5.1 Parameterization
The parametrization of the Hydrograph model was performed based on joint analysis of available field descriptions of ground hydrothermal regime and corresponding patterns of runoff formation in typical landscapes (Vinogradov et al., 2011). According to altitudinal zonation, the catchment of the Suntar river is divided into 4 RFCs which are presented above: goltsy (RFC #1), mountain tundra (RFC #2), sparse larch forest (RFC #3), swampy sparse larch forest at waterlogged soils (RFC #4) (Fig. 1). For each RFC, a schematization of the vertical profile is developed that considers vegetation, soil composition, snow accumulation features and runoff formation processes. In the Hydrograph model the soil column is divided into computational soil layers (CSL), which may have different depths but it is usually taken to be equal to 10 cm, and the total depth of the calculated soil profile should exceed the maximum active layer depth, if the model is applied to the permafrost zone. In this study the calculation depth of the ground column was taken as 2 meters (20 CSL by 10 cm). This value is assigned from the assumption of maximum possible active layer depth (150 cm) (Grave, 1964).