동중국해에서 태풍 통과 후 관측된 내부파

Abstract

Four Autonomous Drifting Ocean Station (ADOS) drifters were deployed to understand variation of upper layer thermal structure in the Northwestern East China Sea in august 2007. Each ADOS drifter has ten or eight temperature sensors at intervals of eight meters and five or four pressure sensors at intervals of 16 meters. During the drifter experiment, the typhoon Nari passed the East China Sea. The typhoon Nari was occurred at 13th September 2007 in the northwestern pacific with the minimum central pressure at 940 hPa and the maximum wind speeds at 168 kilometers per hour and passed over the central area of the East China Sea at 15th to 16th of September 2007. Thermal structure of upper layer of the East China Sea was affected by the passage of typhoon in the East China Sea. Immediately after the typhoon passing, a distinct inertial oscillation signal is detected in both of the drifter trajectory and vertical thermal structure. We analyzed the time series and spectrum to describe variation of temperature and velocity field response to typhoon. Very strong thermocline was formed between 30 m and 50 m. After the typhoon, however, it was broken and temperature of upper layer abruptly dropped to about 4°C and increased to about 6°C at lower layer. Vertical oscillation by inertial wave with about 24 hours period is showed up very strongly for 4 or 5 days immediately after the typhoon passing. Trajectories of ADOS drifter between 16th and 20th of September show drifting northward as a clockwise rotating with 24 hours period, which is characterized the typical inertial wave around 30°N. We compare the results from the drifter experiment with data from Acoustic Doppler Current Profilers (ADCP) simultaneously deployed at 30°N to 32°N and 126.5°E to 127°E. The observed velocity shows that semi-diurnal tidal currents about 12 hours period are dominant during the whole observation period. During the passage of typhoon, however, inertial wave about 21 hours period distinct