1979年梅雨期季风垂直环流的一些特征

本文通过1979年分析发现在梅雨期间,我国东部江淮地区上空存在一个稳定的季风垂直环流圈。这个环流圈在梅雨期间的平均图上表现十分清楚,其南北范围约1500公里,顶部可达100百帕,中心约在距地7—9公里之间。它的上升支恰好对应梅雨雨带,它的存在、维持和消亡对梅雨有直接影响。在这个平均季风垂直环流圈的北侧,本例中没有发现对应的闭合反环流圈。热力场的分析指出,青藏高原初夏时期的增热对季风垂直环流的演变和梅雨的形成有一定的影响。

SOME FEATURES OF THE MONSOON VERTICAL CELL DURING THE MEIYU PERIOD IN 1979

By analizing data of 1979 it is shown that there is a stable monsoon vertical circulation cell over the Changjiang-Huaihe Reaches in eastern China.The circulation cell is very clear on the average map of monsoon period. It's meridional scale is about 1500km with a top up to 100 hPa. At vertical direction its centre can be found about 7-9 km from surface. The ascending air of the cell coincides with the Meiyu rain belt. The existence, maintenance and decay of the cell influence the evolution of Meiyu directly. In this case no closed inverse circulation cell is found to the north of the average monsoon circulation cell.It is also shown through a thermodynamic analysis that the Qinghai-Xizang Plateall heating in early summer has a close relationship with the evoluting of the monsoon vertical cell and the formation of Meiyu.