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.
Some shorelines experience two almost equal high tides and two low tides each day, called a semi-diurnal tide. Some locations experience only one high and one low tide each day, called a diurnal tide. Some locations experience two uneven tides a day, or sometimes one high and one low each day; this is called a mixed tide. The times and amplitude of the tides at a locale are influenced by the alignment of the Sun and Moon, by the pattern of tides in the deep ocean, by the amphidromic systems of the oceans, and by the shape of the coastline and near-shore bathymetry (see Timing).
Tides vary on timescales ranging from hours to years due to numerous influences. To make accurate records, tide gauges at fixed stations measure the water level over time. Gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the reference (or datum) level usually called mean sea level.
While tides are usually the largest source of short-term sea-level fluctuations, sea levels are also subject to forces such as wind and barometric pressure changes, resulting in storm surges, especially in shallow seas and near coasts.
Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present. For example, the solid part of the Earth is affected by tides, though this is not as easily seen as the water tidal movements.
Other articles related to "high water, high, water":
... The highest NAV of a fund to date is known as the "high water mark" ... If the NAV subsequently increases over the following year back to the high water mark (but no higher), it would be objectionable for the investor to be charged a performance fee on that increase because the ... performance fee on increases in NAV over the high water mark ...
... High water is a the time in a tidal system when the tide is highest ... High water may also refer to High Water, an album credited to The Fabulous Thunderbirds High Water, a 2004 album by El-P "High Water", a song by Uncle Tupelo from their 1993 ...
... The seasonal changes in the Columbia's flow, high in summer and low in winter, affected Celilo Falls dramatically ... Celilo Falls in the late autumn when the water was relatively low, turning the falls into a major barrier ... In contrast, when David Thompson passed Celilo Falls in July 1811, the high water obscured the falls and made his passage through the Columbia Gorge relatively easy ...
... The term, "high water mark" has been used as a metaphor for the maximum extent of geographic control of an occupier of territory, and later for the maximum level of power, popularity, or some ... Some examples of metaphorical usage include High-water mark of the Confederacy, the turning point of the Battle of Gettysburg ... High Water Mark of the Rebellion Monument, a Gettysburg Battlefield memorial ...
... High Water Liverpool that morning was 1118 am, height 32'10" and the highest tide that year (Admiralty Tide Tables) Lavers Almanac quote HW Menai Bridge ... What is termed High Water 'Slack' in the Swellies is actually a brief period of uneasy equilibrium between two opposing flood streams which typically occurs 1 hour 42 minutes before local High Water ... give the false result that the ship would not have the water over the rock until L.pool -2.00 (0918) ...
Famous quotes containing the words water and/or high:
“The work of the world is common as mud.
Botched, it smears the hands, crumbles to dust.
But the thing worth doing well done
has a shape that satisfies, clean and evident.
The pitcher cries for water to carry
and a person for work that is real.”
—Marge Piercy (b. 1936)
“That is very high praise, which is given you by faithful witness.”
—Plato (c. 427347 B.C.)