Discrete dynamic-stochastic model of long-term river runoff variations

A model of long-term river runoff variations is proposed. The model is based on a difference stochastic equation of water balance on a watershed. Precipitation and evaporation on the watershed are simulated by stochastic, dependent, non-Gaussian Markov processes. Long-term river runoff variations are described by a component of three-dimensional non-Gaussian Markov process. It is shown that the autocorrelation and skewness coefficients for river runoff can be negative. The proposed model can be used to assess the effect of climate-induced variations in precipitation and evaporation regimes in a watershed on long-term river runoff variations.