Dynamic-Stochastic Modeling of Long-Term Runoff Fluctuations in the Oka River: «doing Hydrology Backward»

The results of dynamic-stochastic modeling of long-term runoff fluctuations in the Oka River basin are presented. River runoff is treated as the output process of a hydrological system, with precipitation and evaporation over the catchment as input processes. The Friedmann–Keller method was used to estimate the unknown statistical characteristics of evaporation and effective catchment moisture storage. These characteristics were determined by solving a system of equations linking the statistical characteristics of precipitation, evaporation, and river runoff. Thus, we solved an inverse hydrological problem or, using Kirchner’s term, performed “doing hydrology backward”.