Method of Topographic Downscaling of Soil Moisture Fields Derived from Semi-Distributed Hydrological Models

The ECOMAG physically-based semi-distributed model as applied to the Ussuri River catchment area (24 400 km2) was used to demonstrate the possibility of using the results of modeling areal characteristics, presented in the form of discrete (average) values for the model subbasins of the model by continuous fields with the spatial resolution of the original DEM, on the basis of which the model spatial elements are defined. The spatial resolution of the results of hydrological modeling of the average soil moisture for a particular catchment area is increased by multiplying the low-resolution data of the source by a field of transition weights calculated on the basis of the indices of the relative position on the hillslope. The moisture field at the boundaries of subbasins is smoothed by the Tobler areal interpolation method, constructing a smooth surface while preserving the average value (of moisture volume) within particular catchments. The main aspects and possible limitations of the practical application of the proposed method are discussed.