基于GIS的安徽省江淮分水岭区域气象干旱研究

Research of Meteorological Drought in Jianghuai Watershed Area of Anhui Province Based on GIS

为了解江淮分水岭地区的气象干旱情况,利用30年逐日降水数据,根据信息熵理论,计算了均态尺度和变化尺度下的标准降水指数,并进行叠加分析,统计了30年间逐日干湿等级事件数量,从而分析了江淮分水岭地区干旱发生的时空变化特点。结果表明:(1)在两种尺度叠加情况下,江淮分水岭地区"特别干"和"特别湿"等级事件缺失,干湿等级事件总体呈正态分布,越趋向极端的干湿等级事件发生的概率越小,其中,"正常"事件发生的概率均在50%以上,其他事件发生的概率均小于20%;(2)各月份中西部地区气象干旱日数占比较高,春季、冬季干事件主要发生在南部,夏秋季节干事件主要发生在西部;(3)从干湿等级发生区域来看,西部、南部易发生"轻微干"事件,西部易发生"严重干"事件。可为江淮分水岭地区的防灾减灾提供一定的科学依据。

In order to understand the conditions of meteorological drought in Jianghuai Watershed Area,using the daily precipitation data of 30 years and according to the information entropy theory,we calculated the standard precipitation index based on the homogeneous state intrinsic scale and variational state intrinsic scale.The results showed that in the case of superposition of two scales,the level event of especially wet and special dry is missing in Jianghuai Watershed Area;the overall level of dry and wet events normally distributes.The more extremely the level of wet and dry tended to,the smaller the probability of events happened.The probability of the normal events is over 50% and other event probability is less than 20%.In each month,the midwest area accounts for a higher share of days of meteorological drought in Jianghuai Watershed Area.The southern area is the main area of dry event occurrence in the spring and winter.And the westward area is the main area of dry event occurrence in summer.From the point of dry and wet level area,lightly dry event is easy to occur in the western and southern areas,and the western area is prone to severely dry events.These results can provide scientific basis fro research on meteorological drought for disaster prevention and mitigation in Jianghuai watershed area.