bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysing the sensitivity of Sentinel-1 SAR to vegetation water dynamics using a combined model approach
Authors: Kranz Johanna , Forkel Matthias , Bernhofer Christian , Mauder Matthias , Queck Ronald
Published: February 2023

Changes in plant phenology as for example earlier leaf unfolding and delayed autumn senescence can result in variations in the carbon and water cycle. Studies investigating the impact of phenological shifts on biophysical processes such as water availability are still limited. Due to the sensitivity of radar satellite observations to both, structural and dielectric properties of the scattering materials, microwave remote sensing offers the potential to analyse structural (i.e. canopy biomass) and physiological (i.e. water status) dynamics in vegetation.Here, we aim to derive annual water dynamics of vegetation canopies from the Sentinel-1 C-band radar backscatter signal by removing the influence of vegetation structure on the backscatter seasonality. To decouple the phenology of vegetation structure from the moisture content dynamics, a semi-empirical backscattering model (Water Cloud Model, WCM) is combined with a canopy water balance model. The WCM aims to separate contributions of soil and vegetation to the total backscatter. When introducing physical parameters for vegetation structure like leaf area index (LAI) and and moisture like leaf fresh moisture content (LFMC) to describe the vegetation backscatter, the effect of the seasonal variability of both variables on the radar signal can be assessed. The canopy water balance model estimates interception and changes in the canopy saturation and storage capacity of the vegetation using precipitation and throughfall measurements. Both models are combined to iteratively estimate measures of vegetation moisture. To calibrate the two models, we use measurements of LFMC and of canopy interception for the Tharandt ecosystem site in Germany in 2022, which is part of the ICOS and FLUXNET network. The calibrated model is then used to analyse the individual effects of both vegetation descriptors, LAI and LFMC, by fixing either one and looking at the changes in the seasonality of the S1 signal. The combined use of both models will allow to remove the structural-related changes in the Sentinel-1 radar backscatter to finally retrieve vegetation water dynamics over larger areas.
Investigation of rainfall precursors using in-situ and remote sensing techniques in the southeast of the Iberian Peninsula
Authors: Navas Guzmán Francisco , Wang Wenyue , Hocke Klemens , Nania Leonardo , Cazorla Alberto , Titos Gloria , Matthey Renaud , Alados Arboledas Lucas
Published: February 2023

Rainfall prediction is one of the most challenging and uncertain tasks in weather forecasting, which has a significant impact on human society. Detection of heavy rainfall trends may be masked or amplified by natural variability, and numerical weather prediction (NWP) models have difficulty to predict them accurately. Therefore, understanding of rainfall effects with the evolution of atmospheric parameters and seeking atmospheric precursors of rainfall for nowcasting or prediction become an urgent need.To date, most related studies have analyzed only a limited number of rain events or lacked long-term observations. This is likely to have a weak robustness. A multi-instrument and multi-parameter atmospheric monitoring system to detect precipitation precursors can improve the existing nowcasting system. AGORA (Andalusian Global ObseRvatory of the Atmosphere) is an ACTRIS facility located in the southeast of the Iberian Peninsula which offers unique infrastructure for the study of aerosol, clouds and precipitation. AGORA consists of two stations, an urban station located in the city of Granada (680 m asl) and a high-mountain station located in the National Park of Sierra Nevada (2580 m asl), separated by a horizontal distance of 20 km only. This infrastructure comprises state-of-the-art instrumentation covering active and passive remote sensing and in-situ techniques, including lidars, cloud radars, microwave radiometer, and weather stations. These instruments can obtain multiple atmospheric parameters (atmospheric water, aerosol, temperature, wind, etc.), including their vertical profiles.In this study, we investigate the potential of different atmospheric parameters from ground-based microwave radiometer, ceilometer, nephelometer, absorption photometer and weather stations for the nowcasting of rainfall. We use 694 rain events identified by microwave radiometer in the southeast of Iberian Peninsula to identify conditions favorable to trigger rainfall over 10 years, and to analyze how they are related to observed changes in water vapor and aerosol load and properties. The composite analysis is carried out in a long time interval of 8 hours before and 16 hours after rain, with the onset of rain serving as the time marker for this method. The aim of our study is to show the typical behavior of rainfall, to reveal the interaction of rainfall with atmospheric parameters, and to explore the precursors of rainfall.
Potential of optical sensors for polymer type identification in e-waste recycling streams
Authors: de Lima Ribeiro Andréa , Fuchs Margret , Röder Christian , Schüler Nadine , Lorenz Sandra , Sheng Yang Xiao , Heitmann Johannes , Dornich Kay , Gloaguen Richard
Published: February 2023

Plastics are major components of waste from electrical and electronic equipment (WEEE, or e-waste) accounting for up to 25% of annual e-waste production. The composition of such plastics varies greatly according to their original function in the electrical and electronic equipment, and may include additives such as dark pigments and brominated compounds. With WEEE becoming the fastest growing waste stream in recent years, the recycling of polymers became a keystone for waste management and closing material loops. Closing the loops in material life cycles requires that type-pure plastics are obtained at the end of the recycling chain. Accordingly, the identification of polymers prior to their sorting in recycling lines is a fundamental prerequisite.Here, we explore how an innovative combination of optical sensors can aid the identification of plastics in the plastic recycling environment in order to increase recovery rates and quality of recyclates.We have selected 23 different polymer samples, representative of the plastic types commonly found in e-waste. We investigated the sequential use of high-speed hyperspectral imaging (HSI) and Raman spectroscopic sensors for digitalization of the waste stream and identification of polymer composition. HSI-reflectance sensors in the short-wave infrared (HSI-SWIR, Specim AisaFenix, 970 - 2500 nm) domain acquired simultaneously spatial and spectral information, allowing for mapping and initial identification of certain transparent and light-coloured polymers (PE, PP, PET, and PC). Raman measurements, collected at specific points and with integration times < 2 seconds, allowed for specific identification of all polymer samples, including black plastics. The use of both sensor technologies on conveyor belts has the potential to fully characterise the WEEE plastics stream, generating identification signals serving as input for sorting machines or simulation models. The combination of latest high-speed sensors and data processing opens many further fields of material stream characterisation and monitoring, which come with high data acquisition rates and volumes. Consequently, a smart selection of sensors along with a tailored and learning data processing will be key to innovations towards more complex and agile recycling processes. In this context, our multi-sensor solution focuses on a combination of advantages from HSI and Raman spectroscopy aided by efficient data integration (‘RAMSES-4-CE’ project, supported by the EU EIT Raw Materials).

 

 

 

 
The onset of the Ediacaran Nama Group sedimentation in Namibia?
Authors: Müller Inigo Andreas , Messori Fabio , Guillong Marcel , Peyrotti Giovan , Schirra Michael , Samankassou Elias , Linnemann Ulf , Hofmann Mandy , Zieger Johannes , Martignier Agathe , Bouvier Anne-Sophie , Venneman Torsten , Kouzmanov Kalin , Ovtcharova Maria
Published: February 2023

The final stage of the Proterozoic, the Ediacaran, shields fascinating insights on the development and dispersal of complex metazoans related to dramatic compositional changes in the atmosphere and hydrosphere.  Alternating sequences of siliciclastic and carbonate rocks of the Namibian Nama basin record the final stage of the Ediacaran and contain a vast amount of soft-bodied fauna, as well as some of the first biocalcifying organisms. However, the sparsity of ash beds at the base of the Nama group, preclude accurate and precise constraints on the onset of the Ediacaran biota in Nama group and correlation with chemo stratigraphic records worldwide.  Due to the scarcity of ash layers, we apply U-Pb dating to carbonate rocks especially from the lower stratigraphic sections of the Nama Group combining the spatial resolution of LA-ICP-MS and the high-precision ID-TIMS U-Pb dating. The combination with mineralogical and geochemical techniques (d13C, d18O, XRD, SEM, EPMA, CL imaging, LA trace element transects, Raman spectroscopy, clumped isotope thermometry, QEMSCAN, SIMS) enables us to better understand the nature of the analyzed carbonates to distinguish between more pristine and diagenetic phases.This study elaborates on the potential and limitations of carbonate U-Pb dating for improved stratigraphic correlation on these ancient pre-Cambrian marine carbonates from the Nama Group.
Factors driving Supraglacial Lake variability on ice shelves in Dronning Maud Land, East Antarctica
Authors: Mahagaonkar Anirudha , Moholdt Geir , Schuler Thomas V.
Published: February 2023

We have identified large spatiotemporal variability in the extent of supraglacial lakes on ice shelves in Dronning Maud Land, East Antarctica. While large lakes were found over Nivlisen and Roi Baudouin ice shelf areas, only small lakes were mapped over Fimbulisen and Muninisen. Preliminary analyses reveal a positive correlation between supraglacial lake extents (over specific ice shelves) and mean summer (December, January, February) temperatures and Positive Degree Days from ERA5. However, these correlations do not explain the large variability in overall Dronning Maud Land assessments. For instance, Fimbulisen area has the warmest summer temperatures and highest sum Positive Degree Days with very low lake extents. In contrast, the adjacent Nivlisen area with similar summer statistics has large spread of supraglacial lakes over the ice shelf area. We also identified that over specific melt years (e.g., 2016-2017, high lake extents; 2020-2021, low lake extents), all ice shelf areas with supraglacial lakes in Dronning Maud Land had relatively similar local lake extents, indicating the role of both regional and local factors influencing the ponding of meltwater. In this work, we attempt to identify the factors influencing melting and ponding in Dronning Maud Land. For this purpose, we use outputs from ERA5-Land and Modèle Régional Atmosphèrique (MAR) which have a higher spatial resolution (~10 km) than ERA5 (~31 km). At coarser resolutions climate models are deficient to capture localized processes that may have a crucial role in influencing surface melting and ponding – e.g., the katabatic winds. Outputs at higher resolutions may better constrain such small-scale phenomena and by using these datasets we may resolve the knowledge gap surrounding the controlling factors. Atmospheric factors in consideration are katabatic winds, cloudiness, precipitation, and albedo. Environmental factors such as blue ice, firn air content and surface topography will also be assessed to ascertain their influencing role. The results of this analysis will help in understanding the near-future evolution of supraglacial lakes on Dronning Maud Land and provide important insight into the future ice shelf stability in the region and also for improving estimates of the Antarctic ice sheet mass budget.
Chemical and dynamical variability in the middle atmosphere related to energetic electron precipitation
Authors: Salminen Antti , Asikainen Timo , Mursula Kalevi
Published: February 2023

Energetic electron precipitation (EEP) directly influences the high-latitude thermosphere and mesosphere. Precipitating electrons originate from the Earth’s magnetosphere and their precipitation to the atmosphere is driven by the solar wind. EEP produces odd nitrogen (NOX) and odd hydrogen (HOX) oxides which catalytically destroy ozone. During the winter, EEP-NOX survives for months, which enables its descent to the polar stratosphere. Several studies, based on both observations and models, have shown that EEP-induced ozone destruction leads to changes in temperature and dynamics in the atmosphere which strengthen the stratospheric polar vortex, a westerly wind system surrounding the pole. However, most observational studies on EEP effects have relied on reanalysis datasets which are mainly limited to the stratospheric altitude. Thus, observations of EEP effects on the atmosphere are still partly incomplete. In this study we use the AURA/MLS satellite measurements of atmospheric variables and the POES/MEPED satellite measurements of precipitating electrons to study EEP-related interannual variability in chemical and dynamical properties of the northern winter mesosphere and stratosphere in 2004-2022. We confirm the earlier findings of EEP effects on ozone and temperature in the polar region and on the polar vortex in the stratosphere, and also examine the related variability in the northern winter mesosphere. Moreover, we confirm our recent results about the role of planetary waves in modulating the EEP effect on the polar vortex.
Female representation across Copernicus journals
Authors: Popp Andrea , Stadmark Johanna , Timar-Gabor Alida
Published: February 2023

In an effort to assess the representation of women across all Copernicus journals, we assigned the apparent gender to each person serving on Copernicus editorial boards (1089 editors in total). Some people are present in more than one journal and can have different roles within one journal, however, we counted them only once per journal in our analysis. We identified the sex of a person by the typical gender association of their first name and by looking at pictures. We are aware that this approach to identifying biological sex can be limited and that gender identity cannot be inferred from this kind of analysis. Our assessment shows that the proportion of apparent female editors across all journals is between 10% and 57% with lower proportions among larger editorial boards. On average, we identified 27% of all editors to be female. We compare these numbers to the average representation of female scientists during EGU General Assemblies (GAs), which serves as a reference for the general gender distribution within the European geosciences community. Based on the self-reported gender of EGU GA participants, senior women constitute about one-third of the EGU participants, while 40% of the ECS participants identify as female. However, commonly more senior scientists are invited to join editorial boards. Thus, our initial assessment indicates that the estimated number of female scientists on editorial boards of Copernic journals nearly reflects the representation of senior female scientists attending EGU GAs. 
Characterisation of multi-scale deformation in NEGIS from microstructure analysis of the EastGRIP ice core
Authors: Kerch Johanna , Streng Kyra , Stoll Nicolas , Eichler Jan , Westhoff Julien , Jansen Daniela , Bons Paul , Weikusat Ilka
Published: February 2023

We present the results from a microstructural analysis of more than 1000 thin section samples from the East Greenland Ice Core Project (EastGRIP) ice core that is being drilled at the onset of the fast-flowing North East Greenland Ice Stream (NEGIS) since 2017, focusing on the grain boundary network and bubbles.The data were recorded directly at the drilling site with a Large Area Scanning Macroscope from the polished and sublimated surface of samples from between 0 and 2121 m ice depth. Most samples are cut vertically, along the core axis, but a selected number of perpendicular vertical and horizontal sections from volume samples are included, providing the opportunity to deduce the three-dimensional microstructure in these depths. Processing of the image data was done with the open source software Ice Microstructure Analyser, extracting a fully digitalized grain boundary network by applying machine learning for the classification of grain boundaries and air inclusions.We analysed the shape-preferred orientation (SPO) of grains and bubbles based on statistically computed parameters from the data set under consideration of available azimuthal core-orientation data reconstructed from visual stratigraphy data. These SPO parameters include grain size distribution, grain shape and derived measures like perimeter ratio and aspect ratio, and grain boundary orientation angle.The data show varying trends throughout the core and on different length scales, supporting and complementing earlier observations in the crystallographic-preferred orientation data from the same set of samples. We provide microstructural evidence for dynamic recrystallisation driven by deformation throughout the core. Specifically, we will discuss our findings of heterogeneities that point to internal deformation due to the occurrence of high strain localisation and link them to the observed complex pattern of anisotropy in the ice column.
Seismic Imaging of Heterogeneous Lithosphere Beneath the Unusually Broad Turkana Depression, East Africa
Authors: Kounoudis Rita , Bastow Ian , Ebinger Cynthia , Darbyshire Fiona , Musila Martin , Ogden Christopher , Ayele Atalay , Bendick Rebecca , Sullivan Garrett , Ugo Freddie , Mariita Nicholas , Kianji Gladys
Published: February 2023

Continental rifting is currently active in East Africa, where breakup of the African continent is generally occurring in relatively focused rift zones within two uplifted plateaus, with magma intrusions the primary mechanism for strain accommodation throughout the crust and mantle lithosphere. Linking the two narrow rift valleys is the low-lying, and as-yet poorly studied Turkana Depression - an unusually broad 300km-wide region of diffuse faulting, seismicity and magmatism. How the East African Rift has developed here remains elusive and is complicated by the fact the Depression was variably stretched by several superposed episodes of failed rifting since the Mesozoic. Utilising data from the NSF-NERC-funded TRAILS seismic network, we produce the first detailed crustal and uppermost-mantle shear-wave velocity model below the Turkana Depression, illuminating Moho and lithosphere-asthenosphere boundary topography that ultimately shed light on rift development in a multiply-rifted region. We find Turkana’s lithosphere is relatively melt-poor, unlike the Ethiopian rift and Plateau further north, which have undergone extensive lithospheric modification by voluminous Cenozoic flood-basalt magmatism and magma-assisted rifting. The lower crust below rift zones in Turkana is not associated with markedly slow (melt) or fast (cooled gabbroic intrusions) wavespeeds suggesting magmatic extension has not dominated rift development in Turkana. Throughout the Depression, the thinnest crust resides within failed Mesozoic rift zones which the present-day East African Rift appears to circumnavigate, not exploit. Fast uppermost mantle wavespeeds below the thinnest crustal regions indicate post-Mesozoic rifting, re-equilibrated and possibly melt-depleted mantle lithosphere, which now renders the plate stronger and more refractory than regions not previously rifted. Refractory Proterozoic lithosphere also present in southern Ethiopia may have influenced strain localisation and the broad, complex rift zone between Ethiopia and Kenya.
Constraining the carbon cycle in JULES-ES-1.
Authors: McNeall Douglas , Robertson Eddy , Wiltshire Andy
Published: February 2023

Land surface models are widely used to study climate change and its impacts, but uncertainties in input parameter settings and model errors hamper their use. We use Uncertainty Quantification (UQ) techniques to constrain the input parameters of JULES-ES-1.0, the land surface component of the UK Earth system model UKESM1.0. We use an ensemble of historical simulations of the land surface model to rule out ensemble members and corresponding input parameter settings that do not match modern observations of the land surface and carbon cycle. Using a Gaussian Process emulator trained on the ensemble to predict the model output, we can repeat this process for parts of parameter space where the model is not yet tested. We use history matching - an iterated approach to constraining JULES-ES-1.0 - running an initial ensemble and training the emulator, before choosing a second wave of ensemble members consistent with historical land surface and carbon cycle observations. We rule out 88% of the initial input parameter space as being statistically inconsistent with observed land surface behaviour. We use the emulator to perform 3 types of sensitivity analysis to identify the most (and least) important input parameters for controlling the global output of JULES-ES-1.0, and provide information on how parameters might be varied to improve the performance of the model, eliminate model biases, and make better carbon cycle projections.
DeepExtremes: Explainable Earth Surface Forecasting Under Extreme Climate Conditions
Authors: Mora Karin , Brandt Gunnar , Benson Vitus , Brockmann Carsten , Camps-Valls Gustau , Fernández-Torres Miguel-Ángel , Fincke Tonio , Fomferra Norman , Gans Fabian , Gonzalez Maria , Ji Chaonan , Kraemer Guido , Marco Eva Sevillano , Montero David , Reichstein Markus , Requena-Mesa Christian , Valero Oscar José Pellicer , Weynants Mélanie , Wieneke Sebastian , Mahecha Miguel D.
Published: February 2023

Compound heat waves and drought events draw our particular attention as they become more frequent. Co-occurring extreme events often exacerbate impacts on ecosystems and can induce a cascade of detrimental consequences. However, the research to understand these events is still in its infancy. DeepExtremes is a project funded by the European Space Agency (https://rsc4earth.de/project/deepextremes/) aiming at using deep learning to gain insight into Earth surface under extreme climate conditions. Specifically, the goal is to forecast and explain extreme, multi-hazard, and compound events. To this end, the project leverages the existing Earth observation archive to help us better understand and represent different types of hazards and their effects on society and vegetation. The project implementation involves a multi-stage process consisting of 1) global event detection; 2) intelligent subsampling and creation of mini-data-cubes; 3) forecasting methods development, interpretation, and testing; and 4) cloud deployment and upscaling. The data products will be made available to the community following the reproducibility and FAIR data principles. By effectively combining Earth system science with explainable AI, the project contributes knowledge to advancing the sustainable management of consequences of extreme events. This presentation will show the progress made so far and specifically introduce how to participate in the challenges about spatio-temporal extreme event prediction in DeepExtremes.
Comparison between Eulerian and Lagrangian models for simulating atmospheric conditions in urban environments
Authors: du Preez David Jean , Knote Christoph , May Maximilian
Published: February 2023

Populations in urban areas have continued increasing in developing and developed countries worldwide. The ability to accurately simulate the dynamical and chemical atmospheric conditions in urban areas is essential when investigating the health impacts related to environmental conditions in urban areas. To simulate atmospheric conditions in urban areas one must consider how the airflow is affected by urban structures, vegetation, and mesoscale meteorology as well as local emitters and non-linear chemical reactions. 

There are a variety of different models available to simulate atmospheric conditions in urban areas. These models differ in many ways such as numerical methods, spatial and temporal resolution, and initial and lateral boundary conditions. Here we compare an Eulerian (PALM) and a Lagrangian (GRAL) model to determine which model can best simulate atmospheric conditions in an urban environment. These numerical differences affect the computational resources required and therefore influence how each model can be used to study the urban environment. The initial and lateral boundary conditions used in the simulations are derived from the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) and a library of horizontal wind fields for PALM and GRAL, respectively. The results from both models will be compared for a domain over Heidelberg, Germany over a two-week period against hourly surface observations of wind and air quality parameters. 
The High Energy Particle Populations of Earth Mapped by Swarm and MMS
Authors: Toldbo Christina , Herceg Matija , Sushkova Julia , Denver Troelz , Henneke Jesper , Benn Mathias , Jørgensen Peter S. , Merayo José M.G. , Qamili Enkelejda , Hoyos Ortega Berta , Haagmans Roger , Vogel Pierre , Strømme Anja , Shulman Seth , Jørgensen John L.
Published: February 2023

The three spacecraft which constitute the Swarm mission are equipped with the Micro Advanced Stellar Compass (μASC) provided by the Technical University of Denmark (DTU) for attitude determination. Each μASC is comprised of three Camera Head Units (CHUs) for a total of nine cameras on the mission. The CCD sensor inside the CHUs are sensitive to energetic particle irradiation which appear as transient bright pixels dubbed ’Energetic Particle Detections’ (EPDs) on the star field images.
For more than five years the μASCs on-board Swarm have transmitted the occurrence of EPDs to ground and thereby effectively added high energy radiation monitoring capabilities to the Swarm mission. The high sensitivity, high sample rate (1-2 Hz), orientation of the camera heads, simultaneous measurements from all three spacecraft and near-polar orbits at an altitude of 450-510 km and allows for continuous and real-time monitoring of the high energy (>65 MeV) proton environment in LEO. This data uncover short and long term changes in particle flux in e.g. the South Atlantic Anomaly (SAA) of relevance for future mission planning.
The same radiation monitoring capability exists on NASA’s Magnetospheric Multiscale Mission (MMS) which, due to its highly elliptical orbit, survey the Van Allen radiation belts and detect enhanced radiation levels in the belts associated with geomagnetic storms. Combining data from the μASCs onboard Swarm and MMS provides unique insight into the injection mechanisms and dynamics of very high energy particles which is currently poorly understood. This work presents observations and results using high energy radiation data obtained from the μASC on board ESA’s Swarm mission, from February 2018 to February 2023, in combination with μASC data from MMS.
 
Minimizing the loss of radioactively contaminated sediment from the Niida watershed (Fukushima, Japan) through spatially targeted afforestation.
Authors: Abrams Floris , Sweeck Lieve , Camps Johan , Castillo-Reyes Grethell , Feng Bin , Onda Yuichi , Van Orshoven Jos
Published: February 2023

Government-led decontamination of agricultural land in the Fukushima accident (2011) region has lowered the on-site radiation risk considerably. From 2013 to early 2017, 11.9% of the land in the Fukushima disaster affected Niida watershed in Japan was remediated through topsoil removal. However, this resulted in a 237.1% increase in suspended sediment loads in the river for 2016 compared to 2013.  In contrast, sediment loads decreased by 41% from 2016 to 2017; this can be attributed to the effect of natural vegetation restoration on sediment yield and transfer patterns (Bin et al., 2022). Since radiocaesium firmly binds to the clay minerals in the soil, it is inevitably transported along with the sediments downstream to the river systems. These observations confirm that rapid, spatially targeted interventions, such as revegetation, e.g., through afforestation, have the potential to decrease the magnitude and period of increased exports of contaminated sediments. The CAMF tool (Cellular Automata-based Heuristic for Minimizing Flow) (Vanegas et al., 2012) was originally designed to find the cells in a raster representation of a watershed for which afforestation would lead to a maximal reduction of sediment exports with minimal effort or cost while taking sediment flow from cell to cell into account. In our research, we adapted the CAMF tool to account for the radiocaesium budgets associated with the transported sediments. We applied the approach to the Niida catchment, where land-cover changes in upstream decontaminated regions are detected using drone imagery and linked to increased sediment loads in the Niida river using long-term river monitoring systems. For example In 2014, agricultural land (18.02 km2) was one of the major land uses in the regions where decontamination was ordered, resulting in increased sediment loads from 2014 to 2016. By recognizing both the on- and off-site impacts of the remediation interventions and their temporal dynamics, the modified CAMF tool offers scope for supporting the formulation of spatio-temporal schemes for the remediation of agricultural land. These schemes aim to decrease the radiation risk for downstream communities and minimize the potential recontamination of already decontaminated sites.
Application of stable isotope methods (13C,18O) to link climate change-induced drought stress and bark beetle susceptibility in Austrian forests
Authors: Schott Katharina , Kitzler Barbara , Hoch Gernot , Grabner Michael , Ziss Elisabeth , Watzinger Andrea , Bauerhansl Christoph , Hood-Nowotny Rebecca
Published: February 2023

The impacts of climate change in forests are often cascading, affecting plant growth, plant performance but often also rendering trees susceptible to insect pathogen attack. Potentially these insect infestations could have a greater impact on the forest’s carbon sequestration potential, than the direct climate effects on plant growth and forestry production. Regional and context-specific responses to a changing climate are expected: In regions where forest productivity is constrained by low temperatures, such as high altitudes,  growth is likely to increase as temperatures rise, whilst in regions with limited water availability, a decline in growth is predicted as a result of more frequent and prolonged droughts and/or changing precipitation patterns.Norway spruce is high-yielding, easy to manage and has a number of economic advantages over broadleaf production.  Spruce is economically the most important and common tree species in Austria, making up over 50% the Austrian forestry area. Area-wide planting throughout Austria was supported for decades, which often led to planting in regions where the production risk for spruce was and remains high and where active management does not necessarily cover costs. This legacy of this planting policy means that stands are often still planted on sites, where the trees are close to the limit of suitability. Spruce has shallow roots and less access to deeper soil moisture, so it is particularly susceptible to drought stress. Trees that suffer from changing site conditions are likely to be more susceptible to disease and insect infestation than trees that are not exposed to additional site stresses. In an effort to identify sites that have suffered from drought in the past and that are vulnerable to possible pest infestations, a method to predict bark beetle susceptibility is being developed, based on stable isotope signatures in tree rings. Specifically, we will test whether the stable isotope data (¹³C,¹⁸O) in the tree rings can provide an accurate archive of information about past climate variability and physiological responses to environmental and geomorphological conditions: These data can provide historical insights into water status, in particular soil water availability and use, temperature and water consumption of individual trees. They can be correlated with detailed archived weather and precipitation data as well as easily measured parameters such as canopy temperature or spectral data. We will present our approach and the first results, which are based on samples from the Austrian forest inventory and complemented with samples from additional bark-beetle infested areas.
Advancing exposure modelling from seismic risk to multi-hazard analysis in urban and metropolitan areas
Authors: Pittore Massimiliano , Gomez Zapata Juan Camilo , Geiß Christian , Campalani Piero , Renner Kathrin
Published: February 2023

Exposure modelling is a critical factor in the assessment of risk from natural hazards. Athough often its role has been overshadowed by other risk components (most notably, hazard), an efficient estimation of exposure is key to improve confidence in impact analysis and forecasting and ultimately support decision makers to improve risk mitigation activities. This is particularly relevant in urban and metropolitan areas, where the density and complexity of the interplay between population, socio-economical assets and infrastructure is likely to foster non-linear risk amplification, possibly due to cascading phenomena. In the last decade several innovative methodological approaches have been proposed, building upon statistical modelling, exploiting heterogeneous data from remote sensing, and integrating machine learning techniques in order to improve understanding, formal description and representation of exposure in a wide range of applications. These activities have been originally developed within the community of seismic risk, and later increasingly extended to other natural hazards, acknowledging the need for a more general and flexible approach to exposure modelling in the context of multi-hazard and multi-risk applications.This is ever more important considering also the ongoing convergence of Disaster Risk Reduction (DRR) and Climate Change Adaptation (CCA) in the broader context of Comprehensive Risk Management (CRM).In this contribute we aim at providing an overview of the most recent advances that the authors have proposed in the field, outline the current challenge and perspectives in the field of exposure modelling, and draw a tentative roadmap for the next future. 
Chemical weathering during the PETM: Insights from stable and radiogenic isotopes in the Spanish Pyrenees
Authors: Jaimes-Gutierrez Rocio , Puceat Emmanuelle , Adatte Thierry , Wilson David J. , Pogge von Strandmann Philip , Blondet Justine , Castelltort Sebastien
Published: February 2023

We explore the feedback mechanisms at play during the climate recovery of the Paleocene Eocene Thermal Maximum (PETM) in a continental section of the Spanish Pyrenees, the Esplugafreda section. We combine isotopic and mineralogical proxies to assess the changes in the chemical weathering intensity and regime and explore their implications in this mid-latitude catchment. The changes in the clay mineral assemblages in two size fractions (<0.5 µm and 0.5-2 µm) were examined as paleoclimatic proxies. We also used these fractions to study the combined Sm-Nd and Lu-Hf radiogenic isotope systems to constrain the clay provenance and chemical weathering intensity. Furthermore, we measured lithium isotopes in the bulk clays to assess local changes in the weathering regime and clay neoformation during the PETM.The clay mineralogy reveals an interplay between detrital clay input during extreme events and more hydrolyzing conditions reflected in the presence of pedogenetic smectites during the onset and body of the PETM. The extent to which the clay samples deviate from the clay array (ΔεHf) show no variations throughout the section, indicating no increase in the chemical weathering intensity. Nonetheless, the δ7Li values show a distinct negative excursion during the recovery of the PETM in the Esplugafreda section. This excursion is coeval with an increase in the proportions of illite and chlorite relative to smectite, an indicator of increasing physical erosion.Our results suggest that the low surface reactivity of the floodplain deposit sediments resulted in negligible variations in the chemical weathering intensity recorded in the clays. Yet, the floodplain soils saw more fractionated lithium isotope compositions, contemporary with an increase in the detrital nature of the clay minerals. Climate change in the region was characterized by a substantial temperature increase with massive but short precipitation events, resulting in efficient sediment transport. Although weathering in the Pyrenees was kinetic-limited, both chemical weathering and physical erosion played a role in the climate recovery to pre-PETM conditions. Rapid climatic changes and their impact on the geological record are of utmost importance for understanding ongoing global warming and the associated feedback mechanisms on environmental conditions.
Sensitivity of Pine Island and Thwaites drainage basins to subglacial hydrology
Authors: Kazmierczak Elise , Pattyn Frank
Published: February 2023

Subglacial processes in Antarctica are difficult to directly observe and are one of the sources of uncertainty when modelling the response of ice sheets to environmental forcing. Subglacial processes pertain to the type of basal sliding or friction law used, where especially the contrast between viscous (linear) and plastic (Coulomb) sliding makes the latter far more responsive to changes at the marine boundary (Ritz et al., 2015; Brondex et al., 2019; Bulthuis et al., 2019; Sun et al., 2020; Kazmierczak et al., 2022).Besides the type of sliding, physical basal conditions, such as basal temperatures, bed properties (hard or soft), subglacial water flow and drainage, till properties, and mechanics, also directly affect the ice sheet flow (Clarke, 2005, Cuffey and Patterson, 2010, Kazmierczak et al., 2022),  by affecting the effective pressure (Bueler and Brown, 2009, Winkelmann et al., 2011, van der Wel et al., 2013).In this study, we investigate how variations in effective pressure determines the evolution of the main marine basins of the West Antarctic Ice Sheet (Pine Island and Thwaites glacier) which are currently exhibiting the largest ice mass loss of the Antarctic ice sheet.For this purpose, we employ different types of subglacial hydrology for soft and hard bed configurations, which we adapt to simulate individual drainage basins of the Antarctic ice sheet at a km-scale resolution, thus allowing for proper migration of the grounding line (e.g., Pattyn et al., 2013). These hydrological representations are included in a generalized basal sliding law (Zoet et al., 2020), implemented in the the f.ETISh/Kori model (Pattyn, 2017; Sun et al., 2020). Results are compared to results from a pan-Antarctic ice sheet model (Kazmierczak et al., 2022) and demonstrate the importance of detailed bed topography influencing the subglacial conditions upstream of the grounding line.
A microwave tomographic approach for contactless Multiple Input Multiple Output GPR systems
Authors: Soldovieri Francesco , Gennarelli Gianluca , Ludeno Giovanni , Esposito Giuseppe , Catapano Ilaria
Published: February 2023

Nowadays, Ground Penetrating Radar (GPR) systems working in contactless way deserve huge attention because, if mounted onboard of moving platforms like terrestrial and aerial vehicles, they allow the collection of a large amount of data, while keeping low complexity and time of the measurement step [1,2]. At the same time, multiple input multiple output (MIMO) GPR systems are worth being exploited because, being capable of gathering multiview and multistatic data, they allow an improvement of the reconstruction capabilities [3, 4]. However, the effective use of a contactless MIMO GPR requires the availability of properly designed data processing strategies able to manage the information acquired by this kind of systems and to provide an accurate reconstruction of the scenario under test.This contribute proposes a microwave tomographic approach, which faces the GPR imaging as a linear inverse scattering problem and it is suitable to process contactless multi-view and multi-static data. The approach is referred to the 2D scalar case, exploits a ray-based model of the scattering phenomenon, and accounts for the presence of the air-soil interface. Specifically, the approach extends to the case of MIMO systems the concept of the Interface Reflection Point (IPR) previously exploited to process contactless data gathered by means of a multi-monostatic GPR [2,5].At the conference, the approach formulation will be described in detail and results referred to virtual experiments will be provided in order to state the achievable imaging capabilities.[1] Miccinesi, L., Beni, A., & Pieraccini, M. (2022). UAS-Borne Radar for Remote Sensing: A Review. Electronics, 11(20), 3324.[2] Catapano, G. Gennarelli, G. Ludeno, C. Noviello, G. Esposito, and F. Soldovieri, "Contactless ground penetrating radar imaging: state of the art, challenges, and microwave tomography-based data processing," IEEE Geosci. Rem. Sens. Mag., vol. 10, no. 1, pp. 251-273, 2022.[3] García-Fernández, M., López, Y. Á., & Andrés, F. L. H. (2020). Airborne multi-channel ground penetrating radar for improvised explosive devices and landmine detection. IEEE Access, 8, 165927-165943.[4] Leone, G., & Soldovieri, F. (2003). Analysis of the distorted Born approximation for subsurface reconstruction: Truncation and uncertainties effects. IEEE Transactions on geoscience and remote sensing, 41(1), 66-74.[5] Catapano, L. Crocco, Y. Krellmann, G. Triltzsch, and F. Soldovieri, “Tomographic airborne ground penetrating radar imaging: achievable spatial resolution and on-field assessment,”, ISPRS J. Photogram. Remote Sens., vol. 92, pp. 69–78, June 2014.
Turbulence and whistlers in magnetic clouds observed by Solar Orbiter
Authors: Werner A. L. Elisabeth , Yordanova Emiliya , Dimmock Andrew P. , Svenningsson Ida
Published: February 2023

Kinetic processes control the cross-scale energy transfer between large-scale dynamics and dissipation in the solar wind. Large-scale magnetic flux ropes, also known as magnetic clouds (MCs), inside interplanetary coronal mass ejections (ICMEs) have been shown to effectively drive magnetospheric disturbances, but little is known about the turbulence properties and wave-particle interactions inside the MCs.Here, we study the properties of the turbulence inside MCs between 0.3-1 AU observed by Solar Orbiter. We find that the spectral index in the inertial range fits Kolmogorov’s power law, but in the high-frequency regime we find a spectral bump at the beginning of a steeper power law regime. This is likely due to the presence of a significant number of whistler waves inside the MCs.We have developed an automated search algorithm to find and record the properties of whistler waves inside MCs observed by Solar Orbiter. We find that MCs contain a significant number of whistler wave events with high magnetic field wave power (>0.5 nT2), which we do not find in the ICME sheath regions. We study these waves and attempt to determine their generation mechanism. In order to explore possible relations between the turbulence and the presence of whistler waves, we also determine the mean energy transfer rate, the magnetic field intermittency and the turbulent properties of the MCs and compare with the sheaths.  
Probabilistic orbit solutions in GNSS
Authors: Järvinen Heikki , Navarro Trastoy Angel , Tuppi Lauri , Mayer-Gürr Torsten
Published: February 2023

We discuss a concept of probabilistic orbit. If correctly constructed, an ensemble of equally plausible orbits is a proper representation of the underlying true and unknown probability distribution of orbits. Hence, the probabilistic orbit is determined by the entire sample and its statistical properties rather than any individual ensemble member. We explore the concept by starting from an ensemble of atmospheric state estimates generated at ECMWF (N=51). The ensemble mean closely corresponds to the most likely atmospheric state estimate, and the ensemble spread to its inherent uncertainty. We compute separately a GNSS orbit solution for each unique atmospheric state (N=51). Thus, we essentially sample one uncertain information source the GNSS orbits are known to be sensitive for. Thereby, uncertainty in the atmospheric state estimate is explicitly propagated to the ensemble of orbit solutions. The concept leads to interesting corollaries. Precise point positioning using the probabilistic orbit, for instance, becomes probabilistic, too.
Studying the South Atlantic Anomaly temporal evolutionfrom 1998 to 2022 using the SEM-2 proton flux
Authors: Ginisty François , Wrobel Frédéric , Ecoffet Robert , Mandea Mioara , Michez Alain , Balcon Nicolas , Ruffenach Marine , Mekki Julien
Published: February 2023

The SEM-2 (Space Environment Monitor-2) instrument embedded on the NOAA-15 Low Earth Orbit satellite provides measurements of trapped protons in the Van Allen inner belt from 1998 to nowadays. This continuous amount of measurements enables us to study the temporal evolution of the dynamics of the South Atlantic Anomaly (SAA) over more than two solar cycles.In particular, we study the temporal evolution of the area of the SAA. We observe that the area of the SAA is anti-correlated with the solar activity. Two physical process explain this anticorrelation.First, the more the Sun is active the more it disables the cosmic rays to reach the Earth Magnetosphere and to fill the inner radiation belt with protons. Then, when the Sun in more active, the upper atmosphere is warmer and therefore absorbs more protons from the radiation belt.Then, we investigate the protons flux centroid of the SAA. The temporal evolution of its position, latitude and, longitude is studied over the same time interval (1998-2022). We notice the latitude of the centroid is also anti-correlated with the solar activity whereas the longitude seems absolutelyindependent. Some explanations are given for these observations.The temporal evolution of the position of the centroid shows a drift of the SAA. Indeed from 1998 to 2022 the SAA drifted of about 7 degrees West.The SEM-2 instrument measures flux for protons of different energies (16, 36, 70 and, 140 MeV). For each energy, the SAA dynamic has a similar trend but with different values. These differences are investigated and the results discussed.
Point Data Assimilation in Firedrake and Icepack
Authors: Nixon-Hill Reuben W. , Shapero Daniel , Cotter Colin J. , Ham David A.
Published: February 2023

We present methods and tools which significantly improve the ability to estimate quantities and fields which are difficult to directly measure at large scales, such as the fluidity of ice, using point data sources from remote sensing. Our tools work with both sparse and dense point data with estimated quantities and fields becoming more accurate as the number of measurements are increased. These are often used as input variables to mathematical models that are used to make predictions so improving their accuracy is of vital importance.
 
The tool we introduce, Firedrake, generates highly optimised code for solving PDEs via the finite element method. It is easy to use, can be integrated with other python libraries, and is scalable for use on high performance computers. As proof, we highlight Icepack, a Python library for solving the equations of motion of glacier flow, which is written using Firedrake. Firedrake has an interface to the dolfin-adjoint/pyadjoint tool which allows these data assimilation problems to be solved with just a few lines of code by automatically generating the adjoint system of PDEs.
 
By carefully considering the nature of finite element method solutions, we show, using Firedrake and Icepack, how the choice of misfit functional (i.e. objective function) significantly impacts our inferred fields. This required the development of new infrastructure not previously available in these automated code generation tools.