1979年夏季我国东部各纬带水汽输送周期振荡的初步分析

本文根据1979年5—8月逐日850hPa的探空和测风资料计算了我国东部各纬度带平均的经向水汽输送,并进行了功率谱分析。结果发现与我国夏季雨带季节性北移紧密联系的水汽输送随着地理位置的变化呈现明显不同振荡特性。南海到华南地区,存在准40天和4天左右的显著周期;长江流域存在80天和8天左右的显著周期;华北地区存在5天左右的显著周期。并且综合分析表明,我国华南和东部地区的降水也呈现出40—50天的振荡特性,且与来自南海地区水汽输送的变化位相一致。 

A PRELIMINARY ANALYSIS OF THE PERIODIC OSCILLATION IN WATER VAPOUR TRANSPORTATION CROSSING DIFFERENT LATITUDES OVER THE EAST OF CHINA

Based on daily radiosounding data during the period of May-Augus at 850 hPa, the mean merid-ional water vapor transportations at different latitudes were computed over the East of China and a spectral analysis was carried out. It is found that the water vapour trans portations in summer exhibit different oscillation with the latitudes, closly related to the seasonal northward movement of the rainfall belt over our country, over the South China Sea-Southern China, the 40-50 day and 4 day oscillations prevail in the water vapour transportation; over Changjiang River reaches, the about 80 and 8 day periods are dominant while over Northern China the 5 day oscillation is signifcant By using composite method, it is also found that the rainfall over East China exhibits 40-50day oscillation feature in phase with the water vapor transportation from the South China Sea.