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Atmospheric Ekman Flows with Variable Eddy Viscosity

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.

Publication metadata

Author(s): Constantin A, Johnson RS

Publication type: Article

Publication status: Published

Journal: Boundary-Layer Meteorology

Year: 2019

Volume: 170

Issue: 3

Pages: 395-414

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


DOI: 10.1007/s10546-018-0404-0


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