Editorial Type:
Article
Article Type:
Research Article

The Annual Cycle of Heat Content in the Peru Current Region

Ken Takahashi Department of Atmospheric Sciences, University of Washington, Seattle, Washington

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Print Publication:
01 Dec 2005
DOI:
https://doi.org/10.1175/JCLI3572.1
Page(s):
4937–4954
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Abstract

The relative importance of the processes responsible for the annual cycle in the upper-ocean heat content in the Peru Current, in the southeastern tropical Pacific, was diagnosed from an oceanic analysis dataset. It was found that the annual cycle of heat content is forced mainly by insolation. However, the ocean dynamical processes play an important role in producing different regional budget characteristics.

In a band 500 km from the coast of Peru, the annual heat content changes in this region are relatively large and can be approximated as sea surface temperature (SST) changes in a fixed-depth mixed layer. The annual cycle of the albedo associated with low-level clouds enhances the annual cycle in insolation, which explains the relatively strong annual cycle of heat content. These clouds, to a large extent, act as a feedback to SST, but a small additional forcing, which is proposed to be cold air advection in this paper, is needed to explain the fact that the maximum cloudiness leads the lowest SST by around a month. Ocean dynamics is important closer to the coast, where upwelling acts partly as damping of the heat content changes and forces it to peak earlier than farther offshore.

In a band farther to the southwest, locally wind-forced thermocline motions, which become shallower (deeper) in the warm (cool) season, partially cancel the effect of net surface heat fluxes, whose annual cycle is comparable to that in the region previously mentioned, producing a relatively small annual cycle of heat content. The local forcing appears to be associated with the annual meridional displacements of the South Pacific anticyclone. The annual cycle in SST is also relatively small, which is probably due to the changes in the temperature of the water entrained into the mixed layer associated with the thermocline motions, but also to a mixed layer deeper than that closer to the coast.

* Joint Institute for the Study of the Atmosphere and Ocean Contribution Number 1110

Corresponding author address: K. Takahashi, Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195. Email: ken@atmos.washington.edu

Abstract

The relative importance of the processes responsible for the annual cycle in the upper-ocean heat content in the Peru Current, in the southeastern tropical Pacific, was diagnosed from an oceanic analysis dataset. It was found that the annual cycle of heat content is forced mainly by insolation. However, the ocean dynamical processes play an important role in producing different regional budget characteristics.

In a band 500 km from the coast of Peru, the annual heat content changes in this region are relatively large and can be approximated as sea surface temperature (SST) changes in a fixed-depth mixed layer. The annual cycle of the albedo associated with low-level clouds enhances the annual cycle in insolation, which explains the relatively strong annual cycle of heat content. These clouds, to a large extent, act as a feedback to SST, but a small additional forcing, which is proposed to be cold air advection in this paper, is needed to explain the fact that the maximum cloudiness leads the lowest SST by around a month. Ocean dynamics is important closer to the coast, where upwelling acts partly as damping of the heat content changes and forces it to peak earlier than farther offshore.

In a band farther to the southwest, locally wind-forced thermocline motions, which become shallower (deeper) in the warm (cool) season, partially cancel the effect of net surface heat fluxes, whose annual cycle is comparable to that in the region previously mentioned, producing a relatively small annual cycle of heat content. The local forcing appears to be associated with the annual meridional displacements of the South Pacific anticyclone. The annual cycle in SST is also relatively small, which is probably due to the changes in the temperature of the water entrained into the mixed layer associated with the thermocline motions, but also to a mixed layer deeper than that closer to the coast.

* Joint Institute for the Study of the Atmosphere and Ocean Contribution Number 1110

Corresponding author address: K. Takahashi, Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195. Email: ken@atmos.washington.edu

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  • Behringer, D. W., M. Ji, and A. Leetmaa, 1998: An improved coupled model for ENSO prediction and implications of ocean initialization. Part I: The ocean data assimilation system. Mon. Wea. Rev., 126 , 1013–1021.

    • Search Google Scholar
    • Export Citation

  • Blanco, J. L., A. C. Thomas, M-E. Carr, and P. T. Strub, 2001: Seasonal climatology of hydrographic conditions in the upwelling region off northern Chile. J. Geophys. Res., 106 , 11451–11467.

    • Search Google Scholar
    • Export Citation

  • Carton, J. A., G. Chepurin, X. Cao, and B. Giese, 2000: A simple ocean data assimilation analysis of the global upper ocean 1950–95. Part I: Methodology. J. Phys. Oceanogr., 30 , 294–309.

    • Search Google Scholar
    • Export Citation

  • Davey, M. K., and Coauthors, 2002: STOIC: A study of coupled model climatology and variability in tropical ocean regions. Climate Dyn., 18 , 403–420.

    • Search Google Scholar
    • Export Citation

  • Giese, B. S., and J. A. Carton, 1994: The seasonal cycle in a coupled ocean–atmosphere model. J. Climate, 7 , 1208–1217.

  • Gordon, C. T., A. Rosati, and R. Gudgel, 2000: Tropical sensitivity of a coupled model to specified ISCCP low clouds. J. Climate, 13 , 2239–2260.

    • Search Google Scholar
    • Export Citation

  • Hellerman, S., and M. Rosenstein, 1983: Normal monthly wind stress over the World Ocean with error estimates. J. Phys. Oceanogr., 13 , 1093–1104.

    • Search Google Scholar
    • Export Citation

  • Ji, M., A. Leetmaa, and J. Derber, 1995: An ocean analysis system for seasonal to interannual climate studies. Mon. Wea. Rev., 123 , 460–481.

    • Search Google Scholar
    • Export Citation

  • Josey, S. A., E. C. Kent, and P. K. Taylor, 1999: The Southampton Oceanography Centre (SOC) Ocean–Atmosphere Heat, Momentum and Freshwater Flux Atlas. Southampton Oceanography Centre, 30 pp. plus figures.

    • Search Google Scholar
    • Export Citation

  • Klein, S. A., 1997: Synoptic variability of low-cloud properties and meteorological parameters in the subtropical trade wind boundary layer. J. Climate, 10 , 2018–2039.

    • Search Google Scholar
    • Export Citation

  • Klein, S. A., and D. L. Hartmann, 1993: The seasonal cycle of low stratiform clouds. J. Climate, 6 , 1587–1606.

  • Kubota, M., N. Iwasaka, S. Kizu, M. Konda, and K. Kutsuwada, 2002: Japanese ocean flux data sets with use of remote sensing observations (J-OFURO). J. Oceanogr., 58 , 213–225.

    • Search Google Scholar
    • Export Citation

  • Latif, M., and Coauthors, 2001: ENSIP: The El Niño simulation intercomparison project. Climate Dyn., 18 , 255–276.

  • Lukas, R., 1986: The termination of the Equatorial Undercurrent in the eastern Pacific. Progress in Oceanography, Vol. 16, Pergamon, 63–90.

  • Mechoso, C. R., and Coauthors, 1995: The seasonal cycle over the tropical Pacific in coupled ocean–atmosphere general circulation models. Mon. Wea. Rev., 123 , 2825–2838.

    • Search Google Scholar
    • Export Citation

  • Mitchell, T. P., and J. M. Wallace, 1992: The annual cycle in equatorial convection and sea surface temperature. J. Climate, 5 , 1140–1156.

    • Search Google Scholar
    • Export Citation

  • Oberhuber, J. M., 1988: An atlas based on the “COADS” data set: The budgets of heat, buoyancy and turbulent kinetic energy at the surface of the global ocean. Rep. 15, Max-Planck-Institute für Meteorologie, Hamburg, Germany, 20 pp.

  • Philander, S. G. H., and Pacanowski, 1981: The oceanic response to cross-equatorial winds (with application to coastal upwelling in low latitudes). Tellus, 33 , 201–210.

    • Search Google Scholar
    • Export Citation

  • Philander, S. G. H., and J-H. Yoon, 1982: Eastern boundary currents and coastal upwelling. J. Phys. Oceanogr., 12 , 862–879.

  • Philander, S. G. H., D. Gu, D. Halpern, G. Lambert, N-C. Lau, T. Li, and R. C. Pacanowski, 1996: Why the ITCZ is mostly north of the equator. J. Climate, 9 , 2958–2972.

    • Search Google Scholar
    • Export Citation

  • Rossow, W. B., and Y-C. Zhang, 1995: Calculation of surface and top of atmosphere radiative fluxes from physical quantities based on ISCCP data sets: 2. Validation and first results. J. Geophys. Res., 100 , 1167–1197.

    • Search Google Scholar
    • Export Citation

  • Seager, R., R. Murtugudde, N. Naik, A. Clement, N. Gordon, and J. Miller, 2003: Air–sea interaction and the seasonal cycle of the subtropical anticyclones. J. Climate, 16 , 1948–1966.

    • Search Google Scholar
    • Export Citation

  • Stammer, D., 1998: On eddy characteristics, eddy transports, and mean flow properties. J. Phys. Oceanogr., 28 , 727–739.

  • Stephens, C., J. I. Antonov, T. P. Boyer, M. E. Conkright, R. A. Locarnini, T. D. O’Brien, and H. E. Garcia, 2002: Temperature. Vol. 1, World Ocean Atlas 2001, S. Levitus, Ed., NOAA Atlas NESDIS 49, 167 pp.

  • Strub, P. T., J. M. Mesias, V. Montecino, J. Ruttlant, and S. Salinas, 1998: Coastal ocean circulation off western South America. The Sea, A. R. Robinson and K. H. Brink, Eds., Ocean Engineering Science, Vol. 10, Wiley and Sons, 273–313.

    • Search Google Scholar
    • Export Citation

  • Wang, B., R. Wu, and R. Lukas, 2000: Annual adjustment of the thermocline in the tropical Pacific Ocean. J. Climate, 13 , 596–616.

  • Warren, S. G., C. J. Hahn, J. London, R. M. Chervin, and R. L. Jenne, 1986: Global distribution of total cloud cover and cloud type amounts over the ocean. NCAR Tech. Note NCAR/TN-317+STR, National Center for Atmospheric Research, Boulder, CO, 42 pp. plus 170 maps.

  • Wyrtki, K., 1964: The thermal structure of the Eastern Pacific Ocean. Dtsch. Hydrogr. Z. Ergänzungsheft, A6 , 1–84.

  • Zhang, Y-C., W. B. Rossow, and A. A. Lacis, 1995: Calculation of surface and top of atmosphere radiative fluxes from physical quantities based on ISCCP data sets: 1. Method and sensitivity to input data uncertainties. J. Geophys. Res., 100 , 1149–1165.

    • Search Google Scholar
    • Export Citation

  • Zuta, S., and O. Guillén, 1970: Oceanografía de las aguas costeras del Perú. Bol. Inst. Mar. Perú, 2 , 157–324.

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