An Antarctic assessment of IPCC AR4 coupled models

We assess 19 coupled models from the IPCC fourth assessment report archive from the simulation of the 20th century, based on the calculation of ``skill scores.'' The models show a wide range of scores when assessed against Antarctic or global measures of large-scale circulation indices. Except for continental mass balance, the model average proves a more reliable estimate than that for any one model. Individual models show a very wide scatter in simulated Antarctic temperature trends over the past century; the large trend over the Antarctic peninsula in winter is not well represented, which makes it clear that whatever has been driving these trends is not well captured by many GCMs. Trends in temperature are clearly linked to the sea ice simulation, another variable that most models do not simulate well.