气候系统模式对Hadley环流的模拟和未来变化预估

Simulation and Projection of Hadley Circulation in Coupled Climate Models

针对全球变暖背景下未来Hadley环流将如何变化这一问题,评估了气候系统模式对1970～1999年Hadley环流时空特征的模拟效能,并在此基础上选取能合理模拟Hadley环流空间结构、强度指数和边界指数变化的3个模式,通过多模式集合方法预估了未来Hadley环流在A1B排放情景下的可能演变。预估结果表明,在全球变暖背景下,相比于1970～1999年,到本世纪末期(2070～2099年),北半球Hadley环流在4个季节都将减弱,春季变化幅度相对较弱;南半球Hadley环流在冬季和夏季也会减弱,而在春季和秋季的变化不明显。另外,北半球Hadley环流的北边界除在夏季向南收缩外,在其它3个季节均向北伸展;南半球Had-ley环流的南边界在4个季节均向极地方向移动。两个半球的Hadley环流在垂直方向还将向对流层上层伸展。

In order to address the possible change of the Hadley circulation in response to global warming in the future, the ability of coupled climate models in simulating the temporal and spatial features of Hadley circulation is assessed by a comparison with the observation during 1970 - 1999. On this basis, three models which can well re- produce the spatial structure and the temporal change of the intensity and expansion of Hadley circulation are select- ed as the ensemble to project its possible change under the AIB scenario. The projection results show that the Northern Hemispheric Hadley circulation tends to weaken in four seasons but with weaker change in spring during the late 21st century （2070 - 2099） as compared to the period 1970 - 1979. The Southern Hemispheric Hadley cir- culation will also weaken in winter and summer, while its change in spring and autumn is not significant. In addi- tion, except a southward shift in summer, the Hadley circulation in the Northern Hemisphere will exhibit a north- ward expansion in the other three seasons during the late 21st century. The Hadley circulation in the Southern Hem- isphere will move poleward in all seasons. Moreover, the upward shift of the Hadley circulation in the vertical may appear in both hemispheres in a warmer climate.