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Paleoclimate Study of Mountain Ecosystems by Multiple Group Biological Analysis

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Journal of Mountain Science 2011年第1期8卷 24-36页

作者： Marina SKRYPNIKOVA olga USPENSKAYA olga KHOKHLOVA Dokuchaev Soil Science Institute of Russian Academy of Agricultural Sciences Pyzhevsky Lane7Moscow109017Russia Vegetable Institute of Russian Academy of Agricultural Sciences h.500v.VereaRamenskii distMoscow region140153Russia Institute of Physical Chemical and Biological Problems in Soil Science of RASUlitsa Institutskaya2PushchinoMoscow region142290Russia

Methodological problems of climatic reconstruction for different periods of Holocene are discussed on the basis of a multiple group biological analysis on peat-sapropel sediments. The possibility of biological analysis is exemplified by the paleoclimatic reconstruction for Carpathian and Altai Mountain ranges. For the ＂Skolevsky Beskidy＂ national park of Carpaty the paleoclimatic scenarios have been drown up aiming at the more precise definition of climatic conditions for the period of mass mountain slope terracing. The stability of terrace systems of various designs in the current climatic conditions has been assessed. It is shown that during periods of humid climate the terraces, whose designs have been focused on drainage, were built. In periods of dry and warm climate the terrace systems capable of accumulating water were built. Both these types of terrace systems are destroyed in nowadays. Only those terrace systems are stable which were adjusted by their builders to contrast variations of precipitation. For Western Altais the paleoclimatic scenario has been done to forecast the safety of the Bronze Age kurgans （burial earth mounds） with permafrost inside the construction. In the Altay region during the Holocene it has revealed two periods of sharp cooling, the peaks of which occurred in the intervals 4500- 4300 and 2500-2300 years pronounced climatic drying ago, and two periods of 4900-4700 and 130-70 years ago. Depletion of the algae composition in the layer corresponding to the last period of drying climate indicates a very sharp change in the parameters of moisture and turning the lake into a dry swamp. Periods of cold weather may have contributed to the formation of special ritual traditions of the Sakan tribes that require the frozen ground to bury the dead. The later climate fluctuations identified have not affected the safety of permafrost in burial mounds constructed in the V-III cc BC.

关键词： Climatic reconstruction Complex group biological analysis of peat-sapropel sediments Paleopedology Soil evolution Holocene

INITIAL VALUE TECHNIQUES FOR THE HELMHOLTZ AND MAXWELL EQUATIONS

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Journal of Computational Mathematics 2007年第3期25卷 368-373页

作者： Frank Natterer olga Klyubina Department of Mathematics University of MünsterGermany

We study the initial value problem of the Helmholtz equation with spatially variable wave number. We show that it can be stabilized by suppressing the evanescent waves. The stabilized Helmholtz equation can be solved numerically by a marching scheme combined with FFT. The resulting algorithm has complexity n^2 log n on a n x n grid. We demonstrate the efficacy of the method by numerical examples with caustics. For the Maxwell equation the same treatment is possible after reducing it to a second order system. We show how the method can be used for inverse problems arising in acoustic tomography and microwave imaging.

关键词： Stability of elliptic initial value problems Parabolic wave equation Inverseproblems in acoustics and electromagnetics.

Longitudinal dependence of the forecast accuracy of the ionospheric total electron content in the equatorial zone

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Geodesy and Geodynamics 2024年第5期15卷 528-541页

作者： Artem Kharakhashyan olga Maltseva Institute for Physics Southern Federal University344090Russia

The longitudinal dependence of the behavior of ionospheric parameters has been the subject of a number of works where significant variations are *** also applies to the prediction of the ionospheric total electron content(TEC),which neural network methods have recently been widely ***,the results are mainly presented for a limited set of *** paper examines the longitudinal dependence of the TEC forecast accuracy in the equatorial *** this case,the methods are used that provided the best accuracy on three meridians:European(30°E),Southeastern(110°E)and American(75°W).Results for the stations considered are analyzed as a function of longitude using the Jet Propulsion Laboratory Global Ionosphere Map(JPL GIM)for *** results are for 2 h ahead and 24 h ahead *** was found that in this case,based on the metric values,three groups of architectures can be *** first group included long short-term memory(LSTM),gated recurrent unit(GRU),and temporal convolutional networks(TCN)models as a part of unidirectional deep learning models;the second group is based on the recurrent models from the first group,which were supplemented with a bidirectional algorithm,increasing the TEC forecasting accuracy by 2-3 *** third group,which includes the bidirectional TCN architecture(BiTCN),provided the highest *** this architecture,according to data obtained for 9 equatorial stations,practical independence of the TEC prediction accuracy from longitude was observed under the following metrics(Mean Absolute Error MAE,Root Mean Square Error RMSE,Mean Absolute Percentage Error MAPE):MAE(2 h)is 0.2 TECU approximately;MAE(24 h)is 0.4 TECU approximately;RMSE(2 h)is less than 0.5 TECU except Niue station(RMSE(2 h)is 1 TECU approximately);RMSE(24 h)is in the range of 1.0-1.7 TECU;MAPE(2 h)24 h)2%.This result was confirmed by data from additional 5 stations that formed latitudinal chains in the

关键词： Ionosphere Total electron content Forecasting BiGRU BiLSTM BiTCN Temporal convolution

Paleoproterozoic,High-Metamorphic,Metasedimentary Units of Siberian Craton

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Acta Geologica Sinica(English Edition) 2009年第5期83卷 875-883页

作者： Lena URMANTSEVA olga TURKINA Institute of Geology and Mineralogy Siberian BranchRussian Academy of SciencesNovosibirskRussia

Sensitive, high-resolution ion microprobe zircon U-Pb ages of Paleoproterozoic, high-grade, metasedimentary rocks from the south-western part of the Siberian Craton are reported. Early Precambrian, high-grade complexes, including garnet-biotite, hypersthene-biotite, and cordierite- bearing gneisses compose the Irkut terrane of the Sharyzhalgay Uplift. Protoliths of studied gneisses correspond to terrigenous sediments, ranging from greywacke to shale. The paragneiss model Nd ages of 2.4-3.1 Ga indicate Archean-to-Paleoproterozoic source provinces. Zircons from gneisses show corerim textures in cathodoluminescence （CL） image. Round or irregular shaped cores indicate detrital origin. Structureless rims with low Th/U are metamorphic in origin. The three age groups of detrital cores are：〉2.7, -2.3, and 1.95-2 Ga. The ages of metamorphic rims range from 1.86 to 1.85 Ga; therefore, the sediments were deposited between 1.95 and 1.86 Ga and derived from Archean and Paleoproterozoic source rocks. It should be noted that Paleoproterozoic metasedimentary rocks of the Irkut Block are not unique. High-grade metaterrigenous sediments, with model Nd ages ranging from 2.3 to 2.5 Ga, are widely distributed within the Aldan and Anabar Shields of the Siberian Craton. The same situation is observed in the North China Craton, where metasedimentary rocks contain detrital igneous zircon grains with ages ranging from 3 to 2.1 Ga （Wan et al., 2006）. All of these sedimentary units were subjected to Late Paleoproterozoic metamorphism. In the Siberian Craton, the Paleoproterozoic sedimentary deposits are possibly marked passive margins of the Early Precambrian crustal blocks, and their high-grade metamorphism was related to the consolidation of the Siberian Craton.

关键词： zircon sensitive high-resolution ion microprobe U-Pb dating metasedimentary rocks,Paleoproterozoic Siberian Craton

Land use in agricultural landscapes with chernozems contaminated after Chernobyl accident: Can we be confident in radioecological safety of plant foodstuff?

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International Soil and Water Conservation Research 2019年第2期7卷 158-166页

作者： olga Komissarova Tatiana Paramonova Radioecology&Ecotoxicology Department Soil Science FacultyLomonosov Moscow State UniversityLeninskie Gory 1-12Moscow 119991Russia

Agricultural land use in the area of the post-Chemobyl Plavsk radioactive hotspot (Tula region,Central Russia) has raised a problem of radioecological safety of obtained plant *** of 137Cs activities and inventories in components of 'soil-plant' systems of the territory has been conducted in 2014-2017 in 10 agrosystems and 2 semi-natural *** was revealed that density of 137Cs contamination of arable chernozems and alluvial calcareous soils nowadays varies in a range 140-220 kBq/m2 and exceeds radiation safety standard by^3.5-6 *** plowing of the arable soils up to 30-cm in 1986-1987 resulted in decreasing of 137Cs inventories in rooting zone by ≈ 70% for crops cultivated with shallow disk plowing (wheat,barley),and by ≈ 35% for crops cultivated with middle plowing (buckwheat,amaranth,white mustard).The investigated plants and their compartments can be grouped on the basis of transfer factor values as follows:maize (stems and leaves)> amaranth> bromegrass > vegetation of dry meadow,galega,sunflower (seeds),vegetation of wet meadow > maize (grain),soybean (pods),barley (grain),buckwheat (grain),potatoes (tubers)> white mustard (seeds),wheat (grain).It is noticeable that generative plant compartments are characterized by less 137Cs activities in comparison with stems and leaves;and that 137Cs root uptake is not coincide with total flux of mineral nutrients in 'soil-plant' *** sum,137Cs soil-to-plant transfer in the area of the Plavsk radioactive hotspot is characterized by considerable discrimination,so 137Cs activities in plants are completely in accordance with national standards.

关键词： Radioactive soil contamination Caesium-137 137Cs Arable soils 'Soil-plant' system Chernobyl accident Radioecologically safe land use

Retrieval of Volcanic Sulfate Aerosols Optical Parameters from AHI Radiometer Data

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Advances in Atmospheric Sciences 2024年第10期41卷 1953-1968页

作者： Andrei FILEI olga GIRINA Aleksei SOROKIN Far-Eastern Center of State Research Center for Space Hydrometeorology«Planeta» Khabarovsk 680000Russia Institute of Volcanology and Seismology Far Eastern Branch of the Russian Academy of Sciences Petropavlovsk-Kamchatsky 683006Russia Computing Center of the Far Eastern Branch of the Russian Academy of Sciences Khabarovsk 680000Russia

This paper presents a method for retrieving optical parameters from volcanic sulfate aerosols from the AHI radiometer on board the Himawari-8 *** proposed method is based on optical models for various mixtures of aerosol components from volcanic clouds,including ash particles,ice crystals,water drops,and sulfate aerosol *** application of multi-component optical models of various aerosol compositions allows for the optical thickness and mass loading of sulfate aerosol to be estimated in the sulfuric cloud formed after the Karymsky volcano eruption on 3 November 2021.A comprehensive analysis of the brightness temperatures of the sulfuric cloud in the infrared bands was performed,which revealed that the cloud was composed of a mixture of sulfate aerosol and water *** models of various aerosol compositions allows for the satellite-based estimation of optical parameters not only for sulfate aerosol but also for the whole aerosol mixture.

关键词： H_(2)SO_(4) volcano Himawari-8 mass loading volcanic ash optical thickness the Karymsky volcano

Parabolic Trough Collector and Central Receiver Coupled with Fresnel Lens:Experimental Tests

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International Journal of Automation and computing 2020年第4期17卷 572-587页

作者： Angelica Palacios Dario Amaya olga Ramos Universidad Militar Nueva Granada Bogota 110121Colombia

Renewable energies have a high impact on power energy production and reduction of environmental pollution worldwide,so high efforts have been made to improve renewable technologies and research about *** paper presents the thermal performance results obtained by simulation and experimental tests of a parabolic trough collector with central receiver coupled to Fresnel lens,under different configurations on the *** simulation method was computational fluid dynamics(CFD)analysis in SolidWorks(R)soft-ware tool,which works with Naiver-Stokes equations to converge on a *** tests were formed with all configurations proposed and three observations for each one,a total of 12 observations were performed in all *** a result,the best thermal performance in simulation was achieved with the Fresnel lens and black pipe collector,with a maximum temperature of 116℃under 1000 W/m^2 radiation,the same system achieved in experimental tests a maximum temperature of 96℃with a radiation of 983 W/m^2.

关键词： Solar collector parabolic trough collector Fresnel lens thermal conductivity solar power

Testing of new ionospheric models along the meridian 110°E over the Northern Hemisphere

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Geodesy and Geodynamics 2022年第6期13卷 544-553页

作者： olga Maltseva Artem Kharakhashyan Tatyana Nikitenko Institute for Physics Southern Federal University344090Russia

Despite the continuous improvement of the widely used empirical model international reference ionosphere(IRI),the recently appeared new models must be tested *** along the meridians has the advantage of dealing with the latitudinal dependent *** paper uses new models of parameters foF2(critical frequency),TEC(total electron content),andτ(equivalent slab thickness of the ionosphere),which are of great importance for evaluating the effects of space ***-Plas,NNT2F2,and NTSM models were tested using data from 6 ionosondes located along the meridian 110°E in March *** is shown that the IRI-Plas model provides the closest values to experiment with respect toτ,while the NTSM model provides a rather limited reflection of the latitude *** of foF2(NNT2F2)have shown that,the NNT2F2 model provides good conformity with experimental values in this area,but it is very dependent on the TEC processing *** latitudinal dependences of foF2 obtained with TEC and polynomial dependenceτ(Appr)showed the presence of positive deviations from medians not only during disturbances but also quiet periods,longitudinally at the meridian.

关键词： Ionosphere Modeling Total electron content Critical frequency Meridian 110°E

Territorial Resilience Through Visibility Analysis for Immediate Detection of Wildfires Integrating Fire Susceptibility,Geographical Features,and Optimization Methods

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International Journal of Disaster Risk Science 2022年第4期13卷 621-635页

作者： Stavros Sakellariou George Sfoungaris olga Christopoulou Department of Agriculture Crop Production and Rural Environment University of Thessaly38446 VólosGreece Department of Planning and Regional Development University of Thessaly38334 VólosGreece Computer Science Department University of Crete70013 HeraklionCreteGreece

Climate change effects tend to reinforce the frequency and severity of wildfires worldwide,and early detection of wildfire events is considered of crucial *** primary aim of this study was the spatial optimization of fire resources(that is,watchtowers)considering the interplay of geographical features(that is,simulated burn probability to delimit fire vulnerability;topography effects;and accessibility to candidate watchtower locations)and geo-optimization techniques(exact programming methods)to find both an effective and financially feasible solution in terms of visibility coverage in Chalkidiki Prefecture of northern *** integration of all geographical features through the Analytical Hierarchy Process indicated the most appropriate territory for the installment of *** analysis guaranteed the independence and proximity of location options(applying spatial systematic sampling to avoid first order redundancy)across the *** conjunction of the above processes yielded 654 candidate watchtower positions in 151,890 ha of *** algorithm was designed to maximize the joint visible area and simultaneously minimize the number of candidate locations and overlapping effects(avoiding second order redundancy).The results indicate four differentiated location options in the study area:(1)75locations can cover 90%of the forests(maximum visible area);(2)47 locations can cover 85%of the forests;(3)31locations can cover 80.2%of the forests;and(4)16 locations can cover 70.6%of the *** last option is an e fficient solution because it covers about 71%of the forests with just half the number of watchtowers that would be required for the third option with only about 10%additional forest ***,the final choice of any location scheme is subject to agency priorities and their respective financial flexibility.

关键词： Burn probability Greece Spatial optimization Topography effects Viewshed coverage Watchtowers Wildfire detection