Equatorially trapped vertically propagating Rossby-gravity waves have been observed in the Gulf of Guinea. Analyses of their kinematics, dynamics, and energetics are presented. The particular packet considered had band central values for period, zonal wavelength, and vertical wavelength of 31 days, 1220 km, and 990 m respectively. The phase propagation was westward and upward while the energy flux was eastward and downward. The calculated trapping (efolding) scale was 210 km. Therefore, the waves were unaffected by the zonal African coast situated some 500 km to the north....
Weisberg, R. H., A. Horigan, and C. Colin. 1979. "Equatorially trapped Rossby-gravity wave propagation in the Gulf of Guinea." Journal of Marine Research 37, (1). https://elischolar.library.yale.edu/journal_of_marine_research/1460