An assessment of the VIC-3L hydrological model for the Yangtze River basin based on remote sensing: A case study of the Baohe River basin

Abstract

As a first step in our effort to simulate terrestrial hydrological processes for the entire Yangtze River basin, a hydrologically based three-layer variable infiltration capacity (VIC-3L) land surface model is applied to the Baohe River basin, which has a drainage area of 2500 km2. Water fluxes of the Baohe River basin are simulated using the VIC-3L model at a spatial resolution of approximately 4 km. The soil and land cover properties were taken from the resource and environment database (scale 1 : 4 000 000) of China (REDC). The vegetation and land cover data were also derived from the moderate resolution imaging spectroradiometer (MODIS) data over the study area. Measurements from a number of weather stations were used to obtain meteorological forcings for each modeling grid based on a stepwise interpolation approach (SIA). The VIC-3L model was run at a daily time step. Differences in model-simulated water fluxes resulting from using the two different data sources (i.e., MODIS versus REDC) on information of land cover classification and leaf area index (LAI) were compared. Model-simulated daily runoff was routed through the Baohe River basin network and compared with the daily observed streamflow measured at Jiangkou hydrological station at the outlet of the Baohe River basin from 1992 to 2001. Results from the VIC-3L model simulations using REDC data compare well with the observations in general, but the model-simulated streamflows often underestimate the observed peak flows significantly. In comparison, the underestimations of the peak flows are significantly improved when more accurate vegetation information on land cover and LAI from MODIS is used. The REDC land cover was obtained about 20 years ago with only six different types of vegetation that are generally distributed homogeneously throughout the study region. However, the land cover in the Baohe River basin is mainly mixed forest. The unrealistically large land cover area of deciduous broadleaf forest in the REDC data source resulted in an unreasonable increase in evapotranspiration and a decrease in streamflows. This study indicates clearly the important role that remote sensing (e.g., MODIS data) plays in improving model simulations. © 2004, Taylor & Francis Group, LLC. All rights reserved.