Lookup NU author(s): Dr Adrian Constantin,
Emeritus Professor Robin Johnson
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2018, The Author(s). We revisit the classical problem of the behaviour of the wind in the steady atmospheric Ekman layer. We show, for general variable eddy viscosities, that in the Northern Hemisphere the time-averaged ageostrophic wind profile always decays in magnitude and turns clockwise with increasing height. This general result is new; all previous work is based on a few explicit, special examples. As part of the development, we present two ways of formulating the problem, one of which is a novel approach (making use of a transformation to polar coordinates) that helps to explain the complex nature of these flows. The two formulations are supported by several examples that show, for instance, how the deflection angle can be other than the familiar 45 ∘. These results can be used as the basis for testing, and developing, various models for the height variation of eddy viscosity.
Author(s): Constantin A, Johnson RS
Publication type: Article
Publication status: Published
Journal: Boundary-Layer Meteorology
Print publication date: 01/03/2019
Online publication date: 16/11/2018
Acceptance date: 25/10/2018
Date deposited: 05/12/2018
ISSN (print): 0006-8314
ISSN (electronic): 1573-1472
Publisher: Springer Netherlands
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