Part 5 — Instabilities
Where the energy for storms and eddies actually comes from. Barotropic instability draws on horizontal shear; baroclinic instability — the single most consequential instability in this subject — draws on the potential energy locked in a sloping temperature surface. Closes with the faster, more local mechanisms that matter at fronts and in stratified shear layers: symmetric, inertial, and Kelvin–Helmholtz instability.