Kodaira Tsubasa, Waseda Takuji, Nose Takehiko, Inoue Jun
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
Arctic Environment Research Center, National Institute of Polar Research, Tachikawa, Japan.
Sci Rep. 2020 Nov 27;10(1):20830. doi: 10.1038/s41598-020-77488-y.
Arctic sea ice is rapidly decreasing during the recent period of global warming. One of the significant factors of the Arctic sea ice loss is oceanic heat transport from lower latitudes. For months of sea ice formation, the variations in the sea surface temperature over the Pacific Arctic region were highly correlated with the Pacific Decadal Oscillation (PDO). However, the seasonal sea surface temperatures recorded their highest values in autumn 2018 when the PDO index was neutral. It is shown that the anomalous warm seawater was a rapid ocean response to the southerly winds associated with episodic atmospheric blocking over the Bering Sea in September 2018. This warm seawater was directly observed by the R/V Mirai Arctic Expedition in November 2018 to significantly delay the southward sea ice advance. If the atmospheric blocking forms during the PDO positive phase in the future, the annual maximum Arctic sea ice extent could be dramatically reduced.
在近期全球变暖期间，北极海冰正在迅速减少。北极海冰流失的一个重要因素是来自低纬度地区的海洋热量输送。在海冰形成的几个月里，太平洋北极地区的海表温度变化与太平洋年代际振荡（PDO）高度相关。然而，季节性海表温度在2018年秋季达到最高值，当时PDO指数处于中性状态。结果表明，异常温暖的海水是对2018年9月白令海上空与偶发性大气阻塞相关的南风的快速海洋响应。2018年11月，“未来号”（R/V Mirai）北极考察直接观测到这种温暖的海水显著延迟了海冰向南推进。如果未来在PDO正相位期间形成大气阻塞，北极海冰年度最大范围可能会大幅减少。
