1982-1983年冬季厄尔尼诺期间大气环流异常的诊断分析

A DIAGNOSTIC ANALYSIS OF GENERAL CIRCULTAION ANOMALY DURING THE EL NINO PROCESS FOR THE WINTER 1982/83

摘要:

本文利用ECMWF的逐日资料,对比分析了1982年12月和1980年12月的平均大气环流情况,结论是:1982—1983年El Nino事件对全球大气环流有重大影响。(1)El Nino事件不仅使Hadley环流得到加强,而且使所有经圈环流都有所加强;(2)El Nino事件使两个半球(特别是北半球)的中纬度西风加强,使对流层低层及中纬度200hPa附近的温度升高,中纬度的对流层低层有弱的降温;(3)El Nino事件使大气湿度明显增加,但在北半球副热带地区除近地面层外湿度都明显减小。 同大气环流基本状态的异常相应,El Nino事件也导致了大气中动量、热量和水汽输送的明显异常。这些物理量输送的异常不仅同平均环流的异常有关,而且扰动(特别是行星尺度的扰动)对此也有着重要贡献。

Abstract:

Comparisons of December general circulation means between 1982 and 1980 conclude that the El Nino event in 1982/83 had a great impact on global atmospheric circulation in that (1) it intensified both the Hadley and meridional circulations; (2)it streng thened mid-latitude westerlies in both hemispheres (especially the northern hemisphere), resulting in a temperature rise for lower troposphere and 200 hPa mid-laittudes and mild drop for lower tropospheric mid-latitudes; (3) it dramatically increased the atmospheric temperature while lowering it significantly for northern subtropical regions except for near-suface layers.Corresponding to the anomaly of the basic state of the atmospheric circulation, the El Nino anomaly also causes obvious anomalies in the transfer of momentum, heat and moisture, the transfer is strongly affected by both the anomalies of the mean circulation and the perturbations, especially those at planetary scales.