1.?Introduction . The Arctic—home to the coldest, shallowest, and smallest ocean in the world—is an important component of the global climate system. As a critical part of the Arctic ocean, sea ice significantly regulates the radiation, heat, and momentum exchange between the atmosphere and ocean, and impacts the mid-high latitude (e.g. Budikova 2009 , Honda et al2009 , Wu et al2009 , 2013 , 2015 , 2017 , Jaiser 2012 , Li and Wu 2012 , Liu et al2012 , Li and Wang...