Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and are also caused by the Earth and Moon orbiting one another.
Barrier islands are a coastal landform, a type of dune system and sand island, where an area of sand has been formed by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a few islands to more than a dozen. They are subject to change during storms and other action, but absorb energy and protect the coastlines and create areas of protected waters where wetlands may flourish. A barrier chain may extend for hundreds of kilometers, with islands periodically separated by tidal inlets. The largest barrier island in the world is Padre Island of Texas, United States, at 113 miles (182 km) long. Sometimes an important inlet may close permanently, transforming an island into a peninsula, thus creating a barrier peninsula, often including a beach, barrier beach. Though many are long and narrow, the length and width of barriers and overall morphology of barrier coasts are related to parameters including tidal range, wave energy, sediment supply, sea-level trends, and basement controls. The amount of vegetation on the barrier has a large impact on the height and evolution of the island.
A rip current is a specific type of water current that can occur near beaches where waves break. A rip is a strong, localized, and narrow current of water that moves directly away from the shore by cutting through the lines of breaking waves, like a river flowing out to sea. The force of the current in a rip is strongest and fastest next to the surface of the water.
A rip tide, or riptide, is a strong offshore current that is caused by the tide pulling water through an inlet along a barrier beach, at a lagoon or inland marina where tide water flows steadily out to sea during ebb tide. It is a strong tidal flow of water within estuaries and other enclosed tidal areas. The riptides become the strongest where the flow is constricted. When there is a falling or ebbing tide, the outflow water is strongly flowing through an inlet toward the sea, especially once stabilised by jetties.
Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.
Narragansett Bay is a bay and estuary on the north side of Rhode Island Sound covering 147 square miles (380 km2), 120.5 square miles (312 km2) of which is in Rhode Island. The bay forms New England's largest estuary, which functions as an expansive natural harbor and includes a small archipelago. Small parts of the bay extend into Massachusetts.
HMS Conway was a naval training school or "school ship", founded in 1859 and housed for most of her life aboard a 19th-century wooden ship of the line. The ship was originally stationed on the Mersey near Liverpool, then moved to the Menai Strait during World War II. While being towed back to Birkenhead for a refit in 1953, she ran aground and was wrecked, and later burned. The school moved to purpose-built premises on Anglesey where it continued for another twenty years.
The Port River is part of a tidal estuary located north of the Adelaide city centre in the Australian state of South Australia. It has been used as a shipping channel since the beginning of European settlement of South Australia in 1836, when Colonel Light selected the site to use as a port. Before colonisation, the Port River region and the estuary area were known as Yerta Bulti by the Kaurna people, and used extensively as a source of food and plant materials to fashion artefacts used in daily life.
A tide clock is a specially designed clock that keeps track of the Moon's apparent motion around the Earth. Along many coastlines, the Moon contributes the major part (67%) of the combined lunar and solar tides. The exact interval between tides is influenced by the position of the Moon and Sun relative to the Earth, as well as the specific location on Earth where the tide is being measured. Due to the Moon's orbital prograde motion, it takes a particular point on the Earth 24 hours and 50.5 minutes to rotate under the Moon, so the time between high lunar tides fluctuates between 12 and 13 hours. A tide clock is divided into two roughly 6 hour tidal periods that shows the average length of time between high and low tides in a semi-diurnal tide region, such as most areas of the Atlantic Ocean.
The Moskstraumen or Moskenstraumen is a system of tidal eddies and whirlpools, one of the strongest in the world, that forms at the Lofoten archipelago in Nordland county, Norway between the Norwegian Sea and the Vestfjorden. It is located between the Lofoten Point on the island of Moskenesøya and the island of Mosken. Moskstraumen is unusual in that it occurs in the open sea whereas most other whirlpools are observed in confined straits or rivers. It originates from a combination of several factors, the dominant being the strong semi-diurnal tides and peculiar shape of the seabed, with a shallow ridge between the Moskenesøya and Værøya islands which amplifies and whirls the tidal currents.
The Gawler River is a river located in the Adelaide Plains district of the Mid North region in the Australian state of South Australia.
The following outline is provided as an overview of and introduction to Oceanography.
French Pass is a narrow and treacherous stretch of water that separates D'Urville Island, at the north end of the South Island of New Zealand, from the mainland coast. At one end is Tasman Bay, and at the other end the outer Pelorus Sound / Te Hoiere leads out to Cook Strait.
New Zealand has large ocean energy resources but does not yet generate any power from them. TVNZ reported in 2007 that over 20 wave and tidal power projects are currently under development. However, not a lot of public information is available about these projects. The Aotearoa Wave and Tidal Energy Association was established in 2006 to "promote the uptake of marine energy in New Zealand". According to their 10 February 2008 newsletter, they have 59 members. However, the association doesn't list its members.
In hydrology, a current in a stream or other water body is the flow of water influenced by gravity as the water moves downhill to reduce its potential energy. The current varies spatially as well as temporally within the stream, dependent upon the flow volume of water, stream gradient, and channel geometry. In tidal zones, the current and streams may reverse on the flood tide before resuming on the ebb tide.
A tidal prism is the volume of water in an estuary or inlet between mean high tide and mean low tide, or the volume of water leaving an estuary at ebb tide.
Estuarine water circulation is controlled by the inflow of rivers, the tides, rainfall and evaporation, the wind, and other oceanic events such as an upwelling, an eddy, and storms. Estuarine water circulation patterns are influenced by vertical mixing and stratification, and can affect residence time and exposure time.
A tidal barrage is a dam-like structure used to capture the energy from masses of water moving in and out of a bay or river due to tidal forces.
A floating dock, floating harbour or wet dock is a dock alongside a tidal waterway which maintains a 'constant' level, despite the changing tides.
Nonlinear tides are generated by hydrodynamic distortions of tides. A tidal wave is said to be nonlinear when its shape deviates from a pure sinusoidal wave. In mathematical terms, the wave owes its nonlinearity due to the nonlinear advection and frictional terms in the governing equations. These become more important in shallow-water regions such as in estuaries. Nonlinear tides are studied in the fields of coastal morphodynamics, coastal engineering and physical oceanography. The nonlinearity of tides has important implications for the transport of sediment.
