Upper ocean response to the tropical cyclones in northwestern Pacific during 2001~2004 by Argo data
1. Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012
2. Lab of Ocean Dynamic Processes and Satellite Oceanography, Hangzhou 310012
3. Nanjing Institute of Meteorology, Nanjing 210044
Abstract: The response of upper ocean to the tropical cyclones in the northwestern Pacific during 2001~2004 was discussed and analyzed using the data from Argo profiling floats. The results showed that after tropical cyclones passed, about 55.6% of the profiles showed deepening of the mixed layer depth (MLD) with a scope between 0-60 m, which became more obvious within five days after the cyclones. Induced by strong turbulent mixing, the mixed layer temperature (MLT) on 77.8% of the observed profiles decreased, by 5ºC at the most; the mixed layer salinity (MLS) also decreased by 0.12 on average on 61.1% of the observed profiles. Accounting for 54% of the estimated surface velocities increased with an average increment of 30 cm/s, presenting a positive correlation to the wind speed, with a correlation coefficient of 0.06. The change of MLT showed a negative correlation to the wind speed, with the correlation coefficient of –0.15; The temperature decrease indicated a rightward bias, especially on the location 50~150 km to the right of the cyclone tracks; while the change of MLS had almost the symmetrical distribution on the two sides of the tracks. The MLD deepened more distinctly on the right side of the cyclones, up to the most in the range of 100~150 km. The change of MLD was negatively correlated to the initial MLD before cyclones, with the correlation coefficient of –0.42.
Key Words: Tropical Cyclones; Mixed Layer; Argo profiling float; Northwestern Pacific