Cloud removal methodology from MODIS snow cover product

The Moderate Resolution Imaging Spectroradiometer (MODIS) employed by Terra and Aqua satellites provides spatially snow covered data with 500 m and daily temporal resolution. It delivers public domain data in raster format. The main disadvantage of the MODIS sensor is that it is unable to record observations under cloud covered regions. This is why this study focuses on estimating the pixel cover for cloud covered areas where no information is available. Our step to this product involves employing methodology based on six successive steps that estimate the pixel cover using different temporal and spatial information. The study was carried out for the Kokcha River basin located in northeastern part of Afghanistan. Snow coverage in catchments, like Kokcha, is very important where the melt-water from snow dominates the river discharge in vegetation period for irrigation purposes. Since no snow related observations were available from the region, the performance of the proposed methodology was tested using the cloud generated MODIS snow cover data as possible "ground truth" information. The results show successful performances arising from the methods applied, which resulted in all cloud coverage being removed. A validation was carried out for all subsequent steps, to be outlined below, where each step removes progressively more cloud coverage. Steps 2 to 5 (step 1 was not validated) performed very well with an average accuracy of between 90–96%, when applied one after another for the selected valid days in this study. The sixth step was the least accurate at 78%, but it led to the removal of all remaining cloud cover

Hydrological modelling for meso-scale catchments using globally available data

International audienceThis study focuses on modelling water balances for catchments with limited data availability. The objective was to use globally available data for water balance modelling of meso-scale catchments. The study is carried out in two catchments; one having enough data for the performance check of the model and the other with very few data for model validation. Globally available meteorological and geographical data is used for the basic model inputs. Dissaggregation of the global data, both spatially and temporally, was conducted to distribute the available data across the watershed and to attain higher resolution input data for the model. In addition, a glacier module was developed for the regions covered by glaciers. The HBV-IWS model developed at the Institute of Hydraulic Engineering at the University of Stuttgart is applied. The outcomes of the modelling provide noteworthy results for both catchments that can be used in water resources planning and management issues. Moreover, the research presents the potential for modelling water balances using predominantly globally available data and proposes appropriate disaggregation methods for global data usage

Superhyperfine interactions in Ce3+ doped LiYF4 crystal: ENDOR measurements

The first observation of the resolved Mims electron-nuclear double resonance (ENDOR) spectra from the nearby and remote nuclei of 19F and 7Li nuclei on impurity Ce3+ ions in LiYF4 crystal is reported. It shows that LiYF4:Ce3+ system can be exploited as a convenient matrix for performing spin manipulations and adjusting quantum computation protocols while ENDOR technique could be used for the investigation of electron-nuclear interaction with all the nuclei of the system and exploited for the electron-nuclear spin manipulations.Comment: 4 pages, 2 figures, 1 Table. Reported on Theor-2017 (Kazan, Russia) Conferenc

Multi-operated HIL Test Bench for Testing Underwater Robot’s Buoyancy Variation System

Nowadays underwater gliders have become to play a vital role in ocean exploration and allow to obtain the valuable information about underwater environment. The traditional approach to the development of such vehicles requires a thorough design of each subsystem and conducting a number of expensive full scale tests for validation the accuracy of connections between these subsystems. However, present requirements to cost-effective development of underwater vehicles need the development of a reliable sampling and testing platform that allows the conducting a preliminary design of components and systems (hardware and software) of the vehicle, its simulation and finally testing and verification of missions. This paper describes the development of the HIL test bench for underwater applications. Paper discuses some advantages of HIL methodology provides a brief overview of buoyancy variation systems. In this paper we focused on hydraulic part of the developed test bench and its architecture, environment and tools. Some obtained results of several buoyancy variation systems testing are described in this paper. These results have allowed us to estimate the most efficient design of the buoyancy variation system. The main contribution of this work is to present a powerful tool for engineers to find hidden errors in underwater gliders development process and to improve the integration between glider’s subsystems by gaining insights into their operation and dynamics

Crystal electric field parameters for Yb3+ ion in YbRh2Si2

The tetragonal crystal electric field parameters for Yb3+ ion in YbRh2Si2 are determined from the analysis of the literature data on angle-resolved photoemission, inelastic neutron scattering and electron paramagnetic resonance.Comment: 8 pages, 3 figures, 4 table

Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OX compounds as revealed by rare-earth EPR-probe

X-band electron paramagnetic resonance on doped Er3+ and Yb3+ ions in Y0.99(Yb,Er)0.01Ba2Cu3OX compounds with different oxygen contents in the wide temperature range (4-120)K have been made. In the superconducting species, the strong dependencies of the linewidth and resonance line position from the sweep direction of the applied magnetic field are revealed at the temperatures significantly below TC. The possible origins of the observed hysteresis are analyzed. Applicability of the presented EPR approach to extract information about the dynamics of the flux-line lattice and critical state parameters (critical current density, magnetic penetration depth, and characteristic spatial scale of the inhomogeneity) is discussedComment: 17 pages, 5 Figures. Renewed versio

Evaluate the Interactions between Grassland Ecosystems and Precipitation Anomalies under Changing Grazing Intensity in Central Asia

Long term monitoring of grassland being the largest ecosystem on earth plays an important role in understanding its productivity and transformation (changes) over time. With the availability of remote sensing data, most ecological and environmental problems caused either by human activities such as extensive agriculture, pastoralism which might lead to desertification, land degradation, loss of biodiversity and climate change amongst others can be monitored. For this study, vegetation cover was selected as the main source of examination and subsets of area covered with grasslands were profiled for further monitoring of grassland increasing and decreasing trends in selected areas of Central Asia

The coal seams of the volga-ural region (Russia): Composition, trace elements and conditions of the formation

© SGEM2017. All Rights Reserved. There is a growing interest in the world in coal as critical raw materials. Coal also can be a carrier of many valuable components. An important geological and geochemical task is to find out the conditions for their accumulation in the coal. The complex of trace elements including group of rare earth elements (REEs) has been studied in the coal seams of the Volga-Ural region (Russia). The article is considered the main regularities and reasons of the concentration of trace elements in coal seams. In the Volga-Ural region, economically important coal seams are encountered in the terrigenous Visean Formation (Early Carboniferous). Coal seams lie at the depth about 1 km. The thickness of a major coal seam ranges from 1 to 40 m. The coal has low ash content (around 15 - 26%) and sulfur ranging from 1.49 to 10.22%. The composition of coal ash is dominated by Si (48.9%) and Al (39.7%) oxides. Mineral substance of the coal consists essentially of kaolin, quartz, feldspar, calcite, pyrite, etc. Such minerals as gypsum, muscovite, rutile, magnetite, ilmenite, marcasite, sphalerite, galena, etc are also found in coal. The content of the most of trace elements is usually within average values for coal. High concentrations of Ge (around 20-25 ppm) and Ag (up to 8 ppm) have been discovered in a number of the coal deposits. The coal is characterized by the presence of geochemical anomalies and elevated concentrations of certain trace elements, including REEs. The Volga-Ural coal exhibits a strong enrichment of LREE over HREE (La/Yb ratio is greater than 1). A distinctive feature of the REEs distribution in the coal is anomalous Ce concentrations near the contact with host rocks. The Ce concentration in coal may reach a few tens of ppm. The nature of Ce anomalies in coal can be explained by the change of the pH conditions at a contact between the coal (acidic) and the host rocks (alkaline), by composition of surrounding rocks and the chemical properties of cerium. Under alkaline conditions, trivalent cerium, which is present in carbonate rocks, is oxidized to tetravalent form and easily dissolves in the water. Then, under acidic conditions, tetravalent cerium precipitates within organic matter as a mineral. Mineral and chemical composition of the coal in Volga-Ural region is directly dependent on the paleo-geographic conditions and depositional facies. The composition of the Visean coal is closely related to the composition of the surrounding rocks and the depositional environments during Visean time. The coal-bearing formation has been formed within the local depressions in Tournaisian carbonate deposits along the ancient sea coast in warm and wet climate. The main source of mineral matter and trace elements were weathering rocks around peatlands. Carbonate rocks surround the Visean coal-bearing formation. These rocks are characterized by low content of mafic minerals

Evaluation of Erosion Intensity and Dynamics Using Terrestrial Laser Scanning

© 2018, Pleiades Publishing, Ltd. A new method of instrumental measurement of the intensity of rill and linear erosion on slopes by the method of terrestrial laser scanning is proposed. This method was tested on four plots in 2012–2016 with the use of Trimble™ GX, Trimble™ VX, and Trimble™ TX8 laser scanners. The terrestrial laser scanning is characterized by a high precision and rapidity, which could not be previously achieved by other devices. It has a number of advantages: registration of various types of erosion of temporary water streams; measurements from a distance without the disturbance of the studied surface and providing the safety of works; and calculations of morphometric parameters of slope using a high-precision digital model of topography. The given examples show that this approach may be applied to assess the denudation-accumulative balance of the moved soil material on slopes, to determine the dynamics of amount of deposits on different parts of a slope as a result of different kinds of surface runoff, and to identify spatial regularities of the formation of the network of rills and gullies. In addition, laser scanning makes it possible to perform an integral assessment of the combined impact of the entire combination of exogenous processes developed on slopes and affecting the soil cover. The observations on test plots showed a rather great role of autumn rains in the total soil loss from erosion. The data obtained were used as the basis for the elaboration of practical recommendations concerning the survey organization and monitoring of erosion with the use of laser scanning

Estimates of slope erosion intensity utilizing terrestrial laser scanning

Copyright © 2014 IAHS Press. Despite the large variety of methods for estimating slope erosion intensity, it is still difficult to obtain accurate erosion rates. Therefore, our goal was to develop a method to provide accurate estimates of sheet and rill erosion intensities, and evaluate denudation quantities due to abrasion, landslides and talus processes using a high-precision laser scanning system (Trimble® GX). Differential maps between all stages of surveying and TIN-models were built directly on point clouds in "Trimble® RealWorks" software. Inspection and cross-section tools were used for detailed study of ground movements on the slope surface and the development of linear erosion forms. A new method for accurate estimates of the erosion has been developed using terrestrial laser scanning techniques. It makes it possible to assess the denudation-accumulation balance on erosive slopes, determine the dynamics of the volume of material moved on different parts of the slope in various surface runoff events, and identify spatial regularities forming rill washouts