Abstract
The character of tendencies of change of the average seasonal sums of rainfall in the extensive territory of Kazakhstan can be various and it is essential to influence and even to change the republic structure of sown areas. The main objective of the study is to evaluate and compare statistical characteristics, as well as trends in the changes in average seasonal precipitation over the past decades. The average seasonal values of precipitation sums for spring, first and second half of summer were calculated for six stations in East Kazakhstan, the variability characteristics – mean square deviations (CAO) and coefficients of variation were calculated and analyzed. The characteristics of the normal distribution of the average seasonal sums of precipitation (asymmetry and kurtosis coefficients) have been estimated, histograms of precipitation sums for the above seasons at the Ayaguz, Bakhty, Katon-Karagai, Pavlodar,Semey, Ust-Kamenogorsk and averaged over the eastern Kazakhstan seasonal precipitation. The trendsof these amounts change for each of the above stations and for precipitation averaged over the territoryof East Kazakhstan are determined. Trends in seasonal precipitation in spring, in the first and second halfof summer for individual stations, indicate a significant and insignificant increase in seasonal precipitation,and averaged over the territory of seasonal amounts – for significant growth in recent decades inall the considered seasons of the warm period of the year. This is also indicated by the annual amount ofprecipitation, which increased during the period under study.