Application of the method of stochastic background forecast to Kazakhstan’s river basins

Abstract

The production functions of water-dependent sectors of the economy along with labor and capital investments include natural resources, in particular, the hydrological characteristics (norm, variation and skewness coefficients) determining the river flow dynamics. The purpose of the study is to test the method of stochastic forecasting of hydrological characteristics with lead time of 24 hours for the catchments of Northern Kazakhstan during the spring flood, which is characterized by a sharp rise and fall. The stochastic background forecasting method is based on solving a system of differential equations for initial statistical moments. Only average daily values of water discharge, which does change during the day but is not measured and recorded, are usually taken into account, making a statistical generalization of intraday variations in water discharges. The solution of simultaneous equations for the initial moments with daily resolution is the predicted values of the first three moments, characterizing the average daily value, the variation of water flow within a day and the deviation of the average value from the modal one (coefficient of skewness). Verification forecasts of the first and second initial moments have been made for the flood period with lead time of 24 hours. Optimization of the forecast system parameters has been carried out on 30 days preceding the forecast release date. It has been found that the first moment is predicted more reliably rather than the second one. The forecast of such statistical characteristics allows to obtain the frequency curve necessary for the production functions of the Kazakhstan economical sectors.