Irminger Sea Is the Center of Action for Subpolar AMOC Variability
Irminger Sea Is the Center of Action for Subpolar AMOC Variability
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DOI：
10.1029/2022gl099133
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发表时间：
2022-09-16
影响因子：
5.2
通讯作者：
Rossby, T.
中科院分区：
文献类型：
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作者：
Chafik, L.;Holliday, N. P.;Rossby, T.
在高纬度地区，大西洋经向翻转环流（AMOC）的强度变化可能会造成重大的社会气候影响。关注亚极地北大西洋（SPNA）的变化和长期变化-一个关键的AMOC行动中心-并使用东部OSNAP阵列观测，我们确定了Irminger海（2014-2018）AMOC强度的明显密度和海面高度特征，并通过海洋再分析（1993-2018）进行了加强和扩展。使用Irminger海密度重建AMOC变率显示了北大西洋涛动对多个时间尺度上的副极地翻转的强大控制，通过拉布拉多海的环流和沃茨实现。此外，自20世纪中期（1950-2019年）以来，观察到的Irminger海密度下降表明长期AMOC减弱2.2 Sv或13%，然而，由于SPNA的年际和年代际变化较大，这种趋势在统计上仍然不显著。
Significant societally important climate impacts can be caused by changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) at higher latitudes. Focusing on variability and long-term change of the subpolar North Atlantic (SPNA)-a key AMOC action center-and using eastern OSNAP array observations, we identify a distinct density and sea-surface height signature of the AMOC strength in the Irminger Sea (2014-2018), reinforced and extended with an ocean reanalysis (1993-2018). Reconstruction of AMOC variability using Irminger Sea density shows strong control by the North Atlantic Oscillation on subpolar overturning on multiple timescales, achieved via the gyre circulation and waters from the Labrador Sea. Furthermore, the observed decrease of Irminger Sea density since the mid-twentieth century (1950-2019) is suggestive of a long-term AMOC weakening of 2.2 Sv or 13%, however, this trend remains statistically insignificant due to the large interannual and decadal variability of the SPNA.