MONITORING DROUGHT VIA TVDI DERIVED FROM 2000 - 2015 MODIS DATA: A CASE STUDY OF THE VIETNAMESE MEKONG RIVER DELTA

摘要

During the last decades, drought has appeared sparsely and repeatedly in the Vietnamese Mekong River Delta. The paper focuses on exploiting the 2000 - 2015 MODIS data in the dry seasons to monitor drought in this region via TVDI (Temperature Vegetation Dryness Index). For each image-acquisition time, TVDI has been applied to determine dry levels for each pixel. Here, TVDI is determined based on NDVI, derived from MOD09GQ data, and LST, derived from MODI 1 Al data. Then, for each pixel, a temporal trend of the mean TDVI changes is estimated by a linear regression in the 2000 - 2015 dry seasons. The results indicate that a state of drought in the Vietnamese Mekong River Delta has mostly been at a light and moderate levels for each dry season, corresponding to mean TVDIs from 0.4 to 0.8, usually occupying approximate 98% of the study area. Several areas in the center have an increased trend of the TVDI changes, while several areas in the maritime provinces have a negative trend.