Abstract
Data on the relationship of the surface wind to the geostrophic wind at Porton Down, Salisbury Plain, are presented for various stability conditions and analysed in the light of the Rossbynumber similarity theory. For near-neutral conditions, the geostrophic drag coefficients for geostrophic wind speeds 5 to 15 m s-1 are close to those found by other workers but at higher speeds the values are low. Comparisons of geostrophic and radar wind speeds for ⋍900-m height, suggest that undetectably small mean cyclonic curvatures of the trajectories of the air are responsible for this departure.
A value of the geostrophic drag coefficient for the open sea at wind speeds around 8 m s-1 (neutral conditions) is deduced from recent observations of the drag in relation to the surface wind, combined with the ratios of 900-mb radar wind to surface wind obtained from the North Atlantic weather ship data tabulations of Findlater et al. (1966).
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Anisimova, E. P., Pivovarov, A. A., and Okhanova, N. A.: 1965, ‘Dependence of the Roughness Parameter of the Sea Surface on Wind Velocity’, Izv. Akad. Nauk, S.S.S.R., Atmospheric Ocean Phys. 1, 1101–1102.
Blackadar, A. K.: 1962, ‘The Vertical Distribution of Wind and Turbulent Exchange in a Neutral Atmosphere’, J. Geophys. Res. 67, 3095–3102.
Blackadar, A. K., Panofsky, H. A., Berman, S., Ching, J. K. S., Hess, G. D., and Oliphant, J. E.: 1965, ‘Flux of Heat and Momentum in the Planetary Boundary Layer of the Atmosphere’, Penn. State Univ., Dept. Meteorol., Final Report AFCRL-65-531.
Blackadar, A. K. and Tennekes, H.: 1968, ‘Asymptotic Similarity in Neutral Barotropic Planetary Boundary Layers’, J. Atmospheric Sci. 25, 1015–1020.
Boyden, C. J.: 1963, ‘Relationships Between Sea-Level Isobars and the Wind Speed at 900 m’, Meteorol. Mag. 92, 101–112.
Brocks, K.: 1963, ‘Probleme der maritimen Grenzschicht der Atmosphäre’, Ber. Deuts. Wetterdienstes 91, 34–46.
Brocks, K. and Hasse, L.: 1969, ‘Eine neigungsstabilisierte Boje zur Messung der turbulenten Vertikalflüsse über dem Meer’. Arch. Met. Geophys. Biokl. A18, 331–344.
Businger, J. A.: 1966, ‘Transfer of Momentum and Heat in the Planetary Boundary Layer’, Proc. Symp. Arctic Heat Budget and Atmospheric Circulation, 305–332.
Clarke, R. H.: 1970, ‘Observational Studies in the Atmospheric Boundary Layer’, Quart. J. Roy. Meteorol. Soc. 96, 91–114.
Csanady, G. T.: 1967, ‘On the Resistance Law of a Turbulent Ekman Layer’, J. Atmospheric Sci. 24, 467–471.
Dalrymple, P. C.: 1961, South Pole Micrometeorology Programme. Part I: Data Presentation, Tech. Rep. ES-2, Quartermaster Research Center, Natick, Mass.
Deacon, E. L.: 1953, ‘Vertical Profiles of Mean Wind in the Surface Layers of the Atmosphere’, Geophys. Mem., London 11, No. 91.
Deacon, E. L.: 1962, ‘Aerodynamic Roughness of the Sea’, J. Geophys. Res. 67, 3167–3172.
Dyer, A. J. and Hicks, B. B.: 1970, ‘Flux-Gradient Relationships in the Constant Flux Layer’, Quart. J. Roy. Meteorol. Soc. 96, 715–721.
Fiedler, F. and Panofsly, H. A.: 1972, ‘The Geostrophic Drag Coefficient and the ‘Effective’ Roughness Length’, Quart. J. Roy. Meteorol. Soc. 98, 213–220.
Findlater, J., Harrower, T. N. S., Howkins, C. A., and Wright, H. L.: 1966, ‘Surface and 900 mb Wind Relationships’, Meteorol. Off. London, Sci. Pap. No. 23.
Frankenberger, E. F. H.: 1952, ‘Investigations of the Vertical Exchange Within the Lowest Decameters at Quickborn’, Geophys. Res. Pap. No. 19, G.R.D., Airforce Cambridge Research Center, 323–340.
Frankenberger, E. F. H.: 1955, ‘Über vertikale Temperatur-, Feuchte- und Windgradienten in dem untersten 7 Dekametern der Atmosphäre, den Vertikalaustausch und den Wärmehaushalt an Wiesenboden bei Quickborn/Holstein 1953/54’, Ber. Deuts. Wetterdienstes 3, No. 20.
Gill, A. E.: 1967, The Turbulent Ekman Layer, Dept. Appl. Math. and Theoret. Phys., Univ. of Cambridge, England (unpublished manuscript).
Gill, A. E.: 1968, ‘Similarity Theory and Geostrophic Adjustment’, Quart. J. Roy. Meteorol. Soc. 94, 586–588.
Halstead, M. H., Richman, R. L., Covey, W., and Merryman, J. D.: 1957, ‘A Preliminary Report on the Design of a Computer for Micrometeorology’, J. Meteorol. 14, 308–325.
Hasse, L. and Wagner, V.: 1971, ‘On the Relationship Between Geostrophic and Surface Wind at Sea’, Mon. Weather Rev. 99, 255–260.
Hicks, B. B. and Dyer, A. J.: 1970, ‘Measurements of Eddy-Fluxes Over the Sea from an Off-shore Oil Rig’, Quart. J. Roy. Meteorol. Soc. 96, 523–528.
Hoeber, H.: 1969, ‘Wind-, Temperatur- und Feuchteprofile in der Wassernahen Luftschicht über dem äquatorialen Atlantik’, ‘Meteor’ Forschungsergebnisse, B, No. 3, 1–26.
Johnson, N. K.: 1929, ‘A Study of the Vertical Gradient of Temperature in the Atmosphere Near the Ground’, Geophys. Mem., London 5, 32 pp.
Johnson, W. B.: 1962, ‘Climatology of Atmospheric Boundary-Layer Parameters’, in Final Report, ‘Studies of the Three-Dimensional Structure of the Planetary Boundary Layer’, Dept. of Meteorology, Univ. of Wisconsin.
Johnson, W. B.: 1965, ‘Atmospheric Boundary-Layer Dynamics Over the Forests of Northeastern Wisconsin’, Ph. D. Thesis, Dept. of Meteorol., Univ. of Wisconsin.
Kazansky, A. B. and Monin, A. S.: 1961, ‘The Dynamic Interaction Between the Atmosphere and the Land Surface’, Izv. Akad. Nauk., S.S.S.R., Geophys. Ser. No. 5, 786–788.
Lettau, H. H.: 1950, ‘A Re-examination of the Leipzig Wind Profile’, Tellus 2, 125–129.
Lettau, H. H.: 1959, ‘Wind Profile, Surface Stress and Geostrophic Drag Coefficient in the Atmospheric Surface Layer’, Advances in Geophys. 6, 241–157.
Lettau, H. H.: 1962, ‘Theoretical Wind Spirals in the Boundary Layer of a Barotropic Atmosphere’, Beitr. Phys. Atmos. 35, 195–212.
Lettau, H. H. and Davidson, B.: 1957, Exploring the Atmosphere's First Mile, Pergamon Press, New York, N.Y., 578 pp.
McVehil, G. E.: 1964, ‘Wind and Temperature Profiles Near the Ground in Stable Stratification’, Quart. J. Roy. Meteorol. Soc. 90, 136–146.
Panofsky, H. A. and Townsend, A. A.: 1964, ‘Change of Terrain Roughness and the Wind Profile’, Quart. J. Roy. Meteorol. Soc. 90, 147–155.
Paulson, C. A.: 1967, ‘Profiles of Wind Speed, Temperature and Humidity Over the Sea’, Univ. Wash., Dept. Atmos. Sci., Sci. Rept. GP-2418, 116 pp.
Pond, S., Phelp, 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. Atmos. Sci. 28, 901–907.
Roll, H. U., 1965, Physics of the Marine Atmosphere, Academic Press, New York, N.Y., 426 pp.
Smith, S. D.: 1970, ‘Thrust-Anemometer Measurements of Wind Turbulence, Reynolds Stress, and Drag Coefficient Over the Sea’, J. Geophys. Res. 75, 6578–6770.
Townsend, A. A.: 1966, ‘The Flow in a Turbulent Boundary Layer After a Change in Surface Roughness’, J. Fluid Mech. 26, 255–266.
Warner, J.: 1972, ‘The Structure and Intensity of Turbulence Over the Sea’, Quart. J. Roy. Meteorol. Soc. 98, 175–186.
Webb, E. K.: 1970, ‘Profile Relationships: The Log-Linear Range and Extension to Strong Stability’, Quart. J. Roy. Meteorol. Soc. 96, 67–90.
Zilitinkevich, S. S., Laikhtman, D. L., and Monin, A. S.: 1967, ‘Dynamics of the Atmospheric Boundary Layer’, Izv. Akad. Nauk., S.S.S.R., Atmospheric Ocean. Phys. 3, (3); 170–191.
Zilitinkevich, S. S. and Chalikov, D. V.: 1968, ‘The Laws of Resistance and of Heat and Moisture Exchange in the Interaction Between the Atmosphere and the Underlying Surface’, Izv. Akad. Nauk., S.S.S.R., Atmos. and Ocean Phys. 4, (7), 765–772.
Zubkovskii, S. L. and Kravchenko, T. K.: 1967, ‘Direct Measurement of Some Characteristics of Atmospheric Turbulence in the Near-Water Layer’, Izv. Akad. Nauk., S.S.S.R., Atmospheric Ocean. Phys. 3, 127–135.
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Deacon, E.L. Geostrophic drag coefficients. Boundary-Layer Meteorol 5, 321–340 (1973). https://doi.org/10.1007/BF00155240
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DOI: https://doi.org/10.1007/BF00155240