Health is wealthHeight of Water Tides
The astronomical data is not sufficient to calculate tides. However the predictions are based on actual tidal measurements in many areas over an extended period. A network of tide stations is equipped to take the following measurements every six minutes: tide levels, wind speed, wind direction, water current speeds, directions, air and water temperatures and barometric pressure. Stations that provide these daily predictions are called reference stations. Other stations are subordinate stations, which obtain predictions by applying a specific formula to this data. The formula is derived by observing how tides at the two stations related to one another in the past.
