organized oscillations arise from homogenous initial sediment and result in sediment layers with different compositions. The model consists of five stiff differential equations, for the composition of calcite and aragonite, two mineral polymorphs of CaCO3, of which aragonite is metastable, for the concentrations of calcium and carbonate ions in the pore water and for the porosity, as functions of depth and time. The self-organized patterns are in this model the result of two processes happening at different temporal scales: rapid dissolution of aragonite and slow sediment compression in response to increased porosity as aragonite is removed from the solid phase. Reproducing the steady-state distributions along depth required a major effort, mostly with regard to understanding what triggers numerical instabilities, but was finally successful.  Currently, we have not yet succeeded in reproducing oscillations, that L'Heureux predicted, without requiring an external force, for high initial and boundary sediment porosity.  It is essential that we are able to determine for which inital and boundary conditions oscillations should occur, beyond the uncertainties introduced by numerical algorithms for solving partial differential equations, e.g. for many sets of parameters the integrations over time can easily "derail". We have formulated two questions that we want to share with the audience in order to seek help. These are our questions: 

1) Do the five differential equations describe the underlying physics adequately?  2) Our current software implementation of the five differential equations does not yield any oscillations, is that a flaw on our side, or does this agree with mathematical insights?

"Diagenetic Self-Organization and Stochastic Resonance in a Model of Limestone-Marl Sequences" by Ivan L'Heureux (2018). https://doi.org/10.1155/2018/4968315
Paleoceanographic and paleoclimatic analyses throughout the MIS 5 interval: preliminary results from calcareous nannoplankton
Authors: Argenio Carmen , Flores José-Abel , Balestra Barbara , Amore Filomena Ornella , Hodell David , Abrantes Fatima , Alvarez Zarikian Carlos , Scientific Party Expedition
Published: March 2024

New insights about the Marine Isotope Stage (MIS) 5 over the North Atlantic area are presented in this study. The MIS 5 interval covers a timeframe from  ̴130 ka to 70 ka and it has been the last major interglacial interval occurred on Earth. In particular, the MIS 5e sub-interval, is a key period to study the possible evolution for human induced climate changes. It also represents an opportunity to interpret the natural climate evolution beyond the anthropic impact being interested by global temperatures assumed to be warmer than the pre-anthropogenic ones (e.g. Kopp et al., 2009). Likewise, the North Atlantic region is interesting for climatic studies being involved in the modulation of the global climate and in particular the Iberian margin is a well-known source of rapidly accumulating sediment offering a high-fidelity record of millennial climate variability.With this contribution we show preliminary results concerning changes in hydrography and coccolithophores productivity from two sites recovered on the Promontorio dos Principes de Avis, SW Iberian Margin: U1385 (37°34.285’N; 10°7.562’W – 2585 meters below sea level), drilled during the Integrated Ocean Drilling Program Expedition 339, and U1586 (37º37.283’N; 10º42.628’W - 4691 meters below sea level), drilled during the International Ocean Discovery Program Expedition 397.The phytoplankton group of coccolithophores has proved to be a high-quality environmental proxy since their geographic distribution and abundance is strongly influenced by parameters such as sea-surface temperature, salinity, sunlight and nutrient availability. Accordingly, coccolithophores are here used to describe paleoproductivity fluctuations in surface waters and upwelling strength as well as paleoceanographic changes linked to global climate evolution. ReferencesKopp, R.E., Simons, F.J., Mitrovica, J.X., Maloof, A.C. & Oppenheimer, M. (2009). Probabilistic assessment of sea level during the last interglacial stage. Nature, 462 (863-867)
From Margin to Menace: the role of structural inheritance in the geohazards distribution in Norway  
Authors: Osmundsen Per Terje , Redfield Thomas F.
Published: March 2024

Formation of the Norwegian rifted margin in the Mesozoic and Early Cenozoic and denudation of adjacent onshore areas resulted in preferential reactivation of regionally important Paleozoic faults and shear zones as indicated by a variety of published geochronological data. Lithospheric-scale necking impacted the later topographic evolution of the present onshore areas, including an escarpment topography and incision pattern that correlates with the seawards taper of the crystalline crust. The density of large, mapped landslides in turn reflects topographic and structural signals and tend to cluster inboard of sharply tapered areas. Margin formation also resulted in the impregnation of crystalline basement by swarms of smaller structures around multiply reactivated structures that made the bedrock prone for coastal erosion as well as onshore slope instability, with apparent maxima in glacially incised topography in areas inboard of sharply tapered margin segments in North- and Mid Norway as well as inboard of parts of the northern North Sea. Offshore, the sharply tapered Møre segment contains stacked submarine slide deposits in an anomaleously short progradational Quaternary wedge, illustrated spectacularly by the Holocene Storegga slide.  An important part of the geohazards distribution onshore and offshore Norway can thus be viewed as long-term responses to the rifting process through an interplay between crustal-scale inheritance, structural reactivation and saturation and mass redistribution by erosion, especially glacial transport. Other rifted margins that evolved by multiphase extension may display similar relationahips between ancient structural templates and the modern distributiion of geohazards.    
Surface Soil Moisture retrieval via change detection using SAOCOM L-band data over the Po Valley (Italy)
Authors: Brunelli Benedetta , Festa Davide , Mancini Francesco , Wagner Wolfgang
Published: March 2024

Synthetic Aperture Radar (SAR) has a high potential for measuring superficial soil moisture (SSM) dynamics over regional and global scales. Taking advantage of the continuous supply of Sentinel-1 C-band acquisitions, soil moisture is operationally mapped at kilometer-scale resolution using a change detection method (https://land.copernicus.eu/global/). However, the superimposed effect of the vegetation layer causes significant biases in the retrieval over densely vegetated areas or crop fields characterized by seasonal variations. L-band SAR data, due to their penetration capabilities through the canopy, are sensitive to SSM even where higher-frequency signal gets strongly attenuated. However, data availability has remained limited to a few space missions, e.g. ALOS and ALOS-2. Accordingly, limited applications have investigated the use of change detection models using L-band SAR satellite data.In the context of the current development of new active L-band satellites, such as SAOCOM (2018), ALOS-4 (2023), NISAR (2024), Tandem-L (2024), and Rose-L (2028) this work aims to explore the potential of SAOCOM data, which has become available since July 2022 over the European territory, to track soil moisture variations underneath crops and natural vegetation. L-band backscattering responses have been jointly evaluated in respect of Sentinel-1 data.A preprocessing workflow for SAOCOM Single Look Complex (SLC) acquisitions is developed to produce a 1 km co-polarized backscattering time series. The topics addressed are i) the improvement of coregistration between the different SAR sensors; ii) the use of radiometric terrain corrected gamma nought compared to the standard ground range detected (sigma nought) data; iii) the effect of SAOCOM acquisition strategies, such as incidence angle variation and inhomogeneous coverage, on the backscattering trends; iv) the optimization of the dynamic masking procedure to exclude low sensitivity pixel. Subsequently, the preprocessed scenes are ingested into an EO data cube (TUW-GEO/yeoda) and the well-established change detection method is implemented. The methodology is tested over the Po Valley (Italy), where the constellation achieves the highest revisit frequency. The resulting SSM product is compared to Sentinel-1 gamma nought retrievals and to modeled SSM from ERA5-Land reanalysis.Preliminary results show the potential of SAOCOM data for soil moisture mapping below the vegetation layer, which is essential for studying the effect of SSM climate-linked variations on vegetation growth, and could serve as a foundation for the development of multifrequency approaches.
Assessment of artificial riverbed recharge based on gravity investigation
Authors: Chen Kuanhung
Published: March 2024

Taiwan is grappling with a severe water scarcity issue, making the development and utilization of groundwater resources a critical national concern. In recent years, Taiwan's Water Resources Agency has been actively promoting the artificial recharge of groundwater resources in the Pingtung Plain to meet the increasing demands for domestic and industrial water use. This study focuses on five riverbed recharge facilities in the Pingtung AiLiao and Laonong River basins. A novel technique utilizing gravity methods to evaluate groundwater recharge volumes. This study utilizes gravity observations to directly monitor changes in groundwater storage, overcoming previous limitations associated with relying solely on monitoring wells to estimate groundwater recharge volumes. The study established two absolute and twelve relative gravity stations to collect data on variations in gravity over time and under different rainfall conditions. Preliminary results indicate that the average gravity value decreased by approximately 21 μgal over a 1.6 km2 area in December 2023, within a period of 3 weeks. The equivalent change in water volume will be verified with additional in-situ data. This research aims to compare the efficiency of recharge among different riverbeds in order to assess the applicability and limitations of this technique. Furthermore, we anticipate that this study will contribute to the dissemination of geodetic surveying techniques and their potential application in various hydrogeological and water resource fields.
 Microfiber behavior in turbulence and in quiescent conditions: insights from 3D high-speed measurements
Authors: Caridi Giuseppe Carlo Alp , Koolen Kevin , Soldati Alfredo
Published: March 2024

This research endeavors to enhance our understanding of the settling motions of microplastics in turbulence and in quiescent conditions. The scientific pursuit is fueled by the burgeoning environmental concern surrounding microplastics and the imperative need to refine predictive models for their behavior in different airflow conditions. Notably, existing drag models fall short in accurately predicting the settling velocities of microplastic fibers. The main goal of this study is to examine the settling dynamics of microfibers, particularly those with high aspect ratios. These microfibers are characterized by long, anisotropic (curved) geometries, with diameters ranging from 10 to 100 micrometers and lengths between 1 and 5 mm. 
 
The challenge lies in accurately measuring their trajectories and rotational rates during gravitational settling, both in a static environment and within controlled isotropic turbulence (Re_lambda=250). The integration of six high-speed cameras enables the three dimensional reconstruction of the time-resolved orientation of each fiber, providing velocity and rotational rate along their trajectories. The in-house tracking procedure is described in detail in Alipour et al. (2021) and Giurgiu et al. (2023) for water channel applications. In the present work, we showcase the applicability of this measurement technique in airflow scenarios, unveiling the intricate dynamics of microfiber-turbulence interactions and the gravitational settling of slender microplastic fibers in atmosphere.
 
References:
Alipour, M., De Paoli, M., Ghaemi, S., & Soldati, A. (2021). Long non-axisymmetric fibres in turbulent channel flow. Journal of Fluid Mechanics, 916, A3
Giurgiu, V., Caridi, G. C. A., Alipour, M., De Paoli, M., & Soldati, A. (2023). The TU Wien Turbulent Water Channel: Flow control loop and three-dimensional reconstruction of anisotropic particle dynamics. Review of Scientific Instruments, 94(9).
Development of a river breakup prediction model
Authors: Sæteren Marie , Engeland Kolbjørn , Kvambekk Ånund S. , Tallaksen Lena M.
Published: March 2024

The dynamic breakup of river ice can initiate ice runs where large masses of ice floes accumulate as ice jams. These ice jams can cause severe inundation and infrastructure damage. Several Norwegian rivers are prone to ice run events, however there are currently no models available in Norway for predicting this specific hydrological phenomenon. Ice-related problems are often dealt with on a site-to-site basis and rely heavily on local knowledge. Other countries, such as Canada and Sweden, have implemented statistical, machine learning and process-based modelling approaches. Being able to accurately predict the timing and severity of ice run and ice jam events improves the ability to take suitable mitigation measures and limit negative consequences. The aim of this work is to develop a model to predict ice run events in two Norwegian rivers, the Beiarn River and the Stjørdal River, and thereby address the need for predicting this hydrological hazard.The work presented here is part of a master thesis study that will be completed by May 2023. Both Stjørdal and Beiarn River have been monitored by NVE in the latter half of the 20th century, and the timing and severity of historical ice run events are obtained from this data. The predictors are given by hydrometeorological and ice thickness data, both observed and modelled. The Distance Distribution Dynamics (DDD) model developed by NVE is used for simulating daily discharge, and a simple ice growth model from NVE is used for modelling ice thickness. The prediction model itself is a work in progress, initially taking a logistic regression approach. If time allows, other approaches within machine learning such as random forest will be attempted. The dataset is severely imbalanced given the rarity of ice run events and the limited length of the observed series. Different methods are evaluated in terms of their ability to deal with this issue. The ultimate objective of this project is to develop a model providing daily probabilistic forecasts of the likelihood of ice run events in the coming days.
The International Methane Emissions Observatory (IMEO):  Integration of methane data across scales for policy-relevant results
Authors: Randles Cynthia , Zavala-Araiza Daniel , Baranski Marci , Calcan Andrea , Cifarelli Claudio , Demeter Meghan , France James , Guanter Luis , Irakulis-Loitxate Itziar , Watine-Guiu Marc , Schwietzke Stefan , Caltigirone Manfredi , Hamburg Steven
Published: March 2024

UNEP’s International Methane Emissions Observatory (IMEO) was established to provide reliable, public, and policy-relevant data to facilitate actions to reduce methane emissions.  IMEO is collecting and integrating diverse methane emissions data streams that will help to fill gaps in knowledge and refine global understanding of the location and magnitude of emissions across sectors.  Together these data streams – which include satellite remote sensing data, detailed analyses from multi-scale measurement campaigns, bottom-up inventory data, and measurement-based industry reporting – complement one another and provide a fuller characterization of the spatial and temporal variability in emissions than they do individually.  Knowledge of this variability is key to understanding the emissions of different populations of emitters and to identifying key mitigation opportunities for specific populations of emitters.  Such data can also be used as cross-verification points for other estimates of population-scale emissions – such as from inverse modelling or elsewhere reported emissions.  In this work, we will summarize IMEO’s efforts to assemble and integrate spatio-temporally dynamic methane emissions data including insights from measurement campaigns across the world, high-resolution methane emissions data from satellites, and developing standards for company-reported, measurement-based source- and site-level emission from the Oil and Gas Methane Partnership 2.0 (OGMP2.0). 
Deglaciation pattern of the last Scandinavian Ice Sheet across Fennoscandia
Authors: Boyes Benjamin , Dulfer Helen , Dewald Nico , Butcher Frances , Clark Chris , Ely Jeremy , Hughes Anna
Published: March 2024

Palaeo-ice sheets leave behind a landform record that we can decipher to understand glaciological processes and the responses of ice sheets to warming climates. Reconstructions of past ice sheet behaviour can inform numerical ice sheet models and are important for understanding ongoing glacio-isostatic uplift. The Scandinavian Ice Sheet, which was the largest component of the Eurasian Ice Sheet Complex during the last glaciation, glaciated Fennoscandia and northern Europe. Since the 19th Century, there has been considerable research into the deglaciation pattern of Scandinavian Ice Sheet during the last Glacial-Interglacial Transition. However, many reconstructions of retreat have been conducted at local-regional scales, which can be difficult to reconcile across ice sheet-scales, and ice-sheet scale reconstructions based on consistent approaches to mapping and data sources are rare. These inconsistencies lead to difficulties in creating ice-sheet wide reconstructions of deglaciation.Using the glacial inversion approach, we combine our independently mapped ice marginal landforms, subglacial meltwater routes, and subglacial bedforms to produce a consistent ice sheet-scale assessment of deglaciation patterns across Norway, Sweden, and Finland. Here we present our latest version of the deglaciation pattern for the last Scandinavian Ice Sheet. This reconstruction has many similarities to previous efforts but adds significant detail. For example, in addition to overall retreat patterns, we capture instances of ice margin readvance. We also reconstruct a complex retreat pattern with the ice sheet breaking into small ice masses located within and adjacent to the Scandinavian Mountains.
Sensitivity studies for the VeSUV/VenSpec-U instrument onboard ESA’s EnVision mission
Authors: Conan Lucile , Marcq Emmanuel , Lustrement Benjamin , Rouanet Nicolas , Vandaele Ann Carine , Helbert Jörn
Published: March 2024

The next ESA mission to Venus, EnVision, aims to study the planet as a whole, including its various constituting parts as well as their interactions and coupling processes. Several instruments will therefore compose the payload: a synthetic aperture radar (VenSAR, NASA), a subsurface radar sounder and a suite of three spectrometers (VenSpec) will be embedded, and a radioscience experiment will be implemented. Among them, the UV channel of the spectrometer suite, VenSpec-U, will observe the atmosphere above the clouds and will focus on the characterisation of the sulphured gases SO2 and SO, the monitoring of the unknown UV absorber and dynamical processes. These four topics have been identified as the main science objectives of the instrument and have driven the elaboration of a preliminary design based on the requirements (e.g. spectral range, spectral and spatial resolution) that were formulated with respect to these goals.The compliance of the current design with respect to these requirements, regarding in particular the precision of the retrieved science data, can then be assessed. Sensitivity studies are therefore performed using the Radiative Transfer Model (RTM), updated from the one used for SPICAV-UV/Venus Express retrievals (Marcq et al., 2020), that allows to link atmospheric features and UV reflectance spectra. Two types of perturbations are considered : errors of random nature arising from the presence of noise on the signal, or systematic errors caused by various effects that induce biases on the measurements. The first ones can be characterised through the influence of the Signal-to-Noise Ratio (SNR) on the uncertainties associated to each retrieved parameter through the fitting algorithm. Limits in terms of SNR can then be defined in order to ensure the compliance with the specifications. The second ones are referring to the impact of biases on the retrievals’ accuracy, and evaluate more specifically the effects of the similarities between the spectral characteristics of these biases and those of the atmospheric components aiming to be detected. The implemented method is based on the Effective Spectral Radiometric Accuracy (ESRA) requirement, previously defined within the framework of the ESA Sentinel missions. It allows to study biases independently as well as potential compensations, so that allowable envelopes of residual errors can then be estimated for each of the considered biases.
Atmospheric microplastics in the Arctic Region: An examination of deposited and suspended atmospheric microplastics in Ny-Ålesund, Svalbard
Authors: MacDonald Anna , Allen Deonie , White Christopher , Pheonix Vernon , Materić Dušan
Published: March 2024

Atmospheric microplastics (MPs) are an emerging environmental concern and have been reported globally, from large urban cities such as Beijing to remote regions such as Antarctica. Due to their small size, MPs can be transported large distances and pose a threat to human health, ecosystem function, and climate processes. However, significant gaps in knowledge surrounding the presence and characteristics of atmospheric MPs found in remote regions remain, especially in the polar regions. These are sensitive environments with relatively low levels of human activity, and play important roles in the earth’s climate and ecosystem health. Although atmospheric MPs have been reported in both the Artic and Antarctic, the importance of local and distal sources, and the roles atmospheric and marine transport processes, are unclear. By examining the presence of atmospheric MPs in this region and their transport, it is possible to gain more understanding of the global extent of MP pollution and the pathways which result in the presence of this pollutant in such pristine locations.  
Supported by the Norwegian Polar Institute, deposited and suspended atmospheric MPs were collected over a 28-day period between May and June 2022 at the Ny-Ålesund Arctic research station in (78°55’ N, 11°56’ E), using active and passive sampling. µRaman analysis was carried out to identify polymer composition, and Nile-Red staining has been used to examine the shape and size of these particulates.
Atmospheric MP concentrations for the Artic region are reported and the environmental implications discussed. This is the first time both suspended and deposited atmospheric MPs have been reported in this area, and this offers the opportunity to further understand the global extent and composition of this emerging pollutant.
Assessment of the potential of high temperature halogen chemistry in volcanic plumes for the oxidation of mercury
Authors: Roberts Tjarda , Nies Alexander , Kuhn Jonas , Geil Bastien , Terray Luca , Sonke Jeroen
Published: March 2024

Volcanoes contribute as a natural source to the global emission of mercury into the atmosphere. The emission of mercury takes place mainly in the gas phase, predominately as elemental mercury. But, several observations show different degrees of mercury oxidation in early-stage volcanic plumes. During the first seconds of volcanic plume evolution, hot magmatic gases mix with the atmosphere and the in-mixture of atmospheric oxygen triggers fast oxidation processes. These change the chemical composition of the volcanic plume drastically and lead to the conversion of hydrogen halides (e.g. hydrogen bromide and hydrogen chloride) into reactive halogen species. These reactive halogen species are well known to interact with mercury and promote the oxidation of elemental mercury towards divalent gaseous mercury.We present model studies investigating the first seconds of the evolution of a volcanic plume assessing the degree of mercury oxidation through reactive halogen chemistry. We utilize a new chemical box model that simulates chemical kinetics alongside cooling and dilution of the plume. The model is based on a chemical combustion mechanism coupled to an atmospheric chemistry mechanism, including sub-mechanisms for reactive halogens and mercury.  It shows that high-temperature halogen chemistry can potentially cause an oxidation of mercury in the percent range depending on emission temperature and mixing scenario. We compare these model calculations to mercury speciation measurements performed in near-source plumes at Mt Etna and Vulcano island in August/September 2023, where we find a relative abundance of divalent mercury of 5% and 37%, respectively. As well as showing evidence for rapid mercury oxidation, the field-observations at Vulcano indicate the potential for subsequent plume processes to cause mercury reduction.Model simulations in combination with field-measurements illustrate a complex behavior of volcanic mercury and halogens going from the hot emission to the cooled plume.