Simulated Long-Term Vegetation-Climate Feedbacks in the Tibetan Plateau

The Tibetan Plateau (TP) is an important region of land-atmosphere interactions with high climate variability. In this study, an atmosphere-vegetation interaction model was applied to explore the possible responses of vegetation to climate warming, and to assess the impacts of land cover change on the land surface physical processes across the TP. Results showed that long-term warming over the TP could influence vegetation growth via different mechanisms. Most likely, increased temperature would enhance the physiological activity in most high cold areas on the TP, whereas high temperature would inhibit vegetation growth by increasing respiration in areas with favorable water and temperature conditions. In addition, for areas where the climate is warmer but not wetter, higher temperature could influence photosynthesis via the moisture condition of the vegetation rather than by modulating respiration. Numerical simulations demonstrated that vegetation could control the land surface-atmosphere energy balance effectively. The change of land cover from vegetated land to desert steppe decreased the net radiation absorbed by the surface, weakening the surface thermal effects, and reducing sensible and latent heat fluxes. Furthermore, sensitivity simulations also revealed that global warming would likely accelerate vegetation growth in most areas of the TP, resulting in increased surface heat flux.