The Features of the Catastrophic Flood over the Changjiang River Basin during the Summer of 1998 and Cause Exploration
1998年夏长江流域特大洪涝特征及其成因探讨

By use of the observational data, the climatic and hydrological features of the catastrophic flood over the Changjiang River basin during the summer of 1998 are analysed, its cause is also explored. The possible cause is shown as follows, during the transition of El Nio event from the mature stage to decaying stage in ENSO cycle, sea surface temperature in the tropical Pacific particularly sea subsurface temperature in the tropical west Pacific becomes cooler, the convection activities around Philippines decrease, thus the west Pacific subtropical high is located more southward, as a result, an abundant moisture from the Bay of Bengal and South China Sea carried by Asian summer monsoon converges with moisture from the tropical west Pacific and the westlies first in the middle and lower reaches of the Changjiang River and then in the upper and middle reaches, causing continuously severe rainfall in the Changjiang River basin.