Nonlinear equatorial Kelvin waves and CISK. II: Finite-amplitude analysis and the leading edge of a cloud region

✍ Scribed by Han-Ru Cho

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 458 KB
• Volume: 126
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49712656310

✦ Synopsis

Abstract

Kelvin wave‐OSK (Conditional Instability of the Second Kind) is studied as a possible explanation for the intraseasonal oscillations of the equatorial troposphere. In this second part of the paper, the finite‐amplitude analysis is performed. It is shown that if one assumes that (he temperature field is separable for the vertical coordinate, then all variables are separable in terms of the vertical coordinate, in the cloud region or in the clear area.

Under the assumption that the temperature is separable, it was found that Kelvin waves with finite amplitude when coupled with cumulus heating are never unstable; this conclusion is the same as for the waves in the small‐amplitude approximation in part I. The rarefaction wave at the leading edge of a cloud region is analysed in detail. The analysis can be done only with the finite‐amplitude approximation because of the requirement of genuine nonlinearity.