Discovery of an unrecognized pathway carrying overflow waters toward the Faroe Bank Channel

The dense overflow waters of the Nordic Seas are an integral link and important diagnostic for the stability of the Atlantic Meridional Overturning Circulation (AMOC). The pathways feeding the overflow remain, however, poorly resolved. Here we use multiple observational platforms and an eddy-resolving ocean model to identify an unrecognized deep flow toward the Faroe Bank Channel. We demonstrate that anticyclonic wind forcing in the Nordic Seas via its regulation of the basin circulation plays a key role in activating an unrecognized overflow path from the Norwegian slope – at which times the overflow is anomalously strong. We further establish that, regardless of upstream pathways, the overflows are mostly carried by a deep jet banked against the eastern slope of the Faroe-Shetland Channel, contrary to previous thinking. This deep flow is thus the primary conduit of overflow water feeding the lower branch of the AMOC via the Faroe Bank Channel

The Iceland-Faroe slope jet: a conduit for dense water toward the Faroe Bank Channel overflow

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Semper, S., Pickart, R. S., Vage, K., Larsen, K. M. H., Hatun, H., & Hansen, B. The Iceland-Faroe slope jet: a conduit for dense water toward the Faroe Bank Channel overflow. Nature Communications, 11(1), (2020): 5390, doi:10.1038/s41467-020-19049-5.Dense water from the Nordic Seas passes through the Faroe Bank Channel and supplies the lower limb of the Atlantic Meridional Overturning Circulation, a critical component of the climate system. Yet, the upstream pathways of this water are not fully known. Here we present evidence of a previously unrecognised deep current following the slope from Iceland toward the Faroe Bank Channel using high-resolution, synoptic shipboard observations and long-term measurements north of the Faroe Islands. The bulk of the volume transport of the current, named the Iceland-Faroe Slope Jet (IFSJ), is relatively uniform in hydrographic properties, very similar to the North Icelandic Jet flowing westward along the slope north of Iceland toward Denmark Strait. This suggests a common source for the two major overflows across the Greenland-Scotland Ridge. The IFSJ can account for approximately half of the total overflow transport through the Faroe Bank Channel, thus constituting a significant component of the overturning circulation in the Nordic Seas.Support for this work was provided by the Bergen Research Foundation Grant BFS2016REK01 (S.S. and K.V.), the U.S. National Science Foundation Grants OCE-1558742 and OCE-1259618 (R.S.P.), the Danish Ministry of Climate, Energy and Utilities (K.M.H.L., H.H., and B.H.) and the European Union’s Horizon 2020 research and innovation programme under grant agreement 727852 (Blue-Action) (K.M.H.L., H.H., and B.H.)

Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic

The Atlantic Ocean overturning circulation is important to the climate system because it carries heat and carbon northward, and from the surface to the deep ocean. The high salinity of the subpolar North Atlantic is a prerequisite for overturning circulation, and strong freshening could herald a slowdown. We show that the eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of measurements. The cause was unusual winter wind patterns driving major changes in ocean circulation, including slowing of the North Atlantic Current and diversion of Arctic freshwater from the western boundary into the eastern basins. We find that wind-driven routing of Arctic-origin freshwater intimately links conditions on the North West Atlantic shelf and slope region with the eastern subpolar basins. This reveals the importance of atmospheric forcing of intra-basin circulation in determining the salinity of the subpolar North Atlantic

NACLIM - Fluxes: Iceland-Faroe Atlantic inflow transport

<p><strong>Last update: 31 October 2014</strong></p> <p><strong>Data set: </strong>Iceland-Faroe Atlantic inflow transport </p> <p><em>Preliminary results: HAV is in the process of recalculating the whole series (Update 31 October 2014)</em></p> <p><strong>Description: </strong>Weekly averaged volume flux of Atlantic water through section N (see map) crossing the Faroe Current</p> <p><strong>Period:</strong> June 1997 – May 2014 </p> <p><strong>Location:</strong> 62°20′ – 63°40′ N   6°05′ W</p> <p><strong>Instruments:</strong> Moored Acoustic Doppler Current Profilers (ADCP) and CTD sections </p> <p><strong>Variables: </strong>Atlantic water component of transport (Sv) through the section, which has come across the Iceland-Faroe Ridge </p> <p><strong>Source:</strong> Bogi Hansen and Karin Margretha H. Larsen (HAV)</p

The Arctic Mediterranean component of AMOC did NOT weaken during the last two decades

Presentation of new researc

The Iceland-Faroe Slope Jet: a conduit for dense water toward the Faroe Bank Channel overflow

Dense water from the Nordic Seas passes through the Faroe Bank Channel and supplies the lower limb of the Atlantic Meridional Overturning Circulation, a critical component of the climate system. Yet, the upstream pathways of this water are not fully known. Here we present evidence of a previously unrecognised deep current following the slope from Iceland toward the Faroe Bank Channel using high-resolution, synoptic shipboard observations and long-term measurements north of the Faroe Islands. The bulk of the volume transport of the current, named the Iceland-Faroe Slope Jet (IFSJ), is relatively uniform in hydrographic properties, very similar to the North Icelandic Jet flowing westward along the slope north of Iceland toward Denmark Strait. This suggests a common source for the two major overflows across the Greenland-Scotland Ridge. The IFSJ can account for approximately half of the total overflow transport through the Faroe Bank Channel, thus constituting a significant component of the overturning circulation in the Nordic Seas

Introduction to the Chemical Oceanography of Frontal Zones

This chapter provides a concise overview of the entire monograph by assembling summaries of 10 individual chapters starting with a global review of large-scale, persistent nutrient fronts of the World Ocean followed by regional chapters on the Arctic Ocean, North Atlantic, Baltic Sea, Kuroshio Current, and the Yellow Sea, a global review of CDOM dynamics at fronts, a chapter on persistent organic pollutants and marine organisms in the Kuroshio-Oyashio frontal zone, and two chapters on marine litter and its dynamics in frontal zones