King tide

A king tide is an especially high

spring tide, especially the perigean spring tides

which occur three or four times a year. King tide is not a scientific term, nor is it used in a scientific context.

The expression originated in Australia, New Zealand and other Pacific nations to describe especially high tides that occur a few times per year. It is now used in North America as well,^[1] particularly in low-lying South Florida, where king tides can cause tidal flooding. In Vancouver, Canada, king tides are a growing problem along its seawall.^[2]

Definition

King tides are the highest tides. They are naturally occurring, predictable events.

Tides are the movement of water across

gravitational forces exerted by the Moon, Sun

, and the rotation of Earth which manifest in the local rise and fall of sea levels. Tides are driven by the relative positions of the Earth, Sun, Moon, land formations, and relative location on Earth. 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 alignment. These highest tides in the lunar cycle are called spring tides.

The proximity of the Moon in relation to Earth and Earth in relation to the Sun also has an effect on tidal ranges. The Moon moves around Earth in an

gravitational force

is greatest when the Earth is at perihelion – closest to the Sun in early January – and least when the Earth is at aphelion – farthest from the Sun in early July.

The king tides occur at new and full moon when the Earth, Moon and Sun are aligned at perigee and

perihelion, resulting in the largest tidal range seen over the course of a year. So, tides are enhanced when the Earth is closest to the Sun around January 2 of each year. They are reduced when it is furthest from the Sun, around July 2.^[3]

The predicted heights of a king tide can be further augmented by local weather patterns and ocean conditions.

References

General references

tidesandcurrents.noaa.gov

Inline citations

^ "Hurricanes leave Florida coasts vulnerable to 'King tides'". The Big Story. Archived from the original on 2016-10-18. Retrieved 2016-10-14.
^ "CityNews".
^ Tidal Variations - The Influence of Position and Distance NOAA ocean service education

External links

EPA King Tides Factsheet
EPA page on king tides and climate change
oceanservice.noaa.gov – NOAA National Ocean Service
NOAA tool for predicting tide events –
Tides and water levels – NOAA tides tutorial
King tides photo initiative – North Carolina, US
King tides photo initiative – Washington State, US
King tides photo initiative – Oregon, US
King tides photo initiative – Long Island Sound, US
King tides photo initiative – Barnegat Bay, US
King tides photo initiative – Australia
King tides photo initiative – New South Wales, Australia
www.thesinkingoftuvalu.com – King Tide / The Sinking of Tuvalu
King tides photo initiative – Hawaii and Pacific Islands King Tides Project

[1] "Hurricanes leave Florida coasts vulnerable to 'King tides'". The Big Story. Archived from the original on 2016-10-18. Retrieved 2016-10-14.

[2] "CityNews".

[3] Tidal Variations - The Influence of Position and Distance NOAA ocean service education

[1]

[2]

[3]

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