耦合海-气环流模式中双热带辐合带现象及其热收支分析  

DOUBLE ITCZ PHENOMENON AND ANALYSIS OF ITS HEAT BUDGET IN A COUPLED OCEAN - ATMOSPHERE GENERAL CIRCULATION MODEL

作　　者：李江龙 张学洪[2] 俞永强[2] 戴福山[2,3] 

机构地区：[1]国家气象中心,北京100081 [2]中国科学院大气物理研究所,LASG,北京100029 [3]北京应用气象研究所,北京100029

出　　处：《气象学报》2003年第1期39-51,共13页Acta Meteorologica Sinica

基　　金：国家重点基础研究计划(G2000078502);中国科学院知识创新工程重要方向项目(ZKCX2-SW-210);优秀国家重点实验室研究项目(40023001)。

摘　　要：文中研究了耦合海-气环流模式中的双热带辐合带(Double ITCZ)现象,并对这一现象的成因从海洋热量收支的角度进行了初步分析。Double ITCZ现象是在热带太平洋赤道南北两侧各出现一条ITCZ的现象,这是耦合海-气环流模式中的较为普遍的一种异常现象,与实际气候中出现的Double ITCZ现象并非指同一问题。文中对比观测和模式结果,指出了Double ITCZ现象的主要特征,针对它的出现过程进行细致分析,再利用模式输出的热量收支各项进行统计,得到了从海洋热收支分析得到的海表温度变化原因。与观测到的正常模态相比,Double ITCZ是一个异常的模态,它的特征突出地表现为西太平洋暖池区的降温和东南太平洋10°S附近的升温。海洋热量收支分析表明,暖池区的降温主要是受到扩散的作用,而表层平流的异常增暖在决定异常辐合带区升温过程中占第一位的作用。The Double ITCZ phenomenon in a coupled ocean- atmosphere general circulation model (CGCM) is studied in this paper and primary analyses of the phenomenon are given from ocean heat budget. Double ITCZ phenomenon is that two ITCZs exist aside of the equator. In coupled circulation models, Double ITCZ is a common phenomenon that is different from that in real climate. Compared the results of numerical experiment with observation, the main characteristics of Double ITCZ are pointed. Different form normal pattern, the most pronounced features of Double ITCZ are to cold SST in warm pool of west Pacific Ocean and to warm SST in a band near 10°S of southeast Pacific Ocean. The transition process from a normal ITCZ condition in the initial state to a Double ITCZ mode in the equilibrium state of a coupled ocean-atmosphere general cirulation model is studied in the paper. The results indicate that the transition process happens very fast. And the wind field which also changes fast in tropical Pacific Ocean may play a considerable role in the forming process of Double ITCZ. With each term of ocean heat budgets calculated, the reasons for sea surface temperature changes are gained from analysis of ocean heat budget. Analysis of heat budget in ocean indicates that the SST cooling process in warm pool is mainly affected by diffusion, and the SST warming process in the band near 10°S in the eastern Pacific is affected by anomalous warm advection. This work has pointed out the reason for variety of sea surface temperature in a CGCM, which gave the primary analysis of Double ITCZ phenomenon. However, the further analyses are necessary to gain its explicit physical image.

关 键 词：耦合海-气环流模式 热带辐合带 热量收支 扩散 平流 

分 类 号：P731.21[天文地球—海洋科学]