The Bulletin of Irkutsk State University. Series Earth Sciences最新文献

{"title":"Long-Term Dynamics of Fires in the Southern Steppes of the Northern Caspian and Mugodzhar","authors":"V. M. Pavleichik, Z. Sivohip","doi":"10.26516/2073-3402.2023.44.88","DOIUrl":"https://doi.org/10.26516/2073-3402.2023.44.88","url":null,"abstract":"The purpose of the study is to identify regional features of the formation and long-term dynamics of grass fires in the southern steppes. A vast expanse covering mainly the southern steppe landscapes of the small-scale Mugodzhara massif, the plains of the Northern Caspian and Turgai is accepted as the key territory. The presented results are based on the analysis of the formed database of geospatial data containing information about the time and spread of fires for 1986-2021. The source materials were satellite images of Landsat and MODIS (Terra and Aqua satellites). As an indirect indicator of the pyrological state of the steppes, long–term statistical data on the number of grazed cattle (cattle, sheep and goats, horses). A significant heterogeneity of the pyrologic conditions for the years under review was revealed, three phases were identified: low (1986–2000), high (2001– 2010) and medium (2011–2021) fire activity. A comparison of the data obtained with the results of similar studies conducted by the authors earlier on the northern steppes indicates a high degree of similarity in the long-term dynamics of wildfires. By identifying the closeness of connections, it was established that the observed changes in the nature of fire–hazardous situations are due to changes in the intensity of use of plant and land resources, mainly during the agricultural development of the region. The intensification of fires was the result of the spontaneous restoration of steppe vegetation on uncultivated arable and little-used pasture lands associated with a sharp reduction in the level of agricultural production in the countries of the former USSR. It took about 8 years to restore the previously degraded vegetation to a state capable of supporting the steady spread of fires. One of the factors of pyrogenicity is the floral composition of plant communities and the density of herbage. The deterioration of the pyrological situation in the southern steppes (as well as in other steppe subzones) has become a specific regional response to the changed conditions.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134507819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transformation and Reconstitution of Vegetation in the Pre-Baikal","authors":"A. Sizykh, B. Ras","doi":"10.26516/2073-3402.2021.37.86","DOIUrl":"https://doi.org/10.26516/2073-3402.2021.37.86","url":null,"abstract":"The work represents the results of perennial studies of the structural-dynamic organization of the phytocoenoses, which are subjected during a long period to anthropogenic impact in different, for geographical conditions, areas of western and south-eastern Pre-Baikal. The composition of phytocoenoses, which form at cuttings of forests of different composition and typology is found out. The following parameters are determined: species composition, synfolial differentiation and dominant species of the soil cover reflecting the dynamics of reconstitutional stages of polydominant light-coniferous forests of Pre-Baikalian type. We noticed the peculiarities of transformation and reconstitution of the coenoses, which during a long period are used for haying and pasturage formed on the site of earlier cut timber stands at the boundary with the extrazonal steppe. During last decades, a gradual forestation of these territories is observed, the steppe plants species in the soil cover are replaced by forest species characteristic for the light-coniferous taiga. On the site of cuttings of dark-coniferous taiga in the first half of the last century in the southern part of Pre-Baikal, forests form with dominance of more hydrophilic trees species in undergrowth and young growth – fir and spruce replace cedar everywhere. This is probably due to secular forests dynamics with replacement of forest forming trees species on the background of climate changes during last decades. There are as well changes in the species composition of plants on the soil cover of forming dark-coniferous taiga.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131695373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Landscapes of the Buffer Zone of the Baikal Natural Territory","authors":"T. Konovalova","doi":"10.26516/2073-3402.2022.40.58","DOIUrl":"https://doi.org/10.26516/2073-3402.2022.40.58","url":null,"abstract":"The article discusses the natural features of the buffer ecological zone of the Baikal natural territory. They are associated with the impact of the Baikal rift zone and the Angara-Vitim granitoid batholith. It is established that the research area is characterized by significant contrasts of land- scapes, which are confined to various tectonic structures. It was revealed that in the areas of the impact of large active faults, along which the influx of endogenous heat is recorded, the landscapes of the Middle Siberian, Central Asian and Amur-Sakhalin physico-geographical regions have developed. The Siberian cedar was found to be confined to the areas of development of acidic granites. It is established that the spatial differentiation of the landscapes of the research area is determined not so much by latitudinal zonality as by the manifestation of tectonic processes and the associated stages of development of the natural environment and landscapes.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129286500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the Dependence of the Area and Volume of Posolsky Bay from the Level of Lake Baikal","authors":"E. Boldanova","doi":"10.26516/2073-3402.2023.44.33","DOIUrl":"https://doi.org/10.26516/2073-3402.2023.44.33","url":null,"abstract":"The article is devoted to the issues of regulating the level of Lake Baikal and assessing its consequences. Posolsky and Maly bays of Lake Baikal are of great fishery importance. It is here that the larvae of the omul of Posolsky population feed themselves. The survival of juveniles depends on fluctuations in the areas and volumes of these reservoirs. The purpose of this study is to determine the dependence of the areas and water bodies of the Posolsky and Maly bays on the level of Lake Baikal. To achieve this goal, the tasks of choosing indices for determining the coastline from Sentinel-2 satellite images, processing the initial data, calculating the areas of reservoirs at different levels of Baikal, estimating the model parameters and using it to build a digital elevation model (DEM) were set and solved. A number of indices for determining the boundaries of a reservoir are considered, and the NDWI index is chosen based on the overall accuracy and Cohen's kappa coefficient. With the help of the DEM, the volumes of reservoirs were determined. The obtained dependencies allowed us to conclude that at the level of the lake. Baikal, within the limits of 456.2-456.8 m of the Pacific height system, slight changes in areas and volumes are observed, which can be considered safe for the survival of omul juveniles. The most critical changes occur when the lake level drops below 456.0 m and exceeds 457.0 m. The results obtained will make it possible to make more informed decisions on lake level regulation.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128540872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment Load Runoff of Lake Baikal Tributaries: Changes and Trends","authors":"T. Potemkina, V. Potemkin","doi":"10.26516/2073-3402.2023.43.79","DOIUrl":"https://doi.org/10.26516/2073-3402.2023.43.79","url":null,"abstract":"t. Since the second half of the 1970s, rivers flowing into Lake Baikal have been experiencing a tendency to the sediment load reduce against the background of the global warming and various human activity in river basins. Integrated analysis of changes in hydro-meteorological parameters) and their trends over the period 1941–1975 (baseline) and 1976–2020 (warming) is performed. Changes in natural processes and human activity were negligible during the baseline period. In 1976–2020, the flow of sediment load in tributaries decreased by 53–80 % and changes occurred in its regime, which manifested itself in a decrease in its average and maximum indicators. The largest decrease in sediment load runoff was established in the last decades of the warming period. The average values of runoff in these decades are lower than the average value for the entire observation period by 1,5–3 times and by 3-5 times in comparison with the baseline period. Sediment runoff in the last decades corresponds to their modern export from tributaries to Lake Baikal and is 713∙103 t y−1 for Selenga, 85∙103 t y−1 for Upper Angara, 44∙103 t y−1 for Barguzin, 9,4∙103 t y−1 for Utulik and 7,9∙103 t y−1 for Hara-Murin. The results of the research are important for the study of processes related to lithodynamics, sedimentology, biogeochemistry, ecology in the system “Rivers – Lake Baikal” and contributes to the protection and rational management of the water resources of the lake.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"185 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128640548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water Discharge Measurement by ADCP During Freeze-up Period","authors":"S. V. Buzmakov, A. V. Iukhno, A. A. Zorina","doi":"10.26516/2073-3402.2022.39.28","DOIUrl":"https://doi.org/10.26516/2073-3402.2022.39.28","url":null,"abstract":"As a part of the modernization of the national hydrological network, a large number of ADCPs were delivered to the stream-gaging stations of the Roshydromet and, as a rule, used only during the open channel period. At the same time, the measurement of water discharge during the freeze-up period has always been a laborious, technically complex task, and using ADCPs during this period can optimize the measurement procedure. The article presents the issues of the features of ADCPs using on the national hydrological network of Roshydromet, the existing instrument and methodological base for measuring water discharge under the ice cover with ADCP. Either, the results of comparative field measurements of water discharge and velocities on the Ob, Neva and Oredezh rivers were considered. These rivers cover a wide range of hydrodynamic conditions: the Ob is a typical large river, with an average flow velocity is about 0.30 m/s, and a maximum depth about 20 m; the Neva is a unique large river, with a high average flow velocity value is about 0.8 m/s and a maximum depth not exceeding 11 m; the Oredezh river is a typical small river with mean flow velocity about 0.2 m/s and depths of not more than 1.5 m. In the experiments, ADCP Teledyne RiverRay and SonTek M9 were used, and comparative measurements were performed by the mechanical current meter and electromagnetic flow velocity device “Poseidon-1”. On the basis of these experiments first conclusions were drawn about the features of the ADCP application during the freeze-up period. Thus, the authors found that it is most effective to use ADCPs on medium and large rivers - labor and time costs are significantly lower than using conventional methods for measuring water flow, and the measurement accuracy is comparable. At the same time, the article notes a number of significant weak points, most of which boil down to the thesis that the measurement of water discharges using ADCP under ice involves the use of a large number of technically complex and expensive equipment, and the failure of at least one element leads to the inability to complete the measurement. Special attention is paid to the main technical aspects of working with devices, as well as with specialized software. Therefore, it is always recommended to have a spare standard measuring instrument in extra. The main technical aspects of working with devices as well as with specialized software are also discussed in more detail in the body of the article.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123621909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Glacier Dynamics in the Himalayas and Mountains of the Southern Eastern Siberia","authors":"A. Kitov, V. Pluysnin","doi":"10.26516/2073-3402.2019.29.68","DOIUrl":"https://doi.org/10.26516/2073-3402.2019.29.68","url":null,"abstract":"","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122721507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Comfort Development Potential in Urbanized Geosystems of Volgograd and Orenburg","authors":"S. Dubrovskaya, R. Ryakhov, V. M. Pavleychik","doi":"10.26516/2073-3402.2022.42.29","DOIUrl":"https://doi.org/10.26516/2073-3402.2022.42.29","url":null,"abstract":"The article presents the results of assessing the comfort potential and development prospects of the urbanized geosystems of Volgograd and Orenburg on the basis of the developed geoinformation index of the urban environment comfort development potential (City Development Potential Index, CDPI). To ensure a comfortable and sustainable living environment in cities, it is necessary to carry out an active environmental impact to reduce the anthropogenic load. Urban green spaces are an important component for improving the well-being and health of citizens. An index was calculated based on indicators of the total area of technical geosystems of the territory, consisting of the sum of the areas of individual functional zones and the ratio of existing and projected natural-anthropogenic components to areas suitable for expanding green areas. Cartographic models have been constructed that reflect the differentiation of urban landscapes. Areas with negative index values have been identified where it is impossible (or minimally possible) to plant greenery on the territory due to the high density of existing anthropogenic geosystems. Low positive index values (from 0 to 0.5) refer to trees and shrubs relatively suitable for planting. The closer the positive value of the indicator to 1, the higher the potential for the development of recreational areas and the lower the existing anthropogenic load of the totality of technogenic subsystems. Calculations of index values for the studied cities showed significant differences related to the features of the planning structure, spatiotemporal development of infrastructure and the relief component of the landscape. The city of Volgograd is characterized by predominantly negative and low positive values of the index. Index values for determining the potential for the development of comfort in the city of Orenburg are much higher.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129778833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Variability of the Concentration of Chloride Ions in the Water of the Kuibyshevsk Reservoir","authors":"K. Selezneva, A. Selezneva, V. A. Seleznev","doi":"10.26516/2073-3402.2022.40.105","DOIUrl":"https://doi.org/10.26516/2073-3402.2022.40.105","url":null,"abstract":"According to long-term observations in the period 2001–2019. regularities of seasonal variability of the content of chlorides in the water of the Kuibyshev reservoir were studied. Stationary hydrochemical observation point is located in the outlet section of the reservoir. To study the causes of seasonal variability in chloride concentrations, hydrological data were used at the inlet (Cheboksary and Nizhnikamsk waterworks) and outgoing (Zhigulevsk waterworks) sections of the Kuibyshev reservoir. It was found that over the 19-year observation period, the range of seasonal fluctuations in average monthly chloride concentrations was 14–42 mgdm3. Seasonal variability of chloride content is pronounced and is characterized by alternating maxima and minima of chloride concentration. The winter maximum is observed in April before the beginning of the spring flood, and the summer maximum is observed in July before the beginning of the autumn low water. The spring minimum is observed in May at the peak of the spring flood, and the autumn minimum is observed in December before the freeze-up begins. The seasonal variability of chlorides includes four periods (I, II, III, IV), which are formed as a result of the interaction of genetically heterogeneous water masses in the reservoir. Period I is characterized by a gradual increase in the concentration of chlorides due to the inflow of groundwater during the winter low water. The short-term period II is characterized by a sharp decrease in the concentration of chlorides due to the entry of soil-surface waters into the reservoir during the spring flood. Period III is characterized by an increase in the concentration of chlorides due to an increase in the role of soil and groundwater during the summer low water period. Period IV is the longest and is characterized by a gradual decrease in the concentration of chlorides during the autumn low water period. The revealed patterns of seasonal variability of chlorides are unchanged and were observed annually during 2001–2019. However, the values of chloride concentrations significantly depended on the hydrometeorological conditions of a particular year. In dry years, the concentration of chlorides increased, and in high-water years, they decreased in all hydrological seasons of the year.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134048457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical Composition of the Snow Cover and Meltwater of the Garmo Glacier Components of the Hydrochemistry of the Obikhingou River in the Vakhsh River Basin","authors":"I. Normatov, N. S. Sheralizoda, A. Homidov, F. A. Sharofzoda, A. Muminov","doi":"10.26516/2073-3402.2022.42.58","DOIUrl":"https://doi.org/10.26516/2073-3402.2022.42.58","url":null,"abstract":"t. The aim of the work is to study the chemical composition of snow cover and meltwater from the Garmo glacier and their contribution to the formation of the hydrochemistry of the Obikhingou river. The results of monitoring the meteorological conditions of the Obikhingou river basin and hydrology for the period 1960-2020 are presented. According to the estimates, the rate of increase in the average annual temperature values for the period 1960-2020 in the Vakhsh river basin as a whole flows differently and is in the basins of its tributaries: Surkhob 6.3∙10-3 оC/yr, Kyzylsu 13.5∙10-3 oC/yr and Obikhingou 18.6∙10-3 oC/yr. The temperature increases on the Vakhsh River upstream by 2050 is expected 0.4-0.7 o C compared to the period 1960-2020. For the period 1960-2020 there was a slight increase amount of atmospheric precipitation in the Obikhingou river basin with an average annual value of 3.7 mm/yr. By determining the concentration of chemical elements on the Obikhingou river downstream, the values of indicators (SAR, %Na+, SSP and ESP) of the applicability of river water for irrigation were calculated that were significantly lower than their critical values.","PeriodicalId":147615,"journal":{"name":"The Bulletin of Irkutsk State University. Series Earth Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132196376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}