本文采用有限区域p-σ混合坐标系五层原始方程数值模式,以美国地球物理流体动力实验室的10年月平均气候资料的纬向理想场作为初始场,对4-6月东亚大气环流及其月际变化的一些主要特征做了比较成功的模拟,如青藏热低压的形成与发展,高原南侧4月份"准季风经向环流圈"的出现,6月100mb青藏高压的建立,副热带西风急流的消失及东风急流的形成和长江流域雨带位置等都与实况基本一致。文中还讨论了:(1)高原南侧的"准季风经圈环流"与高原的热力作用;(2)高原地面反照率对高原及附近地面感热输送、大气增温及对东亚大气环流系统的影响;(3)6月我国东部降水的水汽来源和青藏高原南部、东南部及我国西南地区降水的水汽来源问题。

A numerical model and GFDL data are used to simulate the inter-monthly variation from April to June.It is found that the simulation is quite successful, for example, the formation and the development of the Tibetan Thermal Low, the "quasi-monsoon cell" to the south of the Plateau in April, the set-up of the 100mb Tibetan High in June, the with drawal of the westerly jet and the appearance of the eastely jet, the precipitation distribution along the Yangtz River and so on are all fairly simulated. Discussions are also given to (1) The quasi-monsoon cell and the thermal effect of Plateau, (2) the effects of the surface albedo in Plateau area on the transfer of sensible heat, the atmospheric heating and circulation, (3) the water vapour sources for precipitations over East China, southern and southeastern parts of Plateau and southwestern part of China.