THE ANOMALOUS SEA-ICE EXTENT IN HUDSON-BAY, BAFFIN-BAY AND THE LABRADOR SEA DURING 3 SIMULTANEOUS NAO AND ENSO EPISODES

The nature of the sea-ice extent in Hudson Bay, Baffin Bay and the Lab rador Sea associated with the three strong simultaneous NAO (North Atl antic Oscillation) and ENSO (EI Nino-Southern Oscillation) episodes of 1972/73, 1982/83 and 1991/92 is investigated. During the first year o f the 1972/73 episode, when positive sea surface temperature (SST) ano malies occurred in the eastern tropical Pacific from January 1972 to F ebruary 1973 and the Icelandic Low substantially deepened in winter 19 73, there were heavy ice conditions (large positive sea-ice extent ano malies) in the study region and negative SST anomalies in the Labrador Sea and northwestern North Atlantic Ocean, north of 50 degrees N. The anomalous ice conditions are attributed to the coincident large-scale negative surface air temperature (SAT) and positive northerly wind an omalies in the region. Ten years later, during 1982/83, the strongest ENSO event of the past century occurred and extremely large positive s ea-ice extent anomalies persisted in the Baffin Bay-Labrador Sea regio n for almost two years. This response was also due to negative anomali es in the SAT for much of this period as well as very strong northerly winds in the Labrador Sea associated with a deepened Icelandic Low du ring autumn 1982 and winter 1983. During the winter of 1991/92, severe ice conditions were observed off Newfoundland in response to local ne gative SAT anomalies and a strong NAO event. Cross-correlations betwee n the regional SAT anomalies and the sea-ice area anomalies, as well a s the SO (Southern Oscillation) and NAO indices for the period 1953-90 , provide further support for the above findings.