Ssa is a meteorological tide. Not in tidal potential forcing. Correction: it is both!
requested to merge extdevs/nemo:583_SSA_tidal_potential into 583-review-of-the-tidal-constituent-parameters
Ssa is a meteorological tide (semi annual). update and also occurs in the development of the solar gravitational force. So we set the equilibrium tidal amplitude to non-zero to account for the gravitational component, and expect that a meteorological component will/can also be excited at the same frequency.
NB Sa and S1 also appear in the development of the solar gravitational force. However their contribution is small (4th power in solar parallax exansion) so are considered a Meteorological constituents only. (See Schureman58 p47).
Edited by jeff polton