九龙县泥石流灾害与降水因子关系分析

Relationship Between Debris Flow Disaster and Precipitation Factors in Jiulong County

本文统计了九龙县降水引发的泥石流灾害个例与历史气象资料,分析小时雨强及当天、前7 d有效降水量等因子与泥石流灾害关系,得出结论:短时强降水引发泥石流灾害占3~4成;当小时降水量> 35 mm时或3 h累计有效降水量> 60 mm时,发生泥石流风险很高;泥石流发生当日降水量达大雨以上量级占比70.8%。泥石流发生概率与前期累计降水量呈指数增长关系。当前期有效降水量较大或有效降水量一般,但短时降水量较大时,发生泥石流风险增大。

Based on the statistics of debris flow disasters caused by precipitation in Jiulong County and historical meteorological data,this paper analyzes the relationship between the factors such as hourly rainfall intensity,effective precipitation of the day and the first seven days,and concludes that debris flow disaster caused by short-term heavy rainfall accounts for 30%~40%.When the hourly precipitation is more than 35mm or the accumulated effective precipitation is more than 60mm,the risk of debris flow is very high.The amount of precipitation on the day of debris flow was more than heavy rain,accounting for 77.4%.The probability of debris flow increases exponentially with the accumulated precipitation.When the early effective precipitation is large or the effective precipitation is general,but the short-term precipitation is large,the risk of debris flow increases.