Crop Drought Monitoring using MODIS NDDI over Mid-Territory of China

Drought is one of the major environmental disasters in north China, whereas in recent years it have happened in mid and southern of china seriously, so it is very important to detect and monitor drought periodically at large scale for decision making. Droughts can be assessed with many kinds of indices but it is extremely difficult to quantitatively monitor and predict. Remote sensing is able to supply us with an update on crop condition over a large geographic area using a series of coarse resolution satellites and this technology has become the important means of drought monitoring. In this study, the analysis was conducted on the combining information from visible, near infrared, and short wave infrared channels to improve sensitivity to drought severity. Using the normalized difference drought index (NDDI) that had a stronger response to summer drought conditions than a simple difference between NDVI and NDWI, and is therefore a more sensitive indicator of drought in Jiangxi province of mid-territory in china than NDVI or NDWI alone. With the support of land use map and soil humidity of crop for the growing season, we build a simple model of Jiangxi province of China for crop drought monitoring. The results of August 2007 show that the large scale temporal and spatial characteristics of drought over mid-territory of China can be effectively detected by this way. Based on this method, we have developed a operational crop drought monitoring system for Jiangxi province land areas.