Poincare wave

From Glossary of Meteorology



Poincare wave

A gravity wave that is slow enough (low frequency) to feel the effects of the earth's rotation, so that the Coriolis parameter appears in the dispersion relation.

Within a channel in a rotating system, a Poincare wave has sinusoidally varying cross-channel velocity with an integral or half integral number of cross-channel waves spanning the channel. In the shallow water approximation the waves have dispersion relationship with squared frequency
ams2001glos-Pe19
in which f is the Coriolis parameter, k is the wavenumber along the channel, L is the width of the channel, n is any positive integer, and c is the phase speed for shallow water gravity waves;
ams2001glos-Pe20
in which g is the acceleration due to gravity and H is the mean depth of the fluid. Related to Poincare waves are Kelvin waves, which take the role of the mode with n = 0.


Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. 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.