Cruise observation of shallow water response to typhoon Damrey 2012 in the Yellow Sea

Abstract

Typhoon Damrey 2012 has been the strongest typhoon to strike the area north of the Yangtze River since 1949. Two cruise observations to examine the shallow water response to typhoon were carried out just before and after the passage of Damrey in the shallow water near the Jiaozhou Bay on 1 and 5 August 2012. The observation results indicate that, after the passage of Damrey, the thermocline was deepened and weakened significantly. The water temperature below the surface increased by about 4–10°C. A significant temperature gradient was generated at the bottom of the water column. The salinity decreased throughout the water column. The surface heat flux and precipitation data indicate that the temperature increase and salinity decrease of the bottom water were mainly caused by the intrusion of warm, low-salinity water from the surface (depth < 7m). The model results suggest that the mechanism that drive the variations as follows: the warm low-salinity surface water was driven by wind and flowed onshore, accumulated and sank as it encountered the coast, which forced the cold bottom water of the Yellow Sea Cold Water Mass (YSCWM) to flow offshore.