This paper focuses on the rainfall spectrum and its evolution of North China in rainy season with summer monsoon decaying in interdecadal time scale. The interan-nual component of the rainfall is the dominant part, ac...This paper focuses on the rainfall spectrum and its evolution of North China in rainy season with summer monsoon decaying in interdecadal time scale. The interan-nual component of the rainfall is the dominant part, ac-counting for 85% of the total variance, and has been changed significantly during the last 30 years. According to wavelet analysis its 5a periodic spectrum suddenly disappeared in the late 1960s, and its biennial oscillation gradually become weaker and weaker since 1970, accompanied by the summer monsoon decaying. Contrarily, the interdecadal component is principal in the summer monsoon over North China and is very similar to the counterpart of the rainfall. Their interde-cadal parts are significantly correlated, and the correlation coefficient is nearly equal to the one of the original sequences. Besides, the dry and wet climate alternated with the mon-soon abrupt changes in the 1960s and the 1970s over East Asia, apart from North China, climate drifted from a light drought to a severe drought during the past 30 years.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.49875024)the National Basic Science Research and Developing Program(Grant No.G1998040901)National Key Laboratory LASG
文摘This paper focuses on the rainfall spectrum and its evolution of North China in rainy season with summer monsoon decaying in interdecadal time scale. The interan-nual component of the rainfall is the dominant part, ac-counting for 85% of the total variance, and has been changed significantly during the last 30 years. According to wavelet analysis its 5a periodic spectrum suddenly disappeared in the late 1960s, and its biennial oscillation gradually become weaker and weaker since 1970, accompanied by the summer monsoon decaying. Contrarily, the interdecadal component is principal in the summer monsoon over North China and is very similar to the counterpart of the rainfall. Their interde-cadal parts are significantly correlated, and the correlation coefficient is nearly equal to the one of the original sequences. Besides, the dry and wet climate alternated with the mon-soon abrupt changes in the 1960s and the 1970s over East Asia, apart from North China, climate drifted from a light drought to a severe drought during the past 30 years.
