Typhoon Haikui induced sea surface temperature cooling and rainfall influence over Zhejiang coastal waters

Abstract

Strong winds in typhoons cause upwelling/mixing of seawater and hence a reduction in sea surface temperature (SST). The SST cooling depends on the intensity and translation speed of the typhoon. In this paper, typhoon Haikui’s induced SST cooling was analyzed with satellite-derived data. Haikui produced SST cooling on both sides of the track: the right-side cooling was due to upwelling/mixing (which depend upon the intensity of the typhoon), and rainfall induced SST cooling on the left side. Typhoon Haikui induced SST cooling over the coastal region was found to be about 1.9 ºC due to lower translation speed leading to upwelling, and also due to rainfall. The spatial extent of the cooler SST increased after the typhoon made landfall, especially over coastal regions. SST cooling over the study area has an inverse relation both to the typhoon’s translation speed and to rainfall. Due to heavy rainfall and air-sea interaction processes, SST cooling was higher on coastal waters, and cool waters persisted for a few days after the typhoon landfall.