Verification of the impact of drought in central region of Thailand

Abstract

Drought is one of the problems in the agricultural sector of Thailand. It affects the cultivation season and agricultural products. The central region of Thailand is an important agricultural area, so the verification of drought is necessary. This research aims to obtain drought maps and to verify the abnormal drought month in the central region of Thailand by using the Normalized Difference Drought Index (NDDI). The calculation of NDDI was based on Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) that was calculated by evaluating data from MODIS09 Terra satellite images 500m resolution from January 2010 to December 2019. Drought maps were obtained by representing NDDI maps as drought maps. After comparing the maps with the announcement published data, it was found that during the study period there was abnormal drought. The most abnormal drought months were 9 months in 2010. Abnormal drought was often occurring in January, March, April, May, and June. Most of drought areas were in the middle of the region. The NDDI value was more accurate when there was occurred by El Niño phenomenon and lack of precipitation but there was not suitable to flooding area. IMPLICATION OF THESIS Suggestion for the further research 1. This research can be used in the future to verify the drought in Thailand by the classification. The drought should be reclassified relying on the data of the study area. It cannot use the same classification in this study due to the different studied areas which have different terrain and climate, especially rainfall. 2. The results reveal that rainfall or precipitation affect the NDDI value so the percent of rainfall should use to study with NDDI. 3. NDDI cannot use in flood areas.