Tides about New Zealand
Tides account for about 95% of the variation in sea level on the New Zealand coast. The nature of the tides varies considerably from place to place around New Zealand. The tidal range varies around New Zealand for spring tides and neap tides. For instance spring tides in Golden Bay have a 4 m range while those at Kaikoura can be as little as 1 m. The rising and falling tide we observe at the beach comprises many different tides (or constituents) of various strengths and cycle times each resulting from a particular feature of the gravitational attraction by the Moon and Sun on Earth’s waters. A computer tidal model build by NIWA to simulate tides shows how the major M2 constituent tide progresses anticlockwise about the coast of New Zealand. NIWA’s tide forecaster is used to forecast high and low tides anywhere in open coastal and ocean waters around New Zealand for up to 28 days. It also predicts historical tides back to 1830.
Lunar Semidiurnal Tide (M2)
This animation of the M2 tide may take a minute or two to load, during which time the frames will refresh one by one. When it is complete you will see the a continuous cycle from high tide (red) through zero (green) to low tide (blue), then back through zero to high tide again.