Dynamics of climate extremes in Western Siberia
L.A. Ogurtsov1, N.N. Cheredko1, M.V. Volkova2, G.G. Zhuravlev2
1Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, 634055, Tomsk, 10/3, Academichesky ave
2National Research Tomsk State University, 36, Lenin Avenue, Tomsk, 634050,Russia
Keywords: extreme temperature indices, precipitation extreme indices, Western Siberia, synchronicity of changes, extreme temperature indices, precipitation extreme indices, Western Siberia, synchronicity of changes
Abstract
This paper presents the analysis results of the space-time structure of temperature and precipitation extreme indices. Four indicators were chosen to represent temperature indices, and four indicators, to study precipitation indices. For calculating the indices we used daily data for 75 meteorological stations in Western Siberia for the period 1961-2013. The period under study was divided into two intervals: 1961-1990 and 1991-2013 for assessing the trends. The results show the statistically significant decrease in the frequency of cold days and nights for the period 1991-2013 as compared to the period 1961-1990 at some stations. Conversely, we found a slight increase of warm extreme temperatures. The tendencies of extreme precipitation indices indicate a high irregular distribution in Western Siberia. Results show negative trends for all extreme indices of precipitation only in the northern part of the territory considered. The study shows here a decrease in the number of days with precipitation of different intensity by 1-2 days. The south territory is characterized by a growth of precipitation indices by 1-2 days. The results show that precipitation extreme indices mainly insignificantly change in the average from period to period. This may be due, in part, to a sparse observational network, especially north of 60 degrees latitude, which confirms the need to optimize it. Most optimally this problem can be solved through the use of autonomous automatic measuring systems. Using the principal component analysis, we found that the temperature indices have a relatively high synchronicity in changes on the studied territory. This fact may be due to the contribution of large-scale processes. On the other hand, the analysis of the extreme precipitation shows inconsistency in its changes within the territory. This may confirm that local factors over different parts of the selected area impact significantly the formation of precipitation.
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