Responses of Yellow Sea Cold Water Mass to Typhoon Bolaven

摘要：A two-month seabed-mounted observation(YSG1 area)was carried out in the western Yellow Sea Cold Water Mass(YSCWM)using an RDI-300K acoustic Doppler current profiler(ADCP)placed at a water depth of 38 m in late summer,2012.On August 2012,Typhoon Bolaven passed east of YSG1 with a maximum wind speed of 20ms^-1.The water depth,bottom temperature,and profile current velocities(including u,v and w components)were measured,and the results showed that the typhoon could induce horizontal current with speed greater than 70cms?1 in the water column,which is especially rare at below 20 meters above bottom(mab).The deepening velocity shear layer had an intense shear velocity of around 10cms?1m?1,which indicated the deepening of the upper mixed layer.In the upper water column(above 20mab),westward de-tide current with velocity greater than 30cms?1 was generated with the typhoon’s onshore surge,and the direction of current movement shifted to become southward.In the lower water column,a possible pattern of eastward compensation current and delayed typhoon-driven current was demonstrated.During the typhoon,bottom temperature variation was changed into diurnal pattern because of the combined influence of typhoon and tidal current.The passage of Bolaven greatly intensified local sediment resuspension in the bottom layer.In addition,low-density particles constituted the suspended particulate matter(SPM)around 10 mab,which may be transported from the central South Yellow Sea by the typhoon.Overall,the intensive external force of the Typhoon Bolaven did not completely destroy the local thermocline,and most re-suspended sediments during the typhoon were restricted within the YSCWM.