With the development of regional climate models, more realistic land cover changes (LCC) will improve simulation results. This paper uses two sets of land use data that are more accurate to create a vegetation function parameter set, design a sensitivity experiment, and use the latest RegCM5.0-CLM4.5 model to simulations. Compare the differences in LCC in different years and analyze the impact of LCC on regional climate. The results show that the new vegetation parameters improve the cold bias of the simulation results to a certain extent. The increase in vegetation coverage leads to a decrease in albedo, an increase in net radiation (Rn), and air temperatures (Ta) increase in the changing areas. The entire Qinghai-Tibet Plateau (QTP) is in a warming state, and the average LST increase can reach 0.10℃ (in 2000) and 0.36℃ (in 2020) respectively. The soil temperature (TS) can change as deep as 280cm, with obvious changes between 2cm and 100cm. The warming effect makes the thawing area of frozen soil increase and the freezing area decrease in the corresponding period. The snow amount in the western part of the plateau has decreased, with a change range of up to 5 kg m2. In the area where bare ground change to grassland, Rn, latent heat flux (LE), sensible heat flux (HS), and albedo (Alb) are the main factors affecting Ta (the correlation index: 0.76, 0.69, 0.69 and -0.83 respectively), and near-surface wind speed (NWS) and surface air density (SAD) are the main factors affecting LST (the correlation index: 0.63 and -0.39 respectively). In summary, the simulation results prove that plateau greening will cause an increase in LST and Ta. Under the action of soil heat conduction, it will advance the thawing period of frozen soil and delay the freezing period.
 

Qinghai-Tibet Plateau (QTP); land cover changes (LCC); RegCM