Integrating hybrid runoff generation mechanism into Variable
Infiltration Capacity model to facilitate hydrological simulation
Abstract
The runoff generating processes and water fluxes exchange are essential
simulating the physical nonlinear rainfall-runoff relations in
hydrological models. However, current runoff generation representation
in hydrological models is constraint due to both vertical and horizontal
heterogeneity of meteorological factors and underlying surface
condition, hampering the streamflow simulation performances. To address
this concern, by integrating a hybrid runoff generation mechanism in the
upper layer and baseflow curve in the lower layer, this work develops a
modified Variable Infiltration Capacity (VIC) hydrological model. With
consideration of both vertical and horizontal heterogeneity runoff, the
modified VIC model can simulate Horton and Dunne runoff through the
hybrid mechanism and lateral runoff based on three soil-layer structure.
The upper reach of Hanjiang River basin with substantial climate
variations is selected as a case study to validate the performance of
the modified model. Results show that the modified VIC model can produce
a better performance of streamflow simulation in terms of Nash-Sutcliffe
Efficiency, at around 0.8 on average, especially for semi-humid and
mountainous catchments. In addition, parameters related to the hybrid
mechanism are sensitive to the hydrological performance, indicating that
the improved performance should be attributed to the hybrid mechanism.