bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping glacier basal sliding applying machine learning
Authors: Umlauft Josefine , Johnson Christopher Whilliam , Roux Philippe , Trugman Daniel Taylor , Lecointre Albanne , Walpersdorf Andrea , Nanni Ugo , Gimbert Florent , Rouet-Leduc Bertrand , Hulbert Claudia , Johnson Paul Allan
Published: February 2023

During the RESOLVE project ("High-resolution imaging in subsurface geophysics: development of a multi-instrument platform for interdisciplinary research"), continuous surface displacement and seismic array observations were obtained on Glacier d'Argentière in the French Alps for 35 days during May in 2018. This unique data set offers the chance to perform a detailed, local study of targeted processes within the highly dynamic cryospheric environment. In particular, the physical processes controlling glacial basal motion are poorly understood and remain challenging to observe directly. Especially in the Alpine region for temperate based glaciers where the ice rapidly responds to changing climatic conditions and thus, processes are strongly intermittent in time and heterogeneous in space. Spatially dense seismic and GPS measurements are analyzed with machine learning techniques to gain insight into the underlying processes controlling glacial motions of Glacier d'Argentière.Using multiple bandpass-filtered copies of the continuous seismic waveforms, we compute energy-based features, develop a matched field beamforming catalogue and include meteorological observations.Features describing the data are analyzed with a gradient boosting decision tree model to directly estimate the GPS displacements from the seismic records.We posit that features of the seismic noise provide direct access to the dominant parameters that drive displacement on the highly variable and unsteady surface of the glacier. The machine learning model infers daily fluctuations as well as longer term trends and the results show on-ice displacement rates are strongly modulated by activity at the base of the glacier. The techniques presented provide a new approach to study glacial basal sliding and discover its full complexity.
Improvements in the estimation of glacier surface mass balance taking into account albedo decay parameters
Authors: Calleja Javier , Muñiz Rubén , Navarro Francisco , Otero Jaime , Fernández Susana
Published: February 2023

The search for satellite-derived proxies of the surface mass balance (SMB) of glaciers is of crucial importance for an updated estimation of the SMB worldwide. The minimum mean  glacier albedo (αmin, calculated as the minimum mean albedo over the whole glacier) attained along a season has proved to be a good proxy. In this work we demonstrate that SMB estimations can be improved by adding albedo decay parameters as predicting variables. The SMB of Hurd glacier (Livingston Island, Antarctica) has been continuously monitored since 2001, with available values of annual, summer and winter SMB. MODIS MOD10A1 daily snow albedo product with a spatial resolution of 500 m over the glacier was downloaded using the Google Earth Engine Application Programming Interface. Data from 2000-2001 to 2020-2021 season are considered in this work. MOD10A1 data were filtered using a maximum filter followed by a first-order Butterworth filter. Each season extends from September to March of two consecutive years. The seasonal albedo was fitted to an exponential decay α=αm+Aexp(-βt), and parameters αm, A and β as well as the albedo decay duration (D) were calculated for all pixels. Mean values of αm, β, A and D were calculated over the whole glacier. Monthly and seasonal mean αmin were also estimated from MOD10A1 data. Simple linear regressions show that the minimum albedo in the period January-February explains the summer SMB, while the minimum albedo in the period December-January explains the annual SMB. Multiple linear regression models including snow albedo decay parameters improve the quality of the models, increasing the value of the coefficient of determination and decreasing the root mean square difference between measured and predicted SMB. These results show that the SMB is determined not only by αmin but also by how fast and for how long the albedo decay takes place, and by the difference between the minimum albedo and the surface albedo at the beginning of the season. On the other hand, most of the snow albedo decay takes place in the period from late September to December. Previous investigations of mass balance over the Hurd Peninsula have established that the snow melt in Hurd Peninsula takes place mostly from December to March. The fact that snow melting lags behind albedo decay can be explained if we consider that some surface snow metamorphic processes occur prior to melting and that melting continues after surface snow has attained its maximum degree of metamorphism.
Development of a merged HCHO climate data record from the EUMETSAT AC SAF GOME-2 Level-2 products
Authors: De Smedt Isabelle , Pinardi Gaia , Valks Pieter , Heue Klaus-Peter , Compernolle Steven , Van Gent Jeroen , Vlietinck Jonas , Yu Huan , Loyola Diego , Theys Nicolas , Van Roozendael Michel
Published: February 2023

Within the framework of the EUMETSAT AC SAF project, the production of climate data records (CDRs) of short lived O3 precursors (HCHO and NO2) is under development, based on the three GOME-2 instruments and the future S5 and S4 Copernicus platforms.This work presents the development of the formaldehyde CDR, combining the current GOME-2 A, B and C operational AC SAF Level-2 orbital products to create one single L3 averaged product using advanced gridding tools. To this aim, the consistency between the three GOME-2 instrument needs to be improved by means of suitable correction schemes accounting for inter-sensor biases due to inconsistent auxiliary data or instrumental issues. The use of the CAMS model reanalysis as a source of prior HCHO profiles is explored with the aim to produce one consistent dataset from 2007 to now. Estimation of the random and systematic uncertainty is included for each grid cell. Furthermore, we plan to include meteorological re-analysis data (surface temperature and winds) in the output files to further support the interpretation of the data and of their observed variations.Validation results of this new monthly averaged CDR dataset will be presented, with a special focus on bias, precision and stability in time. To this aim, long-term ground-based HCHO measurements are collected and assessed.
The mass balance constraints on the depletion of elements during metamorphic devolatilization and anatexis
Authors: Stepanov Aleksandr
Published: February 2023

The consideration of mass balance to loss of elements from metamorphic rocks during devolatilization and anatexis reveals some principal constraints that must be considered in any model of element redistribution in metamorphic processes. During devolatilization, the changes in rock composition with the increase of metamorphic grade are a result of loss of fluid, produced by devolatilization reactions. Fluid, characterised by low viscosity and density, can be effectively extracted from a rock. Metamorphic devolatilization on average results in loss of 1-4 wt. % of the rock mass to the fluid and typically the average loss is <2 wt. %. This relatively small mass fraction mandates that in order to decrease the content of an element significantly (small percentage loss will not be visible on sediment heterogeneity) the concentration of an element in fluids must be much greater than in the protolith. For example, for 50% extraction of an element by 2% fluid, the fluid should have 25 times higher content than the protolith and loss of 50% of element with 0.5% of fluid require fluid with 100 times enrichment (Stepanov 2021).Anatexis produce granitic melt with high viscosity and density lower than restite. The experimental data suggest that melt extraction could occur when melting degrees >10%. For a completely incompatible element enrichment by 10 times relative to protolith could is maximum achievable in anatectic process. Many elements are concentrated in residual phases and completely incompatible behaviour is rarely observed, hence reducing the efficiency of enrichment. The closes examples of incompatible behaviour during anatexis are restites produced by high-T anatexis, when accessory minerals experienced complete dissolution in melt, such as restites of the Kokchetav complex and septa from Ivrea Verbano Zone (Ewing et al., 2014). However, higher melting degree produce less enriched melt even for incompatible elements. For compatible element melt loss increase content in restite, but loss of 10% melt increase only by 11%, and 50% of melt loss (which could be considered as maximum) increase incompatible element by factor of 2. The mass balance constraints show limits of the possible effect of fluid/melt loss on rock composition and suggests that fluid loss could produce higher enrichment factors than melt loss.ReferencesStepanov A.S., A review of the geochemical changes occurring during metamorphic devolatilization of metasedimentary rocks. Chemical Geology, 568 v, 120080, 2021.Ewing, T.A., Rubatto, D., Hermann, J., 2014. Hafnium isotopes and Zr/Hf of rutile and zircon from lower crustal metapelites (Ivrea–Verbano Zone, Italy): Implications for chemical differentiation of the crust. Earth and Planetary Science Letters 389, 106–118.
A fast algorithm for real-time monitoring of artificial radioisotopes in presence of variable natural radioactivity
Authors: Cerezo Agustín , Prieto Elena , Reichardt Ignasi , Casanovas Ramón , Salvadó Marçal
Published: February 2023

The Catalan Environmental Radiological Surveillance Network consists of different types of scintillation gamma spectrometry detectors for the continuous and real-time automatic measurement of environmental radiation. The Network has a total of 35 monitors that obtain spectra every 10 minutes: 23 direct measurement monitors (13 with LaBr3(Ce), 5 SrI2(Eu) and 5 NaI (Tl) detectors), 10 particulate filter monitors (9 with LaBr3(Ce) detectors and 1 with SrI2(Eu)) and 2 river water monitors.A method for the automatic and real-time quantification of the activity concentration of artificial, natural and NORM isotopes was developed and tested in the laboratory. The uncertainties in the activity concentrations, as well as the corresponding detection limits, were calculated applying the ISO-11929 standard. The developed and validated method that is exposed in the present study will be implemented shortly in all the stations of the Network.The method is based on the analysis by spectral regions or ROIs (Regions of Interest). The method eliminates from the ROIs of the artificial (or NORM) isotopes of study the contributions due to emissions of natural isotopes (overlapping and Compton radiation), the ambient background, the possible intrinsic background of the detector and the contributions of other possible isotopes. As a result, an equation is generated for each isotope that allows us to obtain its net activity concentration (Bq/m3). This procedure is applied to determine the activity concentration of isotopes of natural origin (212Pb, 214Pb and 214Bi), artificial (131I, 137Cs and 60Co) and NORM (234Th).The method successfully eliminates the contribution of natural elements, intrinsic background and Compton contribution, both in situations with high and low activity of natural isotopes. Therefore, it allows obtaining the net activity concentration of the artificial isotopes of interest and eliminates the presence of false positives that could be produced by the presence of natural isotopes.
Current potential of CH4 emission estimates using TROPOMI in the Middle East
Authors: Liu Mengyao , van der A Ronald , van Weele Michiel , Eskes Henk , Veefkind Pepijn , Zhang Xin , Kang Hanqing , Ding Jieying
Published: February 2023

Methane (CH4) is the second most important greenhouse gas after CO2. The TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel 5 Precursor (S5-P) satellite measures CH4 at a high horizontal resolution of 7 × 7 km2, showing the capability on identifying and quantifying the sources at a local to regional scale. The Middle East is one of the strong CH4-emitting regions in the world. However, it is difficult to estimate the emissions here because of the uncertainties caused by bright surfaces and high aerosol loadings. Furthermore, several sources are located near the coast or in places with complex topography, where satellite observations are often of reduced quality. We use the product from the University of Bremen, WMF-DOAS XCH4 v1.8 product, which has good spatial coverage over the ocean and mountains, to estimate the emissions in the Middle East. The Aerosol Optical Depth (AOD) data from the MODIS/Aqua satellite instrument, which has a similar overpass time as TROPOMI, was adopted to filter potential unreliable XCH4 in the product.For the inversion, we use the divergence method of Liu et al., (2021), which has been proven to be a fast and efficient way to estimate CH4 emissions from satellite observations. We have improved our method by comparing the fluxes in different directions for better background corrections over areas with complicated topographies. The temporal filter was established to further filter false emissions caused by surface albedos. We derived CH4 emissions on a grid of 0.2° from 2018 to 2021 and compared them to the latest bottom-up inventory EDGAR v7.0 in the same years. We found significantly lower emissions than EDGAR for the locations that are mainly determined by observed gas-flaring from satellites. Apart from sources of oil/gas production, the emissions from livestock in Saudi Arabia's irrigation zones, which have been reported neither in EDGAR nor other previous studies, are identified and quantified by using our divergence method. Another unexpected finding is that emissions from landfills are fairly stable and strong in some cities like Tehran.
Fate of Fire altered Organic Carbon in the arctic river-to-ocean continuum: Resolving Mackenzie River Black Carbon in the Beaufort Sea
Authors: Speidel Linn G. , Bröder Lisa , Lattaud Julie , Haghipour Negar , Eglinton Timothy I. , Coppola Alysha I.
Published: February 2023

Keywords: Black carbon, Dissolved organic carbon, BPCAs, Mackenzie River, Beaufort Sea, Climate changeClimate change is amplified in the arctic and boreal regions. This causes higher average temperatures and less precipitation in the summer months and is resulting in longer wildfire seasons, severity, frequency and extent. This increases the relies of carbon into the atmosphere as greenhouse gases and aerosols, amplifying climate change even further. Black carbon (BC) is a fraction of organic carbon, resulting from the incomplete combustion of biomass and fossil fuels. BC may be inaccessible for biodegradation, because of its highly condensed aromatic molecular structure and therefore stores carbon on long timescales on land and in the ocean. BC is produced on land, but is transported as dissolved BC (DBC) by the rivers to the oceans, where it cycles on millennial timescales, sequestering BC. Thus, it is important to understand the significance of BC in the context of increased fires in this vulnerable region in the face of climate change.The Mackenzie River is a major source of terrestrial dissolved organic carbon (DOC) and the largest source of sediments to the Arctic Ocean. Here, we resolve the cycling of riverine DBC from the Mackenzie River to its fate in the Beaufort Sea, and the influence of mixing with Pacific water masses entering from the Chukchi Sea. We present DBC concentration data in ocean water, which was collected on two cruises in the Beaufort Sea in 2021 and 2022 covering the outflow of the Mackenzie River.For DBC concentrations, we digested solid phase extracts of DOC with nitric acid to oxidize BC molecules into benzenepolycarboxylic acids (BPCAs), which were then quantified on High Performance Liquid Chromatography (HPLC). We compare the concentrations of the DBC and DOC to trace the mixing of DBC river outflow with the ocean water. Since DBC originates on land and is relatively stable to biodegradation we can resolve the pathways of DBC from the Mackenzie River to the Arctic Ocean.  
Towards a robust parameterization of subsurface stormflow in hydrological models at the catchment scale
Authors: Leins Tamara , Pianosi Francesca , Hartmann Andreas
Published: February 2023

In addition to overland flow, subsurface stormflow (SSF) can play a major role for runoff generation during certain events. Even though SSF is a well-recognised process, there is a lack of systematic studies on SSF, partly because it is very difficult to quantify. In hydrological modelling, this can lead to an unclear distinction of SSF from other processes. If parameters that describe SSF processes or thresholds are implemented in hydrological models, they are often used as fitting parameters and can contribute to overall model uncertainty. So far, there has been no systematic benchmarking of SSF routines in hydrological models.This presentation discusses how we plan to address this research gap. In order to address the inconsistency of SSF representation in hydrological models, different existing lumped hydrological models will be set up for four study sites located in the Alps, Ore Mountains, Black Forest and Sauerland. In a first step, different models will be calibrated using only basic data like discharge observations, climate data and readily available geodata. Differences in SSF simulations will be detected and quantified and the models will be benchmarked regarding the simulation of SSF dynamics and associated uncertainties. In a next step, we will include new experimental data on SSF derived at the four study sites in the calibration of the lumped hydrological models by a multi-objective calibration and evaluation framework. In order to consider SSF observations collected at scales different than the scale of model application, new SSF metrics will be developed. Testing different combinations of these metrics for model calibration it will be possible to state which SSF proxies can lead to the most productive improvement of SSF simulations.Identifying current weaknesses in SSF representation of current models, and providing directions for improving them by including the most beneficial SSF metrics, this project will show potential for the improvement of SSF simulations through SSF data collection. In a final application of the most reliable SSF simulations to all study sites, we will show the impact of extreme wet or extreme dry conditions on SSF occurrence and SSF volumes.
Interactions between meteorological and agricultural droughts at different temporal and spatial scales
Authors: oukaddour kaoutar , Fakir Younes , Le Page Michel
Published: February 2023

The Tensift basin is prone to drought and, with the increasing frequency of extreme events, their forecasting and monitoring are becoming more complex. The present work aims to shed light on the interactions between meteorological and agricultural droughts while using multiple drought indices, and analyzing its temporal and spatial patterns over the Tensift basin in Morocco. To this purpose, we initially performed a trend analysis of the main parameters used in this study namely precipitation, temperature, NDVI, and soil moisture using the Mann-Kendall test. Moreover, a data-driven approach was adopted here to reveal the impact of lack of precipitation on the soil and vegetation cycles. Remote sensing data of precipitation from ERA5Land and soil moisture data from ESA-CCI as well as land surface temperature and NDVI from MODIS are used to calculate the standardized precipitation index (SPI), the vegetation condition index (VCI), the temperature condition index (TCI), and the soil moisture condition index (SMCI) for the period 2001–2021. A comparison analysis was conducted to test the performance and concordance of the indices. Then, to analyze the propagation of meteorological drought to the other components we conducted a cross-correlation study between drought indices.  The results reveal an upward trend of NDVI which is noticeable from the first decade (2009) and is attributed to the development of irrigated areas in this period. In contrast, the basin has shown a significant decline in monthly soil moisture for the period extending from 2001 to 2021, which could be explained by the way how soil moisture is retrieved in the ESA CCI product, and the trend in vegetation. On the other hand, the monthly precipitation and land surface temperature time series show no significant trend. The comparison between the indices showed moderate to low agreement. Correlations between TCI and SPI were eventually negative and significant at small time scales. A moderate correlation was observed between SPI1, SPI3, and TCI (0.45). The strongest correlations between SMCI and SPI were found at the 3 and 6-month time scales. Furthermore, the concordance between VCI and SPI is stronger at larger SPI time scales, the best correlation was observed between the indices VCI and SPI at 12 months with a correlation coefficient of 0.44. The correlations in the Tensift basin reflect spatial heterogeneities where some indices are more prevailing than others. Lag analysis results demonstrate valuable insights into the leading and preceding behavior of different variables regarding SPI. Relevant responses were identified at short, mid, and long-term influence of precipitation deficits on soil moisture, vegetation, and temperature. The results of this study highlight the interest in analyzing drought with different indices dedicated to each type of drought in order to improve early warning systems and risk management strategies for semi-arid areas.
Simulation of GNSS observations for Genesis-
Authors: Bury Grzegorz , Arnold Daniel , Dach Rolf , Jäggi Adrian
Published: February 2023

A global Terrestrial Reference Frame (TRF) is realized today by four space geodetic techniques, i.e., Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). The current goals for the TRF realization are specified with an accuracy of 1 mm and long-term stability of 0.1 mm/year according to the Global Geodetic Observing System requirements.Differences in the characteristics of each space geodetic technique might introduce systematic effects into TRF realization. Among the crucial systematics, we can distinguish modeling and calibration deficiencies, i.e., direct solar radiation pressure (SRP) modeling for GNSS and DORIS, GNSS antenna calibration uncertainties, South Atlantic Anomaly handling for DORIS, and time and range bias handling for SLR. The current realization of the TRF is based on independent solutions for each of the four contributing space geodetic techniques that are just connected on the ground via local ties and the Earth Rotation Parameters. A new opportunity to challenge the systematic errors is to co-locate space techniques onboard one satellite, as it is planned for the Genesis-1 mission. The Genesis-1 satellite is the first ever satellite co-locating sensors related to GNSS, SLR, DORIS, and VLBI.In this study, we present preliminary results for orbit reconstruction using simulated GNSS observations for the Genesis-1 satellite. We use the Bernese GNSS Software for different orbital altitudes, including the currently planned altitude of 6000 km. We assess the quality of the orbit reconstruction using simulated GNSS data from observations of the zenith-, nadir-, and both zenith and nadir-looking antennas. Additionally, we assess the visibility from the ground tracking network of VLBI, SLR, and DORIS, for the different satellite altitudes.
Attenuation of mountain-valley winds on wintertime PM2.5 change over the western Sichuan Basin, Southwest China
Authors: Zhang Yuqing , Zhao Tianliang , Shu Zhuozhi , Zhu Yan , Fu Weikang , Liang Dingyuan
Published: February 2023

The Sichuan Basin (SCB) with complex mountain-basin topography, located immediately to the east of the Tibetan Plateau (TP) in southwest China, is identified as a region with severe PM2.5 pollution over China. To comprehensively understand the SCB terrain effect on the atmospheric environment change, we investigated the effect degree and meteorological mechanism of mountain-valley winds on wintertime PM2.5 in the western SCB, thermally driven mountain-valley winds between the mountains of eastern TP and the western edge of SCB based on near-surface observations of PM2.5 and the ERA5 reanalysis data of meteorology. The results show that the western SCB exhibits a significant diurnal change of mountain-valley winds, shifting between daytime easterly flows and nighttime westerly flows over the western edge of SCB. The frequency of the mountain-valley winds was accounted for 39% of the study’s duration, with the valley and mountain wind-controlling periods being from 2:00 pm to 5:00 pm and 01:00 am to 05:00 am in local time, respectively, and the remaining time being the transition period. Notably, a reduction of 4.5~20.7μg m-3 in near-surface PM2.5 concentrations averaged over the western edge of SCB, decreasing 6~74% in the PM2.5 pollution during the days of mountain-valley winds, which indicates that the mountain-valley winds could alleviate wintertime near-surface PM2.5 in improving air quality over the western SCB. The easterly wind speed was uplifted by 18% during the valley wind-controlling period, corresponding to a 22% reduction in the near-surface PM2.5 levels driven by the mountain-valley winds. The westerly wind speed increased by 50% at the mountain wind-controlling period with a 20% reduction in PM2.5, reflecting the attenuating effect of the favorable atmospheric diffusion conditions on PM2.5 pollution over the western SCB. The daytime noticeably enhanced easterly wind and the strong updraft flows over the eastern slope of TP promoted the dilution and diffusion of air pollutants over the western edge of SCB, and the nocturnal downhill flows along the slope in the westerly winds on the western edge of SCB brought clean TP air to the polluted SCB region in southwest China.
Lithium incorporation and isotopic fractionation in large benthic foraminifera under decoupled pH/DIC conditions
Authors: Charrieau Laurie , Rollion-Bard Claire , Terbrueggen Anja , Wilson David , Pogge von Strandmann Philip , Misra Sambuddha , Bijma Jelle
Published: February 2023

The chemical weathering of continental silicate rocks removes CO2 from the atmosphere and exerts a fundamental control on the Earth’s climate over geological timescales. Characterizing silicate weathering in the past is therefore crucial for understanding the climate system. The lithium isotopic composition (δ7Li) of carbonates is considered to be a reliable archive of past seawater δ7Li values, which are useful as a tracer of silicate weathering. However, the Li isotopic fractionation during biogenic carbonate formation is complex, and local conditions such as carbonate system parameters could impact δ7Li values in marine calcifiers. For example, δ7Li values have been shown to be dependent on either pH or DIC in two studies using large benthic foraminifera. Those results are enigmatic, since both studies used similar species of the genus Amphistegina but reported differing controls on δ7Li values.The aim of this study was to address the earlier contradictory results on the Li isotope behaviour in the hyaline species Amphistegina lessonii. We performed culture experiments under decoupled pH/DIC conditions, and analysed the δ7Li values and Li/Ca ratios in the foraminifera tests. Two different light treatments (light/dark and dark) were also implemented to investigate the potential role of the symbionts.Contrary to the two previous studies, no links between either pH or DIC and δ7Li or Li/Ca values were observed for any of the treatments in our experiments. Additionally, growth rates also did not seem to influence the Li incorporation or isotopic fractionation. However, an effect of different light treatments was observed, probably due to different physiological processes of the symbionts occurring in dark conditions. Overall, these findings appear to support the use of Li isotopes in large benthic foraminifera to reconstruct past seawater chemistry and to infer changes in chemical weathering during carbon cycle perturbations over the last several hundred million years of Earth history.
Sources of cave CO2 at Milandre cave, Switzerland constrained through multipool analysis of 14C and δ13C.
Authors: Rowan Sarah , Luetscher Marc , Szidat Sönke , Laemmel Thomas , Kost Oliver , Lechleitner Franziska
Published: February 2023

The cycling of subsurface karst CO2 is not well constrained in terms of its source and transportation pathway. The classical model suggests that cave CO2 is produced by the respiration of soils and vegetation in the catchment. In contrast, several new studies have proposed that the dominant source of CO2 is from the respiration of older organic matter situated deeper within the karst, or from the degassing of supersaturated drip water.We present over a year of monitoring data from Milandre cave, northern Switzerland, whereby we evaluated the 14CO2 and δ13CO2 composition of the atmosphere in the cave catchment, catchment soil gas, well gas, and cave air. Drip waters located throughout the cave also underwent various analysis. The cave 14CO2 is more depleted compared to the soil and gas samples. The Keeling plot intercept of atmospheric and cave δ13CO2 is ~-26‰, indicating a dominant contribution from biological respiration. The dissolved inorganic carbon from various cave drips have an F14C from ~ 0.84 to 0.96 and δ13C from ~ -16‰ to -11‰. F14C and δ13C are inversely correlated.  Considering both the 14C and δ 13C results, this suggests either a source of CO2 from an aged reservoir of respiring organic matter contributing to the cave gas or substantial influence from degassing of 14C fossil carbonate CO2 from drip water. These results have implications for the understanding of the subterranean carbon cycle and the interpretation of speleothem carbon isotope records for paleoclimate studies.
Infrasonic signals collected in the water column close to Svalbard
Authors: Waldmann Christoph , Engler Christian
Published: February 2023

A measuring campaign for detecting infrasonic signals in the water column had been carried out in the vicinity of Svalbard in 2022 from board the research vessel Helmer Hanssen of the University of Tromsoe. The aim was to identify and classify signals that may have resulted from processes like collapsing glaciers or sediment slides on the islands or underwater. The summer months are of particular interest for those type of measurements as the geological structure of the archipelago gets instable in the summer months due to the melting of glaciers. As the measurement time was limited to a few hours for each campaign it is difficult to classify the infrasonic signals based on satellite measurements. Rather an attempt has been made to identify similar signals in seismic stations on Svalbard.

During one measurement cycle a characteristic signal has been detected that probably resulted from a glacier collapsing or sediment slide event. A basic model will be evaluated to explore whether it can serve as an explanation for the collected data. Additionally, results from an acoustic propagation model calculation for the low frequency signal will be presented which will provide an estimate of the distance of the observed event from the infrasound listening device. From the described analysis considerations in regard to future deployment configurations for infrasonic observations are derived.
Machine learning ensemble models for solar wind speed prediction
Authors: Sabbatini Federico , Grimani Catia
Published: February 2023

Machine learning models trained to reproduce space mission observations are precious resources to fill gaps of missing data in measurement time series or to perform data forecasting within a reasonable uncertainty degree. The latter option is of particular importance for future space missions that will not host instrumentation dedicated to interplanetary medium parameter monitoring. The future LISA mission for low-frequency gravitational wave detection, for instance, will benefit of particle detectors to measure the galactic cosmic-ray integral flux variations and magnetometers that will allow to monitor the passage of large scale magnetic structures through the three LISA spacecraft as part of a diagnostics subsystem. Unfortunately, no instruments dedicated to solar wind speed measurements will be present on board the spacecraft constellation. Moreover, LISA, scheduled to launch in 2035, will trail Earth on the ecliptic at 50 million km distance, far from the orbits of other space missions dedicated to the interplanetary medium monitoring.Based on precious lessons learned with LISA Pathfinder, the ESA LISA precursor mission, about the correlation between galactic cosmic-ray flux short-term variations and solar wind speed increases, we built a machine learning ensemble model able to reconstruct the solar wind trend only on the basis of contemporaneous and preceding observations of galactic cosmic-ray flux variations. Details about the model creation and performance will be presented, together with a description of the underlying data set, weak predictors and training phase. Advantages and limitations will be discussed, showing that the model performance may be enhanced by providing interplanetary magnetic field intensity observations as additional input data, with the goal of providing the LISA mission with an effective solar wind speed predictive tool.
Assessment of crop yield losses for Triticum aestivum in Punjab and Haryana using in-situ measurements, relay seeding experiments and the DO3SE model
Authors: Sinha Baerbel , Saha Sneha , Meena Aakanksha , Singh Sukhwinder , Kharra Pankaj , Adarsh Adarsh , Ashish Ashish , Anand Sanjay , Ram Kishore Yadav
Published: February 2023

Measurements of leaf-level stomatal conductance (gsto) are central to the ozone (O3) risk assessment as the allow to recorded environmental response functions that describe how a wheat cultivar responds to different environmental stressors. The calculation of Triticum aestivum yield loss based on the absorbed O3 phytotoxic dose over a threshold of y (PODy) has been introduced as a new way to conduct ozone  risk assessment. In this study we present environmental response functions of two triticum aestivum cultivars grown as irrigated winter wheat in the state of Punjab, in the North West Indo Gangetic Plain based on measurements conducted during winter 2016-17, 2017-18, and 2018-19. The cultivars PBW550 and HD2967 were directly obtained from breeders and were sown on November 15th in 2016-17 and 2017-18, and in a relay seeding experiment on November 1st, 15th and December 1st in 2018-19.We use meteorological observations and ozone measurements obtained at the Central Atmospheric Chemistry facility of IISER Mohali in Punjab, India between November 2016 and April 2019 to derive environmental response function for these two cultivars and estimate triticum aestivum relative yield losses and crop production losses due to ozone. We demonstrate that environmental response functions are not only useful to assess the impact of ozone on plant growth but that they can also be used to assess the impact of heat stress and climate change on yields. We show that modifying the phenology function used in the DO3SE assessment such that it incorporates the impact of heat stress experienced between anthesis to maturity permits a more accurate assessment of the impact of ozone on the wheat yield. We also demonstrate that a thermal time calculation method that is consistent with the temperature response function used in the DO3SE improves the quality of the assessment.We evaluate the impact of both heat stress and ozone exposure during different growth stages on several yield parameters including the number of active tillers, 1000-grain weight, flower sterility, number of shrivelled grains.Late sowing typically not only results into high thermal stress during sensitive growth stages, but also in higher ozone exposure. We find that PBW550 is more sensitive to stress during the grain filling stage than HD2967. However, for both cultivars moderate heat and ozone stress can be associated with superior rather than reduced yields in the real world. We explain this yield-loss yield paradox with the help of meteorological observations.
Influence of suspended sediment concentration on hyperpycnal delta progradation
Authors: Liang Yi-Yun , Su Chiun-Chau , Capart Hervé
Published: February 2023

When rivers with high suspended sediment load plunge into lakes and reservoirs, the resulting density currents often cause the formation and progradation of hyperpycnal deltas. Suspended load can contribute to delta progradation through two different mechanisms: (1) indirectly, by increasing the excess density of the underflows, thus enhancing the basal shear stresses that drive along-bed transport; (2) directly, by settling out of suspension onto the evolving bed. In this work, we conducted laboratory experiments designed to investigate the relative importance of these two mechanisms, aided by a conceptual model that includes both processes. The experiments are conducted in a narrow tank of constant slope, supplied with prescribed water, sediment, and/or saline influxes. Both suspended sediment load and salinity can therefore contribute independently to the excess density of the inflow. Simultaneous measurements of delta profile evolution and suspended sediment concentration are then acquired using imaging methods. To interpret the results, we construct a simplified one-dimensional model of delta progradation in which along-bed transport is modelled as a diffusion process, and suspended sediment settling as an advection-deposition process. We then examine the influence of process coefficients on the morphology and rate of evolution of the delta fronts and compare simulations with the experiments. It is found that the evolution of the bed profile alone is not sufficient to distinguish between the two mechanisms, hence the importance of simultaneously measuring suspended sediment concentration. Although obtained in a simplified setting and at reduced scale, the results should provide useful guidance for the modeling and monitoring of reservoir sedimentation at field scales.
Implementing the Krafla Magma Testbed (KMT): linking volcanology and geothermal research for future hazard and energy solutions
Authors: Lavallée Yan , Mortensen Anette , Papale Paolo , Eichelberger John , Sigmundsson Freysteinn , Kennedy Ben , Villeneuve Marlène , Jousset Philippe , Dingwell Donald Bruce , Markusson Sigurdur , Eiríksdóttir Vordís , Pálsson Bjarni , Tester Jeff , Karlsdóttir Sigrún Nanna , Midgley John , Ingolfsson Hjalti Páll , Ludden John
Published: February 2023

Driven by the need to understand magmatic systems, to improve volcano monitoring strategy, and to develop next-generation, high-enthalpy, geothermal energy, we introduce the Krafla Magma Testbed (KMT) – located in Northeast Iceland. KMT aims to establish the first magma observatory – an international, open access, scientific platform to advance ductile zone to magma research via drilling and novel sensor systems. This frontier undertaking will enable direct, in situ sampling, instrumentation and manipulation, and monitoring of magma and its interface with solid Earth’s crust, vastly advancing models of high-temperature crustal processes. This initiative is enabled by past geothermal drilling at Krafla volcano that was serendipitously intersected and thus determined the exact location of magma for the first time. This unprecedented experience, including safe control of the wells, provides the basis for KMT, which stands to transform modern volcanology and geothermic disciplines. KMT will develop a long-term infrastructure (>25 years) for the conduct of interdisciplinary scientific, engineering, technological, and educational activities. The Krafla volcano has the advantage of a long history of geological study, volcano monitoring, and drilling as well as supporting surface facilities combining to produce the safest and most efficient base from which to explore Earth beyond the solidus.  KMT will be the place to develop (1) our science of hot and molten Earth; (2) new ways of understanding and monitoring volcanoes; (3) our ability to extract and exploit geothermal energy sources; and (4) new technology and materials that function in the most extreme conditions in planetary systems. The value of potential gains in fundamental understanding of crustal processes is beyond our possibility to estimate. There is the prospect of an order of magnitude gain in geothermal energy productivity. The need to improve understanding of the source of catastrophic eruptions and to better forecast them is a compelling humanitarian one.
INTEGRATED DISASTER RISK MANAGEMENT (IDRiM) APPROACH FOR COASTAL AREAS USING PARTICIPATORY GIS: A CASE STUDY OF INDIAN SUNDARBANS
Authors: Laha Salui Chalantika
Published: February 2023

This work has implemented An Integrated Disaster Risk Management IDRiM approach on the disaster events of Indian Sundarbans, a world heritage site where the ecosystem and livelihood are threatened by frequent cyclonic disasters originating in Bay-of-Bengal. The inhabitants encounter tremendous economic losses as well as losses of lives due to direct cyclonic storms and the storm surge water flooding. In recent past, the forestry and aquaculture dependent economically backward inhabitants of Sundarbans experienced the devastating hit of Sidr (2007), Aila (2009), Phailin (2013), Hudhud (2014), Bulbul (2019), Amphan (2020), Yaas (2021), Sitrang (2022) which left them with severe losses.  The habitants started to change their work pattern and intended to migrate toward the mainland. Land use / land cover also changed with some changing scenario of the mangrove ecosystem.All these adverse effects of the coastal cyclonic events claim the need for a proper and effective disaster damage reduction plan. Here, the proposal has been given to formulate a web-enabled platform for near real-time cyclonic path and surge height prediction and rescue and rehabilitation planning with the stakeholders to make the execution effective and successful. This is a platform where; various government departments will update the cyclone related earth observation and hydro-meteorological data on near real-time basis during the emergency period. Ground information and infrastructural spatial database are to be regularly updated by the concerned departments. The access to the platform will be secured to the planners and stakeholders whereas a selective accessibility can be allowed for the community people for community awareness and live situation tracking. The purpose is to minimize the loss as much as possible by taking prompt actions by the administration. The platform also helps to monitor the disaster preventive measures with the hand-to-hand cooperation of local people and administration. In some cases, administration needs the authentication of the relief claims which can increase the transparency of the government strategies and schemes. Rehabilitation management can be more effective where the temporal high resolution remote sensing optical data as well as high resolution surface elevation data with the predicted flood risk zones can be accessed. Pre and post event temporal dataset are to be incorporated in the platform for recovery and reconstruction management. Thus, this platform can effectively minimize the adverse impact of coastal cyclonic disaster by the participation of community, stake holders and the planners.Key-words: community-based capacity, Integrated Disaster Risk Management, storm surge water flooding, web-enabled platform, participation of community. 
Modeling Heliospheric Flux-Rope Distortions
Authors: Nieves-Chinchilla Teresa , Hidalgo Miguel A. , Cremades Hebe , Weiss Andreas J.
Published: February 2023

The three-dimensional characterization of magnetic flux-ropes observed in the heliosphere has been a challenging task for decades. This is mainly due to the limitation to infer the 3D global topology and the physical properties from the 1D time serie from any spacecraft. To advance our understanding of magnetic flux-ropes whose configuration departs from the typical stiff geometries, here we present the analytical solution for a 3D flux-rope model with an arbitrary cross-section and a toroidal global shape. This constitutes the next level of complexity following the elliptic-cylindrical (EC) geometry. The mathematical framework was established by Nieves-Chinchilla et al., with the EC flux-rope model that describes the magnetic topology with elliptical cross-section as a first approach to changes in the cross-section. The cross-section is described by a general function. The model is completely described by a non-orthogonal geometry and the Maxwell equations can be consistently solved to obtain the magnetic field and relevant physical quantities. As a proof of concept, this model is generalized in terms of the radial dependence of current density components. Last part of this presentation is dedicated to study a specific event to estimate the distortion and the implications for space weather.
Probabilistic hazard assessment of pyroclastic avalanches at Mt. Etna volcano through numerical modeling
Authors: de’ Michieli Vitturi Mattia , Zuccarello Francesco , Esposti Ongaro Tomaso
Published: February 2023

One of the most hazardous phenomena which characterizes the summit activity at Mt. Etna (Italy) is represented by pyroclastic avalanches, gravity-driven flows of pyroclastic material at high particle concentration, characterized by modest volumes (usually lower than a few millions of cubic metres) and small thickness-to-length ratio. The frequency of pyroclastic avalanches at Mt. Etna has increased during the recent 2020-2022 volcanic activity, where a series of intense paroxysmal eruptions took place at the South East Crater (SEC). The accumulation of proximal deposits generated by the explosive activity led to the growth of SEC, which posed favorable conditions in triggering partial collapses of unstable flanks of the crater. Pyroclastic avalanches propagated mainly eastward and southward of the SEC, up to distances of about 2 km from the source.Numerical modeling of pyroclastic avalanche propagation and emplacement constitutes a powerful tool for hazard assessment, despite several difficulties in simulating the rheology of the polydisperse granular mixture. In this work, pyroclastic avalanches are simulated using the open-source code IMEX-SfloW2D. Depth-averaged equations are implemented in the code to model the granular flow as an incompressible, single-phase granular fluid, described by the Voellmy–Salm rheology. Comparison of numerical results with the well-documented pyroclastic avalanches occurred on 11 February 2014 and during the 10 February 2022 paroxysmal eruption (one of the most intense of the 2020-2022 series) allowed us to investigate the variability of the avalanche dynamics with its volume, the influence of the three-dimensional volcano morphology, and to statistically calibrate the unknown rheological parameters (i.e., the dry-friction coefficient µ and viscous-turbulent friction coefficient ξ). Finally, we provide a preliminary quantification of new potential collapse scenarios, to assess pyroclastic avalanche probabilistic hazard on the summit area, one of the most preferential tourists destination at Mt. Etna.