Abstract
A two-layer quasi-geostrophic model forced by surface friction and radiative relaxation to a jetlike wind profile can exist in either a wave-free state or in a finite-amplitude wave state, over a substantial region of the models parameter space. Weakly unstable waves are found that do not stabilize the flow; instead, their growth rate increases with wave amplitude. We explain this is terms of 1) the competition between the stabilizing effect of the lower-layer potential vorticity fluxes and the destabilizing effect of nonlinear critical layer formation associated with the upper-layer fluxes, and 2) the tendency of surface drag to restore the vertical shear at the center of the jet by damping the surface westerlies generated by the baroclinic instability. -from Authors
Original language | English (US) |
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Pages (from-to) | 1071-1077 |
Number of pages | 7 |
Journal | Journal of the Atmospheric Sciences |
Volume | 48 |
Issue number | 8 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Atmospheric Science