Application of MODIS data for assessment of evapotranspiration and drought in Northern China

摘要

The objectives of this study are to explore the performance of MODIS remote sensing data in large scale ET and drought mapping based on physical consideration of land surface energy balance. It was revealed from the analysis results that ET derived from MODIS data was in very good agreement with the measured by lysimeter with the consistency index of 0.917, correlation coefficient of 0.872, and daily relative error of-11.34%. Further, regional water stress index (RWSI) was derived from ET by remote sensing demonstrated a strong correlation with field measured soil moisture and is more significantly correlative to mean 0-20cm soil moisture. The case study conducted for fall drought monitoring in North China during years 2005-2006 indicated that the spatial distribution of drought conditions evaluated from RWSI was in good agreement with actual precipitation and drought status. As the efficient method on the basis of relative soil moisture and ET by MODIS data only with Yucheng station measurements, yet more extensive validation with field measurements at regional scale is necessary to be done to discriminate the effects and the accuracy of the proposed RWSI method.