The warming of Tibetan Plateau enhanced by 3D variation of low-level clouds during daytime

- We studied 3D cloud variations and their radiative effect during daytime in the TP.
- Low clouds fraction and geometrical depth reduced about 4.2% and 130 m.
- The surface shortwave radiation increases 29.7 W/m2 due to low clouds variations.
- We conclude that changes of low clouds significantly enhance the warming of the TP.

The Tibetan Plateau (TP) has experienced evident warming in recent decades, but the exact reasons for this warming remain unclear. In this study, we investigated the possible effect of the three-dimensional (3D) variations of cloud during daytime on climate warming over the TP from 2007 to 2015 based on CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. We found that the 3D changes occur mostly to low clouds, whose fraction and geometrical depth decrease by approximately 4.2% and 130 m, respectively. These changes result in the increase of the surface shortwave radiation (SSR) by approximately 29.7 W/m2, which is one magnitude larger than that of anthropogenic CO2. The increase in SSR leads to the increase in direct solar radiation absorption in the surface, which significantly enhances the warming of the TP.