利用Argo浮标资料分析横跨吕宋海峡20.5°N断面的水文特征

基于Argo浮标资料,分析了一条横跨南海北部、吕宋海峡和西太平洋（20.5°N,114°~130°E）断面的海水温度、盐度的分布特征.其结果表明：Argo剖面资料得到的2008年秋季20.5°N断面海水的温度、盐度分布态势与气候态秋季的分布基本一致,主要差异在于南海次表层水的盐度极大值和西太平洋次表层水的盐度极大值,2008年秋季二者均比气候态秋季的低0.1左右.通过动力计算（选取1 200 m为速度零面）表明：Argo浮标剖面资料与融合的卫星高度计产品得到的20.5°N,117.5°~124.5°E断面的表层地转流北分量的分布比较吻合;吕宋海峡中部（20°~21°N）的黑潮主轴大致位于121.5°E附近,其东边界可达123°E,而西边界仅限于121°E以西,其可能原因是该季节黑潮的左侧存在着一个气旋式环流,阻碍了黑潮西进;黑潮在20.5°N断面的体积流量为27×106m3/s左右,最大流速约为55 cm/s,出现在70 m层左右.

Hydrographical characteristics along the 20.5°N section through the Luzon Strait based on Argo data

This study was conducted to analyze the characteristics of temperature and salinity along the 20.5°N,114°~130°E section across the northern South China Sea,the Luzon Strait and the Western Pacific based on data collected by Argo profiling floats during autumn of 2008.The results showed that the characteristics of temperature and salinity along this section were close to those obtained from corresponding climatological data,with the major difference being that the maximum salinity in the subsurface layer in both the South China Sea and the Western Pacific obtained from the Argo data was about 0.1 lower than that obtained from the climatological data.Moreover,the northward component of the geostrophic current on the section（20.5°N,117.5°～124.5°E） was calculated with a reference to 1 200 m using dynamical calculation.The pattern of the northward component of the surface geostrophic current derived from the Argo profiling floats was similar to that derived from the merged altimeter products.The main axis of the Kuroshio was close to 121.5°E in the central region of the Luzon Strait（20°～21°N）,with the eastern edge of the Kuroshio reaching 123°E and the western edge reaching only 121°E.This may have been due to a cyclonic current on the left side of Kuroshio checking its westward movement.The net northward volume transport of Kuroshio was about 27×106m3/s in the 20.5°N section.The strongest northward flow of Kuroshio,about 55 cm/s,was found to occur at a depth of about 70 m.