Study on the Spatiotemporal Variations of Rainfall Warning Risks on China's Conventional Non-Highspeed Railways under the Background of Climate Warming

Abstract

Abstract China’s complex terrain and diverse rainfall patterns contribute to uneven and distinctive precipitation distribution. Over 70% of disasters and accidents on conventional non-highspeed railways in China are influenced by rainfall. This paper analyzes the spatiotemporal variations of rainfall warning risk on conventional non-highspeed railways in China and explores the impact of changing rainfall patterns on the safety and operational order of these railways in the context of climate warming. The study reveals the following findings: (1) Both annual total precipitation and the risk hours of railway rainfall warnings exhibit an east-west and south-north spatial distribution, with more precipitation in the east and south, and fewer in the west and north. Southern China experiences the highest precipitation levels and the most intense rainfall, while northern and northeastern regions have the highest risk hours for railway inspections. Sichuan and Yunnan show the highest occurrences 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 northward and the subtropical high extends westward, July becomes the peak month for railway rainfall warning risk hours in the Northeast, Central North, and Southwest regions. In August, the impact of typhoon-induced heavy rainfall leads to the peak in railway closure rainfall warning risk hours in the Southeast. (3) In comparison, the complex terrain of the Southwest region results in a significantly higher comprehensive risk index for railway rainfall than other regions, making it the area with the greatest railway rainfall warning pressure. The Northeast region, with lower annual total precipitation, exhibits the highest frequency index for railway rainfall warning risk, implying a relatively strict preventive approach. The Southeast region, with the highest annual total precipitation, has a comprehensive risk index second only to the Southwest region, indicating slightly lower prevention pressure. (4) Against the backdrop of climate warming, the Southwest region experiences a significant increase in conventional non-highspeed railway precipitation 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.