Comparison and analysis NDVI and RVI changes before and after typhoon in Hainan based on HJ-1CCD satellite images

Typhoon is one of the most sever natural disasters. Monitoring the typhoon timely and quickly is very significance for Agricultural disaster assessment and post-disaster reconstruction. HJ-1 CCD remote sensing images were used to study the changes before and after typhoon intrusion, taking NO.17 severe Nesat of 2011 as an example. Selected two CCD images, including July 8th, 2011 and Dec. 25th, 2011, then extracted the NDVI and RVI information of 7 farms before and after typhoon with the course of image pretreatment and vector cutting. Subsequently, extracted the NDVI of 7 farms from July 5th, 2011 and Dec. 27th, 2010 for comparative analysis. The result shows that: (1) the RVI value of 7 farms were larger than NDVI value. (2) The NDVI variation characteristics are identical to those of RVI. Because of the typhoon influence, the value of NDVI and RVI in 7 farms decreased at different degree, and RVI decline more rapidly. The research shows that the value of NDVI and RVI is possible to monitor typhoon impacts on vegetation by using HJ-1CCD images.