辽宁省泥石流与不同时间尺度下降水因子的关系研究

The Relationship Between Debris Flow and Water Factor in Different Time Scales in Liaoning Province

辽宁省地处中国北方降水性泥石流多发地带,收集了辽宁省1980—2019年由强降水引发的386起泥石流统计资料,采用GIS空间分析、统计分析等方法,探究该省泥石流与不同时间尺度降水因子的关系,同时研究短期内不同有效降水阈值对泥石流发生概率的影响。结果表明:长时间尺度上,泥石流频次与雨季降水量、年暴雨雨量、年大暴雨日数的线性关系最强,与其他降水因子线性关系不明显。泥石流频次与短期有效降水量的相关程度由高到低依次为当日有效降水量、前3 d累计有效降水量、前7 d累计有效降水量。不同前期有效降水阈值下,泥石流发生概率不同,当日有效降水量达50 mm、前3 d累计有效降水量达到77mm或前7 d累计有效降水量达142 mm,有50%的概率会发生泥石流。泥石流风险预测要综合考虑地形地貌与下垫面物质等地理环境特征。

Liaoning province is located in the northern China drop water mudslides in multiple area,collected in liaoning province in 1980-2019 statistical data 386 landslides triggered by heavy rain,the methods of GIS spatial analysis,statistical analysis,to explore the province debris flow with different time scale factor,the relationship between rainfall and study different effective rainfall in the short term threshold effect on the occurrence probability of debris flow.The results show that in the long time scale,the frequency of debris flow has the strongest linear relationship with the precipitation in rainy season,the annual rainstorm rainfall,and the number of heavy rainstorm days,but has no obvious linear relationship with other precipitation factors.The correlation degree between debris flow frequency and short-term effective precipitation from high to low is the daily effective precipitation,the accumulated effective precipitation in the first 3 days,and the accumulated effective precipitation in the first 7 days.Under different thresholds of effective precipitation in the early stage,the occurrence probability of debris flow is different.When the effective precipitation on the day reaches 50 mm,the accumulated effective precipitation in the first 3 days reaches 77mm,or the accumulated effective precipitation in the first 7 days reaches 142 mm,there is a 50%probability of debris flow.The risk prediction of debris flow should take into account the geographical environment characteristics such as landform and underlying surface material.