How can tide tables be produced so accurately?
There are many different steps involved in obtaining the final numbers that go into a tide table. Before a tidal prediction can be made for a port, a long sequence of tidal observations for that port are needed (called a time series). This time series will include all the astronomical effects and local coastline/depth effects (which make up the tide) as well as the weather induced effects called the surge (see question 1). As shown in questions 6 and 8, there are certain frequencies that are known to occur in the tide. Some of these are listed below: 12 hour (12:00:00.0) repeated pattern (cycle) due to the gravity of the sun. 12:25:14.164 cycle due to the gravity of the moon. 24:00 and 24:50:28.328 cycles caused by the differences in the two tidal bulges. 27.2122 day cycle caused by change in lunar declination (Moons angle to the Earth). 27.5546 day cycle caused by a regular change in the Earth-Moon distance. 29.5306 day cycle caused by the phases of the moon (see question 8). Each of
