• Adam, O., , T. Bischoff, , and T. Schneider, 2016: Seasonal and interannual variations of the energy flux equator and ITCZ in present climate. Part I: Zonally averaged ITCZ position. J. Climate, doi:10.1175/JCLI-D-15-0512.1, in press.

    • Search Google Scholar
    • Export Citation
  • Ashfaq, M., , C. B. Skinner, , and N. S. Diffenbaugh, 2011: Influence of SST biases on future climate change projections. Climate Dyn., 36, 13031319, doi:10.1007/s00382-010-0875-2.

    • Search Google Scholar
    • Export Citation
  • Bischoff, T., , and T. Schneider, 2014: Energetic constraints on the position of the intertropical convergence zone. J. Climate, 27, 49374951, doi:10.1175/JCLI-D-13-00650.1.

    • Search Google Scholar
    • Export Citation
  • Bordoni, S., , and T. Schneider, 2008: Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nat. Geosci., 1, 515519, doi:10.1038/ngeo248.

    • Search Google Scholar
    • Export Citation
  • Borlace, S., , A. Santoso, , W. Cai, , and M. Collins, 2014: Extreme swings of the South Pacific convergence zone and the different types of El Niño events. J. Geophys. Res., 41, 46954703, doi:10.1002/2014GL060551.

    • Search Google Scholar
    • Export Citation
  • Broccoli, A. J., , K. A. Dahl, , and R. J. Stouffer, 2006: Response of the ITCZ to Northern Hemisphere cooling. Geophys. Res. Lett., 33, L01702, doi:10.1029/2005GL024546.

    • Search Google Scholar
    • Export Citation
  • Cai, W., and et al. , 2012: More extreme swings of the South Pacific convergence zone due to greenhouse warming. Nature, 488, 365369, doi:10.1038/nature11358.

    • Search Google Scholar
    • Export Citation
  • Chiang, J. C. H., , and C. M. Bitz, 2005: Influence of high latitude ice cover on the marine intertropical convergence zone. Climate Dyn., 25, 477496, doi:10.1007/s00382-005-0040-5.

    • Search Google Scholar
    • Export Citation
  • Chiang, J. C. H., , and A. R. Friedman, 2012: Extratropical cooling, interhemispheric thermal gradients, and tropical climate change. Annu. Rev. Earth Planet. Sci., 40, 383412, doi:10.1146/annurev-earth-042711-105545.

    • Search Google Scholar
    • Export Citation
  • Chou, C., , and J. D. Neelin, 2001: Mechanisms limiting the southward extent of the South American summer monsoon. Geophys. Res. Lett., 28, 24332436, doi:10.1029/2000GL012138.

    • Search Google Scholar
    • Export Citation
  • Chou, C., , and J. D. Neelin, 2003: Mechanisms limiting the northward extent of the northern summer monsoons over North America, Asia, and Africa. J. Climate, 16, 406425, doi:10.1175/1520-0442(2003)016<0406:MLTNEO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Cvijanovic, I., , and J. C. H. Chiang, 2013: Global energy budget changes to high latitude North Atlantic cooling and the tropical ITCZ response. Climate Dyn., 40, 14351452, doi:10.1007/s00382-012-1482-1.

    • Search Google Scholar
    • Export Citation
  • Dai, A., , and T. M. L. Wigley, 2000: Global patterns of ENSO-induced precipitation. Geophys. Res. Lett., 27, 12831286, doi:10.1029/1999GL011140.

    • Search Google Scholar
    • Export Citation
  • Donohoe, A., , J. Marshall, , D. Ferreira, , and D. McGee, 2013: The relationship between ITCZ location and cross equatorial atmospheric heat transport: From the seasonal cycle to the Last Glacial Maximum. J. Climate, 26, 35973618, doi:10.1175/JCLI-D-12-00467.1.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., 1995: On thermally direct circulations in moist atmospheres. J. Atmos. Sci., 52, 15291534, doi:10.1175/1520-0469(1995)052<1529:OTDCIM>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Fasullo, J. T., , and K. E. Trenberth, 2008: The annual cycle of the energy budget. Part II: Meridional structures and poleward transports. J. Climate, 21, 23132325, doi:10.1175/2007JCLI1936.1.

    • Search Google Scholar
    • Export Citation
  • Folland, C. K., , T. N. Palmer, , and D. E. Parker, 1986: Sahel rainfall and worldwide sea temperatures, 1901–85. Nature, 320, 602607, doi:10.1038/320602a0.

    • Search Google Scholar
    • Export Citation
  • Friedman, A. R., , Y.-T. Hwang, , J. C. Chiang, , and D. M. W. Frierson, 2013: Interhemispheric temperature asymmetry over the twentieth century and in future projections. J. Climate, 26, 54195433, doi:10.1175/JCLI-D-12-00525.1.

    • Search Google Scholar
    • Export Citation
  • Frierson, D. M. W., 2007: The dynamics of idealized convection schemes and their effect on the zonally averaged tropical circulation. J. Atmos. Sci., 64, 19591976, doi:10.1175/JAS3935.1.

    • Search Google Scholar
    • Export Citation
  • Frierson, D. M. W., , and Y.-T. Hwang, 2012: Extratropical influence on ITCZ shifts in slab ocean simulations of global warming. J. Climate, 25, 720733, doi:10.1175/JCLI-D-11-00116.1.

    • Search Google Scholar
    • Export Citation
  • Frierson, D. M. W., and et al. , 2013: Contribution of ocean overturning circulation to tropical rainfall peak in the Northern Hemisphere. Nat. Geosci., 6, 940944, doi:10.1038/ngeo1987.

    • Search Google Scholar
    • Export Citation
  • Giannini, A., , R. Saravanan, , and P. Chang, 2003: Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science, 302, 10271030, doi:10.1126/science.1089357.

    • Search Google Scholar
    • Export Citation
  • Harrison, E. F., , P. Minnis, , B. R. Barkstrom, , V. Ramanathan, , R. D. Cess, , and G. G. Gibson, 1990: Seasonal variation of cloud radiative forcing derived from the Earth Radiation Budget Experiment. J. Geophys. Res., 95, 18 68718 703, doi:10.1029/JD095iD11p18687.

    • Search Google Scholar
    • Export Citation
  • Held, I. M., , T. L. Delworth, , J. Lu, , K. L. Findell, , and T. R. Knutson, 2005: Simulation of Sahel drought in the 20th and 21st centuries. Proc. Natl. Acad. Sci. USA, 102, 17 89117 896, doi:10.1073/pnas.0509057102.

    • Search Google Scholar
    • Export Citation
  • Hill, S. A., , Y. Ming, , and I. M. Held, 2015: Mechanisms of forced tropical meridional energy flux change. J. Climate, 28, 17251742, doi:10.1175/JCLI-D-14-00165.1.

    • Search Google Scholar
    • Export Citation
  • Hwang, Y.-T., , and D. M. W. Frierson, 2013: Link between the double-intertropical convergence zone problem and cloud biases over the Southern Ocean. Proc. Natl. Acad. Sci. USA, 110, 49354940, doi:10.1073/pnas.1213302110.

    • Search Google Scholar
    • Export Citation
  • Hwang, Y.-T., , D. M. W. Frierson, , and S. M. Kang, 2013: Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century. Geophys. Res. Lett., 40, 28452850, doi:10.1002/grl.50502.

    • Search Google Scholar
    • Export Citation
  • Kang, S. M., , I. M. Held, , D. M. W. Frierson, , and M. Zhao, 2008: The response of the ITCZ to extratropical thermal forcing: Idealized slab-ocean experiments with a GCM. J. Climate, 21, 35213532, doi:10.1175/2007JCLI2146.1.

    • Search Google Scholar
    • Export Citation
  • Kang, S. M., , D. M. W. Frierson, , and I. M. Held, 2009: The tropical response to extratropical thermal forcing in an idealized GCM: The importance of radiative feedbacks and convective parameterization. J. Atmos. Sci., 66, 28122827, doi:10.1175/2009JAS2924.1.

    • Search Google Scholar
    • Export Citation
  • Klinger, B. A., , and J. Marotzke, 2000: Meridional heat transport by the subtropical cell. J. Phys. Oceanogr., 30, 696705, doi:10.1175/1520-0485(2000)030<0696:MHTBTS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Levine, X. J., , and T. Schneider, 2011: Response of the Hadley circulation to climate change in an aquaplanet GCM coupled to a simple representation of ocean heat transport. J. Atmos. Sci., 68, 769783, doi:10.1175/2010JAS3553.1.

    • Search Google Scholar
    • Export Citation
  • Lin, J.-L., 2007: The double-ITCZ problem in IPCC AR4 coupled GCMs: Ocean–atmosphere feedback analysis. J. Climate, 20, 44974525, doi:10.1175/JCLI4272.1.

    • Search Google Scholar
    • Export Citation
  • Lindzen, R. S., , and S. Nigam, 1987: On the role of sea surface temperature gradients in forcing low-level winds and convergence in the tropics. J. Atmos. Sci., 44, 24182436, doi:10.1175/1520-0469(1987)044<2418:OTROSS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Lindzen, R. S., , and A. Y. Hou, 1988: Hadley circulations for zonally averaged heating centered off the equator. J. Atmos. Sci., 45, 24162427, doi:10.1175/1520-0469(1988)045<2416:HCFZAH>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Liu, Z., , D. Ostrenga, , W. Teng, , and S. Kempler, 2012: Tropical Rainfall Measuring Mission (TRMM) precipitation data and services for research and applications. Bull. Amer. Meteor. Soc., 93, 13171325, doi:10.1175/BAMS-D-11-00152.1.

    • Search Google Scholar
    • Export Citation
  • Loeb, N. G., , B. A. Wielicki, , D. R. Doelling, , G. L. Smith, , D. F. Keyes, , S. Kato, , N. Manalo-Smith, , and T. Wong, 2009: Toward optimal closure of the Earth’s top-of-atmosphere radiation budget. J. Climate, 22, 748766, doi:10.1175/2008JCLI2637.1.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., , A. Donohoe, , D. Ferreira, , and D. McGee, 2014: The ocean’s role in setting the mean position of the inter-tropical convergence zone. Climate Dyn., 42, 19671979, doi:10.1007/s00382-013-1767-z.

    • Search Google Scholar
    • Export Citation
  • McGee, D., , A. Donohoe, , J. Marshall, , and D. Ferreira, 2014: Changes in ITCZ location and cross-equatorial heat transport at the Last Glacial Maximum, Heinrich Stadial 1, and the mid-Holocene. Earth Planet. Sci. Lett., 390, 6979, doi:10.1016/j.epsl.2013.12.043.

    • Search Google Scholar
    • Export Citation
  • Merlis, T. M., , T. Schneider, , S. Bordoni, , and I. Eisenman, 2013: Hadley circulation response to orbital precession. Part I: Aquaplanets. J. Climate, 26, 740753, doi:10.1175/JCLI-D-11-00716.1.

    • Search Google Scholar
    • Export Citation
  • NCAR Staff, Eds., 2014: The climate data guide: ERA-Interim: Derived components. NCAR/UCAR, accessed 2 January 2014. [Available online at https://climatedataguide.ucar.edu/climate-data/era-interim-derived-components.]

  • Neelin, J. D., 2007: Moist dynamics of tropical convection zones in monsoons, teleconnections, and global warming. The Global Circulation of the Atmosphere, T. Schneider and A. H. Sobel, Eds., Princeton University Press, 267–301.

  • Neelin, J. D., , and I. M. Held, 1987: Modeling tropical convergence based on the moist static energy budget. Mon. Wea. Rev., 115, 312, doi:10.1175/1520-0493(1987)115<0003:MTCBOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • O’Gorman, P. A., , and T. Schneider, 2008: The hydrological cycle over a wide range of climates simulated with an idealized GCM. J. Climate, 21, 38153832, doi:10.1175/2007JCLI2065.1.

    • Search Google Scholar
    • Export Citation
  • Peixoto, J. P., , and A. H. Oort, 1992: Physics of Climate. 1st ed. American Institute of Physics, 520 pp.

  • Privé, N. C., , and R. A. Plumb, 2007: Monsoon dynamics with interactive forcing. Part I: Axisymmetric studies. J. Atmos. Sci., 64, 14171430, doi:10.1175/JAS3916.1.

    • Search Google Scholar
    • Export Citation
  • Raymond, D. J., , S. Sessions, , A. H. Sobel, , and Z. Fuchs, 2009: The mechanics of gross moist stability. J. Adv. Model. Earth Syst., 1, 9, doi:10.3894/JAMES.2009.1.9.

    • Search Google Scholar
    • Export Citation
  • Rotstayn, L. D., , and U. Lohmann, 2002: Tropical rainfall trends and the indirect aerosol effect. J. Climate, 15, 21032116, doi:10.1175/1520-0442(2002)015<2103:TRTATI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Sachs, J. P., , D. Sachse, , R. H. Smittenberg, , Z. Zhang, , D. S. Battisti, , and S. Golubic, 2009: Southward movement of the Pacific intertropical convergence zone AD 1400–1850. Nat. Geosci., 2, 519525, doi:10.1038/ngeo554.

    • Search Google Scholar
    • Export Citation
  • Schneider, T., 2006: The general circulation of the atmosphere. Annu. Rev. Earth Planet. Sci., 34, 655688, doi:10.1146/annurev.earth.34.031405.125144.

    • Search Google Scholar
    • Export Citation
  • Schneider, T., , and S. Bordoni, 2008: Eddy-mediated regime transitions in the seasonal cycle of a Hadley circulation and implications for monsoon dynamics. J. Atmos. Sci., 65, 915934, doi:10.1175/2007JAS2415.1.

    • Search Google Scholar
    • Export Citation
  • Schneider, T., , K. L. Smith, , P. A. O’Gorman, , and C. C. Walker, 2006: A climatology of tropospheric zonal-mean water vapor fields and fluxes in isentropic coordinates. J. Climate, 19, 59185933, doi:10.1175/JCLI3931.1.

    • Search Google Scholar
    • Export Citation
  • Schneider, T., , P. A. O’Gorman, , and X. J. Levine, 2010: Water vapor and the dynamics of climate changes. Rev. Geophys., 48, RG3001, doi:10.1029/2009RG000302.

    • Search Google Scholar
    • Export Citation
  • Schneider, T., , T. Bischoff, , and G. H. Haug, 2014: Migrations and dynamics of the intertropical convergence zone. Nature, 513, 4553, doi:10.1038/nature13636.

    • Search Google Scholar
    • Export Citation
  • Sobel, A. H., 2007: Simple models of ensemble-averaged tropical precipitation and surface wind, given the sea surface temperature. The Global Circulation of the Atmosphere, T. Schneider and A. H. Sobel, Eds., Princeton University Press, 219–251.

  • Sobel, A. H., , and J. D. Neelin, 2006: The boundary layer contribution to intertropical convergence zones in the quasi-equilibrium tropical circulation model framework. Theor. Comput. Fluid Dyn., 20, 323350, doi:10.1007/s00162-006-0033-y.

    • Search Google Scholar
    • Export Citation
  • Stephens, G. L., , D. O’Brien, , P. J. Webster, , P. Pilewski, , S. Kato, , and J.-L. Li, 2015: The albedo of Earth. Rev. Geophys., 53, 141163, doi:10.1002/2014RG000449.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., , and J. M. Caron, 2001: Estimates of meridional atmosphere and ocean heat transports. J. Climate, 14, 34333443, doi:10.1175/1520-0442(2001)014<3433:EOMAAO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., , and D. P. Stepaniak, 2003: Covariability of components of poleward atmospheric energy transports on seasonal and interannual timescales. J. Climate, 16, 36913705, doi:10.1175/1520-0442(2003)016<3691:COCOPA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., , and J. T. Fasullo, 2008: An observational estimate of inferred ocean energy divergence. J. Phys. Oceanogr., 38, 984999, doi:10.1175/2007JPO3833.1.

    • Search Google Scholar
    • Export Citation
  • Vannière, B., , E. Guilyardi, , T. Toniazzo, , G. Madec, , and S. Woolnough, 2014: A systematic approach to identify the sources of tropical SST errors in coupled models using the adjustment of initialized experiments. Climate Dyn., 43, 22612282, doi:10.1007/s00382-014-2051-6.

    • Search Google Scholar
    • Export Citation
  • Voigt, A., , and T. A. Shaw, 2015: Circulation response to warming shaped by radiative changes of clouds and water vapour. Nat. Geosci., 8, 102106, doi:10.1038/ngeo2345.

    • Search Google Scholar
    • Export Citation
  • Waliser, D. E., , and R. C. J. Somerville, 1994: Preferred latitudes of the intertropical convergence zone. J. Atmos. Sci., 51, 16191639, doi:10.1175/1520-0469(1994)051<1619:PLOTIC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Walker, C. C., , and T. Schneider, 2006: Eddy influences on Hadley circulations: Simulations with an idealized GCM. J. Atmos. Sci., 63, 33333350, doi:10.1175/JAS3821.1.

    • Search Google Scholar
    • Export Citation
  • Xie, R., , and Y. Yang, 2014: Revisiting the latitude fluctuations of the eastern Pacific ITCZ during the central Pacific El Niño. Geophys. Res. Lett., 41, 77707776, doi:10.1002/2014GL061857.

    • Search Google Scholar
    • Export Citation
  • Yoshimori, M., , and A. J. Broccoli, 2008: Equilibrium response of an atmosphere–mixed layer ocean model to different radiative forcing agents: Global and zonal mean response. J. Climate, 21, 43994423, doi:10.1175/2008JCLI2172.1.

    • Search Google Scholar
    • Export Citation
  • Zhang, C., 2001: Double ITCZs. J. Geophys. Res., 106, 11 78511 792, doi:10.1029/2001JD900046.

  • Zhang, G. J., , and H. Wang, 2006: Toward mitigating the double ITCZ problem in NCAR CCSM3. Geophys. Res. Lett., 33, L06709, doi:10.1029/2005GL025229.

    • Search Google Scholar
    • Export Citation
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The Equatorial Energy Balance, ITCZ Position, and Double-ITCZ Bifurcations

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  • 1 California Institute of Technology, Pasadena, California
  • | 2 ETH Zurich, Zurich, Switzerland, and California Institute of Technology, Pasadena, California
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Abstract

The intertropical convergence zone (ITCZ) migrates north–south on seasonal and longer time scales. Previous studies have shown that the zonal-mean ITCZ displacement off the equator is negatively correlated with the energy flux across the equator; when the ITCZ lies in the Northern Hemisphere, energy flows southward across the equator, and vice versa. The hemisphere that exports energy across the equator is the hemisphere with more net energy input, and it is usually the warmer hemisphere. But states with a double ITCZ straddling the equator also occur, for example, seasonally over the eastern Pacific and frequently in climate models. Here it is shown how the ITCZ position is connected to the energy balance near the equator in a broad range of circumstances, including states with single and double ITCZs. Taylor expansion of the variation of the meridional energy flux around the equator leads to the conclusion that for large positive net energy input into the equatorial atmosphere, the ITCZ position depends linearly on the cross-equatorial energy flux. For small positive equatorial net energy input, the dependence of the ITCZ position on the cross-equatorial energy flux weakens to the third root. When the equatorial net energy input or its curvature become negative, a bifurcation to double-ITCZ states occurs. Simulations with an idealized aquaplanet general circulation model (GCM) confirm the quantitative adequacy of these relations. The results provide a framework for assessing and understanding causes of common climate model biases and for interpreting tropical precipitation changes, such as those evident in records of climates of the past.

Corresponding author address: Tobias Bischoff, Division of Geological and Planetary Sciences, 1200 E California Blvd., Pasadena, CA 91125. E-mail: tobias@caltech.edu

Abstract

The intertropical convergence zone (ITCZ) migrates north–south on seasonal and longer time scales. Previous studies have shown that the zonal-mean ITCZ displacement off the equator is negatively correlated with the energy flux across the equator; when the ITCZ lies in the Northern Hemisphere, energy flows southward across the equator, and vice versa. The hemisphere that exports energy across the equator is the hemisphere with more net energy input, and it is usually the warmer hemisphere. But states with a double ITCZ straddling the equator also occur, for example, seasonally over the eastern Pacific and frequently in climate models. Here it is shown how the ITCZ position is connected to the energy balance near the equator in a broad range of circumstances, including states with single and double ITCZs. Taylor expansion of the variation of the meridional energy flux around the equator leads to the conclusion that for large positive net energy input into the equatorial atmosphere, the ITCZ position depends linearly on the cross-equatorial energy flux. For small positive equatorial net energy input, the dependence of the ITCZ position on the cross-equatorial energy flux weakens to the third root. When the equatorial net energy input or its curvature become negative, a bifurcation to double-ITCZ states occurs. Simulations with an idealized aquaplanet general circulation model (GCM) confirm the quantitative adequacy of these relations. The results provide a framework for assessing and understanding causes of common climate model biases and for interpreting tropical precipitation changes, such as those evident in records of climates of the past.

Corresponding author address: Tobias Bischoff, Division of Geological and Planetary Sciences, 1200 E California Blvd., Pasadena, CA 91125. E-mail: tobias@caltech.edu
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