WANG Qun-ying GONG Dao-yi

WANG Qun-ying
(Institute of Geography, CAS, Beijing 100101)
GONG Dao-yi
(Department of Geophysics, Peking University, Beijing 100871)

Abstract: Rainfall resource is very important to social-economic system, especially to North China which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1951 to present, the characteristics of precipitation changing over North China and its possible connection to El Nino were studied using tendency analysis, correlation analysis and wavelet analysis. Results showed that the rainfall in North China had a down tendency in summer and autumn at a rate of£­9.6mm/10a and £­4.5mm/10a respectively. And annual precipitation was decreasing at the rate of £­12.9mm/10a. In decadal time scale, abrupt changes were observed in the mid-1960s for summer and annual precipitation. Precipitation was significantly less for the decade after about 1985 in contrast to the decade before. The time series showed perio-dicities at 2£­4, 8, 20 years for summer rainfall and at 2£­4, 8 years for autumn rainfall. El Nino had prominent impacts on precipitation of North China, under El Nino condition the rainfall will decrease significantly in summer and autumn, and increase in spring.

Keywords: North China, rainfall, El Nino