• 论文 •

### 夏季风活动与长江流域的旱涝

1. 中国科学院地理研究所
• 出版日期:1982-03-15 发布日期:1982-03-15

### SUMMER MONSOON ACTIVITY AND THE DROUGHT OR FLOOD OF THE CHANG-JIANG RIVER

Xu Shuying

1. Institute of Geography, Academia Sinica
• Online:1982-03-15 Published:1982-03-15

Abstract: In this paper,an analysis is made firstly that the summer monsoon activity corresponds with the distribution of the main rain field in China, Rainfall here largely concentrates in the spell of summer monsoon. The total amount of annaul or seasonal rainfall may be close to normal for a particular year. But it does not mean that the rain fall in all parts of China will be approximate to normal, some parts may get more or less rain, whereas other places may suffer from drought or flood disasters.Secondly, the author summarized the characteristics of the upper and lower tro-pospheric circulation over the droughts and floods of the Chang-Jiang River, and found that there are close relationships between the summer monsoon activity and the position of the western pacific subtropical high, with its ridge stretching either westward or eastward.Particularly, the subtropical circulation and the interactions between the Tibetan high and the western Pacific high play an important role in drought or flood of the Chang-Jiang River.Finally, some fundamental factors in the formation of monsoou and its possible effects on the activity of summer monsoon are discussed. We have analyzed the climatic conditions in a period before the drought or flood, and found there are some fundamental factors influencing summer monsoon activity and the drought or flood in the Chang-Jiang River. For example the winter or spring monsoon circulations, the sea surface temperture in equatorial east Pacific ocean, the differential heating of the continent and ocean surface over Eastern Asia, the temperature variation of the Tibetan Plateau, the time of upper troposphere wind variation from westerlies to easterlies and so forth, do have a substantial influence on the onset of summer monsoon. These results.may be helpful for long-range forecasting of rainfall and the activity of summer monsoon.