Impact On Ocean Environment Induced By Twin Typhoons Over Northwest Pacific Ocean-case Study

Northwest Pacific Ocean is a remarkable region for highest number of typhoons over the World.Tropical cyclones as an important physical process in the ocean have a key impact on marine local and non-local thermodynamics and kinetics and other aspects.It is of great scientific and practical value to study the response of the upper ocean to tropical cyclones to understand the coupling mechanism of biogeochemical and physical processes in the air-sea interface.Furthermore,this research can provide effective value for typhoon's forecasting.In this paper,through the Argo observation data?the satellite remote sensing data combined with HYCOM data during typhoon "Saola" and "Damrey" ,we focus on the thermodynamic,dynamic response characteristics and rainfall characteristics of tropical cyclones "Saola" and "Damrey" in 2012.We have obtained with quantitative results,and the response mechanism of tropical cyclones in the upper ocean of the Northwest Pacific and rainfall characteristics were analyzed.The results are as follows:?1?Typhoon "Saola" and "Damrey" are two typhoons formed and landed all on same day on Pacific Ocean.The most characteristic of typhoon "Saola" is the slow movement and large size.Typhoon "Damrey" moves fast with small size.The airflow of Typhoon "Saola" has an effect on the airflow around "Damrey" .?2?The maximum temperature drop during Typhoon "Saola" crossing occurred on August 1,and the intensity reached 4.0°C,which was mainly due to the strong drop of sea surface temperature caused by the upwelling.The maximum cooling was 2.9?due to Typhoon "Damrey" ,the biggest reason for the performance was vertical mixing.Typhoon "Damrey" was weakened by the typhoon "Saola" ,mainly reflected in the left side of the cooling intensity of Typhoon "Damrey" .?3?Prior to the formation of tropical cyclones,upper ocean heat content was very high and provided sufficient heat for the development of the typhoons.There are differences in response to the typhoon "Saola" and "Damrey" in different depths in the ocean.Using HYCOM data,we found that the depth of the mixed layer was deepened by an average of 20-35 m.Typhoon "Damrey" led to the deepest mixing layer to 85.2m,the deepened mixing layer around the typhoon "Saola" was less than "Damrey" .?4?During the passage of typhoon "Saola" ,there is a strong upwelling in the low temperature zone with a suction velocity of less than 1.5×10^-3m·s^-1.When Typhoon "Damrey" moved fast,the vertical mixing of sea water mainly caused cooling effect.There may be a transition between ascending and descending flow within the Ekman layer.?5?During passage of typhoon "Saola" and "Damrey" ,there are three areas of heavy rainfall.And these value of three areas all over 250mm.The maximum latent heat flux is not at the center of the typhoon,usually in the rain zone.The value of latent heat flux can affect the intensity and distribution of rainfall.