毕节市50 a降雨量和雨日数气候变化特征

Characteristics of Climate Change of Precipitation and Rain Days in Bijie City during the past 50 years

选取毕节市七县一区1961-2013年的年降雨量和年雨日数资料,采用线性趋势、滑动平均统计方法,对53a降雨量和年雨日数的气候变化进行分析,结果显示：年降雨量和年雨日数的变化曲线基本一致呈减少趋势,进入21世纪以来,减少趋势更为明显,1984年之前、1995-2001年为多雨时段;1985-1994年、2002年之后为少雨时段;四季降雨量变化,除春季在2012年以来进入正距平区域外,其余季节仍为减少趋势,冬季减少缓慢.年雨日数总体呈减少趋势,2000年之前为多雨日数时段,2001年至今为少雨日数时段,四季雨日数变化除冬季减少缓慢外,其余3季减少明显.

Based on the data of the annual rainfall and rainy days during 1961--2013 in Bijie City, including seven counties and one district,the feature of the climate change of the 53-year rainfall and rainy days were analyzed with the method of linear trend and moving average statistic.. The resuh indicates that the change curve of annum rainfall and rainy days has a trend of decreasing and the decreasing trend is more obvious than before since the 21st century. During the years before 1984 and the period from 1995 to 2001, there were plenty of rain,while during the years from 1985 to 1994 and the period afte 2002,it rained very little. As for the variatiom of rain in the four seasons, there is a tendency of decreasing in all the seasons, with slow decrease in the winter time. However,in spring, it increases. Also, the annual rainy days show a trend of decrease, before 2000 many rainy days and since 2001 fewer rainy days.Rainy days＇ decrease is slow in winter while in the rest seasons the decrease is obvious.