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Sondrestrom Upper Atmospheric Research Facility
The Sondrestrom Upper Atmospheric Research Facility was an ionospheric and atmospheric research facility situated about west of Kangerlussuaq, Greenland. It was commonly known around the town as Kellyville. The facility was operational from 1983 to 2018. The ionospheric radar was first constructed by SRI International at Stanford, California, then moved to Chatanika, Alaska, where it was operational from November 1971 to March 1982. It was transported to Kangerlussuaq in 1983. It was operated by SRI International for the U.S. National Science Foundation and the Danish Meteorological Institute. This facility hosted more than 20 instruments, the majority of which provided unique and complementary information about the arctic upper atmosphere. The centerpiece instrument of the facility was an L band incoherent scatter Incoherent scattering is a type of scattering phenomenon in physics. The term is most commonly used when referring to the scattering of an electromagnetic wave (usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude. Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kangerlussuaq
Kangerlussuaq (; ; da, Søndre Strømfjord), is a settlement in western Greenland in the Qeqqata municipality located at the head of the fjord of the same name. It is Greenland's main air transport hub and the site of Greenland's largest commercial airport. The airport dates from American settlement during and after World War II, when the site was known as Bluie West-8 and then Sondrestrom Air Base. The Kangerlussuaq area is also home to Greenland's most diverse terrestrial fauna, including muskoxen, caribou, and gyrfalcons. The settlement's economy and population of 508 is almost entirely reliant on the airport and tourist industry. Geography Kangerlussuaq occupies an alluvial flatland on the far end of the 190 km long Kangerlussuaq Fjord, straddling both sides of the Qinnguata Kuussua river estuary. East of Kangerlussuaq there is a confluence of the two major regional rivers, the Qinnguata Kuussua and Akuliarusiarsuup Kuua. The valley of the latter forms large quicksa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is the world's largest island. It is one of three constituent countries that form the Kingdom of Denmark, along with Denmark and the Faroe Islands; the citizens of these countries are all citizens of Denmark and the European Union. Greenland's capital is Nuuk. Though a part of the continent of North America, Greenland has been politically and culturally associated with Europe (specifically Norway and Denmark, the colonial powers) for more than a millennium, beginning in 986.The Fate of Greenland's Vikings , by Dale Mackenzie Brown, ''Archaeological Institute of America'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SRI International
SRI International (SRI) is an American nonprofit scientific research institute and organization headquartered in Menlo Park, California. The trustees of Stanford University established SRI in 1946 as a center of innovation to support economic development in the region. The organization was founded as the Stanford Research Institute. SRI formally separated from Stanford University in 1970 and became known as SRI International in 1977. SRI performs client-sponsored research and development for government agencies, commercial businesses, and private foundations. It also licenses its technologies, forms strategic partnerships, sells products, and creates spin-off companies. SRI's headquarters are located near the Stanford University campus. SRI's annual revenue in 2014 was approximately $540 million, which tripled from 1998 under the leadership of Curtis Carlson. In 1998, the organization was on the verge of bankruptcy when Carlson took over as CEO. Over the next sixteen years wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chatanika, Alaska
Chatanika is a small unincorporated community located in the Fairbanks North Star Borough, Alaska, United States, north-northeast of the city of Fairbanks. The community runs along an approximately stretch of the Steese Highway, the majority of which sees the highway paralleled by the Chatanika River. The community consists of sparsely scattered residential subdivisions, several roadside businesses, a boat launch where the Steese Highway crosses the Chatanika River, relics of past gold mining operations in the area and the Poker Flat Research Range operated by the Geophysical Institute of the University of Alaska Fairbanks. Chatanika was one of over a dozen small communities in the vicinity of Fairbanks whose prosperity was tied to gold mining during the Fairbanks Gold Rush. Chatanika, as the northern terminus of the narrow-gauge Tanana Valley Railroad, also owed much of its early prosperity to railroad operations, which were closely tied to the mining activity. Chat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health. With an annual budget of about $8.3 billion (fiscal year 2020), the NSF funds approximately 25% of all federally supported basic research conducted by the United States' colleges and universities. In some fields, such as mathematics, computer science, economics, and the social sciences, the NSF is the major source of federal backing. The NSF's director and deputy director are appointed by the President of the United States and confirmed by the United States Senate, whereas the 24 president-appointed members of the National Science Board (NSB) do not require Senate confirmation. The director and deputy director are responsible for administration, planning, budgeting and day-to-day operations of the foundation, while t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danish Meteorological Institute
The Danish Meteorological Institute (DMI; da, Danmarks Meteorologiske Institut) is the official Danish meteorological institute, administrated by the Ministry of Energy, Utilities and Climate. The institute makes weather forecasts and observations for Denmark, Greenland, and the Faroe Islands. History It was founded in 1873, largely through the efforts of Ludwig A. Colding. The Danish Meteorological Institute – DMI – encompasses the combined knowledge of the former Meteorological Institute, the Meteorological Service for Civil Aviation and the Meteorological Service for Defence. The Meteorological Institute was founded in 1872 under the Ministry of the Navy. The Meteorological Service for Civil Aviation was established in 1926, and used to be part of the Civil Aviation Administration. The Meteorological Service for Defence was established in 1953. The present-day DMI was established in 1990 through the merger of the three above-mentioned institutions. DMI is organized unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic
The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), Finland, Iceland, Norway, Russia (Murmansk Oblast, Murmansk, Siberia, Nenets Autonomous Okrug, Nenets Okrug, Novaya Zemlya), Sweden and the United States (Alaska). Land within the Arctic region has seasonally varying snow and sea ice, ice cover, with predominantly treeless permafrost (permanently frozen underground ice) containing tundra. Arctic seas contain seasonal sea ice in many places. The Arctic region is a unique area among Earth's ecosystems. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. Life in the Arctic includes zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants and human societies. Arctic land is bordered by the subarctic. De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L Band
The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz). This is at the top end of the ultra high frequency (UHF) band, at the lower end of the microwave range. Applications Mobile service In Europe, the Electronic Communications Committee (ECC) of the European Conference of Postal and Telecommunications Administrations (CEPT) has harmonized part of the L band (1452–1492 MHz), allowing individual countries to adopt this spectrum for terrestrial mobile/fixed communications networks supplemental downlink (MFCN SDL). By means of carrier aggregation, an LTE-Advanced or UMTS/HSDPA base station could use this spectrum to provide additional bandwidth for communications from the base station to the mobile device; i.e., in the downlink direction. In the Americas, mobile services are operated between the 1.7 GHz to 2.1 GHz range in the PCS and AWS bands. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incoherent Scatter
Incoherent scattering is a type of scattering phenomenon in physics. The term is most commonly used when referring to the scattering of an electromagnetic wave (usually light or radio frequency) by random fluctuations in a gas of particles (most often electrons). The most well known practical application is known as incoherent scatter radar theory, a ground-based technique for studying the Earth's ionosphere first proposed by Professor William E. Gordon in 1958. A radar beam scattering off electrons in the ionospheric plasma creates an incoherent scatter return. When an electromagnetic wave is transmitted through the atmosphere, each of the electrons in the ionospheric plasma essentially acts as an antenna excited by the incoming wave, and the wave is re-radiated from the electron. Since the electrons are all moving at varying speeds as a result of ionospheric dynamics and random thermal motion, the reflection from each electron is also Doppler shifted. The receiver on the gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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