Abstract: The low-frequency vortex dipoles, namely, the Sri Lanka Dome (SLD) and Anticyclonic Eddy (AE), a recurring phenomenon that is generated during southwest monsoon season east of Sri Lanka, have great influences on local ecosystem and climate. A recently developed multiscale analysis methodology is used to investigate the genesis and evolution mechanisms underlying the low-frequency vortex dipoles, on the basis of the HYCOM reanalysis data with a horizontal resolution of (1/12.5)°. It is found that the dynamical processes of the two eddies are similar, with the ultimate driving force traced back to the wind stress. They may, however, choose one or more of the following three completely different energy pathways: ①eddies are directly driven by the wind; ②the wind first drives the background southwest monsoon current (SMC), while the SMC feeds the eddies via a barotropic instability; ③the SMC obtains energy from the wind, and then convert that part of kinetic energy to available potential energy (APE), which through a baroclinic instability is transferred to eddy APE, facilitating the growth of the eddies. The two eddies may decay due to either a reduction in strength of the external wind forcing, or a weakening of the barotropic instability of the background flow, or a nonlocal dispersion of the eddy energy, or an intense dissipation through forward energy cascading.