Variation Characteristics Analysis of Precipitation in Chengdu

By use of the recent 30 years’ precipitation data of Chengdu from 1981 to 2010, an analysis is made of the time change feature of the precipitation time. The results show: the overall precipitation sees a slight decreasing trend in the area under investigation, the recent ten years in particular, sees an accelerated decrease in this respect; the precipitation time sequence exist three primary period changes at 6.5a, 12a and 19.5a respectively, of which the periodic oscillation of the 19.5a energy is the most powerful.