Modeled Oceanic Response and Sea Surface Cooling to Typhoon Kai-Tak

• Published in: TAO : Terrestrial, atmospheric, and oceanic sciences Vol. 21; no. 1; pp. 85 - 98
• Main Authors: Tseng, Yu-Heng, Jan, Sen, Dietrich, David E., Lin, I-I, Chang, Ya-Ting, Tang, Tswen-Yung
• Format: Journal Article
• Language: English
• Published: Taiwan 中華民國地球科學學會 01.02.2010; Chinese Geoscience Union (Taiwan); Springer
• Subjects: Advection; Air-sea interaction; Bathymetry; Computer simulation; Hurricanes; Inertial oscillations; Mixed layer; Ocean circulation; Ocean models; Oceanic response; Oceans; Rossby number; Satellite imagery; Sea surface; Sea surface cooling; Sea surface temperature; Spaceborne remote sensing; Stratification; Surface cooling; Surface temperature; Surface wind; Typhoon; Typhoons; Upwelling; Wind; Wind fields; Wind shear; Winds; Typhoon; Air-sea interaction; Upwelling
• ISSN: 1017-0839; 2311-7680
• DOI: 10.3319/TAO.2009.06.08.02(IWNOP)

An ocean response to typhoon Kai-Tak is simulated using an accurate fourth-order, basin-scale ocean model. The surface winds of typhoon Kai-Tak were obtained from QuikSCAT satellite images blended with the ECMWF wind fields. An intense nonlinear mesoscale eddy is generated in the northeast South China Sea (SCS) with a Rossby number of O(1) and on a 50 - 100 km horizontal scale. Inertial oscillation is clearly observed. Advection dominates as a strong wind shear drives the mixed layer flows outward, away from the typhoon center, thus forcing upwelling from deep levels with a high upwelling velocity (> 30 m day-1). A drop in sea surface temperature (SST) of more than 9°C is found in both observation and simulation. We attribute this significant SST drop to the influence of the slow moving typhoon, initial stratification and bathymetry-induced upwelling in the northeast of the SCS where the typhoon hovered.