Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany.
MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
Sci Rep. 2016 Sep 13;6:32881. doi: 10.1038/srep32881.
As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962-1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models.
作为大气动力学的一个关键持久组成部分，北大西洋阻塞活动与欧洲地区的极端气候现象有关。它也与大西洋多年代际海洋变率有关，但尚未研究其与快速海洋变化的潜在联系。利用一个由大气再分析数据驱动的全球海洋-海冰模式，本研究表明，1962-1966 年期间格陵兰上空增强的阻塞活动导致北极地区海冰异常积累，并最终通过弗拉姆海峡从北极涌入北大西洋。这一事件导致拉布拉多海海水表面盐度显著降低，北大西洋经向翻转环流（AMOC）在 20 世纪 70 年代突然减弱。这些结果对快速 AMOC 变化的预测具有重要意义，并表明中高纬度地区的大气-海洋动力的一个重要部分需要对弗拉姆海峡海冰输送和大气阻塞等天气尺度变化进行适当的表示，这是当前耦合气候模型面临的挑战。
