Litvinova O.S., Gulyaeva N.V.
Novosibirsk state pedagogical university
According to the data obtained from 16 meteorological stations under the statistic analysis on monthly mean precipitation total during 1936-2006 there have been defined the main trends in precipitation variability in cold, warm and annual periods in landscapes of the Ob-Irtysh interfluves. There have been used data collected by A. P. Slyadnev land-climate zoning scheme based on zonal landscape boundaries determined by optimal conditions of humidity and heat supply. The catalogues of abnormally humid (∑ О ≥ 120%) and dry (∑ ≤ 80%) periods have been composed. Precipitation variability in different periods: 1936-2006, 1936-1980, 1961-1990, 1981-2006 and 1991-2006 has been analyzed. As a whole for the considered period 1936-2006, in comparison with the base period (1961-1990) during the warm period reduction of deposits only in the north of region (-18 mm) is established, during the cold period in the last 25 years (in comparison with 1936-1980) the insignificant increase in northern provinces is marked. The role of precipitation during different months in the formation of humid and dry periods in various landscapes has been also investigated. The correlation analysis has been conducted to define the role of G. Y. Wangenheim – A.A. Girs circulation forms in the formation of abnormal humidity periods. In landscape provinces interfluves Ob and Irtysh the greatest repeatability of the abnormal periods of humidifying is characteristic for steppe provinces. Formation of the extreme periods (dry and damp) is marked at development of atmospheric processes of forms of circulation W and C. In 1981-2006 the increase in deposits during the cold period of year in northern provinces (Vasjugansky and Barabinsk) is marked against growth of repeatability of forms of circulation W and C. The increase quantity of deposits is observed for the account activization of an exit of cyclones formed in moderate widths of the northern hemisphere, and in a warm season to become more active local cyclogenesis. The quantity of deposits decreases in connection with strengthening anticyclonic activity, especially with activization of the anticyclones displaced from the northeast, west, and southwest.
Key words: аnomalies of deposits, the atmospheric circulation.