Atmospheric response to changes in Arctic sea ice thickness
Experiments with an atmospheric GCM are used to determine the effect of anomalous Arctic sea ice thickness on the atmospheric circulation. Ice thickness data are taken from a hindcast simulation with an ocean-sea ice model under NCAR/NCEP forcing. Ice conditions from 1964–1966 and 1994–1996 represent extreme cases of largest and smallest ice volume, respectively, during the last 50 years. The atmospheric response to the 1990s thinning of Arctic sea ice comprises a reduction in sea level pressure in the central Arctic and over the Nordic Seas. High pressure anomalies evolve over the subtropical North Atlantic and over the subpolar North Pacific. Similar signals occur at 500 hPa. Realistic sea ice thickness changes can induce atmospheric signals that are of similar magnitude as those due to changes in sea ice cover.