Methodical issues of evaluating methane capacity in small thermokarst lakes of Western Siberia permafrost

Abstract

The relevance of the paper is caused by the need to develop methodological issues of using mathematical modeling and ultrahigh resolution satellite imagery to assess the accumulation of methane in small thermokarst lakes in the permafrost zone, which are considered as the most active sources of methane emissions to the atmosphere in the Arctic and Subarctic regions under global warming of recent decades. The main aim of the study is to develop methodological issues of assessing the amount of methane accumulation in thermokarst lakes in the permafrost, based on mathematical modeling and ultrahigh resolution satellite images. Methods: remote sensing of thermokarst lakes fields, including small lakes, using satellite images of high and very high spatial resolution and techniques of geographic information systems for the analysis of satellite images, the methods of mathematical modeling of the spatial structure of the thermokarst lakes fields in permafrost landscapes, methods of biogeochemical studies of water bodies to determine the concentration of methane. The results. On the basis of biogeochemical studies the authors have determined that methane concentration in small thermokarst lakes (with area less than 200-250 m2 ) is on average about 13 times higher than its concentration in water of lakes, which are more than 250 m2 . Based on the remote research data on high resolution images the authors defined the parameters of the model that allows calculating fields of thermokarst lakes in the conditions of permafrost. The authors developed and described the procedure for determining methane accumulation volumes in thermokarst lakes located in a particular territory of the permafrost zone.

Keywords

• permafrost
• geoinformation systems
• satellite imagies
• climate changing
• mathematical modeling