Comparison of Hydrological Responses by Two Different Satellite Remotely Sensed Leaf Area Indices in a Mountainous Watershed of South Korea

摘要

Vegetation information influences evapotranspiration (ET) and hence affects the hydrological cycle. Understanding the impact of biophysical variable such as Leaf Area Index (LAI) on watershed hydrology can clarify the water balance of a watershed. This study investigates the impact of vegetation information on ET, soil moisture, groundwater recharge and streamflow by using two different sources of spatial LAI data (Terra MODIS and NOAA AVHRR) in the calculation of FAO Penman-Monteith ET. For a 6661.3 km~2 mountainous watershed in South Korea, the SLURP (Semi-distributed Land Use-based Runoff Processes) hydrological model was calibrated and verified based on 4 years MODIS LAI data with average Nash-Sutcliffe model efficiency of 0.67. The results indicate that the two watershed ETs vary within 4%, and the deciduous and coniferous ETs vary within 6.8% and 11.2% respectively. The two ETs affected maximum 2.4%, 6.1%, and 8.8% differences of soil moisture, groundwater recharge, and streamflow respectively.