Multiplicity of time-periodic solutions and their stabilities for quasigeostrophic equations

In this article, we study the quasigeostrophic equation, which is a prototypical geophysical fluid model. We will show the existence of multiple time-periodic solutions and study their stabilities.We also prove the exponential decaying of solutions to the initial value problem with small initial data. © 2006 Elsevier Inc. All rights reserved