An inversion method for air to land surface temperature considering different slope orientations in a high-altitude permafrost region

The general surface temperature is influenced by changes in air temperature and is affected by local factors. The Tibetan Plateau, characterized by its high altitude and intense solar radiation, shows substantial effects related to slope orientation. Slope orientation plays a crucial role in controlling the absorption and reflection of solar radiation, leading to variations in surface temperatures across various slope orientations and complicating the relationship between surface and air temperatures. This study focused on air temperature and slope orientation. Considering atmospheric parameters such as solar altitude angle (h), solar declination angle (δ), hour angle (ψ), and local geographical parameters like latitude and longitude. We proposed a novel method for estimating surface temperature on slopes based on air temperature, validated using measured data from the established octagonal platform at the Huashixia permafrost observation station in the Tibetan Plateau. Results indicated that at a significance level of P < 0.05, the highest correlation coefficient and linear fitting coefficient (R²) calculated using daily average air temperature were 0.89 and 0.79, respectively. When applying monthly average air temperature, these values were 0.99 and 0.98. This demonstrated that using monthly average air temperature as an inversion parameter yielded high-accuracy near-surface temperatures. The study will provide important guidance for optimizing design parameters and setting boundary conditions for stability prediction models for railways, highways, and other infrastructure under different orientations.