诱发滑坡的多尺度降雨特征  

Multi-Scale Rainfall Characteristics of Rainfall-Induced Landslides

作　　者：徐辉 刘海知 XU Hui;LIU Haizhi(National Meteorological Center,China Meteorological Administration,Beijing 100081,China)

机构地区：[1]国家气象中心,北京100081

出　　处：《山地学报》2019年第6期858-867,共10页Mountain Research

基　　金：国家重点研发计划(2017YFC1502501)。

摘　　要：在全球气候变暖背景下,极端性降水导致滑坡泥石流等自然灾害频发,关于降水与地质灾害之间的关系引起公众广泛的关注。本研究在对降水过程进行定量化划分的基础上研究滑坡发生与降水之间的关系,基于全国气象台站的地面降水观测资料,对2658例滑坡事件中的前期降水量、本场激发降水量、极端性降水量等不同时间尺度的降水特征进行了系统性的统计分析。结果表明:绝大部分的滑坡事件都属于前期有效降水主导型;前期降雨在导致滑坡的各个因素中占主导性地位;滑坡灾害发生前10 d特别是前5 d的降雨是导致滑坡发生的关键因素,而且降水产生时间与滑坡事件发生时间相隔越长,其在诱发滑坡事件发生的过程中的作用也越小;本场激发降雨是诱发滑坡事件发生重要的影响因素,持续时间大多集中在6 h之内,且以强度大、时间集中为特点的短时降水为主;极端性降水也是导致滑坡事件的关键诱发因素,大部分滑坡事件中的前15 d有效降水量和当日本场降水量在历史同期降水序列中均超过第90百分位数,具有明显的极端性特征。本研究从全国的视角来系统性地分析研究滑坡与降雨之间的关系,将为全国范围内的滑坡地质灾害预警提供参考。Under the background of global warming,geological disasters-including landslides and debris flows-are frequently triggered by extreme rainfall,and the relationship between rainfall and natural disasters has become a major scientific concern.This study reveals the relationship between landslide occurrence and rainfall based on a quantitative division of rainfall process.Based on surface rainfall records collected at national meteorological stations,the characteristics of rainfall at different time scales,which triggered 2658 landslides,were systematically analyzed.These characteristics was described as effective antecedent rainfall(EAR),induced rainfall,and extreme rainfall.The EAR was demonstrated to be the dominant factor for most landslides,suggesting that the effect of triggering rainfall related to landslides was weaker than that of EAR;However,the situation was quite different for debris flow formation,where the triggering rainfall process was dominant.The rainfall triggering debris flow occurrence was a result of induced rainfall of the same day.As for the rainfall process triggering landslides,the rainfall within the first six hours was an significant factor.Moreover,rainfall in the first 10-days before landslide disasters-especially the first 5-days-was the key factor leading to their occurrence.It was far easier for landslides to occur when the 15-day effective rainfall reaches 50~100 mm.The longer the time before landslide events occurred,the smaller the effect of rainfall on the motivation of landslide-induced events.The rainfall one day before the occurrence of a landslide event was the most significant factor inducing the landslide.Also,the triggering rainfall process was mainly short in duration but with high intensity.Short-duration with high volume of rainfall can generate a large area of surface confluence and surface runoff on slopes,resulting in slopes to be soaked and softened,which reduced the shear strength of slope soil and correspondingly increased pore water pressure,finally causing lands

关 键 词：滑坡 极端性降水 前期有效降水 本场激发雨量 

分 类 号：P426.62[天文地球—大气科学及气象学] P642.22