吕宋冷涡的季节变化特征及其与风应力的关系

Seasonal variability of the Luzon cold eddy and its relation with wind stress

利用AVISO提供的1993年1月至2007年5月的多卫星融合海面高度距平(SLA)数据,对研究区域(15°～20°N,113°～121°E)SLA的季节变化特征进行了分析.其结果表明:吕宋冷涡发生在冬、春季,且该冷涡的发生、发展与局地风应力具有较好的相关性;当SLA变化滞后于风应力1个月时,SLA与风应力的负相关系数达-0.78;且当出现西南风时,SLA为正值;而在东北季风期间,SLA为负值.对SLA进行主成分分析得到的前2个模态反映了SLA的季节变化特性,其中第一模态的贡献率为54.14%,表现为以18.5°N,119.5°E附近为中心的SLA同步涨落,对风应力的响应迟滞1个月,而且此模态与风应力模第一模态的空间分布十分相似;第二模态的贡献率则为14.54%,表现为季风作用下海面高度的Ekman调整.

The MSLA （map of sea level anomaly）data （1993-01 -2007-05） from AVISO is used to analyze the seasonal variability, of SLA in the studied area （15° -20°N, 113° -121°E）. It indicates that the cold eddy northwest off the Luzon Island （ i. e. , Luzon cold eddy） occurs in winter and spring, and the local wind stress may have played an important role in inducing such a cold eddy, while the SLA distribution responses to the wind stress with a one-month time lag. The empirical orthogonal function （EOF） decomposition is also applied to analyze the SLA data, and the first two modes could largely explain the seasonal variability of SLA, with the first and second mode accounts for 54.14% and 14.54% of the total variance, respectively.