Comparison of Arctic sea ice thickness variability in IPCC Climate of the 20th Century experiments and in ocean -: sea ice hindcasts

[ 1] Arctic sea ice is an important climate component and often regarded as an early indicator of anthropogenic global change. For an assessment of coupled climate models, their performance with respect to the development of Arctic sea ice thickness during the 20th century is examined. Their behavior is compared with results from an ocean - sea ice model using the Arctic Ocean Model Intercomparison Project (AOMIP) atmospheric forcing for the period 1948 - 2000. In lieu of actually observed sea ice thickness, this model result under realistic atmospheric forcing serves as a benchmark for the coupled climate models. The hindcast exhibits virtually no trend in Arctic ice volume over its integration period 1948 - 2000. Most of the coupled climate models show a negative trend over the 20th century that accelerates towards the end of that century.