Further Development of a Theory of Lee Cyclogenesis

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  • 1 Yale University, New Haven, CT 06511
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Abstract

The purpose of this paper is to further develop, and then apply, the “lee wave” theory of lee cyclogenesis described by Smith. The two-dimensional time-dependent quasi-geostrophic theory is shown to give closed form asymptotic solutions which clarify the cyclone growth mechanism and the catalytic influence of orography. Ageostrophic effects are considered and found to have little influence on the Ice cyclone unless a low lying inertial wave critical layer is present. When a rigid lid is added to the model thus allowing baroclinic instability, a rapid two-phase cyclone growth is found. Without a resonant orographic phase, the unstable growth is small. The theory is applied to three mountain ranges: the Alps, the Colorado Rockies, and the southern Appalachians. The results suggest that the “iee wave” model may be partially correct in the first two regions but Problematic in the third.

Abstract

The purpose of this paper is to further develop, and then apply, the “lee wave” theory of lee cyclogenesis described by Smith. The two-dimensional time-dependent quasi-geostrophic theory is shown to give closed form asymptotic solutions which clarify the cyclone growth mechanism and the catalytic influence of orography. Ageostrophic effects are considered and found to have little influence on the Ice cyclone unless a low lying inertial wave critical layer is present. When a rigid lid is added to the model thus allowing baroclinic instability, a rapid two-phase cyclone growth is found. Without a resonant orographic phase, the unstable growth is small. The theory is applied to three mountain ranges: the Alps, the Colorado Rockies, and the southern Appalachians. The results suggest that the “iee wave” model may be partially correct in the first two regions but Problematic in the third.

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