热带西太平洋大气气候基本态与厄尔尼诺期间赤道附近西风异常  

The role of atmosphere climate basic state in the formation of westerly over the equatorial Pacific

作　　者：严邦良[1] 张人禾[2] 

机构地区：[1]中国科学院大气物理研究所,北京100080 [2]中国气象科学研究院,北京100081

出　　处：《海洋学报》2002年第2期39-50,共12页

基　　金：国家重点基础研究发展规划项目(G199804900)第一部分;国家自然科学基金项(49975019).

摘　　要：利用合成分析的方法分析了自1961年以来观测到的8次厄尔尼诺事件中赤道西太平洋地区西风异常与大气气候基本态的关系,结果发现厄尔尼诺年赤道西太平洋地区西风异常具有和大气气候基本态相一致的季节变化特征.利用一个简单热带海-气耦合模式较好地模拟出了观测到的厄尔尼诺年赤道西太平洋地区西风异常的变化特征.对模式结果的分析表明,大气气候基本态对厄尔尼诺年赤道西太平洋地区西风异常的形成起重要作用,它是通过影响大气模式中的加热场来影响赤道西太平洋地区西风异常.大气模式中赤道太平洋地区的加热场的形成具有阶段性和地区性,在厄尔尼诺事件的初始阶段,大气气候基本态是大气模式中的加热场形成的主要因子,而在厄尔尼诺事件的发展和成熟阶段,赤道中东太平洋地区的海表温度异常（SSTA）是加热场形成的主要因子.模式模拟结果对大气气候基本态依赖的敏感性试验说明,在大气模式加热场中含有大气气候基本态的模拟中,沿中西太平洋赤道附近的纬向风异常表现出和观测类似的传播特征.The relationship between atmosphere climate basic state and westerly wind anomalies over the equatorial western Pacific is studied by using composite method during 8 El Nino year since 1961. It is found that the western wind anomaly over equatorial western Pacific shows clear seasonal variability similar to that in the atmosphere climate basic state. These characteristics of seasonal variation are successfully simulated with a simple equatorial ocean-atmosphere coupled model. The model results show that the atmosphere basic climate state is very important for generation of western wind anomaly over the equatorial western Pacific. Atmosphere basic climate state effects on the western wind anomaly over the equatorial western Pacific through the heating in the atmosphere model. The effects of SSTA and atmosphere climate basic state on the heating in the atmosphere model vary with the phase of ENSO cycle and geographical location. In the beginning of ENSO cycle, the atmosphere climate basic state plays an important role in forming heating field in the atmosphere model over the equatorial Pacific. During the developing or mature phase of ENSO cycle, the SSTA plays a more important role in forming heating field in the atmosphere model over the mid-eastern equatorial Pacific. Sensitive test of the coupled model to atmosphere climate basic state was made. It shows that the propagating characteristics of westerly wind anomaly along the equatorial Pacific close to the observations.

关 键 词：厄尔尼诺事件 海气耦合模式 大气气候基本态 太平洋 西风异常 

分 类 号：P732[天文地球—海洋科学]