Exploring the Arctic Ocean under Arctic amplification

摘要

Rate of surface air temperature increase in the Arctic is roughly twice that of the global average,and this phenomenon is referred to as“Arctic Amplification”(Serreze and Barry,2011).The Arctic sea ice season(October to September)of 2017–2018 is the second warmest in Arctic since 1900(Overland et al.,2018);2014–2018 are the five warmest years in the Arctic since 1900(Overland et al.,2018).Mean temperatures in Finland,Norway,and Svalbard in May 2018 are the highest in the instrumental record since the early 1900s(NOAA,2018),and the extensive warm spells over Scandinavia led to extensive forest fires(Overland et al.,2018).Arctic sea ice extent has decreased considerably mostly as a result of atmospheric and ocean warming.Sea ice decline is present in all months,and is the highest in September with a rate of 12.8%per decade since 1979(Fetterer et al.,2017).The oldest ice,defined as ice that is more than 4 years old,is also normally the thickest ice.The percentage of the oldest ice in the March has reduced by 95%between 1985 and 2018(Perovich et al.,2018).Thus,compared with 1979–2018 climatology,the Arctic Ocean in the ice season of 2017–2018 was dominated by much younger and thinner ice(Perovich et al.,2018).The oldest and thickest sea ice of the Arctic Ocean generally remains in the region between the Canadian Arctic Archipelago,Greenland,and the North Pole(Lindsay and Schweiger,2015).Thus,the unprecedented polynyas that appeared in this region during winter 2017–2018 would promote further reduction of multi-year ice(Moore et al.,2018).