Interpretation of ageostrophic winds and implications for jet stream maintenance

Blackburn, M. (1985) Interpretation of ageostrophic winds and implications for jet stream maintenance. Journal of the Atmospheric Sciences, 42 (23). pp. 2604-2620. ISSN 1520-0469 doi: 10.1175/1520-0469(1985)042<2604:IOAWAI>2.0.CO;2

Abstract/Summary

The use of ageostrophic flow to infer the presence of vertical circulations in the entrances and exits of the climatological jet streams is questioned. Problems of interpretation arise because of the use of different definitions of geostrophy in theoretical studies and in analyses of atmospheric data. The nature and role of the ageostrophic flow based on constant and variable Coriolis parameter definitions of geostrophy vary. In the latter the geostrophic divergence cannot be neglected, so the vertical motion is not associated solely with the ageostrophic flow. Evidence is presented suggesting that ageostrophic flow in the climatological jet streams is primarily determined by the kinematic requirements of wave retrogression rather than by a forcing process. These requirements are largely met by the rotational flow, with the divergent circulations present being geostrophically forced, and so playing a secondary, restoring role.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/34992
Identification Number/DOI	10.1175/1520-0469(1985)042<2604:IOAWAI>2.0.CO;2
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Meteorological Society
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