Yearly variations in runoff as a function of precipitation variations for the East-European plain

Variations in climatic conditions for the East-European Plain (EEP) are analysed. The observations show that the time periods of high-water and low-water correspond to certain circulation conditions, which points to a conceptual possibility to construct a model correlating streamflow with atmospheric precipitation. Described is a linear model based on a regression equation for the principal components of runoff and precipitation. The model presents the best results for a territory where a strong reaction of the river water to a certain circulation type has been established beforehand.