Figure 1

Figure 1: Ocean tide models have been improved in shallow water regions using TOPEX/POSEIDON altimetry. In the North Sea the M4 tidal constituent, which has a period of about six hours, is considerable. The proposed tandem mission of Jason-1 and TOPEX/POSEIDON (interleaved ground tracks) will provide a unique opportunity to improve on those models. a) Amplitude in centimetres, b) Phase in degrees.