Polar-wave deformation-radius identifiability
= Polar-wave deformation-radius identifiability
For a <polar gamma-plane Rossby wave>, the drift fixes $\alpha^2=K^2+L_d^{-2}$. It does not separately fix radial <wavenumber> $K$ and <Rossby deformation radius> $L_d$. Scaling an eigenfunction changes its amplitude without changing either wavenumber, so a meander amplitude cannot supply the missing radial wavelength. A radial boundary condition or a separately justified envelope approximation is needed to determine $L_d$.