A CROP DROUGHT INDEX FOR GROUND TRUTH VALIDATION

摘要

Drought is a kind of widely existing nature hazard. Various drought indices have been developed to depict the drought conditions. However, there is no one index that may be applied to everywhere or in any circumstance. It is feasible to monitor drought in large area by using remote sensing, in particular for the crop drought. In order to verify and validate drought indices derived from remote sensing data, in particular categorize these indices into different level from severe drought to wet condition, it is strongly needed to collect the ground truth data of the drought as the reference. It is possible in some cases to depict the drought with the single index, like soil moisture or crop canopy water content but a single index is not able to extend widely due to the complexity of the drought. In order to develop a more powerful index, the field experiments have been carried out and the biophysics parameters that are related to the drought were observed. They are the chlorophyll content, crop water content, crop tempreature, soil moisture and soil temperrature. A comprehensive drought index was formulated based on these parameters and was used to depict the crop drought. This index is expected to evaluate the drought and used to collect the drought condition at large area and finally used to validate and verify the drought index retrieved from remote sensing data.