东亚冬季风异常激发ElNio现象的数值试验研究  

Numerical Experiment on the El o Event Stimulated by the East Asian Winter Monsoon

作　　者：杨辉[1] 陈隽[1] 孙淑清[1] 

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029

出　　处：《大气科学》2005年第2期321-333,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究专项经费 (编号 :2 0 0 4CB41 830 3);国家自然科学基金项目 40 1 350 2 0 ;40 2 330 33和 40 32 50 1 5

摘　　要：用全球海气耦合气候模式和海洋模式进行各种敏感性试验 ,研究东亚冬季风异常对ElNi no事件形成的作用。结果表明东亚冬季风异常对于海洋热状态起了很大的作用。强冬季风年冬季所对应的海温距平为LaNi na型 ,但在与冬季风异常相对应的风应力作用下 ,通过海气相互作用 ,由于赤道西太平洋西风异常和海温正距平的东传 ,可以使海温向着ElNi no型分布发展 ;弱冬季风年冬季所对应的海温距平为ElNi no型 ,后期则会转成LaNi na型。冬季风异常的偏北风分量及赤道西风分量对海温所产生的影响各有差异 ,前者更多地影响太平洋西岸及暖池区 ,后者则对整个赤道太平洋热状态特别是ElNi no形成起了重要的作用。在ElNi no发展过程中起决定作用的主要不是风应力的强度 ,更关键的是异常风应力的持续时间。由于风应力的持续作用 ,ElNi no发展特征更加显著。与冬季风异常相对应的纬向风分量特别是西风异常在ElNi no发展中起主导作用 ;在单纯的海洋模式中经向风异常只能改变局地的西太平洋海温 ,并不能使东太平洋海温产生响应 ,即没有出现赤道暖水的东传过程。试验表明 ,海气耦合模式较单纯的海洋模式能更好地反映海气相互作用及ElNi no的形成。Based on numerical experiments of the Global Ocean-Atmosphere-Land System Model and the oceanic general circulation model developed by State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics, the influence of East Asian winter monsoon (EAWM for brief) on the occurrence of El Nio is studied. Sensitivity experiments show that the anomalous EAWM would greatly affect SST in the tropical region. The strong EAWM is associated with a La Nia pattern of SSTA (SST anomaly) in the tropical region in winter and even to the following summer. However it would gradually change to an El Nio pattern from the following autumn resulting from the forcing of west wind stress connected with the strong EAWM in the western tropical Pacific. The warm SSTA center in the western Pacific shifts eastward. For the weak EAWM situation, the process will be reverse. The SSTA would vary from an El Nio pattern in the winter associated with the weaker EAWM to a La Nia pattern after the following autumn. The effects from meridional and zonal components of EAWM on the SST are different. For the former, the main effect is concentrated on the western coast of the Pacific and the warm pool area. However the zonal component of EAWM would influence the SSTA in the whole tropical region, and then stimulate the development of the El Nio event. The decisive factor for the wind stress forcing on the development of the El Nio is how long the forcing effects rather than the strength itself. When an ocean model is used instead, it indicates that the zonal component of EAWM play a main role in the development of El Nio. For the meridional component of EAWM, the variation of SSTA only occurs in the western Pacific region and there is no shift of warm SSTA center from the western Pacific to the east. It indicates that the air-sea coupled model is much better to describe the air-sea interaction and the development of the El Ni n～o, in comparison with the ocean model.

关 键 词：季风异常 El 东亚 试验研究 海气相互作用 太平洋海温 激发 数值 海洋模式 NINO事件 赤道西太平洋 海气耦合模式 海温距平 西风异常 敏感性试验 赤道太平洋 风应力 气候模式 应力作用 赤道西风 发展过程 持续时间 发展特征 

分 类 号：P426.616[天文地球—大气科学及气象学] TN383.1[电子电信—物理电子学]