Publié par AFTER Beach dans Blog AFTER Beach – AFTER Beach France le 31/03/2017 à 00:00
With our Celtic origins, we it essential for us to blog about high tides which are so spectacular in Brittany, especially during the equinoxes, perfect times for fishing and collecting shells.
The equinox tides
The equinox is the time of year when the sun reaches its zenith at the equator. At this moment, the earth is at right angles (from the poles) with the sun's rays. Day and night last the same time. Between the months of March and September, when night and day are the same, a phenomenon called the equinox tide occurs, when the sea recedes very far and the tides are stronger. It is a period that attracts fishermen, but it is also feared by residents, because of the high risk of flooding.
When the plane of the earth’s equator passes through the geometric centre of the Sun’s disk, the tides become more powerful. As for the movement of the stars, the same law applies: the law of gravitation. The reciprocal attraction of the moon and the sun causes the waters to move. The earth’s mass attracts the moon which remains in orbit and vice versa, the moon’s mass creates a force that draws the earth and the oceans towards it. This is gravity. The tidal coefficient can reach 105 during equinox tides. During the summer or winter solstices, the sun is far from the plane of the equator, the tides are lower with a coefficient of less than 100.
The solstice is the time of year when the sun's rays hit the Earth at the most tilted angle. The summer solstice is the longest day and the winter solstice is the shortest.
The tides of the century
Every four and a half years, the equinox tides are particularly strong, a phenomenon that can occur several times in a century, with the sea receding very far. Tides of the century can reach coefficients of between 118 to 120.
The site: SHOM is a free site for information out about tide times around the world (Marine Hydrographic and Oceanographic Service).