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青海东部暴雨过程特征及灾害风险评估方法研究

Study of rainstorm events characteristics and disaster risk assessment method in eastern Qinghai

  • 摘要: 为评估青海东部人口稠密区的暴雨灾害风险程度,提升暴雨灾害防御能力,基于1961—2021年青海东部25个国家气象观测站逐日降雨资料,首先采用百分位法确定单站极端日降水阈值,并分析暴雨过程特征,然后结合地理信息、遥感和社会经济数据,利用暴雨灾害风险评估技术、熵权法和专家打分法构建暴雨灾害风险评估模型,最后利用2022—2024年的暴雨过程实际灾情进行了检验。结果表明:(1) 1961—2021年,青海东部暴雨过程次数、日最大降雨量、过程累计降雨量、过程持续时间均呈增加趋势;(2)青海东部地区暴雨过程强度指数总体呈增加趋势,并在东北部以及南部存在两个高值区;(3)青海东部暴雨灾害风险总体呈东北高、西部低的分布,其中西宁市、大通县、湟源县、湟中区、门源县、互助县、乐都区、民和县为暴雨灾害的高风险区;(4)检验结果显示,发生灾情的乡镇72.04%出现在高和较高风险区,仅13.17%出现在暴雨灾害风险较低和低风险区,暴雨灾害风险评估模型较好地评估青海东部暴雨天气致灾的情况。

     

    Abstract: This study aim to assess the risk of rainstorm disasters and enhance the ability to prevent rainstorm disasters in the densely-populated areas of eastern Qinghai. Based on the daily precipitation data of 25 national meteorological stations in eastern Qinghai , firstly, the extreme daily precipitation threshold was identified by the percentile method, the rainstorm event characteristics from 1961 to 2021 was analyzed. Then, the rainstorm disaster risk assessment model was constructed used the rainstorm disaster risk assessmen technology combined with geographic information, remote sensing and socioeconomic data, and model factor weight coefficient was caculated by entropy weight method. Finally, the actual disaster conditions of rainstorm events in 2022-2024 were used for evaluation and verification. The results are as follows. (1) From 1961 to 2021, the number of rainstorm events, daily maximum precipitation, events cumulative precipitation, and event duration in eastern Qinghai all showed an increasing trend. (2) The intensity index of rainstorm events in eastern Qinghai shows an overall increasing trend, with peaks occurring in the northeast and south. (3) The rainstorm disaster risks in eastern Qinghai is high in the northeast and low in the west. Among them, the Xining urban area, Datong County, Huangyuan County, Huangzhong District, Menyuan County, Huzhu County, Ledu District and Minhe County are high-risk areas. (4) 72.04% of the townships with disaster conditions appeared in high-risk areas, and only 13.17% appeared in low-risk areas of rainstorm disaster risks. The rainstorm disaster risk assessment model well reflected the disaster situation caused by rainstorms in eastern Qinghai.

     

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