关键词: 青藏高原, Hadley环流, 经向热量输送

Abstract:

The impact of Tibetan Plateau on the global atmospheric temperature and water vapor distribution is studied using a fully coupled climate model CESM. Comprasion of the sensitivity test without the Tibetan topography (NoTibet) and the reference experiment of realistic topography (Real) shows that the northern hemisphere becomes cold and dry in NoTibet, the southern hemisphere is much the same. Specifically, in the high latitudes of the northern hemisphere, there is a strong cooling from the surface to the stratosphere. The surface cooling centre is in the North Atlantic ocean where the mean annual temperature falls by 5ºC. Another cooling centre is at the 100 hPa which falls by 2ºC. The humidity decreases in the North Atlantic and South Asia, but increases in the South Atlantic and East Africa. Due to the reduction of ocean meridional heat transport, the meridional poleward temperature gradient strengthens, leading to the enhancement of the Hadley circulation. Then it enhances atmospheric meridional heat transport, partly compensates for the depressed northward ocean heat transport, and maintains energy balance in the mid-low latitudes of the northern hemisphere; on the other hand, the humidity reduces in the mid-high latitudes, the northern hemisphere becomes cold and dry. The study shows that Tibetan Plateau has a significant impact on the climate in the northern hemisphere, the sphere of influence can reach to the high latitude.

Key words: Tibetan Plateau, Hadley circulation, meridional heat transport