Response of surface energy fluxes and hydrothermal characteristics to night-time precipitation changes in the southeastern Tibetan Plateau

This study aimed to evaluate the applicability of the land-surface model CLM 4.5 in the southeastern Tibetan Plateau by utilizing field observation data from Kabu and Pailong sites. Furthermore, the study investigated the impact of night-time precipitation changes on radiation, surface energy fluxes and soil hydrothermal characteristics in this region. Results revealed that CLM 4.5 accurately simulated upward shortwave/longwave radiation, surface energy fluxes and soil temperature in this region. However, the simulation of soil moisture exhibited a slight fluctuation of the simulated value during precipitation, resulting in poorer performance during heavy precipitation and a failure to simulate the rapid change of latent heat flux and soil moisture. Sensitivity experiments demonstrated that night-time precipitation significantly influenced upward shortwave/longwave radiation, energy budge and soil hydrothermal processes, with each element changing considerably with changes in precipitation. Surface energy fluxes and hydrothermal characteristics were found to be more sensitive to increased precipitation than decreased precipitation. Additionally, soil moisture was found to play a crucial role in the impact of precipitation changes on surface energy fluxes and hydrothermal characteristics. Furthermore, the study also found that changes in precipitation had a more pronounced effect on relatively dry areas and seasons than already extremely wet areas and seasons. Finally, the variation in soil moisture was found to be restricted by the original soil moisture. In conclusion, this study highlighted the significant influence of night-time precipitation on surface hydrothermal characteristics and surface energy budget in the southeastern Tibetan Plateau. Soil moisture was found to play a crucial role in the impact of precipitation changes on surface energy fluxes and hydrothermal characteristics, and changes in precipitation had a more pronounced effect on relatively dry areas and seasons.image