Propagation and Transformation of Upper North Atlantic Deep Water From the Subpolar Gyre to 26.5°N

被引:7
作者
Petit, T. [1 ,2 ]
Lozier, M. S. [1 ]
Ruehs, S. [3 ,4 ]
Handmann, P. [3 ]
Biastoch, A. [3 ,5 ]
机构
[1] Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA
[2] Univ Reading, Natl Ctr Atmospher Sci, Dept Meteorol, Reading, England
[3] GEOMAR Helmholtz Ctr Ocean Res Kiel, Kiel, Germany
[4] Univ Utrecht, Inst Marine & Atmospher Res Utrecht, Utrecht, Netherlands
[5] Univ Kiel, Kiel, Germany
基金
美国国家科学基金会;
关键词
LABRADOR SEA-WATER; MERIDIONAL OVERTURNING CIRCULATION; WESTERN BOUNDARY CURRENT; INTERIOR PATHWAYS; HEAT; TRANSPORT; CURRENTS; IMPACT;
D O I
10.1029/2023JC019726
中图分类号
P7 [海洋学];
学科分类号
0707 ;
摘要
Because new observations have revealed that the Labrador Sea is not the primary source for waters in the lower limb of the Atlantic Meridional Overturning Circulation (AMOC) during the Overturning in the Subpolar North Atlantic Programme (OSNAP) period, it seems timely to re-examine the traditional interpretation of pathways and property variability for the AMOC lower limb from the subpolar gyre to 26.5 degrees N. In order to better understand these connections, Lagrangian experiments were conducted within an eddy-rich ocean model to track upper North Atlantic Deep Water (uNADW), defined by density, between the OSNAP line and 26.5 degrees N as well as within the Labrador Sea. The experiments reveal that 77% of uNADW at 26.5 degrees N is directly advected from the OSNAP West section along the boundary current and interior pathways west of the Mid-Atlantic Ridge. More precisely, the Labrador Sea is a main gateway for uNADW sourced from the Irminger Sea, while particles connecting OSNAP East to 26.5 degrees N are exclusively advected from the Iceland Basin and Rockall Trough along the eastern flank of the Mid-Atlantic Ridge. Although the pathways between OSNAP West and 26.5 degrees N are only associated with a net formation of 1.1 Sv into the uNADW layer, they show large density changes within the layer. Similarly, as the particles transit through the Labrador Sea, they undergo substantial freshening and cooling that contributes to further densification within the uNADW layer.
引用
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页数:13
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