层化对东海大陆架潮流垂向结构的影响

利用ADCP对东海大陆架定点(26°30.052′N,122°35.998′E)连续观测6个多月的海流数据进行分析研究,结果表明:层化对该海域潮流的垂向结构有显著影响,层化导致潮流流速、潮流椭圆长轴、椭圆率和倾角在通过密度跃层时发生较大改变。9月份,东海大陆架存在较强的密度跃层,层化加强,海流流速、M2分潮潮流倾角和M2分潮潮流椭圆率在跃层深度以浅随深度显著增大,跃层处达最大,跃层以深随深度迅速减小;2月份,上层海洋混合较强,密度跃层强度最弱,潮流流速、潮流椭圆长轴、椭圆率和倾角在垂向上变化不大。

EFFECT OF STRATIFICATION ON TIDAL CURRENT VERTICAL STRUCTURE ON CONTINENTAL SHELF OF THE EAST CHINA SEA

The tidal current profile data measured by ADCP in over six months on continental shelf of the East China Sea were studied. The observation is situated at 26°30.052'N, 122°35.998'E (113m depth) from September 20, 2008 to April 6, 2009. The temporal interval was 10 m. The spatial interval is 8m at 11 depth levels (24, 32, 40, 48, 56, 64, 72, 80, 88, 96, and 104 m). A total of effective 28519 sets of data were acquired. The temperature and salinity data used for this study are based on an Argo floater. The monthly grid points are obtained by fusion and interpolation of the CTD data with the Triangle Trans-Ocean Buoy Network (TRITON) in resolution of 1°×1°. The results show that the influence of stratification on tidal current vertical structure is significant. The tidal current velocity, major axes of current ellipse, ellipticity, and inclination changed remarkably through the pycnocline caused by stratification. In September, a strong pycnocline exists in the continental shelf. The tidal current velocity, inclination of M₂ constituent tidal current, and the ellipticity of M₂ constituent tidal current increase significantly downwards the pycnocline, reach the maximum at the depth of pycnocline, and then decrease quickly downwards passing the pycnocline away. In February, all these parameters change only slightly as the mixing in the upper mixed layer becomes strong and the pycnocline is weak.