Study of the Spatiotemporal Variations of Rainfall Warning Risks of Conventional Non-highspeed Railways in China

Abstract

China’s complex terrain and diverse rainfall patterns contribute to uneven and distinctiverainfall distributions. Over 70% of disasters and accidents on conventional non-highspeed railways in China are influenced by rainfall. This paper analyses the spatiotemporal variations in rainfall warning risk on conventional non-highspeed railways in China. The study reveals the following findings: (1) Both the annual total rainfall and the risk hours of railway rainfall warnings exhibit east–west and south–north spatial distributions, with more rainfall in East China and South China and less rainfall in West China and North China. Southern China experiences the highest rainfall levels and the most intense rainfall, whereas the northern and northeastern regions have the highest risk hours for railway inspections. Sichuan and Yunnan have the highest occurrence rates of railway speed restrictions and closures. (2) The peak locations and periods of railway rainfall warning risk hours in various regions are closely related to the main monsoon rain belt and typhoon activities in China. Influenced by the East Asian summer monsoon, the Southeast Region experiences the earliest peak (June) in railway inspection and speed restriction rainfall warning risk hours. As the main rain belt of the monsoon moves northwards and the subtropical high extends westwards, July becomes the peak month for warning of railway rainfall risk hours in the Northeast, Central North, and Southwest Regions. In August, the impact of typhoon-induced heavy rainfall leads to a peak in railway closure rainfall warning risk hours in Southeast China. (3) In comparison, the complex terrain of the Southwest region results in a significantly higher comprehensive risk index for railway rainfall than other regions do, making it the area with the greatest railway rainfall warning pressure. The Northeast Region, with lower annual total rainfall, presents the highest frequency index for railway rainfall warning risk, implying a relatively strict preventive approach. The Southeast Region, with the highest annual total rainfall, has a comprehensive risk index second only to the Southwest Region, indicating slightly lower prevention pressure. (4) Over the past decade, the Southwest region experiences a significant increase in conventional non-highspeed railway rainfall volume, frequency, and comprehensive risk index during the main rainy season. Considering the complex terrain and frequent seismic activity in this region, it is likely to be a critical focus for future railway rainfall warning efforts.