The Tibetan Plateau (TP) has experienced accelerated warming in recent decades, especially in winter. However, a comprehensive quantitative study of its long-term warming processes during daytime and nighttime is lacking. This study quantifies the different processes driving the acceleration of winter daytime and nighttime warming over the TP during 1961-2022 using surface energy budget analysis. The results show that the surface warming over the TP is mainly controlled by two processes: (a) a decrease in snow cover leading to a decrease in albedo and an increase in net downward shortwave radiation (snow-albedo feedback), and (b) a warming in tropospheric temperature (850 - 200 hPa) leading to an increase in downward longwave radiation (air warming-longwave radiation effect). The latter has a greater impact on the spatial distribution of warming than the former, and both factors jointly influence the elevation dependent warming pattern. Snow-albedo feedback is the primary factor in daytime warming over the monsoon region, contributing to about 59% of the simulated warming trend. In contrast, nighttime warming over the monsoon region and daytime/nighttime warming in the westerly region are primarily caused by the air warming-longwave radiation effect, contributing up to 67% of the simulated warming trend. The trend in the near-surface temperature mirrors that of the surface temperature, and the same process can explain changes in both. However, there are some differences: an increase in sensible heat flux is driven by a rise in the ground-atmosphere temperature difference. The increase in latent heat flux is associated with enhanced evaporation due to increased soil temperature and is also controlled by soil moisture. Both of these processes regulate the temperature difference between ground and near-surface atmosphere.

The spring snow-albedo feedback (SAF) has been found to be positively correlated with summer drying in the United States in climate change simulations. However, whether this relationship exists in real climate is unclear. In this letter, we explored the relationship between spring SAF and summer drying with the help of satellite observations. It was found that a positive correlation between spring SAF and summer drying existed from 1982 to 2013. There was a negative interannual correlation between spring SAF strength and summer soil moisture (SM) (r 0.35) throughout dry regions in western North America, Europe, and central Asia. Furthermore, the strength of the snow-cover component (-0.67 +/- 0.06% . K-1, effect of T-s on land surface albedo (a(s)) over surfaces transitioning from snow-covered to snow-free conditions) was about twice the magnitude of the metamorphosis component (-0.31 +/- 0.07% . K-1, effect of T-s on a(s) over snow-covered surfaces) during the spring, which explained the majority of spring SAF strength over the Northern Hemisphere (NH) snow-covered landmass during 1982-2013. Meanwhile, the sensitivity of summer SM and T-s to changes in the snow-cover component rather than the meta-morphosis component dominated the relationship between spring SAF and summer drying over the NH. This was the first attempt to provide observational evidence for the sensitivity of summer drying to spring SAF over the NH.