A vessel transit assessment of sea ice variability in the Western Arctic, 1969-2002: implications for ship navigation

Recent investigations have shown reduced sea ice extents in Arctic regions and subsequently suggested that the Northwest Passage (NWP) might be able to sustain a prolonged shipping season. To date, no scientific evidence has been presented, within a ship navigation framework, to support increased marine traffic. The Arctic Ice Regime Shipping System (AIRSS) ice numeral (IN), which controls shipping activity in Canadian Arctic waters, was spatially assimilated with the Canadian Ice Service (CIS) historical digital database utilizing a geographic information system (GIS). INs provide a quantifiable framework for examining historical ice states in the context of ship navigation. Results provide a spatial and temporal assessment of ship navigation variability, within a ship transit framework from 1969 to 2002 for the western portion of the NWP. Feasible routes through the NWP experience extreme interannual variability in INs over the past 34 years. Yearly fluctuations of the IN can be attributed to the frequency of multiyear ice (MYI) encounters. The western coast of Banks Island experienced lower INs since 1991 and may be a potential barrier to completely navigating the NWP. Decreases in INs were also found to be associated with the positive signal of the arctic oscillation (AO) index. High-latitude MYI invasions into NWP shipping lanes appear be a major pitfall of future navigation routing in the face of climate warming.