In summer 2018, thick sea ice blocked the mouth of the Amundsen Gulf (AG), Canada, obstructing shipping through the North-west Passage. This study analysed multi-year ice motion to investigate the source of this thick ice and the reasons for its unusual movement. For this purpose, a daily multi-year ice distribution product was generated by ice tracking using gridded daily sea-ice velocities (2003–2018) derived from the AMSR-E and AMSR-2 data. From autumn 2017 to summer 2018, the area of multi-year ice extended westward to the Beaufort Sea and then migrated towards the AG mouth. The primary cause of the unusual ice cover was anomalous AG-ward wind in September 2018. It is known that multi-year ice has become increasingly moveable over the past decades, as indicated by the increasing wind factor (i.e., ratio of ice-drift speed and wind speed), but the unusual ice motion in the summer of 2018 cannot be explainable by the wind factor alone. Accurately, predicting monthly wind and monitoring old thick ice will reduce the risk posed by thick Arctic sea ice to shipping.

2018年夏季，浓厚的海冰阻塞了加拿大阿蒙森湾（AG）的河口，阻碍了西北通道的运输。这项研究分析了多年的冰运动，以调查这种厚冰的来源及其异常运动的原因。为此，使用从AMSR-E和AMSR-2数据得出的网格化海冰每日速度（2003-2018），通过冰跟踪来生成每日多年的冰分布产品。从2017年秋季到2018年夏季，多年的冰区向西延伸至Beaufort海，然后向AG口迁移。异常冰盖的主要原因是2018年9月AG向风异常。众所周知，在过去的几十年中，多年的冰层变得越来越可移动，这可以通过风速因子（即，冰漂移的比例）的增加来表明。速度和风速），但是2018年夏季的异常冰运动不能仅凭风速因素来解释。准确地，预测每月的风向并监测旧的厚冰将减少北极厚厚的海冰对运输造成的风险。