宁夏高等级公路强降雨时空分布特征及灾害风险评估

Temporal and Spatial Distribution Characteristics of Heavy Rainfall and Disaster Risk Assessment for Ningxia High-grade Highways

利用2011—2020年宁夏加密自动站逐时降雨资料,在统计、分析不同量级短时强降雨时空分布特征的基础上,采用气象资料、基础地理信息数据、交通及社会经济数据,从危险性、暴露度和脆弱性3个方面建立了宁夏高等级公路强降雨灾害风险评估指标集,并通过模糊综合评价法和层次分析法计算了评价因子和各指标权重,结合GIS空间分析法开展了宁夏高等级公路强降雨灾害风险评估。结果表明:(1)不同级别的短时强降雨其日变化均呈单峰型,午后至前半夜为短时强降雨多发时段,16:00为短时强降雨出现最多的时刻,后半夜至次日上午为短时强降雨低发时段;8月短时强降雨出现频次最多,其次为7月。(2)雨强≥10 mm/h,≥20 mm/h和≥30 mm/h的高频区主要分布在银川市西部和固原市东南部。其中固原市泾源县和彭阳县雨强≥10 mm/h,其强降雨年均发生频次为5~7次;银川市苏峪口一带和固原市彭阳县南部雨强≥20 mm/h,其强降雨年均发生频次超过2次;银川市金凤区西部及固原市彭阳县南部雨强≥30 mm/h,其强降雨年均发生频次超过1次。(3)宁夏高等级公路强降雨灾害高风险路段主要分布在福银高速和青兰高速固原市泾源段,较高风险路段位于福银高速固原市原州区南段和青兰高速固原市隆德段。

Based on hourly precipitation data of Ningxia Encrypted Automatic Station from 2011 to 2020,and statistical analysis of spatial and temporal characteristics of short-term heavy rainfalls with different magnitudes,this paper established the evaluation index set of heavy rainfall disasters on Ningxia high-grade highways from three aspects of risk,exposure and vulnerability by using meteorological data,basic geographic information data,and traffic and socioeconomic data.The evaluation factors and weights of each index were calculated by fuzzy comprehensive evaluation method and analytic hierarchy process,and the risk assessment of heavy rainfall disaster on Ningxia high-grade highways was carried out by combining GIS spatial analysis method.The results show that(1)the daily variation of short-term heavy rainfalls at different levels is unimodal.Afternoon to the first half of the night is the time when short-time heavy rainfalls are more frequent,during which 16:00 is the moment when the most short-time heavy rainfalls occur,and the second half of the night to the next morning is the time when short-time heavy rainfalls are few.It has the most frequent short-time heavy rainfalls in August,followed by July.(2)The high frequency regions of rainfall intensity≥10 mm/h,≥20 mm/h and≥30 mm/h are mainly distributed in the western part of Yinchuan and the southeastern part of Guyuan.The annual average frequency of rainfall≥10 mm/h in Jingyuan County and Pengyang County in the southern foothills of Liupan mountains is 5 to 7 times,that of rainfall≥20 mm/h in Suyukou area of Yinchuan and southern Pengyang County of Guyuan is more than twice,and that of rainfall≥30 mm/h in the western Jinfeng District of Yinchuan and the southern Pengyang County of Guyuan is more than one.(3)The high-risk sections of heavy rainfall disaster on Ningxia high-grade highways are mainly located in the Guyuan-Jingyuan section of Fuyin Expressway and Qinglan Expressway,while the relatively-high-risk sections are located in the southern section of Yuanzhou District of Fuyin Expressway and the Longde District of Qinglan Expressway.