bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the response of non-perennial streams to climate change impact: The Bouregreg watershed in Morocco
Authors: De Girolamo Anna Maria , Brouziyne Youssef , Benaabidate Lahcen , Aboubdillah Aziz , El Bilali Ali , Bouchaou Lhoussaine , Chehbouni Abdelghani
Published: March 2021

The non-perennial streams and rivers are predominant in the Mediterranean region and play an important ecological role in the ecosystem diversity in this region. This class of streams is particularly vulnerable to climate change effects that are expected to amplify further under most climatic projections. Understanding the potential response of the hydrologic regime attributes to climatic stress helps in planning better conservation and management strategies. Bouregreg watershed (BW) in Morocco, is a strategic watershed for the region with a developed non-perennial stream network, and with typical assets and challenges of most Mediterranean watersheds. In this study, a hybrid modeling approach, based on the Soil and Water Assessment Tool (SWAT) model and Indicator of Hydrologic Alteration (IHA) program, was used to simulate the response of BW's stream network to climate change during the period: 2035-2050. Downscaled daily climate data from the global circulation model CNRM-CM5 were used to force the hybrid modeling framework over the study area. Results showed that, under the changing climate, the magnitude of the alteration will be different across the stream network; however, almost the entire flow regime attributes will be affected. Under the RCP8.5 scenario, the average number of zero-flow days will rise up from 3 to 17.5 days per year in some streams, the timing of the maximum flow was calculated to occur earlier by 17 days than in baseline, and the timing of the minimal flow should occur later by 170 days in some streams. The used modeling approach in this study contributed in identifying the most vulnerable streams in the BW to climate change for potential prioritization in conservation plans.
What can we learn from observed temperature and salinity isopycnal anomalies at eddy generation sites?  Application in the Tropical Atlantic Ocean.
Authors: Aguedjou Habib Micaël , Chaigneau Alexis , Dadou Isabelle , Morel Yves , Pegliasco Cori , Da-Allada Casimir Y. , Baloïtcha Ezinvi
Published: March 2021

Potential vorticity (PV) is a key parameter to analyze the generation and dynamics of mesoscale eddies. Numerical studies have shown how adiabatic (displacement of particles within a background gradient of PV) and diabatic (diapycnal mixing and friction) processes can be involved in the generation of localized PV anomalies and vortices. Such processes are however difficult to evaluate in the ocean because PV is difficult to evaluate at mesoscale. In this study, we argue that qualitative analysis can be done, based on the link between PV anomalies and isopycnal temperature/salinity anomalies (Ɵ’/S’). Indeed, in the ocean, eddies created by diapycnal mixing or isopycnal advection of water-masses, are associated with PV anomalies and significant isopycnal Ɵ’/S’. In contrast, eddies created by friction are associated with PV anomalies but without isopycnal Ɵ’/S’. In this study, based on 18 years of satellite altimetry data and vertical Ɵ/S profiles acquired by Argo floats, we analyze the isopycnal Ɵ’/S’ within new-born eddies in the tropical Atlantic Ocean (TAO) and discuss the possible mechanisms involved in their generation. Our results show that on density-coordinates system, both anticyclonic (AEs) and cyclonic (CEs) eddies can exhibit positive, negative, or non-significant Ɵ’/S’. Almost half of the sampled eddies do not have significant Ɵ’/S’ at their generation site, indicating that frictional effects probably play a significant role in the generation of their PV anomalies. The other half of eddies, likely generated by diapycnal mixing or isopycnal advection, exhibits significant positive or negative anomalies with typical Ɵ’ of ±0.5°C. More than 70% of these significant eddies are subsurface-intensified, having their cores below the seasonal pycnocline. Refined analyses of the vertical structure of new-born eddies in three selected subregions of the TAO where the strongest anomalies were observed, show the dominance of cold (warm, respectively) subsurface AEs (CEs) likely due to isopycnal advection of large scale PV and temperature.
A review of the potential of nature-based solutions (NBS) to address the challenges of the water-energy-food nexus (WEF Nexus) in the coming decades
Authors: Carvalho Pedro N , Finger David , Masi Fabio , Cipolletta Giulia , Oral Hasan Volkan , Tóth Attila , Regelsberger Martin , Exposito Alfonso
Published: March 2021

The water, energy, and food security nexus (WEF Nexus) is the interlinkage between water security, energy security, and food security. An increasing world population is projected to increase energy and food requirements, which will increase the need for freshwater drastically in the coming decades. Projected climate change impacts will aggravate water availability, especially in urban areas. Nature-based solutions (NBS) have proven to generate multiple benefits that defuse the expected merging tensions within the WEF Nexus. This paper outlines the theories, provides examples, and discusses the potential of NBS to address the future WEF Nexus. For this purpose we reviewed recent papers on the theories of WE, WF, EF, and WEF Nexus, we described and summarized 19 representative real-life case studies, and we identified the knowledge gap within the theory and the case studies. We provide quantitative potentials and qualitative benefits for NBS described in the literature over the past decades. Our review demonstrated the impressive potential of NBS to address the projected challenges within the WEF Nexus. The study concludes by recommending NBS for specific WEF Nexus challenges and highlighting the need for decision-makers to consider the implementation of NBS in urban planings.
mSTAR: Multicriteria Spatio Temporal Altimetry Retracking
Authors: Oettershagen Lutz , Uebbing Bernd , Charfreitag Jonas , Mutzel Petra , Kusche Jürgen
Published: March 2021

Observing coastal sea-level change from satellite altimetry is challenging due to land influence on the estimated sea surface height (SSH), significant wave height (SWH), and backscatter. In recent years specialized algorithms have been developed which allow retrieving meaningful estimates up to the coast. Among these, the Spatio Temporal Altimetry Retracker (STAR) has introduced a novel approach by partitioning the total return signal into individual sub-signals which are then processed leading to a point-cloud of potential estimates for each of the three parameters which tend to cluster around the true values, e.g., the real sea surface. The original STAR algorithm interprets each point-cloud as a weighted directed acyclic graph (DAG). The spatio-temporal ordering of the potential estimates induces a layering, and each layer is fully connected to the next. The weights of the edges are based on a chosen distance measure between the connected vertices. The STAR algorithm selects the final estimates by searching the shortest path through the DAG using forward traversal in topological order. This approach includes the inherent assumption that neighboring SSHs etc. should be similar. However, a drawback of the original STAR approach is that each of the point clouds for the three parameters can only be treated individually since the applied standard shortest path approach can not handle multiple edge weights. Therefore, the output of the STAR algorithm for each parameter does not necessarily correspond to the same sub-signal. To overcome this limitation, we propose to employ a multicriteria approach to find a final estimate that takes the weighting of two or three point-clouds into account resulting in the multicriteria Spatio Temporal Altimetry Retracking (mSTAR) framework. An essential difference between the single and the multicriteria shortest path problems is that there is no single optimal solution in the latter. We call a path Pareto-optimal if there is no other path that is strictly shorter for all criteria. Unfortunately, the number of Pareto-optimal paths can be exponential in the input size, even if the considered graph is a DAG. A simple and common approach to tackle this complexity issue is to use the weighted sum scalarization method, in which the objective functions are weighted and combined to a single objective function, such that a single criteria shortest path algorithm can find a Pareto-optimal path. Varying the weighting, a set of Pareto-optimal solutions can be obtained. However, it is in general not possible to find all Pareto-optimal paths this way. In order to find all Pareto-optimal paths, label-correcting or label-setting algorithms can be used. The mSTAR framework supports both scalarization and labeling techniques as well as exact and approximate algorithms for computing Pareto-optimal paths. This way mSTAR is able to find multicriteria consistent estimates of SSH, SWH, and backscatter.
Content and variability of nutrients in the water area of ​​Blagopoluchiya Bay (Novaya Zemlya, Kara Sea)
Authors: Borisenko Gennadii , Polukhin Alexander , Sergeeva Valentina
Published: March 2021

In the frames of the scientific program “Investigation of the Russian Arctic ecosystems” in 2007-2020 held by Shirshov Institute of Oceanology, comprehensive studies of the bays of the Novaya Zemlya archipelago (NZA) were carried out. There is very little information in the scientific literature on the dynamics and hydrochemical structure of the waters of the bays. Our investigations have revealed that the concentration of nutrients (first of all, nitrates and silicate) in the bays of NZA was higher than in the surrounding water area of ​​the Kara Sea. The most well studied and open for investigations is the Blagopoluchiya Bay in the northern island of NZA. Blagopoluchiya Bay is a fjord-type bay with several streams of the glacier origin.

The concentrations of nutrients (N, P, Si, C) in the streams were observed in August-September (0-1.53 µM of PO43-, 6.4-50.2 µM of SiO32-, 0.6-11.2 µM of NO2-+NO3-, 732-4815 µM of DIC). The observed content of nutrients in the waters of the bay was on average 2 times lower, but not lower than the level limiting the development of phytoplankton.

We suppose that high concentrations of nutrients in NZA bays in August-September were supported by increasing glacial runoff from NZA during the summer open water period and the removal of products of degradation of shore rocks with it. Despite the constant enrichment of nutrients, the concentration of phytoplankton in Blagopoluchiya Bay was extremely low (0.2-0.7 mkgC/l) in comparison with the adjacent marine part of the Kara Sea in all years of research.  Perhaps it was due to osmostress of planktonic algae during desalination of the bay by the NZA runoff.

This work was supported by the State Agreement of The Ministry of Science and Education of Russian Federation (theme №0128-2019-0008); Russian Foundation for Basic Research project 18-05-60069 (processing hydrochemistry data); Russian Scientific Foundation project 19-17-00196 (data obtaining); by the Grant of the President of the Russian Federation MK-860.2020.5 (processing carbonate chemistry data).
Remote sensing of steep-slope volcanoes: the Stromboli case study
Authors: Di Traglia Federico , De Luca Claudio , Fornaciai Alessandro , Manzo Mariarosaria , Nolesini Teresa , Favalli Massimiliano , Lanari Riccardo , Casagli Nicola , Casu Francesco
Published: March 2021

Steep-slope volcanoes are geomorphological systems receptive to both exogenous and endogenous phenomena. Volcanic activity produces debris and lava accumulation, whereas magmatic/tectonic and gravitational processes can have a destructive effect, triggering mass-wasting and erosion.

Optical and radar sensors have often been used to identify areas impacted by eruptive and post-eruptive phenomena, quantify of topographic changes, and/or map ground deformation related to magmatic-tectonic-gravitational processes.

In this work, the slope processes on high-gradient volcano flanks in response to shift in volcanic activity have been identified by means of remote sensing techniques. The Sciara del Fuoco unstable flank of Stromboli volcano (Italy) was studied, having a very large set (2010-2020) of different remote sensing data available.

Data includes LiDAR and tri-stereo PLEIADES-1 DEMs, high-spatial-resolution (HSR) optical imagery (QUICKBIRD and PLEIADES-1), and space-borne and ground-based Synthetic Aperture Radar (SAR) data. Multi-temporal DEMs and HSR optical imagery permits to map areas affected by major lithological and morphological changes, and the volumes of deposited/eroded material. The results lead to the identification of topographical variations and geomorphological processes that occurred in response to the variation in eruptive intensity. The joint exploitation of space-borne and ground-based Differential and Multi Temporal SAR Interferometry (InSAR and MT-InSAR) measurements revealed deformation phenomena affecting the volcano edifice, and in particular the Sciara del Fuoco flank.

The presented results demonstrate the effectiveness of the joint exploitation of multi-temporal DEMs, HSR optical imagery, and InSAR measurements obtained through satellite and terrestrial SAR systems, highlighting their strong complementarity to map and interpret the slope phenomena in volcanic areas.

This work was financially supported by the “Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile” (Presidency of the Council of Ministers – Department of Civil Protection); this publication, however, does not reflect the position and official policies of the Department".
New age constraints on the Ouarzazate Group (Morocco): implications on the hypothesis of True Polar Wander during the Ediacaran
Authors: Robert Boris , Corfu Fernando , Blein Olivier
Published: March 2021

The Ediacaran (635-541 Ma) is the last geological period of the Precambrian during which major changes occurred in the superficial layers of the Earth (biosphere, cryosphere, oceans, atmosphere). The paleomagnetic data from the main continents of this epoch display very fast polar wander excursions, which seemed to occur simultaneously on several continents. Two main competing hypotheses have been proposed in the literature to explain these data: (1) very fast True Polar Wander episodes (TPW), which represent the global movement of the mantle and the crust with respect to the Earth's spin axis, or (2) perturbations of the Earth’s magnetic field. On geological timescales, the TPW is speed-limited to some degrees per million years while magnetic field changes could be much faster (degrees per kyrs). The velocity of the polar wander excursions of the Ediacaran is therefore a critical parameter to distinguish these two families of solutions. The volcanic rocks of the Ouarzazate group (575-545 Ma) in the Anti-Atlas belt recorded a large polar wander excursion from ~571 to ~565 Ma, which is also observed in Laurentia and Baltica at about the same time. Because the age uncertainties are too high, the existing SHRIMP U-Pb ages obtained on zircons are not precise enough to distinguish these two hypotheses. In this study, we bring new high-precision CA ID-TIMS ages on zircons from seven tuff layers that recorded the rapid paleomagnetic variations. Our results show, in most of the samples, a large spread in age, indicating either the presence of inherited zircons or strong Pb loss in some of the zircons. Four of the samples display a good consistency in the zircon ages, and could represent the age of the tuff emplacement. In this presentation, we will discuss the two hypotheses based on these new geochronological constraints.
On the dependency of jumps on particle shape in bedload transport of monodisperse non-spherical particles
Authors: Jain Ramandeep , Rebel Ricardo , Fröhlich Jochen
Published: March 2021

Accurate prediction of sediment transport is highly desirable because of its key importance in many environmental and industrial applications. One way to approach this is to measure the length and height of the jump of a moving particle. This led to many studies dealing with the quantification of a particle jump. Nevertheless, few experiments have been performed to understand the effect of particle shape on its jump. A dataset of jumps of differently shaped particles has been generated by the authors from direct numerical simulations of bedload transport in a turbulent open channel flow. A total of four simulations were performed with a large number of mobile single shaped, mono-disperse particles. Four ellipsoidal shapes were used in these simulations, i.e. oblate, prolate, sphere, and a generally shaped ellipsoid. In the present contribution, statistical properties of the jump trajectories such as ejection and landing angles, flight length, height, and time, etc. will be reported. Mean jump trajectories for different particle shapes were calculated using the Dynamic-Time-Warping algorithm. The analysis provides a quantification of the different behavior of the particles under the present conditions. For example, it is observed that oblate particles travel a maximum distance in a jump, while spherical particles take small jumps but more often.
Strong B-Field Fluctuations Caused by the Electromagnetic LHDI and their Impact on 3D Reconnection
Authors: Allmann-Rahn Florian , Lautenbach Simon , Sydora Richard , Grauer Rainer
Published: March 2021

The electromagnetic branch of the lower-hybrid drift instability (LHDI) can lead to kinking of current sheets and fluctuations in the magnetic field and is present for example in Earth’s magnetosphere. Previous particle-in-cell studies suggested that the electromagnetic LHDI’s saturation is at a moderate level and that strong current sheet kinking is only caused by slower kink-type modes. Here, we present kinetic continuum simulations that show strong kinking and high saturation levels of the B-field fluctuations. Has the impact of the electromagnetic LHDI been underestimated? The capability of the LHDI to produce x-lines and turbulence in 3D reconnection is discussed at the example of ten-moment multi-fluid simulations.
Microplastics occurrence in an urban space - Coimbra city case-study
Authors: Amorim Leitão Inês , van Schaik Loes , Dinis Ferreira António , Geissen Violette
Published: March 2021

The progressive increase of population living in cities led to the aggravation of the pollution problem worldwide, especially in urban environments. Air, water and soil are compartments affected by this reality, and the pollution leads to human health problems. There are many different point and non-point sources of emerging pollutants such as microplastics, which are transported diffusely through wind and rain. Therefore, it is very complex to quantify, control and treat these pollutants, designated current problematic issues by the European Commission. Green areas are pointed out by experts as natural filters for contaminants in cities, through their capacity of retention by leaves and soil.

This study investigates the contamination of microplastics in urban green areas soils, as well as the possible sources of microplastics, with a case-study in Coimbra (Portugal). Nine samples of fifty grams of soil were taken: three from a mixed broad-leaved with coniferous forest; three from a green park; three from a natural grassland. Six samples of three litres of water were taken from: rainwater (wet and dry deposition); runoff; freshwater; stream near the mixed forest; stream near the green park; stream near the natural grassland. All the samples were analysed in the laboratory through the extraction of microplastics using the flotation and filtration methods, and the visualization and identification of the particles with a microscope.

Microplastic particles were found in all samples. The number of microplastics found in soil samples varies between 2200 p kg-1 and 190400 p kg-1, both values obtained in a green urban park. Different levels of microplastics were found in the soil of the three sampled spaces with just a few meters of distance. Most of the particles (80%-98%) have less than half a millimetre. The water samples contained a lower number of microplastic particles. The values ranged from 27 p l-1 in a peak flow stream near the natural grassland and 7 p l-1 in freshwater from the tap. In rainwater were found 15 p l-1 and in runoff 17 p l-1 particles. Almost all microplastics particles (97%-100%) from water have less than half a millimetre.

Characteristics such as leaf area index, road proximity and intense precipitation episodes could influence the quantity of microplastics in the soil of green areas and in the streams and runoff. In order to control the entry and the concentration of microplastics in the environment and treat polluted areas, especially in cities, it is essential to quantify the microplastics particles considering the sources, pathways and the local characteristics of vegetation and soils.
Influence of nitrification inhibitor (Nitrapyrin) on winter wheat yield 
Authors: Mirkhani Rayehe , Ghavami Mohammad Sajad , Ahmadi Elnaz , Moghiseh Ebrahim
Published: March 2021

Nitrogen (N) is a crop nutrient that is commonly applied as fertilizer, however the dynamic nature of N and its propensity for loss from soil‐plant systems creates a unique and challenging environment for its efficient management. Nitrification inhibitors (NIs) are compounds that can reduce the bacterial oxidation of NH4+ to NO2− by inhibiting the activity of ammonia-oxidizing bacteria and maintaining a higher proportion of applied nitrogen in the soil by preventing nitrate loss from leaching and gaseous N losses from nitrification and denitrification. The organic compound 2-chloro-6-(tri-chloromethyl) pyridine, commonly known as nitrapyrin (NP), is such a nitrification inhibitor that is used in agriculture. The objective of this study was to investigate the effect of NI (NP) on winter wheat yield compared to farmers practice without NI at a given N rate and same number of N split applications.

A randomized complete block design in five replications was used in this study. Treatments were: T1 (control treatment - without urea), T2 (farmers practice - 300 kg urea/ha), and T3 (urea+NP - 300 kg urea/ha). Urea was applied in three split applications at tillering, stem elongation and booting stages in treatments T2 (farmers practice) and T3 (urea+NP). The average grain yield of winter wheat was 8.7 t ha-1 for the farmers practice (T2) and 9.1 t ha-1 for the urea+NP treatment (T3) at the same number of split fertilizer applications.

The crop yield data showed that urea applied with NP (T3) did increase only slightly grain yield, as compared to farmers practice (T2). The grain yield increase with NP was about 4%, however the statistical analysis showed that this increase due to the application of urea with NP was not significant. Further research is needed to investigate additional nitrification inhibitors and their effect on wheat production.
Assessing the long-term physical-biogeochemical interactions in the North Indian Ocean using a coupled relocatable model
Authors: Jardine Jenny , Katavouta Anna , Partridge Dale , Polton Jeff , Holt Jason , Wakelin Sarah
Published: March 2021

The Indian Ocean is a dynamic region that is heavily influenced by immense freshwater runoff, extreme meteorological events and the seasonal reversal of monsoonal currents. Providing essential resources for over one-third of the global population, the Northern Indian Ocean is a key area of research: increased freshwater run-off, low overturning velocities and high air-sea fluxes result in the region being highly susceptible to climate fluctuations, and execess nutrients, particularly nitrates accumulated through agricultural run-off, directly influence marine biogeochemical cycles. The South Asia Nitrogen Hub (SANH) is a GCRF project designed to assess, monitor and predict the physical and biogeochemical response of the Northern Indian Ocean to such anthropogenic changes. To address key questions in SANH, a relocatable physical-biogeochemical (NEMO-ERSEM) was configured across the region, which includes the Eastern Arabian Sea and the Bay of Bengal. A 22-year hindcast run (1993-2015) at ~11km resolution allows the physical-biogeochemical processes (including from mesoscale eddies, extreme meteorological events and varying runoff) to be viewed at scale that is otherwise impossible with observational campaigns. In conjunction with the large-scale model domain, 6 smaller high-resolution (~1-2km) coastal models were configurated around the Indian subcontinent, allowing a more focussed view at processes that directly impact coastal populations. Here, we will present initial results from the large-scale hindcast run, the coastal regions, and explore the advantages and caveats of relocatable modelling.
The dynamics of earthquakes rupture : A view from the laboratory
Authors: Passelegue Francois , Paglialunga Federica , Schubnel Alexandre , Di Toro Giulio
Published: March 2021

 

Earthquakes are spectacular natural disasters, with for example the recent disastrous Sumatra and Tohoku-Oki earthquakes (2004 and 2011, respectively). Presently, predicting earthquakes remains one of the biggest societal challenges in natural science. While seismological observations have much improved in recent years, our understanding of earthquake source physics remains limited due to the scarcity of monitored seismic rupture along similar fault systems, making long- or short-time scale predictions impossible. Friction and fracture are the two keys to understanding earthquakes. Laboratory experiments could be a robust solution to study earthquakes under safe and controlled conditions, which is mandatory to understand and compare the details of earthquake source physics. Conversely to common friction experiments conducted at both slow and seismic slip rates, the stick-slip mechanism is associated to the propagation of a rupture front, i.e. the radiation of seismic waves. Using stick-slip as an earthquake analog coupled to a state-of-the-art high frequency acoustic monitoring system, we demonstrated in the past that accelerations recorded in the kilohertz range on centimeter-sized samples were self-similar to the ones one can expect at the kilometric scale for a large earthquake. Based on this laboratory earthquakes catalogue, we highlighted that acoustic and strain measurements can be used to (i) locate and follow seismicity, (ii) estimate the energy budget of laboratory earthquakes, (iii) discriminate the mode of slip and the rupture speed. Lately, using medium scale experiments, we studied the scale dependence of rupture processes. These new results, notably in term of weakening of faulting and energy balance allowed us to initiate a bridge between laboratory earthquakes, fracture mechanics and natural seismicity. We discuss here how these experimental results can be upscaled to natural earthquakes.
Mobile- and Hot Spot Measurement with OPC based Dust Monitor EDM264
Authors: Ziegler Volker , Pesch Markus , Schneider Friedhelm
Published: March 2021

With the EDM264, GRIMM offers a [A1] solution for mobile short- and long-term measurements in outdoor areas and at production sites. For research as well as permanent areal observations on a near reference quality base.

The model EDM264 features a powerful and robust measuring cell based on optical particle counting (OPC) principle with all the advantages that users of GRIMM‘s portable aerosol spectrometers  are used to. The system is embedded in a compact weather-protection housing with all-weather sampling, heated inlet system, data logger and meteorological sensor.

With TSP, PM10, PM4, PM2.5, PM1 and PMcoarse, the EDM264  provides all fine dust fractions real-time, valid for outdoor applications and calculated with the proven GRIMM enviro-algorithm, as well as six additional dust mass fractions pm10, pm2.5, pm1, inhalable, thoracic and respirable for IAQ and workplace measurements.

This highly versatile instrument performs real-time monitoring of particle number, particle size and provides information on particle surface distribution as well as dust mass distribution. GRIMM‘s EDM264 has 31 equidistant size channels, which are PSL traceable.

A high-end data logger enables data acquisition and wireless communication via LTE, WLAN or wired via Ethernet. Backup copies of the measurement data are stored in the device directly.

The rinsing air function, which protects the laser and detector in the optical cell, further increases the reliability and long term stability of the EDM264 under different environmental and climatic conditions.

The entire sample volume flow of 1.2 L/min is analyzed by 100% in the optical cell, which assures excellent counting efficiency at low and high concentrations and complies to the ISO 21501-1standard for OPCs.

With  all  these  features,  the  EDM264 is a world-leading dust monitor for precise monitoring of particulate matter and particle number concentration. This highly reliable instrument is an indispensable tool for many users, who need to measure aerosol levels and air quality outdoors, on construction sites, or at production facilities.

Keywords — aerosol research, aerial observation, fence line monitoring, wild fire detection   
Underestimation of the projected 21st century increase in drought duration, according to emergent constraint: consistent result in CMIP5 and CMIP6 models
Authors: Y. Petrova Irina , G. Miralles Diego , Brient Florent , Donat Markus
Published: March 2021

Droughts are defined as one of the most devastating natural disasters of modern times and a key challenge faced under climate change. The complexity of interacting physical processes that underlie the shortage of rainfall in climate models hampers accurate representation of present-day droughts, and leads to differences in their responses to increased greenhouse gas (GHG) concentrations in the future. As a result, the confidence in drought projections is currently defined as ‘medium to low' by the Intergovernmental Panel on Climate Change (IPCC), and reducing this uncertainty remains one of the main goals in coming years, with significant benefits for human and natural systems. 

In this study we explore a relationship between biases in simulated present-day values of longest annual drought (LAD) and future projections of LAD in an ensemble of CMIP5 and CMIP6 models. We find that present-day model bias explains almost 95 % of the future uncertainty in LAD by the end of the 21st century, attributed to the well-known precipitation simulation errors: “drier” models with longer annual droughts at present tend to predict larger LAD values worldwide in the future, as well as a stronger response to GHG forcing in LAD, which is significant in more than 40 % of the global land area.

Substituting observational LAD estimates from satellite data into this model-revealed “present–future relationlarship” suggests that the 21st century global mean increase in duration of annual meteorological droughts could be significantly larger than predicted by the CMIP5 and CMIP6 model ensembles. This emergent constraint reduces global mean uncertainty range in future LAD estimates from 45–100 to 75–90 days, a level more typical of the prediction range of “drier” models. The findings reveal world regions where climate change may cause stronger meteorological drought aggravation than expected, and emphasise the importance of reducing model errors, which are presently largely owed to rain biases, to increase confidence in future predictions.
Spectral X-ray computed micro tomography: a tool for 3-dimensional chemical imaging
Authors: Sittner Jonathan , Merkulova Margarita , Godinho Jose Ricardo da Assuncao , Renno Axel , Cnudde Veerle , Boone Marijn , De Schryver Thomas , Van Loo Denis , Roine Antti , Liipo Jussi , Guy Bradley Martin , Dewaele Stijn
Published: March 2021

Image-based analytical tools in geosciences are indispensable for the characterization of minerals, but most of them are limited to the surface of a polished plane in a sample and lack 3D information. X-ray micro computed tomography (micro CT) provides the missing 3D information of the microstructures inside samples. However, a major drawback of micro CT in the characterization of minerals is the lack of chemical information that makes mineral classification challenging.

Spectral X-ray micro computed tomography (Sp-CT) is a new and evolving tool in different applications such as medicine, security, material science, and geology. This non-destructive method uses a multi-pixel photon-counting detector (PCD) such as cadmium telluride (CdTe) in combination with a conventional CT scanner (TESCAN CoreTOM) to image a sample and detect its transmitted polychromatic X-ray spectrum. Based on the spectrum, elements in a sample can be identified by an increase in attenuation at specific K-edge energies. Therefore, chemically different particles can be distinguished inside a sample from a single CT scan. The method is able to distinguish elements with K-edges in the range from 25 to 160 keV, which applies to elements with Z > 48 (Sittner et al., 2020).

We present results from various sample materials. Different pure elements and element oxides were measured to compare the position of theoretical and measured K-edge energies. All measured K-edge energies are slightly above the theoretical value, but based on the results a correction algorithm could be developed. Furthermore, different monazite grains were investigated, which can be divided into two groups with respect to the content of different RE elements on the basis of the spectrum: La-Ce-rich and La-Ce-poor. In addition, samples from the Au-U Witwatersrand Supergroup demonstrate the potential applications of Sp-CT for geological samples. We measured different drill core samples from the Kalkoenkrans Reef at the Welkom Gold field. Sp-CT can distinguish gold, uraninite and galena grains based on their K-edge energies in the drill core without preparation.

Sittner, J., Godinho, J. R. A., Renno, A. D., Cnudde, V., Boone, M., De Schryver, T., Van Loo, D., Merkulova, M., Roine, A., & Liipo, J. (2020). Spectral X-ray computed micro tomography: 3-dimensional chemical imaging. X-Ray Spectrometry, September, 1–14.
Tree-ring and 14C dates of moraines of the Greater Azau Glacier (Baksan valley, Northern Caucasus)
Authors: Solomina Olga , Bushueva Irina , Dolgova Ekaterina , Volodicheva Natalya , Alexandrovskiy Alexandr , Zazovskaya Elya
Published: March 2021

The age of moraines of the Greater Azau Glacier was identified by tree-ring analysis of more than 150 Scots pines, by historical and cartographic data, remote sensing, lichenometric and radiocarbon dating. We determined the limits of the area covered by the glacier tongue at the end of the 19th century. We also discuss the controversial issue of the position of the moraine of 1849 CE, which was described by H. Abich [1]. The highest and most clearly shaped lateral moraine, conventionally called the "17th century moraine", was formed earlier than the end of the 16th century (tree-ring minimum age). The oldest tree in the valley (1598 CE) was found at the "forested island" end moraine (2294 m asl). Judging by the size of the lichens Rhizocarpon geographicum (120-130 mm) on this surface the moraine may be several centuries older. We re-examined the trunk of a pine which was discovered in the 1960s buried in the fluvio-glacial sediments presumably formed in 1880s (historical descriptions). It was dated earlier by radiocarbon (140 +/- 75 BP [2] (calibrated date - 1650-1960 CE). According to the ring width cross-dating, the most probable dates of the buried tree are 1759-1883 CE, however, the second likely dates are 1826-1950 CE. Suppressions of pine growth at the forefields of the Greater Azau in the 1640s, 1710s, 1800s, 1840s-1860s CE are synchronous with the advances of the Bosson, Mer de Glace and Grindelwald glaciers in the Alps [2]. Three soil horizons buried in the moraine of the Greater Azau glacier were identified in the artificial outcrop on the left side of the valley (N43.26583, E42.4767, 2370 m asl). The uppermost horizon located 0.6 m below the surface of the moraine is a thin layer of loam developed in a short time interval (130±20 BP (IGAN ams - 6826) 1680-1939cal BP (charcoal). Two lower thicker horizons (buried 13 and 15 m below the surface) indicate longer periods of continuous soil formation lasting for about 720 years (between 774-89 CE and 1496-1641 CE) and for 1750 years (between ca 3 ka BP and 7-8 centuries CE), respectively. They both are well developed soils formed within the loam layers without detrital material, containing a thick dark humus horizon with a high content of soil organic matter, as well as fragments of charcoal and tree bark. During these three periods, the glacier was relatively small.

References

1. Abich H., Geologische Beobachtungen auf Reisen im Kaukasus um Jahre 1873. Moskau, 1875. 138 p.

2. Nussbaumer S., Zumbühl H. The Little Ice Age history of the Glacier des Bossons (Mont Blanc massif, France): A new high-resolution glacier length curve based on historical documents. Climatic Change, 111, 2012. 301-334 pp.
Soil dielectric characterization during freeze–thaw transitions using L-band coaxial and soil moisture probes
Authors: Mavrovic Alex , Pardo Lara Renato , Berg Aaron , Demontoux François , Royer Alain , Roy Alexandre
Published: March 2021

Abstract. Soil microwave permittivity is a crucial parameter in passive microwave retrieval algorithms but remains a challenging variable to measure. To validate and improve satellite microwave data products, precise and reliable estimations of the relative permittivity (εr=ε/ε0=ε′-jε′′; unitless) of soils are required, particularly for frozen soils. In this study, permittivity measurements were acquired using two different instruments: the newly designed open-ended coaxial probe (OECP) and the conventional Stevens HydraProbe. Both instruments were used to characterize the permittivity of soil samples undergoing several freeze–thaw cycles in a laboratory environment. The measurements were compared to soil permittivity models. The OECP measured frozen (εfrozen′=[3.5; 6.0], εfrozen′′=[0.46; 1.2]) and thawed (εthawed′=[6.5; 22.8],
εthawed′′=[1.43; 5.7]) soil microwave permittivity. We also demonstrate that cheaper and widespread soil permittivity probes operating at lower frequencies (i.e., Stevens HydraProbe) can be used to estimate microwave permittivity given proper calibration relative to an L-band (1–2 GHz) probe. This study also highlighted the need to improve dielectric soil models, particularly during freeze–thaw transitions. There are still important discrepancies between in situ and modeled estimates and no current model accounts for the hysteresis effect shown between freezing and thawing processes, which could have a significant impact on freeze–thaw detection from satellites.
Automated detection and analysis of surface calving waves with a
terrestrial radar interferometer at the front of Eqip Sermia,
Greenland
Authors: Wehrlé Adrien , Lüthi Martin P. , Walter Andrea , Jouvet Guillaume , Vieli Andreas
Published: March 2021

Abstract. Glacier calving is a key dynamical process of the Greenland ice sheet and a major driver of its increasing mass loss. Calving waves, generated by the sudden detachment of ice from the glacier terminus, can reach tens of meters of height and provide very valuable insights to quantify calving activity. In this study, we present a new method for the detection of source location, timing and magnitude of calving waves using a terrestrial radar interferometer. This method was applied to 11500 one-minute interval acquisitions from Eqip Sermia, West Greenland, in July 2018. During seven days, more than 2000 calving waves were detected, including waves generated by submarine calving which are difficult to observe with other methods. Quantitative assessment with a Wave Power Index (WPI) yields a higher wave activity (+49 %) and higher temporally cumulated WPI (+34 %) in deep water than under shallow conditions. Subglacial meltwater plumes, occurring 2.3 times more often in the deep sector, increase WPI and the number of waves by a factor 1.8 and 1.3 respectively in the deep and shallow sector. We therefore explain the higher calving activity in the deep sector by a combination of more frequent meltwater plumes and more efficient calving enhancement linked with better connections to warm deep ocean water.
Relative importance of tropopause structure and diabatic heating
for baroclinic instability
Authors: Haualand Kristine Flacké , Spengler Thomas
Published: March 2021

Abstract. Misrepresentations of wind shear and stratification around the tropopause in numerical weather prediction models can lead to errors in potential vorticity gradients with repercussions for Rossby wave propagation and baroclinic instability. Using a diabatic extension of the linear quasi-geostrophic Eady model featuring a tropopause, we investigate the influence of such discrepancies on baroclinic instability by varying tropopause sharpness and altitude as well as wind shear and stratification in the lower stratosphere, which can be associated with model or data assimilation errors or a downward extension of a weakened polar vortex. We find that baroclinic development is less sensitive to tropopause sharpness than to modifications in wind shear and stratification in the lower stratosphere, where the latter are associated with a net change in the vertical integral of the horizontal potential vorticity gradient across the tropopause. To further quantify the relevance of these sensitivities, we compare these findings to the impact of including mid-tropospheric latent heating. For representative modifications of wind shear, stratification, and latent heating intensity, the sensitivity of baroclinic instability to tropopause structure is significantly less than that to latent heating of different intensities. These findings indicate that tropopause sharpness is less important for baroclinic development than previously anticipated and that latent heating and the structure in the lower stratosphere play a more crucial role, with latent heating being the dominant factor.
THE RESEARCH OF THE PARAMETERS OF THE DEVICE FOR CLEANING AND SORTING COTTON SEEDS
Authors: Obidov Avazbek , Hamidov Sardor
Published: March 2021

In this article, a lot of fractional vibrational process of cotton seeds in a carriage with parallel bases
is considered. The lengths of sections and their productivity by seeds are obtained, which significantly affect the
sorting effect.
PENERAPAN STRATEGI SQ4R DALAM MENINGKATKAN KETERAMPILAN MEMBACA PEMAHAMAN
Authors: Zan Apri
Published: March 2021

Reading is one of skills which is crucial to be taught in the Elementary School. SQ4R (survey, question, read, reflect, and review) strategy is one of the alternatives that could be used to improve the students’ reading comprehension. The aim of this research was to describe the implementation of SQ4R strategy in improving the students’ reading comprehension skill in pre-reading, whilst-reading and post-reading in the fifth grade of SD Negeri 51/II Desa Paku Aji Kecamatan Tanah Sepenggal Lintas Kabupaten Bungo. This was a Classroom Action Research. The result of date analysis indicated that the use of SQ4R strategy could improve the students’ reading comprehension skill in pre-reading, whilst-reading and post-reading in the fifth grade of SD Negeri 51/II Desa Paku Aji.
Dannelse til globalt medborgerskap. Solidaritetsarbeid i en barnehagekontekst
Authors: Jermstad Linnéa K. , Kjærgård Per Ivar , Sundnes Hilde
Published: March 2021

I rammeplanen for barnehagen kan vi lese at barn skal få mulighet til å utvikle evnen til å vise solidaritet ved å handle lokalt, nasjonalt og globalt. Tidligere forskning viser at solidaritetsarbeid i barnehager gir positive og negative assosiasjoner. Noen av de negative er at tanken om «vi i vesten» og «de andre» forsterkes, og at «de andre» tolkes som et eksotisk fremmedelement. Denne studien undersøker om solidaritetsarbeid i barnehagen kan være fruktbart i en dannelsesprosess mot globalt medborgerskap der holdninger, menneskerettigheter og verdier står sentralt. Studien ble gjennomført i én utvalgt barnehage på Vestlandet som har lang og omfattende erfaring med solidaritetsarbeid. Det empiriske materialet for studien ble innhentet gjennom kvalitativ metodetriangulering bestående av to semistrukturerte gruppeintervjuer med åtte foresatte, semistrukturert intervju med styrer av barnehagen og en analyse av barnehagens plandokument for solidaritetsprosjektet. Resultatene viser styrker og svakheter ved solidaritetsarbeid i barnehagen, og trekker frem flere elementer som kontinuitet, filosofiske samtaler og en betydningsfull rollefigur som viktige faktorer for at solidaritetsarbeid kan bidra til å danne barn mot globalt medborgerskap.
Film Policies and Film Production in Spain during the Economic Crisis (2007–2017)
Authors: Díaz-González María-Jesús , González-del-Valle Almudena
Published: March 2021

Europe’s leading film-producing countries are France, Germany, Italy, Spain, and the United Kingdom. They were all hit by the global economic crisis, which had a particularly severe impact on Europe in 2010–2012. The consequences of this crisis for film policies and the film industry are understudied. Spain is a unique case for this study because it had to ask the European Union for a financial assistance programme. What changes were made to State film policies as a result of the crisis? How did those changes reflect on the feature film production? This article aims to answer these questions. The method used includes an analysis of film-industry policy documents and official data, and in-depth interviews. The period studied is 2007–2017. The results refer to topics such as State aid for film production; tax incentives; value-added tax (VAT); the obligation to provide advance funding for European audiovisual production, and the number, genre, and mean cost of the feature films produced.
The Relationship between Organizational Ethical Climate and Organizational Trust in Palestinian Ministries: An Empirical Approach
Authors: Jarrar Tariq T. , Ibrahim Hazril Izwar
Published: March 2021

The purpose of this article is to investigate the relationship between organizational ethical climate and organizational trust in Palestinian public ministries by applying the Victor and Cullen’s (1988) framework. For this purpose, the study utilizes a sample of 178 respondents of executive-level employees in which primary data collection is conducted using survey instrument and PLS-SEM for data analysis. The study proposes that a positive relationship between ethical climate types (Caring, Independence, Rules, Law and Codes) and organizational trust, and negative relationship between (Instrumental climate) and organizational trust are all highly important for Palestinian ministries to provide trust and create positive outcome in the workplace.