The assessment of thermal air condition and the trends in anticyclogenesis in southern West Siberia and its applicability

In this paper, the assessments of changing meteorological and calculated temperature parameters of surface air which are known to feature the present climatic conditions over the territory of Tomsk Region are given. The tendencies of anticyclogenesis over southern West Siberia and its potential effect on the thermal condition are shown. The data on diurnal resolution in air temperature at the weather stations of Tomsk Region for the 1941-2010 period and the Tomsk station for the 1891-2010 period as well as on the condition of anticyclone activities over West Siberia were used. The estimation of temperature conditions in different time series - for the mentioned above periods taken as a whole, for the 30-year periods and for the period of time in accordance with local building requirements - was made using the statistical methods of time series analysis. The mean values of daily air temperatures above the defined ranges (0, 5, 10, 15, 20 °С), the duration of extreme air temperature periods (> 30 and 35 °С, < -25, -30, -35, -40 °С), belonging to the dangerous weather events, absolute extremes of air temperature, as well as their probable marketable features (with 92, 95, 96, 98, 99 % occurrence) are established. The study of long-term air temperature trends for the last 40 years (1971-2010) revealed the temperature growth up to 0.4 ^ 0.6 °С every 10 years, the trends in some months (February - March) of the cold period reaching 1.5 ^ 1.7 °С every 10 years whereas the temperature did not change in April and September. Statistics of dangerous temperature events at the regional stations are given. Dangerous events associated with low temperatures were found to predominate in Tomsk Region and, what is more, they are long-term. The most vulnerable and exposed to the dangerous events in question are northern and north-eastern territories. It was shown that the dangerous event "heat wave" is not typical of Tomsk Region. The information on economic losses caused by dangerous temperature events is given. The estimations of probable features are given in moving 30-year periods, making it possible to analyze the temperature value dynamics as compared with the present local building requirements (1925 - 1980). The persistent increase in temperatures with 90% occurrence was found at the Tomsk station and, as a consequence, increases in air temperature during the coldest days. One can infer that the circulatory mechanism of activation of blocking the zone transition in the atmosphere gave rise to the increased frequency of dangerous events either with extremely low or with extremely high temperatures in those years. The assessment of changing the values of the thermal condition given in the paper implies its variable impacts on the activities of the economic complex in the southern West Siberia.

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