Soil moisture estimation using MODIS data over the head water of West Liaohe Basin, China

Soil moisture (SM) stored near the land surface controls the surface hydrological processes, especially runoff generation, soil evaporation and plant transpiration. Soil moisture is highly variable in both time and space, which leads to individual point measurements rarely representing the spatial average of even small areas. In this paper the spatial pattern and temporal evolution in TVDI has been analysed using 28 MODIS images of 2008 in Laohahe basin. Based on the so-called T-s/NDVI space in terms of surface soil moisture status and combined with the observed data, a profile estimation algorithm of relative soil moisture (RSM) was developed from MODIS data. Then we apply to the whole study area to estimate surface soil moisture. The result shows that this method can estimate the spatial distribution and temporal variation of soil moisture content over the soil profile from infrequent measurements of near-surface soil moisture (0-10 cm). The simulated RSM good well with the observed data (MAE = 16.86%). Finally, the spatio-temporal characteristics of RSM were analysed.