Left column illustrates the model for reference with the setup in Section 5.1, showing the diffusivity profiles (upper panel), the steady-state solution (middle panel), and the perturbation modes (lower panel). The growth rates are ν _sym = −0.10 and ν _asy = 0.035. Right two columns present the dependence of ν _sym (orange lines) and ν _asy (blue lines) on different parameters: β ₀, ζ _t , α _O0, and ﹩{\left({\alpha }_{{\rm{A}}}/{b}^{2}\right)}_{0}﹩ (see Section 5.2). Note that negative values are shown in dashed lines. The vertical dotted lines are plotted in each panel, indicating the value taken by the reference model.