The Last Glacial Maximum climate over Europe and western Siberia: a PMIP comparison between models and data

Under the framework of the Palaeoclimate Modelling Intercomparison Project (PMIP), 17 climate models, 16 of which are atmospheric general circulation models, have been run to simulate the climate of the Last Glacial Maximum ( 21 000 years ago) using the same set of boundary conditions. Parallel to th ese numerical experiments, new, consistent, data bases have been developed on a continental scale. The present work compares the range of the model re sponses to the large perturbation corresponding to the conditions of the La st Glacial Maximum with consistently derived climate reconstructions from p ollen records over Europe and western Siberia. It accounts for the differen ces in the model results due to the models themselves and directly compares this "error bar" due to the models to the uncertainties in the climate rec onstructions from the pollen records. Overall the Last Glacial Maximum clim ate simulated by the models over western Europe is warmer, especially in wi nter, and wetter than the one depicted by the reconstructions. This is the region where the reconstructed increase in temperature, precipitation and m oisture index from the Last Glacial Maximum to the present conditions is la rgest. The same disagreement, but of smaller amplitude, is found over Centr al Europe and the eastern Mediterranean Basin, while models and data are in broad agreement over western Siberia. The numerous modelling results allow a study of the link between the changes in atmospheric circulation and tho se in temperature, and an interpretation of the discrepancies in precipitat ion in terms of those in temperature.