King tide
Encyclopedia
King tide is the popular name for an especially high tide
. The phrase is used mostly in Australia
, New Zealand
and other Pacific
nations.
In the lunar month, the highest tides occur roughly every 14 days, at the new and full moons, when the gravitational pull of the moon and the sun are in line. These are called spring tides.
The earth moves around the sun in an elliptical orbit that takes a little over 365 days to complete. The sun has an influence on the tides. Its gravitational force is greatest when the earth is closest to the sun (perihelion – early January) and least when the sun is farthest from earth (aphelion – early July).
The moon has a larger effect on the tides than the sun. The moon moves around the earth in an elliptical orbit that takes about 29 days to complete. The gravitational force is greatest when the moon is closest to the earth (perigee) and least when it is farthest from the earth (apogee – about two weeks after perigee).
The king tides occur when the Earth, moon and sun are aligned at perigee
and perihelion. On Australia's East Coast, the highest tides occur during the winter months of June, July and August, and the summer months of December, January and February. The highest of each of these periods (i.e., one in winter and one in summer, totaling two per year) are known as the king tides.
The winter king tide usually occurs at night and therefore goes unnoticed. Consequently the summer king tide usually catches the most attention. On such days the surf is particularly dangerous — tall waves, long clean breaks, strong rips, consistent sets: ideal for surfing, but seductive and dangerous for inexperienced swimmers.
King tides are particularly formidable on the island country of Tuvalu
, where they can devastate the low lying atoll
's people and wildlife. Sea level rise may exacerbate these effects.
As with all spring tides, king tides occur with the coming of new and full moons. Some traditional mythologies hold that such times cause madness, a possible origin of the word "lunacy".
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
. The phrase is used mostly in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and other Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
nations.
In the lunar month, the highest tides occur roughly every 14 days, at the new and full moons, when the gravitational pull of the moon and the sun are in line. These are called spring tides.
The earth moves around the sun in an elliptical orbit that takes a little over 365 days to complete. The sun has an influence on the tides. Its gravitational force is greatest when the earth is closest to the sun (perihelion – early January) and least when the sun is farthest from earth (aphelion – early July).
The moon has a larger effect on the tides than the sun. The moon moves around the earth in an elliptical orbit that takes about 29 days to complete. The gravitational force is greatest when the moon is closest to the earth (perigee) and least when it is farthest from the earth (apogee – about two weeks after perigee).
The king tides occur when the Earth, moon and sun are aligned at perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
and perihelion. On Australia's East Coast, the highest tides occur during the winter months of June, July and August, and the summer months of December, January and February. The highest of each of these periods (i.e., one in winter and one in summer, totaling two per year) are known as the king tides.
The winter king tide usually occurs at night and therefore goes unnoticed. Consequently the summer king tide usually catches the most attention. On such days the surf is particularly dangerous — tall waves, long clean breaks, strong rips, consistent sets: ideal for surfing, but seductive and dangerous for inexperienced swimmers.
King tides are particularly formidable on the island country of Tuvalu
Tuvalu
Tuvalu , formerly known as the Ellice Islands, is a Polynesian island nation located in the Pacific Ocean, midway between Hawaii and Australia. Its nearest neighbours are Kiribati, Nauru, Samoa and Fiji. It comprises four reef islands and five true atolls...
, where they can devastate the low lying atoll
Atoll
An atoll is a coral island that encircles a lagoon partially or completely.- Usage :The word atoll comes from the Dhivehi word atholhu OED...
's people and wildlife. Sea level rise may exacerbate these effects.
As with all spring tides, king tides occur with the coming of new and full moons. Some traditional mythologies hold that such times cause madness, a possible origin of the word "lunacy".