A Note on the Instability of the African Easterly Jet

Abstract

Abstract A stability analysis has been performed for an easterly lower tropospheric jet which approximates the observed flow over West Africa during summer. The most unstable disturbance has a growth rate of 0.27 day?1, a wavelength close to 4000 km and a phase speed of about 9 m s?1. Although gross features of its energetics are similar to those found by Rennick in a recent theoretical study, there are significant differences in horizontal structure. The present results appear to be in closer agreement with observation.