Sensitivity of the Northern Hemisphere climate of the Last Glacial Maximumto sea surface temperatures

The role of prescribing sea surface temperature in paleoclimate atmospheric simulations has been investigated by comparing Last Glacial Maximum AGCMs experiments using different SSTs data sets as well as coupled atmosphere/oc eanic mixed layer models. Changes in the SSTs and sea-ice margin generate d ifferent patterns of zonal asymmetries in the atmospheric circulation that are responsible for reorganisation of heat and moisture transport, leading to important variations of Northern Hemisphere regional climates, particula rly in winter. Additional sensitivity experiments have been carried out to isolate the individual role of North Pacific and North Atlantic SSTs anomal ies. We found that changes in North Pacific SSTs have a much stronger impac t over all the northern continental surfaces, including Europe and Siberia, than changes in the North Atlantic SSTs. As these SSTs anomalies are of th e order of the typical errors generated by coupled ocean-atmosphere models, this suggests that these more complete models will likely still have probl ems in simulating the regional climate change at the LGM.