Volume 44, Nº 10 (2019)
- Ano: 2019
- Artigos: 10
- URL: https://journals.rcsi.science/1068-3739/issue/view/14319
Article
Analysis of the Current State of Lake Baikal Based on Roshydromet Monitoring Data
Resumo
The paper presents the results of the analysis of current changes in the annual, seasonal, and monthly inflow of river water to Lake Baikal. A statistically significant increase in the inflow from November to March due to climate change is revealed. The dependence of the annual water level rise in the lake on the inflow is investigated. The pollution of the lake is assessed using the hydrochemical and hydrobiological parameters for the areas being under the influence of the most intensive anthropogenic impact. The background pollution in the reserves on the northeastern coast of the lake is also considered.
Peculiarities of Long-term Variability of Surface Water Inflow to Lake Baikal
Resumo
The paper analyzes long-term changes in the water inflow to Lake Baikal which have occurred since the early 20th century and have been transformed due to the global warming intensification since the 1970s. The differences in distribution parameters and in the values of the inflow of estimated probabilities are studied for the full series and for its two parts divided as of1971. The revealed increase in the wintertime inflow is caused by the cold period duration reduction and by the permafrost degradation resulting from the air temperature rise. Since 1996 inflow has decreased, which is associated not only with precipitation reduction but also with evaporation increase. The Selenga River, the largest tributary of Lake Baikal, demonstrates the greatest decrease in runoff among the Baikal rivers.
Water Resources in Mongolia and Their Current State
Resumo
The inland location of Mongolia and its relatively high general elevation above sea level combined with the arid climate favor the formation of the specific hydrological regime of water bodies which are highly vulnerable to climate changes. The formation features and the current state of water resources in Mongolia are considered. A brief description of the main water bodies is given. The available estimates of the impact of anthropogenic factors and climate changes on some components of water balance are discussed.
Evolution of Suspended Sediment Budget in the Deltas of Lake Baikal Tributaries
Resumo
The monitoring, field, and satellite datasets are used to estimate changes in suspended sediment budget for the Selenga and Upper Angara river deltas. Sediment deficit during recent decades dominates delta evolution due to decrease in the sediment delivery to the delta since the middle of the 1970s by 51% for the Selenga River and by 70% for the Upper Angara River. The observed decline in the sediment runoff and peak water flows associated with the sediment deposition within the inundated flood-plain of the deltas leads to the reduction of the sediment aggradation rates over both deltas. Under low water flows we observed longitudinal increase of the sediment transport rates along Selenga River delta; the Upper Angara constantly reduces sediment transport rates under various hydrological conditions.
Estimation of Mineralization Increase in the Under-ice Water Layer of Southern Baikal
Resumo
Changes in the ionic component of the under-ice mineralization in the southern basin of Lake Baikal in 2001–2016 are analyzed. Data on the under-ice layer mineralization variations derived from water conductivity measurements using the SBE-25 high-precision CTD sonde are compared with the results of calculation of salt separation during the formation and growth of the ice cover. The studies demonstrated that the mineralization increase is affected not only by salinization during ice crystallization but also by the water inflow from the central basin of the lake and from the Selenga River (more than a half of its runoff propagates to Southern Baikal in winter).
Ice-thermal Regime of Lake Baikal under Conditions of Modern Warming (1950–2017)
Resumo
The impact of modern climate change on lakes is one of the most relevant problems in the field of limnology. For Lake Baikal this impact is manifested in the change in abiotic characteristics of the lake ecosystem. It is shown that the pattern of modern climate change in the Baikal region includes both the “secular” warming trend and the intrasecular variations which exceed this trend in the scale and may be caused by atmospheric circulation. The effect of atmospheric circulation is associated with the physiographic characteristics of separate parts of the lake and its watershed. The influence of changes in atmospheric circulation on the ice and thermal regime of Lake Baikal is analyzed for the period of 1950–2017 for which objective analysis data on the large-scale atmospheric circulation in the Northern Hemisphere are available.
Ionic Composition of Water in Lake Baikal, Its Tributaries, and the Angara River Source during the Modern Period
Resumo
The results of long-term routine measurements of the concentration of major ions in the water of the Lake Baikal pelagic zone, the Angara River source, and main tributaries of the lake are analyzed. The average values of ion concentration in the water column of the lake and in the Angara River obtained for the recent decade are presented and compared with the data of previous studies. Long-term trends in the concentration of ions in the main Baikal tributaries are shown. Under low-water conditions, the inflow of ions to Lake Baikal through tributaries decreases despite an increase in their concentration in river water. Changes in the chemical composition of water in the tributaries did not affect the ionic composition of water in the Lake Baikal pelagic zone and in the Angara River source.
Atmospheric Circulation Processes and Precipitation Regime in the Northern Part of the Baikal Mountain Region
Resumo
The paper studies the connection between the precipitation regime over the northern Baikal mountain region during the warm season (April–October) and atmospheric macrocirculation processes, the results are presented. Based on the data of ten weather stations, spatiotemporal heterogeneities in the precipitation regime are revealed for the period of 2000–2018. The long-term (since the middle of the 1960s) trends in total precipitation are evaluated. According to the analysis of HYSPLIT five-day backward trajectories (for days with precipitation), the main directions of moisture transport to the study area are identified, and the trajectories are typed for each month. Three groups of atmotpheric macroprocesses which induce precipttation are identified, and the contribution of each group to total precipitation is estimated. The spatial distinction between different parts of the study area in the precipitation regime and predominant moisture sources is found.
Atmospheric Pollution as a Factor of Environmental Hazard in the Baikal Region Cities
Resumo
It is shown that the chronic atmospheric pollution of cities in the Baikal region is caused by the combination of natural and climatic features and the industrial development of the territory. The variations in emissions of pollutants in 2008–2017 indicate an impact of the periods of growth and slowdown of macroeconomic processes in the regions and the transformation of the main production. A dominant role of thermal power engineering and processing industry as well as of road transport in the urban atmospheric pollution in the region is established. A significant increase in average annual concentrations of benzo[a]pyrene is revealed. A stable relationship was found between this growth and the population morbidity (neoplasms, respiratory diseases). The directions for reducing environmental hazards in the Baikal region cities are outlined.
Soil Temperature Dynamics in Transbaikalia under Changing Climate Conditions
Resumo
The dynamics of multiyear mean thermal conditions in the 3.2-m soil layer in Transbaikalia is studied. A high correlation between variations in air temperature and soil temperature is revealed for summer, and low correlation is found for winter. The trends in cumulative soil temperature during the positive and negative temperature seasons are identified. The sum of negative soil temperatures at the depth of 80 cm exhibits an increasing multiyear trend. In cold seasons, the linear trends in soil temperature are stronger as compared to air temperature trends.