大凌河流域朝阳区域降水日数变化特征

Variation Feature of Precipitation Days in Chaoyang Area of Daling River Basin

为了服务＂三农＂发展农村经济,建立防灾减灾服务平台,利用1957～2012年大凌河流域朝阳区域气候监测站降水资料,分析了不同量级降水日数的时空变化特征。结果表明：降水日数总体呈减少趋势,尤其≥0.0 mm、≥5.0 mm降水日数减少显著。全年降水日数减少主要在夏季,而夏季降水日数的减少主要出现在7～8月。7～8月≥0.0 mm降水日数气候倾向率为-1.382 d/10年,线性减少约8 d;≥5.0 mm降水日数气候倾向率为-0.719 d/10年,线性减少约4 d;≥10.0 mm降水日数气候倾向率为-0.389 d/10年,线性减少约2 d。近20年（1993～2012年）由于7～8月降水日数的减少,伏旱的发生几率达到35.0%。

In order to serve the ＂Three Dimensional Rural Issues＂to develop rural economy,and to establish the disaster prevention and mitigation service platform,analyzed the temporal and spatial variation characteristics of different orders of magnitude of the number of days based on the precipitation data of climate monitoring stations in Chaoyang area of Daling river basin from 1957 to 2012. The results showed that the number of precipitation days decreased,especially the more than 0.0 mm and the more than 5.0 mm precipitation days decreased significantly. The annual rainfall days were mainly in summer,and the decreasing of the number of days in summer was mainly in July to August. The climate tendency rate of precipitation days during July to August with more than 0.0 mm was- 1.382 d / 10 a,linear decreasing was approximately 8 d. The climate tendency rate of precipitation days more than 5.0 mm was- 0.719 d / 10 a,linear decreasing was approximately 4 d. The climate tendency rate of precipitation days more than 10.0 mm was- 0.389 d / 10 a,linear decreasing was approximately 2 d. Over the past 20 years（ 1993 ～ 2012）in July to August due to a decreasing in precipitation days,drought incidence reached 35.0%.