利用Argo浮标资料研究西北太平洋三维声速分布特征

3-D characteristics of sound speed in the Northwestern Pacific Ocean with Argo float Data

利用西北太平洋海区2002～2009年的Argo浮标剖面温度、盐度资料构建成0.5°×0.5°水平分辨率的三维声速网格化资料,并据此分析该海区声速的空间分布及季节变化特征。研究表明:该海区10 m层等声速线分布的季节变化较为明显,春、冬季的等声速线几乎与纬线平行,黑潮流经区域等声速线呈现一定的弯曲。100 m层等声速线分布的季节变化较小:北赤道流区,等声速线从外海向近岸延伸;吕宋岛东南部沿海,等声速线向南弯曲;吕宋岛、台湾岛东部等声速线呈现偏北方向的弯曲;琉球群岛附近,等声速线朝北偏东方向弯曲。此外,研究海区存在深海声道,声道轴最深的区域主要在吕宋海峡和日本东南部海区,其中吕宋海峡处的声道轴有显著的季节变化特征。可见,利用Argo浮标资料可以初步得到西北太平洋声速的空间分布及其季节变化特征,随着Argo剖面资料的增多,对该海区的声速场认识将会愈加清晰。

We constructed a seasonally 3-D sound speed dataset with 0.5°×0.5° horizontal resolution, using the Argo profiles observed in the Northwestern Pacific Ocean during 2002-2009, and then analyzed the characteristics of spatial distribution and seasonal variation of sound speed. The results showed that the distribution of the sound speed contours at the 10 m layer varied significantly in different seasons; in spring and winter, the velocity contours approximately appeared to be zonal distribution and had some bending towards specific direction in the Kuroshio zone. The seasonal variation was not evident at the 100 m layer and the main features were as follows： the sound speed contours extended toward the coast in the North Equatorial Current zone, bended southward in the east of the southeast of the Luzon Island and northward in the east of the Luzon Island and the Taiwan Island, and bended northeastward near the Ryukyu Islands. In addition, there existed deep sound channel in most of the investigated area; the greatest depth of the sound channel axis was located in the Luzon Strait and the southeast of Japan, especially possessing a marked seasonal variation in the Luzon Strait. With the accumulation of the Argo float profiles, the sound speed distribution of the investigated area will become clearer.