• Anderson, K., and Coauthors, 2004: The RED experiment: An assessment of boundary layer effects in a trade winds regime on microwave and infrared propagation over the sea. Bull. Amer. Meteor. Soc., 85, 13551365.

    • Search Google Scholar
    • Export Citation
  • Andreas, E. L, 1995: The temperature of evaporating sea spray droplets. J. Atmos. Sci., 52, 852862.

  • Andreas, E. L, 2011: Fallacies of the enthalpy transfer coefficient over the ocean in high winds. J. Atmos. Sci., 68, 14351445.

  • Andreas, E. L, , and K. A. Emanuel, 2001: Effects of sea spray on tropical cyclone intensity. J. Atmos. Sci., 58, 37413751.

  • Burns, S. P., and Coauthors, 2000: Comparisons of aircraft, ship, and buoy radiation and SST measurements from TOGA COARE. J. Geophys. Res., 105, 15 62715 652.

    • Search Google Scholar
    • Export Citation
  • Donlon, C. J., , P. J. Minnett, , C. Gentemann, , T. Nightingale, , J. Barton, , B. Ward, , and M. J. Murray, 2002: Toward improved validation of satellite sea surface skin temperature measurements for climatic research. J. Climate, 15, 353369.

    • Search Google Scholar
    • Export Citation
  • Edson, J. B., and Coauthors, 2007: The Coupled Boundary Layers and Air–Sea Transfer experiment in low winds. Bull. Amer. Meteor. Soc., 88, 341356.

    • Search Google Scholar
    • Export Citation
  • Fairall, C. W., and Coauthors, 2006: Turbulent bulk transfer coefficients and ozone deposition velocity in the International Consortium for Atmospheric Research into Transport and Transformation. J. Geophys. Res., 111, D23S20, doi:10.1029/2006JD007597.

    • Search Google Scholar
    • Export Citation
  • Grachev, A., , C. Fairall, , J. Hare, , J. Edson, , and S. Miller, 2003: Wind stress vector over ocean waves. J. Phys. Oceanogr., 33, 24082429.

    • Search Google Scholar
    • Export Citation
  • Hagan, D., , D. Rogers, , C. Friehe, , R. Weller, , and E. Walsh, 1997: Aircraft observations of sea surface temperature variability in the tropical Pacific. J. Geophys. Res., 102, 15 73315 747.

    • Search Google Scholar
    • Export Citation
  • Kalogiros, J., , and Q. Wang, 2011: Aircraft observations of sea-surface turbulent fluxes near the California coast. Bound.-Layer Meteor., 139, 283306.

    • Search Google Scholar
    • Export Citation
  • Katsaros, K., 1980: Radiative sensing of sea surface temperature. Air-Sea Interaction: Instruments and Methods, F. Dobson, L. Hasse, and R. Davis, Eds., Plenum Press, 293–317

  • Katsaros, K., , and A. V. Soloviev, 2004: Vanishing horizontal sea surface temperature gradients at low wind speeds. Bound.-Layer Meteor., 112, 381396.

    • Search Google Scholar
    • Export Citation
  • Katsaros, K., , A. V. Soloviev, , R. H. Weisberg, , and M. E. Luther, 2005: Reduced horizontal sea surface temperature gradients under conditions of clear skies and weak winds. Bound.-Layer Meteor., 116, 175185.

    • Search Google Scholar
    • Export Citation
  • Lenschow, D. H., 1970: Airplane measurements of planetary boundary layer structure. J. Appl. Meteor., 9, 874884.

  • Lenschow, D. H., , and J. Sun, 2007: The spectral composition of fluxes and variances over land and sea out to the mesoscale. Bound.-Layer Meteor., 125, 6384.

    • Search Google Scholar
    • Export Citation
  • Mahrt, L., 1991: Eddy asymmetry in the sheared heated boundary layer. J. Atmos. Sci., 48, 472492.

  • Mahrt, L., , and D. Khelif, 2010: Heat fluxes over weak SST heterogeneity. J. Geophys. Res., 115, D11103, doi:10.1029/2009JD013161.

  • Mahrt, L., , D. Vickers, , J. Edson, , J. Sun, , J. Højstrup, , J. Hare, , and J. M. Wilczak, 1998: Heat flux in the coastal zone. Bound.-Layer Meteor., 86, 421446.

    • Search Google Scholar
    • Export Citation
  • Mahrt, L., , D. Vickers, , J. Sun, , T. L. Crawford, , G. Crescenti, , and P. Frederickson, 2001: Surface stress in offshore flow and quasi-frictional decoupling. J. Geophys. Res., 106, 20 62920 639.

    • Search Google Scholar
    • Export Citation
  • Marmorino, G. O., , and G. B. Smith, 2005: Bright and dark ocean whitecaps observed in the infrared. Geophys. Res. Lett., 32, L11604, doi:10.1029/2005GL023176.

    • Search Google Scholar
    • Export Citation
  • Marmorino, G. O., , G. B. Smith, , and G. J. Lindemann, 2004: Infrared imagery of ocean internal waves. Geophys. Res. Lett., 31, L11309, doi:10.1029/2004GL020152.

    • Search Google Scholar
    • Export Citation
  • Raga, G. B., , and S. Abarca, 2007: On the parameterization of turbulent fluxes over the tropical eastern Pacific. Atmos. Chem. Phys., 7, 635643.

    • Search Google Scholar
    • Export Citation
  • Smedman, A.-S., , U. Högström, , J. Hunt, , and E. Sahlée, 2007a: Heat/mass transfer in the slightly unstable atmospheric surface layer. Quart. J. Roy. Meteor. Soc., 133, 3751.

    • Search Google Scholar
    • Export Citation
  • Smedman, A.-S., , U. Högström, , E. Sahlée, , and C. Johansson, 2007b: Critical re-evaluation of the bulk transfer coefficient for sensible heat over the ocean during unstable and neutral conditions. Quart. J. Roy. Meteor. Soc., 133, 227250.

    • Search Google Scholar
    • Export Citation
  • Soloviev, A., , and R. Lukas, 2006: The Near-Surface Layer of the Ocean: Structure, Dynamics and Applications. Springer, 572 pp.

  • Sun, J., , J. F. Howell, , S. K. Esbensen, , L. Mahrt, , C. M. Greb, , R. Grossman, , and M. A. LeMone, 1996: Scale dependence of air–sea fluxes over the western equatorial Pacific. J. Atmos. Sci., 53, 29973012.

    • Search Google Scholar
    • Export Citation
  • Sun, J., , D. Vandemark, , L. Mahrt, , D. Vickers, , T. Crawford, , and C. Vogel, 2001: Momentum transfer over the coastal zone. J. Geophys. Res., 106, 12 43712 488.

    • Search Google Scholar
    • Export Citation
  • Vickers, D., , and L. Mahrt, 2006: Evaluation of the air-sea bulk formula and sea-surface temperature variability. J. Geophys. Res., 111, C05002, doi:10.1029/2005JC003323.

    • Search Google Scholar
    • Export Citation
  • Walsh, E. J., 1998: Coupling of internal waves on the main thermocline to the diurnal surface layer and sea surface temperature during the Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. J. Geophys. Res., 103, 12 61312 628.

    • Search Google Scholar
    • Export Citation
  • Wilczak, J., 1984: Large-scale eddies in the unstably stratified atmospheric surface layer. Part I: Velocity and temperature structure. J. Atmos. Sci., 41, 35373550.

    • Search Google Scholar
    • Export Citation
  • Zappa, C. J., , W. E. Asher, , A. T. Jessup, , J. Klinke, , and S. R. Long, 2004: Microbreaking and the enhancement of air-water transfer velocity. J. Geophys. Res., 109, C08S16, doi:10.1029/2003JC001897.

    • Search Google Scholar
    • Export Citation
  • Zeng, X., , M. Zhao, , and R. E. Dickinson, 1998: Intercomparison of bulk aerodynamic algorithms for the computation of sea surface fluxes using TOGA COARE and TAO data. J. Climate, 11, 26282644.

    • Search Google Scholar
    • Export Citation
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Sensible Heat Flux in Near-Neutral Conditions over the Sea

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  • 1 NorthWest Research Associates (Seattle Division), Corvallis, Oregon
  • | 2 CEOAS, Oregon State University, Corvallis, Oregon
  • | 3 NorthWest Research Associates (Seattle Division), Lebanon, New Hampshire
  • | 4 Department of Mechanical and Aerospace Engineering, University of California, Irvine, Irvine, California
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Abstract

The variation of the sea surface sensible heat flux is investigated using data from the Gulf of Tehuantepec Experiment (GOTEX) and from eight additional aircraft datasets representing a variety of surface conditions. This analysis focuses on near-neutral conditions because these conditions are common over the sea and are normally neglected, partly because of uncertain reliability of measurements of the small air–sea temperature difference. For all of the datasets, upward heat flux is observed for slightly stable conditions. The frequency of this “countergradient” heat flux increases with increasing wind speed and is possibly related to sea spray or microscale variations of surface temperature on the wave scale. Upward area-averaged sensible heat flux for slightly stable conditions can also be generated by mesoscale heterogeneity of the sea surface temperature (SST). Significant measurement errors cannot be ruled out.

The countergradient heat flux for weakly stable conditions is least systematic for weaker winds, even though it occurs with weak winds in all of the datasets. In an effort to reduce offset errors and different SST processing and calibration procedures among field programs, the authors adjusted the SST in each field program to minimize the countergradient flux for weak winds. With or without this adjustment for the combined dataset, the extent of the upward heat flux for weakly stable conditions increases with increasing wind speed.

Corresponding author address: Larry Mahrt, 2171 NW Kari Pl., Corvallis, OR 97330. E-mail: mahrt@nwra.com

Abstract

The variation of the sea surface sensible heat flux is investigated using data from the Gulf of Tehuantepec Experiment (GOTEX) and from eight additional aircraft datasets representing a variety of surface conditions. This analysis focuses on near-neutral conditions because these conditions are common over the sea and are normally neglected, partly because of uncertain reliability of measurements of the small air–sea temperature difference. For all of the datasets, upward heat flux is observed for slightly stable conditions. The frequency of this “countergradient” heat flux increases with increasing wind speed and is possibly related to sea spray or microscale variations of surface temperature on the wave scale. Upward area-averaged sensible heat flux for slightly stable conditions can also be generated by mesoscale heterogeneity of the sea surface temperature (SST). Significant measurement errors cannot be ruled out.

The countergradient heat flux for weakly stable conditions is least systematic for weaker winds, even though it occurs with weak winds in all of the datasets. In an effort to reduce offset errors and different SST processing and calibration procedures among field programs, the authors adjusted the SST in each field program to minimize the countergradient flux for weak winds. With or without this adjustment for the combined dataset, the extent of the upward heat flux for weakly stable conditions increases with increasing wind speed.

Corresponding author address: Larry Mahrt, 2171 NW Kari Pl., Corvallis, OR 97330. E-mail: mahrt@nwra.com
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