Abstract
The structure of atmospheric turbulence in the surface layer over the open ocean is examined under conditions of local free convection. The raw data consist of profile and fluctuation measurements of wind and temperature as obtained from a meteorological buoy. For near neutral conditions and for waves running approximately along the wind direction, wave-induced wind fluctuations can be described by a simplified linear theory based on Miles (1957). In this case, the spectrum of wind velocity is given as the sum of two parts; for the turbulent part, the parameterization as obtained by Kaimal et al. (1972) applies, while the wave-induced part is parameterized using a simplification of Miles' linear theory. For cases of local free convection, the measurements of the vertical component of the wind velocity are well described by similarity theory; as expected, Σ w /(-u′w∼)1/2 is proportional to (- z/L)1/3. In order to scale the longitudinal wind velocity component, it seems to be reasonable to extend the list of relevant parameters by the height of the mixed layer z i. We obtain Σ u /(- u′w∼)1/2 ∫ (z/z i)1/3(- z/L)1/3 with only a poor correlation coefficient of r = 0.6. Overall, the results of local free convection scaling obtained from direct measurements show good agreement with those obtained from profile measurements. A comparison between direct and indirect determination of turbulent fluxes of momentum shows an unexplained difference of about 20%. This discrepancy is mainly due to a gap in the u′w∼-cospectrum at the swell frequency.
Similar content being viewed by others
References
Benjamin, T. B.: 1959, ‘Shearing Flow over a Wavy Boundary’, J. Fluid Mech. 6, 161–205.
Berkowicz, R. and Prahm, L. P.: 1981, ‘Note on Turbulent Scaling Parameters for the Convective Planetary Boundary Layer’, Boundary-Layer Meteorol. 21, 215–222.
Brümmer, B.: 1979, ‘Boundary-Layer Processes during the Life Cycle of GATE Convective Disturbances’, Contrib. Atm. Phys. 52, 306–330.
Businger, J. A.: 1973, ‘A Note on Free Convection’, Boundary-Layer Meteorol. 4, 323–326.
Cardone, V., Carlson, H., Ewing, J. A., Hasselmann, K., Lazanoff, S., Ross, D., and McLeish, W.: 1981, ‘The Surface Wave Environment in the GATE B/C Scale — Phase III’, J. Phys. Ocean. 11, 1280–1293.
Champagne, F. H., Friehe, C. A., LaRue, J. C., and Wyngaard, J. C.: 1977, ‘Flux Measurements, Flux Estimation Techniques, and Fine-Scale Turbulence Measurements in the Unstable Surface Layer over Land’, J. Atm. Sci. 34, 515–530.
Chao, S. P. and Hsu, E. Y.: 1978, ‘Wave-Induced Velocities and Turbulent Reynolds Stresses above an Air-Water Interface’, Dynam. of Atm. and Oceans 2, 471–493.
Coulman, C. E.: 1980, ‘Correlations between Velocity, Temperature and Humidity Fluctuations in the Air above Land and Ocean’, Boundary-Layer Meteorol. 19, 403–420.
Crow, E. L., Davis, F. A., and Maxfield, M. W.: 1960, ‘Statistics Manual’, Dover Publications, New York, 288 pp.
Dyer, A. J.: 1967, ‘The Turbulent Transport of Heat and Water Vapour in an Unstable Atmosphere’, Quart. J. Roy. Meteorol. Soc. 93, 501–508.
Elliott, J. A.: 1972, ‘Microscale Pressure Fluctuations near Waves Being Generated by the Wind’, J. Fluid Mech. 54, 427–448.
Greenhut, G. K.: 1981, ‘Analysis of Aircraft Measurements of Momentum Flux in the Subcloud Layer over the Tropical Atlantic Ocean during GATE’, Boundary-Layer Meteorol. 20, 75–100.
Hasse, L., Grünewald, M., Wucknitz, J., Dunckel, M., and Schriever, D.: 1978: ‘Profile Derived Turbulent Fluxes in the Surface Layer under Disturbed and Undisturbed Conditions during GATE’, Meteor. Forsch. Ergebnisse, Reihe B, 13, 24–40.
Hasselmann, D. E., Dunckel, M., and Ewing, J. A.: 1980, ‘Directional Wave Spectra Observed during JONSWAP 1973’, J. Phys. Oceanogr. 10, 1264–1280.
Kaimal, J. C.: 1978, ‘Horizontal Velocity Spectra in an Unstable Surface Layer’, J. Atm. Sci. 35, 18–24.
Kaimal, J. C., Wyngaard, J. C., Izumi, Y., and Coté, O. R.: 1972, ‘Spectral Characteristics of Surface Layer Turbulence’, Quart. J. Roy. Meteorol. Soc. 98, 563–589.
Kondo, J., Fujinawa, Y., and Naito, G.: 1972, ‘Wave-Induced Wind Fluctuations over the Sea’, J. Fluid Mech. 51, 751–771.
Kruspe, G.: 1974, ‘Measurements of Fluctuations of Vertical Wind Velocity, Temperature, and Radio-Refractive Index above the Sea’, Boundary-Layer Meteorol. 6,257–267.
Large, W. G. Pond, S.: 1982, ‘Sensible and Latent Heat Flux Measurements over the Ocean’, J. Phys. Ocean. 12, 464–482.
Lenschow, D. H. and Stephens, P. L.: 1980, ‘The Role of Themals in the Convective Boundary Layer’, Boundary-Layer Meteorol. 19, 509–532.
Lumley, J. L. and Panofsky, H. A.: 1964, ‘The Structure of Atmospheric Turbulence’, Interscience Publishers, New York, 239 pp.
Manton, M. J.: 1977, ‘On the Structure of Convection’, Boundary-Layer Meteorol. 12, 491–503.
McBean, G. A.: 1971, ‘The Variations of the Statistics of Wind, Temperature and Humidity Fluctuations with Stability’, Boundary-Layer Meteorol. 1, 438–457.
Miles, J. W.: 1957, ‘On the Generation of Surface Waves by Shear Flows’, J. Fluid Mech. 3, 185–204.
Mizuno, T.: 1982, ‘On the Similarity of the Characteristics of Turbulence in an Unstable Boundary Layer’, Boundary-Layer Meteorol. 23, 69–83.
Panofsky, H. A.: 1963, ‘Determination of Stress from Wind and Temperature Measurements’, Quart. J. Roy. Meteorol. Soc. 83, 85–94.
Panofsky, H. A., Tennekes, H., Lenschow, D. H., and Wyngaard, J. C.: 1977, ‘The Characteristics of Turbulent Velocity Components in the Surface Layer under Convective Conditions’, Boundary-Layer Meteorol. 11, 355–361.
Phelps, G. T. and Pond, S.: 1971, ‘Spectra of the Temperature and Humidity Fluctuations and of the Fluxes of Moisture and Sensible Heat in the Marine Boundary Layer’, J. Atm. Sci. 28, 918–928.
Pond, S., Phelps, G. T., Paquin, J. E., McBean, G., and Stewart, R. W.: 1971, ‘Measurements of the Turbulent Fluxes of Momentum, Moisture and Sensible Heat over the Ocean’, J. Atm. Sci. 28, 901–917.
Schmitt, K. F., Friehe, C. A., and Gibson, C. H.: 1978, ‘Humidity Sensitivity of Atmospheric Temperature Sensors by Salt Contamination’, J. Phys. Ocean. 8, 151–161.
Smith, S. D.: 1980, ‘Wind Stress and Heat Flux over the Ocean in Gale Force Winds’, J. Phys. Ocean 10, 709–726.
Snyder, R. L.: 1974, ‘A Field Study of Wave-Induced Pressure Fluctuations above Surface Gravity Waves’, J. Marine Res. 32, 497–531.
Tennekes, H.: 1982, ‘Similarity Relations, Scaling Laws and Spectral Dynamics’, in Atmospheric Turbulence and Air Pollution Modelling, D. Reidel Publ. Co., Holland, pp. 37–68.
Volkov, Yu. A.: 1969, ‘The Spectra of Velocity and Temperature Fluctuations in Airflow above the Agitated Sea Surface’, Izv., Atmos. and Ocean. Phys. 5, 1251–1265.
Wolf, H.: 1968, Ausgleichsrechnung nach der Methode der kleinsten Quadrate, Ferd. Dümmlers Verlag, Bonn, pp. 417–422.
Wucknitz, J.: 1976, ‘Determination of Turbulent Fluxes of Momentum and Sensible Heat from Fluctuation Measurements and the Structure of Wind Field over Waves above the Tropical Atlantic during ATEX’, Meteor-Forschungsergebnisse B11, 25–50.
Wyngaard, J. C. and Coté, O. R.: 1972, ‘Cospectral Similarity in the Atmospheric Surface Layer’, Quart. J. Roy. Meteorol. Soc. 98, 590–603.
Wyngaard, J. C.: 1973, ‘On Surface Layer Turbulence’, in Workshop on Micrometeorology, AMS, Boston, 101–149.
Wyngaard, J. C., Coté, O. R., and Izumi, Y.: 1971, ‘Local Free Convection, Similarity and the Budgets of Shear Stress and Heat Flux’, J. Atm. Sci. 28, 1171–1182.
Zank, I.: 1981, ‘Sources of Errors and Running Calibration of Three-dimensional Hot-film Anemometers especially near the Sea-Surface’, DISA Information 26, 11–18.
Zank, S.: 1983, ‘Skalierungseigenschaften der wassernahen Luftschicht über dem offenen Ozean bei labilen und konvektiven Bedingungen’, Geophys. Einzelschriften, No. 64.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Zank, S. Free convection scaling over the ocean derived from buoy measurements during gate. Boundary-Layer Meteorol 29, 139–153 (1984). https://doi.org/10.1007/BF00206827
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00206827