Fine-scale Simulation Study of Climate Characteristics along the Qinghai-Xizang Railway

Abstract

The Qinghai-Xizang Railway （QXR）， especially the 550-kilometer segment from Xidatan to Anduo， traverses a region characterized by complex terrain， diverse landforms， and a permafrost environment.In recent years， climate warming and permafrost degradation have significantly increased maintenance demands for the QXR， which is constructed atop permafrost.To understand the impacts of the intricate terrain and landforms along the QXR on local climate changes and to provide theoretical support for its operation and maintenance， this study utilizes station observation data along the railway and employs the Weather Research and Forecasting （WRF） model driven by ERA5 data to conduct high-resolution simulations with a grid resolution of 10 km×10 km.The results indicate that the six stations along the Qinghai-Xizang Railway exhibit a general warming trend from 1998 to 2020， with the lowest temperature increase rate at 0.27 ℃·（10a）-1 and the highest at 0.56 ℃·（10a）-1 years.The WRF model's simulation results show some discrepancies with observed annual mean temperature data.The simulation results are more accurate in summer and autumn， with correlation coefficients above 0.95 in summer and above 0.80 in autumn， but less accurate in spring and winter.Regarding precipitation simulation， the Nudging method effectively reduces the wet bias in summer precipitation on the Qinghai-Xizang Plateau.Precipitation gradually increases from the northern to the southern section of the railway， peaking in the central section.However， the WRF model still exhibits cold and wet biases in temperature and precipitation simulations on the Qinghai-Xizang Plateau.Exploring new methods or utilizing higher-quality driving data may further enhance the downscaled simulation results for this region.

Keywords

• qinghai-xizang railway
• wrf model
• dynamical downscaling
• fine-scale simulation
• temperature and precipitation