Summer Drought Assessment Based on Vegetation Supply Water Index in Chongqing

This paper choose MODIS product data of single-day and 8d synthesis from June to September in 2006 to construct vegetation supply water index (VSWI) for Chongqing summer drought condition, and validated results by soil moisture; while the correlation between VSWI and precipitation is discussed, and spatial and temporal distribution of drought in Chongqing were gotten using 8d synthetic data. The results showed that: (1) VSWIE built by EVI was more suitable for monitoring summer drought in Chongqing than VSWIN built by NDVI, and VSWI built by single-day MODIS data has better correlation than VSWI built by 8-day synthetic MODIS data; (2) VSWI had a certain negative correlation with precipitation; (3) VSWI could effectively reflect the spatial and temporal differences in soil moisture, and it was an effective mean to assess summer drought.