DROUGHT EVALUATION WITH NDVI-BASED STANDARDIZED VEGETATION INDEX IN LOWER NORTHEASTERN REGION OF THAILAND

Drought is a natural phenomenon that usually occurs in various areas of the northeastern part of Thailand and it has a major impact on agriculture. The main objective of this studywas to apply remote sensing technology and the Standardized Vegetation Index (SVI) for the evaluation of drought in the aforementioned areas. For the implementation, data of the Normalized Difference Vegetation Index (NDVI) from the Terra/MODIS satellite was utilized for the analysis in order to examine the drought areas due to the change of the vegetation conditions by the SVI within a period of three years: 2014, 2015, 2106. According to the study, it was found that the worst drought was in 2016, followed by the years 2014 and 2015, respectively. Furthermore, for the reliability of this technique, the analysis results from the SVI to find the statistical relationship with the rainfall in the target areas was completed. The results of both sets of the data showed a high relationship in all three years (2014, R-2 = 0.83; 2015, R-2 = 0.88 and 2016, R-2 = 0.97). Thus, it could be concluded that examining the drought situation by remote sensing technology and the SVI at different periods in the areas of the Lower Northeastern region of Thailand could identify the forms of drought effectively.