Remote Sensing Analysis of Impact of Typhoon on Environment in the Sea Area South of Hainan Island

MODIS derived Chlorophyll a concentration (Chl-a), Particulate Organic Carbon (POC) and Sea Surface Temperature (SST) as well as QuickScat wind and TRMM derived accumulated rainfall data were analyzed to investigate the Chl-a and POC increase in tongue feature in the sea area south of Hainan Island. Results showed that the high Chl-a concentration area in tongue feature appeared after the passage of typhoon Washi over the middle of Hainan Island from east to west on July 30 2005. The high Chl-a and POC area stretched along 18° N to the deep interior of the SCS was detected on August 1 2005, and lasted for about one week. The formation of the Chl-a in tongue feature is caused mainly by increased load of terrestrial nutrient which was with the increased rainwater runoff during typhoon. Second the Ekman transport generated by the strong wind during typhoon. In addition, the changes of sea surface currents contributed to the stretch of the high Chl-a to the SCS. The large increases of POC after passage of typhoon indicates that typhoon play an active role on global carbon cycle. Typhoon is important for the mitigation of increasingly prominent greenhouse effect.