2009年夏季东沙群岛附近内孤立波的现场观测

Internal solitary waves at the Dongsha Islands observed in the summer of 2009

通过对东沙群岛附近2009年夏季测到的三个孤立波事件的分析,结合现场的X波段雷达、ADCP和CTD观测,发现内孤立波经过时,伴有突发性强流,最大水平东西分量U大于0.5 m/s,周期大约15 min,各深度层海流均为西向。第三个孤立波事件中,雷达后向散射影像中包含至少4个亮条带,其中最后的条带雷达表面信号最强。而内波表面信号强弱不仅与内波的振幅有关,还可能与潮流、混合层深度等环境条件有关,该研究可加深对内波遥感观测的理解。

Three internal solitary waves （ISWs） around Dongsha were observed in the summer of 2009. Based on in situ onboard X-band radar, thermistor chains, ADCP and CTD data, we found that during the internal solitary waves passing the vessel, there was a strong abrupt current, with maximum east-west speed （U） of more than 0.5 m/s, and the whole course was about 15 minutes. All the deep ocean currents faced west. During the third instemal solitary waves, there were at least four light stripes in the radar backscatter power images, and the strongest internal wave surface signal lied at the rear of the stripes. Besides the amplitude of ISWs, the background current and mixing layer depth may also have impact on sea surface signal power. This study is very helpful to understanding of ISWs remote sensing and examination.