We show that sufficiently small mild solutions of the initial value problem to the quasi-geostrophic equation in $\mathbb R^2$ are asymptotically stable under arbitrary large initial $L^2$-perturbations. We obtain also the decay rate.
"Asymptotic stability of solutions to quasi-geostrophic equation." Bull. Belg. Math. Soc. Simon Stevin 24 (2) 189 - 198, april 2017. https://doi.org/10.36045/bbms/1503453705