ISSN 1003-8035 CN 11-2852/P

    基于降雨指数的台风暴雨型滑坡预警阈值研究以福州市永泰县为例

    Research on the early warning threshold for typhoon rainstorm-induced landslides based on rainfall index: A case study of Yongtai County, Fuzhou

    • 摘要: 我国东南丘陵地区极端降雨频繁,滑坡灾害多发、突发、群发,确定滑坡降雨预警阈值是区域防灾减灾工作的关键。基于前期有效降雨量和激发降雨量构建的经验性统计指标——降雨指数(R′),已被成功应用于日本广岛地区滑坡灾害的预警预报。福建沿海丘陵地区与日本广岛地区的孕灾环境十分相似,因此,以福州市永泰县为研究区,借鉴广岛的经验开展类似的研究具有重要的应用意义。通过统计分析“海葵”“尼伯特”典型台风暴雨型滑坡事件的历史降雨及灾情数据,确定降雨指数(R′)模型的关键参数,开展典型降雨过程和滑坡灾害点反演验证,提出适用于永泰县的降雨预警阈值。结果表明:(1)确定了前期有效降雨量基准值R1=120 mm、激发降雨量基准值r1=135 mm、降雨权重因子a=2.5及有效降雨折减系数α=0.85等R′模型的关键参数值;(2)提出R′=156 mm为永泰县台风暴雨型滑坡降雨预警阈值,该阈值可实现“尼伯特”台风降雨诱发滑坡的完全预警,也能对单点滑坡提前预警,推荐的提前预警时间为30 min。基于降雨指数(R′)模型及其确定的降雨阈值在永泰县台风暴雨型滑坡预警中显示出良好的适用性,该方法可供我国东南沿海类似地区的地质灾害气象预警借鉴。

       

      Abstract: In the southeastern hilly regions of China, extreme rainfall frequently triggers landslide disasters, characterized by their rapid occurrence and clustering. Establishing effective rainfall thresholds for early warning systems is crucial for regional disaster prevention and mitigation. The empirical rainfall index R′, which is based on antecedent effective rainfall and triggering rainfall, has been successfully utilized for early warnings and forecasting of landslide disasters in Hiroshima, Japan. Considering the strong similarities in disaster-prone environments between the coastal-hilly areas of Fujian Province and Hiroshima Prefecture, applying this methodology in Yongtai County, Fuzhou, is of significant practical value. This study involved statistical analysis of historical rainfall and disaster data from typical typhoon-induced rainstorm events, such as the Typhoons Haikui and Nepartak. Key parameters of the R′ model were established, and typical rainfall processes and landslide disaster points were analyzed for inverse verification, to propose a rainfall warning threshold suitable for Yongtai County. The results show that: 1) key parameters for the R′ model are determined, including the baseline values for antecedent rainfall (R1)=120 mm, triggering rainfall (r1)=135 mm, a rainfall weight factor (a)=2.5, and an effective rainfall reduction coefficient (α)=0.85. 2) a rainfall warning threshold of R′=156mm was proposed for typhoon rainstorm-induced landslides in Yongtai County. This threshold has proven effective in fully predicting landslides triggered triggered by Typhoon Nepartak, and it can also provide early warning for isolated landslide events, with a recommended lead time of 30 minutes. The rainfall index R′ model and its established threshold demonstrate excellent applicability for early warnings of typhoon rainstorm-induced landslides in Yongtai County, serving as a valuable reference for meteorological early warnings of geological disasters in similar coastal areas across southeastern China.

       

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