RESPONSE OF THE AFRICAN MONSOON TO ORBITAL FORCING AND OCEAN FEEDBACKS IN THE MIDDLE HOLOCENE

Simulations with a climate model that asynchronously couples the atmos phere and the ocean showed that the increased amplitude of the seasona l cycle oi insolation in the Northern Hemisphere 6000 years ago could have increased tropical Atlantic sea surface temperatures in late summ er. The simulated increase in sea surface temperature and associated c hanges in atmospheric circulation enhanced the summer monsoon precipit ation of northern Africa by more than 25 percent, compared with the mi ddle Holocene simulation with prescribed modern sea surface temperatur es, and provided better agreement with paleorecords of enhanced monsoo ns.