Abstract
The stationary, Ekman-layer equations have been solved in closed form for two expressions of the eddy viscosity as a function of height, z: v τ=cu*z(1−z/h)and v τ=cu*z(1−z/h) 2, where u* is the friction velocity, h the boundary-layer height and c a constant. The main difference between both solutions is that the quadratic K-profile leads to a velocity discontinuity at the top of the boundary layer, while the solution for the cubic profile approaches the geostrophic wind at z=h smoothly. We discuss the characteristics of the solutions in terms of a dimensionless parameter C=fh/cu*, where f is the Coriolis parameter. The dependence on C can be interpreted in terms of a varying boundary-layer height or in terms of stability. The results for C ~ 1 are related to a neutral boundary layer. They agree well with results of a second-order model. The limit C → 0 is investigated in detail. We find that the stress profile becomes linear. The velocity profile shows different characteristics depending on whether we consider a shallow or a very unstable boundary layer. The results agree with observations. Finally we consider the influence of baroclinicity on the wind and stress profiles.
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References
Abramowitz, M. and Stegun, I. A.: 1965, Handbook of Mathematical Functions, Dover, New York.
Arya, S. P. S. and Wyngaard, J. C.: 1975, ‘Effect of Baroclinicity on Wind Profiles and the Geostrophic Drag Law for the Convective Planetary Boundary Layer’, J. Atmos. Sci. 32, 767–778.
Brost, R. A., Lenschow, D. H., and Wyngaard, J. C.: 1982a, ‘Marine Stratocumulus Layers. Part I: Mean Conditions’, J. Atmos. Sci. 39, 800–817.
Brost, R. A., Wyngaard, J. C., and Lenschow, D. H.: 1982b, ‘Marine Stratocumulus Layers. Part II: Turbulence Budgets’, J. Atmos. Sci. 39, 818–835.
Brown, R. A.: 1974, Analytical Methods in Planetary Boundary Layer Modelling, Adam Hilger, London.
Businger, J. A.: 1982, in F. T. M. Nieuwstadt and H. van Dop (eds.), ‘Equations and Concepts’, Atmospheric Turbulence and Air Pollution Modelling, D. Reidel Publ. Co., Dordrecht, Holland, pp. 1–36.
Csanady, G. T.: 1974, ‘Equilibrium Theory of the Planetary Boundary Layer with an Inversion Lid’, Boundary-Layer Meteorol. 6, 63–79.
Deardorff, J. W. and Mahrt, L.: 1982, ‘On the Dichotomy of Theoretical Treatments of the Atmospheric Boundary Layer’, J. Atmos. Sci. 39, 2096–2098.
Kaimal, J. C., Wyngaard, J. C., Haugen, D. A., Coté, O. R., Izumi, Y., Caughey, S. J., and Readings, C. J.: 1976, ‘Turbulence Structure in the Convective Boundary Layer’, J. Atmos. Sci. 33, 2152–2169.
Krishna, K.: 1980, ‘The Planetary Boundary Layer Model of Ellison (1956) - Retrospect’, Boundary-Layer Meteorol. 19, 293–301.
Lenschow, D. H., Wyngaard, J. C., and Pennell, W. T.: 1980, ‘Mean Field and Second-Moment Budgets in a Baroclinic Convective Boundary Layer’, J. Atmos. Sci. 37, 1313–1326.
Swinbank, W. C.: 1980, ‘Structure of Wind and the Shearing Stress in the Planetary Boundary Layer’, Arch. Met. Geophys. Biokl. Ser. A 19, 1–12.
Tennekes, H.: 1982, ‘Similarity Relations, Scaling Laws and Spectral Dynamics’, in F. T. M. Nieuwstadt and H. van Dop (eds.), Atmospheric Turbulence and Air Pollution Modelling, D. Reidel Publ. Co., Dordrecht, Holland, pp. 37–68.
Wippermann, F.: 1973, The Planetary Boundary Layer of the Atmosphere, Deutsche Wetterdienst.
Wyngaard, J. C.: 1982, ‘Boundary-Layer Modelling’, in F. T. M. Nieuwstadt and H. van Dop (eds.), Atmospheric Turbulence and Air Pollution Modelling, D. Reidel Publ. Co., Dordrecht, Holland, pp. 69–106.
Wyngaard, J. C., Coté, O. R., and Rao, K. S.: 1974, ‘Modeling the Atmospheric Boundary Layer’, Adv. Geophys. 18A, Academic Press, New York.
Yokoyama, O., Gamo, M., and Yamamoto, S.: 1977, ‘On the Turbulence Quantities in the Neutral Atmospheric Boundary Layer’, J. Meteorol. Soc. Japan 55, 312–318.
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Nieuwstadt, F.T.M. On the solution of the stationary, baroclinic Ekman-layer equations with a finite boundary-layer height. Boundary-Layer Meteorol 26, 377–390 (1983). https://doi.org/10.1007/BF00119534
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DOI: https://doi.org/10.1007/BF00119534