How are tides modelled with trig?
Tide height rises and falls roughly sinusoidally: h(t) = A·sin(2πt/T) + mean, where A is the tidal amplitude, T the period, and mean the average sea level.
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Tide Height Prediction
Estimate tide height at any time with h(t) = A·sin(2πt/T) + mean level, with the tidal phase angle in degrees or radians.
h(t) = A·sin(2πt/T) + mean
Angle unit
Frequently asked questions
What is the tidal period?
A semi-diurnal tide repeats about every 12.42 hours — two highs and two lows a day — set by the Moon's motion.
Can you show a worked example?
With A = 2 m, T = 12.42 h, mean 3 m, a quarter-period in (t ≈ 3.105 h) reaches high tide: h = mean + A = 5 m.
What are the high and low marks?
High tide = mean + A, low tide = mean − A. Here that is 5 m and 1 m.
Is this exact?
It is a single-harmonic estimate. Real tide tables combine many harmonic terms for the Moon, Sun and local effects, so use official tables for navigation.