基于1961—2019年新疆86个县（市）出现的3220次暴雨洪涝灾害事件,依据灾害中出现的死亡人数、倒塌房屋数、倒塌棚圈数、牲畜死亡数量和农作物受灾面积5种灾情要素构建灾损指数,并根据百分位数方法对灾损指数进行等级划分,对应将暴雨洪涝灾害事件定量划分为一般、较重、严重、特重4个等级,用于评估新疆暴雨洪涝灾害的时空分布及其变化。新疆出现暴雨洪涝灾害次数最多的区域是伊犁河谷、阿克苏地区和喀什地区,同时这3个区域也是出现暴雨洪涝灾情最重的区域。危害性等级较轻（一般、较重）的暴雨洪涝灾害出现次数较多的区域大多集中在新疆北部,随着暴雨洪涝灾害危害程度加重,新疆北部大部分区域严重和特重等级灾害出现次数迅速减少,新疆南部的阿克苏、喀什等地区平均出现次数明显多于全疆其他区域,伊犁河谷各危害性等级出现次数较其他区域为中等到较多,尤其是特重等级暴雨洪涝灾害出现次数位居全疆前三。新疆暴雨洪涝灾害主要出现在夏季,6月和7月出现次数最多。新疆暴雨洪涝灾害出现次数的突变出现在1980年代中期,自1980年代中期起,新疆3—10月降水增多,极端降水事件增加,各危险等级暴雨洪涝灾害出现次数、年出现次数和年灾损指数发生了3.8~5.6倍的增幅;降水量和大雨以上量级的降水日数是形成新疆暴雨洪涝灾害的主要致灾因子。

In this paper, the rainstorm flood damage index was used to evaluate a rainstorm flood disaster in Xinjiang, China from 1961 to 2019, and the temporal and spatial variation characteristics of different grades of rainstorm flood disasters were analyzed. Accordingly, the main disaster factors of rainstorm flood disasters in Xinjiang were determined. Based on 3220 rainstorm flood events in 86 counties (cities) of Xinjiang from 1961 to 2019, a disaster loss index for rainstorm flood disaster events was constructed on the basis of the number of deaths caused by each rainstorm flood disaster, the number of collapsed houses, the number of collapsed sheds, the number of livestock deaths, and the affected area, as disaster factors. According to different threshold ranges of the disaster loss index, each rainstorm flood disaster event was divided into four grades—general, heavy, serious, or severe-and used to evaluate rainstorm flood disasters of varying intensity in Xinjiang from 1961 to 2019. The areas with the most frequent rainstorms and flood disasters were found to be the Ili River Valley, the Aksu Prefecture, and the Kashi Prefecture, and these three areas also experienced the most severe rainstorm and flood disasters. Most of the areas with more frequent occurrence of less harmful (general, heavy) events were concentrated in northern Xinjiang. With the increase in hazard levels, the number of and serious rainstorm flood disasters in most areas of northern Xinjiang decreased rapidly. The average number of events in areas in southern Xinjiang, such as the Aksu Prefecture and Kashi Prefecture, was obviously more than that in other regions of Xinjiang. The number of events of each hazard grade in the Ili River Valley has been moderate to high to other regions, although the number of heavy-grade events has sharply risen. The Ili River Valley has the greatest annual precipitation of any region in Xinjiang. The frequency of short-term heavy precipitation in the Aksu and Kashi regions is also high, providing a material basis for rainstorm flood disasters. The heavy rain and flood disasters in Xinjiang mostly occur in summer, with the most common months being June and July. The pattern is the same regarding the precipitation, the number of days above the heavy rain threshold, and the maximum number of days above the heavy rain threshold. In the mid-1980s, there was a sudden change in the occurrence of rainstorm flood disasters in Xinjiang. Since then, precipitation in Xinjiang from March-October has increased, and extreme precipitation events have also increased. There have also been increases of 3.8-5.6 times in the number of occurrences, annual occurrences, and the annual disaster loss index of rainstorm and flood disasters at each dangerous grade. Precipitation and precipitation days above the heavy rain threshold are the main disaster factors in Xinjiang rainstorm flood disasters. These research results can provide a technical basis for the risk assessment of rainstorm and flood disaster factors and for natural disaster risk regionalization in Xinjiang. At the same time, this study of extreme precipitation events also provides direction for future research on the mechanism of rainstorms and flood disasters in Xinjiang.