湖北省不同等级降水特征及其与旱涝的关系

Characteristics of Graded Precipitation and Its Relationship with Drought and Flood in Hubei Province

基于湖北省1961—2020年71个国家站逐日降水数据,利用降水异常指数Z和线性分析等方法,分析不同地区降水特征及与旱涝关系,结果表明:(1)湖北省年均降水自北向南递增,山区冬夏季雨日相当,降水量鄂西山区>鄂东山区>江汉平原>汉江河谷;(2)雨日随等级减小,大等级降水多发生于鄂东南。鄂西北暴雨占比最小,鄂西南各等级降水相当,江汉平原及以东地区中雨及以上量级降水贡献率较大;(3)年均雨日呈衰减趋势,降水量相反,而山地平原夏季雨日贡献率增加。小等级降水比例减小,年代际变化中降水日数呈减少趋势,而降水量“中间偏多,两端偏少”;(4)雨日对降水量的贡献率远高于降水强度。暴雨的距平变化可基本反映旱涝年。

Based on the daily precipitation data of 71 national stations in Hubei Province from 1961 to 2020,precipitation anomaly index Z and linear analysis were used to analyze the characteristics of precipitation in different regions and its relationship with drought and flood.The conclusions are as follows:(1)Annual average precipitation and precipitation days increase from north to south in Hubei Province.Precipitation days in winter and summer are almost the same in mountainous areas.The precipitation ranges from large to small in the mountainous areas of western Hubei,eastern Hubei,Jianghan Plain and Hanjiang Valley;(2)Precipitation days decrease with grades,and large-grade precipitation occurs in southeastern Hubei.The proportion of heavy rain is the smallest in northwest Hubei,and all grades of precipitation are similar in southwest Hubei.The Jianghan Plain and the area to the east have a large precipitation contribution rate of moderate rain and above;(3)Annual average precipitation days decrease while precipitation increase,but contribution rate of summer precipitation days increase in mountainous plains.The proportion of small-grade precipitation decreases.The precipitation days decrease,while precipitation in the middle decadal period is more than that in the decadal period at both ends in the interdecadal variation;(4)The contribution rate of precipitation days to precipitation is much higher than precipitation intensity.The anomaly changes of heavy rainfall can basically reflect the drought and flood years.