Analysis of extreme rainfall scenarios and landslide susceptibility in the mountainous region of Phu Tho Province under the impacts of climate change

Tóm tắt

This study assesses the impacts of climate change on rainfall patterns and landslide risk in Cao Phong District, Phu Tho Province, with a particular focus on Bac Phong commune - a high-risk area. Climate data were bias-corrected from three regional climate models (PRECIS, CCAM, clWRF) under two emission scenarios (RCP4.5 and RCP8.5), using quantile mapping for statistical adjustment. Analyses for the periods 2016-2035, 2046-2065, and 2080-2099, relative to the baseline (1986-2005), reveal a pronounced increase in annual precipitation. Under RCP4.5, rainfall is projected to increase by +2.3% to +11.7%, while under RCP8.5, increases reach up to +12.5% by the end of the century. Rainfall during the wet season also rises substantially, by approximately +10.6-10.7%.
Extreme rainfall analysis indicates that about 82.5% of the district’s area is exposed to daily precipitation exceeding 270 mm - a threshold that triggers landslides in steep terrain with limited vegetation cover. Three rainfall-landslide hazard scenarios were developed: Low (P20), mean, and high (P80). Integrating these scenarios with topographic, geological, and land-use factors shows that areas of high and very high landslide susceptibility may account for more than 50% of the total area, concentrated mainly in the Southeastern part of the commune. The resulting landslide hazard zoning map provides an essential tool for early warning, climate-adapted planning, and disaster risk management in the context of climate change.