Solutions are obtained for quasigeostrophic free oscillations in enclosed basins of dimensions comparable to the Pacific, Atlantic, and Indian oceans. The lower-order baroclinic oscillations are r estri cted to the regions adjacent to the eq uator or the ocean boundaries, and for each basin the oscillations have an estimated minimum period of about 20 days. The barotropic oscillations fill the complete basin and have minimum periods varying from an estimated 2.7 days in the Pacific Ocean (wave length 14,900 km) to 3.8 days in the Indian Ocean (wave length 10,400 km)....
Rattray, Maurice, and Robert L. Charnell. 1966. "Quasigeostrophic free oscillations in enclosed basins." Journal of Marine Research 24, (1). https://elischolar.library.yale.edu/journal_of_marine_research/1066