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Sea State
In oceanography, sea state is the general condition of the free surface on a large body of water—with respect to wind waves and swell—at a certain location and moment. A sea state is characterized by statistics, including the wave height, period, and spectrum. The sea state varies with time, as the wind and swell conditions change. The sea state can be assessed either by an experienced observer (like a trained mariner) or by using instruments like weather buoys, wave radar or remote sensing satellites. In the case of buoy measurements, the statistics are determined for a time interval in which the sea state can be considered to be constant. This duration has to be much longer than the individual wave period, but shorter than the period in which the wind and swell conditions can be expected to vary significantly. Typically, records of one hundred to one thousand wave periods are used to determine the wave statistics. The large number of variables involved in creating and des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wea00810
The Wea were a Miami-Illinois-speaking Native American tribe originally located in western Indiana. Historically, they were described as either being closely related to the Miami Tribe or a sub-tribe of Miami. Today, the descendants of the Wea, along with the Kaskaskia, Piankeshaw, and Peoria, are enrolled in the Peoria Tribe of Indians of Oklahoma, a federally recognized tribe in Oklahoma. Name The name ''Wea'' is used today as the a shortened version of their numerous recorded names. The Wea name for themselves (autonym) in their own language is ''waayaahtanwa'', derived from ''waayaahtanonki'', 'place of the whirlpool', where they were first recorded being seen and where they were living at that time. The many different spellings of the tribe's name include Waiatanwa, Ouaouiatanoukak, Aoiatenon, Aouciatenons, Ochiatenens, Ouatanons, Ouias, Ouiatanon, Wah-we-ah-tung-ong, Warraghtinooks, and Wyatanons. Language The Wea spoke a dialect of Miami-Illinois language, part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called Transponder (satellite communications), transponders. Many satellites use a Satellite bus, standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming Satellite constellation, constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio Broadcast relay station, relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanography
Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an 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 utilize to glean further knowledge of the world ocean, including 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. History Early history Humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowditch's American Practical Navigator
''The American Practical Navigator'' (colloquially often referred to as ''Bowditch''), originally written by Nathaniel Bowditch, is an encyclopedia of navigation. It serves as a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary. In 1867 the copyright and plates were bought by the Hydrographic Office of the United States Navy. As of 2019 it is still published by the U.S. Government and is available free online from the National Geospatial-Intelligence Agency (NGA), the modern successor agency to the 19th Century Hydrographic Office. The publication is considered one of America's nautical institutions. History The most popular navigational text of the late 18th century was ''The Practical Navigator'' by John Hamilton Moore of the Royal Navy, first published in 1772. To have exact tables to work from, Bowditch recomputed all of Moore's tables, and rearranged and expanded the work. He contacted the US publisher of the work, Edmu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Sea
A cross sea (also referred to as a squared sea or square waves) is a sea state of wind-generated ocean waves that form nonparallel wave systems. Cross seas have a large amount of directional spreading. This may occur when water waves from one weather system continue despite a shift in wind Wind is the natural movement of air or other gases relative to a 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 ho .... Waves generated by the new wind run at an angle to the old. Two weather systems that are far from each other may create a cross sea when the waves from the systems meet at a place far from either weather system. Until the older waves have dissipated, they can present a perilous sea hazard. This sea state is fairly common and a large percentage of ship accidents have been found to occur in this state. Vessels fare better against large waves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaufort Scale
The Beaufort scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort wind force scale. History The scale was devised in 1805 by the Irish hydrographer Francis Beaufort (later Rear Admiral), a Royal Navy officer, while serving on . The scale that carries Beaufort's name had a long and complex evolution from the previous work of others (including Daniel Defoe the century before) to when Beaufort was Hydrographer of the Navy in the 1830s, when it was adopted officially and first used during the voyage of HMS ''Beagle'' under Captain Robert FitzRoy, who was later to set up the first Meteorological Office (Met Office) in Britain giving regular weather forecasts. In the 18th century, naval officers made regular weather observations, but there was no standard scale and so they could be very subjective – one man's "stiff breeze" might be another's "soft breeze". Beaufort succeeded in standardising the sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Response Amplitude Operator
In the field of ship design and design of other floating structures, a response amplitude operator (RAO) is an engineering statistic, or set of such statistics, that are used to determine the likely behavior of a ship when operating at sea. Known by the acronym of ''RAO'', response amplitude operators are usually obtained from models of proposed ship designs tested in a model basin, or from running specialized CFD computer programs, often both. RAOs are usually calculated for all ship motions and for all wave headings. Usage RAOs are effectively transfer functions used to determine the effect that a sea state will have upon the motion of a ship through the water, and therefore, for example, whether or not (in the case of cargo vessels) the addition of cargo to the vessel will require measures to be taken to improve stability and prevent the cargo from shifting within the vessel. Generation of extensive RAOs at the design phase allows shipbuilders to determine the modifications t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Period
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Height
In fluid dynamics, the wave height of a surface wave is the difference between the elevations of a crest and a neighboring trough. ''Wave height'' is a term used by mariners, as well as in coastal, ocean and naval engineering. At sea, the term ''significant wave height'' is used as a means to introduce a well-defined and standardized statistic to denote the characteristic height of the random waves in a ''sea state'', including wind sea and swell. It is defined in such a way that it more or less corresponds to what a mariner observes when estimating visually the average wave height. Definitions Depending on context, wave height may be defined in different ways: *For a sine wave, the wave height ''H'' is twice the amplitude (i.e., the '' peak-to-peak amplitude''): H = 2a. *For a periodic wave, it is simply the difference between the maximum and minimum of the surface elevation : H = \max\left\ - \min\left\, with ''c''p the phase speed (or propagation speed) of the wave. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wasser über Deck Und Luken WNA
Wasser means " Water" in German. It may refer to: People * Anna Waser (1678–1714), Swiss painter * Annemarie Waser (born 1940), Swiss alpine skier * Ed Wasser (born 1964), actor * Edgar Wasser (born 1990), German musician * Joan Wasser, musician * Laura Wasser (born 1968), attorney * Markus Wasser (born 1968), bobsledder * Thierry Wasser, contemporary perfumer Places * Wasser, Germany, a village Other uses * Wasser- und Schifffahrtsamt, a regional German agency responsible for the administration of federal navigable waters * Wasser- und Zugvogelreservate, several bird reserves in Switzerland * ''Wasser im Wind'', album by keyboardist Hans-Joachim Roedelius See also * Vasser * Waser * Wassermann (other) Wasserman or Wassermann is a surname. Notable people with the surname include: * Aaron E. Wasserman (1920–2015), American food scientist * Aharon Wasserman (born 1986), American entrepreneur and software designer * Al Wasserman (born 1921), Am ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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