• Anderson, R. J., , and S. D. Smith, 1981: Evaporation coefficients for the sea surface from eddy flux measurements. J. Geophys. Res., 86 , 449456.

    • Search Google Scholar
    • Export Citation
  • Beljaars, A. C. M., 1994: The impact of some aspects of the boundary layer scheme in the ECMWF model. Proc. Seminar on Parameterization of Sub-grid Scale Processes, Reading, United Kingdom, ECMWF, 125–161.

    • Search Google Scholar
    • Export Citation
  • Beljaars, A. C. M., , and P. Viterbo, 1998: The role of the boundary layer in a numerical weather prediction model. Clear and Cloudy Boundary Layers, A. A. M. Holtslag and P. G. Duynkerke, Eds., Royal Netherlands Academy of Arts and Sciences, 287–304.

    • Search Google Scholar
    • Export Citation
  • Bony, S., , Y. Sud, , K. M. Lau, , J. Susskind, , and S. Saha, 1997: Comparison and satellite assessment of NASA/DAO and NCEP–NCAR reanalyses over tropical ocean: Atmospheric hydrology and radiation. J. Climate, 10 , 14411462.

    • Search Google Scholar
    • Export Citation
  • Brutsaert, W. H., 1975: A theory for local evaporation (or heat transfer) from rough and smooth surfaces at ground level. Water Resour. Res., 11 , 543550.

    • Search Google Scholar
    • Export Citation
  • Brutsaert, W. H., . 1982: Evaporation into the Atmosphere—Theory, History and Applications. Reidel, 299 pp.

  • Bumke, K., , K. Uhlig, , H. Berdt, , and M. Clemens, 2001: Measurements of snow fall over the Labrador Sea. J. Phys. Oceanogr., submitted.

  • Bumke, K., , U. Karger, , and K. Uhlig, . 2002: Measurements of turbulent fluxes of momentum and sensible heat over the Labrador Sea. J. Phys. Oceanogr., 32 , 401410.

    • Search Google Scholar
    • Export Citation
  • Businger, J. A., , J. C. Wyngaard, , Y. Izumi, , and E. F. Bradley, 1971: Flux-profile relationships in the atmospheric surface layer. J. Atmos. Sci., 28 , 181189.

    • Search Google Scholar
    • Export Citation
  • Charnock, H., 1955: Wind stress on a water surface. Quart. J. Roy. Meteor. Soc., 81 , 639640.

  • DeCosmo, J., , K. B. Katsaros, , S. D. Smith, , R. J. Anderson, , W. A. Oost, , K. Bumke, , and H. Chadwick, 1996: Air–sea exchange of water vapor and sensible heat: The Humidity Exchange over the Sea (HEXOS) results. J. Geophys. Res., 101 , 1200112016.

    • Search Google Scholar
    • Export Citation
  • Dickson, R., , J. Lazier, , J. Meinke, , P. Rhines, , and J. Swift, 1996: Long-term coordinated changes in convective activity of the North Atlantic. Progress in Oceanography, Vol. 38, Pergamon, 241–295.

    • Search Google Scholar
    • Export Citation
  • Dyer, A. J., 1974: A review of flux-profile relationships. Bound.-Layer Meteor., 7 , 363372.

  • ECMWF, 1995: User guide to ECMWF products 2.1. Meteor. Bull. M3-2, 71 pp.

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

    • Search Google Scholar
    • Export Citation
  • Garratt, J. R., 1992: The Atmospheric Boundary Layer. Cambridge University Press, 316 pp.

  • Grachev, A. A., , C. W. Fairall, , and S. E. Larsen, 1998: On the determination of the neutral drag coefficient in the convective boundary layer. Bound.-Layer Meteor., 86 , 257278.

    • Search Google Scholar
    • Export Citation
  • Holtslag, A. A. M., , E. I. F. de Bruijn, , and H-L. Pan, 1990: A high resolution air mass transformation model for short-range weather forecasting. Mon. Wea. Rev., 118 , 15611575.

    • Search Google Scholar
    • Export Citation
  • Isemer, H. J., , and L. Hasse, 1989: The BUNKER Climate Atlas of the North Atlantic Ocean,. Vol. 2: Air–Sea Interactions, Springer-Verlag, 256 pp.

    • Search Google Scholar
    • Export Citation
  • Josey, S. A., 2001: A comparison of ECMWF, NCEP–NCAR, and SOC surface heat fluxes with moored buoy measurements in the subduction region of the northeast Atlantic. J. Climate, 14 , 17801789.

    • Search Google Scholar
    • Export Citation
  • Josey, S. A., , E. C. Kent, , and P. K. Taylor, . 1999: New insights into the ocean heat budget closure problem from analysis of the SOC air–sea flux climatology. J. Climate, 12 , 28562880.

    • Search Google Scholar
    • Export Citation
  • Kader, B. A., , and A. M. Yaglom, 1990: Mean fields and fluctuation moments in unstably stratified turbulent boundary layers. J. Fluid Mech., 212 , 637662.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors. 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Kanimitsu, M., , W. Ebisuzaki, , J. Woolen, , J. Potter, , and M. Fiorino, 1999: An overview of NCEP/DOE reanalysis-2. Proc. Second Int. Conf. on Reanalysis, Reading, United Kingdom, ECMWF, 18.

    • Search Google Scholar
    • Export Citation
  • Killworth, P. D., 1983: Deep convection in the world ocean. Rev. Geophys. Space Phys., 21 , 126.

  • Komen, G., , P. A. E. M. Janssen, , V. Makin, , and W. Oost, 1998: On the sea state dependence of the Charnock parameter. Global Atmos. Ocean Syst., 5 , 367388.

    • Search Google Scholar
    • Export Citation
  • Lab Sea Group, 1998: The Labrador Sea Deep Convection Experiment. Bull. Amer. Meteor. Soc., 79 , 20332058.

  • Liu, W. T., , K. B. Katsaros, , and J. A. Businger, 1979: Bulk parameterization of air–sea exchanges of heat and water vapor including the molecular constraints at the interface. J. Atmos. Sci., 36 , 17221735.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., , and F. Schott, 1999: Open-ocean convection: Observations, theory and models. Rev. Geophys., 37 , 164.

  • Moat, B., , and M. Yelland, 1998: Airflow distortion at instrument sites on the R/V Knorr. Southampton Oceanography Centre, 29 pp.

  • Pagowski, M., , and G. W. K. Moore, 2001: A numerical study of an extreme cold-air outbreak over the Labrador Sea: Sea-ice air–sea interaction and the development of polar lows. Mon. Wea. Rev., 129 , 4772.

    • Search Google Scholar
    • Export Citation
  • Paulson, C. A., 1970: The mathematical representation of wind speed and temperature profiles in the unstable atmospheric surface layer. J. Appl. Meteor., 9 , 857861.

    • Search Google Scholar
    • Export Citation
  • Renfrew, I. A., , and G. W. K. Moore, 1999: An extreme cold air outbreak over the Labrador Sea: Roll vortices and air–sea interaction. Mon. Wea. Rev., 127 , 23792394.

    • Search Google Scholar
    • Export Citation
  • Renfrew, I. A., , G. W. K. Moore, , T. R. Holt, , S. W. Chang, , and P. Guest, . 1999: Mesoscale forecasting during a field program: Meteorological support of the Labrador Sea Deep Convection Experiment. Bull. Amer. Meteor. Soc., 80 , 605620.

    • Search Google Scholar
    • Export Citation
  • Reynolds, R. W., , and T. M. Smith, 1994: Improved global sea surface temperature analyses using optimum interpolation. J. Climate, 7 , 929948.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., , J. Gilson, , B. Cornuelle, , and R. Weller, 2001: Mean and time-varying meridional transport of heat at the tropical/subtropical boundary of the North Pacific Ocean. J. Geophys. Res., 106 , 89578970.

    • Search Google Scholar
    • Export Citation
  • Shinoda, T., , H. Hendon, , and J. Glick, 1999: Intraseasonal surface fluxes in the tropical western Pacific and Indian Oceans from NCEP reanalyses. Mon. Wea. Rev., 127 , 678693.

    • Search Google Scholar
    • Export Citation
  • Smith, S. D., 1980: Wind stress and heat flux over the ocean in gale force winds. J. Phys. Oceanogr., 10 , 709726.

  • Smith, S. D., . 1988: Coefficients for sea surface wind stress, heat flux, and wind profiles as a function of wind speed and temperature. J. Geophys. Res., 93 , 1546715472.

    • Search Google Scholar
    • Export Citation
  • Smith, S. R., , D. M. Legler, , and K. V. Verzone, 1999: Quantifying uncertainties in NCEP reanalyses using high-quality research vessel observations. Proc. Second Conf. on Reanalyses, Reading, United Kingdom, ECMWF, 87.

    • Search Google Scholar
    • Export Citation
  • Sverdrup, H. U., , M. W. Johnson, , and R. H. Fleming, 1942: The Oceans: Their Physics, Chemistry and General Biology. Prentice Hall, 1087 pp.

    • Search Google Scholar
    • Export Citation
  • Taylor, P. K., , and M. J. Yelland, 2001: The dependence of sea surface roughness on the height and steepness of the waves. J. Phys. Oceanogr., 31 , 572590.

    • Search Google Scholar
    • Export Citation
  • Weller, R. A., , M. F. Baumgartner, , S. A. Josey, , A. S. Fischer, , and J. C. Kindle, 1998: Atmospheric forcing in the Arabian Sea during 1994–1995: Observations and comparisons with climatology and models. Deep-Sea Res., 45 , 19611999.

    • Search Google Scholar
    • Export Citation
  • Wood, R. A., , A. B. Keen, , J. F. B. Mitchell, , and J. M. Gregory, 1999: Changing spatial structure of the thermohaline circulation in response to atmospheric CO2 forcing in a climate model. Nature, 399 , 572575.

    • Search Google Scholar
    • Export Citation
  • Zeng, X., , M. Zhao, , and R. E. Dickinson, 1998: Intercomparison of bulk aerodynamical 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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A Comparison of Surface Layer and Surface Turbulent Flux Observations over the Labrador Sea with ECMWF Analyses and NCEP Reanalyses

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  • 1 British Antarctic Survey, Cambridge, United Kingdom
  • | 2 Department of Physics, University of Toronto, Toronto, Ontario, Canada
  • | 3 Naval Postgraduate School, Monterey, California
  • | 4 Institut für Meereskunde, Universität Kiel, Kiel, Germany
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Abstract

Comparisons are made between a time series of meteorological surface layer observational data taken on board the R/V Knorr, and model analysis data from the European Centre for Medium-Range Weather Forecasting (ECMWF) and the National Centers for Environmental Prediction (NCEP). The observational data were gathered during a winter cruise of the R/V Knorr, from 6 February to 13 March 1997, as part of the Labrador Sea Deep Convection Experiment. The surface layer observations generally compare well with both model representations of the wintertime atmosphere. The biases that exist are mainly related to discrepancies in the sea surface temperature or the relative humidity of the analyses.

The surface layer observations are used to generate bulk estimates of the surface momentum flux, and the surface sensible and latent heat fluxes. These are then compared with the model-generated turbulent surface fluxes. The ECMWF surface sensible and latent heat flux time series compare reasonably well, with overestimates of only 13% and 10%, respectively. In contrast, the NCEP model overestimates the bulk fluxes by 51% and 27%, respectively. The differences between the bulk estimates and those of the two models are due to different surface heat flux algorithms. It is shown that the roughness length formula used in the NCEP reanalysis project is inappropriate for moderate to high wind speeds. Its failings are acute for situations of large air–sea temperature difference and high wind speed, that is, for areas of high sensible heat fluxes such as the Labrador Sea, the Norwegian Sea, the Gulf Stream, and the Kuroshio. The new operational NCEP bulk algorithm is found to be more appropriate for such areas.

It is concluded that surface turbulent flux fields from the ECMWF are within the bounds of observational uncertainty and therefore suitable for driving ocean models. This is in contrast to the surface flux fields from the NCEP reanalysis project, where the application of a more suitable algorithm to the model surface-layer meteorological data is recommended.

Corresponding author address: Ian Renfrew, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom. Email: i.renfrew@bas.ac.uk

Abstract

Comparisons are made between a time series of meteorological surface layer observational data taken on board the R/V Knorr, and model analysis data from the European Centre for Medium-Range Weather Forecasting (ECMWF) and the National Centers for Environmental Prediction (NCEP). The observational data were gathered during a winter cruise of the R/V Knorr, from 6 February to 13 March 1997, as part of the Labrador Sea Deep Convection Experiment. The surface layer observations generally compare well with both model representations of the wintertime atmosphere. The biases that exist are mainly related to discrepancies in the sea surface temperature or the relative humidity of the analyses.

The surface layer observations are used to generate bulk estimates of the surface momentum flux, and the surface sensible and latent heat fluxes. These are then compared with the model-generated turbulent surface fluxes. The ECMWF surface sensible and latent heat flux time series compare reasonably well, with overestimates of only 13% and 10%, respectively. In contrast, the NCEP model overestimates the bulk fluxes by 51% and 27%, respectively. The differences between the bulk estimates and those of the two models are due to different surface heat flux algorithms. It is shown that the roughness length formula used in the NCEP reanalysis project is inappropriate for moderate to high wind speeds. Its failings are acute for situations of large air–sea temperature difference and high wind speed, that is, for areas of high sensible heat fluxes such as the Labrador Sea, the Norwegian Sea, the Gulf Stream, and the Kuroshio. The new operational NCEP bulk algorithm is found to be more appropriate for such areas.

It is concluded that surface turbulent flux fields from the ECMWF are within the bounds of observational uncertainty and therefore suitable for driving ocean models. This is in contrast to the surface flux fields from the NCEP reanalysis project, where the application of a more suitable algorithm to the model surface-layer meteorological data is recommended.

Corresponding author address: Ian Renfrew, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom. Email: i.renfrew@bas.ac.uk

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