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Instability in a geostrophic wind with a transverse wind‐speed gradient
Author(s) -
Wilson S. D. R.
Publication year - 1965
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49709138803
Subject(s) - geostrophic wind , transverse plane , disturbance (geology) , inviscid flow , instability , mechanics , wind speed , wind gradient , physics , meteorology , geology , wind direction , engineering , paleontology , structural engineering
The stability of an airstream in geostrophic balance, with a transverse velocity gradient, to horizontal displacements of a single particle has previously been investigated. Here, the effect on such an airstream of a general three‐dimensional disturbance, taking account of the stable density gradient of the air, is considered. A necessary and sufficient condition for instability is obtained for an inviscid airstream and a two‐dimensional disturbance (independent of the downstream coordinate). Finally we discuss how this criterion is modified if viscosity is introduced, and also if the disturbance is allowed to be three‐dimensional.