• Alfultis, M. A., , and P. Cornillon, 2001: Annual and interannual changes in the North Atlantic STMW layer properties. J. Phys. Oceanogr., 31, 20662086, doi:10.1175/1520-0485(2001)031<2066:AAICIT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Biastoch, A., , C. W. Böning, , J. Getzlaff, , J.-M. Molines, , and G. Madec, 2008: Causes of interannual–decadal variability in the meridional overturning circulation of the midlatitude North Atlantic Ocean. J. Climate, 21, 65996615, doi:10.1175/2008JCLI2404.1.

    • Search Google Scholar
    • Export Citation
  • Böning, C. W., , and M. D. Cox, 1988: Particle dispersion and mixing of conservative properties in an eddy-resolving model. J. Phys. Oceanogr., 18, 320338, doi:10.1175/1520-0485(1988)018<0320:PDAMOC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Böning, C. W., , M. Scheinert, , J. Dengg, , A. Biastoch, , and A. Funk, 2006: Decadal variability of subpolar gyre transport and its reverberation in the North Atlantic overturning. Geophys. Res. Lett., 33, L21S01, doi:10.1029/2006GL026906.

    • Search Google Scholar
    • Export Citation
  • Boyer, T. P., , and S. Levitus, 1997: Objective analyses of temperature and salinity for the world ocean on a ¼ degree grid. NOAA Atlas NESDIS 11, U.S. Government Printing Office Tech. Rep., 83 pp.

  • Burkholder, K. C., , and M. S. Lozier, 2011: Subtropical to subpolar pathways in the North Atlantic: Deductions from Lagrangian trajectories. J. Geophys. Res., 116, C07017, doi:10.1029/2010JC006697.

    • Search Google Scholar
    • Export Citation
  • Davis, X. J., , F. Straneo, , Y.-O. Kwon, , K. A. Kelly, , and J. M. Toole, 2013: Evolution and formation of North Atlantic Eighteen Degree Water in the Sargasso Sea from moored data. Deep-Sea Res. II, 91, 1124, doi:10.1016/j.dsr2.2013.02.024.

    • Search Google Scholar
    • Export Citation
  • Dong, S., , S. L. Hautala, , and K. A. Kelly, 2007: Interannual variations in upper-ocean heat content and heat transport convergence in the western North Atlantic. J. Phys. Oceanogr., 37, 26822697, doi:10.1175/2007JPO3645.1.

    • Search Google Scholar
    • Export Citation
  • Forget, G., , G. Maze, , M. Buckley, , and J. Marshall, 2011: Estimated seasonal cycle of North Atlantic Eighteen Degree Water volume. J. Phys. Oceanogr., 41, 269286, doi:10.1175/2010JPO4257.1.

    • Search Google Scholar
    • Export Citation
  • Fratantoni, D. M., , Y.-O. Kwon, , and B. A. Hodges, 2013: Direct observation of subtropical mode water circulation in the western North Atlantic Ocean. Deep-Sea Res. II, 91, 3556, doi:10.1016/j.dsr2.2013.02.027.

    • Search Google Scholar
    • Export Citation
  • Fuglister, F. C., , and A. D. Voorhis, 1965: A new method for tracking the Gulf Stream. Limnol. Oceanogr., 10, 115124.

  • Gary, S. F., , M. S. Lozier, , C. W. Böning, , and A. Biastoch, 2011: Deciphering the pathways for the deep limb of the meridional overturning circulation. Deep-Sea Res. II, 58, 17811797, doi:10.1016/j.dsr2.2010.10.059.

    • Search Google Scholar
    • Export Citation
  • Grist, J. P., , and S. A. Josey, 2003: Inverse analysis adjustment of the SOC air–sea flux climatology using ocean heat transport constraints. J. Climate, 16, 32743295, doi:10.1175/1520-0442(2003)016<3274:IAAOTS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Hanawa, K., , and L. Talley, 2001: Mode waters. Ocean Circulation and Climate, J. Siedler, J. Church, and J. Gould, Eds., International Geophysics Series, Vol. 77, Academic Press, 373–386.

  • Hüttl‐Kabus, S., , and C. W. Böning, 2008: Pathways and variability of the off‐equatorial undercurrents in the Atlantic Ocean. J. Geophys. Res., 113, C10018, doi:10.1029/2007JC004700.

    • Search Google Scholar
    • Export Citation
  • Jenkins, W. J., 1988: The use of anthropogenic tritium and helium-3 to study subtropical gyre ventilation and circulation. Philos. Trans. Roy. Soc. London, A325, 4361, doi:10.1098/rsta.1988.0041.

    • Search Google Scholar
    • Export Citation
  • Joyce, T. M., 2012: New perspectives on Eighteen-Degree Water formation in the North Atlantic. J. Oceanogr., 68, 4552, doi:10.1007/s10872-011-0029-0.

    • Search Google Scholar
    • Export Citation
  • Joyce, T. M., , L. N. Thomas, , and F. Bahr, 2009: Wintertime observations of subtropical mode water formation within the Gulf Stream. Geophys. Res. Lett., 36, L02607, doi:10.1029/2008GL035918.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E. M., and et al. , 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437471, doi:10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Kelly, K. A., , R. J. Small, , R. M. Samelson, , B. Qiu, , T. M. Joyce, , Y.-O. Kwon, , and M. Cronin, 2010: Western boundary currents and frontal air–sea interaction: Gulf Stream and Kuroshio Extension. J. Climate, 23, 56445667, doi:10.1175/2010JCLI3346.1.

    • Search Google Scholar
    • Export Citation
  • Klein, B., , and N. Hogg, 1996: On the variability of 18 Degree Water formation as observed from moored instruments at 55°W. Deep-Sea Res. I, 43, 17771806, doi:10.1016/S0967-0637(96)00069-6.

    • Search Google Scholar
    • Export Citation
  • Kwon, Y.-O., , and S. C. Riser, 2004: North Atlantic Subtropical Mode Water: A history of ocean–atmosphere interaction 1961–2000. Geophys. Res. Lett., 31, L19307, doi:10.1029/2004GL021116.

    • Search Google Scholar
    • Export Citation
  • Large, W. G., , and S. G. Yeager, 2009: The global climatology of an interannually varying air–sea flux data set. Climate Dyn., 33, 341364, doi:10.1007/s00382-008-0441-3.

    • Search Google Scholar
    • Export Citation
  • LeBel, D. A., and et al. , 2008: The formation rate of North Atlantic Deep Water and Eighteen Degree Water calculated from CFC-11 inventories observed during WOCE. Deep-Sea Res. I, 55, 891910, doi:10.1016/j.dsr.2008.03.009.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., , and T. P. Boyer, 1994: Temperature. Vol. 4, World Ocean Atlas 1994, NOAA Atlas NESDIS 4, 117 pp.

  • Levitus, S., , R. Burgett, , and T. P. Boyer, 1994: Salinity. Vol. 3, World Ocean Atlas 1994, NOAA Atlas NESDIS 3, 99 pp.

  • Lozier, M. S., , W. B. Owens, , and R. G. Curry, 1995: The climatology of the North Atlantic. Prog. Oceanogr., 36, 144, doi:10.1016/0079-6611(95)00013-5.

    • Search Google Scholar
    • Export Citation
  • Lumpkin, R., , A.-M. Treguier, , and K. Speer, 2002: Lagrangian eddy scales in the northern Atlantic Ocean. J. Phys. Oceanogr., 32, 24252440, doi:10.1175/1520-0485-32.9.2425.

    • Search Google Scholar
    • Export Citation
  • Maze, G., , and J. Marshall, 2011: Diagnosing the observed seasonal cycle of the Atlantic Subtropical Mode Water using potential vorticity and its attendant theorems. J. Phys. Oceanogr., 41, 19861999, doi:10.1175/2011JPO4576.1.

    • Search Google Scholar
    • Export Citation
  • Maze, G., , G. Forget, , M. Buckley, , and J. Marshall, 2009: Using transformation and formation maps to study the role of air–sea heat fluxes in North Atlantic Eighteen Degree Water formation. J. Phys. Oceanogr., 39, 18181835, doi:10.1175/2009JPO3985.1.

    • Search Google Scholar
    • Export Citation
  • McDowell, S., , P. B. Rhines, , and T. Keffer, 1982: North Atlantic potential vorticity and its relation to the general circulation. J. Phys. Oceanogr., 12, 14171436, doi:10.1175/1520-0485(1982)012<1417:NAPVAI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • National Oceanographic Data Center, cited2012: World Ocean database. [Available online at http://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch.html.]

  • Pacanowski, R. C., 1996: MOM2 version 2.0 (beta) documentation, user’s guide, and reference manual. GFDL Ocean Tech. Rep. 3.2, 350 pp. [Available online at http://gfdl.noaa.gov/cms-filesystem-action/model_development/ocean/manual2.2.pdf.]

  • Palter, J. B., , M. S. Lozier, , and R. T. Barber, 2005: The effect of advection on the nutrient reservoir in the North Atlantic subtropical gyre. Nature, 437, 687692, doi:10.1038/nature03969.

    • Search Google Scholar
    • Export Citation
  • Rhines, P. B., , and W. R. Holland, 1979: A theoretical discussion of eddy-driven mean flows. Dyn. Atmos. Oceans, 3, 289325, doi:10.1016/0377-0265(79)90015-0.

    • Search Google Scholar
    • Export Citation
  • Rhines, P. B., , and W. R. Young, 1982: Homogenization of potential vorticity in planetary gyres. J. Fluid Mech., 122, 347367, doi:10.1017/S0022112082002250.

    • Search Google Scholar
    • Export Citation
  • Siedler, G., , A. Kuhl, , and W. Zenk, 1987: The Madeira Mode Water. J. Phys. Oceanogr., 17, 15611570, doi:10.1175/1520-0485(1987)017<1561:TMMW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Silverthorne, K. E., , and J. M. Toole, 2013: Quasi-Lagrangian observations of the upper ocean response to wintertime forcing in the Gulf Stream. Deep-Sea Res. I, 91, 2534, doi:10.1016/j.dsr2.2013.02.021.

    • Search Google Scholar
    • Export Citation
  • Speer, K., , and E. Tziperman, 1992: Rates of water mass formation in the North Atlantic Ocean. J. Phys. Oceanogr., 22, 93104, doi:10.1175/1520-0485(1992)022<0093:ROWMFI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Talley, L. D., , and M. E. Raymer, 1982: Eighteen Degree Water variability. J. Mar. Res., 40, 757775.

  • Worthington, L., 1958: The 18°C water in the Sargasso Sea. Deep-Sea Res., 5, 297305, doi:10.1016/0146-6313(58)90026-1.

  • Worthington, L., 1976: On the North Atlantic Circulation. Johns Hopkins University Press, 110 pp.

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The Fate of North Atlantic Subtropical Mode Water in the FLAME Model

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  • 1 Duke University, Durham, North Carolina
  • | 2 Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
  • | 3 Kyungpook National University, Sangju, South Korea
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Abstract

North Atlantic Subtropical Mode Water, also known as Eighteen Degree Water (EDW), has the potential to store heat anomalies through its seasonal cycle: the water mass is in contact with the atmosphere in winter, isolated from the surface for the rest of the year, and reexposed the following winter. Though there has been recent progress in understanding EDW formation processes, an understanding of the fate of EDW following formation remains nascent. Here, particles are launched within the EDW of an eddy-resolving model, and their fate is tracked as they move away from the formation region. Particles in EDW have an average residence time of ~10 months, they follow the large-scale circulation around the subtropical gyre, and stratification is the dominant criteria governing the exit of particles from EDW. After sinking into the layers beneath EDW, particles are eventually exported to the subpolar gyre. The spreading of particles is consistent with the large-scale potential vorticity field, and there are signs of a possible eddy-driven mean flow in the southern portion of the EDW domain. The authors also show that property anomalies along particle trajectories have an average integral time scale of ~3 months for particles that are in EDW and ~2 months for particles out of EDW. Finally, it is shown that the EDW turnover time for the model in an Eulerian frame (~3 yr) is consistent with the turnover time computed from the Lagrangian particles provided that the effects of exchange between EDW and the surrounding waters are included.

Corresponding author address: Stefan Gary, Division of Earth and Ocean Sciences, Duke University, Box 90227, Durham, NC 27708. E-mail: stefan.gary@duke.edu; stefan.gary@sams.ac.uk

Abstract

North Atlantic Subtropical Mode Water, also known as Eighteen Degree Water (EDW), has the potential to store heat anomalies through its seasonal cycle: the water mass is in contact with the atmosphere in winter, isolated from the surface for the rest of the year, and reexposed the following winter. Though there has been recent progress in understanding EDW formation processes, an understanding of the fate of EDW following formation remains nascent. Here, particles are launched within the EDW of an eddy-resolving model, and their fate is tracked as they move away from the formation region. Particles in EDW have an average residence time of ~10 months, they follow the large-scale circulation around the subtropical gyre, and stratification is the dominant criteria governing the exit of particles from EDW. After sinking into the layers beneath EDW, particles are eventually exported to the subpolar gyre. The spreading of particles is consistent with the large-scale potential vorticity field, and there are signs of a possible eddy-driven mean flow in the southern portion of the EDW domain. The authors also show that property anomalies along particle trajectories have an average integral time scale of ~3 months for particles that are in EDW and ~2 months for particles out of EDW. Finally, it is shown that the EDW turnover time for the model in an Eulerian frame (~3 yr) is consistent with the turnover time computed from the Lagrangian particles provided that the effects of exchange between EDW and the surrounding waters are included.

Corresponding author address: Stefan Gary, Division of Earth and Ocean Sciences, Duke University, Box 90227, Durham, NC 27708. E-mail: stefan.gary@duke.edu; stefan.gary@sams.ac.uk
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