[Portal] Oceans

The Oceans Portal
A portal dedicated to oceans, seas, oceanography and related topics

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Surface view of the Atlantic Ocean

An ocean is a body of water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. The phrases "the ocean" or "the sea" used without specification refer to the interconnected body of salt water covering the majority of the Earth's surface. As a general term, "the ocean" is mostly interchangeable with "the sea" in American English, but not in British English. Strictly speaking, a sea is a body of water (generally a division of the world ocean) partly or fully enclosed by land.

Waves in Pacifica, California

The sea, the world ocean, or simply the ocean is the connected body of salty water that covers about 70% of Earth's surface (361,132,000 square kilometres [139,434,000 sq mi]), with a total volume of roughly 1,332,000,000 cubic kilometres [320,000,000 cu mi]. It moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. It has been travelled and explored since ancient times, while the scientific study of the sea—oceanography—dates broadly from the voyages of Captain James Cook to explore the Pacific Ocean between 1768 and 1779. The word sea is also used to denote smaller, partly landlocked sections of the ocean and certain large, entirely landlocked, saltwater lakes, such as the Caspian Sea and the Dead Sea.

Oceanography (compound of the Greek words ὠκεανός meaning "ocean" and γράφω meaning "write"), also known as oceanology, is the study of the physical and biological aspects of the ocean. It is an important Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within: astronomy, biology, chemistry, climatology, geography, geology, hydrology, meteorology and physics. Paleoceanography studies the history of the oceans in the geologic past. An oceanographer is a person who studies many matters concerned with oceans including marine geology, physics, chemistry and biology.

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Breaking swell waves at Hermosa Beach, California
A swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air and thus are often referred to as surface gravity waves. These surface gravity waves are not wind waves, which are generated by the immediate local wind, but instead are generated by distant weather systems, where wind blows for a duration of time over a fetch of water. More generally, a swell consists of wind-generated waves that are not—or are hardly—affected by the local wind at that time. Swell waves often have a long wavelength, but this varies due to the size, strength, and duration of the weather system responsible for the swell and the size of the water body. Swell wavelength also varies from event to event. Occasionally, swells that are longer than 700m occur as a result of the most severe storms. Swell direction is the line or course on which the swell is moving. It is measured in degrees (as on a compass), and often referred to in general directions from which it is coming, such as an NNW or SW swell. Swells have a narrower range of frequencies and directions than locally generated wind waves, because they have dispersed from their generation area and dissipated. Swells take on a more defined shape and direction and are less random than locally generated wind waves. Read more...
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Painting of two sailing ships, sails fully rigged, exchanging cannonfire on a choppy blue-green sea

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Admiralty law

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