A simulation of the Last Glacial Maximum with a coupled atmosphere‐ocean GCM

Abstract

A simulation of the Last Glacial Maximum (LGM) climate has been performed by a global coupled atmosphere‐ocean general circulation model (AOGCM). Two simulations are conducted for the LGM with different initial conditions: one with the present‐day initial condition and the other with a pre‐conditioning of fresh water flux over the North Atlantic. After more than 200 year integration both LGM simulations attained a similar quasi‐equilibrium state. The global mean surface air temperature dropped 3.9°C and precipitation decreased 11% compared to the present day simulation. The sea surface temperature dropped 1.7°C in the tropics, with larger decreases in the Atlantic than in the Indo‐Pacific. There is a region with warmer than present sea surface temperatures over the subtropical eastern Pacific. The thermohaline circulation in the North Atlantic in the LGM simulation is slightly stronger than in the present day simulation.