气象干旱综合监测指数在安徽省的适用性分析

Comparison of Comprehensive Meteorological Drought Index with Other Drought Indices and Its Applicability in Anhui Province

利用1981—2016年安徽省77站日降水量、平均气温和土壤墒情资料,通过相关分析和主成分分析方法构建了该区域旱季(10月至次年3月)、涝季(4-9月)气象干旱综合指数MCI_anhui,从频率分布、干旱日数演变、不合理跳跃次数及代表站典型干旱过程等方面,对4种气象干旱指数在安徽省的适用性展开对比分析。结果表明:MCI_anhui在反映较重等级气象干旱时优于其他指数,能很好地诊断出安徽历史上典型大旱年;基于该指数的干旱日数时空演变表现为沿淮北夏旱和春末旱最多,江淮之间春末夏初旱情最多,沿江江南秋旱最多;36年所有干旱过程中不合理跳跃次数不足10次,就典型干旱过程中对降水反应的敏感性而言,它在表现干旱缓慢发展的特征时优于其他指数,不合理波动较少,且干旱后期缓和或解除过程中也不如其他指数过于敏感。综合来看,MCI_anhui对干旱过程具有较好的识别与诊断能力,在安徽省适用性良好。

Based on the daily precipitation,temperature,and soil relative humidity data of 77 stations in Anhui Province from 1981 to 2016,the Gomprehensive Meteorological Drought Index（MCI_anhui）for dry season（October to March）and flood season（April to September）is constructed by using the correlation and principal component analysis methods.In respects of the frequency distribution,evolution of drought days,illogical jumping times and typical drought processes for representative stations,the applicability of four meteorological drought indices in Anhui is analyzed through contrasts.The results show that the MCI_anhuiis superior to others in reflecting the meteorological drought with heavier grades,which can well diagnose typical drought years in the history of Anhui.The number of drought days calculated from this index shows that droughts in the areas along and north of the Huaihe River occurred mostly in summer and late spring,while in the areas between Huaihe and Yangtze River,droughts mainly occurred in late spring and early summer,and in the areas along and south of the Yangtze River,droughts mainly occurred in autumn.The illogical jumping times of all drought processes in 36 years were less than 10.In terms of its sensitivity to precipitation during typical drought processes,it is represented that the MCI_anhui with less illogical jumping times is not only superior to others in reflecting slowly progressive characteristics of drought,but also less excessively sensitive during the later period of drought.In general,the MCI_anhuihas a better ability to identify and diagnose drought processes and favorable applicability in Anhui Province.