【摘要】 本文采用有限区域五层原始方程模式,以多年月平均的纬向场作为初始场,利用实际资料计算得到的1979年7月东亚地区的平均加热场作为理想加热场,进行了四类不同方案的数值试验。通过模拟得到的温压场及流场等结果,讨论了青藏高原大地形及其加热场的作用。分析结果表明:1.在大尺度地形的纯动力作用影响下,在对流层中、下层,西风气流过高原仍是以绕流为主,这种地形扰动在中纬度(40°N以北)表现得比低纬度明显,在对流层下层比对流层中层明显,300mb上动力扰动已很不明显。2.青藏高原产生的热源(例如,青藏高原感热源和潜热源以及孟加拉地区的潜热源),对于夏季100mb和300mb的强大的亚州反气旋的形成,对500mb以下印度低槽的加深及南亚副热带高压(以下简称南亚副高)带的断裂都有重大贡献。3.夏季,东亚地区的流场受加热场的影响比温压场更为明显,比如500mb以下与海洋地区相通的强大南风通道和加热场有密切关系。4.夏季,在东亚地区50°N以南存在着一个天气尺度的季风环流系统——“季风流管”,这一流管在考虑了加热场的影响后,被很好地模拟出来了。相反,在纯动力作用的试验中,它却始终没有出现,在高原以及南部被Hadley流管所占据。从分析结果来看,孟加拉地区热源对“季风流管”的中段与南段贡献较大。孟加拉地区热源?更多还原

【Abstract】 In order to investigate the effects of large-scale topography and heating sources and sinks induced by it on the mean general circulation in East Asia in summer, we use a 5-layer primitive equation numerical model developed originally by Kuo and Qian to make four kinds of experiments. The topography used in the model is close to the real one. The heating sources and sinks of the model are the stationary ones’ computed by Yiao et al. with the actual data of July, 1979. The initial geopotential heights used in this investigation are taken from mean July zonal average. We have done 4 experiments of simulation.The first one ( designated by HN ) has no diabatic heating but orography included and the second ( by HH ) has both diabatic and orographic factors included. Because in summer the two most important heat sources are located at the Qinghai-Xizang Plateau and Bangladesh region, respectively,in East Asia, therefore based on the HH experiment we designed the third and the fourth experiments. The third (by PN ) has no heating in Plateau, while the fourth(by MN ) has no heating in Bangladesh region. In this paper a detailed comparison of the four experiments with one another is given.更多还原