The use of NOAA/AVHRR data for flood disaster monitoring in the Mekong River Delta

The Mekong River Delta is one of the most important agricultural lands in Vietnam. Every year, it faces flood and water logging, causing a lot of problems and damages. NOAA/AVHRR data sets have been used successfully to monitor flood in this area. The method of Sheng (1996) has been modified, using information from different channels of NOAA/AVHRR data, including visible and infrared split window channels to remove cloud interference, including cloud shadows, when cloud contamination is not very high. The quantitative split window channel threshold value has been given for the identification of a waterbody and land surface under semi-transparent clouds. Hereby, a much wider ground area for any cloud coverage can be analyzed and detected, even under poor weather conditions. Techniques for objectively defining threshold values and the automatic running of the program for flood monitoring have been developed, as well as for the identification of the image's pixels with different rates of mixing between water and land. A case study for flood monitoring in the Mekong River Delta in late 1997 has been carried out. The results of flood monitoring on 15 November 1997 are shown as an example in this article.