Inter-Decadal Variations Of Summer Precipitation In North China And Linkage Of It And General Circulation Of Atmosphere And Enso Cycle

Based on summer precipitation in North China and the Northern Hemisphere sea level pressure (SLP) and the Pacific sea surface temperature anomaly (SSTA) from 1900 to 2001 and NCEP data from 1950 to 1999, this paper studies inter-decadal variations of summer precipitation in North China and linkage of it and general circulation of atmosphere (GCA) and ENSO cycle using EOF and wavelet transform and composite analysis and correlation analysis and so on. Result shows that summer precipitation in North China has gone through four major dry-damp phases, richer periods from 1900 to 1915 and from 1946 to 1978, less periods from 1916 to 1945 and from 1979 to 2001, and has obvious inter-decadal variations, and has about 60a, 20-30a, 10a major periods and has twice abrupt changes in 1953 and 1979. Analysis shows that when summer precipitation in North China is richer (less), tropical east Pacific SSTA is colder (warmer) phase, and SLP and 500hPa geo-potential height are negative (positive) anomaly over the Asia, west Pacific sub-high is northerner (southerner), and block high in mid-highs latitude happens less (more) than normal, east monsoon is stronger (weaker). Analysis shows their possible physical linkages among them that when tropical east Pacific SSTA inter-decadal anomaly arouses anomaly of GCA, and lies East Asian tele-connection over Asia-Pacific area, then causes west Pacific sub-high and east monsoon anomaly, and cause summer precipitation inter-decadal variations in North China.