大连市作物生长季降水变化及农业旱涝程度分析

Precipitation Variation during the Crop Growing Season and Trend Analysis of Agricultural Drought and Flood in Dalian City in Recent 60 Years

[目的]研究近60年大连市作物生长季降水变化及农业旱涝程度。[方法]选取大连市观象台1951～2010年4～10月逐月降水量和平均气温资料,采用线性回归、气候倾向率和干湿指数等方法,仅从作物生长季自然降水趋势变化与农业需水满足程度方面,分析大连市近60年作物生长季降水变化和农业旱涝程度。[结果]近60年来,大连市作物生长季降水量呈下降趋势,倾向率为-15.888mm/10a,60年来降水量减少95.3 mm;春季降水略有增加,夏季明显减少,秋季减少幅度较小;各月平均降水量分布非常不均,7、8月降水量明显较多,共占作物生长季降水量的53.8%;4、5、10月平均降水量均低于作物生长季降水量的10.0%。近60年来大连市作物生长季内干湿指数K值平均为0.90,总体属于轻旱气候类型;干湿指数呈下降趋势,气候正朝着偏旱的方向发展;干旱发生频率为59%;春、秋季属于中旱气候类型,夏季总体属于偏湿气候类型;从历年平均看,除7、8月偏湿以上外,其他各月均达到中旱程度。[结论]该研究为地方农业生产、农业结构调整和旱涝灾害防御提供参考。

[Objective] The aim was to study the precipitation changes and agricultural flood and drought degree of crops in Dalian City in recent 60 years.[Method] The monthly precipitation and average temperature data from April to October during 1951-2010 in Dalian observation station were selected.By dint of linear regression,climate tendency rate and humidity index,the growth changes and agricultural flood and drought degree of crops in recent 60 years in Dalian City were expounded from the aspects of natural precipitation tendency changes and agricultural water satisfaction degree of crops in growth period.[Result] In recent 60 years,the precipitation of crops during growth period in Dalian City had decreasing tendency.The inclination rate was-15.888 m/10a.Precipitation decreased 95.3 mm in recent 60 years;precipitation increased a little in spring and decreased a lot in summer,then decreased in autumn.The monthly precipitation in each month distributed unevenly.Precipitation in July and August increased,taking account of 53.8% of the total precipitation during the growth period of crops.The K value of humidity index during the growth period of crops in Dalian in recent 60 years was 0.90 in general.It was light drought climate.The humidity index was decreasing.Climate developed toward drought direction;the drought occurrence frequency was 59%.It was mild drought climate in spring and autumn.The climate was generally wet in summer.Seen from the yearly means,besides of July and August,it reached mild drought degree in other months.[Conclusion] The study provided reference for the regional agricultural production,agricultural structure adjustment and drought and flood disaster prevention.