ABSTRACT. This brief study depicts the changes of water properties (temperature and salinity profile) after Typhoon Ketsana passed over the South China Sea and the benefits contributed to marine life as well as human being. Argo float data near the typhoon track before and after Typhoon Ketsana, available from GODAE website was analyzed in this project. Cooling of sea surface temperature (SST) about 1 to 3 °C was recorded in the study area. Typhoon Ketsana had removed about 250 to 380 MJ of heat from a surface area of 1 m². Sea surface salinity was observed to be increased about 0.2 to 0.4 pss after the typhoon. In addition, thermocline and halocline depths have deepened about 7.8 to 12.6 m and 10.3 to 12.9 m respectively due to the increase of surface layer depth. Even though the lifespan of Typhoon Ketsana was short, it brought several positive impacts: removed heat from the tropic regions in order to maintain moderate temperature, increased the concentration of nutrients due to the increases of salinity thus enhancing phytoplankton bloom in the ocean. Furthermore, the typhoon changed the ocean structure by deepening the thermocline and halocline depths. This affects the behavior of marine organisms that perform vertical migration. From the rough estimation, if the heat energy removed by Ketsana could be harnessed and converted into electricity, it would support the electrical usage in Malaysia for many years. Therefore, this study may cause some people to change their perspective on typhoons. In fact typhoons causes not just destruction and tragedy they also bring positive benefits to human kind and marine environment.
KEYWORDS. Halocline, SST, SSS, thermocline, typhoon