Equatorial Kelvin Wave Instability and the Wind-Evaporation Feedback Mechanism

Abstract

By Han-Ru Cho, Pay Liam Lin, and Jough Tai Wang Institute of Atmospheric Physics National Central University Chungli, Taiwan 320

Instability of the Kelvin waves problem is analyzed using the wind-evaporation feedback mechanism as the cumulus parameterization scheme. The method we used is a modified method of characteristics (LeVeque, 1992). Two cases are considered, First we considered a linear case without assuming any background wind. The instability depends not only on direction of the perturbation wind, but also depends on what height level we are dealing with. Next, we calculated the linear case with a background wind in the zonal direction. This is identical to the case analyzed by Neelin et al. (1987). However, our instability criteria is much more complex than theirs, due to our added dimension (in the vertical direction). No direct comparisons are possible because of the shallow water system they used.