bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility study of a satellite-borne terahertz heterodyne spectrometer for the retrieval of atomic oxygen and temperature in the Earth's atmosphere
Authors: Hansen Peder Bagge , Wienold Martin , Hübers Heinz-Wilhelm
Published: March 2024

Atomic oxygen is one of the main species in the mesosphere and lower thermosphere (MLT) of the Earth’s atmosphere. Thus, atomic oxygen and the local temperature plays an important role for the energy balance in the MLT region. By remote sensing of the emission from the atomic oxygen fine-structure transitions at 2.06 THz and the 4.74 THz, atomic oxygen concentration profiles and neutral temperature profiles of the atmosphere can be derived.  By resolving the line profile, heterodyne spectroscopy enables access to layers of the atmosphere for which the oxygen line is saturated. The first spectrally resolved measurements of the 4.74-THz line of atomic oxygen in the atmosphere were performed with the heterodyne spectrometer GREAT on board of the airborne astronomic observatory SOFIA [1]. Based on the experiences from GREAT, the heterodyne spectrometer OSAS-B was developed as a balloon-borne instrument dedicated to the measurement of atomic oxygen in Earth’s atmosphere [2].In this study, we investigate the feasibility of a satellite-borne heterodyne spectrometer for the retrieval of atomic oxygen concentration and temperature in the MLT. Compared to airborne observations, a satellite instrument has the advantage of a limb observation geometry which facilitates the retrieval. A satellite instrument also has the advantage of a fast and almost global coverage.For investigating the feasibility of such an instrument, we use the vertical density and temperature profiles provided by the NRLMSIS 2.0 atmosphere model to simulate 2.06 THz and 4.74 THz emission spectra as measured by a satellite. We then apply retrieval algorithms for the atomic oxygen concentration and temperature and compare the retrieved profiles to the reference, i.e. the original NRLMSIS 2.0 profiles. We consider the scenario of a satellite in a circular orbit at an altitude of 500 km and an inclination of 8°. The emission spectra are simulated using radiative transfer under the assumption of local thermodynamic equilibrium.By considering two separate heterodyne receivers with sensitivity of 11,000 K and 25,000 K noise temperature for the 2.06 THz and 4.74 THz lines, respectively, and data accumulated over 100 seconds of measurement time, corresponding to a ground track of 700 km, we can retrieve a vertical temperature profile from 100 km altitude to 300 km altitude with 5 % relative uncertainties and an atomic oxygen concentration profile from 120 km to 300 km with 5 % relative uncertainties. From 100 km to 120 km the uncertainty in the atomic oxygen concentration is higher and within 25 %.[1] Richter, H. et al. Commun Earth Environ 2,19 (2021), doi: 10.1038/s43247-020-00084-5[2] Wienold, M. et al. 48th IRMMW-THz, Montreal, Canada (2023), doi: 10.1109/IRMMW-THz57677.2023.10299165
A new snow depth forecast data using cumulative distribution function matching in South Korea
Authors: Jeon Hyunho , Lee Seulchan , Choi Minha
Published: March 2024

Over the past decade, heavy snow has caused the third-largest amount of disaster damage in South Korea, following typhoons and heavy rain. To prevent damage from heavy snow effectively, it is necessary to forecast weather conditions. The Korea Meteorological Administration uses the Local Data Assimilation and Prediction System (LDAPS) to forecast hydrometeorological factors. However, the performance of LDAPS snow depth data is inferior to that of other models and requires correction. In this study, a cumulative distribution function (CDF) matching was used to correct LDAPS snow depth data. The CDF matching was carried out by utilizing ERA5-Land snow depth data to generate snow depth forecasting data for 12, 24, and 36-hour intervals. The forecasting data for snow depth is expected to generate snow disaster risk prediction data that can help reduce disaster losses on the Korean Peninsula.
Topographically constrained tipping point for complete Greenland Ice Sheet melt
Authors: Petrini Michele , Scherrenberg Meike D. W. , Muntjewerf Laura , Vizcaino Miren , Sellevold Raymond , Leguy Gunter , Lipscomb William H. , Goelzer Heiko
Published: March 2024

A major impact of anthropogenic climate change is the potential triggering of tipping points, such as the complete loss of the Greenland Ice Sheet (GrIS). Currently, the GrIS is losing mass at an accelerated pace, mainly due to a steep decrease in its Surface Mass Balance (SMB, snow accumulation minus surface ablation from melt and associated runoff). Here, we investigate a potential SMB threshold for complete GrIS melt, the processes that control this threshold, and whether it exhibits characteristics commonly associated with tipping points, such as a non-linear response to external forcings. To do this, we adopt a semi-coupled approach, forcing the Community Ice Sheet Model v.2 (CISM2) with different SMB levels previously calculated at multiple elevation classes with the Community Earth System Model v.2 (CESM2). The SMB calculation in CESM2 and the elevation class method allow us to account for the SMB-elevation feedback based on snow/firn processes and energy fluxes at the ice sheet surface. We find a positive SMB threshold for complete GrIS melt of 230±84 Gt/yr, corresponding to a 60% decrease from the GrIS simulated pre-industrial SMB. The ice sheet shows a highly non-linear response to sustained melt, and its final state is determined by the effect of the SMB-height feedback in response to surface melt and Glacial Isostatic Adjustment (GIA). The GrIS is tipping from nearly 50% equilibrium volume towards complete melt when the ice margin in the central west unpins from a coastal region with high bedrock elevation and SMB. We find that this relatively small coastal region is important to determine the ice sheet stability in response to sustained warming. Based on the ice sheet geometry in previous modelling studies of the GrIS during the last interglacial, we suggest that a stabilizing effect of the bedrock topography in the central West might have occurred in the past.
Determining the frequency of unfavorable conditions for sailing in Adriatic Sea channels 
Authors: Kožul Ena , Odak Plenković Iris , Muić Ines
Published: March 2024

The intricate coastline of the Adriatic Sea presents challenges for sailing, especially through narrow island channels in severe weather conditions. To plan construction work, an assessment was requested to determine the most favorable period for conducting maritime activities in two channels in the first half of the year, the Hvar Channel and the Korčula Channel. Motivated by that request, climatological analysis using available measurements of several meteorological parameters was conducted.Favorable conditions for sailing usually include weak or moderate wind intensity, often generated by island or coastal circulation. To determine the unfavorable conditions for maritime transport several meteorological parameters are examined with emphasis on wind, wave height, and thunderstorms, as these might contribute to the most hazardous sailing conditions in this region. The eastern coast of the Adriatic Sea is exposed to the strong winds blowing during the colder part of the year: the bora (northeast wind) and the jugo (southeast wind). Due to the orientation of the Adriatic Sea and analyzed sea channels, the jugo usually generates larger waves than the bora thus endangering maritime transport. However, navigating in strong bora conditions poses different risks due to its typically turbulent nature and strong intensity.With these considerations in mind, unfavorable navigation conditions are defined using three criteria: (i) wind strength reaching or exceeding Force 5 (Beaufort scale) and at least a moderate wave height, (ii) wind strength reaching or exceeding Force 8 regardless of the sea state, and (iii) the presence of thunderstorm conditions involving hail, thunder, and showers.In the analysis, it is concluded that the number of days with unfavorable conditions decreases from January to June, as expected. The most unfavorable conditions are most likely to occur in January, while June proves to be the most suitable month for conducting work with an average of 5.7 days with unfavorable conditions. Throughout all considered months, there should be at least 10 days with favorable conditions. Moreover, in June of any year, the number of days with unfavorable conditions did not exceed 7.
Seasonal Retrieval of Suspended Sediment in the Pearl River Estuary Based on Measured Data
Authors: Cai Shirong , Yang Xiankun
Published: March 2024

Suspended sediment is an important water quality parameter that plays an important role in regulating water and sediment dynamics in estuaries and shaping landform patterns. As one of China's important shipping channels, the sediment transport laws in the Pearl River Estuary (PRE) are very complex, which affects the water quality monitoring, pollutant transport, and offshore environmental and ecological protection of the PRE. This study takes the Pearl River Estuary as the study area, combines Landsat 8 images and measured data to construct suspended sediment inversion models in four seasons, and explores the seasonal patterns of suspended sediment concentration (SSC), to gain a deeper understanding of the transport mechanisms of suspended sediment in the PRE. The results show that: (1) From 2013 to 2021, there were significant seasonal differences in SSC. SSC was generally low during autumn and winter, and was higher during the dry season compared to the wet season. (2) At the interannual scale, SSC in the PRE exhibited a stable decrease. The suspended sediment is mainly concentrated at the estuary, and the spatial distribution pattern shows a distribution trend of higher on the west coast and lower on the east coast. (3) The suspended sediment in this region is influenced by various factors, such as upstream dam construction, seasonal rainfall changes, and land use changes. The findings of this study provide scientific insights for the sustainable development and ecological environment protection of the Pearl River Estuary, as well as suggestions for navigation safety and the security of infrastructure on both coasts.
Urban application of the AOTF-based NO2 camera 
Authors: Busschots Cedric , Gramme Pierre , Baker Noel Catherine , Dekemper Emmanuel , Casadio Stefano , Iannarelli Anna Maria , Di Bernardino Annalisa , Vanhamel Jurgen
Published: March 2024

To date, efforts to map ground-level NO2 distribution have primarily utilized visible-light scanning grating spectrometers, such as MAX-DOAS and Pandora. Although these instruments boast high retrieval accuracy, their spatiotemporal resolution remains relatively low, limiting the detection of dynamic features and strong spatial gradients.In recent years, a novel passive remote sensing instrument called the NO2 camera was developed at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB). This instrument aims to measure 2D distributions of NO2 slant column densities (SCDs) with enhanced spatiotemporal resolution over both extensive areas and in point-source plumes. Central to this instrument is the acousto-optical tunable filter (AOTF), providing both sufficient spectral resolution (~0.7nm) for resolving NO2 absorption cross-section structures and tunability across a broad spectral range.The measurement approach involves sequential acquisitions of monochromatic images of a scene. A hypercube is constructed by tuning the AOTF to specific wavelengths within the 440-450nm range. This hypercube is a 3D array with two spatial dimensions and one spectral axis.Conventional methods, such as DOAS, process the acquired light spectrum for each pixel's field of view to retrieve NO2 SCD. The hypercube resulting from a measurement with this AOTF-based NO2 camera is a 512x512 array of NO2 SCD values, taken at approximately 50 different wavelengths collected in around 1 minute, achieving a spatial sampling of less than 1 m, from distance of 1 km. Due to this high spatial resolution of the NO2 camera, the pixels that will be processed can be selected very carefully.Under the QA4EO IDEAS+ framework, the NO2 camera has been selected for further development. At EGU, we will present the results from the associated measurement campaign, performed in spring 2024 on the rooftop of the Sapienza University in Rome.This work is partially supported by the QA4EO contract QA4EO/SER/SUB/33.
Carbohydrate dynamics in Populus trees under drought: an expression atlas of genes Carbohydrate dynamics in Populus trees under drought: an expression atlas of differentially expressed genes across leaf, stem, and root
Authors: Fox Hagar , Ben-Dor Shifra , Doron-Faigenboim Adi , Goldsmith Moshe , Klein Tamir , David-Schwartz Rakefet
Published: March 2024

Nonstructural carbohydrates (NSC) management in response to drought stress is vital to understanding drought acclimation in trees. However, the molecular mechanisms underlying such processes remain unclear for most forest trees. Poplars are considered a model species for studying woody plants' molecular mechanisms. They are known to deploy a passive, symplastic sugar loading strategy, relying on sugars' concentration gradient through the plasmodesmata rather than on active sugar transport. Under drought conditions, tight regulation is needed to sustain long periods of stress and maintain water content. This study subjected young poplar trees (P. alba) to drought stress, following a combined analysis of sugar content and gene expression profile (RNAseq). We analyzed the expression of 29 gene families related to NSC signaling, translocation, and metabolism along three tree compartments (leaves, shoots, and roots). Starch depletion was evident in all organs, while soluble sugars accumulated only in the leaves, with an overall whole-tree decrease of ~30% in total sugar content. Our findings highlight relevant genes that specialize in triggering drought metabolism, starch depletion, sugar immobility, and osmotic adjustment. Broadly up-regulated genes are highlighted, as well as tissue-specific ones. This research provides a broad overview of the molecular process underlining NSC dynamics under drought in poplar trees.
Estimation of extreme electron fluxes at geostationary orbit: a statistical and a physical approach
Authors: Savola Mikko , Osmane Adnane , Turc Lucile , Kilpua Emilia , Palmrooth Minna
Published: March 2024

The outer Van Allen belt is home to relativistic electrons and experience large variations in electron fluxes during geomagnetic driving events. Many satellite orbits, especially geostationary ones, overlap with the radiation belts and experience high-energy electron radiation. This radiation causes surface and internal charging, accompanied by aging of satellite components. In order to determine the impact on satellites during strong and extreme geomagnetic storms, one needs to quantify the magnitude of the fluxes. In this communication, we compare two different methods for estimating large flux values at geostationary orbit. The first method is physical and relies on the Kennel-Petschek limit (Kennel&Petschek, 1966). The second method is purely statistical and originates in extreme value theory (Coles, 2001). Using extreme value theory (EVT), for electron energies of 130 keV, we find for the once in 150 years electron flux an expected value that is two orders of magnitude larger than electron flux during the Halloween storm of 2003. On the other hand, the Kennel-Petschek limit, for the 130 keV electrons at L=6.7, which corresponds to geostationary orbit, is 1/6 of the maximum of the Halloween storm flux. The EVT therefore provides much larger estimates than the Kennel-Petschek limit. We compare the two methodologies with their respective strengths and limitations and determine under which conditions they should be combined to estimate extreme fluxes in the radiation belts. 
Could planetary scale solar radiation management prevent a West Antarctic Ice Sheet collapse? 
Authors: Sutter Johannes , Frölicher Thomas , Jones Anthony , Wirths Christian , Stocker Thomas
Published: March 2024

Solar radiation modification (SRM) is increasingly discussed as a tool to reduce or avert global warming and concomitantly the risk of ice-sheet collapse, as is considered possible for the West Antarctic Ice Sheet (WAIS). While there is a growing body of literature on the climate impacts of various hypothetical SRM employment schemes, the concomitant effects on ice sheet dynamics are much less studied let alone understood. We present the first study explicitly modelling the Antarctic Ice Sheet response to global SRM-interventions with a continental scale ice sheet model. Intuitively, the question whether a WAIS collapse can be prevented depends on a manifold of factors such as ice sheet sensitivity, timing and design of the SRM-intervention and underlying climate scenarios. Our study suggests that safeguarding the WAIS from long-term collapse would either require rapid decarbonization efforts or quasi-immediate SRM-interventions. Both cases are either politically unrealistic or imprudent considering the precautionary principle. We discuss the response of the Antarctic Ice Sheet under various climate and SRM scenarios and the associated uncertainties which need to be resolved to get a more conclusive understanding on the impact of SRM-geoengineering strategies on earth’s two remaining large ice sheets. 
A semi-analytical approach to characterize the effects of unsteadiness and dune migration on microplastics fate
Authors: Marzadri Alessandra , Portillo de Arbeloa Nerea , Tonina Daniele
Published: March 2024

Streams and rivers, together with their bed (i.e. benthic) and subsurface (i.e. hyporheic zone) environments represents the natural connectors between terrestrial and aquatic environments through which transport and transformation processes control the fate of a multitude of elements, including nutrients and contaminants, commonly produced by human activities. In recent years, particular attention was given to a new class of pollutants known as Contaminants of Emerging Concern (CECs) that include, among others, microplastics. Microplastics enter the streams and rivers after escaping degradation from wastewater treatment plants (WWTPs) and during the time they spend within the riverine environments they may have potential adverse effects on human and freshwater ecosystems. Among the different processes that affect their fate, burial within the streambed sediments is still the subject of current research; especially considering that under some hydrodynamics conditions small scale bedforms (i.e. dunes and ripples) can migrate causing hyporheic exchange to depend on both bedform migration, called turnover, and near-bed pressure gradients, called pumping. Here, we analyze the effects of turnover and pumping in sand-bedded streams with mobile dunes by proposing an analytical solution of the process. The proposed analytical solution allows us to determine: i) the pressure head distribution, ii) the velocity field and iii) the residence time distribution within a homogeneous stream bed sediment under transient conditions of the stream flows. The solution allows to characterize and quantify the penetration depth and the release (i.e. the resuspension process) of microplastics due to the trapping-releases successions as hyporheic pathways (connecting downwelling and upwelling zones) change in time.
Sub-daily seismic velocity changes as indicator for large vulnerable groundwater reservoirs
Authors: Kramer Richard , Lu Yang , Wang Qingyu , Bokelmann Götz
Published: March 2024

We use an adapted approach for long-distance high temporal resolution monitoring to investigate the daily and sub-daily behavior of seismic velocity changes. We analyze four years of continuous data from AlpArray and other local networks throughout the Central-Southern Europe. Focusing on the 1 Hz frequency we calculate seismic velocity changes based on coda wave interferometry. Our results show that we can observe a consistent periodic behavior with periods of 24 h and 12 h, with a focus primarily on the latter. We attribute these changes predominantly to variations in atmospheric pressure. These changes manifest through loading effects on the unsaturated zone and alterations in the water bodies below that.  By analyzing the spatial variations of this two-cycle-per-day behavior we found a strong correlation with extensively karstified water-bearing formations. This connection may contribute to the hydrological characterization of the near-subsurface in central Europe identifying large water reservoirs.
Blue carbon burial along intertidal mudflats
Authors: Sanders Christian , Wang Faming
Published: March 2024

Coastal blue carbon habitats perform many important environmental functions, including long-term carbon storage. These carbon storage estimates are typically limited to the sediments within specific types of coastal vegetation. However, recent studies have shown that large fluxes of organic carbon originating from traditional and non-traditional blue carbon systems are being buried along the margins and intertidal mudflats. For example, our recent study in China showed that over 75% of the blue carbon burial occurred in unvegetated tidal flats. Further, in Brazil, organic carbon burial rates along mudflats were found to be almost 3 times greater than the flux from within coastal vegetated systems. The implications of this research are that there is an underestimation of carbon burial from blue carbon systems as a result of the large burial rates along adjacent unvegetated regions.
Transition from slow to fast tearing instability in the kinetic regime: theory and simulations
Authors: Innocenti Maria Elena , Dargent Jeremy , Pucci Fulvia , Schoeffler Kevin , Boella Elisabetta
Published: March 2024

Current sheets are ubiquitous in space and astrophysical plasmas, and may become unstable, under appropriate conditions, to the so-called tearing instability, which in turn triggers magnetic reconnection and massive magnetic to kinetic energy conversion.Over the past decade, significant progress has been made on the initiation of fast reconnection via plasmoid instability in resistive plasmas. However, given the extremely high Lundquist numbers in most natural plasmas, the role of kinetic effects in breaking the frozen-in condition and triggering tearing instability has to be considered.In this work, we observe by means of fully kinetic Particle In Cell simulations the onset of a fast tearing instability (e-folding time τ∼τA, with τA the Alfven time) in current sheets (CS) with thickness a>di, with di the ion skin depth.We adopt the model for the transition from slow to fast tearing instability described in Pucci et al 2017 in the kinetic regime and in a double CS framework, where the electron inertial term replaces the resistive term as the dominant non ideal term in the generalised Ohm’s law in the vicinity of the neutral line. We show that the simulations verify the model predictions on the critical current sheet aspect ratio (thickness to length) below which the tearing instability growth rate is expected to approach the Alfven time (“fast tearing”).
Hydrological flow modelling with SWAT: a useful GIS based tool to assess hydropower production.
Authors: Paschetto Arianna , Caselle Chiara , Bonetto Sabrina , Leso Claudia
Published: March 2024

Europe's pursuit of climate neutrality by 2050 necessitates innovative strategies in renewable energy deployment. The European Union has championed policies to harness clean energy sources as hydroelectric energy. This study delves in Piedmont region (North-West of Italy), evaluating its residual potential for run-of-river hydroelectric plants. More in detail, the research focuses on the Sangone catchment, aiming at performing a regional-scale study made to identify the best sites for potential hydroelectric plants. To ensure alignment with European Union biodiversity and environmental conservation directives, particularly the Habitats Directive and Birds Directive, the research prioritizes sites that are not in areas dedicated to environmental protection.Moreover, the study includes landscape analysis and evaluation of geological and geomorphological constraints, such as landslide and hydraulic hazard, and technical and economic feasibility of plants.After that, utilizing freely accessible data encompassing temperature, precipitation, land use, and soil characteristics specific to Piedmont, the study employed the Soil and Water Assessment Tool (SWAT).This GIS-integrated hydraulic model extrapolated flow rate metrics for water catchment areas devoid of direct measurement, optimizing site selection for maximal hydroelectric energy yield.The simulation used 17 years of meteorological data from 42 measuring stations and the model was run over the Sangone stream catchment. The model has also been calibrated to simulate runoff in the Sangone catchment. The outputs divide the stream in sections with equivalent potential power production. Preliminary findings underscore the effectiveness of SWAT by using free data and free tools. It can be a useful planning tool for hydropower implementation by locating sites suitable for run-of-river plants, considering environmental impact and geo-hydrological hazard. As Europe navigates its green transition, such integrative approaches emphasize the feasibility and sustainability of hydroelectricity as a linchpin in the continent's renewable energy matrix.
Lambda-Miner: Enhancing Reproducible Natural Organic Matter Data Processing with a Semi-Automatic Web Application 
Authors: Wurz Johann , Groß Anika , Franze Kai , Lechtenfeld Oliver
Published: March 2024

As the volume and complexity of data in environmental sciences continue to grow, the need for data management and reproducible processing methods becomes increasingly crucial. In the specific research domain of natural organic matter (NOM), there is currently no standardized tool for data processing, particularly for the management of data and its respective metadata. We developed and present the Lambda-Miner - a semi-automatic web application for data processing of ultrahigh-resolution mass spectrometry data of NOM. The platform provides an end-to-end data processing pipeline and supersedes manual steps via standardized data and metadata management. It empowers users to execute interactive workflows for mass spectra calibration, assignment of molecular formulas by specific rules to peak masses, and validation of these formulas according to specific sets of rules. Peak data as well as sample and measurement metadata are stored in a relational database management system (RDBMS). The Lambda-Miner thus facilitates reproducible, standardized data processing which builds a common repository for mass data, metadata (such as sample type and geolocation), intermediate, and final results in a format suitable for subsequent analyses. The combination of this information in one place enables meta-analyses such as long-term quality control studies and software optimization assays. The Lambda-Miner supports domain-specific requirements for research data management and contributes to achieving FAIR data principles in the domain of NOM analytics. The Lambda-Miner allows researchers to process their ultrahigh-resolution mass spectrometry data of NOM within minutes and linking it to features such as extraction efficiency, accumulation time, and relation of total assigned current to total ion current. Processed data can be downloaded in an interoperable format, facilitating individual data processing or visualization. The current implementation of the Lambda-Miner is designed for studying NOM with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) allowing formula assignments with widely used elemental compositions of NOM in the mass range from 0 to 1000 Da. But its modular structure makes it easy to adjust and extend the implementation for other kind of analyses or instrumentations. With its adaptability and focus on reproducibility, the Lambda-Miner introduces a valuable tool for advancing standardized data storage, processing, and analysis in the study of Natural Organic Matter.
A novel helicopter-borne application for quantifying methane emissions from industrial activities: Results from measurements of coal mine ventilation shafts in Poland
Authors: Förster Eric , Huntrieser Heidi , Lichtenstern Michael , Pätzold Falk , Bretschneider Lutz , Lampert Astrid , Necki Jaroslaw , Jagoda Paweł , Swolkień Justyna , Holl David , Field Robert , Roiger Anke
Published: March 2024

The Upper Silesian Coal Basin in southern Poland is one of the strongest emitters of anthropogenic methane (CH4) in Europe. Coal mine ventilation shafts are responsible for a major part of these CH4 emissions, which were in focus of the METHANE-To-Go-Poland project presented here. For the first time, the unique helicopter towed probe HELiPOD was used to estimate CH4 mass fluxes from selected ventilation shafts based on the mass balance approach. The HELiPOD (weight 325 kg, length 5 m) was equipped with a sensor system for measuring the 3D wind vector and in situ methane analysers (Picarro G2401-m and Licor-7700) to measure CH4 with a high precision (1 ppb) and high temporal resolution (up to 40 Hz). In June and October 2022, repeated upwind and downwind probing of four selected shafts were performed within 16 flights at different horizontal distances from the source (~500 m - 5 km) and altitudes (~50 m – 2 km) to capture the inflow and horizontal/vertical dispersion of the CH4 plumes. Depending on wind speed, wind direction and atmospheric stability, suitable flight patterns were developed for every flight. Co-located mobile ground-based CH4 measurements complemented the airborne probing. In addition, two controlled CH4 releases were successfully carried out to prove the novel measurement concept.In this presentation, top-down mass flux estimates based on measurements from the two airborne CH4 instruments (with different temporal resolution) will be compared and mass flux uncertainties will be discussed with respect to the flight strategies and meteorological conditions. Depending on the surveyed shaft, the calculated CH4 mass fluxes range from 1000 to 3000 kg/h. Subsequently, the top-down mass fluxes will be compared to bottom-up mass flux calculations based on production data obtained directly from the coal mine industry.Our calculations are an example of the independent emission verification technique and will help coal, oil and gas companies as well as governments, to prioritize their CH4 emission mitigation strategies, actions and policies. This research has been funded in the framework of UNEP's International Methane Emissions Observatory.
Paleoceanographic changes in the Northern Benguela region inferred from the planktonic foraminifera assemblages during the Pleistocene 
Authors: Del Gaudio Arianna Valentina , Avery Aaron , Auer Gerald , Piller Werner E. , Kurz Walter
Published: March 2024

The Benguela Upwelling System (BUS), situated in the Southeastern Atlantic Ocean, is known as the most productive wind-driven coastal system on Earth. The BUS is boarded to the north and to the south by the Angola Benguela Front (ABF) and the Agulhas retroflection region, respectively. The ABF is a permanent thermal frontal feature located at around 16°S, which separates the cool Benguela Ocean Current (BOC) from the northernmost Angola warm water masses (e.g., the South Atlantic Central Waters; SACW). The Agulhas retroflection region, instead, represents an area, in the southernmost sector of the BUS, where the Agulhas current (AgC) retroflects towards the Indian Ocean, due to westerlies' stress curl. However, eddies of the warm and saline Agulhas waters can access the southern Atlantic Ocean and subsequently mix within the Benguela current.In this work, statistical analyses (cluster and PCA analyses, Globorotalia truncatulinoides coiling ratio, and the Agulhas Leakage Efficiency Index) were applied to the planktonic foraminifera assemblages in 94 samples from Holes U1575A and U1576A, collected during International Ocean Discovery Program (IODP) Expedition 391. Precisely, the sites were drilled along the Tristan-Gough-Walvis Ridge (TGW) seamount track, in the northernmost sector of the BUS, at increasing distance from the Namibian continental margin. The investigated record corresponds to the Early to Late Pleistocene, which comprises the Early-Middle Pleistocene Transition (EMPT). The EMPT is an interval in the Earth history spanning from 1.40 to 0.40 Myrs and characterized by prominent glacial to interglacial sea surface temperature (SST) variations.Our results provide new understandings on the regional paleoceanographic changes occurring within the northern part of the BUS, based upon the ecology and distribution of the planktonic foraminiferal assemblages. Specifically, changes in the assemblage composition during the Pleistocene permitted the characterization of the different water masses (BOC, SACW; AgC) and their interplay, as well as the reconstruction of the local variations of the thermocline in the BUS. The interaction between the water masses mentioned above, produces changes in the BUS such as the fluctuations of the ABF and the influx of the AgC waters from the Agulhas retroflection area.Moreover, we further examined the possible correlations between the paleoceanographic variability and climatic events (e.g., Benguela Niño/Niña-like states and deglaciations phases), which occurred since the onset of the EMPT.
Overview of SWOT ocean surface topography performance 
Authors: Prandi Pierre , Raynal Matthias , Cadier Emeline , Nencioli Francesco , Flamant Benjamin , Dibarboure Gérald , Stiles Bryan , Ubelmann Clement , Delepoulle Antoine
Published: March 2024

The SWOT mission was launched in December 2022. Its first of a kind KaRIn instruments provides two dimensionnal images of ocean surface topography over a 120 km wide swath. Ocean surface topography data quality and mission performance have been assessed and monitored over the first year of SWOT mission, as part of mission performance activities performed by the mission project.

Here we present a synthesis of SWOT mission performances over ocean: from data availability and validity to end-to-end performance metrics (eg SSH differences at crossovers, wavenumber spectrum and comparison with the current nadir altimetry constellation). We also discuss the performance of cross-calibration algorithms at level 2 (based on crossovers) and level 3 (based on other altimeters). Results presented here are based on the analysis of the 2 km product during both the calval (1 day repeat orbit) and science (21 day repeat orbit) phases and focused on ocean surface topography retrievals. All mission CalVal metrics highlight the excellent performance of KaRIn measurements.  

We also present some known limitations of current SWOT products that are of interest to science users.
Using single-grain feldspar luminescence signal and modelling to study landscapes erosion rates and sediment transport
Authors: Guyez Anne , Bonnet Stephane , Carretier Sebastien , Wilkinson Clare , Reimann Tony , Norton Kevin , Wallinga Jakob
Published: March 2024

Luminescence is a powerful dating technique that is increasingly being used as a new tool to investigate surface processes. In the past decade, it has been used successfully for instance to estimate virtual sediment velocity in rivers, sediment storage time in floodplains, and to trace sediment sources (McGuire & Rhodes, 2015; Gray et al., 2018; Sawakuchi et al., 2018; Guyez et al., 2022; Guyez et al., 2023). As part of ongoing development, here we quantify sediment transport and catchment-wide erosion rates in natural systems using luminescence. For this purpose, single-grain post infrared-infrared (pIRIR) equivalent doses of felspars from modern floodplain deposits were measured in several catchments in the Southern Alps of New Zealand and compared to catchment-wide erosion rates derived from 10Be cosmogenic nuclide concentrations measured in fluvial quartz grains.The fraction of grains that were well-bleached before their burial in the modern floodplain was calculated, as well as the fraction of grains with a saturated luminescence signal. Signal distribution was characterised using the central age model.Our findings indicate that the luminescence signal is characterized by few well-bleached grains and lots of grains with a high luminescence signal where erosion rates are high. On the other hand, in catchments with lower erosion rates, bleaching appears to be more pervasive, resulting in an overall lower luminescence signal. Therefore, we hypothesize that bleaching efficiency is related to erosion rates.To test the relationship between luminescence, bleaching, erosion, and transport processes, we include the luminescence signal of individual grains in a landscape evolution model that already takes into account the concentration of cosmogenic nuclides (Carretier et al., 2023). By tracking both signals in an evolving stream basin, the model helps better understanding the relationship between erosion and luminescence signal, on longer time scales. Single-grain pIRIR equivalent holds promise as a new method for measuring erosion and sediment transport.
Spatial variation in soil hydraulic properties in an agricultural field estimated using Tension Disc Infiltrometer
Authors: Vashishth Nirali , Dey Souradip , Ojha Dr. Richa
Published: March 2024

Understanding spatial variation in soil hydraulic properties is important for comprehending the physical behaviour of soil and for analysing field-scale water flow and solute transfer processes. Tension disc infiltrometers are commonly used for measuring in-situ unsaturated hydraulic properties of soil. In this study, spatial variation in soil hydraulic properties is analysed for an experimental plot at IIT Kanpur, India after harvest of rice crop using tension disc infiltrometer. Measurements were taken at three different depths of 10, 25 and 50 cm and at multiple locations in the field for consecutive supply pressure heads of -12, -9, -6 and -3 cm. The measured data was analysed using HYDRUS-2D model and four Maulem-van Genutchen parameters (θs, α, n and Ks) were inversely estimated. The maximum variation was observed in α at the depth of 50 cm. The reduced variability observed in pore size distribution index (n) could be attributed to the flooded irrigation practice in rice. The findings of this study enhance our understanding of soil-water interaction in agricultural settings.Keywords: Soil hydraulic properties, Tension disc infiltrometer, HYDRUS-2D
Global-scale plant trait-environment relationships based on sPlotOpen and TRY data
Authors: Dechant Benjamin , Pavlick Ryan , Kattge Jens , Schneider Fabian , Sabatini Francesco M. , Moreno-Martinez Alvaro , Kattenborn Teja , Bruehlheide Helge , Townsend Philip A.
Published: March 2024

Relationships between plant functional traits and environmental variables have been intensively studied in the ecological community due to their importance for applications such as generating upscaled trait maps and predicting trait responses due to climate change. However, such relationships have been found to be relatively weak for various potential reasons.We analyzed global-scale trait-environment relationships using plot-level trait estimates based on the sPlotOpen and TRY databases. In addition to the commonly used community weighted mean (CWM), we considered a top-of-canopy weighted mean (TWM) metric that excludes understory vegetation. For both trait metrics, we quantified the change in trait-environment relationships when considering the dominant plant functional type (PFT) of the plot. We found that, overall, TWM combined with PFT had the strongest correlations to environmental variables and TWM also had the strongest increase in correlation when adding PFTs. CWM, in contrast, tended to show slightly higher correlations than TWM when not adding PFTs, but the correlations for CWM combined with PFTs were also substantially higher than CWM without PFTs. Overall, we found stronger trait-environment relationships compared to the existing literature. Our findings confirm the relevance of considering PFT-specific trait-environment relationships and demonstrate the considerable impact of different plot-level trait metrics. The choice of the most suitable trait metric depends on the application and the availability of ancillary data that can be used as weighting factors in CWM.
On the Cascade-Dissipation Balance in Astrophysical Plasmas
Authors: Manzini Davide , Sahraoui Fouad , Califano Francesco
Published: March 2024

The differential heating of electrons and ions by turbulence in weakly collisional magnetized plasmas and the scales at which such energy dissipation is most effective are still debated. Using a large data sample measured in the Earth’s magnetosheath by the Magnetospheric Multiscale missionand the coarse-grained energy equations derived from the Vlasov-Maxwell system we find evidence of a balance over two decades in scales between the energy cascade and dissipation rates. The decline of cascade rate at kinetic scales (in contrast with a constant one in the inertial range), is balanced by increasing ion and electron heating rates, estimated via the pressure-strain. Ion scales are found to contribute most effectively to ion heating, while electron heating originates equally from ion and electron scales. These results can potentially impact the current understanding of particle heating in turbulent magnetized plasmas as well as their theoretical and numerical modeling.
Investigating ophiolite weathering via lithium isotopes in the Indo-Burma range of northeast India
Authors: DeFrancesco Giancarlo , McKenzie Ryan , Cheung Chris Tsz Long , Singh Nongmaithem Lakhan , Singh Yengkhom Raghumani , Beaty Brian , Asael Dan , Kaplan Jed Oliver , Planavsky Noah
Published: March 2024

The weathering of silicate minerals regulates climate on million-year timescales. Some silicate bedrock, particularly ophiolites, are more susceptible to enhanced weathering than other lithologies. Lithium isotopes (δ7Li) are a proxy that can be used to help track weathering processes due to the fractionation of Li during secondary clay mineral formation. Here we present data collected from tributaries that source the Nagaland-Manipur Ophiolite Complexes in northeastern India, which ultimately flow into the Irrawaddy River in Myanmar, to test the hypothesis that the weathering of ultramafic terrains generated by arc-continent collisions can drive rapid atmospheric carbon drawdown. Major cations, anions, trace elements, δ7Li, and clay mineralogical compositions were measured from river water, bedload, and suspended sediment to gain insight into silicate weathering processes in the region. Our results show streams and rivers in this region contain δ7Li values that range from 20.6 to 31.2‰, with the ophiolitic-sourced tributaries being heavier than the global riverine average of ~23‰. This indicates that rivers draining ultramafic lithologies in warm humid climates are experiencing higher degrees of weathering intensity than other drainages comprised of more felsic lithologies. Additionally, XRD results show that most river bedload contains smectite clays, which may help promote organic carbon burial. These data combined highlight new pathways toward understanding silicate weathering as it relates to atmospheric CO2 drawdown.
An Improved Model for Estimating the DielectricConstant of Saline Soil in C-Band
Authors: Dong Leilei , Wang Weizhen
Published: March 2024

Soil salinization is one of the major forms of land degradation processes from all over the world. The dielectric constant plays an important role in the process of soil salinity retrieval by using microwave remote sensing. The Dobson model has been widely used to simulate the dielectric constant of nonsaline soil, but the estimated result of the Dobson model did not perform well for saline soil. Moreover, the ions’ concentration is related to soil salinity, and the electrical conductance is a critical factor that influences the imaginary part of the dielectric constant. Therefore, the relationship between them needs to further explore. In addition, saturation is neglected in the current dielectric model of saline soil. In this letter, the relationship between the electrical conductance and ions’ concentration was analyzed based on the experimental data. The saturation as a new parameter was introduced into the Dobson model to improve the estimated accuracy of the dielectric constant of saline soil in the C-band. The comparison between the revised model, the Dobson model, the Hu Qingrong (HQR) model, and the Wu Yueru (WYR) model was presented. The results indicate that there is a significant linear relationship between the electrical conductance and ions’ concentration, with R2 of 0.996, a slope of 0.1456, and an intercept of 0.0252. Once the new parameter is implemented, the improved dielectric model based on the C-band reproduces the dielectric constant of saline soil satisfactorily in each soil sample. The simulated results of the improved model are consistent with the laboratory measurement results, with an RMSE of 0.97 and R2 of 0.953. Compared with other commonly used three dielectric models of the saline soil, the improved dielectric model performs well in simulating the imaginary part of the dielectric constant. The improved agreements between the simulations and the measurements indicate that the revised dielectric model is appropriate for simulating the dielectric constant of saline soil. The revised dielectric model of saline soil will provide a scientific foundation for the soil salinity retrieval from the microwave remote sensing technology.