Paleoclimate modeling | Last glacial maximum gcms

General circulation models (GCMs) are valuable tools for developing a quantitative understanding of the dynamics of the climate of the Last Glacial Maximum (LGM). Common types of GCMs that have been used for this purpose include atmospheric GCMs, atmospheric GCMs coupled to simple ocean-mixed layer models, and coupled atmosphere-ocean GCMs. Simulations of the LGM are typically forced by imposing changes in atmospheric composition, Earth-Sun geometry, continental ice-sheet distribution, sea level, and vegetation. A number of interesting results have been reported from such modeling experiments, including larger cooling in the Northern Hemisphere, a northward diversion of the polar jet stream by the Laurentide ice sheet, a weakening of the South Asian summer monsoon, changes in the meridional overturning circulation, and changes in tropical Pacific climate variability.