Abstract: Using daily sea ice concentration data from satellites (AMSR-E and AMSR2), the average sea ice area from July to September (2002–2018) in the Canadian Arctic Archipelago was calculated and the average sea ice variation in September was studied. Based on the ice-breaking capacity of a merchant ship, the threshold of sea ice concentration was determined. Key areas of the Northwest Passage were selected for study with the navigable windows counted and the possibility of actual commercial navigation discussed. We found that sea ice areas of the Canadian Arctic Archipelago in July, August and September showed a downward trend over the past 17 years with clear fluctuations. The interannual variations in September sea ice distribution were complex. In the navigable years for the Northwest Passage, the navigable start date was generally in August and the end date varied from the end of September to the beginning of October; the navigable duration was more than 14 days with the longest reaching 80 days. In general, Northwest Passage navigable years and duration lacked regularity.

Key words: Canadian Arctic Archipelago, sea ice variability, Northwest Passage, Arctic shipping