bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear techniques for surveillance and monitoring of antimicrobial and antimicrobial resistance in soil and the environment
Authors: Seidel Michael , Göpfert Lisa , Elsner Martin , Nijenhuis Ivonne , Adu-Gyamfi Joseph , Heng Lee , De Souza Marlos
Published: March 2020

Antimicrobials (AM) play a critical role in the treatment of human and animal (aquatic and terrestrial) diseases, which has led to their widespread application and use. Antimicrobial resistance (AMR) is the ability of microorganisms (e.g. bacteria, viruses and some parasites) to stop an antibiotic, such as an antimicrobial, antiviral or antimalarial, from working against them. Globally, about 700 000 deaths per year arise from resistant infections as a result of the fact that antimicrobial drugs have become less effective at killing resistant pathogens. Antimicrobial chemicals that are present in environmental compartments can trigger the development of AMR. These chemicals can also cause antibiotic-resistant bacteria (ARB) to further spread antibiotic resistance genes (ARG) because they may have an evolutionary advantage over non-resistant bacteria. Thus, AMR is a global threat to health, livelihoods and the achievement of the Sustainable Development Goals, both in developing and developed countries. For some time now, antimicrobial resistance (AMR) has been approached mainly from the human and animal health angles, however little is known about the impacts that AMR in the environment may have on health. A better understanding of how antimicrobial resistance moves from agricultural areas to the environment through soil and water is important if we are to develop guidance to managing it cost effectively. We examined the potential of nuclear techniques—the application of compound-specific stable isotope analysis (CSIA)—as a powerful tool to determine the source and fate of antibiotics in the environment and detect the degradation of antibiotics by transformation-induced isotopic effects. CSIA can be used to qualify and quantify in situ transformations. The latest methodological advances even allow the analysis of several elements (H, C, Cl, N) within a molecule This multi-element isotope information is used to elucidate in-situ transformation pathways and underlying reaction mechanisms.
Analyzing the 2011 eruption of Nabro volcano using satellite remote sensing and numerical modeling of lava flows
Authors: Del Negro Ciro , Ganci Gaetana , Cappello Annalisa , Bilotta Giuseppe , Corradino Claudia
Published: March 2020

The 2011 eruption of Nabro volcano, situated at the southeast end of the Danakil Alps in Eritrea, has been the first historical on record and one of the largest eruptions of the last decade. Due to the remote location of the Nabro volcano and the lack of data from ground monitoring networks at the time of the eruption, satellite remote sensing gives the first global view of the event, providing insights on its evolution over time. Here we used numerical modeling and high spatial resolution satellite data (i.e. EO-ALI, ASTER, PlanetScope) to track the path and velocity of lava flows and to reconstruct the pre- and post-eruptive topographies in order to quantify the total bulk volume emitted. High temporal resolution images (i.e. SEVIRI and MODIS) were exploited to estimate the time-averaged discharge rate (TADR) and assess the dense rock equivalent (DRE) lava volumes constrained by the topographic approach. Finally, satellite-derived parameters were used as input and validation tags for the numerical modelling of lava flow scenarios, offering further insights into the eruption and emplacement dynamics. We found that the total volume of deposits, calculated from differences of digital elevation models (DEMs), is about 580 × 106 m3, of which about 336 × 106 m3 is the volume of the main lava flow that advanced eastward beyond the caldera. Multi-spectral satellite observations indicate that the main lava flow had reached its maximum extent (∼16 km) within about 4 days of the eruption onset on midnight 12 June. Lava flow simulations driven by satellite-derived parameters allow building an understanding of the advance rate and maximum extent of the main lava flow showing that it is likely to have reached 10.5 km in one day with a maximum speed of ~0.44 km/h.
Arctic Sea Ice in the Community Earth System Model version 2 (CESM2) over the 20th and 21st Centuries
Authors: DeRepentigny Patricia , Jahn Alexandra , Holland Marika , Smith Abigail
Published: March 2020

Over the past decades, Arctic sea ice has declined in thickness and extent and is shifting toward a seasonal ice regime. These rapid changes have widespread implications for ecological and human activities as well as the global climate, and accurate predictions could benefit a wide range of stakeholders, from local residents to governmental policy makers. However, many aspects of the polar transient climate response remain poorly understood, particularly in regard to the response of Arctic sea ice to increasing atmospheric CO2 concentration and warming temperatures. The Coupled Model Intercomparison Project Phase 6 (CMIP6) provides a useful framework for understanding this response, and the participating climate model simulations are a powerful tool for advancing our understanding of present and future changes in the Arctic climate system.

Here we explore the current and future states of Arctic sea ice in the Community Earth System Model version 2 (CESM2), the latest generation of the CESM and NCAR’s contribution to CMIP6. We analyze changes in Arctic sea ice cover in two CESM2 configurations with differing atmospheric components: the “low-top” configuration with limited chemistry (CESM2-CAM) and the “high-top” configuration with interactive chemistry (CESM2-WACCM). We find that the two experiments show large differences in their simulation of Arctic sea ice over the historical period. The CESM2-CAM winter ice thickness distribution is skewed thin, with an insufficient amount of ice thicker than 3 m. This leads to a lower summer ice extent compared to the CESM2-WACCM and observations. In both experiments, the timing of first ice-free conditions is insensitive to the choice of future emissions scenario (known as the shared socioeconomic pathways, or SSPs, in CMIP6), an alarming result that points to the current vulnerable state of Arctic sea ice. However, if global warming stays below 1.5°C, the probability of an ice-free summer remains low, consistent with other recent studies. By the end of the 21st century, both experiments exhibit an accelerated decline in winter ice extent under the high emissions scenario (SSP5-8.5), leading to ice-free conditions for up to 8 months and an open-water period of 220 days or more depending on the region. Initial results show that the CESM2 simulates less ocean heat loss during the fall months compared to its previous version, delaying the formation of sea ice and leading to lower winter ice extent. Given that the CESM2 reaches a higher atmospheric CO2 concentration and thus warmer global and Arctic temperatures by 2100, these results suggest the presence of emerging processes associated with a state of the Arctic climate that has never been sampled before.
Measuring model improvement using surface energy budget process relationships: the impact of a new snow model
Authors: Day Jonathan , Arduini Gabriele , Magnusson Linus , Sandu Irina , Beljaars Anton , Richardson David
Published: March 2020

Energy exchange at the snow-atmosphere interface in winter governs the evolution of temperature at the surface and within the snow, preconditioning the snowpack for melt during spring. This study illustrates a set of diagnostic tools that are useful for evaluating the energy exchange at the Earth surface in a numerical weather prediction model from a process-based perspective using in-situ observations. In particular, a new way to measure model improvement using relationships between different terms in the surface energy budget (SEB) is presented. These process-oriented diagnostics provide a holistic view the realism of the balance of terms in the SEB, ensuring that improvements in headline skill scores, such as 2m temperature, are happening for the right reasons. Correctly capturing such process relationships is a necessary step to achieve reliable weather forecasts.

These diagnostic techniques are applied to assess the impact of a new multi-layer snow scheme in the ECMWF-Integrated Forecast System at two high-Arctic sites (Summit, Greenland and Sodankylä, Finland). The multi-layer scheme is expected to replace a single layer snow scheme enhancing the 2m temperature forecast accuracy and reliability across the northern hemisphere in boreal winter. 
The October 2019 earthquake swarm in the Mineral Mountains, Utah and its relation to the geothermal system
Authors: Mesimeri Maria , Pankow Kristine , Baker Ben , Hale Mark
Published: March 2020

In October 2019 an earthquake swarm initiated in the Mineral Mountains, Utah near the Roosevelt Hot Springs. The area has been characterized as swarm-genic after the recording of an energetic swarm (1044 microearthquakes, M less than 1.5) during the summer of 1981. This study primarily aims to investigate the spatio-temporal properties of the newly detected earthquake swarm and compare its occurrence to prior seismic activity. The October, 2019 earthquake swarm lasted four days and consists of forty-three shallow earthquakes that were cataloged by the University of Utah Seismograph Stations (UUSS) with magnitudes -0.7 to 1.31. All the events were recorded by a dense local broadband seismic network located around the Frontier Observatory for Research in Geothermal Energy (FORGE) in southcentral Utah, ~10 km west of the activated area. The close proximity of the seismic network along with the density of the seismicity allows us to apply techniques for improving the detection level and earthquake location. To achieve this, we use the earthquakes detected by the UUSS as templates and scan the continuous data for new events by applying a matched filter technique. To perform a detailed spatial analysis of the earthquake swarm and look for migration patterns, we create a high-resolution earthquake catalog using a double difference technique and differential times from both catalog and cross correlation data. To gain insight into the stress regime, we compute fault plane solutions from first motions for individual events and composite focal mechanisms for families of similar events. We further attempt to explore the underlying mechanism by examining the presence of repeating earthquakes comprising the earthquake swarm and their relation to aseismic slip. Such observations may shed insights into the role of fluids and the influence of the high heat flow, due to the geothermal system, on earthquake triggering and migration.

 
The distribution pattern of Rare Earth Elements (REE) in Vitis vinifera L. discriminates the substrate of growth ?
Authors: Barbera Marcella , Zuddas Pierpaolo , Saiano Filippo
Published: March 2020

Rare Earth Elements (REE) have been employed to stimulate the plant growth in national and international strategies while their role still remains controversial as the process involved in soil-plant system is not completely understood yet.  

In this study we have investigated the effect of REE amount in the substrate during the Vitis vinifera L growth analysing the REE distribution in the different part of the plants. Experiments were carried out over 1 year using two different substrates: one with a "natural" substrate (blank experiments) and another using the same substrate artificially enriched by an equimolar solution of REE (spiked experiments).

We found that both plant mass and amount of REE in leaves are both not influenced by the substrate enrichment. However, roots are by 1 order of magnitude enriched in REE for the 3 orders of magnitude enriched substrate of growth. This indicates that Vitis vinifera L. does not significantly transfer REE into the aerial parts during growth while identify roots as the plant critical parts responsible for the filtering of the environmental stress.  Plotting the REE normalized distribution for every element, the different experimental conditions can be significantly discriminated: under spiked substrate conditions, REE normalised distribution shows a ‘zig zag’ pattern in both leaves and roots. We propose that the REE normalised distribution pattern measured in the different plant parts (leaves and roots) can be used to discriminates the conditions of substrate characteristics during the vitis vinifera growth. Acting as natural tracers, the REE normalised distribution could be potentially used as tool tracing the substrate origin of the Vitis vinifera plant. 
p-norm regularization in variational data assimilation
Authors: Bernigaud Antoine , Gratton Serge , Lenti Flavia , Simon Ehouarn , Sohab Oumaima
Published: March 2020

 We introduce a new formulation of the 4DVAR objective function by using as a penalty term a p-norm with 1 < p < 2. So far, only the 2-norm, the 1-norm or a mixed of both have been considered as regularization term. This approach is motivated by the nature of the problems encountered in data assimilation, for which such a norm may be more suited to tackle the distribution of the variables. It also aims at making a compromise between the 2-norm that tends to oversmooth the solution or produce Gibbs oscillations, and the 1-norm that tends to "oversparcify" it, in addition to making the problem non-smooth.

The performance of the proposed technique are assessed for different p-values by twin experiments on a linear advection equation. The experiments are then conducted using two different true states in order to assess the performances of the p-norm regularized 4DVAR algorithm in sparse (rectangular function) and "almost" sparse cases (rectangular function with a smoother slope). In this setup, the background and the measurements noise covariance are known.

In order to minimize the 4DVAR objective function with a p-norm as a regularization term we use a gradient descent algorithm that requires the use of duality operators to work on a non-euclidean space. Indeed, Rn together with the p-norm (1 < p < 2) is a Banach space. Finally, to tune the regularization parameter appearing in the formulation of the objective function, we use the Morozov's discrepancy principle.
Methodology for rockfall activity identification and Machine Learning classification based on Point Clouds monitoring in Montserrat Massif (Spain)
Authors: Blanco Laura , Garcia-Sellé David , Pascual Nicolas , Puig Anna , Salamó Maria , Guinau Marta , Gratacós Òscar , Muñoz Josep Anton , Janeras Marc , Pedraza Oriol
Published: March 2020

In recent years, different techniques and devices (LIDAR, photogrammetry, UAVs or hyperspectral sensors….) have been used to acquire large amounts of data for the study of the earth’s surface offering high temporal, spatial and spectral resolutions. However, a problem lies on the availability of an efficient methodology to extract the desired information with geological signification from these large datasets. Minimal intervention of the experienced users and automatic or semi-automatic data processing are mandatory to avoid dilatory processes and to obtain productive results.

Our aim is to develop a new methodology for the identification and classification of changes in the surface of cliffs from consecutive point clouds. The new algorithms implemented recognize the different orientations of the point cloud and then, compare each point respect to a previous one in the normal direction isolating clusters of displaced points. Thereafter, these clusters of points are classified according to geometrical and raw data parameters in a) rockfalls, b) small movements of the rock surface and c) non-interest clusters of vegetation or noise like edge effects. The methodology is focused on creating more geometrical features which serve as criteria to identify and classify the differences between two point clouds. Actually, the number of clusters remains slightly high for manual processing. In this regard, the aim is to minimize the interaction of the user and take advantage of the large volume of data generated from high temporal resolution associated with the monitoring. The high number of events collected along years of monitoring allows the use of Machine Learning techniques to improve the classification of clusters automatically.

Montserrat Massif (Catalonia, Spain) is a singular case study of rockfall risk to apply the developed methodology due to the high presence of visitors, whose security conflicts with natural heritage preservation. For a correct design of infrastructures protection measures, a rockfall monitoring plan is under development including Terrestrial Laser Scanner from 2007.
Origins and Evolution of the Electron and Ion Populations of the Magnetopause’s Boundary Layers
Authors: Berchem Jean , Lapenta Giovanni , Richard Robert , Paterson William , Escoubet C. Philippe
Published: March 2020

Increasingly sophisticated instruments and simulations have revealed a wide variety of plasma processes and multiscale structures at the dayside magnetopause. In this presentation, we focus on the origins and evolution of the plasma populations observed in the magnetopause boundary layers. We present the results of Particle-In-Cell (PIC) simulations encompassing large volumes of the dayside magnetosphere. The implicit 3D PIC code used in the study was initialized from a global MHD state of the magnetosphere for southward interplanetary field conditions.  Three-dimensional plots of the perpendicular slippage indicates that reconnection occurs over most of the dayside magnetopause. However, the simulation reveals that the reconnection region has a much more filamentary structure than the X-line expected from the extrapolation of 2D models and that multiscale structures thread the reconnection outflow. In particular, the simulation indicates the formation of multiple layers of electrons with significant field-aligned velocities along the main magnetopause current layer. We use velocity distribution functions at different locations in the reconnection outflow to characterize the origins and evolution of the electron and ionpopulations of the magnetosheath and magnetospheric boundary layers and compare them with observations from the MMS and Cluster spacecraft.
A database of Black Sea beaches
Authors: Görmüş Tahsin , Ayat Berna , Aydoğan Burak
Published: March 2020

Beaches are not only one of the most beautiful natural entities the world coasts, they are also habitat for various species of living creatures, barrier against coastal hazards. Their conservation is crucially important, yet the efforts seem deficient. Geographic information systems are great tools towards this aim by incorporating coastal data and visually representing them. In this study, a database for all the beaches along the Black Sea coastline is created to help the efforts on marine conservation and coastal management. 1553 beaches have been digitized as polygons using satellite images between 2013 and 2016 covering the entire Black Sea coast. Geometric properties such as area, perimeter, width, central coordinates, UTM zone, shoreline length, and bound orientation are obtained through different data collection techniques. Information related to natural properties such as estuaries, coastal structures, and settlement densities have been gathered. Results indicated that Black Sea beaches are relatively narrow. Most of them are either experienced erosion or have a vulnerability to erosion. Among all 1553 beaches, only 28 beaches have an average width wider than 100 m. In the basin, the average width of the beaches is 26.04 m, the average beach area is 70384.2 m2 and the total beach shoreline length is 2116.12 km, which covers 43% of the Black Sea coastline. The mean slope values of the beaches with a maximum width of greater than 100 m are calculated using ASTER Digital Elevation Model v2. According to this analysis, the mean slope of these 164 beaches is 7.28 degrees. An additional analysis is performed by creating a different layer for the South-western part of the basin, from approximately 5 years older satellite images. This analysis showed that, even in the short-term, beaches can experience significant area loss reaching up to 50% in a relatively high wave climate such as exists in the South-western part.
Stylolites:when they became conduits for fluid pathway ?
Authors: Repetto Giuseppe , Magni Silvana , Sardini Paul , Sattari Marja Siitari , Sammaljärvi Juuso , Mazurier Arnaud
Published: March 2020

Dissolution process is a complex phenomenon controlled by several factors such as the nature of chemical dissolution, lithology, porosity, stress orientation, environmental conditions, networks of fractures. In the karst field, however, compressional tectonic structures, as like stylolites, are never been taken into consideration for fluid flow. Stylolites are formed by a pressure solution processes that dissolves the soluble particles and leads to an enrichment in insolvable, non-carbonate particles (NCP) along their surfaces. Potentially they play an important role in ﬂuid circulation during carbonate deformation.

Although they seem macroscopically planar, stylolites have an extremely variable shape from the meso- to microscale, with variable porosity and permeability. Because of this, they have a strong effect on regional fluid flow and the formation of reservoirs since they can act as barriers or conduits for flow.

In this research we investigated the distribution of voids and pores present both within and near the stylolites.This task is challenging because the pore sizes are small and therefore difficult to investigate. To determine which role the NCP and these structures have on fluid circulation, a comparison is herein presented between two different methods used to map the submicroscopic arrangement of pores and voids in and around stylolites. Because the investigated stylolites are relatively narrow, around 30-50 µm, we decided to use a classical micro Computed Tomography (µCT) technique supported by the 14C-PMMA impregnation method on two marble samples. These two comprelementary methods characterize the spatial distribution of connected voids in and around stylolites. µCT analysis provide adequate information on the 3D distribution of voids even if nanometer scale pores and small fractures are difficult to observe using µCT.

14C-PMMA method is however able to reveal connected porosities from mineral areas that consist of nanometer scale pores. Methylmethacrylate intrudes into nanometer scale pores, and autoradiography is used to visualize the porosities thanks to 14C beta emissions. Combining these two techniques, CT tomography and PMMA autoradiography we can visualize the 3D pore structures of the studied samples.

The results show that the micro CT technique supported by the PMMA autoradiography technique provides a useful tool to characterize the voids and pore structures of geomaterials.

The results allowed a more accurate description of the behavior of stylolites in fluid-rock interaction.

 

Key words: stylolites, permeability, microCT and 14C-PMMA impregnation

 
The circular ecological economy - a beneficial environment in light of the use of natural resources in the Republic of Moldova
Authors: Cojocaru Olesea , Siscan Zorina
Published: March 2020

The welfare of the Republic of Moldova much depends on the use of its natural resources. However, the pace at which the natural resources are exploited exceeds the ability of the environment to regenerate them. Land resources are the main natural wealth of the country. The conservation and increase of effective fertility of the soils becomes the basic task of the owners of agricultural lands. The methods of the conventional agriculture do not work anymore to make the sector competitive at regional and global markets. New concepts and technologies of Green and Circular economy are of more perspective. They also are more effective under the continuous unbalanced extraction of natural resources which causes environmental damage.

The case of Moldova reflects the global trends. Some international studies have shown that the global consumption of materials per capita has doubled, while the consumption of primary energy has tripled in the last hundred years. In other words, each of us consumes three times as much energy and twice as much material as our predecessors consumed in 1900. Moreover, nowadays there are 7.2 billion consumers compared to 1.6 billion in 1900.

At the same time, the requirements for quality standards in Green economy are very high and rigid as well as  “the annual financing demand to green the global economy has been estimated to be in range 1.05 USD to 2.59 USD trillion” (UNEP, 2011). That is why the Circular ecological economy is seen as more viable solution for world, regional and national economies. ”Ecological economy” generally refers to an economy in which all the choices regarding production and consumption are made taking into account the welfare of the society and the global health of the environment. ”Circular economy” implies a system of production and consumption that generates as little loss as possible.

The EU Circular economy Package and CE Stakeholder Platform are a good start for regional economy as well as that of Republic of Moldova as its Associate Member. The beneficial solution for improving the environment of the country consists in redesigning products, production and consumption processes by minimizing waste and transforming that unused part into a resource.
HAPPI-Health: The Paris Agreement avoids substantial extreme heat-related mortality
Authors: Lo Eunice , Mitchell Dann , Gasparrini Antonio , Vicedo-Cabrera Ana
Published: March 2020

Extreme heat is associated with increased risks of human mortality. In a warming climate, extreme heat events are projected to intensify and become more frequent, potentially adversely affecting human health. The Paris Agreement aims at limiting global mean temperature rise this century to well below 2°C above pre-industrial levels, but mitigation ambition as established in nations’ initial Nationally Determined Contributions still implies ~3°C warming. Quantifying the differences in extreme heat-related mortality between 1.5, 2 and 3°C warming is essential to understanding the public health impacts of climate policies and how societies may adapt to a warming climate.

In this talk, I will show a new approach to projecting extreme heat-related mortality using the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) large ensemble and health models. The large ensemble of HAPPI simulations of the 1.5, 2 and 3°C warmer worlds allows extreme heat events and their health impacts in these worlds to be examined, rather than the mean climates. Using published case studies of the United States and Europe; I will demonstrate that limiting global mean warming from 3°C to 2°C or 1.5°C above pre-industrial levels could reduce heat-related mortality associated with extreme heat events, with the 1.5°C limit being substantially more beneficial to public health than 2°C. In addition to climate change, I will discuss the roles of urbanisation, population changes and adaptation in future extreme heat exposure and heat-related mortality.
A new physically-based catchment modelling tool for reservoir re-engineering and renaturalisation
Authors: Hughes Daryl , Parkin Geoff , Birkinshaw Stephen
Published: March 2020

The hydrological regimes of European catchments have been considerably modified by anthropogenic features such as dams, weirs and water abstractions, with nearly every major river fragmented. The negative impacts of such physical modifications on freshwater ecosystems are being increasingly recognised. Currently, European dam removal initiatives are being driven by factors such as the EU Habitats Directive, and the costs associated with maintaining redundant infrastructure. Climate change and the rewilding agenda may encourage further hydrological renaturalisation initiatives. In the English Lake District, several reservoirs are being actively considered for decommissioning within this decade. To understand how such catchments would respond to lake renaturalisation, robust catchment hydrology models are needed that can represent the effects of changes in physical infrastructure on the hydrological regime. However, many models tend to neglect such human impacts.

We present a new tool that incorporates reservoirs, including impounding structures, river regulations and abstractions. The method involved development of an enhanced version of the freely-available catchment modelling software, SHETRAN. A new ‘reservoir’ module was developed which includes the effects of hydraulic structures and sluice operations on lake stage and river flow. Results for the Crummock Water catchment and reservoir show that the reservoir model generates notably fitter simulations, particularly during dry periods where reservoir operations cause a distinct deviation from the regime expected in natural lake-river systems. Further simulations demonstrate quantitatively how lake renaturalisation might affect future hydrological regimes compared with the baseline scenario. Finally, we discuss the implications of this model for decision-making in the Crummock Water catchment, and the utility of the software for other anthropologically-modified catchments.
Determination of the silver concentration with ion-selective electrode potentiometry
Authors: Chupakhina Nataliia , Novikov Oleg , Maslennikov Pavel , Chupakhina Galina
Published: March 2020

For technological control of hydrometallurgical processes, it is especially important to obtain data on element concentrations with an express method. Potentiometry on an ion-selective electrode makes it possible to determine concentrations in real time. We propose a method for calculation of silver concentrations for chloride solutions.

In chloride solutions, silver is present in several forms: the cation [Ag+] and the complexes [AgCl], [AgCl2]-, [AgCl3]2-, [AgCl4]3-. The ion-selective electrode is calibrated using an AgNO3 solution that contains exclusively Ag+ cations; therefore, it actually determines only the cation content. However, in chloride solutions the cationic form of silver is present in a minimum concentration. Complexes with chloride anions have an opposite charge and are not fixed during the analysis. The total silver concentration can be estimated by measuring the total chloride content in the sample. Using the reference data on the stability constants and information on the concentration of silver cations obtained with potentiometry on an ion-selective chlorine-silver electrode we developed a mathematical model in order to calculate the total silver concentration. Using this model, the total concentration of all the forms of silver was calculated. The data are summarized in Table 1.

Calculating the equilibrium concentration we found that in high-salinity solutions silver prevails in the form of [AgCl4]3-. All the other complexes are present in smaller quantities. This result shows that it is important to take into account the complexes formation in potentiometric measurements on ion-selective electrodes.

 
A Unique Airborne Multi-angular Dataset for Calibration and Validation of Earth Satellite Products
Authors: Gatebe Charles , Poudyal Rajesh , King Michael
Published: March 2020

The Cloud Absorption Radiometer (CAR) Science Team, and the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) recently released a unique dataset of bidirectional reflectance-distribution function (BRDF) of different surface types including clouds, snow/ice, vegetation, ocean, lakes, desert, city scape, smoke and other mixed surface types. The data were acquired during numerous field campaigns around the world, with measurements spanning 1991 to 2017. This presentation will address several uses of these data including developing new methods that define important surface and atmosphere radiative transfer functions, improve remote sensing retrievals of multiple geophysical parameters such as aerosols, clouds and surface albedo, and support satellite remote sensing activities.  CAR data are archived at GES DISC:  https://disc.gsfc.nasa.gov/datasets?keywords=car.
Application of a low-cost NDIR sensor module for measurements of in situ soil CO2 concentration
Authors: Heger Adrian , Kleinschmidt Volker , Gröngröft Alexander , Kutzbach Lars , Eschenbach Annette
Published: March 2020

We applied the low-cost non-dispersive infrared sensor module K33 (ICB, Senseair, Sweden) for measurements of soil CO2 concentration. We integrated the sensor module in a new soil probe suitable for in situ measurements of soil gas CO2 concentration. Therefore, we covered the sensor module with epoxy resin. For continuous measurements, we connected our soil CO2 probe to a microcontroller (MEGA 2560 Rev3, Arduino.cc, Italy) equipped with a data logging shield (Adalogger FeatherWing, Adafruit, USA). In a laboratory experiment, we evaluated the accuracy and precision of our soil CO2 probe at changing temperature and humidity by comparison with the often used CO2 probe GMP343 (Vaisala, Finland) as a reference. In a field experiment, we buried our soil CO2 probe to test its performance under natural environmental conditions.

The result of the laboratory experiment is that our soil CO2 probe compares well with the GMP343, even at maximum relative humidity. The accuracy (<0.1 % CO2) was below the accuracy given by the manufacturer. The field experiment demonstrated that our soil CO2 probe provides high-quality measurements of soil CO2 concentrations under in situ soil conditions. After retrieving it, it still measured with the same accuracy and precision as before.

In summary, we used the sensor module K33 for the first time to measure in situ soil CO2 concentrations by integrating it into a newly developed probe. The cost-efficient availability of our CO2 probe opens up the opportunity to carry out continuous soil CO2 measurements over long time periods with simultaneously high spatial resolution.
Long-term trends of surface reflectance derived from models, satellite and in-situ observations over polar areas
Authors: Lanconelli Christian , Cappucci Fabrizio , Mota Bernardo , Gobron Nadine , Driemel Amelie , Lupi Angelo
Published: March 2020

Nowadays, an increasingly amount of remote sensing and in-situ data are extending over decades. They contribute to increase the relevance of long-term studies aimed to deduce the mechanisms underlying the climate change dynamics. The aim of this study is to investigate the coherence between trends of different long-term climate related variables including the surface albedo (A) and land surface temperature (LST) as obtained by remote sensing platforms, models and in-situ observations. 

Directional-hemispherical and bi-hemispherical broadband surface reflectances as derived from MODIS-MCD43 (v006) and MISR, and the analogous products of the Copernicus Global Land (CGLS) and C3S services derived from SPOT-VEGETATION, PROBA-V and AVHRR (v0 and v1), have been harmonized and, together with the ECMWF ERA-5 model, assessed with respect ground data taken over polar areas, over a temporal window spanning the last 20 years.  

The benchmark was established using in-situ measurements provided from the Baseline Surface Radiation Network (BSRN) over four Arctic and four Antarctic sites. The 1-minute resolution datasets of broadband upwelling and down-welling radiation, have been reduced to directional- and bi-hemispherical reflectances, with the same time scale of satellite products (1-day, 10-days, monthly).  

A similar approach was used to investigate the fitness for purpose of Land Surface Temperature as derived by MODIS (MOD11), ECMWF ERA-5, with respect to the brightness temperature derived using BSRN measurements over the longwave band.  

The entire temporal series are decomposed into seasonal and residual components, and then the presence of monotonic significant trends are assessed using the non-parametric Kendall test. Preliminary results shown a strong correlation between negative albedo trends and positive LST trends, especially in arctic regions. 
Below-ground functional traits during nutrient-acquisition affect the availability of rare earth elements to plants
Authors: Wiche Oliver , Heilmeier Hermann , Pourret Olivier
Published: March 2020

Rare Earth Elements (elements from 57 to 71; REEs) are present in almost all soils at quantities similar to some plant nutrients such as copper and zinc and, therefore, are of increasing interest in phytomining research. In soilREEs interact with nutrient-bearing soil phases (phosphates, Fe-oxyhydroxides, soil organic matter) which ultimately lowers their mobility in soil solution and availability to plants. The availability of nutrients in the rhizosphere (especially that of phosphorous) is dependent on the activity of rootsand associated microbes, particularly their ability to acidify the surrounding soil and release chelating compounds such as carboxylates. There is a general consensus that root exudates released under P/Fe deficiency (protons and chelating compounds) can mobilize REEs in soil. However, until today information on effects of below-ground functional traits in nutrient acquisition on the mobility of REEs in the rhizosphere and uptake in soil-grown plants is very scarce.Preliminary results from greenhouse and large-scale field experiments indicate that P-inefficient species show different REE-concentrations in their leaves than P-efficient species, and that the pattern of REEs is related to the composition of root exudates.These findings highlight the role of rhizosphere processes on the availability of REEs representing important background information for the optimization of phytoextraction techniques. Moreover, we hypothesize that concentrations and fractionation pattern of REEs in plant material could potentially be used as an “easily-measurable” tool to evaluate the nutrient-acquisition strategy in plants. In ongoing experiments,this hypothesis will be rigorously tested by coupling a field sampling campaign of plant material from species with contrasting nutrient-acquisition strategies along soils with changing nutrient availability (e.g. Western Australian chronosequences) as well as controlled greenhouse experiments for mechanistic elucidation of processes involved.
Elaboration of charts based on geometry variations for the design of thermo-active piles
Authors: Smiljanovska Mila , Mroueh Hussein , Habert Julien , Josifovski Josif
Published: March 2020

Contemporary living, the extreme climate changes and the necessity of renewable energy sources challenge the engineers around the globe to discover advanced methods of enabling a more comfortable life. For this purpose, geothermal energy systems are used to satisfy the calorific needs for cooling and heating. Thermo-active geo-structures, as dual-function elements, offer structural improvement and simultaneously provide eco-friendly and long-term cost-friendly solutions. This contribution provides an overview of the design of geothermal piles based on geometry variations. Hence, thermo-mechanical analyses are performed for axially loaded piles based on the load transfer approach using t-z curves method. With an absence of precise regulations and standards, the aim of these analyses is to simplify the design of thermo-active piles by generating an envelope chart utilizing the results for piles with different lengths and diameters. However, keeping a more realistic ratio of the geometry is of a significant importance, so that the piles are applicable on real project solutions.

 
Late Quaternary Tectonics vs Sedimentation history of the offshore Termini in a seismically active segment of the Northern Sicily Continental margin (Southern Tyrrhenian Sea)
Authors: Zizzo Elisabetta , Sulli Attilio , Spatola Daniele , Gorini Christian , Gasparo Morticelli Maurizio
Published: March 2020

We investigate the tectonically active Northern Sicily Continental margin focusing on the neotectonics affecting the Offshore of Termini (Southern Tyrrhenian Sea) by using high-resolution seismic and multibeam data. The sedimentary succession along the North Sicilian Continental Margin (NSCM) represents the marine prolongation of those outcropping along the Northern Sicily coastal belt. The NSCM has been originated as a consequence of a complex interaction of compressional events, crustal thinning, and strike-slip faulting. E–W, NW–SE, and NE–SW trending, both extensional and compressional faults, with a local strike-slip component, exerted control on the morphology of the present-day shelf and coastal areas during the Pleistocene. During the Quaternary,  the tectonic as well as depositional events have strongly shaped the margin forming the actual complex geomorphic setting of the margin. We present the main results of a high resolution survey that allow to identify several features (e.g. Mass Transport Deposits and pockmarks) linked to gravitational mass movement and fluids escape processes strongly controlled by the tectonics affecting the NSCM. All over the study area, we mapped inside the Late Quaternary depositional sequence repeated and variously distributed MTDs, characterised by transparent/chaotic seismic facies, interbedded to hemipelagic deposits, with seismic facies showing subparallel seismic reflectors of the transgressive and high stand systems tracts. We infer that this MTDs have been seismically induced by earthquakes.  We estimate the recurrence times of earthquakes, by using an elaborate age-model that considers a constant sedimentation rate for the last 11.5 My, between 680 and 2200 years.
Suprathermal electron strahls. From small scale modeling to heliospheric implications
Authors: Lazar Marian
Published: March 2020

Recent advances in kinetic modeling reveal essential properties of the suprathermal populations opening perspectives for a realistic interpretation of their implications. Of particular importance are the suprathermal electron strahl (or beaming) populations, guided by the heliospheric magnetic field as kinetic-scale traces of the continuous solar outflows. We outline the main implications of the strahls by connecting their signatures in the velocity distributions with macroscopic properties of the solar wind, and processes conditioning their relaxation via coherent or non-coherent radiative emissions. The electron strahls may also help understanding major changes in the magnetic field topology in the outer corona, as shown by the most recent data from Solar Parker Probe, and during energetic (transient) events like coronal mass ejections, implying or not reconnection, but leading to strong interaction regions and shocks. 
The hydraulic conductivity of wounded xylem
Authors: Bonetti Sara , Breitenstein Daniel , Fatichi Simone , Domec Jean-Christophe , Or Dani
Published: March 2020

The xylem specific hydraulic conductivity (ks) is a key trait for the description of the plant’s ability to sustain the long-distance water transport required for transpiration. In this work, we systematically analyze xylem flow in several woody plants with contrasting anatomical traits combining flow experiments under different hydraulic pressure gradients. Results show a time and pressure dependence of ks similar to observations made a century ago by Dixon (1914). We mainly attribute the persistent drop in ks, accentuated with higher-pressure gradients, to a wounding response of the xylem tissues. Evidence suggests that wounded xylem tissue releases polysaccharides (prominently pectin) that gradually occlude xylem conduits. The macroscopic definition of K is further affected by complex microscopic xylem dynamics, with a key role of the xylem network topology, interconduit pit membrane flexibility, and redundancy of flow paths. These findings validate the picture of a complex and delicate conductive system whose hydraulic behavior goes beyond that of passive and inert deadwood. Notable implications for xylem conceptualization, measurements protocols, as well as ecosystem modeling applications are discussed.
The influence of sliding velocity and effective stress on the distribution of strain in subglacial till
Authors: Hansen Dougal , Daamsgard Anders , Zoet Lucas
Published: March 2020

The distribution of strain in actively deforming subglacial till is an important control on the sliding velocity and sediment transport of soft-bedded glaciers. In situ field observations, laboratory experiments, and numerical simulations have demonstrated that strain accumulation within subglacial till is often greatest at the ice-bed interface and decreases monotonically with depth, forming a convex-upward profile. However, the mechanisms that set the form of the profile and depth of deformation remain unconstrained. Here we systematically test the influence of two independent variables, effective stress and sliding velocity, on the distribution of strain in a fine-grained, sandy till emplaced beneath a layer of moving ice. Laboratory sliding experiments, conducted with a brand-new ring-shear device with a transparent sample chamber, are coupled with two suites of state-of-the-art numerical experiments using 1) a discrete element model and 2) a non-local granular fluidity continuum model designed to emulate till deformation. Five effective stresses and five sliding velocities are tested with the other parameter held constant (velocity and effective stress, respectively). For the ring shear experiments, images of the till bed are acquired at regular intervals, and we quantify the displacement of sediment grains that occurs between image captures using digital image correlation. These experiments represent the first instance where the deformation of till during glacier slip can be observed in real-time and linked directly to its controlling processes. Furthermore, they provide an opportunity to juxtapose the predictions of two new granular dynamic models against empirical observations in a controlled setting, providing an invaluable ground truth for future, larger-scale implementations simulating bedform genesis and soft-bedded glacier dynamics.