1951—2020年中国南方地区低温雨雪冰冻危险性评估

Assessment of low temperature,rain/snow and freezing events of the southern China from 1951 to 2020

基于1951—2020年中国南方12个省(市、区)258个气象站的平均温度和降水量日数据,提取低温雨雪冰冻事件及其过程负积温、累积降水量及日最大降水量等指标,表征不同重现期下(5 a、10 a、30 a、50 a)的低温、雨雪、冰冻灾害危险性分布,再依据交通线路数据评估暴露风险。结果表明,发生次数较多地区集中在海拔较高的贵州、湖北、安徽、江苏等。平均持续时间的空间分布呈条带状,高值区边界较清晰,其中持续时间较长的区域在贵州和湖南。50 a一遇下的低温、雨雪、冰冻的负积温最低值为−78.2℃,累积降水量最大值为83.2 mm,日降水量最大值为38.9 mm。湖北、湖南、贵州、安徽及江西等地危险性较高,上述高危险区均存在高风险路段。

Due to cold waves,some regions of the southern China experience low or even extremely low temperatures in winter.When the temperature drops sharply,it may cause severe low temperatures,rain/snow and freezing disasters.These disasters seriously affect transportation,power safety,and other social production activities.This study used the precipitation and average temperature data from 258 stations in 12 provinces of the southern China between 1951 to 2020 to extract the low temperature events and screen the characteristic indexes,which were negative accumulated temperature,accumulated precipitation and daily maximum precipitation.The index values of different return periods(RP=5,10,30,50 a)were calculated to assess the hazard of low-temperature rain,snow,and freezing events accordingly.Combined with the distribution of highway and railway networks,the exposure of traffic lines was analyzed.The results showed that the areas with more events were concentrated in Guizhou,Hubei,Anhui,and Jiangsu.The duration was in a zonal distribution,and the boundaries of high-value areas were clear.Among them,the longer duration areas were in Guizhou and Hunan.The maximum value of negative accumulated temperature was−78.2℃,the maximum value of accumulated precipitation was 83.2 mm,and the maximum value of daily precipitation was 38.9 mm(RP=50 a).Hubei,Hunan,Guizhou,Anhui and Jiangxi were high risk areas,and the above-mentioned areas all had road sections with high risk.