成昆铁路(北段)汛期降水的时空统计特征及雨量警戒区段的划分

Spatial Statistical Characteristics of Precipitation in Flooding Season on Cheng-Kun Railway (North Section) and the Demarcation of Rainfall Alarm Zones

成昆铁路在四川境内穿越东南季风和西南季风两个季风气候区,降水水汽来源复杂;沿线地形差异大,地形对降水的形成和增幅作用有很大差别,因此,沿线的降水在时间和空间呈现出比较复杂的统计特征。在时间上主要表现为沿线全年降水的80%以上集中在5月～9月、夜雨率高、降水历时短、多暴雨性质降水等特征;在空间上表现为沿线水平分布不均、垂直差异大、局地暴雨突出等特征。"雨量警戒制度"是根据沿线的雨情来指导进行警戒,所以,警戒区段划分应充分考虑铁路沿线雨情特征,同时还应考虑到地面条件、线路状况和现场的操作与管理等因素。本文据此指导原则,以汛期降水量和汛期日降水量≥30mm的降水量作为划分指标,将成昆铁路的汛期雨量警戒区段划分为:双流—轸溪—甘洛—沙木拉打—小高—攀枝花。

The ChengKun railway goes through two seasonal wind zones in Sichuan province, the southeast seasonal wind and the southwest seasonal wind with a complicated rainfall source. The topographic conditions vary greatly along the line, which contributes greatly to the variation of assistance to the rainfall formation and its enhancement. Therefore, it is complicated to make a statistical analysis of the rainfall in time and spatial aspects. In the time aspect, over 80% of annual rainfall along the whole line falls during May through September, with heavy but short rainfall mostly at night. In the spatial aspect, the rainfall is not evenly distributed and varies greatly in vertical direction with outstanding storms in some local areas. ″The rainfall alarm system″ is practiced according to the rainfall conditions, along the line. So the distribution of the rainfall alarm zones should fully consider the rainfall conditions along the line and the surface conditions, track conditions,insitu operation and management. According to this principle, with the demarcation index of the precipitation in flooding season and the daily precipitation in the flooding season ≥30 mm, the Cheng-Kun railway flooding rainfall alarm zones are specified as Shuangliu-Zhenxi-Ganluo-Shamulada-Xiaogao-Panzhihua.