Risk assessment of ice-class-based navigation in Arctic: a case study in the Vilkitsky Strait

Abstract Over the past four decades, the decrease in Arctic sea ice has driven significant growth in vessel traffic through the Arctic passages. A precise and quantitative sea ice risk assessment would be the cornerstone of route planning for Arctic ships. Taking the chokepoint of Arctic Northeast Passage, the Vilkitsky Strait, as an example, the temporal and spatial characteristics of ice conditions in the strait were analyzed based on simulated ice thickness and observed sea ice concentration data from 2012 to 2021. Additionally, navigation risk in the strait was assessed based on the Polar Operational Limit Assessment Risk Indexing System (POLARIS). The results showed that the strait experienced 100% sea ice coverage from December to May, peaking in thickness of nearly 2 m in May, receding starting in June, and presenting ice-free passages by August and September. A significant interannual variability is evident in the timing of sea ice melting and freezing. Moreover, the average navigability of the strait was 365 days for vessels with an ice class of PC3, 72 days for PC6 and fewer than 64 days for those below B1. Remarkably, in 2013, 2014, and 2021, vessels below PC5 had less than 30 navigable days in the strait.