Coupled climate simulation of the evolution of global monsoons in the Holocene

Holocene climates are simulated under the insolation forcing at 3000, 6000, 8000, and 11000 years before present. The evolution of six major regional summer monsoons is investigated: the Asian monsoon, the North African monsoon, the North American monsoon, the Australian monsoon, the South American monsoon, and the South African monsoon.

Special attention has been paid to the relative roles of the direct insolation forcing and oceanic feedback. It is found that the responses of the monsoons to the insolation forcing and oceanic feedback differ substantially among regions, because of regional features of atmospheric and oceanic circulation and ocean-atmosphere interaction. In the Northern Hemisphere, the coupled models show a significant enhancement of all of the monsoons in the early Holocene and a gradual weakening toward the present, with the North African monsoon showing the largest relative changes.