Depth of frictional influence

From Glossary of Meteorology

depth of frictional influence

The depth below the ocean surface to which the stress (horizontal force/unit area) of the wind reaches.

To measure this depth, the turbulent stress must be directly measured. This is rarely done, but is more often inferred through observations of current profiles and fitting to an Ekman layer profile [e.g., Eqs. (9.9) and (9.10) in Pond and Pickard (1978)]. Because of the strong effect stratification has on turbulent transport, the depth of frictional influence is also taken to be equal to the depth of the mixed layer, and this is in turn found by observations of temperature and/or salinity profiles.

Pond, S., and G. L. Pickard 1978. Introductory Dynamic Oceanography. Pergamon Press, . p. 87.

Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.