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Sound Channel Axis
The SOFAR channel (short for sound fixing and ranging channel), or deep sound channel (DSC), is a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum. The SOFAR channel acts as a waveguide for sound, and low frequency sound waves within the channel may travel thousands of miles before dissipating. An example was reception of coded signals generated by the US Navy-chartered ocean surveillance vessel ''Cory Chouest'' off Heard Island, located in the southern Indian Ocean (between Africa, Australia and Antarctica), by hydrophones in portions of all five major ocean basins and as distant as the North Atlantic and North Pacific.Figure 1 of the referenc"The Heard Island Feasibility Test"(Munk) shows ray paths to receiving locations. Table 1 lists the sites with one being a Canadian research vessel with a towed array off Cape Cod. This phenomenon is an important factor in ocean surveillance. The deep sound channel was discovered and described indep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Speed Of Sound
An underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature (called a Water, body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation. Liquid water has been present on Earth for most of the History of Earth, history of the planet. The underwater environment is thought to be the place of the origin of life on Earth, and it remains the ecological region most critical to the support of life and the natural habitat of the majority of living organisms. Several branches of science are dedicated to the study of this environment or specific parts or aspects of it. A number of human activities are conducted in the more accessible parts of the underwater environment. These include research, underwater diving for work or recreation, and underwater warfare with submarines. It is hostile to humans in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rays Test
Ray or RAY may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), the bony or horny spine on ray-finned fish Science and mathematics * Half-line (geometry) or ray, half of a line split at an initial point * Directed half-line or ray, half of a directed or oriented line split at an initial point * Ray (graph theory), an infinite sequence of vertices such that each vertex appears at most once in the sequence and each two consecutive vertices in the sequence are the two endpoints of an edge in the graph * Ray (optics), an idealized narrow beam of light * Ray (quantum theory), an equivalence class of state-vectors representing the same state Arts and entertainment Music * The Rays, an American musical group active in the 1950s * Ray (musician), stage name of Japanese singer Reika Nakayama (born 1990) * Ray (girl group), a Japanese girl group formed in 2019 * Ray J, stage name of singer William Ray Norwood, Jr. (born 1981) * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SOFAR Bomb
In oceanography, a sofar bomb (Sound Fixing And Ranging bomb), occasionally referred to as a sofar disc, is a long-range position-fixing system that uses impulsive sounds in the deep sound channel ( SOFAR channel) of the ocean to enable pinpointing of the location of ships or crashed planes. The deep sound channel is ideal for the device, as the minimum speed of sound at that depth improves the signal's traveling ability. A position is determined from the differences in arrival times at receiving stations of known geographic locations. The useful range from the signal sources to the receiver can exceed . Design For this device to work as intended, it must have several qualities. Firstly, the bomb needs to detonate at the correct depth, so that it can take full advantage of the deep sound channel. The sofar bomb has to sink fast enough so that it reaches the required depth within a reasonable amount of time (usually about 5 minutes). To determine the position of a sofar bomb that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Convergence
The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. The line separates the clockwise Antarctic circumpolar current from other oceans. Antarctic waters predominantly sink beneath the warmer subantarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill. This line, like the Arctic tree line, is a natural boundary rather than an artificial one, such as the borders of nations and time zones. It not only separates two hydrological regions, but also separates areas of distinctive marine life and climates. The Arctic has no similar boundary because of the large bodies of land contiguous with the northern polar region. History The Antarctic Convergence was first crossed by Anthony de la Roché in 1675 and Edmond Halley i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bermuda
Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest. Bermuda is an archipelago consisting of List of islands of Bermuda, 181 islands, although the most significant islands are connected by bridges and appear to form one landmass. It has a land area of . Bermuda has a tropical climate, with warm winters and hot summers. Its climate also exhibits Oceanic climate, oceanic features similar to other coastal areas in the Northern Hemisphere with warm, moist air from the ocean ensuring relatively high humidity and stabilising temperatures. Bermuda is prone to severe weather from Westerlies#Interaction with tropical cyclones, recurving tropical cyclones; however, it receives some protection from a coral reef and its position north of the Main Development Region, which limits the direction and severity of approach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perth, Australia
Perth () is the capital city of Western Australia. It is the fourth-most-populous city in Australia, with a population of over 2.3 million within Greater Perth . The world's most isolated major city by certain criteria, Perth is part of the South West Land Division of Western Australia, with most of Perth's metropolitan area on the Swan Coastal Plain between the Indian Ocean and the Darling Scarp. The city has expanded outward from the original British settlements on the Swan River, upon which its central business district and port of Fremantle are situated. Perth was founded by Captain James Stirling in 1829 as the administrative centre of the Swan River Colony. The city is situated on the traditional lands of the Whadjuk Noongar people, where Aboriginal Australians have lived for at least 48,000 years. Perth was named after the city of Perth in Scotland. Initially established as a free settlement, the colony accepted transported convicts from 1850 to supply labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PARKA I Track Acoustic Enfironment - Kaneohe-Alaska SOFAR Channel
A parka, like the related anorak, is a type of coat with a hood, that may be lined with fur or fake fur. Parkas and anoraks are staples of Inuit clothing, traditionally made from caribou or seal skin, for hunting and kayaking in the frigid Arctic. Some Inuit anoraks require regular coating with fish oil to retain their water resistance. Parkas are typically longer, often extending to the thighs or knees. Anoraks are usually shorter than parkas, often hip-length, and are traditionally a pull-over jacket. The words ''anorak'' and ''parka'' have been used interchangeably, but they are somewhat different garments. Strictly speaking, an anorak is a waterproof, hooded, pull-over jacket without a front opening, and sometimes drawstrings at the waist and cuffs, and a parka is a hip-length cold-weather coat, typically stuffed with down or very warm synthetic fiber, and with a fur-lined hood. Etymology The word ''anorak'' comes from the Greenlandic (''Kalaallisut'') word ''annoraaq' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal-to-noise Ratio
Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR is an important parameter that affects the performance and quality of systems that process or transmit signals, such as communication systems, audio systems, radar systems, imaging systems, and data acquisition systems. A high SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover. SNR can be improved by various methods, such as increasing the signal strength, reducing the noise level, filtering out unwanted noise, or using error correction techniques. SNR also determines the maximum possible amount of data that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missile Impact Locating System
The Missile Impact Location System or Missile Impact Locating System (MILS)Both full names are found in references. is an ocean Underwater acoustic positioning system, acoustic detection system designed to locate the impact position of test missile nose cones at the ocean's surface and then the position of the cone itself for recovery from the ocean bottom. The systems were installed in the missile test ranges managed by the U.S. Air Force. The systems were first installed in the Eastern Range, at the time the Atlantic Missile Range, and secondly in the Pacific, then known as the Western Range (USSF), Pacific Missile Range. The Atlantic Missile Impact Location System and Pacific Missile Impact Location System were installed from 1958 through 1960. Design and development was by American Telephone and Telegraph Company (AT&T), with its Bell Laboratories research and Western Electric manufacturing elements and was to an extent based on the company's technology and experience developin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
