bluuebunny/crossref_metadata_2025 huggingface dataset:
Drivers of eastern Andean Plateau incision from integrated thermochronology and thermo-kinematic modelling
Authors: Falkowski Sarah , Glover Chloë , Buford Parks Victoria , McQuarrie Nadine , Perez Nicholas , Ehlers Todd A.
Published: February 2023

Proposed drivers of eastern Andean Plateau river incision in the Pliocene include climate change, dynamically driven plateau uplift, and long-wavelength surface uplift above deep basement structures. However, the evaluation of each mechanism has been hampered in previous studies due to the lack of along-strike data on the timing and extent of canyon incision. In addition, the magnitude of exhumation, permissible structural geometries, and integration of the long-term deformation, erosion, exhumation, and sedimentation histories remain poorly understood.This presentation focuses on two balanced geologic cross-sections and thermochronologic bedrock sample transects across the Andean Plateau, Eastern Cordillera, and Subandes in southern Peru. Based on (i) age-distance and age-elevation patterns of >80 new thermochronologic dates (apatite and zircon (U-Th)/He and fission-track) from plateau, interfluve, and canyon sample locations; (ii) inverse thermal history model results; and (iii) flexural and thermo-kinematic modeling, we highlight similarities and differences in thermochronometric age patterns, exhumation magnitude, structural geometries, and shortening rates between each section.Results show that the first-order thermochronometric age pattern is a function of rocks' vertical and lateral movement over basement ramps and resulting exhumational erosion. This pattern is superimposed with a regional and synchronous incision-related exhumation signal since the Pliocene. While this incision occurred independent of structural deformation, the exhumation magnitude and difference in interfluve and canyon thermochronometric ages require the presence of a tectonic contribution to exhumation. We conclude that uplift over a basement ramp in the Eastern Cordillera and a decrease in shortening rates since ~10 Ma set the stage for climate-enhanced incision to occur in southern Peru.
Earthquake Cycle of the East Anatolian Fault Between Palu-Erkenek (Eastern Türkiye): Insights of Tectonic Geodesy
Authors: Özarpacı Seda , Doğan Uğur , Ergintav Semih , Çakır Ziyadin , Zabcı Cengiz , Özdemir Alpay , Ayruk Efe Turan , Farımaz İlay , Köküm Mehmet
Published: February 2023

The East Anatolian Fault (EAF) is one of the continental transform systems in the Eastern Mediterranean, with a length of about 420 km between Karlıova (Bingöl) in the northeast and Türkoğlu (Kahramanmaraş). The 24 January 2020 Sivrice earthquake with Mw 6.8 once again demonstrated the seismic potential of this sinistral strike-slip fault.The recent earthquakes and discoveries creeping along the Palu Segment (~100km far to the NE of epicenter of Mw6.8 earthquake) by geodesy- and seismology-based studies increase scientific attention. The spatio-temporal characteristics of the creep observed along the Palu Segment were investigated using nearfield GPS, InSAR, and creepmeter data. After Mw6.8 earthquake, we expanded our study area towards the Pütürge Segment in the south to determine the postseismic effects of the 24 January 2020 earthquake and the kinematics of the Pütürge Segment using multidisciplinary methods (GNSS, creepmeter, InSAR, seismology, paeloseismology) and to investigate the effects on the surrounding faults.During the first year of the project work, a new GNSS network was established in the region and these networks will be regularly measured every six months. In addition, two permanent GNSS stations were installed. Additionally, using Sentinel-1 data sets, surface deformations mapped by PSINSAR analysis. Generally, post-earthquake effects continue and deformations moved to the SW part of unbroken part of Pütürge segment and based on the creepmeter data, surface deformations still continue at the epicenter locations, following the logarithmic afterslip responce.This work is supported by TUBITAK project number 121Y400. Keywords: East Anatolian Fault, Earthquake, GNSS, InSAR
Performance of the Picarro CRDS water isotope analyzer for δ2H tracer studies
Authors: Hofmann Magdalena E. G. , Bhattacharya Joyeeta , Woźniak Jan , Yan Jinshu , van Zwieten Ruthger
Published: February 2023

The Picarro water isotope analyzers (L2130-i/L2140-i) have become a standard technique to measure the natural abundance of δ18O, δ2H and 17O-excess of water isotopes in climate, environment, and hydrological studies. In addition, some applications require to measure highly enriched δ2H water isotope samples, e.g., when tracing water flows in hydrology. In this case, the 2H/1H ratio is used as a tracer when fluorescent tracers are not an option, e.g., when tracing drinking water.Measuring highly enriched water samples with optical spectroscopy comes along with two challenges: (i) the memory effect, the carryover from small fractions of water from one sample to another, and (ii) the spectroscopic limits of the analyzer. Here, we address both challenges by characterizing the memory effect for highly enriched δ2H samples considering the recently developed express mode that allows to reduce/remove the memory effect at a much faster rate compared to the standard mode [1, 2] and by reviewing the spectroscopic limits of the analyzer.In this study, we tested the performance of the Picarro L2130-i water isotope analyzer for a set of samples with varying 2H/1H ratios of 0.1 to 2.0% (corresponding to δ2H values of about 6,000 to 130,000‰). We found that (i) the analyzer shows an excellent linearity over a high δ2H enrichment range (up to 130,000‰); (ii) the analyzer shows a negligible concentration dependence at high enrichment levels; (iii) the spectroscopic limits of the analyzer can be extended by reducing the injection volume (<1.8uL); (iv) the memory effect can be reduced significantly when using the express mode compared to the standard mode.Our results show that the Picarro L2130-i water isotope analyzer is an adequate tool for measuring highly enriched δ2H water samples, and we will discuss best practices when measuring these samples.   References[1] Hofmann, M. E. G., Lin, Z., Woźniak, J., and Drori, K.: Improved throughput for δ18O and δD measurements of water with Cavity Ring-Down Spectroscopy, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14254, https://doi.org/10.5194/egusphere-egu21-14254, 2021.[2] Landais, A., Minster, B., Zuhr, A., Hofmann, M., and Fourré, E.: Performances of express mode vs standard mode for δ18O, δD and 17O-excess with a Picarro analyzer, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4278, https://doi.org/10.5194/egusphere-egu22-4278, 2022.
The Earth Climate Observatory (ECO) space mission concept for themonitoring of the Earth Energy Imbalance (EEI)
Authors: Smeesters Lien , Dewitte Steven , Mauritsen Thorsten
Published: February 2023

Monitoring the Earth Radiation Budget (ERB) and in particular the EarthEnergy Imbalance (EEI), is of paramount importance for a predictiveunderstanding of global climate change.   We propose the new EarthClimate Observatory (ECO) space mission concept for the monitoring ofthe EEI.The EEI is defined as the small difference between the two nearly equalterms of the incoming solar radiation, and the outgoing terrestrialradiation lost to space. Making a significant measurement of the EEIfrom space is very challenging, and requires a differential measurementwith one single instrument of both the incoming solar radiation and theoutgoing terrestrial radiation. The instrument that allows such adifferential measurement is an improved wide field of view electricalsubstitution cavity radiometer.The wide field of view radiometer will observe the earth from limb tolimb. A single measurement footprint is a circle with a diameter around6300 km. For the discrimination of cloudy and clear skies, a higherspatial resolution is needed. This will be obtained from two wide fieldof view cameras, a visible wide field of view camera for thecharacterisation of the spatial distribution of the reflected solarradiation, and a thermal infrared wide field of view camera for thecharacterisation of the spatial distribution of the emitted thermalradiation.
Numerical modelling of rapidly-rising glacier outburst floods
Authors: Jóhannesson Tómas , Zwinger Thomas , Råback Peter , Ruokolainen Juha
Published: February 2023

Glacier outburst floods, or jökulhlaups, from subglacial geothermal areas, marginal lakes and subglacial volcanic eruptions are common in Iceland and they pose a substantial hazard to settled areas as well as to roads, communication lines and other infrastructure near glaciers. Jökulhlaups have attracted increasing attention in recent years in many glacier areas because of an increased frequency due to the formation of terminus and marginal lakes in connection with global warming and the associated glacier downwasting. Jökulhlaups can be categorized into two groups, slowly and rapidly rising, with marked differences in the flood hydrographs. Slowly-rising jökulhlaups are traditionally explained by the theory of Nye (1976) through a conduit-melt–discharge feedback mechanism. The initial subglacial propagation and the development of the flood hydrograph of rapidly-rising jökulhlaups is, on the other hand, not quantitatively understood. We present observations of glacier outburst floods from W-Vatnajökull in Iceland that may be interpreted in terms of a conceptual theory for such floods as a pressure wave in the basal hydraulic system that propagates downglacier and creates the initial flood path by lifting the glacier from its sole. This theory is being implemented as a numerical model for rapidly-rising jökulhlaups in the Elmer/Ice Open-Source Finite-Element Software. The model describes the subglacial propagation of the jökulhlaup front using visco-elastic plate dynamics for the overlying glacier ice combined with a turbulent sheet model for the subglacial water flood. The evolution of the subglacial flooded area is simulated numerically through the solution of a contact problem that represents the lifting of the ice from the underlying glacier bed where the subglacial water pressure exceeds the normal stress in the ice at the sole of the glacier. We hence can identify 4 crucial components of the model: 1) A visco-elastic ice-deformation model, 2) a two-dimensional pressurized water-sheet model based on Manning’s law for turbulent friction in water flow, 3) the solution of a contact problem induced by hydraulic jacking of the glacier, and 4) the consistent (in terms of the spatial stress distribution) solution of the fluid–structure interaction between the ice and the water-sheet. We present and discuss these different aspects in terms of their numerical implementation in Elmer/Ice. The aim of the model is to explain the speed of propagation of the subglacial flood front at the beginning of the flood as well as the time-dependent flood hydrograph after the flood bursts out from under the glacier at the ice margin.
INSPIRE-SAT7: Pre-Flight radiometric validation and calibration of a miniaturized Earth’s Radiative Budget satellite
Authors: Van Laeken Lionel , Bolsée David , Pereira Nuno , Meftah Mustapha , Sarkissian Alain , Damé Luc , Dufour Christophe , team the INSPIRE-SAT
Published: February 2023

INSPIRE-SAT 7 is a French 2-Unit CubeSat primarily designed for Earth and Sun observations.  This mission is part of the International Satellite Program in Research and Education (INSPIRE). This satellite will be deployed in Low Earth Orbit (LEO) in 2023 as the first step of the so-called ‘Terra-F’ constellation that will provide spatio-temporal resolution for Earth Energy Imbalance (EEI) measurements.
This new scientific and technological pathfinder CubeSat mission (INSPIRE-SAT 7) is equipped with various channels on all sides. Among them: the Total Solar Irradiance Sensor (TSIS) payload, the Ultra-Violet Sensor (UVS) using a new generation of solar blind detectors designed to monitor the integrated Solar Spectral Irradiance (SSI) in the Hertzberg continuum, and the Earth Radiative Sensor (ERS) payload, designed to measure some Earth’s Radiative budget (ERB) components such as the outgoing short and long wave radiation at the top-of-the atmosphere for climate change studies.
The Belgian Radiometry Characterization Laboratory (B.RCLab) of the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) is the partner responsible for the pre-flight absolute calibration and radiometric characterization of INSPIRE-SAT7 TSIS and UVS payloads.
In this work we will first describe the INSPIRE-SAT7 concept, design, scientific and operational objectives. We will then present B.RCLab facilities along with its radiometric characterization benches, including the absolute calibration capabilities and its traceability. Finally, the main results of the INSPIRE-SAT7 pre-flight calibration campaign, which took place in November 2022, will be presented. These results allowed to calculate the sensors on-orbit calibration coefficients that are crucial to perform traceable absolute EEI measurements. A radiometric comprehensive uncertainty budget will be presented along the sensors’ calibration coefficients.
Mapping the environmental radioactivity in Catalonia using a mobile unit with LaBr3 scintillation detectors.
Authors: Prieto Elena , Cerezo Agustin , Reichardt Ignasi , Salvadó Marçal
Published: February 2023

This study describes the equipment implementation of a mobile gamma spectrometry unit using LaBr3 detectors and the process followed to obtain a radiological map of Catalonia (Spain). The mobile unit consists of two 2”x2” LaBr3 scintillation detectors mounted on the top of a 4x4 car. To obtain the preliminary map, the extension of Catalonia was divided in 1425 cells of 5x5 km2. Before starting the measurements, we planned a route to ensure a proper distribution and a minimum quantity of spectra within each cell. The car is equipped with a portable computer to control spectra acquisition and a GPS system that associates a position to each spectrum. Each spectrum is stabilised and calibrated. During the acquisition, the computer placed inside the car shows, in real-time, the value of the ambient dose equivalent and the exact location. Therefore, when the software obtains an unexpected high value, the driver of the car can modify the route to acquire more spectra of the area. The first data set of measurements included 70000 spectra obtained during stable weather conditions and represent the preliminary results of the radiological map, as other data campaigns are currently under preparation. In this study, we present the ambient dose equivalent map of Catalonia and isotopic information of interest, such as punctual detections of 137Cs and 131I and other radionuclides. The origin of these detections is analysed and explained in detail.
Bulge Formation, Water Jetting and Drifting at Strokkur Geyser, Iceland, derived from Video Camera Data
Authors: Karmacharya Sandeep , P. S. Eibl Eva , Shevchenko Alina , Walter Thomas , Páll Hersir Gylfi
Published: February 2023

Strokkur geyser in Iceland is located in the Haukadalur valley and features jetting water fountains of hot water every few minutes. In earlier studies we found that Strokkur geyser passes through typical phases: eruption, conduit refilling with water, gas accumulation in a bubble trap and regular bubble collapses at depth in the conduit (Eibl et al. 2021). In this presentation we focus on the blue bulge that forms at the beginning of an eruption and the following jetting and drifting of the water fountain. We analysed video camera data from 2017, 2020 and 2022 from the ground and from drones to assess the bulge heights and formation speeds. We find that an up to 0.5 m high water bulge forms within 0.7 s at an average speed of 0.6 m/s. Following the bulge burst, we subdivide the eruption phase into a water jet phase and a water drift phase. The water jet reaches a mean height of 16.2 m rising at a maximum average speed of 10.2 m/s. 5 s after maximum jet height is reached the water has drifted to a mean height of 25.6 m at a constant drift speed of 2.0 m/s. We find that eruptions that feature larger bulges also feature larger jet heights and discuss whether there is a link between eruption height and waiting time after eruptions.  
Realistic volcanic deformations synthesis based on simulation data via generative model
Authors: Beker Teo , Song Qian , Zhu Xiao Xiang
Published: February 2023

Volcanic eruptions are large-scale rare events causing extensive economic damage and loss of life each year. About 1500 volcanoes are considered active, and 800 million people live less than 100km away from them. Therefore, forecasting volcanic activity and eruptions are of great significance.The most precise way to monitor volcanoes and volcanic deformation is onsite monitoring; however, many active volcanoes are inaccessible. In the past years, Interferometric Synthetic Aperture Radar (InSAR) technology has been utilized with the help of deep learning (DL) to detect fast, intense volcanic deformations automatically. Previously, we employed the InSAR data with state-of-the-art processing to achieve high deformation accuracy over longer periods and apply DL to detect subtle long-term volcanic deformations automatically. Like the mentioned approaches, we face the challenges of small training sets and the gap between the train and test set.The DL model is trained on synthetic data and makes many false positive detections on the real test set. Grad-CAM analysis uncovered that the false detections are activated by the region-specific patterns of salt lake deformations, slope processes, and residual tropospheric noise. To increase the diversity of synthetic samples and reduce the false positives, we apply generative adversarial networks (GANs), to transfer the style of realistic terrain to synthetic data.This approach allows the generation of an infinite amount of synthetic data containing the regional deformation patterns and can be replicated for other regions. Since we are using real and synthetic data, it is significant that model can be trained with unpaired images. We employ a multi-domain and bidirectional state-of-the-art image-to-image translation model, StarGAN v2. We test the model on different tasks. The first task is to learn the transformation from synthetic background data to real background data. For volcanic deformations, we rely on established models for volcanic deformation simulations, like Mogi, Okada, or volumetric models. The second task demands the model to translate between synthetic and real and volcanic and non-volcanic domains. This model is capable of directly generating realistic-looking samples with volcanic deformations but with less control than the previous approach.
Hydrological simulation of flow rates in (un)gauged catchments of East-Flanders (Belgium) by the SWAT+ and PDM models.
Authors: Braet Kobe , Van Der Veken Lara , Tronquo Emma , Jans Jonas-Frederik , Verhoest Niko
Published: February 2023

Hydrological models are key instruments to predict hydrological extremes, such as droughts and floods. These hydrological extremes are becoming more and more frequent in Belgium. Therefore, creating a climate robust water system is becoming a priority. This research aims to provide flow rate predictions for several catchments in the province of East-Flanders based on meteorological, soil, land use and DEM data. These were collected by local monitoring networks and transformed by, among others, local pedotransfer functions and spatial interpolation methods.A physically based model (SWAT+) is used to simulate flow rate estimates for (un)gauged catchments and to calculate different scenarios related to land use change or a changing climate. The simulated flow rates are used as training data for a simple conceptual model (PDM). The PDM-model is more suited for real-time modelling and can be used as a basis to take policy decisions. The strength of physically based models is that they require minor calibration, while conceptual models have a more feasible computation time. By combining the strengths of both models, an estimate can be made for the flow rates in different (un)gauged catchments of East-Flanders.
Assessing the response of particulate matter stoichiometry to ocean alkalinity enhancement
Authors: Groen Anna , Kittu Leila , Ortiz-Cortes Joaquin , Schulz Kai , Riebesell Ulf
Published: February 2023

Ocean Alkalinity Enhancement (OAE) is one of the most promising ocean-based negative emissions technologies (NETs) currently discussed. Dissolution of alkaline minerals such as olivine or quicklime in the surface seawater elevates total alkalinity (TA), thereby increasing the oceanic CO2 uptake capacity. Depending on the mineral used, increased TA may have different consequences for marine pelagic ecosystems and water column biogeochemistry that are still unknown, creating a need for empirical data. Our study reports on the particulate matter stoichiometry of a pelagic ecosystem in response to a gradient of elevated alkalinity levels and under different alkaline mineral applications. Ten offshore mesocosms were deployed in the mesotrophic waters of the Raunefjord off Bergen, Norway, from May – July 2022. Using NaOH, a delta alkalinity gradient was created (∆TA = 0, 150, 300, 450, and 600 µmol·L-1), resulting in two sets of five alkalinity levels each. To simulate the application of olivine (Mg2SiO4) vs. calcium-based minerals for OAE, corresponding amounts of MgCl2 and CaCl2 were each added to the respective treatments. Each mesocosm of the silicate-based OAE treatments additionally received 70 µmol·L-1 Si(OH)4, simulating the concomitant release of silicate under silicate-based mineral dissolution. We found significant differences in the production of biogenic silica between the two mineral simulations, indicating beneficial conditions for diatoms when silicate-based minerals are dissolved. However, the hypothesis of calcium-based mineral dissolution being favorable for calcifying organisms was not supported in our study. Neither the concentrations of particulate inorganic carbon (PIC) nor its ratio to particulate organic carbon (POC) was significantly different between TA treatments and mineral type. Additionally, increased TA had a negative effect on particulate organic nitrogen (PON) and phosphorus (POP) concentrations resulting in increased POC:PON and POC:POP ratios with higher alkalinity in both mineral simulations, yet more evident in the silicate-based treatments. Hence, the interaction of OAE and mineral effect on the particulate matter stoichiometry is possibly not induced by a single factor, yet by a variety of drivers, e.g. phytoplankton species specific physiology or food web interactions, such as grazing pressure. These results provide useful insights for better assessing ecological risks and co-benefits of OAE, like possible CO2 limitation of primary producers or ecosystem restructuring, thus will help to inform the practical implementation of large-scale OAE applications for carbon dioxide removal.
Study on combination approaches for hydrological angular momentum determined from climate data
Authors: Nastula Jolanta , Kur Tomasz , Śliwińska Justyna , Wińska Małgorzata , Partyka Aleksander
Published: February 2023

Geophysical interpretation of polar motion (PM) and finding the sources of its excitation is an important but challenging task that takes place on the boundary between geodesy and geophysics. Especially the role of hydrological signals in PM excitation is not yet fully understood, mainly because of the lack of agreement between estimates of hydrological angular momentum (HAM) computed from different data sources (e.g., land surface models, global hydrological models, satellite gravity measurements).The recently observed climate changes affect the global distribution and transport of continental water mass, which may also influence the HAM. Projections of past and future changes in the physical and chemical properties of the atmosphere, ocean, and hydrosphere caused by climate change are delivered by climate models, which are collected and made available to the public in the frame of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). Such models provide many of variables, including variations in soil moisture and snow water storage, which are necessary for HAM computation. However, CMIP6 models differ in terms of initial conditions, physical properties of atmosphere, oceans, hydrosphere, and climate forcing. Such divergences obviously contribute to the differences between various CMIP6-based HAM series.In this study, we investigate various groups of models according to providing institute, mean of selected models and more sophisticated combinations determined using different methods like e.g., variance components estimation, three cornered hat method. The obtained series are analyzed and evaluated in several spectral bands. The goal of such study is to check whether grouping or combining the models could improve the consistency between CMIP6-based HAM and hydrological signal in geodetically observed PM excitation. To evaluate the combined CMIP6-based HAM series, we compare them with geodetic residuals (GAO) obtained from geodetic angular momentum reduced by atmospheric and oceanic signals, as well as with HAM computed from data from Gravity Recovery and Climate Experiment (GRACE) mission. Generally, the analyses confirm the results obtained from previous studies (Nastula et al. 2022). It is possible to find grouped CMIP6 models that provide HAM series as or more compliant with GAO than HAM determined from GRACE.
Deciphering the variation of magnetic fabric intensity across the Main Central Thrust in Garhwal Himalayas
Authors: Borgohain Asha , Gairola Pradeep , Bhatt Sandeep , Rana Virendra , Banerjee Sayandeep
Published: February 2023

One of the key aspects of understanding the rapid exhumation of Himalayan core, is to understand the variation of deformation intensity occurring along the major tectonic unit i.e., the Main Central Thrust (MCT). Quantification of magnetic fabrics, derived from analysis of anisotropy of magnetic susceptibility (AMS), defines the strain path in the form of an ellipsoid and provides a rich source of information on the structural evolution of rocks throughout the MCT. The approach of this study is to integrate field and AMS parameters, where field foliation from 73 planes has orientation trending NW-SE with a moderate dip of about 600 (best fit great circle) The magnetic foliation is found to be parallel to the field foliation. Variation in orientation direction of magnetic lineation implies the dominance of superposed folding in the study area. The degree of anisotropy (Pj), which quantifies the intensity of preferred orientation of magnetic minerals show values ranging from 1.1 to 1.8. The AMS study reveals that the shape parameter(T) of susceptibility ellipsoid, in most of the samples are positive representing an oblate ellipsoid. To be more precise, this study reflects the inter-relationship between field structures, superposed folding, magnetic fabric parameters to understand the exhumation of Himalayan core.
Evaluation of Spectral Mixing Techniques for Geological Mixture in a Laboratory Setup: Insights on the nature of mixing
Authors: Sahoo Maitreya Mohan , Rajendran Kalimuthu , Pattathal Vijayakumar Arun , Mathew Shibu K. , Porwal Alok
Published: February 2023

Geological mixtures having endmembers mixed at a fine scale pose a challenge to estimating their fractional abundances. Light incident on these mixtures interacts both at multilayered and surface levels, resulting in volumetric and albedo scattering, respectively. Accounting for these effects necessitates a nonlinear spectral mixing model approach rather than conventional linear mixing. In this study, we evaluate the performances of linear and various nonlinear spectral mixing models for an intimately mixed geological mixture, i.e., a banded hematite quartzite (BHQ) sample. The BHQ sample with distinct endmembers of hematite and quartzite facilitated our study of the behavior of light on two-component nonlinear mixtures. In a laboratory-based experimental setup, we used a spectroradiometer of full spectral range in the visible and near-infrared regions (350 to 2500nm) to acquire a hyperspectral image of the BHQ sample. It was followed by the identification of nonlinearly mixed regions and inferring changes in their spectral features. The nonlinearity induced in these regions was attributed to two significant causes- (1) the fine scale of spectral mixing and (2) the spectroradiometer sensor’s limited ability to spatially distinguish between focused and neighboring points, thereby producing a point spread effect. We observed the effects of nonlinear spectral mixing for our sample by changing the sensor’s height from 1mm to 5mm, to simulate fine and coarse-resolution images, respectively. The spectral mixing was modeled using the existing mapped ground truth fractional abundances and library endmembers’ spectra by linear mixing and established nonlinear techniques of the generalized bilinear model (GBM), polynomial post-nonlinear model (PPNM), kernel-based support vector machines (k-SVMs). The evaluated performance metric of reconstruction error revealed the nonlinearity effect in image pixels through statistical tests and nonlinearity parameters used in these models. It was further observed that the associated nonlinearity increases from fine to coarse-resolution images. The minimum error of image reconstruction was observed for the polynomial post-nonlinear model, with a single nonlinearity parameter and an average reconstruction error (ARE) of 0.05. Our study provided insights into the nature of nonlinear mixing with endmember composition and particle sizes.
Assessment of fire weather index calculations in Europe
Authors: Bohlmann Stephanie , Laine Marko
Published: February 2023

Wildfires caused by extreme weather conditions e.g high temperatures and drought have been increasing both in frequency and magnitude in the recent years. Due to the changing climate also regions with few recorded forest fires in the past are likely to be more frequently affected by wildfires. These wildfires have many social, economic, and environmental impacts. The EU funded SAFERS project, Structured Approaches for Forest Fire Emergencies in Resilient Societies, is creating an open and integrated platform featuring a forest fire decision support system in order to support societies becoming more resilient when acting against forests fires. The platform will, among other information, provide weather forecasts and forest fire indices to assess the risk of forest fires. Using the Canadian Forest Fire Weather Index (FWI) system [Van Wagner, 1974], fuel moisture (FFMC, DMC, DC) and fire behaviour indices (ISI, BUI, FWI) can be calculated using solely meteorological parameters (temperature, relative humidity, wind speed, and 24-hour precipitation). The Canadian FWI has been proved useful for forest fire risk assessment in different regions and has been adapted by multiple meteorological agencies worldwide. In our study, we use high resolution deterministic weather forecasts, as well as medium-range and extended-range weather forecasts provided by the European Centre for Medium-Range Weather Forecasts to calculate the FWI indices for up to 3, 15 and 46 days ahead, respectively. In our contribution we will present preliminary results of FWI verification and calibration methods.
References:Van Wagner, C. E.: Structure of the Canadian Forest Fire Weather Index, Departmental Publication 1333, Environment Canada, Canadian Forestry Service, Petawawa Forest Experiment Station, Chalk River, Ontario, p. 49, 1974.
Monitoring local Ocean Heat Content changes with satellite altimetry and space gravimetry to assess the variability of the Meridional Heat Transport in the North Atlantic: the 4DATLANTIC-OHC Project
Authors: Fraudeau Robin ,   4DAtlantic-OHC Team
Published: February 2023

Given the major role of the Atlantic Ocean meridional heat transport in the climate system, it is essential to characterize its temporal variations at different locations. The 4DATLANTIC-OHC Project (https://eo4society.esa.int/projects/4datlantic-ohc/) aims at developing and testing space geodetic methods based on satellite altimetry and space gravimetry to estimate the local ocean heat content (OHC) changes over the Atlantic Ocean. Combined with independent estimates of the surface heat fluxes this approach holds promise to estimate the Atlantic Meridional Heat Transport (MHT) at any section across the Atlantic basin. The official version 1.0 of the 4DAtlantic-OHC product has been released, it provides estimates of local changes in OHC with their uncertainties. This product is accessible with DOI https://doi.org/10.24400/527896/A01-2022.012  and can be downloaded on AVISO portal. At two test sites, OHC changes derived from in situ data (RAPID and OVIDE) are used to evaluate the accuracy and reliability of the new space geodetic based OHC change estimate. Combined with ERA5 estimate of the surface heat fluxes, the Atlantic OHC product will be used to derive an energy budget of the North Atlantic basin and estimate the associated divergence in ocean heat transport. From the divergence field we will derive at the end of the project new estimates of the Atlantic meridional heat transport at different sections in the North Atlantic basin (RAPID and OSNAP sections) and compare it with in situ estimates. The V1.0 of 4DAtlantic-OHC products over the Atlantic Ocean, the evaluation results of the OHC against in situ data and preliminary results of MHT estimation will be presented.
ESA DataLabs: an open science platform relevant to Heliophysics
Authors: Masson Arnaud , Merin Bruno , Navarro Vicente , Arviset Christophe , Middleton Helen
Published: February 2023

ESA Datalabs is a collaborative scientific platform of the European Space Agency to exploit data across the ESA science directorate missions’ archives (astronomy, planetary and heliophysics). It allows you to bring your code to the data under a private account, shareable with colleagues. Large amount of data such as the GAIA multi-billion stars catalogues can be easily mounted and searchable, allowing large scale scientific investigations impossible to achieve on a regular laptop. It also provides multiple tools to access, process and visualize JWST data and was used during the recent commissioning of JWST. In other words, it handles both public and restricted access data.In the heliophysics domain, data from a few missions are already mounted, including all public data from the Solar Orbiter mission. A few Jupyter notebooks are already available to help the community making use of the full capabilities of the ESA archives. More will be made available in the future including tools such as JHelioviewer and data mining. Interoperability is at the heart of the ESA datalabs infrastructure and connection to clouds such as the NASA heliocloud and Amazon Web Services accounts (AWS) are in progress. Developed over the past few years, ESA Datalabs is scheduled to be public to the scientific community in 2023. 
Analysis of the recharge process of Alpine Spring through an integrated approach: the case of Perrot spring (Aosta Valley, Italy)
Authors: Santillan Quiroga Luis Miguel , Cocca Daniele , Marchina Chiara , Lasagna Manuela , Destefanis Enrico , Vescovo Giacomo , Bolognini Davide , De Luca Domenico Antonio
Published: February 2023

The Perrot spring (1305 m a.s.l.), located on the right side of the Chalamy Stream, inside the Monte Avic Natural Park (Aosta Valley, NW Italy), is an important source of drinking water for Champdepraz municipality.The spring is placed on a large slope characterized by the presence of debris covers of various origin (glacial, fluvial and landslide) above the bedrock (serpentinised peridotites and metabasites of the Zermatt-Saas Zone, Penninic Domain) which crops out only in the upper part of the basin.The water source is fed by rainwater infiltrating and flowing into the shallow deposits, with a permeability by porosity, and into the most fractured portion of the substrate. The water emerges at the contact between the topographic surface and impermeable or semi-permeable basal lithologies (unfractured crystalline rocks and glacio-lacustrine deposits).The aim of this study is to delineate the recharge processes of the spring and the definition of the recharge area extension that is very important for its conservation.In this view, an analysis of groundwater spring parameters (e.g. daily discharge, temperature and electrical conductivity) were conducted for the years 2018-2020.The flow rate ranges between 22 and 47 L/s with two maxima, one in spring and one in autumn; the electrolytic conductivity varies between 60 and 75 S/cm. The variation of groundwater temperature is very low, between 4.9°C and 5.5°C.  The low discharge and temperature variations suggest a relatively high average share of the supply area and a sufficiently deep flow circuit.The analysis of these data shows the presence of two contributions to the spring supply: a spring contribution from snowmelt, characterized by a low INCREASE in flow rate, and an autumn contribution from rainwater infiltration.Moreover, sampling campaigns were also carried out in the entire Chalamy stream basin in August 2021 and January, July, September 2022. In particular, water from lakes, rivers, spring and rainwater was sampled.During the field campaigns, pH, electrical conductivity and temperature were measured in situ. Chemical analysis of major ions and stable isotopes (δ2H and δ18O) were then conducted on water samples.The chemical analyses show a groundwater chemistry coherent with the regional geology: the hydrochemical facies is bicarbonate-sodium, the main cations are Ca2+ and Mg2+ and the anions HCO3-.  Finally, isotopic analyses of precipitation and spring water suggest a recharge elevation of around 2,500 m a.s.l.
Evaluation of soil indicators for agriculture in The Netherlands
Authors: Hanegraaf Marjoleine , de Haan Janjo , Vervuurt Wieke , Schnabel Sabine , Van den Elsen Erik , Visser Saskia
Published: February 2023

Since soil health is considered important for both agriculture production and climate change, there is growing consensus on the selection of relevant soil indicators. However, reference and/or target values to evaluate the indicators are poorly defined. We designed a system for a uniform and integral evaluation of soil quality. The system (named BLN) supports the Dutch aims for sustainable management of agricultural soils by 2030 and annual sequestration of 0.5 x 106 kg carbon. BLN consists of a set of soil health indicators and corresponding reference values for assessing ecosystem services, e.g. carbon sequestration, bulk density, and microbial biomass. Pre-selected features of BLN are: i) give a reliable representation of integral soil quality, ii) able to detect changes in soil quality in time and space, iii) applicable for national and/or regional regulatory monitoring purposes as well as field and/or farm management. Indicators and analytical methods were selected on the basis of accuracy, reliability, rapidity, and cost-effectiveness. Initial reference and/or target values were taken from a national survey and from literature. The system distinguishes reference and target values ​​for four different soil type / land use combinations. BLN Version 1.1 comprises 18 indicators for soil organic matter, chemical, physical and/or biological aspects of soil health, many of which are from routine soil analysis. To test its use, BLN was applied within a network of arable farms covering the major arable regions in The Netherlands. Soil samples were taken in autumn 2019, 2021 and 2022 and analysed for BLN and other soil parameters e.g. disease suppressiveness. Also, details of annual soil and farm management since 2010 were registered, as well as regional climate statistics. Data-analyses include change over time for individual indicators, PCA-analysis with all measured indicators, and, for soil carbon, modelling with the ROTHC-model. Results will be discussed viz. a multi-criteria approach for further development of the BLN system, including possible improvement of reference / target values as well as extension of the system with other soil type / land use combinations.
Audit and prevention in the jurisprudence of the Italian Court of Auditors
Authors: Fratto Rosi Grippaudo Emanuele
Published: February 2023

This contribution aims at delving into the ways in which the Italian Court of Auditors avoids the risk of irregularities that may affect the economic performance of budgets approved by local authorities. It also aims at analysing the role of the Italian Court of Auditors in addressing the non-compliance with parameters of financial legality. These objectives will be reached through an analysis of current Italian legislation and its interpretation by the Italian Court of Auditors. First of all, this contribution will propose an expansion of the concept of jurisprudence of the Italian Court of Auditors, which also includes the deliberations of the regional audit departments of the abovementioned Court. In particular, it will be argued that these decisions are the result of the integration of judicial and audit activities and, a positive view will be taken towards the possibility of a substantial assimilation with judicial measures. Secondly, this contribution will build upon legislative texts and decisions enacted by the Italian Court of Auditors in order to establish the rules governing the audit activity on the financial management of local authorities, which is undertaken by the regional sections of the abovementioned Court. In particular, this contribution will focus on the rules aimed at avoiding or mitigating the risk of failure to reach a balanced budget. Moreover, this contribution will examine the sanctioning activity of the Italian Court of Auditors, which is addressed both to local authorities and their administrators. This sanctioning activity is aimed at preventing specific risks, which undermine the financial stability of local authorities. In conclusion, this contribution will argue that the Italian Court of Auditors has an effective set of tools to prevent risks and deal with emergencies related to the accountancy of local authorities and will call upon the legislators to intervene in an area of accounting law dominated by the interpretative choices of the abovementioned Court.
Plasma mixing during active Kelvin-Helmholtz instability at the Earth’s magnetopause under different interplanetary magnetic field configurations
Authors: Settino Adriana , Nakamura Rumi , Blasl Kevin A. , Nakamura Takuma , Perrone Denise , Valentini Francesco , Roberts Owen Wyn , Panov Evgeny , Vörös Zoltan , Volwerk Martin , Schmid Daniel , Hosner Martin , Graham Daniel B. , Khotyaintsev Yuri V.
Published: February 2023

The Kelvin-Helmholtz (KH) instability is a shear-driven instability commonly observed at the Earth’s magnetopause under different solar wind conditions. The evolution of the KH instability is characterised by the nonlinear coupling of different modes, which tend to generate smaller and smaller vortices along the shear layer. Such a process leads to the conversion of energy due to the large-scale motion of the shear flow into heat contributing to the local heating and the generation of a turbulent environment. On the other hand, it allows the entry of the dense and cold solar wind plasma into the tenuous and hot magnetosphere, thus favoring the mixing of these two different regions.In this context, we introduce a new quantity, the so-called mixing parameter, which can identify the vortex boundaries and distinguish among different types of KH structures crossed by the spacecraft. The mixing parameter exploits the well distinct particle energies which characterise the magnetosphere and magnetosheath plasmas by using only single-spacecraft measurements [1]. The mixing parameter is therefore used to conduct a statistical analysis of the evolution of KH structures observed by the Magnetospheric Multiscale mission in the near Earth’s environment for two specific interplanetary magnetic field configurations: northward and southward. Moreover, in situ measurements are compared with kinetic KH instability simulations modeling realistic conditions observed by the satellites. The good agreement between synthetic data and in situ observations further strengthen our interpretation of the mixing parameter features and results. [1] Settino, A., et al. (2022) Journal of Geophysical Research: Space Physics, 127, e2021JA029758.
An innovative method to determine springs recharge areas by using water isotopes: intuitions from mountain hydrogeological studies in central Italy
Authors: Fronzi Davide , Palpacelli Stefano , Marcellini Mirco , Massari Christian , Tazioli Alberto
Published: February 2023

Over the years the scientific community underlined several problems related to the use of isotopic hydrology techniques in areas characterized by a complex orography, usually occurring in mountain areas, or in those cases where the hydrological setting is complicated by contacts between different aquifers (Nanni et al., 2013).In this study, an innovative isotopic model, able to identify the most probable recharge area for several springs exploited for drinking purposes, has been developed and applied to the Nera catchment in the Sibillini Mountain National Park (central Italy). The isotopic investigation consists of a preliminary definition of a new δ18O - elevation relationship, considering the morphological and meteorological heterogeneities within the area and their possible influences on the precipitation isotope values (e.g., shaded areas, snow drift effect, etc.). Second, an advanced δ18O distribution model, supported by statistical and GIS-based procedures, has been implemented by clipping the precipitation δ18O values (depicted from the δ18O – elevation relationship) over an upstream area for each analyzed spring. The new isotopic modeling approach can be conveniently applied if the infiltration rate of the meteoric water is fast enough to avoid fractionation processes that may alter the isotopic signal of the precipitation input within the aquifer, and if peculiar meteoric recharge phenomena, altering the springs' isotopic signal, are treated as outliers.This research highlights if the most used isotopic approach based on the determination of groundwater recharge areas starting from δ18O - elevation gradient (Jeelani et al., 2010; Jasechko, 2019) applied to a selected spring isotopic data agrees with the hydrogeological setting of the spring recharge area which is often complicated by the topography and the contacts between different aquifers both for stratigraphic and tectonic reasons.The ultimate goal of this study is to quantify the aquifers recharge under the impact of drought to improve the water resources management operations in the area.