bluuebunny/crossref_metadata_2025 huggingface dataset:
Saturn's field-aligned current systems as observed by the Cassini mission
Authors: Hunt Gregory
Published: March 2022

A long-standing question within Saturn’s magnetosphere is the source of the ubiquitous oscillations, known as planetary period oscillations (PPOs). From radio and magnetometer data it is known there are two such oscillation systems, one in the northern hemisphere and the other in the southern. In this talk, we will review analyses of azimuthal magnetic field data from the Cassini mission right up to its end in 2017 which show the presence of field-aligned currents. Using these data, several field-aligned current systems are shown to be present in Saturn’s auroral regions and their relationship with the PPOs was revealed. The implications of these results on Saturn’s periodicities, aurora, and coupling between the ionosphere and magnetosphere will be discussed.  
Trait-based modeling of microbial carbon turnover in the rhizosphere
Authors: Sircan Ahmet , Giraud Mona , Lobet Guillaume , Schnepf Andrea , Streck Thilo , Pagel Holger
Published: March 2022

Exudation of organic carbon triggers complex spatial and temporal patterns of biophysical and biochemical processes in the root-influenced soil (rhizosphere). We use process-based modeling as a tool to gain insights into microbial interactions and carbon cycling in the rhizosphere. Here, we present a trait-based rhizosphere model that accounts for two different functional microbial groups (copiotrophs, oligotrophs) that differ according to life-history strategies, microbial physiology (e.g., dormancy) and carbon turnover (small and large polymers). The model is calibrated and validated against experimental data from the literature. We apply a parameter search algorithm that identifies plausible parameter spaces by conditioning model outputs to parameter and process constraints that reflect current ecological knowledge. We show the general concept of the model, first simulations after model conditioning, and a concept for coupling the rhizosphere model with the structural-functional plant model CPlantBox to cover the whole-plant scale.
Local determination of constituent's decay coefficients for river water quality modelling considering the catchment scale
Authors: Scarati Martins José Rodolfo , Amorim Lais , Nogueira Fabio , Magalhães Ariel , Duarte Barbara
Published: March 2022

Modelling water quality of polluted heavy loaded water courses as those crossing highly urbanized catchment areas are a complex task that involves several processes based on coefficients like unit loads, decay rates and self-depuration effects among others. The fate of pollutants as organic matter and nutrients are usually done through transport equations added by sourcing and sinking terms that implies the use of decay factors. The so-called k’s coefficients are present in the literature and were derived from typical water samples that don’t represent the local conditions founded in the urban rivers, usually affected by the catchment scale. This article presents an approach method used for local determination of the k’s coefficient for Biological Oxygen Demand (BOD-k1), Atmospheric Reaeration (AR-k2) and Sediment Oxygen Demand (SOD-k4) and compares results to typical adopted values bye modelists. The approach is based on local waters and sediment laboratory tests adjusted to consider specific driving forces as water temperature, constituent concentration and flow turbulence. Considering the catchment area (286 km²) and the river reach (25 km long) 4 sampling stations were defined to collect depth integrated water samples and the bed material. The k1 coefficient is the most sensible one due to the influence of the biological components and the relation between labile and refractory fractions, that varies along the reach with the contribution from the sub catchments’ land use and sanitary infrastructure. Considering Fujimoto’s and Thomas’ equations, different values of local dependent k1 were found. For k2, the concept of river shear stress velocity was applied to correlate the oxygen mass transferred to the water in the JAR test run for the observed range of velocity gradients in the natural flow. Results lead to a more realistic air entrainment rate due to hydraulic, superficial tension and presence of oils and greases. The SOD-k4 were determined after bottom sediment samples collected in the same defined stations for 3 different concentrations in clean water. The continuous oxygen demand for each sample was taken hourly in the first day and daily in the next 5, and then converted to the Toro’s active sediment layer demand considering local porosity and specific weight. Results showed considerably lower than the typical values referenced in the literature for all k’s, denoting the influence of the above-mentioned characteristics and the level of uncertainties that could affect modelling results when non-local parameters are employed.
Tectonic and climatic controls on the Late Jurassic-Early Cretaceous stratigraphic architecture of the Xuanhua basin, North China
Authors: Lin Chengfa , Liu Shaofeng , Steel Ronald
Published: March 2022

Decoding tectonic and climatic signatures from continental successions has become important in basin analysis. However, tectonic and climatic signatures can still be difficult to discriminate from each other. The late Mesozoic Xuanhua basin in the western Yanshan fold‑and‑thrust belt represents a representative intramontane basin and allows detailed stratigraphic, sedimentological, and provenance analyses. The work entailed an analysis of alluvial fan, fluvial, lake‑delta, and lacustrine systems in the Tuchengzi Fm. Lateral correlation of sedimentary columns reveals two large‑scale upward‑coarsening cyclothems each 80-240m thick, with prominent vertical changes from lacustrine through deltaic and fluvial to alluvial fan deposits. Two intervals of thrust‑related growth strata identified in the Tuchengzi Fm suggest that the cyclothems were controlled by tectonic uplift and accommodation change related to the Likouquan and the Mapu thrusting. In the lower upward‑coarsening cyclothem, stacking of small‑scale (3-16 m thick) upward‑fining cyclothems was revealed and argued to have been generated by alternating wet‑dry cycles. The wet half‑cycle started with discharge and deposition of flood‑generated mass‑flows into the lake and ended with accumulation of lacustrine mudstones as lake level rose. The lake deposits include the maximum flooding during the wet half‑cycle. The dry half‑cycle was characterized by continued lacustrine deposits, but with increased evidence of subaerial exposure indicated by rooting, paleosols and mudcracks resulting from falling of the lake level under dry conditions.
Effects of weed management on soil biophysical properties and vine physiology in an English vineyard 
Authors: Paradelo Perez Marcos , Büchi Lucie , O'Brien Flora
Published: March 2022

Climate change threatens traditional wine regions with rising temperatures and irregular rainfall patterns. Meanwhile, this is an opportunity for cooler regions to grow quality wines. In Great Britain, the land dedicated to vineyards has quadrupled since 2000 to 3,800 hectares at present. The establishment and management of these new vineyards affect soil processes that underpin ecosystem services and agriculture sustainability. The lack of long-term soil management data in the new wine regions requires the development of experiments and models that inform growers of the best practices regarding their pedoclimatic constraints. One important vineyard operation is the control of weeds under vine rows. The progressive reduction in herbicides has given way to mechanical alternatives that may lead to further soil disruption.

In this study, we investigated the effect of different weeding operations on soil biophysical properties and vine physiology in the newly developing wine region in the South East of England. A trial was established in 2018 at the NIAB EMR research vineyard (Kent, England) as part of the Horizon2020 project “Integrated Weed Management: Practical Implementation and Solutions for Europe” (IWMPRAISE) consisting of four weed management systems: 1. blade mechanical weeder, 2. serrated disc mechanical weeder, 3. herbicide application, and 4. mowing. In 2021, we collected soil samples before (April) and after (September) the application of the weeding treatments.  The soil microbial community composition has been characterized by 16S and ITS metabarcoding. Aggregate stability has been measured using SLAKES app. Yield, Nitrogen Balance Index, and vine vigour were measured to evaluate plant physiological development together with grape quality parameters.    

We will discuss the changes in soil structure and microbial community composition under the different weed control management and how they are linked to vine physiology (vigour and foliar nutritional status), must quality attributes, and yield.
Fire risk assessment for prevention improvement in the Chornobyl exclusion zone
Authors: Myroniuk Viktor , Zibtsev Sergiy , G. Goldammer Johann , Bogomolov Vadim , Borsuk Olexandr , Soshenskii Olexandr , Gumeniuk Vasyl , Zibtseva Erin
Published: March 2022

Large landscape fires in 2015 and 2020 in the Chornobyl Exclusion Zone (CEZ), that burnt in total more than 82 thousand ha of highly radioactive forest lands all over the territory, including Red Forest, located near the Unit 4 Confinement, posed a significant threat for health of fire fighters who participated in the suppression and other personnel of the Zone. Burning of forest fuel contaminated with six radionuclides generated smoke that migrated far beyond borders of the Exclusion Zone with prevailing winds towards populated areas. Future uncertainties caused by climate change require risk assessment for development of fire resilient landscape and risk-based integrated fire management system.            

To improve fire prevention in CEZ we have developed a web-based framework for assessing the potential risk of a wildfire that integrates weather data, ignition likelihood, models burn probability, contamination by radionuclides, and available firefighting resources. We combined available field sampling and forest inventory data to parametrize our fuel models. Landsat time series were used for mapping the seasonal pattern of fuels distribution, which conforms to landscape flammability. Canopy fuels were predicted using machine learning models and remote sensing data. We calibrated surface and canopy fuel metrics so that the perimeters of the largest wildfires matched those simulated using the FARSITE fire modelling system based on hourly weather data (i.e., wind speed, wind direction, precipitation etc.).

For modelling of the current risk of fires according to fire weather parameters, the relations of the area and number of fires (according to the MODIS MCD64A1 product) and the modified for Ukraine PORTU fire weather index were calculated on the basis of historical meteorological data for the period from 2010 to 2020 for CEZ. Python scripts have been developed, in order to automatically download fire weather data several times per day and calculate PORTU index in 16 km grid cells.

The research in CEZ funded by European Union’s Horizon 2020 Program within the project FirEUrisk “Development a holistic, risk-wise strategy for European wildfire management” (GA 101003890).      
Cenozoic tectonic plate interaction registered in a South Atlantic passive margin basin (southern sector, Pelotas Basin)
Authors: Colling Cassel Marlise , Girelli Tiago Jonatan , Medina Ketzer João Marcelo , Chemale Jr. Farid
Published: March 2022

The South Atlantic present-day configuration is the result of remarkable paleogeographic and paleoclimate events that occurred during the Cenozoic. These tectono-climatic events include opening and closing ocean gateways, hyperthermal events, climate changes, and the rise of the Andean Mountain Chain. This work aims to define how these events affected the evolution of the Pelotas Basin in the southern Atlantic Ocean passive margin regarding their sedimentary and geomorphic records. To reach this objective, a multiproxy and multiscale analysis based on subsurface data and regional information using seismic interpretation, backstripping, and numerical modeling was performed to identify the influence of climatic, eustatic, and tectonic triggers. Our results point that the interaction between Naszca, South America, and Antarctic tectonic plates are the root to explain the Cenozoic events registered in the South Atlantic passive margins. The Andean Mountain Chain Uplift on the west side of South America and their retroarc foreland system, the forebulge and back-bulge provinces conducted a strong tectonic control over the Pelotas Basin. On the other hand, the climatic control resulting from the Drake Passage widening and consequent development of the Antarctic Circumpolar Current changed the contour currents dynamics. In response to these tectonic-induced climatic changes, the Pelotas Basin records over the Cenozoic: a) depocenter change, b) alterations in oceanic currents described through contourite deposits, and c) formation of a huge fan-like feature (Rio Grande Fan) during an accelerated increase in the sedimentation rate and consequent gravitational collapse driven by overpressure occurred in undercompacted shales.
Tracing nitrate pollution within the Agneby subcatchment, SE Côte d'Ivoire (West Africa)
Authors: Osemwegie Isimemen , Soto David , Stumpp Christine , Coulibaly Julien Kalpy , Reichert Barbara
Published: March 2022

Coastal environments around the globe provide services and support to the population. However, they are frequently impacted by human-based activities in addition to seawater intrusion problems. These lowland groundwater resources are exposed to a significant amount and types of pollutants, the most significant of which is nitrate. Tracking and quantifying the sources of nitrate that pollute surface and groundwater systems can be challenging without the use of environmental tracers such as nitrate isotopes. This study explored how changes in regional flow paths impact the nitrogen concentrations and origin of pollution in coastal waters during high tides. Water samples were collected from surface (rivers, lagoon and Atlantic shore) and groundwater (wells and boreholes) systems along the east coast of Côte d'Ivoire during the boreal summer (October). Water samples were analysed for major ions, dissolved nitrogen concentrations, coliforms presence/amount, as well as dual nitrate isotopes (δ15N-NO3- and δ18O-NO3-). Bayesian isotope mixing models were conducted to estimate the contributions of potential main sources (wastewater, seawater, atmospheric deposition, and agrochemicals). In some areas, nitrate inputs were found likely coming from wastewater sources. Nitrate concentration in groundwater was high at several sites. Some groundwater samples (n = 7) exceeded the WHO drinking water limit of nitrate concentrations of 50 mg/l, and most groundwater samples had high levels of total coliforms (>500 cfu/100ml). However, great isotope variation found in both surface and subsurface water samples suggested a spatial differential impact and origin of nitrate pollution, which is in agreement with the modelling. These water resources are the primary source of water for 53% of the local population and an alternative domestic water source for 97%, which highlights the importance of determining the main pollution sources for sustainable development. We expected that groundwater may have been better protected from nitrate pollution than lagoon surface water during wet periods, but this might have not been the case.
CTBTO International Data Centre analysis of the Hunga Tonga–Hunga Haʻapai eruption
Authors: Mialle Pierrick , Le Bras Ronan , Bittner Paulina ,   CTBTO Colleagues
Published: March 2022

Almost 20 years ago, the first infrasound event built only from infrasound arrivals was reported in the Reviewed Event Bulletin (REB) of the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Over the last 25 years, 53 infrasound stations from the International Monitoring System (IMS) have been installed and are transmitting data to the IDC for the purpose of detecting any nuclear explosions in the atmosphere. The infrasound component of the IMS daily registers infragenic signals originating from various sources such as volcanic eruptions, earthquakes, microbaroms, meteorite entering the atmosphere or explosions. The IDC routinely and automatically processes infrasound data with the objective to detect and locate events then reviewed by interactive analysis.

As the IDC advances its methods and continuously improves its automatic system for the infrasound technology, several events received global interest from the scientific community and the public. On 15 February 2013 the Chelyabinsk meteor entered the atmosphere over Ural region (Russian Federation) and generated infrasound waves that were recorded by 20 of the 42 infrasound IMS stations operating at the time. Almost 9 years later, on 15 January 2022 the Hunga Tonga–Hunga Haʻapai eruption reached a climax around 04:15 UTC, which generated acoustic waves circumnavigating the Earth for several days. In addition to seismic and hydro-acoustic recordings, all 53 IMS infrasound stations registered signals from this eruption. This event is the largest ever recorded by the infrasound component of the IMS network.
Seabed mapping using Synthetic aperture sonar and AUV - important tools for studies of cold seep habitats
Authors: Thorsnes Terje , Chand Shyam
Published: March 2022

Cold seeps are commonly associated with water column and seabed features. Active seeps form acoustic flares in the water column and can be detected using data from single or multibeam beam echosounders. They may be associated with pockmarks, but the majority of pockmarks on the Norwegian continental shelf have proven to be inactive. Cold seeps are commonly associated with carbonate crust fields exposed at the seabed. 
Studies using multibeam echosounder water column data in the Håkjerringdjupet region, underlain by the petroleum province Harstad Basin, have revealed more than 200 active gas flares related to cold seeps. We have studied the seabed around some of these, using the HUGIN HUS AUV equipped with HiSAS 1030 Synthetic Aperture Sonar (SAS) from Kongsberg. The SAS gave a 2 x 150 m wide swath. The primary product is the sonar imagery with a pixel resolution up to c. 3 x 3 cm. For selected areas, bathymetric grids with 20x20 cm grids were produced, giving unrivalled resolution at these water depths. The carbonate crust fields have normally a characteristic appearance, with a low reflectivity and a rugged morphology compared to the surrounding sediments. 
The interpretation of the acoustic data was verified by visual inspection using the TFish photo system on the AUV, and at a later stage by ROV video footage and physical sampling. The integration of hullborne echosounder data with AUV-mounted acoustic and visual tools provides a very powerful approach for studies of cold seep habitats and related seabed features.
An important conclusion from the study is that many pockmarks are not associated with active gas seeps today, and that many of the presently active gas seeps are associated with carbonate crust fields which are readily identifiable from synthetic aperture sonar data.
The ubiquity of shallow circulations in the trades
Authors: George Geet , Stevens Bjorn , Bony Sandrine , Vogel Raphaela , Naumann Ann Kristin
Published: March 2022

We find an abundance of low-level, mesoscale circulations in the atmosphere below the trade-wind inversion layer based on observations of the mesoscale atmospheric circulation taken during the EUREC4A campaign. Over time-means of 3-6 hours, the mean sub-cloud divergence anomaly correlates negatively with the mean divergence anomaly in the cloud layer. Here, the term anomaly means the deviation from the EUREC4A-wide month-long mean of divergence at the corresponding altitude. Additionally, sub-cloud divergence anomaly correlates negatively with specific humidity anomaly in the sub-cloud and cloud layers, indicating moist, convergent regimes and dry, divergent regimes. We hypothesise that the presence of shallow circulations below the inversion layer explains these associations. Our proposed mechanism of shallow circulations is that regions of ascending air are balanced by neighbouring cells of subsidence, thus creating and maintaining moist and dry regions, which reinforce the shallow circulations. We use mixed-layer theory to estimate the time-scales at which the sub-cloud layer moisture would respond to such divergence patterns. The observed relationships are also evident in reanalysis data, which further reinforce that these are indeed mesoscale features and not large-scale signals captured by the observations.
Monitoring SAR-altimeter missions at non-dedicated tide gauge stations in the German Bight
Authors: Esselborn Saskia , Schöne Tilo
Published: March 2022

Sea level variations from satellite altimetry need to be consistently calibrated and monitored when used for climate studies. Here, we focus on the estimation of biases and the monitoring of precision and drifts of three SAR-altimeter missions (Sentinel-3A, Sentinel-3B and Sentinel-6MF) at eleven tide gauge stations in the German Bight (Southeastern North Sea). The corresponding operational GNSS-controlled tide gauge stations are partly located in open water, partly at the coast close to mudflats and deliver data every minute in the period 2016 to 2021. Instantaneous sea level (total water envelope) from altimetry is extracted at virtual stations in close vicinity to the gauges (2 to 24 km) and for different retrackers. The processing is optimized for the region and empirically adjusted for the comparison with the nearby tide gauges readings. The precision of the altimeters is depending on location and mission and is shown to be better than 3 cm. The relative drifts between tide gauges and altimetry are discussed.
Measuring of microplastics settling velocities and implications for residence times in thermally stratified lakes
Authors: Elagami Hassan , Ahmadi Pouyan , Fleckenstein Jan H. , Frei Sven , Obst Martin , Agarwal Seema , Gilfedder Benjamin S.
Published: March 2022

Microplastic (MP) residence times are currently poorly constrained in lakes, especially at a quantitative level. In this work settling experiments with pristine and biofilm-colonized MPs were combined with model calculations to evaluate settling velocities, particle distributions and residence times in the epi- meta and hypolimnion of a hypothetical stratified lake broadly based on Upper Lake Constance. Settling velocities of various biodegradable and non-biodegradable polymers of various shapes, sizes and biofilm colonization were measured in a settling column. The settling velocities ranged between ~ 0.30 and ~50 mm s-1. Particle sizes and polymer densities were identified as primary controls on settling rates. MPs that had been exposed to a lake environment for up to 30 weeks were colonized by a range of biofilms and associated extracellular polymeric substances; surprisingly, however, the settling velocity did not vary significantly between pristine and colonized MP particles. Simulated MP residence times in the model lake varied over a wide range of time scales (10-1 - 105 days) and depended mainly on the size of the particles and depth of the lake layer. Long residence times on the order of 105 days (for 1 µm MPs) imply that for small MP particles there is a high probability that they will be taken up at some stage by lake organisms. It also suggests that insignificant amounts of small MPs will be found in the lake sediment unless some process increases their settling velocity as their residence time is considerably longer than the theoretical retention time of Lake Constance (~4.5 years).
The importance of integrating Digital Twins and Earth Observation to support resilient society applications in Cyprus
Authors: Christofi Demetris , Danezis Chris , Themistocleous Kyriacos , Zacharatos Haris , Kyriakides Nicholas , Hadjimitsis Diofantos
Published: March 2022

This abstract explores the importance of integrating digital twins and earth observation for supporting natural disasters management in Cyprus. Indeed, this study shows how a digital twin will be developed based on existing sources of data like satellite imagery, maps, in situ data and other auxiliary data such as meteorological, hydrological data etc. This digital twin will be used to predict future conditions of a certain area of interest in Pafos District in Cyprus. The main aim is to update the proposed digital twin using satellite images such as Copernicus data for efficient decision making from the key stakeholders such as government and public authorities.

Several natural disasters have been identified in the national risk assessment of Cyprus as the main priorities such as floods, earthquakes, fires, landslides etc. In the proposed digital twin these four hazards will be considered. However, this abstract shows the prelimary results retrieved by examining the impact of floods in an area of interest in Pafos District area in Cyprus by integrating several data and techniques such as earth observation and hydrological modeling.
Imaging the anisotropic structure of the Reykjanes Peninsula across the 2021 Fagradalsfjall dyke intrusion through local shear-wave splitting analysis
Authors: Parsons Amber , Bacon Conor , Greenfield Tim , Winder Tom , Ágústsdóttir Thorbjörg , Brandsdóttir Bryndís , Fischer Tomas , Doubravová Jana , Rawlinson Nicholas , White Robert , Gudnason Egill Árni , Hersir Gylfi Páll , Hrubcova Pavla
Published: March 2022

Since late 2019, the Reykjanes Peninsula in Iceland has experienced elevated seismic activity, which culminated in a dyke intrusion beneath Fagradalsfjall on 24th February 2021, and an eruption on 19th March. Seismic anisotropy – the directional dependence of seismic wave speed – can be used to study structural properties of the crust, which may be controlled by the state of stress through preferential closure of micro-cracks. This provides an opportunity to investigate changes in crustal stress regime caused by a dyke intrusion, with potential applications in eruption monitoring and forecasting.

 

A dense seismic network spanning Fagradalsfjall recorded more than 130,000 earthquakes between June 2020 and August 2021; detected and located using QuakeMigrate1. From this dataset, we calculate the seismic anisotropy of the upper crust through shear-wave splitting analysis. Exceptional ray-path coverage allows for imaging at high spatial and temporal resolution. We present these results in relation to the regional stress regime and tectonic structure, and search for changes in anisotropy before, during, and after the dyke intrusion and eruption.

 

1: Winder, T., Bacon, C., Smith, J., Hudson, T., Greenfield, T. and White, R., 2020. QuakeMigrate: a Modular, Open-Source Python Package for Automatic Earthquake Detection and Location. https://doi.org/10.1002/essoar.10505850.1
The primary and secondary populations of interstellar neutral gas as seen now by IBEX and in the future by IMAP
Authors: Bzowski Maciej
Published: March 2022

As the Sun moves through its local galactic neighborhood, it disturbs the ionized component of interstellar matter, forming a complex bow-wave structure of a slowed and heated, magnetized plasma, flowing past the heliosphere. This region is called the outer heliosheath. The neutral component of interstellar matter is in equilibrium with the ionized component far ahead of the heliosphere, but within the outer heliosheath it decouples kinematically from the perturbed plasma. A complex interaction begins, mostly by charge exchange, between the ions and the neutral atoms, and as a result, a new population of neutral atoms is created, with kinematic parameters similar to that of the surrounding plasma. In addition, elastic collisions operate, additionally modifying both the original primary and the secondary population of neutral. Both the primary and the secondary populations penetrate inside the heliosphere and can be directly sampled at 1 au. We will review results of observations of these populations obtained from IBEX-Lo and results of modeling of the secondary populations of interstellar hydrogen, helium, and oxygen in the outer heliosheath. We will illustrate how these populations can be better observed owing to enhanced capabilities of the planned IMAP-Lo instrument and demonstrate how they can be leveraged to resolve the primary and secondary populations, and investigate the properties of local interstellar matter in the immediate neighborhood of the Sun.
Benchmarking Downscaled Precipitation to Optimize Stakeholder Resilience to Extremesusing the CORDEX-Australasia Ensemble
Authors: Isphording Rachael , Alexander Lisa , Bador Margot , Amoils Joshua-Brent , Green Donna
Published: March 2022

Regional governments and stakeholders increasingly request downscaled climate model simulations to better inform growing climate risks and vulnerabilities. Presently, there is no standardized framework or metrics identified to evaluate downscaled rainfall data. Previous studies typically evaluate the ensemble mean and do not holistically incorporate precipitation characteristics relevant to stakeholder needs, including extremes. I introduce a standardized benchmarking framework to evaluate downscaled rainfall across spatiotemporal scales relevant to various stakeholder applications. Benchmarking seeks to understand how well a model should perform by defining performance expectations a priori and includes thorough evaluation of model set-up (including e.g. the convection scheme and other model parameterizations). A hierarchy of model performance expectations is presented to guide users in selecting a subset of "fit for purpose" simulations to optimise rainfall projections across spatiotemporal scales and societal needs.
Characterization of an Aquifer Thermal Energy Storage system with an Active Distributive Temperature Sensing Experiment
Authors: Godinaud Jérémy , Klepikova Maria , Larroque François , Guilhéneuf Nicolas , Dupuy Alain , Pryet Alexandre , Bour Olivier
Published: March 2022

Aquifer Thermal Energy Storage systems (ATES) are reversible open loop geothermal systems involving a minimum of two reversible boreholes. It gains more and more popularity with a great potential to reduce greenhouse gas emission of the building sector.

During operation, ATES storage efficiency and energy recovery rate depend on the cold and warm thermal plumes extension. The thermal plumes shaped are particularly impacted by the aquifer vertical and horizontal heterogeneity especially regarding the flux and thermal properties distribution. In addition, ATES performance also depends of the sustainability of the wells and the major issues of their aging. Among the major causes, biofouling, chemical and physical clogging are well documented for open loop system.

However, field methods existing to quantify aquifer properties are not well suited to estimate both thermal and hydrodynamic aquifer heterogeneity with a high spatial resolution. Recent developments in Fiber-Optic Distributed Temperature Sensing (FO-DTS) have solved this issue. In particularly, active -DTS experiments (ADTS) were shown to be a promising avenue for imaging the spatial distribution of subsurface heterogeneities. It consists on monitoring the thermal response along the FO cable induced by a heat source placed in the borehole which allow to estimate thermal and hydrodynamic properties distributed along boreholes.

In that context, we performed a series of ADTS experiments on a ATES site. The field experiments were run under cross-borehole configuration and replicate in two different piezometers to check the reciprocity of the results. Our work demonstrates the potential of ADTS to estimate both thermal conductivity and groundwater flux along the two boreholes. At the same time, it was shown to be a good tool to detect clogging locations along the boreholes. The proposed experimental design is simple and the tests can be run without opening boreholes and stop the pump. First, this method enables the characterization of thermal and hydrodynamic heterogeneities to develop more advanced numerical models. Secondly, it can be used as strategy surveillance to monitor clogging evolution into geothermal boreholes and to plan maintenance works before major deterioration.
Pressure Balance at the Heliosphere Boundary and in the Local Interstellar Cloud
Authors: Möbius Eberhard , Linsky Jeffey
Published: March 2022

The pressures exerted by the solar wind from the inside and the interstellar medium from the outside control the size and shape of the heliosphere. Magnetic fields and cosmic rays play important roles to varying extents on both sides. We will assess the pressure balance by assembling the relevant component pressures in the (inner) heliosheath inside the heliopause, in the Very Local Interstellar Medium (VLISM, interstellar medium affected by the presence of the heliosphere or outer heliosheath), and in the Local Interstellar Cloud (LIC) unaffected by the heliosphere. We take the cosmic ray pressure from Voyager observations, which don’t show substantial gradients beyond the heliopause. The remaining pressure on the heliopause from inside is due to thermal and suprathermal ions in the subsonic solar wind, obtained from IBEX and INCA ENA observations and Voyager in situ measurements at the higher energies.

Besides cosmic rays, the pressure in the undisturbed LIC is composed of magnetic field pressure taken from IBEX Ribbon observations and related modeling. Thermal and turbulent pressures are based on H and He neutral and ion densities from pickup ion and interstellar gas flow observations, combined with the temperature and turbulent speed from absorption-line observations. The total LIC pressure in its rest frame is almost 40% lower than the pressure inside the heliopause, whereas adding the full ram pressure based on the LIC velocity relative to the Sun exceeds that pressure substantially. We estimate the likely effective pressure on the heliopause by combining the compressed interstellar magnetic field, as measured by Voyager, and the compressed and heated interstellar plasma, resorting to results from global heliospheric modeling. An interesting result of these pressure comparisons is that the effective ram pressure on the heliopause is somewhat larger than the combined magnetic field, thermal, and turbulent pressure in the LIC, which points to the importance of the LIC ram pressure for the shape of the heliosphere. We also compare the LIC pressure with the gravitational pressure on the galactic disk at the location of the Sun.
Seawater isotopic measurements (δ18O and δD) reveal significant freshwater influxes into the Arctic seas
Authors: Kopec Ben , Klein Eric , Pedron Shawn , Bailey Hannah , Causey Douglas , Hubbard Alun , Marttila Hannu , Noor Kashif , Welker Jeffrey
Published: March 2022

As the Arctic warms, one of the fundamental changes has been the freshening of Arctic ocean waters, impacting ocean circulation and marine ecosystems, among many other critical changes. This increase in freshwater is largely the result of increased precipitation and runoff as part of an amplified Arctic water cycle and increased influx of glacial meltwater from around the Arctic, particularly from the Greenland Ice Sheet. Tracing the sources and extent of this freshwater is critical to understanding future changes to the Arctic seas. One way of delineating these water masses is through measuring its isotopic composition (δ18O and δD), where the freshwater varies significantly from older and other ocean water sources.

In order to identify these freshwater influxes, we conducted in-situ measurements aboard the USCGC Healy that transited the Chukchi and Beaufort Seas, the Northwest Passage, and performed numerous transects across Baffin Bay and the Labrador Sea, including detailed examinations of several key fjords and coastal regions of Greenland, during autumn of 2021. Over the length of this 45 day expedition, we continuously measured the isotopic composition (δ18O and δD) of surface seawater allowing us to fingerprint these sources of freshwater and assess the spatial extent of their influence. We also collected discrete samples from over 100 CTD casts, primarily in Baffin Bay, to identify how freshwater is distributed in the ocean water column. Through these measurements, we identified numerous freshwater influxes, including anomalously high proportions of freshwater in sections of the Beaufort Sea north of Alaska and in Uummannaq Fjord along the west Greenland coast. These isotopic measurements also allow for the disentangling of different freshwater sources (i.e., precipitation or glacial meltwater). Additionally, we find that the freshwater pulses along the west coast of Greenland corresponded with relatively high levels of chlorophyll and fluorescence, suggesting a possible link between this increase in biologic productivity and an increase in the proportion of freshwater.
Geostationary or not: can we consider Meteosat-8 viewing geometries as stationary?
Authors: Tournadre Benoît , Chen Xuemei , Gschwind Benoît , Blanc Philippe
Published: March 2022

The imagery from geostationary meteorological satellites (GEO) is broadly used to produce various datasets describing the Earth's surface and atmosphere, or else energy fluxes. Some GEOs are not on a strictly geostationary orbit, with an inclination relatively to the equatorial plane that can reach several degrees. A striking example is Meteosat-8: due to operation constraints, its orbit is currently oscillating on a daily basis between latitudes circa 7° N and 7° S. A consequence is that the actual viewing geometry differs from the simple calculation based on the stationary nominal subsatellite position. In the case of Meteosat-8, the viewing zenith angles can differ up to ±7°.

We study how these differences of viewing angles can influence top-of-atmosphere (TOA) reflectance of Earth scenes. To achieve this, we simulate both clear-sky (i.e. cloudless) and overcast TOA reflectances corresponding to nominal and non-stationary viewing geometries of Meteosat-8 for the 0.6 µm channel during the period 2017-2018. Simulations are performed using the 1-D radiative transfer model DISORT within the libRadtran software package. They consider notably the anisotropy of surface reflectance which is modeled by the RossTick-LiSparse model of bidirectional reflectance distribution function and associated parameters of the product MCD43C1v6 derived from the imagery of the Moderate Resolution Imaging Spectroradiometer (MODIS). Overcast TOA reflectances are modeled with a plane-parallel thick liquid cloud.

In this presentation, we will describe how errors on TOA reflectances due to erroneous viewing geometry are distributed on the Meteosat-8 field of view and for different solar geometries. Both for clear-sky and overcast conditions, typical absolute errors range between 0.01 and 0.05, but can reach much higher values for specific geometries, notably close to the forward scattering direction.
How important is water column dissolved oxygen (O2) for lake methane emissions?
Authors: Pajala Gustav , Sawakuchi Henrique , Gålfalk Magnus , Schenk Jonathan , Rudberg David , Sieczko Anna , Karlsson Jan , Bastviken David
Published: March 2022

Lakes are major global sources of atmospheric methane (CH4), representing an important greenhouse gas. Dissolved molecular Oxygen (DO) in lakes hinders production of CH4 while promoting CH4 oxidation. Consequently, it has been suggested as an important regulator of CH4 emissions from lakes. Presence or absence of DO at the sediment-water interface could therefore influence the extent of CH4 production in top sediment layers, and the amount of CH4 that is stored in the anoxic layer of the water column and potentially emitted during water column mixing events. However, the quantitative importance of DO on CH4 fluxes remains unknown. We studied CH4 fluxes from two lake basins in northern boreal Sweden of which DO was experimentally added to the deep waters in one of the basins (experimental basin) while the other basin was left in a natural state (reference basin). We used spatial and temporally distributed flux chambers to measure CH4 fluxes while the lake basins were stratified (from June to October) and found that there was no significant difference in CH4 fluxes between the two lake basins attributable to the water column experiment. Moreover, we found that the oxygenation of the hypolimnion resulted in a large decrease in CH4 concentration in the experimental basin, in contrast to the reference basin. However, our monthly lake profile measurements indicated that only a small amount of this CH4 may have been emitted during the open-water season. First, the two lake basins were subject to incomplete spring and fall mixing events. Second, our CH4 emission and oxidation model, based on bathymetry, CH4 concentrations, depth distributed 13C/12C measurements, and gas transfer velocities, indicated that 0 – 24 % of the stored CH4 may be emitted on a yearly basis. This shows that the overall impact on CH4 emissions from boreal forest lakes, due to CH4 storage and DO, may be smaller than previously believed. However, Fluxes during the mixing events still represent a large uncertainty for the total yearly lake CH4 emissions.
Machine Learning models for Moment Magnetometry applied to High-Resolution Magnetic Maps
Authors: Volk Michael , Trubko Raisa , Fu Roger , Meade Brendan
Published: March 2022

Paleomagnetic measurements of natural remanent magnetization were – until recently -- performed on large, millimeter to centimeter-sized rock samples using classical rock magnetometers. Developments of magnetic imaging (i.e., quantum diamond microscope (QDM) and scanning SQUID microscope) allow for the measurement of individual, weakly magnetic (10-16 Am2) particle clusters within a sample. However, this increased spatial resolution adds to the complexity of the magnetic signal and requires novel approaches in analyzing the data.

Commonly, the magnetic moment of sources within a sample are analyzed by dipole inversion, meaning fitting a dipole signal to a cropped part of a magnetic map. While this gives accurate results for sources that are well separated and dipole-like in character, recovering net magnetic moments from complex maps proved difficult. 

Machine learning (ML) has been used to study a vast number of problems and has become a part of our daily lives. Here, we present the first ML model to predict net magnetic moments from magnetic maps. Our ML models consist of three simple convolutional neural networks for source declination, inclination, moment magnitude, each of which has been trained on a large (500k) synthetic map dataset. The models are tested against several datasets, varying in size, source distribution and resolution. Our models can quickly and accurately recover the magnetic moment, even for very complex (i.e., low dipolarity) maps. The accuracy of the models is < 8˚ for inclination and declination and < 10 % for moment. Surprisingly, we find little correlation in the prediction accuracy to the dipolarity of the map. These results show that ML is a promising alternative to dipole inversions, especially for maps with low dipolarity parameters, where traditional dipole inversions can fail.
Relationship between the time series of cosmic ray data and aerosol optical properties: (Case study: southern Italy, 2016-2020)
Authors: Karimian Sarakhs Faezeh , Madonna Fabio , Rosoldi Marco , De Pasquale Salvatore
Published: March 2022

Abstract

High energy Cosmic Ray (CR) particles are capable of ionizing the Earth’s atmosphere, which leads to changes in the atmospheric physical and chemical properties. One of the most important effects of interactions between the CR particles and atmospheric molecules is the formation of aerosol and its subsequent condensation nuclei processes. These interactions are known with considerable uncertainty yet and may translate into even bigger uncertainties in future climate predictions. Laser Detection and Ranging (LIDAR) is currently the best suited technology to retrieve aerosol optical and microphysical properties is also used for the atmosphere correction of high energy cosmic ray observatory data. LIDAR measurements are available from single stations or from networks at continental scale like the European Aerosol Research LIdar NETwork (EARLINET). Sun photometer data are the most suitable complement to LIDAR measurements for the study of aerosol properties due to the extensive coverage of their measurements available through the AErosol RObotic NETwork (AERONET) network. The purpose of this study is to find the correlation between the aerosol properties and the CR data. The aerosol properties retrieved from two databases for the period of 2016-2020: I) the multi-wavelength LIDAR system Potenza EArlinet Raman Lidar (PEARL) which operates at the CNR-IMAA (Tito Scalo (Italy) and contributes to the EAELINET); and II) the AERONET sun photometer data from the stations located at Southern Italy i.e. Potenza (40.60° N, 15.72° E, 820m), Naples (40.83° N, 14.30° E, 50 m) and Lecce (40.33° N, 18.11° E, 30m). whereas, the CR data made available in Italy from the Extreme Energy Events project (http://eee.centrofermi.it/monitor). Air mass back-trajectories were used to confirm the observed aerosol types and support the correlation study. Our study showed promising results in understanding the relationship between cosmic ray and aerosol properties.

Keywords: Cosmic Ray, Aerosol, Lidar, Sun Photometer, Back-trajectory
Open Science in the publishing landscape of hydrology research
Authors: Dogulu Nilay , Popp Andrea L. , Hall Caitlyn A. , Saia Sheila M. , Schymanski Stanislaus J. , Drost Niels , van Emmerik Tim , Hut Rolf
Published: March 2022

The universe of Open Science is expanding with many scientific disciplines, organizations and policymakers committing to openness, accessibility, transparency and reproducibility. The paper “A Hydrologist’s Guide to Open Science” (Hall et al., 2022) introduces four Open Hydrology Principles and provides a practical guide to empower hydrologists across the globe as they transition to open, accessible, reusable, and reproducible research in their academic work and beyond. In this poster, we will focus on the fourth principle of Hall et al. (2022), Open Publishing, which should build on the other three principles (1. Open Research Process and Approach, 2. Open Data, 3. Open Software Development and Use). We will present current Open Science policies of major hydrology journals based on the following five criteria: a) open-access model, b) publication finance policy, c) preprint policy, d) release requirements for data, code and software, and e) peer-review procedure. This overview can serve as a guideline for researchers that are in search of journals aligning with their Open Science perspectives. Additionally, we hope to kick off a broader discussion about the hydrologic publishing landscape and how it can evolve to foster Open Science.

Reference

Hall, C.A., Saia, S.M., Popp, A.L., Dogulu, N., Schymanski, S., Drost, N., van Emmerik T. Hut, R., A Hydrologist’s Guide to Open Science. Hydrology and Earth System Sciences, doi.org/10.5194/hess-2021-392 (in print)