Antarctic surface temperature change for the Last Glacial Maximum (LGM) reproduced in the second phase of the Paleoclimate Modelling Intercomparison Program (PMIP2)

Abstract

The Antarctic surface temperature change for the Last Glacial Maximum (LGM) was investigated using the results of atmosphere-ocean-ice coupled models from the second phase of the Paleoclimate Modelling Intercomparison Program (PMIP2). In the analysis, we used seven models;the NCAR CCSM of USA,ECHAM3-MPIOM of German Max-Plank Institute, HadCM3M2 of UK Met Office, IPSL-CM4 of France Laplace Institute, CNRM-CM3 of France Meteorological Institute, MIROC3.2 of Japan CCSR at University of Tokyo, and FGOALS of China Institute of Atmospheric Physics. All seven models tend to underestimate the present Antarctic temperatures in comparison to the observed. In the LGM simulations, the atmospheric CO2 concentration and other greenhouse gases were reduced to the LGM level, the 5-G ice sheet reconstruction data were implemented,and orbital parameters of 21,000 years BP were used. With the implemented LGM conditions, the temperature over Antarctica has simulated about 8-12℃ below compared to the present in austral winter, while in summer it is 6-9℃ below. Overall, the annual mean surface temperature is about 7℃ below the present climate which is slightly lower than the temperature change obtained in the proxy evidence (about 10℃). The surface temperature reduction tends to bigger toward the high latitudes and biggest temperature reduction is found around the south pole. In austral winter, the surface temperature reduction is bigger around 65˚S than in 70˚S. This seems to be due to the increase in sea ice extent in the LGM in those latitudes.