Comparison of 4 Remote Sensing Drought Indexes for Drought Monitoring in Eastern Inner Mongolia

The eastern part of Inner Mongolia is a high-risk area for drought disasters, it is necessary to use remote sensing to monitor drought conditions. In order to study the applicability of different remote sensing drought indices in eastern Inner Mongolia, MODIS data in the eastern part of Inner Mongolia from late April to late September 2016 were used to calculate four commonly used remote sensing drought indices:temperature condition index (TCI), vegetation condition index (VCI), temperature vegetation drought index (TVDI) and vegetation supply water index (VSWI), and compared with meteorological drought composite index (MCI) and soil relative humidity data. The results show that TCI and VCI had a large deviation in drought monitoring at the beginning of the growing season due to the different reviving periods. The drought indices were basically consistent with drought in the middle and late growth seasons. VCI and MCI had the highest correlation with soil relative humidity. The consistency of MCI with VCI and VSWI was higher in the middle and low coverage grassland, while the highest consistency with TCI was toward to the middle and high coverage grassland. Combined with the characteristics of various drought indices, VSWI is recommended for drought monitoring in eastern Inner Mongolia during the early growing season, and VCI or TCI is recommended for drought monitoring in the middle and late growth season.