Changes in tropical atmospheric circulation and consequences during climate change.

Summary Variations in the large-scale tropical circulation during climate change may have important consequences in terms of impact on human activities. First, we study the tropical meridional circulation in different coupled climate models. During global warming, we find that the Hadley meridional circulations and subtropical jets are significantly shifted towards the poles, and that the intensity of these circulations decreases slightly during climate change. In a second part, simulations using the GCM LMDZ4 in different configurations, show that the intensity and displacement of Hadley cells are related to the uniform change in sea temperature but also to the change in meridional temperature gradients. Finally, we show that changes in Hadley circulation can then have a significant impact on water vapor feedback.