NOAA/WDS Paleoclimatology - Crosta et al. 2004 Southern Ocean Diatom SST-Sea Ice Recons

A Modern Analog Technique (MAT5201/31) has been applied to fossil diatom assemblages to provide down-core
estimates of February sea-surface temperatures (SSTs) and of sea ice duration over the past 220 000 years at 56‡40PS,
160‡14PE. At the core location, sea ice progression lagged the SST drop by V1 ka at interglacial^glacial transitions,
and sea ice retreat was almost synchronous to the SST increase at glacial^interglacial terminations. Sea ice increased
continuously during glacial periods to reach its maximum extent at the end of glacial times, although SSTs were
almost constant during glacials. This indicates that SSTs are the major parameter determining the advance and retreat
of sea ice at transitions, but that the sea ice advance during glacial conditions may be related to positive feedbacks of
the ice on albedo, air temperature and meridional wind stress. The strong correlation (r =0.75) between sea ice
duration at the core location and the Vostok CO2 record argues for a control of Antarctic sea ice extent on
atmospheric CO2 concentration via the modification of the ocean-to-atmosphere gas balance.