热带大气环流平均状况的研究

应用NMCl7年热带u、v风及OLR资料研究了热带地区大气环流的平均结构和特征。指出热带大尺度环流基本上是由东西向的walker环流和南北向的Hadley环流所组成的。这些环流是由热力作用直接驱动的,它具有高低层风向相反的特征。扰动风场与平均风场有密切关系。西风基本气流对应着扰动动能的极大值而东风则对应着扰动动能的极小值。热带地区存在着明显的辐散辐合作用,它也是由热力作用引起的并与热带对流活动有密切联系。 

A STUDY ON THE MEAN ATMOSPHERIC CIRCULATIONS IN THE TROPICS

The climatological structure and characteristics are studied using the 17-year NMC monthly winds and OLR data. It is found that the tropical circulation consists of zonal Walker Cells and meridional Hadley Cells. They are directly driven by the thermal difference in the tropics. The wind directions in upper troposphere and in low level are often opposite. There is a close relationship between the mean flow and the perturbation field. The maximum perturbation kinetic energy is linked with the westerly basic flow and the minimum perturbation kinetic energy is linked with the easterly. There are also strong divergence fields in the tropics and they are closely related to the convective activities in tropics.