川藏铁路沿线大到暴雨时空演变特征

Temporal and Spatial Evolution Characteristics of Heavy Rain to Rainstorm along Sichuan-Tibet Railway

基于1980~2019年川藏铁路沿线13个地面观测站逐日降雨资料,应用经验正交函数分解、气候倾向率和小波分析等统计诊断方法,分析川藏铁路沿线大到暴雨的暴雨量与暴雨天数的时空变化特征。结果表明:川藏铁路沿线大到暴雨的各站逐年日数与累积暴雨量在空间分布上呈类似的空间分布,即铁路东段与中段西段的数值相对于其他区域是较大的;近40a川藏铁路沿线暴雨日与暴雨量的年际变化呈明显振荡特征,月际变化则显示6月至9月是暴雨频发的月份;川藏铁路沿线的暴雨日和暴雨量的EOF第一模态方差贡献率分别为37.39%和38.18%,即在空间变化上呈整体一致性;川藏铁路沿线暴雨量和暴雨日均存在4~6a和6~16a的振荡周期。

Based on the daily rainfall data of 13 ground observation stations along the Sichuan-Tibet Railway from 1980 to 2019, the spatiotemporal variation characteristics of heavy rainfall and heavy rainfall days along the Sichuan-Tibet Railway were analyzed by applying empirical orthogonal function decomposition, climate propensity rate and wavelet analysis and other statistical diagnostic methods. The results show that the number of days per year and the cumulative rainfall of each station along the Sichuan-Tibet Railway show a similar spatial distribution in terms of spatial distribution, that is, the values of the eastern section and the western section of the central section of the railway are larger than other regions. In the past 40a, the interannual variation of heavy rainfall days and heavy rainfall along the Sichuan-Tibet Railway showed obvious oscillation characteristics, and the intermonthly variation showed that June to September was a month with frequent heavy rainfall. The EOF first mode variance contribution rates of heavy rainfall days and heavy rainfall along the Sichuan-Tibet Railway were 37.39% and 38.18%, respectively, that is, the spatial variation was consistent as a whole. There are oscillation cycles of 4~6a and 6~16a along the Sichuan-Tibet Railway in heavy rainfall and heavy rainfall on a daily basis.