Abstract:It is shown that the relationship between the phase of 50 hPa QBO in winter and the summer drought/flood trend in the lower and middle reaches of Changjiang River is characterized by very marked stages. For the entire period of 1953-1989, the relationship between them is very weak. But according to the data they could be devided into three stages.The relationship in each stage is very strong.And the anomalous evolution of 50 hPa QBO is examined that shows to be related properly with the stratifying of the three stages.

Abstract:On a microcomputer the comprehensive analysis is made on the diagnosis of physical quantities, radar echoes, satellite cloud pictures, wind profile by UHF radar, data about lightning and remotely-sensed water vapor, etc. in a partly man-computer interactive manner, and than the commended forecast by the microcomputer is put forward. This will serve for inproving the accuracy of forecasting severe convcctive weather, systems in flood seasons in Bejing-Tianjin-Hebei area and for forecast automation.

Abstract:In this paper, the relationship between the tropical cyclones landing on China and the El Nino events is statistically analysed. The results show that of the tropical cyclones and typhoones landing on China are less in El Nino years and more in anti-El Nino years. So are the landing latitudes. The degree of these relationships is diverse in different moths and latitude regitons. Its possible reason is caused by abnomal Walker and Hadley Circulation and the position of Subtropical high ridge during the. El Nino events.