利用2008 -2020年青海省常规气象站和区域站逐小时降雨资料， 以及青海省洪涝灾情直报记录， 使用直接经济损失、 受灾总人数、 倒塌房屋数、 农业经济损失、 农业受灾面积等多种灾情要素以比值法构建灾损指数， 再利用百分位法将洪涝灾害划分为一般、 较重、 严重、 特重四个等级。分析不同等级洪涝灾害分布特征及差异性， 并与青海省降雨特征进行对比分析。综合利用主成分分析、 箱线图分析以及相关分析等方法， 探讨导致青海省洪涝灾害的主要降雨因子以及区域间的差异性特征。结果表明： 青海省洪涝灾害频发， 洪涝灾害所造成损失总体呈现加剧状态， 较重、 特重灾害在2016年后频次明显增多， 而每年7、 8月则是青海省洪涝灾害高发时期。洪涝灾害频发区域和受灾最为严重区域均位于青海省东部， 其中海南州是洪涝灾害最为频发区域， 海东市是灾害损失最严重区域。诱发青海省洪涝灾害的降雨过程主要为大雨以上降雨。青海省致洪降雨过程可分为两类， 第一类降雨过程历时短但雨强大， 造成累积降雨量较大， 降雨历时在12 h内。第二类为降雨过程历时较长造成累积雨量较大， 这类降雨历时超过12 h。诱发青海省东部城市洪涝灾害的降雨过程以第一类为主， 多发于青海省东部城市海南、 黄南、 海北、 西宁和海东（黄南、 海北、 西宁和海东等地也有第二类致洪降雨过程）， 致洪降雨强度明显高于其他地区； 第二类致洪降雨多出现在海西州和玉树州等地。降雨过程中累积降雨量和24 h降雨量同洪涝灾害造成的损失有着紧密联系， 较长的降雨历时则会进一步加剧洪涝灾害损失。

Using observed hourly precipitation data and disaster records of flooding in Qinghai， we adopt the ratio weight method to construct the disaster index of flood disaster events based on the direct economic loss， disaster-affected population， collapsed houses， agricultural economic loss and agricultural disaster area.According to the percentile method， flood disasters are graded into general， heavy， severe， and extra heavy.The disaster distribution characteristics and differences of the four ranks are analyzed and compared with the precipitation characteristics in Qinghai.Principal component analysis， box-whisker plot and correlation analysis are employed to investigate the main factors that lead to flood disasters in Qinghai and the differences among regions.Results show that flood disasters occur frequently， and losses caused by floods increase.The frequency of severe and extra heavy disasters increases significantly after 2016， and the periods of July and August are the most frequent periods of flood disasters in Qinghai every year.The eastern part of Qinghai is an area of frequent floods and the most serious disasters.The Hainan Prefecture has the most flooding frequency and the Haidong City suffers the most serious disaster losses.The flooding disasters in Qinghai are mainly induced by rainfall processes that are more serious than heavy rainfall.The process of flood-causing precipitation in Qinghai can divide into two categories， one is short-lived but has a high rainfall intensity， which has a rainfall duration of 12 h and can cause high accumulated precipitation.The other can also induce high accumulated precipitation， and its rainfall duration is generally longer than 12 h.The flood disasters occurring in eastern cities like Hainan， Huangnan， Haibei， Xining and Haidong are mainly induced by the first category of precipitation process mentioned above.The second category of rainfall process is mainly found in Haixi and Yushu Prefecture， and Huangnan， Haibei， Xining and Haidong are also affected by this precipitation process.The accumulated precipitation and 24 h precipitation are closely associated with flood disaster losses， and longer precipitation duration can further aggravate flood disaster losses.