Baroclinic instability governed by the modified quasi-geostrophic equations

✍ Scribed by A. A. White; A. M. Gadian

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 521 KB
• Volume: 105
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710544602

✦ Synopsis

Abstract

Results are presented for the baroclinic instability of zonal flows on a β‐plane according to the modified quasi‐geostrophic equations (which retain a non‐Doppler term in the rigid horizontal boundary condition).Numerical techniques, with up to 180 interior levels, are used. In the absence of a β‐effect the instability of the longer waves is fairly sensitive to the non‐Doppler term, the more so if static compressibility is neglected. A realistic β‐effect markedly reduces this sensitivity: the weakly unstable long waves are essentially internal mode phenomena and are consequently little affected by the non‐Doppler term. It is confirmed that the stable external mode Rossby waves, where they exist, are radically altered when the term is included..