Climate sensitivity to the mean state of sea ice

• Main Authors: Cecilia Bitz, Marika Holland
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.492.728; http://www-pcmdi.llnl.gov/projects/cmip/cmip_subprojects/Bitz/bitz_proposal.pdf

How sensitive are projections of greenhouse warming to the mean state of the sea ice? According to a study by Rind et al. (1997), thickness rather than the extent of sea ice in the Northern Hemisphere is the key parameter affecting the climate sensitivity controlled by sea ice. In contrast, they find that ice extent dominates in the Southern Hemisphere. Their study was conducted with the GISS climate model tuned to achieve a variety of different initial conditions. We propose to repeat and expand upon their analysis with an across-model study of the climate sensitivity relating the simulated sea ice in the CMIP2 models. We will intercompare the CO2 induced increase in global temperature and its latitudinal dependence with the mean state of the sea ice under present day conditions. We will focus on sea ice behavior including the spatial distribution and hemispheric mean thickness and coverage. Background Summaries of the results of CMIP models in chapters 8 and 9 of the IPCC (2001) and our own analysis of CMIP2 models that are archived by the IPCC DDC indicate that present day sea ice extent explains little of their climate sensitivity. For example, the simulated sea