Abstract
The stability of planetary waves in a two-layer fluid system is investigated in the small local Rossby number M limit. The problem presents a simple example of non-linear resonant instability discussed by Hasselmann (1967). The energy transfer mechanism of the instability is clarified. Some implications on energy and enstrophy cascade in planetary fluids are discussed. The analysis is complementary to the preceding paper of Yamagata (1976).
