Identification

Title

Baroclinic, Alfvén and Rossby waves in geostrophic flow

Abstract

We present here further results concerning geostrophic baroclinic flow with a zonal magnetic field, in a β-plane channel, as extensions of earlier work by the writer. We find a necessary condition for instability that proves the existence of a short wave cutoff of unstable baroclinic waves for finite magnetic field. We also place bounds on the phase velocities of neutral waves in the system. For zero basic baroclinic and a uniform magnetic field, the neutral oscillations are zonally propagating geostrophic Alfvén waves. The lowest mode is purely horizontal and travels at the ordinary Alfvén speed, but all higher modes, which contain vertical as well as horizontal motion, move more slowly. With β ≠ 0, we get, in general, combined Alfvén-Rossby waves, which, in the limit of large rotation, yield a class of waves very similar to those found by Hide. Finally, we solve the Eady problem (stability of baroclinic flow with constant shear) in a uniform magnetic field, without and with the β effect. We find, for β = 0, that the field stabilizes the baroclinic wave. Neutral Alfvén-like waves are found for large field and/or short wavelengths. We also find a pair of "edge waves." For β = 0, the longest baroclinic waves are stabilized for small field strengths, as in the nonmagnetic problem, but very weakly unstable waves occur for larger fields. A set of neutral Rossby waves also is present for long wavelengths and the short Alfvén-like waves are modified, but only slightly.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7s1859r

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

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keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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Temporal reference

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Dataset reference date

date type

publication

effective date

1969-09-01T00:00:00Z

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Conformity

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Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

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