Structure and Transport of the North Atlantic Current in the Eastern Subpolar Gyre From Sustained Glider Observations

L. Houpert, M. E. Inall, E. Dumont, S. Gary, C. Johnson, M. Porter, William E Johns, S. A. Cunningham

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Repeat glider sections obtained during 2014–2016, as part of the Overturning in the Subpolar North Atlantic Program, are used to quantify the circulation and transport of North Atlantic Current (NAC) branches over the Rockall Plateau. Using 16 glider sections collected along 58°N and between 21°W and 15°W, absolute geostrophic velocities are calculated, and subsequently the horizontal and vertical structure of the transport are characterized. The annual mean northward transport (± standard deviation) is 5.1 ± 3.2 Sv over the Rockall Plateau. During summer (May to October), the mean northward transport is stronger and reaches 6.7 ± 2.6 Sv. This accounts for 43% of the total NAC transport of upper-ocean waters (σO<27.55 kg/m3) estimated by Sarafanov et al. (2012, https://doi.org/10.1029/2011JC007572) along 59.5°N, between the Reykjanes Ridge and Scotland. Two quasi-permanent northward flowing branches of the NAC are identified: (i) the Hatton Bank Jet (6.3 ± 2.1 Sv) over the eastern flank of the Iceland Basin (20.5°W to 18.5°W) and (ii) the Rockall Bank Jet (1.5 ± 0.7 Sv) over the eastern flank of the Hatton-Rockall Basin (16°W to 15°W). Transport associated with the Rockall Bank Jet is mostly depth independent during summer, while 30% of the Hatton Bank Jet transport is due to vertical geostrophic shear. Uncertainties are estimated for each individual glider section using a Monte Carlo approach, and mean uncertainties of the absolute transport are less than 0.5 Sv. Although comparisons with altimetry-based estimates indicate similar large-scale circulation patterns, altimetry data do not resolve small mesoscale current bands in the Hatton-Rockall Basin which are strongly needed for the right transport estimates.

Original languageEnglish (US)
Pages (from-to)6019-6038
Number of pages20
JournalJournal of Geophysical Research: Oceans
Volume123
Issue number8
DOIs
StatePublished - Aug 1 2018
Externally publishedYes

Fingerprint

gliders
Gliders
gyre
basins
altimetry
plateaus
uncertainty
summer
Iceland
basin
plateau
Scotland
shears
upper ocean
estimates
seawater
ridges
standard deviation
oceans
shear

Keywords

  • AMOC
  • boundary current
  • glider
  • North Atlantic Current
  • observing system
  • ocean transport

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Structure and Transport of the North Atlantic Current in the Eastern Subpolar Gyre From Sustained Glider Observations. / Houpert, L.; Inall, M. E.; Dumont, E.; Gary, S.; Johnson, C.; Porter, M.; Johns, William E; Cunningham, S. A.

In: Journal of Geophysical Research: Oceans, Vol. 123, No. 8, 01.08.2018, p. 6019-6038.

Research output: Contribution to journalArticle

Houpert, L. ; Inall, M. E. ; Dumont, E. ; Gary, S. ; Johnson, C. ; Porter, M. ; Johns, William E ; Cunningham, S. A. / Structure and Transport of the North Atlantic Current in the Eastern Subpolar Gyre From Sustained Glider Observations. In: Journal of Geophysical Research: Oceans. 2018 ; Vol. 123, No. 8. pp. 6019-6038.
@article{ed79812b0fe047e3b7e32825dc1f69a6,
title = "Structure and Transport of the North Atlantic Current in the Eastern Subpolar Gyre From Sustained Glider Observations",
abstract = "Repeat glider sections obtained during 2014–2016, as part of the Overturning in the Subpolar North Atlantic Program, are used to quantify the circulation and transport of North Atlantic Current (NAC) branches over the Rockall Plateau. Using 16 glider sections collected along 58°N and between 21°W and 15°W, absolute geostrophic velocities are calculated, and subsequently the horizontal and vertical structure of the transport are characterized. The annual mean northward transport (± standard deviation) is 5.1 ± 3.2 Sv over the Rockall Plateau. During summer (May to October), the mean northward transport is stronger and reaches 6.7 ± 2.6 Sv. This accounts for 43{\%} of the total NAC transport of upper-ocean waters (σO<27.55 kg/m3) estimated by Sarafanov et al. (2012, https://doi.org/10.1029/2011JC007572) along 59.5°N, between the Reykjanes Ridge and Scotland. Two quasi-permanent northward flowing branches of the NAC are identified: (i) the Hatton Bank Jet (6.3 ± 2.1 Sv) over the eastern flank of the Iceland Basin (20.5°W to 18.5°W) and (ii) the Rockall Bank Jet (1.5 ± 0.7 Sv) over the eastern flank of the Hatton-Rockall Basin (16°W to 15°W). Transport associated with the Rockall Bank Jet is mostly depth independent during summer, while 30{\%} of the Hatton Bank Jet transport is due to vertical geostrophic shear. Uncertainties are estimated for each individual glider section using a Monte Carlo approach, and mean uncertainties of the absolute transport are less than 0.5 Sv. Although comparisons with altimetry-based estimates indicate similar large-scale circulation patterns, altimetry data do not resolve small mesoscale current bands in the Hatton-Rockall Basin which are strongly needed for the right transport estimates.",
keywords = "AMOC, boundary current, glider, North Atlantic Current, observing system, ocean transport",
author = "L. Houpert and Inall, {M. E.} and E. Dumont and S. Gary and C. Johnson and M. Porter and Johns, {William E} and Cunningham, {S. A.}",
year = "2018",
month = "8",
day = "1",
doi = "10.1029/2018JC014162",
language = "English (US)",
volume = "123",
pages = "6019--6038",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
publisher = "Wiley-Blackwell",
number = "8",

}

TY - JOUR

T1 - Structure and Transport of the North Atlantic Current in the Eastern Subpolar Gyre From Sustained Glider Observations

AU - Houpert, L.

AU - Inall, M. E.

AU - Dumont, E.

AU - Gary, S.

AU - Johnson, C.

AU - Porter, M.

AU - Johns, William E

AU - Cunningham, S. A.

PY - 2018/8/1

Y1 - 2018/8/1

N2 - Repeat glider sections obtained during 2014–2016, as part of the Overturning in the Subpolar North Atlantic Program, are used to quantify the circulation and transport of North Atlantic Current (NAC) branches over the Rockall Plateau. Using 16 glider sections collected along 58°N and between 21°W and 15°W, absolute geostrophic velocities are calculated, and subsequently the horizontal and vertical structure of the transport are characterized. The annual mean northward transport (± standard deviation) is 5.1 ± 3.2 Sv over the Rockall Plateau. During summer (May to October), the mean northward transport is stronger and reaches 6.7 ± 2.6 Sv. This accounts for 43% of the total NAC transport of upper-ocean waters (σO<27.55 kg/m3) estimated by Sarafanov et al. (2012, https://doi.org/10.1029/2011JC007572) along 59.5°N, between the Reykjanes Ridge and Scotland. Two quasi-permanent northward flowing branches of the NAC are identified: (i) the Hatton Bank Jet (6.3 ± 2.1 Sv) over the eastern flank of the Iceland Basin (20.5°W to 18.5°W) and (ii) the Rockall Bank Jet (1.5 ± 0.7 Sv) over the eastern flank of the Hatton-Rockall Basin (16°W to 15°W). Transport associated with the Rockall Bank Jet is mostly depth independent during summer, while 30% of the Hatton Bank Jet transport is due to vertical geostrophic shear. Uncertainties are estimated for each individual glider section using a Monte Carlo approach, and mean uncertainties of the absolute transport are less than 0.5 Sv. Although comparisons with altimetry-based estimates indicate similar large-scale circulation patterns, altimetry data do not resolve small mesoscale current bands in the Hatton-Rockall Basin which are strongly needed for the right transport estimates.

AB - Repeat glider sections obtained during 2014–2016, as part of the Overturning in the Subpolar North Atlantic Program, are used to quantify the circulation and transport of North Atlantic Current (NAC) branches over the Rockall Plateau. Using 16 glider sections collected along 58°N and between 21°W and 15°W, absolute geostrophic velocities are calculated, and subsequently the horizontal and vertical structure of the transport are characterized. The annual mean northward transport (± standard deviation) is 5.1 ± 3.2 Sv over the Rockall Plateau. During summer (May to October), the mean northward transport is stronger and reaches 6.7 ± 2.6 Sv. This accounts for 43% of the total NAC transport of upper-ocean waters (σO<27.55 kg/m3) estimated by Sarafanov et al. (2012, https://doi.org/10.1029/2011JC007572) along 59.5°N, between the Reykjanes Ridge and Scotland. Two quasi-permanent northward flowing branches of the NAC are identified: (i) the Hatton Bank Jet (6.3 ± 2.1 Sv) over the eastern flank of the Iceland Basin (20.5°W to 18.5°W) and (ii) the Rockall Bank Jet (1.5 ± 0.7 Sv) over the eastern flank of the Hatton-Rockall Basin (16°W to 15°W). Transport associated with the Rockall Bank Jet is mostly depth independent during summer, while 30% of the Hatton Bank Jet transport is due to vertical geostrophic shear. Uncertainties are estimated for each individual glider section using a Monte Carlo approach, and mean uncertainties of the absolute transport are less than 0.5 Sv. Although comparisons with altimetry-based estimates indicate similar large-scale circulation patterns, altimetry data do not resolve small mesoscale current bands in the Hatton-Rockall Basin which are strongly needed for the right transport estimates.

KW - AMOC

KW - boundary current

KW - glider

KW - North Atlantic Current

KW - observing system

KW - ocean transport

UR - http://www.scopus.com/inward/record.url?scp=85052535258&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85052535258&partnerID=8YFLogxK

U2 - 10.1029/2018JC014162

DO - 10.1029/2018JC014162

M3 - Article

AN - SCOPUS:85052535258

VL - 123

SP - 6019

EP - 6038

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 8

ER -