bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of Coupled FDM-DEM Approach on the Soil-Raft Foundation Interaction Subjected to Normal Faulting
Authors: Ru-Ya Fang , Cheng-Han Lin , Ming-Lang Lin
Published: March 2021

Recent earthquake events have shown that besides the strong ground motions, the coseismic faulting often caused substantial ground deformation and destructions of near-fault structures. In Taiwan, many high-rise buildings with raft foundation are close to the active fault due to the dense population. The Shanchiao Fault, which is a famous active fault, is the potentially dangerous normal fault to the capital of Taiwan (Taipei). This study aims to use coupled FDM-DEM approach for parametrically analyzing the soil-raft foundation interaction subjected to normal faulting. The coupled FDM-DEM approach includes two numerical frameworks: the DEM-based model to capture the deformation behavior of overburden soil, and the FDM-based model to investigate the responses of raft foundation. The analytical approach was first verified by three  benchmark cases and theoretical solutions. After the verification, a series of small-scale sandbox model was used to validate the performance of the coupled FDM-DEM model in simulating deformation behaviors of overburden soil and structure elements. The full-scale numerical models were then built to understand the effects of relative location between the fault tip and foundation in the normal fault-soil-raft foundation behavior. Preliminary results show that the raft foundation located above the fault tip suffered to greater displacement, rotation, and inclination due to the intense deformation of the triangular shear zone in the overburden soil. The raft foundation also exhibited distortion during faulting. Based on the results, we suggest different adaptive strategies for the raft foundation located on foot wall and hanging wall if the buildings are necessary to be constructed within the active fault zone. It is the first time that the coupled FDM-DEM approach has been carefully validated and applied to study the normal fault-soil-raft foundation problems. The novel numerical framework is expected to contribute to design aids in future practical engineering.

Keywords: Coupled FDM-DEM approach; normal faulting; ground deformation; soil-foundation interaction; raft foundation.
Groundwater assessment in the Mediterranean region: Regional modelling and in-situ data across scales
Authors: Ben-Salem Nahed , Reinecke Robert , Gómez-Hernández J. Jaime , Karatzas George , Rode Michael , Jomaa Seifeddine
Published: March 2021

Groundwater is a valuable resource throughout the world. It supplies the needs of many sectors everywhere. Providing high spatial resolution groundwater data is important for climatic, hydrological and agricultural applications, to ensure sustainable groundwater management. The scarcity of high-resolution groundwater data over large scales at the required accuracy is a significant limitation for such applications. This study was undertaken in the Mediterranean region, which is recognized as one of the world's most sensitive regions to water scarcity due to both climate change and consistently increasing anthropogenic pressures. Groundwater is considered a strategic freshwater reserve in the Mediterranean region; however, its status remains poorly characterized. This study investigates the feasibility of downscaling outputs of three global groundwater models (Reinecke et al. (2019), de Graaf et al. (2017) and Fan et al. (2013)) to higher resolution.

Steady-state results of the three models were compared with in-situ groundwater level observations, and an aggregation method was developed for downscaling. Observations from a long-term groundwater monitoring network over different regional studies around the Mediterranean were employed. Results showed that there is a significant discrepancy between the three compared model outputs. More specifically, the de Graaf et al. (2017) model presents a deeper water table than Reinecke et al. (2019) and Fan et al. (2013), while de Graaf et al. (2017) generally shows more significant variability in simulated water table depth. A detailed comparison between simulated and measured water table depth of different Mediterranean aquifers having different climatic, geologic and anthropogenic conditions will be presented.

The results of this work will contribute to advance the understanding of how to combine large-scale groundwater modelling with local in-situ data as a crucial tool to improve groundwater management in data-scarce regions.

This work was supported by the German Federal Ministry of Education and Research (BMBF, Germany, Grant 01DH19015) under the Project Sustain-COAST, co-funded by EU PRIMA 2018 programme.

 

References

­ Reinecke, R. et al. Challenges in developing a global gradient-based groundwater model (G3M v1.0) for the integration into a global hydrological model. Model Dev 12, 2401-2418 (2019).

­ de Graaf, I. et al. A global-scale two-layer transient groundwater model: Development and application to groundwater depletion. Water Resour 102, 53-67 (2017).

­ Fan, Y. et al. Global patterns of groundwater table depth. Science 339, 940-943 (2013).
Ionosphere comparison study of VGOS and global maps of Total Electron Content
Authors: Zubko Nataliya , Xu Minghui , Kareinen Niko , Savolainen Tuomas , Poutanen Markku
Published: March 2021

Ionosphere comparison study of VGOS and global maps of Total Electron Content.

Nataliya Zubko, Minghui Xu, Niko Kareinen, Tuomas Savolainen, Markku Poutanen.

 

Total Electron Content (TEC) of the ionosphere is an important characteristic whose accurate estimation is needed in various application which are based on measurements in radio wave band. There is a number of Global TEC models designed to describe conditions of ionosphere in different parts of the world. We have conducted a comparative study of the two selected TEC global maps with the results from the observations of the VLBI Global Observing System (VGOS). VGOS network has been established recently and it is continuously growing. The estimated differential TEC (dTEC) from VGOS data has high precision with the formal error of dTEC is of about 0.01-0.2 TECU. It can be used in evaluation of the TEC global maps, as well as an additional data source for the further improvement of the TEC map models.

VLBI measures radio waves emitted by Active Galactic Nuclei (AGN) using a network of radio telescopes distributed around the globe. The measured signal propagates through different parts of ionosphere having different local properties, since distances between radio telescopes spans the range from 400 km to more than 10,000 km. To account for the ionosphere delay effect, geodetic VLBI estimates dTEC for each observing baseline that is formed by a pair of radio telescopes.

Precision of the estimated dTEC with VGOS has been improved considerably compared to the traditional geodetic S/X VLBI observations. One needs to note that VGOS dTEC still have both instrumental (slowly varying) and source structure systematic contributions that will need to be decoupled from the ionosphere measurement. We have compared VGOS ionosphere product with the dTEC calculated using global ionosphere TEC maps. For analysis, we selected two TEC global models, CODE GIM and Neustrelitz TEC Model Global (NTCM-GL). The comparison was performed for the VGOS observations made in 2019, when the solar activity was at about its minimum. The comparison shows a good agreement between VGOS dTEC and dTEC obtained using global TEC maps. However, it also reveals shortages of the global TEC models in some locations. The VGOS data can be considered as an additional information source and, hence, they can be used for the further improvement of the global TEC models.
Characterizing the Dynamics of CME-Driven Coronal Bright Fronts Using The SPREAdFAST Framework 
Authors: Nedal Mohamed , Kozarev Kamen , Miteva Rositsa
Published: March 2021

In this work, we present a full characterization of over 50 historical Coronal Mass Ejection (CME)-driven compressive waves in the low solar corona, related to solar energetic particle events near Earth, using the Solar Particle Radiation Environment Analysis and Forecasting - Acceleration and Scattering Transport (SPREAdFAST) framework. SPREAdFAST is a physics-based, operational heliospheric solar energetic particle (SEP) forecasting system, which incorporates a chain of data-driven analytic and numerical models for estimating: a) coronal magnetic field from Potential Field Source Surface (PFSS) and Magnetohydrodynamics (MHD); b) dynamics of large-scale coronal (CME-driven) shock waves; c) energetic particle acceleration; d) scatter-based, time-dependent SEP propagation in the heliosphere to specific time-dependent positions. SPREAdFAST allows for producing predictions of SEP fluxes at multiple locations in the inner heliosphere, by modeling their acceleration at CMEs near the Sun, and their subsequent interplanetary transport. We used sequences of base-difference images obtained from the AIA instrument on board the SDO satellite, with 24-second cadence. We calculated time-dependent speeds in both the radial and lateral (parallel to the solar limb) directions, mean intensities and thicknesses of the fronts, and major and minor axes. This is essential for characterizing the SEP spectra near the Sun. The kinematics measurements were used to generate time-dependent 3D geometric models of the wave fronts and time-dependent plasma diagnostics using MHD and DEM model results.

 

 
Simulated biogeochemical effects of idealized land cover and land management changes
Authors: Guo Suqi , Pongratz Julia , Havermann Felix , De Hertog Steven , Thiery Wim , Manola Iris , Coumou Dim , Lejeune Quentin , Schleussner Carl-Friedrich
Published: March 2021

Land cover and land management (LCLM) changes are important sources and sinks for anthropogenic CO2 fluxes. Current earth system models (ESMs) are capable to simulate the globally most sensitive LCLM changes (strong effects or large spatial extent in the earth system) such as de- and afforestation, wood harvest and irrigation, however, a comprehensive analysis between these ESMs is still absent. The present study aims to quantify the biogeochemical effects of forest cover changes, wood harvesting and irrigation of croplands on the global carbon cycle.

 

Therefore, we conducted coupled atmosphere-ocean-land experiments of idealized global deforestation with and without cropland irrigation as well as global re-/afforestation with and without wood harvest over a 150-year period under present day solar and trace gas forcing. All experiments were simulated by three different ESMs (MPI-ESM, EC-EARTH and CESM) to quantify inter-model uncertainty and potentially uncover specific model biases. The analysis focuses on the transient response of land carbon fluxes and pools after an abrupt LCLM practice change, in order to track the emergence of signals that could potentially mitigate climate change. Additionally, we want to unravel model differences concerning the temporal dynamics of LCLM change effects. Since greenhouse gases (GHG) concentration is kept constant at present-day level, the climate changes here arise from the biogeophysical effects of LCLM changes. We use a checkerboard approach to separate local and non-local components of the climate changes as proposed by Winckler et al., 2017, i.e. we separate the changes in climate induced locally by the LCLM changes from those induced remotely by advection and changes in atmospheric circulation.

 

First results with the MPI-ESM show that immediate global deforestation starting from present-day land-use distribution causes a 824 GtC loss of the total land carbon pool throughout the simulation period of 150 years, about 46% of which stem from tropical regions (17°S–17°N). Land carbon stocks are not balanced until the end of the simulation, which indicates that the land will continue to emit CO2 to the atmosphere and a long-term commitment by deforestation for climate change. Non-local effects lead to a loss of 26 GtC from land, again with largest losses found for the tropical regions. Even though it is a small part compared to the total loss (local plus non-local effect), it reveals potentially substantial consequences that LCLM changes at large scale can have unintendedly on other regions, including remote pristine ones, through biogeophysical climate change.
Microseismicity in the Eastern Alps: Preliminary Results From the Swath-D Network
Authors: Hofman Rens , Kummerow Joern , Cesca Simone , Wassermann Joachim , Plenefisch Thomas ,   AlpArray Working Group
Published: March 2021

The AlpArray seismological experiment is an international and interdisciplinary project to advance our understanding of geophysical processes in the greater Alpine region. The heart of the project consists of a large seismological array that covers the mountain range and its surrounding areas. To understand how the Alps and their neighbouring mountain belts evolved through time, we can only study its current structure and processes. The Eastern Alps are of prime interest since they currently demonstrate the highest crustal deformation rates. A key question is how these surface processes are linked to deeper structures. The Swath-D network is an array of temporary seismological stations complementary to the AlpArray network located in the Eastern Alps. This creates a unique opportunity to investigate high resolution seismicity on a local scale.

In this study, a combination of waveform-based detection methods was used to find small earthquakes in the large data volume of the Swath-D network. Methods were developed to locate the seismic events using semi-automatic picks, and estimate event magnitudes. We present an overview of the methods and workflow, as well as a preliminary overview of the seismicity in the Eastern Alps.
New palynological data from the East Tasman Plateau (ODP Site 1172) indicate rapid earliest Oligocene warming.
Authors: Amoo Michael , Salzmann Ulrich , Bijl Peter K. , Thompson Nick
Published: March 2021

Considered as one of the most significant climate reorganisations of the Cenozoic period, the Eocene-Oligocene (E/O) Transition (ca. 33.9-33.5 Ma) is characterised by global cooling coupled with glacial advance on Antarctica. Combined micropalaeontological (diatom and dinoflagellate) and sedimentological evidence hint of regional reorganisation of ocean currents around Antarctica, in association with the Eocene-Oligocene transition. The late Eocene to early Oligocene deepening of the Tasman Gateway resulted in the flow of warm surface waters from the Australo-Antarctic gulf into the southwestern Pacific Ocean.  However, the extent and effect of these changes in ocean circulation on regional terrestrial climate and vegetation across the E/O Transition is not readily known. Here, we present new well-dated, high resolution palynological (sporomorph) data from the East Tasman Plateau (ODP Site 1172) to reconstruct climate and vegetation dynamics from the late Eocene through to the early Oligocene. Results from our sporomorph data point to four vegetation communities occupying Tasmania under different precipitation and temperature regimes: (i) Paratropical rainforest along the coastlines and temperate rainforests at higher altitude of the hinterlands from 37.97-37.52 Ma; (ii) cool temperate forest expanding into areas previously occupied by the paratropical forests between 37.306-35.60 Ma; (iii) a complex mix of paratropical associations coexisting with frost-tolerant taxa, followed by a period of relative stability shown in the dominance of cold-temperate taxa from 35.50-33.36 Ma; (iv) a warm temperate forest present in the early Oligocene (33.25-33.06 Ma). Our sporomorph record showed a general cooling trend from the latest-middle Eocene to the late Eocene (37.97-35.60 Ma), fluctuations between warm and cold climates (35.50 – 34.19 Ma), a period of relative stable cooling across the E/O transition (33.94-33.5 Ma), and a rather unusual rapid warming right after the E/O transition (earliest Oligocene; 33.36 - 33.06 Ma). Our quantitative estimates of terrestrial temperature change and palaeoecological reconstructions show a close link with previously published dinoflagellate cyst data from this same study site, suggesting a possible vegetation and climate response to tectonic changes (most likely the tectonic opening and deepening of the Tasman Gateway ca. 35.5 Ma) and relative short-term regional reorganisation of ocean currents.

Keywords: Antarctica, Eocene-Oligocene Transition, sporomorph, temperate rainforest, Tasman Gateway
Intercomparison of Phytoplankton functional types dynamics from satellite observations
Authors: Bretagnon Marine , Alvain Séverine , Bracher Astrid , Garnesson Philippe , losa Svetlana , Mangin Antoine , Rêve Anne-Hélène , Uitz Julia , Xi Hongyan , Hembise Fanton d'Andon Odile
Published: March 2021

Copernicus marine environment monitoring service (CMEMS) gives users access to a wide range of ocean descriptors. Both physics and biogeochemistry of the marine environment can be studied with complementary source of data, such as in situ data, modelling output and satellite observations at global scale and/or for European marginal seas. Among the ocean descriptors supplied as part of CMEMS, phytoplankton functional types (PFTs) describe the phytoplanktonic composition at global level or over European marginal seas. Studied phytoplankton assemblage is particularly important as it is the basis of the marine food-web. Composition of the first trophic level is a valuable indicator to infer the structure of the ecosystem and its health. Over the last decades, ocean colour remote sensing has been used to estimate the phytoplanktonic composition. The algorithms developed to estimate PFTs composition based on ocean colour observation can be classified in three categories: the spectral approaches, the abundance-based approaches (derived from the chlorophyll concentration) and the ecological approaches. The three approaches can lead to differences or, conversely, to similar patterns. Difference and similarity in PFTs estimation from remote sensing is a useful information for data assimilation or model simulation, as it provides indications on the uncertainties/variability associated to the PFT estimates. Indeed, PFT estimates from satellite observations are increasingly assimilated into ecological models to improve biogeochemical simulations, what highlights the importance to get an index or at least information describing the validity range of such PFTs estimates.

In this study, four algorithms (two abundance-based, and two spectral approaches) are compared. The aim of this study is to compare the related PFT products spatially and temporally, and to study the agreement of their derived PFT phenology. This study proposes also to compare PFT algorithms developed for the global ocean with those developed for specific regions in order to assess the potential strength and weakness of the different approaches. Once similarities and discrepancies between the different approaches are assessed, this information could be used by model to give an interval of confidence in model simulation.
Influence of non-tidal atmospheric and oceanic loading deformation on the stochastic properties of over 10,000 GNSS vertical land motion time series
Authors: Gobron Kevin , Rebischung Paul , de Viron Olivier , Van Camp Michel , Demoulin Alain
Published: March 2021

Over the past two decades, numerous studies demonstrated that the stochastic variability in GNSS position time series – often referred to as noise – is both temporally and spatially correlated. The time correlation of this stochastic variability can be well approximated by a linear combination of white noise and power-law stochastic processes with different amplitudes. Although acknowledged in many geodetic studies, the presence of such power-law processes in GNSS position time series remains largely unexplained. Considering that these power-law processes are the primary source of uncertainty for velocity estimates, it is crucial to identify their origin(s) and to try to reduce their influence on position time series.

 

Using the Least-Squares Variance Component Estimation method, we analysed the influence of removing surface mass loading deformation on the stochastic properties of vertical land motion time series (VLMs). We used the position time series of over 10,000 globally distributed GNSS stations processed by the Nevada Geodetic Laboratory at the University of Nevada, Reno, and loading deformation time series computed by the Earth System Modelling (ESM) team at GFZ-Potsdam. Our results show that the values of stochastic parameters, namely, white noise amplitude, spectral index, and power-law noise amplitude, but also the spatial correlation, are systematically influenced by non-tidal atmospheric and oceanic loading deformation. The observed change in stochastic parameters often translates into a reduction of trend uncertainties, reaching up to -75% when non-tidal atmospheric and oceanic loading deformation is highest.
Retrieval of Stable Water Vapour Isotopologues from the TROPOMI Instrument
Authors: Trent Tim , Boesch Hartmut , Somkuti Peter , Schneider Mathhias , Khosrawi Farahnaz , Diekmann Christopher , Röhling Amelie , Sodemann Harald , Thurnherr Iris
Published: March 2021

Atmospheric moisture is a crucial factor for the redistribution of heat in the atmosphere, with a strong coupling between atmospheric circulation and moisture pathways responsible most climate feedback mechanisms. Conventional satellite and in situ measurements provide information on water vapour content and vertical distribution; however, observations of water isotopologues make a unique contribution to a better understanding of this coupling.

In recent years, observations of water vapour isotopologue from satellites have become available from nadir thermal infrared measurements (TES, AIRS, IASI) which are sensitive to the free troposphere and from shortwave-infrared (SWIR) sensors (GOSAT, SCIAMACHY) that provide column-averaged concentrations including sensitivity to the boundary layer. The TROPOMI instrument on-board Sentinel 5P (S5p) measures SWIR radiance spectra that allow retrieval of water isotopologue columns but with much improved spatial and temporal coverage compared to other SWIR sensors promising a step-change for scientific and operational applications.

Here we present the retrieval algorithm development for stable water isotopologues from TROPOMI as part of the ESA S5p Innovation programme.  We also discuss the validation of these types of satellite products with fiducial in situ measurements, and challenges compared with other satellite measurements. Finally, we outline the roadmap for assessing the impact of TROPOMI data against state-of-the-art isotope enabled models.
Non-uniqueness in the inversion of volcano deformation data: change of volume or change of position?
Authors: Ronchin Erika , Castaldo Raffaele , Pepe Susi , Tizzani Pietro , Solaro Giuseppe , Battaglia Maurizio
Published: March 2021

The detailed spatial and temporal information of surface deformation detected during volcanic unrest by InSAR images suggests a degree of complexity of volcanic systems (e.g., source geometries and distribution of material properties) that cannot be correctly represented by simple models of a pressure source embedded in an elastic, homogeneous, isotropic half-space.

The inversion of deformation data, performed for the characterization of the source of deformation, is based on the model we choose to represent the volcanic system. Therefore the quality of the chosen model influences the source size and its temporal changes estimated through the inversion, and thus their interpretation. In fact, our assumptions about geometries and/or magma and rock properties affect the estimations of changes in magma volumes and reservoir pressure. To obtain a more reliable interpretation of surface signals, it is thus paramount to have more realistic models, where the distribution of material properties is constrained by multiple data sets, with greater flexibility in the definition of sources in space and time.

Assuming we could invert InSAR data with models that can deal with a complex and arbitrarily shaped deformation source, how unique could this solution be? How much could we say about the evolution of the deformation source over time? Furthermore, how much information about the spatial complexity of the source and its evolution in space and time would be missed?

To answer these questions, we characterize the deformation source from the inversion of InSAR data based on a finite element method (FEM) forward model without an a-priori source geometry. The deformation source is bound by estimating the strength of an amorphous cluster of deformation sources distributed over a grid. This uses the principle of superposition already applied to point or cuboid volume elements, embedded in a homogeneous half-space. Also, the numerical model integrates the cluster-source with a heterogeneous distribution of material properties and the topography.

In our study, we quantify the ambiguity in the estimation of arbitrary geometries of sources of deformation composed by clusters of Finite Element Method unit sources distributed over a grid. The regularized least-squares solutions of the steady-state PDEs inverse model are obtained using a COMSOL Multiphysics-based routine. Through the inversion of the InSAR time series of the unrest at Uturuncu volcano (Bolivia), we quantify the ability of the employed cluster-source approach to identify the changes of deformation sources in time. 

This research is financed by an individual fellowship of the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 793811.
Investigating the impact of the Pleistocene sea-level lowstand on offshore fresh groundwater on the New Jersey shelf 
Authors: Thomas Ariel , Reiche Sönke , Clauser Christoph
Published: March 2021

Offshore fresh groundwater reservoirs have been identified on continental shelves in several regions of the world. In many cases, sea-level change over geologic time-scales has been identified as a key factor in the emplacement of these freshwater systems. This numerical study analyzes a range of paleo-hydrogeological conditions on the New Jersey transect during the late Pleistocene, during which vast sections of the shelf were sub-aerially exposed. Coupled variable-density flow and heat transport simulations were conducted on a geologically representative 2D shelf model using SHEMAT-Suite. The model combines sequence stratigraphic interpretation of 2D depth migrated seismic lines and a stochastic facies distribution, with petrophysical properties derived from IODP Expedition 313 well data. The study considers a 60000 year period of surface meteoric recharge, and the subsequent marine transgression from 12 000 years ago to present-day. A sensitivity analysis is conducted for key factors that influence offshore freshened groundwater emplacement during recharge phase: (1) topography-driven flow, and (2) permeability anisotropy. Systematically introducing anisotropy resulted in a 11 % – 31 % decrease in emplaced volume relative to the base-case. The results were analysed to determine whether the late Pleistocene sea-level lowstand drove enough freshwater emplacement that can explain the complex present-day observations. All of the simulated scenarios indicate that surface recharge lead to freshening of sediments across the entire transect during this period, even in case of high permeability anisotropy. The observations also suggest that the cyclical flushing and re-salinification of shelf sediments that takes place over glacial – interglacial cycles is an asymmetrical process, which favours storage of freshened pore fluid in the long run.
Large recent counterclockwise rotations in the Tajik Basin and implications on the Pamir salient formation
Authors: Li Lin , Dupont-Nivet Guillaume , Roperch Pierrick , Najman Yani , Kaya Mustafa , Meijer Niels , Aminov Jovid
Published: March 2021

Contrasting models have been proposed to explain the formation of the Pamir salient: either largely inherited from a Mesozoic arcuate structure or recently formed by Indian northward indentation and possibly related to syn-orogenic lateral extrusion. The vertical-axis counterclockwise rotations observed in the Tajik Basin are key constraints on testing these models, but the timing of these rotations remains hindered by poor age control on the basin sediments. We report a combined analysis of vertical-axis rotation and magnetostratigraphic dating of a long sedimentary section in the eastern Tajik Basin, which yields strong counterclockwise rotations (~56°) in early Late Cretaceous to late Miocene strata. This result suggests that rotation in the Tajik Basin occurred after ~8 Ma, much later than previously suggested. Combining with a regional compilation of previous paleomagnetic studies as well as structural and GPS constraints including Pamir and Tarim, we explore potential implications on models of the Pamir salient. We infer that after 8 Ma (probably even later), the Pamir (North, Central, and South) began to overthrust west- and northwest-ward, causing counterclockwise rotations in the Tajik Basin. This reconstruction allows for ~150 km of post-8 Ma northwestward indentation into the Tajik Basin, in agreement with coeval underthrusting of the Indian mantle lithosphere into Asia.
Identification of Kelvin-Helmholtz vortices at the Earth’s magnetosphere
Authors: Settino Adriana , Perrone Denise , Khotyaintsev Yuri V. , Graham Daniel B. , Pezzi Oreste , Malara Francesco , Valentini Francesco
Published: March 2021

Kelvin-Helmholtz instability is a widespread phenomenon in space plasmas, such as at the planetary magnetospheres. During its nonlinear phase, the generation of Kelvin-Helmholtz vortices takes place. The identification of such coherent structures is not straightforward in observational data contrary to numerical simulations where both temporal evolution and spatial behavior can be observed. Recently, a comparison between a hybrid Vlasov-Maxwell simulation and Magnetospheric Multi-Scale satellites observation of a Kelvin-Helmholtz event has shown the presence of kinetic features that can uniquely characterize the boundaries of Kelvin-Helmholtz vortices.  Indeed, a strong total current density has been observed in correspondence of the edges of each vortex associated with a weakly distorted distribution function from the equilibrium distribution; while the opposite occurs inside the vortex region. Moreover, a new tool has been proposed to distinguish the different phases of the Kelvin-Helmholtz instability and to identify the trajectory of the spacecraft across the vortex itself. Such a tool takes into consideration the mixing degree between the magnetospheric-like and magnetosheath-like particles population in the Earth environment. The clear identification of a vortex in in situ data is an important achievement since it can provide a better understanding of the role that Kelvin-Helmholtz instability plays in weakly collisional space plasmas in the contest of energy dissipation.

This work has received funding from the European Unions Horizon 2020 research and innovation programme under grant agreement no. 776262 (AIDA,).
The core of the Baltic CIL: shall we introduce the Bornholm Intermediate Water?
Authors: Bukanova Tatiana , Lobchuk Olga , Chubarenko Irina
Published: March 2021

Cold Intermediate Layer (CIL) is apparent in the thermohaline structure of the Baltic Sea every year, typically from April to December. Within the CIL, water temperature, salinity, oxygen content, and other parameters are highly inhomogeneous in vertical, reflecting a complicated process of its formation. The core of the CIL (the layer of the coldest waters) has its T,S-index) allowing to identify the south-western part of the sea as the source of these waters. At the beginning of spring warming, a combination of environmental factors favors the subduction of the cold surface waters into the intermediate layers of the Baltic Proper, where they adjust to the density field, making up the coldest layer right above the permanent pycnocline.

For spring 2006, CTD measurements from 2 expeditions of research vessels “Professor Shtokman” of the Shirshov Institute of Oceanology and “Gauss” of Leibniz Institute for Baltic Sea Research in Warnemünde (IOW) were analyzed, along with the CTD measurements from ICES open database, and meteorological information. Remote sensing data provide observations of the abrupt transformation of SST field in the Bornholm Basin in early spring 2006, when the coldest surface water occurred within the coastal zones and its temperature was close to or below the temperature of maximum density (Tmd). The beginning of spring warming in the region and further heating of the cold surface water from temperature below the Tmd induce horizontal exchange, which favors the penetration of winter-cold (1.1–2.1 °C) surface waters of moderate salinity (7.6-8.1) into the intermediate layers in March. This water was observed in the Gdansk and Gotland basins in April-May 2006 as the core of the CIL. On the basis of vertical T,S-profiles and T,S-diagrams, the range of parameters of the CIL core waters in spring 2006 was determined (T: 1.4–2.1 °C; S: 7.6–8.1), which corresponds to the upper mixed layer in the vicinity of the Bornholm Island in March, 2006. Since this relation has already been confirmed for other years, and having in mind the importance of the process of the CIL formation for the entire Baltic Sea conveyor belt, we suggest to term waters of the CIL core as the Bornholm Intermediate Waters (BIW). Obviously, the T,S-index of the BIW shall vary from year to year, reflecting the severity of the past winter and the conditions of the particular spring. However, the BIW location right above the pycnocline, the lowest (for the current year) temperature, and its characteristic salinity of 7.6-8.1 seem to be repeatedly confirmed by field observations in the Baltic Proper in spring.

Investigations are supported by the Russian Foundation for Basic Research, grant No. 19-05-00717 (in part of the data analysis) and the State Assignment No. 0149-2019-0013 (in part of satellite data collecting and processing).
Predicting Solute Transport in Soil Water Flow with Estimated, Effective Material Properties
Authors: Riedel Lukas , Bauser Hannes Helmut , Maiwald Robert , Ospina De Los Ríos Santiago
Published: March 2021

Soil water flow is a key hydrological process supporting several ecosystem services. The non-linear soil hydraulic material properties have a profound influence on the flow dynamics and cannot be measured directly. They can be estimated with data assimilation based on measurements of the soil hydraulic state. As soils feature a multi-scale architecture, these measurements typically cannot resolve the soil heterogeneity on the relevant spatial and estimating it becomes difficult. In a previous study, we estimated a one-dimensional effective representation of a synthetic, two-dimensional, heterogeneous domain based on a vertical measurement profile using an ensemble Kalman filter. The estimated one-dimensional model represented the dynamics of the soil water movement sufficiently well, but it remained unclear if these results can be transferred to associated physical processes.

Soil water flow also transports solutes between surface and groundwater. The accurate description of solute fluxes and concentrations is crucial for predicting groundwater quality and contamination. In this study, we use the aforementioned estimated, one-dimensional representation of the domain to simulate and forecast passive solute transport within the soil water flow. We examine its predictive capabilities by comparing these results with results obtained from the two-dimensional, heterogeneous synthetic truth from which artificial measurements are extracted.
Gas and heat fluxes during multiple effusive eruptions of Piton de la Fournaise (Réunion) and their implications for magmatic processes
Authors: Verdurme Pauline , Carn Simon , Harris Andrew , Coppola Diego , Di Muro Andrea , Arellano Santiago , Gurioli Lucia
Published: March 2021

Piton de la Fournaise (La Réunion, France) is one of the most active volcanoes in the world, producing frequent effusive basaltic eruptions of varying duration. These eruptions are accompanied by strong thermal infrared (TIR) signals and significant sulfur dioxide (SO2) emissions detected by satellite instruments. The high frequency of eruptions provides an extensive dataset, which allows us to explore the relationships between eruptive heat, mass and gas fluxes. Five eruptions with different temporal trends of erupted mass flux have been selected for this study: April 2007, May 2015, August-October 2015, February 2019 and April 2020. For each of them, we estimated SO2 emission from three ultraviolet satellite instruments (the Ozone Monitoring Instrument OMI, the Ozone Mapping and Profiler Suite OMPS and the Tropospheric Monitoring Instrument TROPOMI). The total SO2 emission for each eruption has been estimated for an extensive range of sulfur (S) content within melt inclusions and the matrix using a petrological approach and the erupted magma masses obtained from MODIS TIR satellite data. Preliminary results show that, assuming the estimated SO2 emission falls within the 30% error of the SO2 mass detected by each satellite instrument, the implied magmatic sulfur contents are in good agreement with expected values for basaltic eruptions. Given pre-eruptive S contents between 200 and 750 ppm, estimated SO2 emissions for the May 2015 eruption are consistent with an eruption largely fed by degassed magma. However, for the February 2019 eruption, there is a discrepancy between the three satellite sensors. Whereas the TROPOMI and the OMI instruments provide almost the same range of magmatic sulfur content (300-1100 ppm), the OMPS gives a higher range (700 to 1900 ppm) suggesting that fresh, undegassed magma was also involved in this eruption. Petrologic analysis of the pre-eruptive sulfur content will allow us to validate the satellite data and, in turn, to validate the ground-based SO2 data from the NOVAC network operated by the Observatoire Volcanologique du Piton de la Fournaise (OVPF). Our approach yields insights into the characteristics of the magma reservoir supplying effusive events (e.g., eruptive degassing processes and the ratio of intrusive to extrusive magma) from space-based sensors.
INNOVATIVE DEVELOPMENTS IN THE FIELD OF TECHNOLOGY AND EQUIPMENT FOR
PRODUCTION OF COMPOSITE FIBER MATERIALS
Authors: Khosrovyan А.G. , Khosrovyan I.G. , Khosrovyan G.A.
Published: March 2021

The issues of obtaining composite fibrous materials based on the development of technology,
equipment and a method for obtaining multilayer fibrous materials are considered. The advantages of the
developed technologies, equipment and methods for producing composite fibrous materials are noted. Variants of
obtaining composite fibrous materials are given, depending on the feedstock and their field of application. The
results of theoretical studies of technological processes taking place on the developed equipment for obtaining
multilayer fibrous materials are presented.
MENINGKATKAN HASIL BELAJAR IPA DI KELAS VI SD NEGERI 62/II PADANG LALANG DENGAN PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE TAI (TEAM ASSISTED INDIVIDUALIZATION)
Authors: ASMAWATI ASMAWATI
Published: March 2021

Penelitian ini bertujuan untuk mengetahui keefektifan model pembelajaran Kooperatif Tipe TAI (Team Assisted Individualization). Dari hasil-hasil penelitian dilakukan pembelajaran tentang konduktor dan isolator dengan menggunakan model pembelajaran Kooperatif Tipe TAI (Team Assisted Individualization). Secara khusus bahwa pembelajaran dengan menggunakan model pembelajaran Kooperatif Tipe TAI (Team Assisted Individualization) lebih meningkatkan hasil belajar, penggunaan model pembelajaran Kooperatif Tipe TAI (Team Assisted Individualization) membuat kegiatan pembelajaran lebih menyenangkan, siswa terlibat aktif dan siswa menguasai pembelajaran. Pada siklus I sebanyak 5 orang (29,41%) yang mengajukan pendapat dan pada siklus II meningkat menjadi  13 orang (76,47 %). Siswa yang aktif dalam diskusi juga meningkat yaitu pada siklus I sebanyak 6 orang (35,29%) dan meningkat pada siklus II meningkat menjadi 14 orang (82,35%).Kemudian aktivitas menjawab pertanyaan juga meningkat pada siklus I sebanyak 6 orang (35,29 %) dan pada siklus II meningkat menjadi 15 orang (88,23 %). Kemudian aktivitas membantu mengerjakan tugas juga meningkat yaitu sebanyak 11 orang pada siklus I kemudian sebanyak 17 orang (100%) pada siklus II. Jadi model pembelajaran Kooperatif Tipe TAI (Team Assisted Individualization) efektif untuk meningkatkan aktivitas dna hasil belajar siswa.
UPAYA MENINGKATKAN HASIL BELAJAR MATEMATIKA MELALUI MODEL PEMBELAJARAN KOOPERATIF TIPE STAD PADA PESERTA DIDIK KELAS IX 2 SMP NEGERI 01 MUARA BUNGO
Authors: Sari Siti Komala
Published: March 2021

Masalah dalam penelitian ini adalah hasil belajar peserta didik  masih rendah dan belum mencapai harapan. Rendahnya hasil belajar peserta didik pada mata pelajaran Matematika ini diduga disebabkan oleh ketidaksesuaian model pembelajaran yang digunakan guru dalam pembelajaran Matematika. Model ceramah yang biasa digunakan guru dalam mengajar merupakan pembelajaran satu arah, sehingga cenderung membuat peserta didik menjadi pasif dalam belajar. Jenis penelitian ini Penelitian ini merupakan penelitian tindakan kelas (classroom action research). Sampel yang diambil berjumlah sebanyak 28 orang. Teknik pengambilan sampel dilakukan dengan “total Sampling”. Teknik pengumpulan data menggunakan tes dan observasi. Hasil penelitian hasil peneilitian ini menunjukkan bahwa pembelajaran dengan menggunakan model pembelajaran kooperatif tipe STAD memiliki dampak positif dalam meningkatkan hasil belajar peserta didik. Hal ini dapat dilihat dari semakin mantapnya pemahaman dan penguasaan peserta didik terhadap materi yang telah disampaikan guru selama ini (ketuntasan belajar meningkat dari sklus I, dan II yaitu masing-masing 67,85%, dan 92,85%.
UPAYA PENINGKATAN AKTIVITAS SISWA PADA PEMBELAJARAN PENDIDIKAN KEWARGANEGARAAN DENGAN PENDEKATAN CONTEXTUAL TEACHING AND LEARNING DI SMP NEGERI 7 MUARA BUNGO TAHUN PELAJARAN 2017/2018
Authors: Zuryati Zuryati
Published: March 2021

Penelitian ini berlatar belakang dari aktivitas siswa dalam pembelajaran PKn yang kurang aktif berpartisipasi dikarenakan hanya terjadi pemberian informasi dari guru ke siswa. Sehingga siswa kurang bersemangat dan terlihat bias saat proses pembelajaran. Penelitian ini bertujuan untuk meningkatkan aktivitas siswa dalam pembelajaran PKn melalui pendekatan Contextual Teaching and Learning (CTL) pada siswa kelas IX1 Semester genap tahun pelajaran 2017/2018 di SMP Negeri 7 Muara Bungo. Jenis Penelitian ini adalah penelitian tindakan kelas (PTK) dengan pendekatan deskriptif kualitatif yang dilaksanakan dalam dua siklus. Hasil penelitian menunjukkan bahwa penerapan Contextual Teaching And Learning pada pembelajaran PKn dapat meningkatkan aktivitas siswa sebesar 82.8% atau rata-rata 5.88. aktivitas belajar siswa yang meningkat dari siklus I ke siklus II diantaranya a) kemampuan menjawab pertanyaan 26.6%, b) menyampaikan pertanyaan 14.8%, c) kemampuan dalam mengungkapkan pendapat 17.7%, d) keterampilan dalam memberikan saran 8.9% dan e) kemampuan dalam mengungkapkan kesimpulan 14.8%.
Adverbs of Time in Arabic and English: Comparative Study
Authors: Mehdi Mohamed Farhat , Jaradat Mazen
Published: March 2021

Adverbs are words that are used to change, modify or qualify several types of other words including adjectives, verbs, or other adverbs. There are five basic types of adverbs in the English language, namely that of Manner, Time, Place, Frequency, and Degree. In the Arabic language, there are just two adverbs namely that of Time and Place. This research aimed to prove that the adverb of time exists in both Arabic and English languages and to compare and state the similarities and differences between the two languages. Most importantly, to show which were more the similarities or the differences? The results showed that the similarities were more than the differences despite the fact that the two languages are not from the same family.
Los museos etnológicos como instrumentos de formación ciudadana para la sostenibilidad
Authors: Redondo Castillo Laura , Vilches Pena Amparo , Gil-Pérez Daniel
Published: March 2021

La investigación que se presenta estudia el papel que los museos etnológicos pueden jugar en la educación científica para contribuir a sociedades más sostenibles, dado que dichos museos pretenden mostrar aspectos esenciales de la vida de los grupos humanos y las relaciones que se establecen entre ellos y el medio que les rodea. Pueden ser así un instrumento idóneo para abordar, tanto los problemas locales que afectan a un grupo humano concreto, como los globales a los que ha de hacer frente la humanidad. Se ha analizado en qué medida el contenido de los museos etnológicos incorpora la problemática socioambiental y, a la luz de dicho análisis, se han diseñado herramientas –entre ellas un museo virtual– para contribuir a la formación para la sostenibilidad, evaluando los resultados de su utilización, con profesorado de ciencias en formación y estudiantes de secundaria.
«De STEM nos gusta todo menos STEM». Análisis crítico de una tendencia educativa de moda
Authors: Toma Radu Bogdan , García-Carmona Antonio
Published: March 2021

En este artículo se presenta un análisis crítico sobre los desafíos y limitaciones de propuestas e investigaciones didácticas enmarcadas en el movimiento STEM. Se argumenta que la mayoría de las propuestas didácticas catalogadas como STEM son educativamente deficitarias, además de poco novedosas respecto de planteamientos anteriores para la enseñanza de las ciencias, la tecnología y las matemáticas. Se cuestiona también la viabilidad de un enfoque STEM en el contexto educativo español, y se discute sobre el uso abusivo del término, empleado a menudo como eslogan para atraer financiación, o hacer propaganda de iniciativas y materiales educativos añosos, rebautizados ahora como STEM. Se finaliza con una reflexión sobre la necesidad de un proceso de validación didáctica riguroso que oriente sobre las posibilidades y limitaciones de una enseñanza STEM.
COVID-19 Pandemic—Did We Sign Up for “This”?
Authors: Aggarwal Nitish , Boppana Tarun , Mittal Saurabh
Published: March 2021

Since the beginning of the pandemic, there is an increasing pressure on our healthcare systems to cope with the increasing workload [...]