North Atlantic Deep Water and Climate Change

2009 ◽  
pp. 614-619
Author(s):  
Thomas M. Marchitto
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Deep Water ◽  
North Atlantic Deep Water

Identification and quantification of the North Atlantic Deep Water pathways

2021 ◽  
Author(s):  
Philippe Miron ◽  
Maria J. Olascoaga ◽  
Francisco J. Beron-Vera ◽  
Kimberly L. Drouin ◽  
M. Susan Lozier
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Sea Water ◽  
Lower Layer ◽  
North Atlantic Deep Water ◽  
Meridional Overturning Circulation ◽  
Labrador Sea ◽  
Western Boundary ◽  
The North ◽  
The North Atlantic

<p>The North Atlantic Deep Water (NADW) flows equatorward along the Deep Western Boundary Current (DWBC) as well as interior pathways and is a critical part of the Atlantic Meridional Overturning Circulation. Its upper layer, the Labrador Sea Water (LSW), is formed by open-ocean deep convection in the Labrador and Irminger Seas while its lower layers, the Iceland–Scotland Overflow Water (ISOW) and the Denmark Strait Overflow Water (DSOW), are formed north of the Greenland–Iceland–Scotland Ridge.</p><p>In recent years, more than two hundred acoustically-tracked subsurface floats have been deployed in the deep waters of the North Atlantic.  Studies to date have highlighted water mass pathways from launch locations, but due to limited float trajectory lengths, these studies have been unable to identify pathways connecting  remote regions.</p><p>This work presents a framework to explore deep water pathways from their respective sources in the North Atlantic using Markov Chain (MC) modeling and Transition Path Theory (TPT). Using observational trajectories released as part of OSNAP and the Argo projects, we constructed two MCs that approximate the lower and upper layers of the NADW Lagrangian dynamics. The reactive NADW pathways—directly connecting NADW sources with a target at 53°N—are obtained from these MCs using TPT.</p><p>Preliminary results show that twenty percent more pathways of the upper layer(LSW) reach the ocean interior compared to  the lower layer (ISOW, DSOW), which mostly flows along the DWBC in the subpolar North Atlantic. Also identified are the Labrador Sea recirculation pathways to the Irminger Sea and the direct connections from the Reykjanes Ridge to the eastern flank of the Mid–Atlantic Ridge, both previously observed. Furthermore, we quantified the eastern spread of the LSW to the area surrounding the Charlie–Gibbs Fracture Zone and compared it with previous analysis. Finally, the residence time of the upper and lower layers are assessed and compared to previous observations.</p>

scholarly journals Publisher Correction: Glacial–interglacial Nd isotope variability of North Atlantic Deep Water modulated by North American ice sheet

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ning Zhao ◽  
Delia W. Oppo ◽  
Kuo-Fang Huang ◽  
Jacob N. W. Howe ◽  
Jerzy Blusztajn ◽  
...  
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
North American ◽  
Ice Sheet ◽  
North Atlantic Deep Water ◽  
Nd Isotope

Late Pliocene variation in northern hemisphere ice sheets and North Atlantic deep water circulation

1989 ◽  
Vol 4 (4) ◽  
pp. 413-446 ◽  
Author(s):  
M. E. Raymo ◽  
W. F. Ruddiman ◽  
J. Backman ◽  
B. M. Clement ◽  
D. G. Martinson
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Deep Water ◽  
Ice Sheets ◽  
North Atlantic Deep Water ◽  
Water Circulation ◽  
Late Pliocene

scholarly journals The Role of Southern Ocean Surface Forcings and Mixing in the Global Conveyor

2008 ◽  
Vol 38 (7) ◽  
pp. 1377-1400 ◽  
Author(s):  
Daniele Iudicone ◽  
Gurvan Madec ◽  
Bruno Blanke ◽  
Sabrina Speich
Keyword(s):  
Southern Ocean ◽  
North Atlantic ◽  
Deep Water ◽  
Thermohaline Circulation ◽  
North Atlantic Deep Water ◽  
Surface Fluxes ◽  
Weddell Sea ◽  
Mode Water ◽  
Circumpolar Deep Water ◽  
Subantarctic Mode Water

Abstract Despite the renewed interest in the Southern Ocean, there are yet many unknowns because of the scarcity of measurements and the complexity of the thermohaline circulation. Hence the authors present here the analysis of the thermohaline circulation of the Southern Ocean of a steady-state simulation of a coupled ice–ocean model. The study aims to clarify the roles of surface fluxes and internal mixing, with focus on the mechanisms of the upper branch of the overturning. A quantitative dynamical analysis of the water-mass transformation has been performed using a new method. Surface fluxes, including the effect of the penetrative solar radiation, produce almost 40 Sv (1 Sv ≡ 106 m3 s−1) of Subantarctic Mode Water while about 5 Sv of the densest water masses (γ > 28.2) are formed by brine rejection on the shelves of Antarctica and in the Weddell Sea. Mixing transforms one-half of the Subantarctic Mode Water into intermediate water and Upper Circumpolar Deep Water while bottom water is produced by Lower Circumpolar Deep Water and North Atlantic Deep Water mixing with shelf water. The upwelling of part of the North Atlantic Deep Water inflow is due to internal processes, mainly downward propagation of the surface freshwater excess via vertical mixing at the base of the mixed layer. A complementary Lagrangian analysis of the thermohaline circulation will be presented in a companion paper.

scholarly journals Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend: COMMENT

Geology ◽  
2013 ◽  
Vol 41 (9) ◽  
pp. e291-e291 ◽  
Author(s):  
Martyn Stoker ◽  
Alick Leslie ◽  
Kevin Smith ◽  
Jana Ólavsdóttir ◽  
Howard Johnson ◽  
...  
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
North Atlantic Deep Water ◽  
Water Production ◽  
Global Cooling ◽  
Cooling Trend
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