htides

htides is a term that refers to the harmonic tides, which are the theoretical tidal components that result from analyzing tidal observations using Fourier analysis. These components represent predictable, periodic fluctuations in sea level caused by the gravitational forces of the Moon and Sun, as well as other astronomical factors.

When tidal data is analyzed, it can be broken down into a series of simple harmonic constituents, each with a specific frequency, amplitude, and phase. The most significant constituents include the semi-diurnal (like M2, S2) and diurnal (like K1, O1) tides, which correspond to the Earth's rotation and the orbital periods of the Moon and Sun. By summing these individual harmonic components, a predicted tide curve can be generated.

The concept of harmonic tides is fundamental to tidal prediction. Oceanographers and meteorologists use these harmonic constituents to forecast tidal heights at various locations around the world. Understanding and calculating these components allows for the prediction of phenomena such as high tide, low tide, and tidal currents with a high degree of accuracy, which is crucial for navigation, coastal engineering, and marine research. The amplitudes and phases of these harmonic constituents vary regionally due to local geographical features like coastlines and ocean basin shapes.