USING MODIS IMAGERY TO ESTIMATE THE DAMAGE OF RAINFED RICE IN NORTHEASTERN THAILAND

Northeastern Thailand is one of the representative rainfed lowland rice agriculture areas in Asia, where rice yield is limited due to unstable rainfall and poor soil. The area of rainfed lowland rice in northeast Thailand is approximately 5.27 million hectares, representing 57% of rice-growing area of the country. Heavy monsoon rainfall over central and northern Thailand began in July 2011 and lasted until October, causing a great impact on national agriculture. Huge tracts of farmland are submerged, threatening the annual rice crop. The objective of this paper is to assess the damage of regional rainfed rice after severe floods by using MODIS Surface Reflectance 8-Day L3 Global 250 m (MOD09Q1) and 500 m (MOD09A1). During the rice flooding period, Land Surface Water Index (LSWI) values are increased and even become higher than vegetation indices (Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI)). For this reason, the rice flooding period is a crucial indicator to identify the rice. The algorithm for mapping rice paddy uses time-series MODIS retrievals to identify the rice paddy in northeastern Thailand. The result indicates that the MODIS-derived rice evaluations are useful for obtaining spatial distribution maps of rice on a large-scale region.