ABSTRACT
The topography of the Tibetan Plateau (TP) has shaped the paleoclimatic evolution of the Asian monsoon. However, the influence of the TP on the global climate, beyond the domain of the Asian monsoon, remains unclear. Here we show that the Pacific and Atlantic Oceans act as efficient repeaters that boost the global climatic impact of the TP. The simulations demonstrate that oceanic repeaters enable TP heating to induce a wide-ranging climate response across the globe. A 1 °C TP warming can result in a 0.73 °C temperature increase over North America. Oceanic repeaters exert their influence by enhancing the air-sea interaction-mediated horizontal heat and moisture transport, as well as relevant atmospheric circulation pathways including westerlies, stationary waves, and zonal-vertical cells. Air-sea interactions were further tied to local feedbacks, mainly the decreased air-sea latent heat flux from the weakening air-sea humidity difference and the increased shortwave radiation from sinking motion-induced cloud reduction over the North Pacific and Atlantic Oceans. Our findings highlight the crucial influence of TP heating variation on the current climate under a quasi-fixed topography, in contrast to topography change previously studied in paleoclimate evolution. Therefore, TP heating should be considered in research on global climate change.
ABSTRACT
In the recent decade, hiatus is the hottest issue in the community of climate change. As the area of great importance, the Tibetan Plateau (TP), however, did not appear to have any warming stoppage in the hiatus period. In fact, the TP showed a continuous warming in the recent decade. To explore why the TP did not show hiatus, we divide the surface air temperature into dynamically-induced temperature (DIT) and radiatively-forced temperature (RFT) by applying the dynamical adjustment method. Our results show that DIT displayed a relatively uniform warming background in the TP, with no obvious correlations with dynamic factors. Meanwhile, as the major contribution to warming, the RFT effect over the TP played the dominant role. The warming role is illustrated using the temperature change between perturbed and control simulation responses to CO2 or black carbon (BC) forcing via Community Earth System Model (CESM). It shows that an obvious warming in the TP is induced by the CO2 warming effect, and BC exhibits an amplifying effect on the warming. Therefore, the continuous warming in the TP was a result of uniform DIT warming over a large scale and enhanced RFT warming at a regional scale.
