Abstract. The remote sensing methods usage makes it possible to increase the accuracy and efficiency of data on the state of water bodies. Among the many satellite systems, Sentinel-2 is the most suitable for inland water assessment. One of the abiotic factors in assessing the trophicity of water bodies is the transparency along the Secchi disk. Models for calculating water transparency have been developed for individual water bodies. The analysis showed that these models don t adequately describe the transparency for Lake Baikal. Based on the correlation-regression analysis, the parameters of the exponential function were estimated for calculating the transparency of the surface waters of Lake Baikal using the values of the Sentinel-2 spectral channels. Despite the inaccuracy of the model for assessing the transparency in the coastal zone, it can be used to assess the seasonal and interannual transparency of the surface waters of Lake Baikal.

In modern conditions, a constant improvement in the quality of management using new information technologies is required. To monitor water bodies, it is necessary to more widely use geographic information systems with analysis and forecasting capabilities. The main problems in this area are the integration of heterogeneous information about spatially extended water bodies, taking into account the dynamics of changes in time and space, forecasting and presenting the results in a convenient and accessible form for decision-making. To solve these problems, it is proposed to use a systematic approach in the construction of geographic information systems.

The existing models for assessing the trophicity indicators of water bodies are intended for specific water bodies, and adaptation is required for their use with regard to others. Another problem is the lack of approaches in remote monitoring to the development of an integral indicator of the trophicity of water bodies. The purpose of this study is to develop models for calculating biotic and abiotic indicators for assessing the state of a reservoir, as well as an integral indicator of its trophicity. To achieve this goal, the tasks were set to compare the possibilities of using satellite images to assess water bodies, to calculate the trophic indicators of Lake Baikal according to existing models, adapting them, if necessary, to develop models for calculating biotic and abiotic indicators, to develop an integral assessment of the trophicity of Lake Baikal, and describe the algorithm for obtaining it. The object of the study is Lake Baikal. The subject of the study is the assessment of the reservoir’s trophicity. In terms of theoretical and methodological basis, the study relies on research works of Russian and foreign authors in the field of assessing the trophicity of water bodies, geographic information systems (GIS) as well as Earth remote sensing data (ERS). The methods of spatial analysis and correlation-regression analysis were used. The empirical and information-statistical bases of the work include statistical and analytical publications in the press on the topic under study, statistical data of the Russian Federation, foreign statistics, data from seminars and conferences on the problems of assessing the trophicity of water bodies, and the use of GIS and remote sensing data in assessing the state of water bodies. The scientific and practical novelty and significance of the results obtained lie in the development of an algorithm for assessing the trophicity of the reservoir using GIS and remote sensing. The parameters of models for calculating the Secchi disk transparency and chlorophyll-a concentration have been estimated. It is proposed to use rank assessment for express evaluation of the trophicity of water bodies, and an appropriate scale has been developed to determine the type of trophicity of the reservoir. An algorithm for estimating the trophicity of the reservoir is described.

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The significant contribution of oil and gas companies to the Russian economy is obvious. Changes in the financial state of these companies are also important for the economy as a whole. The aim of the work was to identify the factors influencing the financial state of the oil and gas companies and to predict the trends of changes. The data of the accounting statements of the oil and gas companies, statistical data of the State Statistics Committee, the Central Bank of the Russian Federation were used. For the analysis of fluctuations in the financial state, an integral indicator of the financial state is proposed, based on the liquidity, profitability and turnover ratios using average annual maximums as standards. Based on the dynamics of the integral indicator of the financial state of the company, OGCs are divided into three groups ("growth", "recession" and "maturity"). With the help of correlation-regression analysis, the dependence of the main financial indicators for oil and gas companies as a whole and for groups on fluctuations in the quotation of Brent oil on the world market and the exchange rate of the Russian ruble against the US dollar was estimated. It is noticed that companies in the "growth" group are directly dependent on the dollar exchange rate, while in the "decline" group the fluctuations in oil prices have the greatest impact. The companies of the "maturity" group do not practically depend on fluctuations in oil prices and exchange rates, but have an insignificant contribution to the total revenue. The largest oil and gas companies in the Russian Federation are in the "recession" group, therefore, fluctuations in oil prices, especially in connection with the onset of the economic crisis, will have a significant impact on the state of the industry as a whole.