1961-2019年新疆暴雨山洪灾害损失的时空变化特征

Temporal and Spatial Variation Characteristics of Rainstorm Torrential Flood Disaster Loss in Xinjiang during 1961-2019

利用1961—2019年新疆86县(市)暴雨山洪灾害的5个灾情要素数据(死亡人数、倒塌房屋数、倒塌棚圈数、牲畜死亡数量、农作物受灾面积),采用比值权重法和无量纲化线性求和方法构建暴雨山洪灾害灾损指数,根据灾损指数的不同阈值范围将暴雨山洪灾害定量划分等级,并分析其时空分布特征。结果表明:(1)新疆暴雨山洪灾害主要出现在伊犁州、阿克苏地区和喀什地区,其中伊犁州伊宁县、巩留县、霍城县和尼勒克县最重,伊犁州暴雨山洪的致灾危险性与其暴雨日数分布有很好的一致性。(2)新疆暴雨山洪灾害发生具有很强的季节性,在夏季6—8月危害性最大,其中灾害出现次数和死亡人数均在7月最多(与降水相关性最大)。(3)近59 a来新疆暴雨山洪灾害的强度呈上升趋势,年灾损指数随时间呈线性增长趋势,暴雨山洪灾害的强度在20世纪80年代中期明显增加,其年际变化与3—10月降水量、大雨日数、暴雨日数密切相关。

Based on 5 disaster factors(the death toll,the number of collapsed houses,the number of collapsed sheds,the number of livestock deaths,and the crops affected area of rainstorm torrential flood disaster)of 86 counties(cities)in Xinjiang from 1961 to 2019,we used the ratio weighting method and the linear dimensionless method to construct the rainstorm torrential flood disaster loss index.According to the different threshold ranges of the disaster loss index,we quantitatively classified the rainstorm torrential flood disaster and analyzed their temporal and spatial variation characteristics.The results are as follows.(1)The rainstorm torrential flood disasters in Xinjiang mainly occurred in Ili,Aksu and Kashgar region.Ili Prefecture(Yining County,Gongliu County,Huocheng County and Nileke County)are the heaviest rainstorm torrential flood disaster areas.The disaster risk of rainstorm torrential flood in Ili Prefecture is consistent with the distribution of rainstorm days.(2)The occurrence of rainstorm mountain flood disasters has a strong seasonality in Xinjian,with the greatest harm from June to August in summer,in which the number of disasters and the number of deaths are the highest in July(which has the greatest correlation with precipitation).(3)The intensity of rainstorm torrential flood disasters in Xinjiang has been on the rise during 1961-2019,and the annual damage index has a linear increasing trend with time.The intensity of rainstorm torrential flood disasters increased significantly in the mid-1980s,and its interannual variation was closely related to the precipitation,the number of heavy rain days and the number of heavy rain days from March to October.