Tidal datum that is the arithmetic mean of the low water heights observed over a specific 19-year Metonic cycle (National Tidal Datum Epoch). For stations with shorter series, simultaneous observations are made with a primary control tide station to derive the equivalent of a 19-year value. Use of "mean low tide" is discouraged.
the average level of low tide for any area.
The average height of the low tides over a 19-year period.
A tidal datum. The higher of the two low water levels in a tidal cycle. visual
The average level of low water at a place over a 19 year period.