Surface Layer Temperature Balance in the Equatorial Pacific during the 1997–98 El Niño and 1998–99 La Niña

Weimin Wang School of Oceanography, University of Washington, Seattle, Washington

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Michael J. McPhaden NOAA/Pacific Marine Environmental Laboratory, Seattle, Washington

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Abstract

The surface layer temperature balance in the equatorial Pacific has been examined for the period of 1996–99 by using data obtained from Tropical Atmosphere–Ocean buoy array at four locations along the equator, namely, 165°E, 170°W, 140°W, and 110°W. Time rate change of SST, horizontal temperature advection, and heat fluxes at the sea surface are estimated directly from the data. Vertical fluxes of heat out of the base of the mixed layer, related to changes in vertical mixing and upwelling, are calculated as a residual. Results indicate that all terms in the temperature balance contributed to SST variations during different stages of the 1997–98 El Niño and the 1998–99 La Niña. Zonal advection was particularly important during the onset of the El Niño in the central Pacific. The inferred vertical heat flux out of the base of the mixed layer was important most of the time, and was especially pronounced in the eastern Pacific during the termination phase of the El Niño. Meridional advection due to eddies was a negative feedback on SST change in the eastern Pacific during both the El Niño and La Niña, tending to counteract the development of warm and cold anomalies. Likewise, the net surface heat flux generally represented a negative feedback, tending to damp SST anomalies created by ocean dynamical processes. The relevance of these results to recent theoretical developments concerning ENSO timescale physical processes is discussed.

Corresponding author address: Michael J. McPhaden, NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115. Email: mcphaden@pmel.noaa.gov

Abstract

The surface layer temperature balance in the equatorial Pacific has been examined for the period of 1996–99 by using data obtained from Tropical Atmosphere–Ocean buoy array at four locations along the equator, namely, 165°E, 170°W, 140°W, and 110°W. Time rate change of SST, horizontal temperature advection, and heat fluxes at the sea surface are estimated directly from the data. Vertical fluxes of heat out of the base of the mixed layer, related to changes in vertical mixing and upwelling, are calculated as a residual. Results indicate that all terms in the temperature balance contributed to SST variations during different stages of the 1997–98 El Niño and the 1998–99 La Niña. Zonal advection was particularly important during the onset of the El Niño in the central Pacific. The inferred vertical heat flux out of the base of the mixed layer was important most of the time, and was especially pronounced in the eastern Pacific during the termination phase of the El Niño. Meridional advection due to eddies was a negative feedback on SST change in the eastern Pacific during both the El Niño and La Niña, tending to counteract the development of warm and cold anomalies. Likewise, the net surface heat flux generally represented a negative feedback, tending to damp SST anomalies created by ocean dynamical processes. The relevance of these results to recent theoretical developments concerning ENSO timescale physical processes is discussed.

Corresponding author address: Michael J. McPhaden, NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115. Email: mcphaden@pmel.noaa.gov

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  • Battisti, D. S., 1988: Dynamics and thermodynamics of a warming event in a coupled atmosphere–ocean model. J. Atmos. Sci, 45 , 28892919.

    • Search Google Scholar
    • Export Citation
  • Baturin, N. G., and P. P. Niiler, 1997: Effects of instability waves in the mixed layer of the equatorial Pacific. J. Geophys. Res, 102 , 2777127793.

    • Search Google Scholar
    • Export Citation
  • Boulanger, J-P., and C. Menkes, 1999: Long equatorial wave reflection in the Pacific Ocean from TOPEX/Poseidon data during the 1992–1998 period. Climate Dyn, 15 , 205225.

    • Search Google Scholar
    • Export Citation
  • Boulanger, J-P., and C. Menkes, 2001: The Trident Pacific model, Part 2: Role of long equatorial wave reflection on sea surface temperature anomalies during 1993–98 TOPEX/Poseidon period. Climate Dyn., 17, 175–186.

    • Search Google Scholar
    • Export Citation
  • Bryden, H. L., and E. L. Brady, 1989: Lateral mixing in the equatorial Pacific Ocean. J. Mar. Res, 47 , 5579.

  • Chavez, F. P., P. G. Strutton, and M. J. McPhaden, 1998: Biological–physical coupling in the central equatorial Pacific during the onset of the 1997–98 El Niño. Geophys. Res. Lett, 25 , 35433546.

    • Search Google Scholar
    • Export Citation
  • Chen, D., M. A. Cane, S. E. Zebiak, and A. Kaplan, 1998: The impact of sea level data assimilation on the Lamont model prediction of the 1997/98 El Niño. Geophys. Res. Lett, 25 , 28372840.

    • Search Google Scholar
    • Export Citation
  • Chen, D., M. A. Cane, and S. E. Zebiak, 1999: The impact of NSCAT winds on predicting the 1997/1998 El Niño: A case study with the Lamont–Doherty Earth Observatory model. J. Geophys. Res, 104 , 1132111327.

    • Search Google Scholar
    • Export Citation
  • Chertock, B., R. Frouin, and R. C. J. Somerville, 1991: Global monitoring of net solar irradiance at the ocean surface: Climatological variability and 1982–83 El Niño. J. Climate, 4 , 639650.

    • Search Google Scholar
    • Export Citation
  • Clark, A. J., J. Wang, and S. V. Gorder, 2000: A simple warm-pool displacement ENSO model. J. Phys. Oceanogr, 30 , 16791691.

  • Clark, N. E., L. Eber, R. M. Laurs, J. A. Renner, and J. F. T. Saur, 1974: Heat exchange between ocean and atmosphere in the eastern North Pacific for 1961–71. NOAA Tech. Rep. NMFS SSRF-682, U.S. Department of Commerce, Washington, D.C.

    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., and W. S. Kessler, 2001: Seasonal and interannual modulation of mixed layer variability at 0°, 110°W. Deep-Sea Res. I, in press.

    • Search Google Scholar
    • Export Citation
  • da Silva, A. M., C. C. Young, and S. Levitus, 1994: Algorithms and Procedures. Vol. 1, Atlas of Surface Marine Data 1994, NOAA Atlas NESDIS 6, 83 pp.

    • Search Google Scholar
    • Export Citation
  • Davey, M. K., and D. L. T. Anderson, 1998: A comparison of the 1997/98 El Niño with other such events. Weather, 53 , 295302.

  • Fairall, C. W., E. F. Bradley, D. P. Rogers, J. B. Edson, and G. S. Young, 1996: Bulk parameterization of air–sea fluxes for Tropical Ocean–Global Atmosphere Coupled–Ocean Atmosphere Response Experiment algorithm. J. Geophys. Res, 101 , 37473764.

    • Search Google Scholar
    • Export Citation
  • Hansen, D., and C. Paul, 1984: Genesis and effects of long waves in the equatorial Pacific. J. Geophys. Res, 89 , 1043110440.

  • Hayes, S. P., L. J. Mangum, J. Picaut, A. Sumi, and K. Takeuchi, 1991: TOGA TAO: A moored array for real-time measurements in the tropical Pacific Ocean. Bull. Amer. Meteor. Soc, 72 , 339347.

    • Search Google Scholar
    • Export Citation
  • Jin, F-F., 1997: An equatorial ocean recharge paradigm for ENSO. Part I: Conceptual model. J. Atmos. Sci, 54 , 811829.

  • Johnson, G. C., M. J. McPhaden, G. D. Rowe, and K. E. McTaggart, 2000: Upper equatorial Pacific Ocean current and salinity variability during the 1996–1998 El Niño–La Niña cycle. J. Geophys. Res, 105 , 10371053.

    • Search Google Scholar
    • Export Citation
  • Kessler, W. S., and R. Kleeman, 2000: Rectification of the Madden–Julian oscillation into the ENSO cycle. J. Climate, 13 , 35603575.

    • Search Google Scholar
    • Export Citation
  • Lagerloef, G. S. E., G. T. Mitchum, R. B. Lukas, and P. P. Niiler, 1999: Tropical Pacific near-surface currents estimated from altimeter, wind and drifter data,. J. Geophys. Res, 104 , 2331323326.

    • Search Google Scholar
    • Export Citation
  • Larkin, N. K., and D. E. Harrison, 2001: Tropical Pacific ENSO cold events, 1946–1995: SST, SLP, and surface wind composite anomaly patterns. J. Climate, in press.

    • Search Google Scholar
    • Export Citation
  • Legler, D. M., 1991: Producing surface wind products for oceanographers. Proc. IGOSS/IOC Ocean Products Workshop, Tokyo, Japan, Intergovernmental Oceanographic Commission, 59–76.

    • Search Google Scholar
    • Export Citation
  • Liu, W. T., A. Zhang, and J. K. B. Bishop, 1994: Evaporation and solar irradiance as regulators of sea surface temperature in annual and interannual changes. J. Geophys. Res, 99 , 1262312637.

    • Search Google Scholar
    • Export Citation
  • McPhaden, M. J., 1999: Genesis and evolution of the 1997–98 El Niño. Science, 283 , 950954.

  • McPhaden, M. J., and S. P. Hayes, 1990: Variability in the eastern equatorial Pacific during 1986–1988. J. Geophys. Res, 95 , 1319513208.

    • Search Google Scholar
    • Export Citation
  • McPhaden, M. J., and X. Yu, 1999: Equatorial waves and the 1997–98 El Niño. Geophys. Res. Lett, 26 , 29612964.

  • McPhaden, M. J., and Coauthors. . 1998: The Tropical Ocean Global Atmosphere (TOGA) observing system: A decade of progress. J. Geophys. Res, 103 , 1416914240.

    • Search Google Scholar
    • Export Citation
  • Meinen, C. S., and M. J. McPhaden, 2000: Observations of warm water volume changes in the equatorial Pacific and their relationship to El Niño and La Niña. J. Climate, 13 , 35513559.

    • Search Google Scholar
    • Export Citation
  • Meinen, C. S., and M. J. McPhaden, 2001: Warm water displacements in the equatorial Pacific during 1993–1999. J. Phys. Oceanogr., 31, 1324–1345.

    • Search Google Scholar
    • Export Citation
  • Meinen, C. S., M. J. McPhaden, and G. C. Johnson, 2001: Vertical velocities and transports in the equatorial Pacific during 1993–1999. J. Phys. Oceanogr., in press.

    • Search Google Scholar
    • Export Citation
  • Moore, A. M., and R. Kleeman, 1999: Stochastic forcing of ENSO by the intraseasonal oscillation. J. Climate, 12 , 11991220.

  • Oberhuber, J. M., E. Roeckner, M. Christoph, M. Esch, and M. Latif, 1998: Predicting the '97 El Niño event with a global climate model. Geophys. Res. Lett, 25 , 22732276.

    • Search Google Scholar
    • Export Citation
  • Payne, R. E., 1972: Albedo of the sea surface. J. Atmos. Sci, 29 , 959970.

  • Philander, S. G. H., and Coauthors. . 1985: Long waves in the equatorial Pacific Ocean. Eos, Trans. Amer. Geophys. Union, 66 , 154.

  • Picaut, J., and T. Delcroix, 1995: Equatorial wave sequence associated with warm pool displacements during the 1986–1989 El Niño–La Niña. J. Geophys. Res, 100 , 1839318408.

    • Search Google Scholar
    • Export Citation
  • Picaut, J., F. Masia, and Y. du Penhoat, 1997: An advective–reflective conceptual model for the oscillatory nature of ENSO. Science, 277 , 663666.

    • Search Google Scholar
    • Export Citation
  • Reede, R., 1977: On estimating insolation over the ocean. J. Phys. Oceanogr, 7 , 482485.

  • Reynolds, R. W., and T. M. Smith, 1994: Improved global sea surface temperature analysis using optimum interpolation. J. Climate, 7 , 929948.

    • Search Google Scholar
    • Export Citation
  • Schopf, P. S., and M. J. Suarez, 1988: Vacillations in a coupled ocean–atmosphere model. J. Atmos. Sci, 45 , 549566.

  • Slingo, J., 1998: The 1997/98 El Niño. Weather, 53 , 274281.

  • Sprintall, J., and M. Tomczak, 1992: Evidence of the barrier layer in the surface layer of the Tropics. J. Geophys. Res, 97 , 73057316.

    • Search Google Scholar
    • Export Citation
  • Takayabu, Y. N., T. Iguchi, M. Kachi, A. Shibata, and H. Kanzawa, 1999: Abrupt termination of the 1997–98 El Niño in response to a Madden–Julian oscillation. Nature, 402 , 279282.

    • Search Google Scholar
    • Export Citation
  • Vialard, J., C. Menkes, J-P. Boulanger, P. Delecluse, E. Guilyardi, M. J. McPhaden, and G. Madec, 2001: A model study of oceanic mechanisms affection equatorial Pacific sea surface temperature during the 1997–98 El Niño. J. Phys. Oceanogr, 31 , 16491675.

    • Search Google Scholar
    • Export Citation
  • Waliser, D. E., B. Blanke, J. D. Neelin, and C. Gautier, 1994: Shortwave feedbacks and El Niño–Southern Oscillation: Forced ocean and coupled ocean–atmosphere experiments. J. Geophys. Res, 99 , 2510925125.

    • Search Google Scholar
    • Export Citation
  • Wang, C., and R. H. Weisberg, 2000: The 1997–98 El Niño evolution relative to previous El Niño events. J. Climate, 13 , 488501.

  • Wang, W., and M. J. McPhaden, 1999: The surface layer heat balance in the equatorial Pacific ocean. Part I: Mean seasonal cycle. J. Phys. Oceanogr, 29 , 18121831.

    • Search Google Scholar
    • Export Citation
  • Wang, W., and M. J. McPhaden, 2000: The surface layer heat balance in the equatorial Pacific ocean. Part II: Interannual variability. J. Phys. Oceanogr, 30 , 29893008.

    • Search Google Scholar
    • Export Citation
  • Wang, W., and M. J. McPhaden, 2001: What is the mean seasonal cycle of surface heat flux in the equatorial Pacific? J. Geophys. Res., 106, 837–857.

    • Search Google Scholar
    • Export Citation
  • Zhang, G. J., and M. J. McPhaden, 1995: The relationship between sea surface temperature and latent heat flux in the equatorial Pacific. J. Climate, 8 , 589605.

    • Search Google Scholar
    • Export Citation
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