tides & currents
We have selected National Oceanic & Atmospheric Administration as the world's very best website on Tides & Currents.
The National Oceanic & Atmospheric Administration publishes a website on Tides and Currents. It is organized into the following six sections: Introduction, Astronomical Tide-Producing Forces, Differential Tide-Producing Forces, Variations in the Ranges of the Tides, Local Height and Times of Tides, and Prediction of Tides.
The website explains that the earth's gravitational force acts inwards to hold the water of the oceans to its surface, but the gravitational forces of the moon and the sun also act on the earth's ocean waters. They exert tractive forces, which tend to draw the ocean waters to positions on the earth's surface directly below them, creating tidal movements. These points are known as sublunar and subsolar points.
The website includes a zoomable map of the coastline around the USA, linked to a database of information on Tide Data, Tide Predictions, and Historic Tide Data for numerous observation points.