2005～2010年南海海平面异常升高的特征与机制

Characteristics and mechanism of the sea level rise in the South China Sea during 2005～2010

利用高分辨率卫星高度计观测海平面异常（SLA）数据, 结合潮位站观测资料, 研究2005-2010 年南海海平面异常升高的空间分布特征.结果表明, 南海海平面显著上升, 平均速率为17mm·a^–1, 上升速率在空间分布上存在显著差异.速率最大的海域出现在南海中西部, 大于30mm·a^–1, 而南海南部海域上升速率则相对较小, 大约为12mm·a^–1, 潮位站的观测结果与卫星高度计观测结果一致.1993-2004 年期间南海海平面线性变化主要与海面经向风场变化导致的海面温度变化密切相关; 2005-2010 年3 次强La Nina 事件导致南海呈显著的正SLA; 此外, 受南方涛动、北太平洋的年代际振荡（PDO）等的低频变化影响, 南海中部海盆呈显著的东风异常, 由此在南海中西部海域产生负的风应力旋度, 是该海区海平面显著上升的另一重要因素.

Based on the high spatial resolution satellite observation data of sea level anomalies (SLA) and tide gauge station observations, we studied spatial pattern and mechanism of the anomaly high sea level in the South China Sea (SCS) during 2005~2010. The results showed that the basin mean sea level in the SCS had an increasing rate of about 17 mm·a–1 during 2005~2010 and that the spatial distribution of the increasing rate had significant differences in the SCS. The largest rate appeared in the central-west SCS, with an increasing rate of more than 30 mm·a–1; on the other hand, the increasing rate was relatively small in the southern SCS, at about 12 mm·a–1, consistent with the results using tide gauge station data. During 1993~2004, the sea level trend in the SCS was closely associated with the sea surface temperature anomalies caused by the variability of meridional wind. During 2005~2010, three strong La Ni?a events led to abnormally high sea level in the SCS. In addition, affected by the low-frequency variation of the Southern Oscillation and the North Pacific decadal oscillation (PDO), the wind stress displayed strong easterly wind anomaly in the central-west basin of the SCS, resulting in anomaly negative wind stress curl, which also led to abnormally high sea level in the SCS.