JIANG Ying, CHEN Zhongyu, ZHANG Xiaomei, WANG Yuhong, GAO Jingjing, HU Ruoyu, ZHANG Hui, WU Hao
Complex topography along with unevenly distributed precipitation and changes in climate pattern make mountainous regions railway in China vulnerable to water-related geological hazards and rainfall-induced floods. This study investigates the impact of global warming on the safe operation of railways by analyzing the spatial and temporal variations of precipitation, changes in precipitation level distributions, and variations in the threshold hours for rainfall alert levels. The findings are as follows: (1) In recent years, there has been a significant decrease in annual precipitation in southern Jiangnan and south China, while there has been a significant increase in precipitation in the eastern parts of northwest and the northeastern parts of southwest. Management Areas of Guangzhou, Nanchang and Nanning Railway Bureaus have the highest annual precipitation which shows a decreasing trend, while areas of Zhengzhou, Jinan, and Xi'an Bureaus show an increasing trend in annual precipitation. The strong East Asian summer monsoon and the northward shift of the subtropical high are the main causes of precipitation changes. (2) Shenyang Bureau shows the most significant increase in precipitation intensity, while Nanning Bureau shows the most significant decrease. The changes in precipitation intensity are mainly related to variations in typhoons and short-duration heavy rainfall. (3) From the perspective of precipitation level distribution, in the past five years there has been a decrease in the frequency of heavy precipitation occurrence in bureaus such as Urumqi and Lanzhou in the northwest region, while there has been an increase in the frequency of heavy precipitation occurrence in bureaus such as Nanchang and Chengdu in the southwest to Jiangnan region. (4) Guangdong, Hainan, the eastern parts of the southwest region, and the northeastern parts of North China to the southeastern parts of Northeast China are the three high-value areas for railway alert hours due to precipitation. The high-value area for speed restriction hours has narrowed down to the eastern parts of the southwest region, and the high-value area for closure hours has further narrowed down. Overall, under the background of climate change, there has been a significant decrease in precipitation in southern Jiangnan and South China, leading to a reduction in rainfall hours and railway patrol hours, a slight decrease in speed restriction hours, and a decrease in the alert pressure for railway precipitation control. On the other hand, there has been a significant increase in railway patrol hours in the eastern parts of the southwest region to the northeastern parts of Northeast China, with a noticeable increase in speed restriction and closure hours in the eastern parts of the southwest region. This has resulted in an enhancement of alert pressure for railway precipitation control, with Chengdu Bureau showing a significant increase in patrol hours, speed restriction hours, and closure hours.
