A modified response analysis in the form of an orthotide parametrizati
on is used to derive major semi-diurnal and diurnal tidal constituents
over the Newfoundland and Scotian Shelves from TOPEX/POSEIDON altimet
er data. The orthotide formulation simultaneously solves for eight maj
or semi-diurnal and diurnal constituents, and has an accuracy of bette
r than similar to 1.5 cm for each constituent. Tidal elevations are de
rived from the altimeter data on the ascending and descending satellit
e ground tracks, and interpolated using the method of statistical inte
rpolation. The semi-diurnal constituents (M(2), S-2 and N-2) compare f
avourably with available in-situ observations and a numerical model. T
he diurnals (K-1 and O-1) are not as accurate as the semi-diurnals, es
pecially in the nearshore environment. The paper demonstrates the abil
ity of TOPEX/POSEIDON altimetry to provide accurate tidal data over a
continental shelf.