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Mooring (oceanography)
A mooring in oceanography is a collection of devices connected to a wire and anchored on the sea floor. It is the ''Lagrangian and Eulerian specification of the flow field, Eulerian way'' of measuring ocean currents, since a mooring is stationary at a fixed location. In contrast to that, the ''Lagrangian way'' measures the motion of an oceanographic Drifter (floating device), drifter, the Lagrangian drifter. Construction principle The mooring is held up in the water column with various forms of buoyancy such as Glass float, glass balls and syntactic foam floats. The attached instrumentation is wide-ranging but often includes Conductivity, temperature, depth, CTDs (conductivity, temperature depth sensors), current meters (e.g. ADCP, acoustic Doppler current profilers or deprecated rotor current meters), and biological sensors to measure various parameters. Long-term moorings can be deployed for durations of two years or more, powered with Alkaline battery, alkaline or Lithium batt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mooring Hg
A mooring is any permanent structure to which a seaborne vessel (such as a boat, ship, or amphibious aircraft) may be secured. Examples include quays, wharfs, Jetty, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An ''anchor mooring'' fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, ''mooring'' refers to the act of attaching a vessel to a mooring. The term likely stems from the Dutch language, Dutch verb ''meren'' (to ''moor''), used in English since the end of the 15th century. Permanent anchor mooring These moorings are used instead of temporary anchors because they have considerably more holding power. They cause lesser damage to the marine environment, and are convenient. Where there is a row of moorings they are termed a tier. They are also occasionally used to hold floating docks in place. There are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium Communications
Iridium Communications Inc. (formerly Iridium Satellite LLC) is a publicly traded American company headquartered in McLean, Virginia, United States. Iridium operates the Iridium satellite constellation, a system of 80 satellites: 66 are active satellites and the remaining fourteen function as in-orbit spares. Iridium Satellites are used for worldwide voice and data communication from handheld satellite phones, satellite messenger communication devices and integrated transceivers, as well as for two-way satellite messaging service from supported conventional mobile phones. The nearly polar orbit and communication between satellites via inter-satellite links provide global service availability. History The Iridium communications service was launched on November 1, 1998, formerly known as Iridium SSC. The first Iridium call was made from Vice President of the United States Al Gore to Gilbert Grosvenor, the great-grandson of Alexander Graham Bell and chairman of the Nationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanography
Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of topics, including ocean currents, waves, and geophysical fluid dynamics; fluxes of various chemical substances and physical properties within the ocean and across its boundaries; ecosystem dynamics; and plate tectonics and seabed geology. Oceanographers draw upon a wide range of disciplines to deepen their understanding of the world’s oceans, incorporating insights from astronomy, biology, chemistry, geography, geology, hydrology, meteorology and physics. History Early history Humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observations on tides were recorded by Aristotle and Strabo in 384–322 BC. Early exploration of the oceans was primarily for cartography and mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic Lander
A benthic lander is an autonomous observational platform that sits on the seabed or benthic zone to record physical, chemical or biological activity. Benthic landers have deployment durations from a few days (for biological studies) to several years (for physical oceanography studies). In these studies they conduct a variety of underwater measurements, and thus different lander configurations exist to meet differing needs for different measurements. Purpose Samples that are brought up from the seabed undergo large changes in temperature and pressure, thus changing their physical and chemical composition and properties. This change in properties means that any measurements taken from samples brought to the surface do not provide accurate data. In order to avoid this, it is best that the measurements are taken directly at the seabed level, without moving the samples. Initially, to prevent altering samples, divers would go to the sea bed and carry out the experiments. However ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of a second, where the second is defined by a hyperfine transition frequency of caesium. The metre was originally defined in 1791 by the French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's polar circumference is approximately . In 1799, the metre was redefined in terms of a prototype metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Per Second
The metre per second is the unit of both speed (a scalar (physics), scalar quantity) and velocity (a Vector (mathematics and physics), vector quantity, which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a time of one second. According to the definition of metre, is exactly \frac of the speed of light. The International System of Units, SI unit symbols are m/s, m·s−1, m s−1, or . Conversions is equivalent to: : = 3.6 kilometres per hour, km/h (exactly) : ≈ 3.2808 feet per second (approximately) : ≈ 2.2369 miles per hour (approximately) : ≈ 1.9438 knot (unit), knots (approximately) 1 feet per second, foot per second = (exactly) 1 miles per hour, mile per hour = (exactly) 1 kilometres per hour, km/h = (exactly) Relation to other measures The benz, named in honour of Karl Benz, has been proposed as a name for one metre per second. Although it has seen some suppor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind
Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hours, to global winds resulting from the difference in absorption (electromagnetic radiation), absorption of solar energy between the climate zones on Earth. The study of wind is called anemology. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect). Within the tropics and subtropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds; in areas that have variable terrain, mountain and valley breezes can prevail. Winds are commonly classified by their scale (spatial), spatial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Current
An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents move both horizontally, on scales that can span entire oceans, as well as vertically, with vertical currents (upwelling and downwelling) playing an important role in the movement of nutrients and gases, such as carbon dioxide, between the surface and the deep ocean. Ocean currents flow for great distances and together they create the global conveyor belt, which plays a dominant role in determining the climate of many of Earth's regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catenary
In physics and geometry, a catenary ( , ) is the curve that an idealized hanging chain or wire rope, cable assumes under its own weight when supported only at its ends in a uniform gravitational field. The catenary curve has a U-like shape, superficially similar in appearance to a parabola, which it is not. The curve appears in the design of certain types of Catenary arch, arches and as a cross section of the catenoid—the shape assumed by a soap film bounded by two parallel circular rings. The catenary is also called the alysoid, chainette,#MathWorld, MathWorld or, particularly in the materials sciences, an example of a funicular curve, funicular. Rope statics describes catenaries in a classic statics problem involving a hanging rope. Mathematically, the catenary curve is the Graph of a function, graph of the hyperbolic cosine function. The surface of revolution of the catenary curve, the catenoid, is a minimal surface, specifically a minimal surface of revolution. A ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite
A kite is a tethered heavier than air flight, heavier-than-air craft with wing surfaces that react against the air to create Lift (force), lift and Drag (physics), drag forces. A kite consists of wings, tethers and anchors. Kites often have a bridle and tail to guide the face of the kite so the wind can lift it. Some kite designs do not need a bridle; box kites can have a single attachment point. A kite may have fixed or moving anchors that can balance the kite. The name is derived from the kite (bird), kite, the hovering bird of prey. There are several shapes of kites. The Lift (force), lift that sustains the kite in flight is generated when air moves around the kite's surface, producing low pressure above and high pressure below the wings. The interaction with the wind also generates horizontal Drag (physics), drag along the direction of the wind. The resultant force vector from the lift and drag force components is opposed by the tension of one or more of the rope, lines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Power
Wave power is the capture of energy of wind waves to do useful mechanical work, work – for example, electricity generation, desalination, or pumping water. A machine that exploits wave power (physics), power is a wave energy converter (WEC). Waves are generated primarily by wind passing over the sea's surface and also by tidal forces, temperature variations, and other factors. As long as the waves propagate slower than the wind speed just above, energy is transferred from the wind to the waves. Air pressure differences between the windward and leeward sides of a wave crest (physics), crest and surface friction from the wind cause shear stress and wave growth. Wave power as a descriptive term is different from tidal power, which seeks to primarily capture the energy of the current caused by the gravitational pull of the Sun and Moon. However, wave power and tidal power are not fundamentally distinct and have significant cross-over in technology and implementation. Other forces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete Masonry Unit
A concrete block, also known as a cinder block in North American English, breeze block in British English, or concrete masonry unit (CMU), or by various other terms, is a standard-size rectangular block used in building construction. The use of blockwork allows structures to be built in the traditional masonry style with layers (or courses) of staggered blocks. Concrete blocks may be produced with hollow centers (cores) to reduce weight, improve insulation and provide an interconnected void into which concrete can be poured to solidify the entire wall after it is built. Concrete blocks are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them. Naming Those that use cinders (fly ash or bottom ash) as an aggregate material are called ''cinder blocks'' in the United States. They are also known as ''breeze blocks'', a term derived from ''breeze'', referring to the small cinders and cinder-dust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
