Estimation of Land Surface Temperature and Vegetation Dryness Index (TVDI) in Bac Binh – Binh Thuan using Remote Sensing Images

Abstract

Nowadays, drought is regarded as one of the most destructive natural disasters which causes negative impacts on societies around the globe. Especially, in Binh Thuan province - Vietnam, the drought tends to increase in both scale and intensity but it is harder to be forecast. In recent years, with the development of remote sensing technology, its products have been used effectively in studying, monitoring and reacting to drought. Thus, in this study, we aim to determine the progress of drought through the years in Bac Binh district - Binh Thuan province by using remote sensing images. In details, we use images from Landsat 7 ETM+ (2002, 2005, 2010) and Landsat 8 OLI (2014 and 2017) to estimate dryness indices: temperature vegetation dryness index (TVDI) and improved temperature vegetation dryness index. These two dryness indices are based on normalized difference vegetation index (NDVI) and land surface temperature (LST) for TVDI and gradient of temperature (Ts-Ta) for iTVDI. The obtained results show that almost Bac Binh's area is estimated to have medium and higher drought risk, and its severe drought areas increased rapidly in 2014, 2017. High drought risk areas are found mostly in agricultural or non-vegetated areas in the center of Bac Binh.