Study on winter wheat drought monitoring by TVDI in Hebei Province

Abstract

Droughts hazard that occurrs frequently in nature and has a great impact on agriculture. Timely monitoring and assessment of drought conditions are critical to mitigate its effects. By using NOAA/AVHRR satellite data, in current study, we derived the normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI) and land surface temperature (LST), and analyzed the spatial characteristics of vegetation indexes and land surface temperature. The temperature vegetation dryness index (TVDI) was used to monitor the winter wheat drought conditions from March to May of 2005 in the middle-south part of Hebei Province, China. The results showed that SAVI was better than NDVI for representing the winter wheat growth condition in spring. The correlation of soil moisture with TVDI based on SAVI was greater than that of based on NDVI. The analysis of TVDI and soil moisture data from weather stations' measurement demonstrated that a better correlation existed between TVDI and relative humidity of soil at 10cm and 20cm. TVDI therefore can be used as a good indicator for operational drought monitoring.