Seasonal changes in sea ice conditions along the Northeast Passage in 2007 and 2012

Remote sensing data from passive microwave and satellite-based altimeters, associated with the data measured underway, were used to characterize seasonal and spatial changes in sea ice conditions along the Arctic Northeast Passage （NEP） and the high-latitude sea route （HSR） north of the island groups in the eastern Arctic Ocean in 2007 and 2012. In both years, summer Arctic sea ice extent reached minima since satellite records began in 1979. However, there were large differences in spatial distribution of sea ice between the two years. Sea ice conditions in the eastern sections of the sea routes were relatively slight in the 2007 summer, because of the remarkable decline of sea ice in the Pacific sector. A belt of sea ice that blocked sections from the western Laptev Sea to the eastern Kara Sea resulted in both sea routes not completely opening through the 2007 summer. The combination of a great storm in early August causing sea ice to be sheared from the Arctic pack ice and the thick ice surviving the winter delayed the summer opening of the eastern parts of the sea routes in 2012. However, the average open period, defined by 50% ice concentration for the entire NEP and HSR, reached 82 d and 55 d, respectively. Thus, 2012 was the most accessible year since the satellite era began in 1979. The distinct decrease in sea ice in the western parts of the HSR in the 2012 summer can be attributed to the thinning preconditions of sea ice prior to the melt season. The HSR opening can benefit Arctic shipping of deeper-draft vessels.

Analysis of sea ice conditions and navigability in the Arctic Northeast Passage during the summer from 2002-2021

The decreasing of Arctic sea ice is projected to continue with global warming,which makes the summer navigation conditions of the Arctic improve.Based on the multi-source remote-sensing data with inter-sensor calibration processing and the ship-based observational data from R/V Xuelong and M/V Yongsheng,the sea ice conditions of the Arctic Northeast Passage(NEP)during the 2002-2021 summer seasons were analyzed,and the navigability of the NEP between July and October from 2002 to 2021 was discussed.Inter-sensor calibration could effectively reduce the deviation from different passive microwave data.Sea ice extent and thickness in the NEP decreased annually,which resulted in the navigability of the NEP showing a potential tendency toward improvement in navigability.The navigation period was mainly concentrated in early August to early October.The middle part of the NEP was primarily affected by sea ice.This influence decreased over time,while the navigation period increased,especially in the Vilkitsky Strait,which is a key shipping area.This analysis of sea ice conditions and navigability in the past 20 years could provide a reference for future scientific investigations and aid in merchant ship navigation in the Arctic summer.

Routeview:an intelligent route planning system for ships sailing through Arctic ice zones based on big Earth data

The potential of Arctic routes(ARs)has attracted global attention,and exploiting the Arctic has become an important strategy for many countries.However,there are still some challenges for ships sailing in Arctic ice zones,including harsh marine environments and the insufficient service capacity of sea ice information service systems.To better understand the route changes in the Arctic and extract real-time ship navigation routes,we developed an online interactive route planning system(RouteView)for ships sailing in the Arctic based on big Earth data.RouteView includes two main features:(1)an online calculation interface is provided for optimal routes along the Arctic Northeast Passage(NEP)60 days into the future by utilizing reinforcement learning(RL)based on sea ice and meteorological data,and(2)an online ice-water classification is established based on synthetic aperture radar(SAR)data and deep learning to help users extract the sea ice distribution in real time.This work can potentially enhance the safety of shipping navigation along the NEP and improve information extraction methods for ARs.