Abstract
The two-layer model of baroclinic instability is modified to include small continuous variations of the velocity/density profile in the upper layer. It is demonstrated that, if the difference between the average upper-layer velocity and the velocity in the lower layer is negative (westward), the flow is unstable. The instability takes place in the spectral region of waves with critical levels, but the unstable disturbances do not have the logarithmic singularity, which is commonly believed to destabilize the flow through rapid variation of heat flux. The instability is interpreted as a resonance between Rossby waves and a certain “shear mode” supported by the vertical shear of the mean flow.
| Original language | English (Ireland) |
|---|---|
| Pages (from-to) | 95-113 |
| Number of pages | 19 |
| Journal | Geophysical and Astrophysical Fluid Dynamics |
| Volume | 78 |
| Issue number | 1-4 |
| DOIs | |
| Publication status | Published - 1 Dec 1994 |
Keywords
- Baroclinic instability
- critical levels
- two-layers model