A station with enough observations to compute reliable harmonic constants, whose daily predictions are printed in full in tide or current tables. Predictions for many smaller places, the subordinate stations, are derived from a nearby reference station by applying time and height differences. Choosing a reference station with a similar tide type is essential, or the corrections break down.
Use the harbour entrance as the reference station, its curve looks like ours, the city pier doesn't.
Also heard as
- standard port
- primary station
- harmonic station
Related terms
Subordinate station
A location whose tides are predicted by applying time and height corrections to a nearby reference station.
Tidal prediction
A forecast of tide heights or currents computed from harmonic constants and astronomy, with no weather included.
Harmonic analysis
Breaking an observed water level or current record into its tidal constituents to find each one's amplitude and phase.
Simultaneous comparison
Computing datums at a short-term station by comparing its record with a long-term control station over the same days.