Australian National Tide Tables.
Related Terms 
LIMNIMETER
A type of tide gage for measuring lake level variations.

HALFTIDE BASIN
A lock of very large size and usually of irregular shape, the gates of which are kept open for several hours after high tide so that vessels may enter as long as there is sufficient depth over the sill. Vessels remain in the halftide basin until the ensuing flood tide before they may pass through the gate to the inner harbor. If entry to the inner harbor is required before this time, water must be admitted to the halftide basin from some external source.

HARMONIC FUNCTION
Any real function that satisfies a certain equation. In its simplest form, as used in tide and tidal current predictions, it is a quantity that varies as the cosine of an angle that increases uniformly with time

HARMONIC CONSTANTS
The amplitudes and epochs of the harmonic constituents of the tide or tidal current at any place

HIGH WATER
The maximum height reached by a rising tide. The height may be due solely to the periodic tidal forces or it may have super imposed upon it the effects of prevailing meteorological condi tions. Use of the synonymous term HIGH TIDE is discouraged.

HALFTIDE LEVEL
A tidal datum midway between mean high water and mean low water. Mean sea level may coincide with halftide level, but seldom does; the variation is generally about 3 centimeters and rarely exceeds 6 centimeters. Also called MEAN TIDE LEVEL.

HALF TIDE
The condition or time of the tide when midway between high and low

HARMONIC PREDICTION
Method of predicting tides and tidal currents by combining the harmonic constituents into a single tide curve, usually performed by computer.

HIGH WATER MARK
A line or mark left upon tide flats, beach, or alongshore objects indicating the elevation of the intrusion of high water. It should not be confused with the MEAN HIGH WATER LINE or MEAN HIGHER HIGH WATER LINE

HARMONIC ANALYSIS
The process by which the observed tide or tidal current at any place is separated into basic harmonic constituents. Also called HARMONIC REDUCTION.
