Identification methods and trend analysis of navigable network in Arctic shipping routes

The trend of global climate change has increased the navigation potential of the Arctic shipping routes.Identifying the navigable passages and understanding the navigability trend of the routes is of great value to Arctic countries as well as to China.In this paper,based on the remote sensing data of Arctic Sea Ice Concentration（SIC） from China’s Fengyun-3 satellites（FY-3B/C/D） and Sea Ice Thickness（SIT） data from SMOS mission,a method for identifying navigable network is proposed based on image morphological algorithm,which is used to extract the daily navigable passages of the northeastern,northwestern and central Arctic shipping routes from 2011 to 2022.Moreover,the variation trend of navigable time window and the relative mileage are derived.Through the analysis of day-by-day navigable passages in the past 12 years,the results show that:1) The proposed identification method can effectively reduce the size of connectivity matrix,and improve the computational efficiency in identifying navigable sea ice channels by providing multiple alternative paths for route optimization;2) With 40% sea ice concentration and 0.5 m sea ice thickness as the navigable range threshold,the Arctic shipping routes have navigable time window for every year in the past 12 years.Among which,the Northeast Passage has the highest development value,and its navigable time window has a tendency to expand,but the starting and ending time of opening is still unstable;3) The Northwest Passage and the Arctic Central Route have more advantages than the Northeast Passage in terms of distance cost,and it is expected to shorten the voyage distance between the Atlantic and the Pacific Ocean if there were regular navigable time window in the future.