Use of NOAA/AVHRR data for flood disaster monitoring in Mekong River Delta

ABSTRACT

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 hardships and damages. The NOAA/AVHRR data have been used to monitor flood in this area. The method of Sheng Yongwei (1996) has been modified, using information from different channels of NOAA/AVHRR data, including visible and infrared split window channels to remove cloud influences, including cloud's shadows, when cloud contamination is not very serious. The quantitative split window channel threshold value has been given for an identification of waterbody and land surface under semi-transparent clouds. By this way, much wider ground areas for any condition of the weather, for any kind of the cloud systems can be analyzed and detected. The techniques for objectively defining the threshold values and automatically running the program for flood monitoring have been developed. A technique for identifying the image's pixels with different rate of mixing between water and land has been developed too. The case study for flood monitoring in Mekong River Delta in the late 1997 year was done and the results of flood monitoring on 15 November 1997 is shown in the paper as a demonstration