Accession Number : ADP007268

Title :   Detection of Temperature and Sea Ice Extent Changes in the Antarctic and Southern Ocean,

Corporate Author : MELBOURNE UNIV PARKVILLE (AUSTRALIA)

Personal Author(s) : Jacka, T. H. ; Budd, W. F.

Report Date : MAR 1992

Pagination or Media Count : 8

Abstract : Some global climate models indicate that future global warning from increased atmospheric concentrations of greenhouse gases may be greatest in the polar regions, over areas where the sea ice cover is reduced. The reduction of sea ice area in the models also gives rise to a strong positive feedback to the warming. From the increase of atmospheric greenhouse gas concentration to date and the results of transient climate models, an estimate of the expected change in the Antarctic temperatures and sea ice extent can be made. The existing data for observed changes in temperatures of the Antarctic and Southern Ocean (extending back to approx. 1956 and approx. 1945 respectively) are analyzed along with the data of sea ice cover (commencing in 1973) to examine the extent to which the anticipated warming trends and sea ice decrease are being realized. In spite of high temporal and spatial variability, the data does support small significant trends of temperature increase and sea ice cover decrease compatible in magnitude to those expected as a consequence of atmospheric greenhouse gas increase. The seasonal cycle shows a delayed period of autumn-winter sea ice growth with a longer period of open water. This supports a mechanism for positive feedback between decreasing sea ice cover and increasing temperature.

Descriptors :   *CLIMATE, *POLAR REGIONS, *SEA ICE, *TEMPERATURE, ATMOSPHERICS, CYCLES, ESTIMATES, FEEDBACK, GLOBAL, GREENHOUSE EFFECT, ICE MECHANICS, MODELS, OCEANS, OPEN WATER, OCEANS, TRANSIENTS, WATER, ANTARCTIC REGIONS, ENVIRONMENTAL IMPACT.

Subject Categories : Meteorology
      Snow, Ice and Permafrost

Distribution Statement : APPROVED FOR PUBLIC RELEASE