Journal article

The counter-propagating rossby-wave perspective on baroclinic instability. Part IV: Nonlinear life cycles

J Methven, BJ Hoskins, E Heifetz, CH Bishop

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY | ROYAL METEOROLOGICAL SOC | Published : 2005

Abstract

Pairs of counter-propagating Rossby waves (CRWs) can be used to describe baroclinic instability in linearized primitive-equation dynamics, employing simple propagation and interaction mechanisms at only two locations in the meridional plane - the CRW 'home-bases'. Here, it is shown how some CRW properties are remarkably robust as a growing baroclinic wave develops nonlinearly. For example, the phase difference between upper-level and lower-level waves in potential-vorticity contours, defined initially at the home-bases of the CRWs, remains almost constant throughout baroclinic wave life cycles, despite the occurrence of frontogenesis and Rossby-wave breaking. As the lower wave saturates nonl..

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University of Melbourne Researchers