海洋平流的季节变化对La Nia事件成熟位相锁定的作用  

The Role of the Seasonal Variation of the Oceanic Advection in theLocking of the La Nia Event Mature Phase to the End of the Year

作　　者：严邦良[1] 

机构地区：[1]中国科学院大气物理研究所,北京100080

出　　处：《大气科学》2005年第2期283-291,共9页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目 40 2 31 0 0 5;中国科学院知识创新工程重要方向项目KZCX3 SW 2 1 8

摘　　要：用一个中等复杂程度的热带海气耦合模式模拟LaNi na事件成熟位相锁定在年底左右的特征并研究其形成的机制。结果表明 ,模式能很好地模拟观测到的LaNi na事件成熟位相锁定在年底左右的特征。LaNi na事件成熟位相锁定在年底主要由海洋气候基本态引起。海洋垂直平均流是LaNi na事件成熟位相锁定在年底左右的最主要因子。由海洋气候基本态的季节变化所引起的冷平流的季节变化是LaNi na事件成熟位相锁定在年底的机制。在LaNi na事件期间 ,1～ 5月份 ,赤道中东太平洋地区的冷平流较弱 ,它不能平衡海气热量交换过程的影响 ,因而海洋表面温度增加。这一过程使海气耦合不稳定度减弱 ,从而使LaNi na事件衰减。 6～ 12月份 ,赤道中东太平洋地区的冷平流较强。海气热量交换过程的影响不能平衡较强冷平流的影响 ,因而海洋表面温度减小。这一过程使海气耦合不稳定度加强 ,从而使LaNi na事件发展。这样 ,LaNi na事件成熟位相容易出现在年底左右。An intermediate complex ocean-atmosphere coupled model is used to simulate the characteristics of the mature phase locking of the La Nia event and explore the mechanisms of the locking of the La Nia event mature phase to the end of the year. The results show that the model can simulate the characteristics of the locking of the La Nia event mature phase to the end of the year. The oceanic climate basic state is responsible for the locking of the La Nia event mature phase to the end of the year. The upwelling is the most important factor for the La Nia mature phase locking. The seasonal variation of the advection generated by the seasonal variation of the oceanic climate basic states is the mechanism of the locking of the La Nia event mature phase to the end of the year. During La Nia event period, the cool advection, generated by the oceanic climate basic state from January to May, is weaker over the middle and eastern equatorial Pacific. The weaker cool advection makes the Sea Surface Temperature Anomaly (SSTA) increase, which makes the ocean-atmosphere coupled instability strength decrease, thus, the La Nia event decays. And the cool advection, generated by the oceanic climate basic state from June to December, is stronger over the middle and eastern equatorial Pacific. The stronger cool advection makes the SSTA decrease, which makes the ocean-atmosphere coupled instability strength increase, thus, the La Nia event develops. Finally, a minimum of cool SSTA occurs at the end of the year, which forms the La Nia event mature phase.

关 键 词：NINA 位相锁定 季节变化 LA 事件 成熟 海洋表面温度 气候基本态 太平洋地区 海气耦合 交换过程 不稳定度 冷平流 模式模拟 复杂程度 模拟观测 主要因子 12月份 平均流 5月份 机制 特征 中东 赤道 热量 平衡 热带 

分 类 号：P467[天文地球—大气科学及气象学] O411.1[理学—理论物理]