南海东北部海域中尺度涡的季节和年际变化

SEASONAL AND INTERANNUAL VARIABILITIES OF MESOSCALE EDDIES IN NORTHEASTERN SOUTH CHINA SEA

采用7a的T/P高度计资料对南海东北部海域海面高度异常及其季节变化和年际变化进行研究。研究表明该海域是中尺度涡的高能量区,尤其经常生成强的反气旋涡;海面高度异常的均方根高值区(即中尺度涡的高能量区)主要分布在台湾西南部(21.3°N,119.0°E)和吕宋岛西北(19.5°N,119.5°E)附近的深水海域;海面高度异常的均方根值随季节有明显的变化,春季是中尺度涡最弱的季节,均方根值最小,夏季次之,秋、冬是中尺度涡最强的季节,均方根值最大;海面高度异常的均方根值也表现出显著的年际变化,特别在ElNi no事件期间(1997年)其年均方根值最小。

The 7yr (1993—1999) TOPEX/Poseidon altimeter data were used to investigate SSH (sea surface height) anomalies and seasonal and interannual variabilities in the northeastern South China Sea. The analytical results show that it is a region with high energy of mesoscale eddies, where strong anticyclone eddies are frequently observed. The peaks of rootmeansquare (RMS) SSH anomalies are distributed at approximately (21.3°N,119.0°E)and (19.5°N,119.5°E) in the deep basin. There are significant seasonal changes of RMS SSH anomalies characterized by a minimum during the spring and a maximum between fall and winter. The RMS SSH anomalies are also subject to significant interannual variations. The interannual changes were particularly noticeable during the El Nio in 1997 when the annual RMS of SSH anomalies reached a minimum.