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Climate Dynamics

, Volume 53, Issue 1–2, pp 1–19 | Cite as

The ‘sticky’ ITCZ: ocean-moderated ITCZ shifts

  • Brian GreenEmail author
  • John Marshall
  • Jean-Michel Campin
Article

Abstract

Across a range of simulations with a coupled atmosphere–ocean climate model, shifts in the intertropical convergence zone (ITCZ) are induced by an interhemispheric heating contrast. The response to heating anomalies which are polar amplified are contrasted with those which are largest in the tropics. First, we find that ITCZ shifts are always damped relative to simulations in which the ocean circulation is held fixed, irrespective of the heating distribution, keeping the ITCZ “stuck” to latitudes near the equator. The damping is primarily due to the ocean’s anomalous cross-equatorial energy transport associated with the coupling of the trade winds to an oceanic cross-equatorial cell (CEC). Second, we find that the damping effect is strongest when the forcing distribution is polar-amplified, which enhances the gross stability of the CEC and maximizes the efficiency of its cross-equatorial energy transport. Third, we argue that the ocean’s energy transport can have secondary impacts on ITCZ shifts through its interaction with climate feedbacks. Finally, we discuss the implications of our study for our understanding of the role of CECs in damping ITCZ shifts and the atmosphere’s energy balance.

Keywords

Intertropical convergence zone Trade winds Hadley cell Subtropical cell 

Notes

Acknowledgements

This research was supported by a Grant from the National Oceanic and Atmospheric Administration. We appreciate useful comments on earlier drafts from Tim Cronin, Paul O’Gorman, Gerard Roe, Sarah Kang, and one anonymous reviewer. An earlier version of this article was published as a part of Brian Green’s PhD thesis, “Coupling of the Intertropical Convergence Zone and the Hadley Cells to the Ocean's Circulation,” © 2018 Massachusetts Institute of Technology.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. Adcroft A, Campin JM, Hill C, Marshall J (2004) Implementation of an atmosphere-ocean general circulation model on the expanded spherical cube. Mon Weather Rev 132:2845–2863.  https://doi.org/10.1175/MWR2823.1 CrossRefGoogle Scholar
  2. Bischoff T, Schneider T (2016) The equatorial energy balance, ITCZ position, and double-ITCZ bifurcations. J Clim 29:2997–3013.  https://doi.org/10.1175/JCLI-D-15-0328.1 CrossRefGoogle Scholar
  3. Byrne MP, O’Gorman PA (2013) Land–ocean warming contrast over a wide range of climates: convective quasi-equilibrium theory and idealized simulations. J Clim 26:4000–4016.  https://doi.org/10.1175/JCLI-D-12-00262.1 CrossRefGoogle Scholar
  4. Czaja A, Marshall J (2006) The partitioning of poleward heat transport between the atmosphere and ocean. J Atmos Sci 63:1498–1511.  https://doi.org/10.1175/JAS3695.1 CrossRefGoogle Scholar
  5. Donohoe A, Marshall J, Ferreira D, McGee D (2013) The relationship between ITCZ location and cross-equatorial atmospheric heat transport: from the seasonal cycle to the last glacial maximum. J Clim 26:3597–3618.  https://doi.org/10.1175/JCLI-D-12-00467.1 CrossRefGoogle Scholar
  6. Ferrari R, Ferreira D (2011) What processes drive the ocean heat transport? Oceanmodel 38:171–186.  https://doi.org/10.1016/j.ocemod.2011.02.013 Google Scholar
  7. Ferreira D, Marshall J, Campin JM (2010) Localization of deep water formation: role of atmospheric moisture transport and geometrical constraints on ocean circulation. J Clim 23:1456–1476.  https://doi.org/10.1175/2009JCLI3197.1 CrossRefGoogle Scholar
  8. Feulner G, Rahmstorf S, Levermann A, Volkwardt S (2013) On the origin of the surface air temperature difference between the hemispheres in Earth’s present-day climate. J Clim 26:7136–7150.  https://doi.org/10.1175/JCLI-D-12-00636.1 CrossRefGoogle Scholar
  9. Frierson DMW (2007) The dynamics of idealized convection schemes and their effect on the zonally averaged tropical circulation. J Atmos Sci 64:1959–1976.  https://doi.org/10.1175/JAS3935.1 CrossRefGoogle Scholar
  10. Green B, Marshall J (2017) Coupling of trade winds with ocean circulation damps ITCZ shifts. J Clim 30:4395–4411.  https://doi.org/10.1175/JCLI-D-16-0818.1 CrossRefGoogle Scholar
  11. Griffies SM et al (2005) Formulation of an ocean model for global climate simulations. Ocean Sci 1:45–79.  https://doi.org/10.5194/os-1-45-2005 CrossRefGoogle Scholar
  12. Hawcroft M, Haywood JM, Collins M, Jones A, Jones AC, Stephens G (2016) Southern Ocean albedo, inter-hemispheric energy transports and the double ITCZ: global impacts of biases in a coupled model. Clim Dyn 1–17.  https://doi.org/10.1007/s00382-016-3205-5
  13. Held IM (2001) The partitioning of the poleward energy transport between the tropical ocean and atmosphere. J Atmos Sci 58:943–948.  https://doi.org/10.1175/1520-0469(2001)058%3C0943:TPOTPE%3E2.0.CO;2 CrossRefGoogle Scholar
  14. Hüttl-Kabus S, Böning CW (2008) Pathways and variability of the off-equatorial undercurrents in the Atlantic Ocean. J Geophys Res 113:C10018.  https://doi.org/10.1029/2007JC004700 CrossRefGoogle Scholar
  15. Jackett DR, McDougall TJ (1995) Minimal adjustment of hydrographic profiles to achieve static stability. J Atmos Ocean Technol 12:381–389.  https://doi.org/10.1175/1520-0426(1995)012%3C0381:MAOHPT%3E2.0.CO;2 CrossRefGoogle Scholar
  16. Kang SM, Held IM, Frierson DMW, Zhao M (2008) The response of the ITCZ to extratropical thermal forcing: idealized slab-ocean experiments with a GCM. J Clim 21:3521–3532.  https://doi.org/10.1175/2007JCLI2146.1 CrossRefGoogle Scholar
  17. Kang SM, Frierson DMW, Held IM (2009) The tropical response to extratropical thermal forcing in an idealized GCM: the importance of radiative feedbacks and convective parametrization. J Atmos Sci 66:2812–2827.  https://doi.org/10.1175/2009JAS2924.1 CrossRefGoogle Scholar
  18. Kang SM, Held IM, Xie S-P (2014) Contrasting the tropical responses to zonally asymmetric extratropical and tropical thermal forcing. Clim Dyn 42:2033–2043.  https://doi.org/10.1007/s00382-013-1863-0 CrossRefGoogle Scholar
  19. Kang SM, Seager R, Frierson DMW, Liu X (2015) Croll revisited: why is the northern hemisphere warmer than the southern hemisphere? Clim Dyn 44:1457–1472.  https://doi.org/10.1007/s00382-014-2147-z CrossRefGoogle Scholar
  20. Kang SM, Shin Y, Xie S-P (2018a) Extratropical forcing and tropical rainfall distribution: energetics framework and ocean Ekman advection. npj Clim Atmos Sci.  https://doi.org/10.1038/s41612-017-0004-6 Google Scholar
  21. Kang SM, Shin Y, Codron F (2018b) The partitioning of poleward energy transport response between the atmosphere and Ekman flux to prescribed surface forcing in a simplified GCM. Geosci Lett.  https://doi.org/10.1186/s40562-018-0124-9 Google Scholar
  22. Kay JE, Wall C, Yettella V, Medeiros B, Hannay C, Caldwell P, Bitz C (2016) Global climate impacts of fixing the southern ocean shortwave radiation bias in the community earth system model (CESM). J Clim 29:4617–4636.  https://doi.org/10.1175/JCLI-D-15-0358.1 CrossRefGoogle Scholar
  23. Lindzen RS, Hou AY (1988) Hadley circulations for zonally averaged heating centered off the equator. J Atmos Sci 45:2416–2427.  https://doi.org/10.1175/1520-0469(1988)045%3C2416:HCFZAH%3E2.0.CO;2 CrossRefGoogle Scholar
  24. Marshall J, Adcroft A, Hill C, Perelman L, Heisey C (1997a) A finite-volume, incompressible Navier Stokes model for studies of the ocean on parallel computers. J Geophys Res Oceans 102:5753–5766.  https://doi.org/10.1029/96JC02775 CrossRefGoogle Scholar
  25. Marshall J, Hill C, Perelman L, Adcroft A (1997b) Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling. J Geophys Res Oceans 102:5733–5752.  https://doi.org/10.1029/96JC02776 CrossRefGoogle Scholar
  26. Marshall J, Adcroft A, Campin JM, Hill C, White A (2004) Atmosphere-ocean modeling exploiting fluid isomorphisms. Mon Weather Rev 132:2882–2894.  https://doi.org/10.1175/MWR2835.1 CrossRefGoogle Scholar
  27. Marshall J, Donohoe A, Ferreira D, McGee D (2014) The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone. Clim Dyn 42:1967–1979.  https://doi.org/10.1007/s00382-013-1767-z CrossRefGoogle Scholar
  28. Miyama T, McCreary JP Jr, Jensen TG, Loschnigg J, Godfrey S, Ishida A (2003) Structure and dynamics of the Indian-Ocean cross-equatorial cell. Deep Sea Res II 50:2023–2047.  https://doi.org/10.1016/S0967-0645(03)00044-4 CrossRefGoogle Scholar
  29. Munk WH (1950) On the wind-driven ocean circulation. J Meteorol 7:79–93.  https://doi.org/10.1175/1520-0469(1950)007%3C0080:OTWDOC%3E2.0.CO;2 CrossRefGoogle Scholar
  30. Peixoto JP, Oort AH (1992) Physics of climate. American Institute of Physics, New YorkCrossRefGoogle Scholar
  31. Plumb RA, Hou AY (1992) The response of a zonally symmetric atmosphere to subtropical thermal forcing: threshold behavior. J Atmos Sci 49:1790–1799.  https://doi.org/10.1175/1520-0469(1992)049%3C1790:TROAZS%3E2.0.CO;2 CrossRefGoogle Scholar
  32. Ring MJ, Plumb RA (2008) The response of a simplified GCM to axisymmetric forcings: applicability of the fluctuation-dissipation theorem. J Atmos Sci 65:3880–3898.  https://doi.org/10.1175/2008JAS2773.1 CrossRefGoogle Scholar
  33. Rose BEJ, Armour KC, Battisti DS, Feldl N, Koll DDB (2014) The dependence of transient climate sensitivity and radiative feedbacks on the spatial pattern of ocean heat uptake. Geophys Res Lett 41:1071–1078.  https://doi.org/10.1002/2013GL058955 CrossRefGoogle Scholar
  34. Schneider T (2017) Feedback of atmosphere-ocean coupling on shifts of the intertropical convergence zone. Geophys Res Lett 44:11,644–11,653.  https://doi.org/10.1002/2017GL075817 CrossRefGoogle Scholar
  35. Schneider T, Bischoff T, Haug GH (2014) Migrations and dynamics of the intertropical convergence zone. Nature 513:45–53.  https://doi.org/10.1038/nature13636 CrossRefGoogle Scholar
  36. Seo J, Kang SM, Frierson DMW (2014) Sensitivity of intertropical convergence zone movement to the latitudinal position of thermal forcing. J Clim 27:3035–3042.  https://doi.org/10.1175/JCLI-D-13-00691.1 CrossRefGoogle Scholar
  37. Tomas RA, Deser C, Sun L (2016) The role of ocean heat transport in the global climate response to projected arctic sea ice loss. J Clim 29:6841–6859.  https://doi.org/10.1175/JCLI-D-15-0651.1 CrossRefGoogle Scholar
  38. Zelinka MD, Hartmann DL (2012) Climate feedbacks and their implications for poleward energy flux changes in a warming climate. J Clim 25:608–624.  https://doi.org/10.1175/JCLI-D-11-00096.1 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Massachusetts Institute of TechnologyCambridgeUSA
  2. 2.Joint Institute for the Study of the Atmosphere and OceanUniversity of WashingtonSeattleUSA

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