Abstract:

Drought is an important factor on the progress of society and agriculture. Soil moisture has been considered as one of the most important indicators of soil conditions. There is some significance to reflect the soil moisture situation of the study region with characteristics of surface temperature /vegetation index space. In this paper, Chongqing was chosen as the study area and the study period was 2006. The characteristics of surface temperature /vegetation index spaces were built with the soil moisture data and less cloud cover MODIS products which were acquired at the same time. The Temperature Vegetation Dryness Index (TVDI) was built by two kinds of vegetation index (NDVI, EVI) and named TVDIN, TVDIE separately. Firstly, the difference of two kinds of TVDI reflected the soil moisture status was analyzed with soil moisture site data. Then, using the land-use cover data of MODIS, the spatial diversity of the surface soil water conditions of hilly and mountainous areas in Chongqing was analyzed. Finally, combined with the main land use types of the study area, the soil moisture status of each land cover type was explored. The results show that, TVDI can effectively reflect the spatial and temporal differences in soil moisture and is an effective means which can monitor the soil moisture status at real-time. Compared with TVDIN which built by EVI and TVDIE which built by EVI, TVDIE is more suitable for the monitoring of summer drought. The TVDI grade distribution of woodland and grassland is more uniform. So there is strongest water conservation capacity for the woodland and grassland, sparse second, the cultivated land weakest. Vegetation cover is very helpful for the water conservation and drought resistance, and soil moisture and land use types exist certain correlation.