Abstract
Changing vegetation cover effect the land surface energy balance and frozen ground. Incorporating more accurate land cover changes (LCC) data can enhance simulation results. This paper used two sets of highly precise land use data from different time periods to establish a parameter set for plant functional types (PFTs) on Qinghai-Tibet Plateau (QTP) and employed the latest RegCM5.0-CLM4.5 model for sensitivity simulations, aiming to compare the differences in LCC in different years and analyze the impact of LCC on regional climate. The results showed that the realistic LCC significant effected frozen ground and land surface energy balance over the QTP. The entire QTP is in a warming state and the average land surface temperature(LST)increase can reach 0.10°C (in 2000) and 0.36°C (in 2020) respectively. The soil temperature (ST) can change as deep as 280cm, with obvious changes between 2cm and 100cm, which can get 0.07°C (in 2000) and 0.31°C (in 2020). The warming effect makes the thawing area of frozen ground increase in the thawing period and decrease in the freezing period. The correlations of various meteorological elements vary in different regions. The change of vegetation coverage leads to a decrease in albedo, an increase in net radiation (Rn) and air temperatures (Ta). The new PFTs improve the cold bias of the simulation Ta compared to the original PFTs. For the whole area, Rn and albedo (Alb) are the main factors affecting Ta (the correlation index: 0.69 and − 0.76 respectively). Near-surface wind speed (Nws), evaporation (Evp) and surface air density (Sad) are the main factors affecting LST (the correlation index: 0.28, -0.40 and − 0.41 respectively). In summary, the simulation results prove that plateau greening will cause an increase in LST, ST and Ta.