bluuebunny/crossref_metadata_2025 huggingface dataset:
 In situ Observations of Ultra-Relativistic ElectronAcceleration in the Fastest Heliospheric Shock Wave by Parker Solar Probe
Authors: Krasnoselskikh Vladimir , Jebaraj Immanuel Christopher , Agapitov Oleksiy , Vuorinen Laura , Choi Kyung-Eun , Gedalin Michael , Wijsen Nicolas , Afanasiev Alexandr , Kouloumvakos Athanasios , Mitchell John Grant , Vainio Rami , Hill Matthew , Raouafi Nour
Published: March 2024

Collisionless shock waves (CSWs) in plasma, prevalent in diverse astrophysical contexts, are key to understanding cosmic particle acceleration. These shock waves, observable in environments from heliospheric planetary bow shocks to supernova remnants (SNRs), efficiently convert kinetic energy to thermal energy and accelerate particles to sub-relativistic and relativistic energies. A particular focus is on electrons accelerated by these shocks, as they generate electromagnetic radiation, making astrophysical shocks like SNRs observable. Despite their significance, gaps remain in our understanding of the dynamic mechanisms behind these universal accelerators, underscoring the necessity for in-depth, direct in situ measurements. Heliospheric shocks offer a unique opportunity for such in situ studies, particularly those that are strong and fast, potentially mirroring SNR shocks. This study highlights the groundbreaking in situ observations of the fastest heliospheric shock wave yet, traveling at nearly 1% the speed of light, captured by the pioneering Parker Solar Probe. Positioned just 0.23 astronomical units from the Sun, the probe directly measured the acceleration of electrons and ions to high energies amidst intense electromagnetic activity. A landmark discovery was the acceleration of electrons to ultra-relativistic speeds, with energies reaching up to 6 Million electron volts (MeV). This observation not only provides unprecedented insights into the mechanisms of particle acceleration in CSWs but also bridges the gap in our understanding of similar processes in more distant astrophysical phenomena like SNRs. The findings from the Parker Solar Probe open new avenues for exploring and comprehending the intricate processes of cosmic particle acceleration. 
Impact of Terrain Visibility on Field-Based Landslide Inventories and the Role of r.survey
Authors: Bornaetxea Txomin , Marchesini Ivan , Santangelo Michele , Mondini Alessandro , Fiorucci Federica
Published: March 2024

Landslide inventories form the backbone of numerous natural hazard studies, providing essential data for assessing susceptibility, hazard, and risk. However, the accuracy and comprehensiveness of these inventories are influenced by various factors, including the visibility of the terrain from observation points. This study delves into the critical relationship between terrain visibility and the quality of field-based landslide inventories, with a focus on the implications for hazard analysis.Traditionally, the visibility of a territory has been an overlooked factor, often assumed to be uniform across inventories. However, our research, leveraging the r.survey tool in conjunction with digital elevation models, reveals that the density of landslide information is strongly correlated with visibility. In areas of high visibility, field-based inventories exhibit a higher density of landslide reports, whereas regions with poor visibility are often underrepresented. Conversely, inventories derived from satellite imagery, while consistent, may also lack detailed information, particularly regarding smaller landslides in potentially visible zones, such as areas near roads.The introduction of r.survey, a GRASS GIS plugin, has allowed for an effective visibility assessments. It not only calculates the visibility from various observation points but also incorporates the concept of solid angles to account for the size and orientation of observed objects. This innovative approach enables the development of a 'Size-specific Effective Surveyed Area' (SsESA), refining our understanding of the actual terrain covered during field surveys.Furthermore, our ongoing empirical studies aim to establish a minimum solid angle threshold to determine the visibility of landslides, crucial for improving the accuracy of landslide inventories. Such insights are invaluable for statistical modeling, as biases in inventory data directly influence hazard assessments. By enhancing our understanding of visibility-related biases, we can refine inventory methodologies, ensuring more robust and accurate landslide susceptibility models.In conclusion, terrain visibility significantly impacts the quality and comprehensiveness of field-based landslide inventories. Through the continued development and application of tools like r.survey, we can mitigate visibility-related biases, fostering more reliable hazard assessments and better-informed mitigation strategies.
Is dimethylsulfide a good biomarker?
Authors: Hänni Nora , Altwegg Kathrin , Müller Daniel , Rubin Martin , Wampfler Susanne
Published: March 2024

Sagan et al. (1993) proposed that so-called biomarkers, i.e., unique molecular indicators of life on Earth, could be used to search for extraterrestrial life. This is especially interesting for places that are not reachable for in situ studies and where potential life can only be detected with remote spectroscopical methods, for instance exoplanets. One of the most recent examples that obtained world-wide media coverage is the tentative detection of dimethylsulfide (DMS) in the atmosphere of exoplanet K2-18b with James Webb Space Telescope by Madhusudhan et al. (2023). DMS has been suggested as potential biomarker (Seager et al. 2016) since on Earth this chemical compound is produced by biological activity exclusively and discussed as indicator of life in exoplanetary atmospheres (Madhusudhan et al. 2021). But what if this biomarker is present in the completely abiotic cometary matter? Comets are known to be rich in organic matter that has been well-preserved since the earliest times of our Solar System (Hänni et al. 2022, Hänni et al. 2023), and hence, are a relevant point of reference when it comes to abiotic chemical complexity. We inspected data collected by the high-resolution mass spectrometer DFMS (Balsiger et al. 2007) onboard ESA’s Rosetta spacecraft, which was studying comet 67P/Churyumov-Gerasimenko (hereafter 67P) for two years from up close, for the signature of DMS. Our detailed analysis of the sulfur-bearing hydrocarbon signals detectable in 67P’s coma yields strong evidence for the presence of DMS and thus provides the basis to argue that this molecule might not be a robust indicator of extraterrestrial life.  Sagan et al. Nat. 1993 365(6448):715-721.Madhusudhan et al. ApJ Lett. 2023 956(1):L13.Seager et al. Astrobiology 2016 16(6):465-485.Madhusudhan et al. ApJ 2021 918(1):25.Hänni et al. Nat. Commun. 2022 13:3639.Hänni et al. A & A 2023 678:A22.Balsiger et al. Space Sci. Rev. 2007 128:745-801.
Exploring the impacts of climate change on French hydropower generation
Authors: Baratgin Laure , Polcher Jan , Quirion Philippe , Dumas Patrice
Published: March 2024

Hydropower can play a crucial role in decarbonizing national power mixes, in particular in managing the variability of other renewable energy sources. However, climate change is expected to affect the water resources and could impact hydropower generation.
This study explores the potential impacts of climate change on hydropower generation in France and its broader consequences on the national power system. 
To achieve this, an innovative modeling approach is used, coupling a land surface model driven by outputs of Euro-CORDEX projections and a power system optimization model. The land surface model represents the management of French hydroelectric reservoirs based on the available water resources and the optimal national power dispatch simulated by the power system model. The system takes into account the national regulations on water management.
Our findings indicate that climate change should not have a significant impact on the annual national production of hydroelectric reservoirs, even under extreme scenarios. However, noticeable changes in the seasonality of production due to hydrological changes are found. Production is higher during winter due to higher liquid precipitation, at the expense of spring production due to lower snowmelt. This reduces the need for dispatchable sources in winter and helps to decarbonize the power system. Moreover, we find heterogeneous impacts across regions and the uncertainties in changes in mountain precipitation appear to be a critical factor. Finally, changes in inter-annual variability and drought occurrences and their potential impacts on hydropower are also examined.
Seasonal changes of microbial functions along high-Arctic tundra soil toposequences
Authors: Frossard Aline ,   Climarctic team (Biodiversa ERANET project)
Published: March 2024

High-arctic tundra-soil ecosystems are particularly sensible to global changes due to their proximity to freezing, snow cover, light availability and scarcity of vegetation. Seasonal dynamic are large in these biomes with a very short vegetation growing season. Hydrological fluctuations in these soils are also important, directly impacting the soil biological activity. Yet, little is known on the seasonal dyanmic in the regulation of microbial functions in high-arctic soils and their impact on greenhouses gas exchanges with the atmosphere. Fluxes of greenhouse gases (CO2, CH4 and N2O) and microbial functions linked to C and N cylcing were assessed at each season along a slope toposequence in high-arctic tundra soils near Ny-Ålesund (Svalbard) and compared with prokaryotic and fungal community structures. Microbial functional diversity exhibited strong seasonal patterns, with most microbial functions acquiring C, N and P enhanced in summer, at the peak of the plant growing season. Seasonal dynamics was also evident for greenhouse gas fluxes but were not consistent across seasons. While CO2 fluxes were clearly increased in summer, CH4 fluxes were slightly higher in Autumn, especially in the upslope soils, alike methanogenesis gene abundance mcrA which distinctly increased in both biocrust and soil layer of the upslope site in Autumn. N2O gas fluxes were clearly higher in both shoulder seasons (i.e. Spring and Autumn), when freeze-thaw cycle are frequents. Seasonal microbial functional changes however did not mirror the prokaryotic and fungal community structure, which were more influenced by the microtopography and the soil depth layers (biocrust vs underneath mineral soil). These findings highlight the intricate relationships between microbial functions, diversity, and environmental factors in high-Arctic soils and underscore the importance of considering both seasonal and microtopography factors in understanding soil microbial dynamics in Arctic ecosystems.
Climate effects of contrail cirrus for aircraft with hydrogen combustion   
Authors: Pettersson Susanne , Johansson Daniel
Published: March 2024

Aviation accounts for approximately 5% of the current anthropogenic climate impact. Up to two thirds of the warming generated by airplanes is attributed to non-CO2 effects with contrail cirrus as the largest contributor. Hydrogen as aviation fuel promises zero carbon emission but the non-CO2 effects of this new fuel are poorly known.In this study we investigate the generation of contrail cirrus from hydrogen combustion using a modified version of the Contrail Cirrus Prediction model (CoCip). In the absence of soot-emissions ice particles in hydrogen contrail are assumed to form on entrained aerosols, ultrafine volatile particles and lubrication oil. The calculation of the number of ice particles formed on entrained aerosols is approximated by previously published simulation results and theory.  Ultrafine volatile particles and lubrication oil both activate into water droplets at lower temperatures than soot and aerosols due to the Kelvin effect (small radius) and hydrophobicity respectively and are implemented using theory and published experimental results.Using hydrogen fuel contrails can, according to the Schmidt-Appleman criteria, form at lower altitudes than with jet fuel due to the increase in water vapor in the exhaust. Despite this our preliminary results show an overall decrease in both warming and cooling contrails for hydrogen compared to standard jet fuel. We do find that hydrogen contrails can generate more radiative forcing than jet contrails at very low temperatures mainly due to the activation of lubrication oil in combination with the larger amount of water vapor. For the bulk of flights however, hydrogen fuel leads to either equal or less contrail radiative forcing than jet fuel even with reduced soot-emissions in line with lean-burn engines.   
Modelling heterogeneity of land surface waters in the permafrost region
Authors: Kleinen Thomas , de Vrese Philipp , Stacke Tobias , Brovkin Victor
Published: March 2024

When considering high latitude regions, one of the striking characteristics is the abundance of surface water in comparison to lower latitudes. This difference is not just limited to the total area covered by surface water, but it also extends to the size distribution of water bodies: While surface water in lower latitudes most often occurs in the form of larger lakes or rivers, high latitude regions often display a wide variety of surface water features, ranging from small puddles to huge lakes. Considering the climatic and carbon cycle consequences of lower latitude large water bodies in land models is relatively straightforward – they can be considered static, be prescribed from observations, and described using dedicated submodels. However, considering surface water in the high latitudes comprehensively is substantially more challenging, as a much larger range of sizes needs to be considered, parts of which will not be available from observations. Furthermore, due to the dynamics of permafrost, these cannot be considered static any more and need to be treated dynamically.To better represent high latitude regions in the ICON-Land land surface model, part of the ICON-ESM Earth System Modelling framework, we are developing a representation of multiple scales of water bodies, ranging from large lakes to small puddles, as well as areas of water-saturated soil. The smaller-scale features are of particular interest, as they do not just affect the exchange of water and energy between surface and atmosphere, but also have large impacts on the carbon cycle and methane emissions. To do this, we employ a statistical distribution function of water body sizes, allowing us to obtain energy, water, carbon and methane fluxes for water features of all sizes.We will present our novel modelling framework and show first results covering selected Arctic locations.
Hydrothermal alteration shifting brittle-ductile transition promotes volcanic flank collapses
Authors: Niclaes Jens , Delmelle Pierre , Rattez Hadrien
Published: March 2024

Volcanoes are inherently unstable, causing tremendous catastrophes, such as cities destruction or large tsunamis creation. These large flank collapses are not one-time events, it happens cyclically over the life of a volcano. One of the potential causes of such phenomena is hydrothermal alteration: Reactive fluids coexisting with a heat source interact with the host rocks and modify their mechanical properties. In most volcanoes, these hydrothermal alterations have a negative impact on the brittle-ductile transition of volcanic rocks, promoting a ductile failure behavior instead of a brittle one. However, the mechanisms behind large volcanic flank collapse are still obscure, especially when hydrothermal alteration is involved. The influence of the transition of mechanical behavior is rarely considered when the stability of the volcano is assessed. We performed Finite Element Method simulations, in dry and wet conditions, on 2D and 3D geometries of the Tutupaca volcano before its collapse at the end of the 18th century. To assess the stability, the strength reduction method was applied for each configuration allowing the obtention of the factor of safety and the most critical failure mechanism. The collapse is best reproduced when the volcanic rocks are modeled as a Mohr-Coulomb material with a compressive cap. The cap offers the consideration of the low brittle-ductile transition observed in previous experimental studies of altered volcanic rocks. Our results demonstrate that hydrothermal alteration influences the stability of a volcano through the brittle-ductile transition variation. These results are an entry point into assessing the instabilities of volcanoes because of hydrothermal alteration. They consider silicic and argillic alterations, but many others exist, and they might alter the rocks in a different way than reducing the brittle-ductile transition. These preliminary results are a basis to start adding complexity with, for example, external events such as earthquakes or meteorologic changes. 
Investigating electrical polarization signatures of sugar beet and maize: A field study using spectral electrical impedance tomography
Authors: Michels Valentin , Weigand Maximilian , Kemna Andreas
Published: March 2024

Despite their vital role for agricultural management practices and plant breeding experiments, it is still challenging to characterize plant roots non-invasively in their natural environment. A promising new method for plant root characterization is the spectral electrical impedance tomography (sEIT) method, which is able to image the conductive and polarizable subsurface properties with high spatio-temporal resolution. Electrical polarization signatures have been shown to be sensitive to root structure and activity, although superimposed soil signatures complicate the interpretation. Recent studies have demonstrated that impedance measurements can be used to estimate root traits under laboratory conditions, especially in hydroponic experiments. However, field studies using sEIT on plant-root systems are still scarce.In this study we present a field dataset of multi-frequency sEIT measurements on sugar beet and maize. Three different growth stages were measured during a whole growing season. We performed complex resistivity inversions for each measurement frequency, and subsequently analyzed the spatially resolved spectral response using a Debye decomposition analysis. Characteristic relaxation times, extracted from the spectral analysis, serve as proxies indicating the length scales of the observed polarization processes. We find that the physiologically different plant root systems cause distinct polarization responses in the low-frequency range. While both root systems exhibit an increasing polarization response towards higher frequencies, sugar beet develops an additional low-frequency polarization peak near 10 Hz later in the season, corrseponding with increasing size of the sugar beets. We attribute this peak to the polarization of root structures associated with the macroscopic dimensions of the beet roots, and demonstrate this link through the correlation of the retrieved mean relaxation time at the sugar beet positions with the square of the respective maximum beet diameter. Additionally, we evaluate the intrinsic spectral form of the polarization signatures extracted from the maize root area, and find a moderate correlation with the fresh biomass.In conclusion, our results highlight that sEIT can be used in the field for plant root trait estimations, but structurally differing plants require different analysis procedures to extract root information. Additionally, environmental factors, like a varying soil composition or soil water content, have a strong influence on the measured impedance signal, and can make precise root trait estimation difficult.
Understanding the Thermal Properties of Fast CMEs by Integrating White-light Observations and Analytical Modeling
Authors: Khuntia Soumyaranjan , Mishra Wageesh
Published: March 2024

Coronal Mass Ejections (CMEs), huge magnetized plasma erupting from the Sun, pose potential risks to space weather and space-based infrastructure. While extensive research has focused on examining the kinematics of CMEs, there has been limited study of their thermodynamic evolution, particularly at specific heliocentric distances closer to the Sun. Acknowledging that variations in internal plasma properties can impact the overall evolution of CMEs and vice versa is crucial. This study investigates diverse kinematic profiles and associated thermodynamic changes in nine fast CMEs at coronal heights where measuring thermodynamics is challenging. We estimated the distance-dependent evolution of various internal parameters, including polytropic index, temperature, heating rate, pressure, and internal forces driving CME expansion by leveraging the improved Flux Rope Internal State (FRIS) model. The FRIS model utilizes the 3D kinematics derived from the Graduated Cylindrical Shell (GCS) model as input. Our findings reveal that CMEs can maintain their temperature above the adiabatic cooling threshold despite expansion, progressing towards an isothermal state during later propagation phases. The fast CMEs maintaining higher expansion speeds exhibit less pronounced temperature decreases. We found that CME's expansion speed and acceleration correlate well with its maximum temperature drop to reach the isothermal state. Multi-wavelength observations of flux ropes at the source region support the FRIS model-derived results at lower coronal heights. Our analysis elucidates that the primary forces influencing CME radial expansion are the centrifugal and thermal pressure forces, while the Lorentz force acts as a constraining factor. Notably, the thermal pressure force governs expansion at higher heights and is solely responsible for radial expansion. This study enhances our comprehension of the thermodynamic properties of fast CMEs, offering valuable insights for refining assumptions of the polytropic index value in different magnetohydrodynamics (MHD) models to improve the prediction of CME properties at 1 AU.
Exploring extreme environments at the Arctic seafloor: comprehensive studies integrating science, sustainability, and responsible resource exploitation 
Authors: Panieri Giuliana , Argentino Claudio , Savini Alessandra , Fallati Luca , Ramirez Llodra Eva
Published: March 2024

The Arctic seafloor has emerged as a pivotal asset, playing a crucial role in fostering intensified exploitation activities and the incoming deep-sea mining industry, particularly in the so-called "extreme environments" where deep-sourced fluids reach the seafloor at hydrothermal vents and hydrocarbon seeps. Positioned as a promising frontier for resource extraction, exploring the Arctic seafloor is significant with the expanding reach of human exploitation. The ongoing reduction in sea ice coverage in the Arctic region facilitates resource exploration and opens up previously inaccessible areas for scientific investigation.The paramount importance of comprehending the unique geological and ecological characteristics of the Arctic seafloor becomes evident in the quest for sustainable and responsible exploitation. As a response to this imperative, the integration of seafloor optical and acoustic seafloor and sub-seafloor imaging, and bio-geochemical analyses represents a pivotal approach. This integration allows the reconstruction of comprehensive models delineating geological processes, including the dynamics of hydrothermal and hydrocarbon systems.This presentation aims to show the effectiveness of a multidisciplinary and multiscale approach in exploring extreme environments through a selection of case studies. Encompassing remote sensing, geochemistry, biology, and a range of seafloor imaging techniques, these studies highlight the complexity and unicity of these environments. Furthermore, we will show how those integrated studies equip both the public and policymakers with essential information, fostering a balanced approach that reconciles economic interests with environmental conservation in the realm of Arctic seafloor exploration.
Building probabilistic projections of the Antarctic contribution to global sea level rise using a random forests emulato
Authors: Turner Fiona , Rougier Jonathan , Edwards Tamsin , Coulon Violaine , Klose Ann Kristin
Published: March 2024

In order to predict future global sea level rise, it is key for us to have better understanding of the changes in the cryosphere, as is being done in the PROTECT project (https://protect-slr.eu). Large uncertainties exist around how these changes will present over the coming centuries, with the Antarctic ice sheet being the most uncertain component with regards to predicted mass changes. It is therefore necessary to turn to statistical techniques to create more robust predictions.
Here, we present results from a random forests emulator simultaneously trained on two ice sheet models, Kori and PISM, forced by four global climate models. We emulate the relationship between inputs, namely climate change and ice sheet model settings, and an output, sea level contribution. The use of random forests allows us to improve on previous Gaussian Process emulators (Edwards et al., 2021) in speed and the treatment of factor inputs. We also transform the multi-centennial output in order to allow us to model the whole time series, rather than each year individually. The emulator allows us to interpolate (and extrapolate slightly) in order to build probabilistic projections of sea level contribution to 2300 that include climate and ice sheet modelling uncertainties under all five Shared Socioeconomic Pathways (SSPs), despite only two being used in the ensemble of simulations.
References
Edwards, T. L., Nowicki, S., Marzeion, B., Hock, R., Goelzer, H., Seroussi, H., Jourdain, N. C., Slater, D. A., Turner, F. E., Smith, C. J., et al. (2021). Projected land ice contributions to twenty-first-century sea level rise. Nature, 593(7857):74–82.
Assessing the Structural Stability of Thwaites Eastern Ice Shelf and Its Influence on the Future Evolution of Thwaites Glacier
Authors: Wild Christian , Pettit Erin , Alley Karen , Truffer Martin , Scambos Ted , Heywood Karen , Muto Atsuhiro , Hall Rob , Sharp Meghan , Smith Haylee , Carroll Georgia , Wanzer Lucy , Trunz Celia , Wahlin Anna , Collao-Barrios Gabriela , Maclennan Michelle , Ochwat Naomi , Dotto Tiago , Luckman Adrian , Kachuck Samuel ,   TARSAN team
Published: March 2024

The Thwaites Eastern Ice Shelf stands as the last remaining floating extent of the consequential Thwaites Glacier in West Antarctica. In the past, it has provided buttressing of the grounded glacier ice, but in the last decade the ice shelf has undergone significant weakening that has reduced its ability to buttress the glacier. Important signs of weakening include: 1) the ice flow measured by ground-based GPS shows continuous acceleration, nearly doubling in speed from 1.65 m/d in 2019 to 2.85 m/d by early 2023; 2) a recent breakout of sea ice has accelerated retreat at the western calving front of the Eastern Ice Shelf; 3) increased damage in a confined shear zone along the north-western pinning point has effectively separated the ice shelf from this pinning point.; 4) five rifts formed since 2016 and have propagated episodically into the center of the most coherent section of the shelf; and 5) several full thickness “gashes” have opened and continue to open parallel to and just downstream of the grounding zone to accommodate the recent ice-shelf speed up through localized strain. Due to these full-depth rifts, the ice shelf has nearly entirely detached from the upstream grounded ice, and is now functioning as a relatively thin, floating ice plate that provides minimal support to the grounded sections of Thwaites Glacier. This accumulation of damage in the ice shelf is happening during a period in which we observe  suppressed basal melt rates and little measurable thinning, suggesting that melt is not the primary driver of ongoing changes. Here, we present the most up-to-date synthesis assessment of the structural integrity of this ice shelf, as well as its relation to ocean conditions underneath and the pinning point, and consider the stability of the ice shelf within the context of ice flow off the continent and projections for sea-level rise.
Vertical transport of microplastics from agricultural mulching films and associated chemical additives in soil ecosystems 
Authors: Hurley Rachel , Consolaro Chiara , van Loon Sam , Tsagkaris Aristeidis , Dvorakova Darina , de Jeu Lotte , J. Zantis Laura , A.M. van Gestel Cornelis , Nizzetto Luca
Published: March 2024

Agricultural soils receive substantial inputs of microplastic pollution from a range of different sources. The degradation and fragmentation of mulching films during and after use is expected to represent an important source of microplastic particles to soils, backed up by emerging evidence from monitoring activities. Yet, the transport and fate of these particles after they enter soil environments remains a persistent knowledge gap. This is important as soils may effectively retain these particles – resulting in increasing pollution with successive inputs – or particles may be mobilised from soils, contaminating other environments such as groundwater or surface waters. The processes that control retention versus export of particles have been poorly constrained and are expected to be complex. Chemical additives are routinely added to plastic mulching films to bestow a range of specific material properties. The extent to which these chemicals may leach out of particles in soil environments, and their potential to be transformed or mobilised in soils following release is not well known.This study tracked the vertical transport of microplastic fragments derived from two relevant mulching films and associated chemical additives within soils: one biodegradable mulching film and one conventional plastic mulching film. The study specifically investigated the influence of factors expected to exert a control on particle/chemical fate: bioturbation and soil water inputs. The experiment was conducted in the CLIMECS (CLImatic Manipulation of ECosystem Samples) facility at Vrije Universiteit Amsterdam, which comprises 40 soil columns that simulate ecosystems – with soil, vegetation, and fauna – and are individually controlled for different environmental conditions. The two types of microplastic fragments were added to the upper layer (10 cm) of soil columns (total length: 40 cm) to represent a contaminated plough layer. Different treatments consisted of high and low microplastic concentrations, high and low watering regimes, and the presence and absence of earthworms. The columns were maintained for a period of twelve weeks. Microplastic and chemical additives content was measured in six different depths within each core at the end of the three months, to assess the extent of vertical transport. The results from this study reveal important insights on the mobility of mulching film fragments within soil systems and elucidate some of the important controls on particle movement. This provides crucial context related to the exposure of soil environments to soil microplastic and chemical additive pollution derived from mulching film use.
Electron velocity-space scattering from whistler waves in the Earth’s magnetosheath
Authors: Svenningsson Ida , Yordanova Emiliya , Khotyaintsev Yuri V. , André Mats , Cozzani Giulia
Published: March 2024

Whistler waves are found in various space plasma environments, such as the Earth’s magnetosheath, where they affect particle dynamics and energy transfer. Through wave-particle interactions, they contribute to changes in both the energy and pitch angle of electrons. However, the significance of whistler waves in different plasma regions is not fully known.In this work, we use MMS measurements to calculate the occurrence and properties of whistler waves in the Earth’s magnetosheath. Based on selected MMS orbits, we compare the plasma conditions offered by the more stationary quasi-perpendicular (Q⊥) to the more fluctuating quasi-parallel (Q॥) magnetosheath. We show that the whistler waves occur in local magnetic dips and density peaks and are not necessarily correlated with electron temperature anisotropy. Also, there is an elevated occurrence downstream of Q⊥ shocks, compared to the Q॥ configuration. Further, by calculating pitch-angle diffusion coefficients, we find that whistler waves can significantly reshape the electron velocity distribution during the time a plasma parcel spends in the magnetosheath, which has important implications for the plasma dynamics of the magnetosheath region.
Using Remote Sensing to Inform Valuation of Urban Treescapes in the UK Beyond Hard Ecosystem Service Provision
Authors: Fennell Joseph , Walker Hannah , Maseyk Kadmiel , Doick Kieron , Wheeler Philip
Published: March 2024

Urban trees provide a range of environmental, aesthetic, recreational and cultural benefits, and in some cases, disbenefits. This poses a challenge in capturing and representing the various human values associated with them. The Branching Out project seeks to develop a valuation approach for trees in the urban environment that incorporates cultural and social values of the wider community. The project focuses on the task of assigning value to tree assets at scale, incorporating the diverse and subjective perspectives that communities hold. The study develops methodologies that account for the ways in which individuals and communities perceive, appreciate, and derive value from urban trees, ultimately contributing to more comprehensive and inclusive approaches to urban tree valuation.
To provide valuation at scale, a remote sensing methodology was developed, using 30cm aerial hyperspectral and 7cm resolution broadband imaging data. These data were captured over three target cities in the UK (York, Cardiff and Milton Keynes), representing a range of urban landscapes from historic city (York) to 20th Century `Garden City’ (Milton Keynes). A targeted sampling approach was used to complete ground biophysical surveys of all trees within 1 ha quadrats across each of the cities. Qualitative data from citizen and end-user panels were collected across all cities over a series of workshops. These workshops captured a wide range of value indicators that were assigned to biophysical indicators by the project team.
In this presentation we demonstrate a novel, hybrid Deep Learning method for processing gridded imaging data and existing map datasets into rich individual tree datasets that support different downstream valuation methodologies. We present a software pipeline built on Open Source tools to facilitate this, along with a set of example valuation use-cases.
This project will inform urban planners, policymakers, and communities about the cultural and social benefits of urban treescapes and provide a blueprint for future city-scale valuation. By combining remote sensing with cultural and social valuation, this research contributes to the development of evidence-based strategies for sustainable urban planning, emphasising the importance of preserving and enhancing green spaces of the UK.
Tropospheric Parameters Derived From Co-located Instrumentation at the Onsala Space Observatory
Authors: Haas Rüdiger , Elgered Gunnar
Published: March 2024

Observations performed with ground-based space geodetic and remote sensing techniques are sensitive to the amount of water vapour in the neutral atmosphere. Corresponding parameters that describe the signal delay in the troposphere can be derived for example from the analysis of data collected from geodetic Very Long Baseline Interferometry (VLBI), Global Navigation Satellite System (GNSS), as well as microwave radiometers. The latter instruments are often referred to as water vapour radiometers (WVR).The Onsala Space Observatory (OSO) operates a number of such instruments for VLBI, GNSS and WVR measurements, all co-located within about 600 m. Among these are the Onsala twin telescopes (OTT), two modern 13.2~m diameter radio telescopes performing observations in the VLBI Global Observing System (VGOS) of the International VLBI Service for Geodesy and Astrometry (IVS). The OTT are the first operational VGOS twin telescopes worldwide and are contributing with observations to the IVS since 2019. OSO also operates eight permanently installed GNSS stations, of which two are official stations in the International GNSS Service (IGS) network. Furthermore, OSO operates ground-based microwave radiometers, which are used for atmospheric research and perform continuous observations of the water vapour content in the neutral atmosphere. Data analysis of all three techniques, VLBI, GNSS and WVR, allows to derive information on the temporal and spatial variations of water vapour in the neutral atmosphere. Using co-located instrumentation within a few hundred metres distance thus offers a perfect opportunity for comparisons and assessments of the results.We focus on data recorded at OSO during 2022 and compare the parameters describing the signal delay in the neutral atmosphere, i.e. the so-called equivalent zenith total delays and the linear horizontal delay gradients. The temporal resolution of the derived parameters is 15 min or less. Out of more than 40 VGOS experiments in 2022, each of a duration of 24 h, we have WVR data covering at least half of the session in all except one.  We have examples where the equivalent zenith wet delay only varies by 2--3 cm over an experiment during rather stable atmospheres.  When the atmosphere is more variable the zenith wet delay can vary by more than 10 cm over 24 h.
Processes involved in the formation of extreme seasons – an important research theme at the weather and climate interface
Authors: Wernli Heini , Röthlisberger Matthias , Binder Hanin , Boettcher Maxi , Hartmuth Katharina , Hermann Mauro
Published: March 2024

Meteorological extremes on the seasonal time scale have received increased attention due to their relevance for society and economy. In the five-year project INTEXseas, we developed an approach to identify spatially coherent extreme season objects according to specific metrics, for instance extremely wet winters, cold winters, or hot and dry summers with an extreme seasonal-mean vapour pressure deficit (VPD). The approach has been applied to ERA5 reanalyses and large ensemble CESM climate simulations under an RCP8.5 emission scenario. This presentation will first set out the motivation for studying extreme seasons, highlight their potential impacts, and introduce our identification approach. We then sketch three illustrative examples of investigating meteorological processes involved in the formation of extreme seasons. The examples address (i) cyclone characteristics associated with extreme wet seasons, (ii) sea surface temperature anomalies potentially related to extremely cold winters downstream, and (iii) a quantitative analysis of the contributions of temperature and atmospheric moisture anomalies for very rare summer VPD extremes and their increase in a future climate. These examples should showcase the diversity of processes and impacts associated with extreme seasons, and the need for intensified research about the physical understanding of this type of high impact events at the interface of weather and climate.
Impact modeling with Bayesian inference for crop yield assessment and prediction
Authors: Vlachopoulos Odysseas , Luther Niklas , Ceglar Andrej , Toreti Andrea , Xoplaki Elena
Published: March 2024

It is common knowledge that climate variability and change have a profound impact on crop production. From the principle that “it is green and it grows” to the assessment of the actual impacts of major weather drivers and their extremes on crop growth through the adoption of agro-management strategies informed by tailored and effective climate services, there is a well documented scientific and operational gap. This work focuses on the development, implementation and testing of an AI-based methodology that aims to reproduce a crop growth model informing on grain maize yield in the European domain. A surrogate AI model based on Bayesian deep learning and inference is compared for its efficiency against the process-based deterministic ECroPS model developed by the Joint Research Centre of the European Commission. The rationale behind this effort is that such mechanistic crop models rely on multiple input meteorological variables and are relatively costly in terms of computing resources and time, crucial aspects for a scalable and widely adopted solution. Such approaches make it possible to run very large ensembles of simulations based, for instance, on ensembles of climate predictions and projections and/or a perturbed parametrization (e.g. on the atmospheric CO2 concentration effects). Our surrogate crop model relies on three weather input variables: daily minimum and maximum temperatures and daily precipitation, where the training was performed with the ECMWF-ERA5 reanalysis. 
Testing a PICO quadratic sub-shelf basal melt module in the GRISLI ice sheet model
Authors: Menthon Maxence , Bakker Pepijn , Quiquet Aurélien , Roche Didier
Published: March 2024

The Antarctic ice sheet dynamics is primarily driven by basal melting under the ice shelves. The limitation of computational resources forces the usage of simplified parametrizations in ice-sheet models. Multiple parametrizations have been developed and implemented over the last years (Reese et al. 2018, Lazeroms et al. 2018, Pelle et al. 2019, Jourdain et al. 2020, etc.). The PICO module (Reese et al. 2018) demonstrates to be a good trade-off between complexity and computational resources for paleo ice-sheet reconstructions. Lately, Burgard et al. 2022 suggested that the implementation of a quadratic version of the PICO module could improve it significantly.Here we test the implementation of the PICO module with a quadratic relationship between the thermal forcing and the melt in the GRISLI ice sheet model. We test a wide range of parameter values to calibrate the module, we compare the quadratic version of the module with the original version, under 2 different resolutions. Eventually, we show the results of simulations on paleo and future applications.
Thunderstorm Ground Enhancement (TGE) Signatures in the Eastern Mediterranean Using Gamma Ray and Atmospheric Electricity Measurements
Authors: Mauda Nadav , Yair Yoav , Price Colin , Reuveni Yuval
Published: March 2024

Intense electric fields within thunderclouds can lead to increased flows of high energetic electrons, resulting in the generation of gamma rays and neutrons. This can be manifested as Thunderstorm Ground Enhancement (TGE), an abrupt enhancement of detectable surface particle count rates which are correlated with thunderstorm activity. This research aims to conduct a comprehensive investigation of gamma ray enhancement unrelated to Radon rainout or washout effects. We utilize lightning data from both World Wide Lightning Location Network (WWLLN) and Earth Networks Total Lightning Network (ENTLN), along with gamma ray, vertical electric field, and other atmospheric parameter measurements. Our analysis include two continuous suspected TGE events within close range (< 20 km radius) to our measurement site, which are then divided into several sub-temporal events for a more detailed analysis. Our initial analysis reveals a significant increase in gamma ray count rate, accompanied by fluctuations in the atmospheric electric field during thunderstorm activity. Interestingly, some of these fluctuations occur without any lightning throughout the course of the event. We propose several physical mechanisms based on the lower atmospheric conditions combined with our gamma ray and vertical electric field measurements. The study assesses the impact of these mechanisms and evaluates the practicality of the proposed approach.
Tracing the eutrophication history of Lake Baldegg using diatom-bound nitrogen isotopes
Authors: Millet Jules , Dubois Nathalie , Lehmann Moritz F. , Studer Anja S.
Published: March 2024

Diatom frustules are well-preserved in marine and lacustrine sediments over hundreds or even thousands of years. In addition, although only in very small amounts, they also contain organic matter within their siliceous structure. Previous applications have shown that the 15N/14N ratio of the organic nitrogen contained in diatom frustules (diatom-bound δ15N, or δ15NDB) can be used as a proxy for nutrient cycling in the polar oceans, and that it is not affected by diagenetic effects. However, the applicability of this paleo-proxy to lacustrine sediments has never been tested. Here, we explore the use of δ15NDB to reconstruct the history of nitrogen dynamics in Lake Baldegg (Switzerland) over the past 300 years. This lake was heavily eutrophied due to anthropogenic activities during the 20th century, before the implementation of lake restoration measures (i.e., artificial aeration of the lake bottom since 1982). Using a multi-proxy approach (e.g., reflectance-inferred chlorophyll a and organic carbon accumulation rates, XRF sulfur counts, bulk isotopic composition, C:N ratio), we identified two distinct eutrophication phases (1880-1950 and 1950-1980) that were characterised by an increase in organic matter accumulation and primary productivity, the occurrence of bottom water anoxia, and a change in the origin of the bulk organic matter. The implementation of re-oligotrophication measures has led to the disappearance of anoxic conditions at the bottom of the lake after 1995, and a decrease in phosphorus concentrations in the lake (the latter observed in the monitoring data), which seems to have mitigated primary productivity and organic matter accumulation. δ15NDB increased during the first phase of eutrophication, which could be due to extended denitrification in the water column in an expanding anoxic water column zone, and/or limiting N concentrations for phytoplankton growth, leading to increased nitrate utilization. During the second phase, δ15NDB decreased, probably because fixed N in surface waters was no longer limiting for phytoplankton. After the implementation of re-oligotrophication measures, δ15NDB increased again, possibly the isotopic imprint of external N inputs with a high δ15N signature, such as organic fertilizers (e.g. animal manure, compost). Additionally, the δ15N of hand-picked Daphnia ephippia are lower than, and show no consistent offset to, δ15NDB, suggesting that the N isotope signal of δ15NDB is not transferred to the upper trophic level in that lake. Finally, we measured the offset between δ15NDB and δ15NBULK providing insight into the effects of early diagenesis on the N isotopic composition of bulk sediments. In Lake Baldegg, the offset reversed after the lake was artificially oxygenated, indicating a role of sediment oxygenation in the diagenetic alteration on δ15NBULK.
Assessing the potential of TROPOMI measurements to improve regional methane emission estimates over India
Authors: Mathew Thara Anna , Pillai Dhanyalekshmi K , Deshpande Monish V , Thilakan Vishnu , Kanakkassery Sanjid Backer
Published: March 2024

Methane is emitted by several anthropogenic source sectors, including livestock, oil and gas systems, coal mining, landfills, wastewater treatment, rice cultivation and natural sources such as wetlands. The short lifetime and considerable global warming potential make methane an immediate target for reducing global warming. The existing bottom-up methods relate emissions to source region activities, but significant uncertainties exist when emissions are derived at regional or local scales. In this context, satellite observations of atmospheric methane concentrations can be helpful for improving the inventory information by using additional constraints from atmospheric distributions. In the present study, we use the column-averaged dry-air mixing ratio of methane (XCH4) from  TROPOMI (Tropospheric Monitoring Instrument) on the ESA Copernicus Sentinel-5 Precursor satellite to infer India’s CH4 emissions. We establish the potential of these retrievals to quantify methane emission hotspots and to improve the emission estimates over the Indian subcontinent. The Eulerian model Weather Research Forecast (WRF) coupled with Chemistry (WRF-Chem-GHG) simulations has been used for the forward  transport simulations of atmospheric methane. The inversion studies introduced will enable us to improve the existing anthropogenic emission estimates available in the Indian region.