Multi-year sea-ice conditions in the western Canadian Arctic Archipelago region of the Northwest Passage: 1968-2006

Numerous studies have reported decreases in Arctic sea-ice cover over the past several decades and General Circulation Model (GCM) simulations continue to predict future decreases. These decreases - particularly in thick perennial or multi-year ice (MYI) - have led to considerable speculation about a more accessible Northwest Passage (NWP) as a transit route through the Canadian Arctic Archipelago (CAA). The Canadian Ice Service Digital Archive (CISDA) is used to investigate dynamic import/export and in situ growth of MYI within the western CAA regions of the NWP from 1968 to 2006. This analysis finds that MYI conditions in the western CAA regions of the NWP have remained relatively stable because the M'Clintock Channel and Franklin regions continuously operate as a drain-trap mechanism for MYI. Results also show that in addition to the Queen Elizabeth Islands (QEI) region, the Western Parry Channel and the M'Clintock Channel are also regions where a considerable amount of MYI forms in situ and combined with dynamic imports contributes to heavy MYI conditions. There is also evidence to suggest that more frequent dynamic import of MYI appears to have occurred since-1999 compared to the formation of more MYI in situ before 1999. As a result, tire drain-trap mechanism that has historically maintained heavy MYI conditions in the NWP is perhaps operating faster now than it was in the past. Based on the 38-year MYI record examined in this study, it is likely that the mechanisms operating within the western CAA regions of the NWP can facilitate the continued presence of MYI for quite some time.