Progresses in Studies of Elevation Dependence on Surface Warming over Tibetan Plateau

Tibetan Plateau has an average elevation of 4000 meters,due to the complex terrain and its special geographical location,so it has a great influence on global climate change and has become a hot topic and key areas of the study.Paleoclimate proxies,meteorological stations and data derived from the satellite show that TP has experienced significant warming.Monthly mean minimum temperature increase is most significant compared to the maximum,especially in winter.The air temperature increases with altitude.Meanwhile,outputs of different general community models also show the obvious elevation dependency under current and future climate change scenarios.Outputs of GCMs show that snow-albedo and cloud-radiation feedbacks may be responsible for the elevation dependency.However,the routine observation stations are scarce above 5000 m a.s.l.on Tibetan Plateau and it is difficult to obtain continuous meteorological data.The reliability of GCM prediction is still low owing partly to the coarse spatial resolution of models and partly to the land surface processes in complex topographic areas like the TP.This makes our understanding of elevation-dependent climate remains challenging.Therefore,there exists two problems about elevation dependency of warming.Firstly,how to obtain observations and model data of higher elevations and use as much as obwervation datas to support and validate the problem of altitude dependence,such as above 6000 m a.s.l..secondly,if there is an elevation-dependent climate,how to explain the physical mechanisms about the altitude dependence of climate warming over Tibetan Plateau.