正宁县秋季降水的气候特征及影响分析

Climatic Characteristics and Influence Analysis of Autumn Precipitation in Zhengning County

采用正宁国家气象观测站1971―2020年的降水资料,分析了正宁县秋季(9—11月)降水气候变化特征。结果表明,(1)近50年正宁县的秋季降水量整体呈略增加趋势,增幅为16.8 mm/10年。(2)秋季降水具有明显年代际变化特征,20世纪70年代初及中后期干旱少雨,80年代前期转入多雨年份,后期至2000年又进入干旱少雨时段,2001年以后旱涝交替变化频繁。(3)拉尼娜年份秋季易出现严重秋涝,连阴雨出现次数多,持续时间较长,对农作物的成熟收获有一定的影响。

The precipitation data of Zhengning National Meteorological Station from 1971 to 2020 were used to analyze the climatic characteristics of precipitation in autumn(September to November)in Zhengning County.The results showed that:(1)the autumn precipitation in Zhengning County showed a slightly increasing trend in recent 50 years,with an increase of 16.8 mm/10 a.(2)Autumn precipitation has obvious interdecadal variation characteristics,with drought and little rainfall in the early 1970s and the middle and late 1970s,turning into a rainy year in the early 1980s,and then entering a dry and little rainfall period in the late 2000,and frequent alternating changes of drought and flood after 2001.(3)In La Nina years,severe autumn waterlogging is easy to occur in autumn,and continuous rain occurs frequently and lasts for a long time,which has a certain impact on the maturity and harvest of crops.