Accession Number : ADP007300

Title :   Greenland Sea Ice Anomalies During 1901-1984 and their Relation to an Interdecadal Arctic Climate Cycle,

Corporate Author : MCGILL UNIV MONTREAL (QUEBEC)

Personal Author(s) : Mysak, L. A. ; Manak, D. K. ; Marsden, R. K.

Report Date : MAR 1992

Pagination or Media Count : 6

Abstract : Two ice data sets from the Greenland and neighboring seas have been analyzed to determine interannual and decadal time scale sea ice extent anomalies during this century. Sea ice concentration data on a 1 deg x 1 deg grid for 1953-19 the presence of a large positive anomaly in the Greenland Sea during the 1960s which coincided with the Great Salinity Anomaly, a low-salinity water mass that traveled cyclonically around the northern North Atlantic during 1968-1982. The two anomalies propagated into the Labrador Sea with a typical travel time of 3-5 years. Spring and summer ice-limit data obtained from Danish Meteorological Institute charts for 1901-1956 indicated the presence of heavy ice conditions in the Greenland Sea during 1902-1920 and in the late, 1940s, and generally light ice conditions during the 1920s and 1930s. Only limited evidence of propagation of Greenland Sea ice anomalies into the Labrador Sea was observed, however. On the other hand, several large ice anomalies in the Greenland Sea occurred 2-3 years after large runoffs from northern Canada into the western Arctic Ocean. Similarly, a large runoff into the Arctic preceded the large Greenland Sea ice anomaly of the 1960s. These facts, together with recent evidence of climatic jumps in the Northern Hemisphere tropospheric circulation, suggest the existence of an interdecadal, self-sustained climate cycle in the Arctic which is described in terms of a negative feed-back loop. In the Greenland Sea this cycle is characterized by a state of large sea ice extent overlying a layer of cool freshwater that does not convectively overturn, which alternates with a state of small sea ice extent and warm saline surface water that frequently overturns.

Descriptors :   *CLIMATE, *ICE MECHANICS, *SEA ICE, ANOMALIES, ARCTIC OCEAN, CIRCULATION, CYCLES, GRIDS, NORTHERN HEMISPHERE, OCEANS, PROPAGATION, RUNOFF, SALINITY, SURFACE WATERS, TRAVEL TIME, WATER, GREENHOUSE EFFECT.

Subject Categories : Meteorology
      Snow, Ice and Permafrost

Distribution Statement : APPROVED FOR PUBLIC RELEASE