Abstract
Most open ocean and climate models assume a constant background mixing; however, vertical mixing should be reduced under the sea ice in polar region because the sea-ice cover acts as an insulator against the momentum transfer between the atmosphere and ocean. Using a global Ocean General Circulation Model (OGCM), we show that the Atlantic meridional overturning circulation (AMOC) can be substantially affected by reduced vertical mixing under the sea ice. When the background diffusivity under the sea ice is reduced by 1 order less than that in ice-free regions, the volume transport of the AMOC in the upper 3000 m is increased by up to 14% accordingly. The numerical experiment suggests that the reduced background diffusivity makes waters denser in the Arctic Ocean and the denser water is transported into the Nordic Seas to push up the isopycnal surfaces over the Greenland- Iceland-Scotland Ridge. Consequently, the AMOC is enhanced by overflows of the denser water crossing the Denmark Strait.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Antonov JI, Seidov D, Boyer TP, Locarnini RA, Mishonov AV, Garcia HE, Baranova OK, Zweng MM, Johnson DR (2010) World Ocean Atlas 2009, Volume 2: Salinity. U.S. Government Printing Office, Washington, DC, NOAA Atlas NESDIS 69, 184 p
Conkright ME, Locarnini RA, Garcia HE, O’ Brien TD, Boyer TP, Stephens C, Antonov JI (2002) World Ocean Atlas 2001: Objective Analyses, Data Statistics, and Figures, CD-ROM Documentation. Ocean Climate Laboratory, National Oceanographic Data Center Internal Report 17, 21 p
Cunningham SA, Kanzow T, Rayner D, Baringer MO, Johns WE, Marotzke J, Longworth HR, Grant EM, Hirschi JJM, Beal LM, Meinen CS, Bryden HL (2007) Temporal variability of the Atlantic meridional overturning circulation at 26.5°N. Science 317:935–938. doi:10.1126/science.1141304
Döscher R, Beckmann A (2000) Effects of a bottom boundary layer parameterization in a coarse-resolution model of the North Atlantic Ocean. J Atmos Ocean Tech 17:698–707
Döscher R, Redler R (1997) The relative importance of northern overflow and subpolar deep convection for the North Atlantic thermohalince circulation. J Phys Oceanogr 27:1894–1902
Gent PR, McWilliams JC (1990) Isopycnal mixing in ocean circulation models. J Phys Oceanogr 20:150–155
Griffies SM, Gnanadesikan A, Dixon KW, Dunne JP, Gerdes R, Harrison MJ, Rosati A, Russell JL, Samuels BL, Spelman MJ, Winton M, Zhang R (2005) Formulation of an ocean model for global climate simulations. Ocean Sci 1:45–79
Guthrie JD, Morison JH, Fer I (2013) Revisiting internal waves and mixing in the Arcic Ocean. J Geophys Res-Oceans 118:3966–3977. doi:10.1002/jgrc.20294
Karcher M, Beszczynska ? Möller A, Kauker F, Gerdes R, Heyen S, Rudels B, Schauer U (2011) Arctic Ocean warming and its consequences for the Denmark Strait overflow. J Geophys Res 116:C02037. doi:10.1029/2010JC006265
Kösters F, Käse RH, Schmittner A, Hermann P (2005) The effect of Denmark Strait overflow on the Atlantic Meridional Overturning Circulation. Geophys Res Lett 32:L04602. doi:10.1029/2004GL022112
Large WG, McWilliams JC, Doney SC (1994) Oceanic vertical mixing: a review and a model with a nonlocal boundary layer parameterization. Rev Geophys 32:363–403
Large WG, Yeager SG (2004) Diurnal to decadal global forcing for ocean and sea-ice models: the data sets and flux climatologies. National Center for Atmospheric Research, Technical Report TN-460+STR, 105 p http://opensky.library.ucar.edu/collections/TECH-NOTE-000-000-000-601
Levine MD, Paulson CA, Morison JH (1985) Internal waves in the Arctic Ocean: comparison with low-latitude observations. J Phys Oceanogr 15:805–809
Levine MD, Paulson CA, Morison JH (1987) Observations of internal gravity waves under the Arctic pack ice. J Geophys Res 92(C1):779–782
Locarnini RA, Mishonov AV, Antonov JI, Boyer TP, Garcia HE, Baranova OK, Zweng MM, Johnson DR (2010) World Ocean Atlas 2009, Volume 1: Temperature. U.S. Government Printing Office, Washington, DC, NOAA Atlas NESDIS 68, 184 p
Lozier MS, Roussenov V, Reed MSC, Williams RG (2010) Opposing decadal changes for the North Atlantic meridional overturning circulation. Nature Geosci 3:728–734. doi:10.1038/ngeo947
Morison JH, Long CE, Levine MD (1985) Internal wave dissipation under sea ice. J Geophys Res 90(11):959–966
Nguyen AT, Menemenlis D, Kwok R (2011) Arctic ice-ocean simulation with optimized model parameters: approach and assessment. J Geophys Res 116:C04025. doi:10.1029/2010JC006573
Perovich DK, Richter-Menge JA (2009) Loss of sea ice in the Arctic. Annu Rev Mar Sci 1:417–441. doi:10.1146/annurev.marine.010908.163805
Roberts MJ, Wood RA (1997) Topographic sensitivity studies with a Bryan-Cox type Ocean model. J Phys Oceanogr 27:823–836
Simmons HL, Jayne SR, St.Laurent LC, Weaver AJ (2004) Tidally driven mixing in a numerical model of the ocean general circulation. Ocean Model 6:245–263
Spall MA (2013) On the circulation of Atlantic Water in the Arctic Ocean. J Phys Oceanogr 43:2352–2371
Stouffer RJ, Yin J, Gregory JM, Dixon KW, Spelman MJ, Hurlin W, Weaver AJ, Eby M, Flato GM, Hasumi H, Hu A, Jungclaus JH, Kamenkovich IV, Levermann A, Montoya M, Murakami S, Nawrath S, Oka A, Peltier WR, Robitaille DY, Sokolov A, Vettoretti G, Weber SL (2006) Investigating the causes of the response of the thermohaline circulation to past and future climate changes. J Climate 19:1365–1387
Swingedouw D, Rodehacke CB, Behrens E, Menary M, Olsen SM, Gao Y, Mikolajewicz U, Mignot J, Biastoch A (2013) Decadal fingerprints of freshwater discharge around Greenland in a multi-model ensemble. Clim Dynam 41:695–720. doi:10.1007/s00382-012-1479-9
Steele M, Morley R, Ermold W (2001) PHC: a global ocean hydrography with a high-quality Arctic Ocean. J Climate 14:2079–2087
Whitehead JA, Leetmaa A, Knox RA (1974) Rotating hydraulics of strait and sill flows. Gephys Fluid Dyn 6:101–125
Winton M (2000) A reformulated three-layer sea ice model. J Atmos Ocean Tech 17:525–531
Zhang J, Steele M (2007) Effect of vertical mixing on the Atlantic Water layer circulation in the Arctic Ocean. J Geophys Res 112:C04S04. doi:10.1029/2006JC003732
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kim, S.Y., Lee, H.J., Park, JH. et al. Effects of reduced vertical mixing under sea ice on Atlantic meridional overturning circulation (AMOC) in a global ice-ocean model. Ocean Sci. J. 50, 155–161 (2015). https://doi.org/10.1007/s12601-015-0012-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12601-015-0012-6