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Ceilometer
A ceilometer is a device that uses a laser or other light source to determine the height of a cloud ceiling or cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere. A ceilometer that uses laser light is a type of atmospheric lidar (light detection and ranging) instrument. Optical drum ceilometer An optical drum ceilometer uses triangulation to determine the height of a spot of light projected onto the base of the cloud. It consists essentially of a rotating projector, a detector, and a recorder. The projector emits an intense beam of light above into the sky at an angle that varies with the rotation. The detector, which is located at a fixed distance from the projector, uses a photodetector pointing vertically. When it detects the projected light return from the cloud base, the instrument notes the angle and the calculation gives the height of clouds. Laser ceilometer A laser ceilometer consists of a vertically pointing laser and a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automated Airport Weather Station
Airport weather stations are automated sensor suites which are designed to serve aviation and meteorological operations, weather forecasting and climatology. Automated airport weather stations have become part of the backbone of weather observing in the United States and Canada and are becoming increasingly more prevalent worldwide due to their efficiency and cost-savings. System types within the United States In the United States, there are several varieties of automated weather stations that have somewhat subtle but important differences. These include the automated weather observing system (AWOS) and the automated surface observing system (ASOS). Automated weather observing system (AWOS) The automated weather observing system (AWOS) units are mostly operated, maintained and controlled by state or local governments and other non-federal entities and are certified under the FAA non-federal AWOS Program. The FAA completed an upgrade of the 230 FAA owned AWOS and former automat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorological Instrumentation And Equipment
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not begin until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics, and more particularly in the latter half of the 20th century the development of the computer (allowing for the automated solution of a great many modelling equations) that significant breakthroughs in weather forecasting were achieved. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Meteorological phen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Base
A cloud base (or the base of the cloud) is the lowest altitude of the visible portion of a cloud. It is traditionally expressed either in metres or feet above mean sea level or above a planetary surface, or as the pressure level corresponding to this altitude in hectopascals (hPa, equivalent to the millibar). Measurement The height of the cloud base can be measured using a ceilometer. This device reflects a beam of light off the cloud base and then calculates its distance using either triangulation or travel time. Alternatively, the cloud base can be estimated from surface measurements of air temperature and humidity by calculating the lifted condensation level. One method for doing this, used by the U.S. Federal Aviation Administration and often named after Tom Bradbury, is as follows: #Find the difference between the surface temperature and the dew point. This value is known as the "spread". #Divide the spread by 4.4 (if temperatures are in °F) or 2.5 (if temperatures are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Lens Ceilometer
Single may refer to: Arts, entertainment, and media * Single (music), a song release Songs * "Single" (Natasha Bedingfield song), 2004 * "Single" (New Kids on the Block and Ne-Yo song), 2008 * "Single" (William Wei song), 2016 * "Single", by Meghan Trainor from the album '' Only 17'' Sports * Single (baseball), the most common type of base hit * Single (cricket), point in cricket * Single (football), Canadian football point * Single-speed bicycle Transportation * Single-cylinder engine, an internal combustion engine design with one cylinder, or a motorcycle using such engine * Single (locomotive), a steam locomotive with a single pair of driving wheels * As a verb: to convert a double-track railway to a single-track railway Other uses * Single (mathematics) (1-tuple), a list or sequence with only one element * Single person, a person who is not in a committed relationship * Single precision, a computer numbering format that occupies one storage location in computer memory at ... [...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 the noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR, bandwidth, and channel capacity of a communication channel are connected by the Shannon–Hartley theorem. Definition Signal-to-noise ratio is defined as the ratio of the power of a signal (meaningful input) to the power of background noise (meaningless or unwanted input): : \mathrm = \frac, where is average power. Both signal and noise power must be measured at the same or equivalent points in a system, and within the same system bandwidth. Depending on whether the signal is a constant () or a random variable (), the signal-to-noise ratio for random noise becomes: : \mathrm = \frac where E refers to the expected value, i.e. in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGill University
McGill University (french: link=no, Université McGill) is an English-language public research university located in Montreal, Quebec Montreal ( ; officially Montréal, ) is the second-most populous city in Canada and most populous city in the Canadian province of Quebec. Founded in 1642 as '' Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple-pe ..., Canada. Founded in 1821 by royal charter granted by George IV, King George IV,Frost, Stanley Brice. ''McGill University, Vol. I. For the Advancement of Learning, 1801–1895.'' McGill-Queen's University Press, 1980. the university bears the name of James McGill, a Scottish merchant whose bequest in 1813 formed the university's precursor, University of McGill College (or simply, McGill College); the name was officially changed to McGill University in 1885. McGill's main campus is on the slope of Mount Royal in downtown Montreal in the borough of Ville-Marie, Montreal, Ville-Marie, with a Macdona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robins Air Force Base
Robins Air Force Base is a major United States Air Force installation located in Houston County, Georgia, United States. The base is located just east of the city of Warner Robins, south-southeast of Macon and approximately south-southeast of Atlanta, Georgia. The base is named in honor of Brig Gen Augustine Warner Robins, the Air Force's "father of logistics". Robins AFB is the home of the Air Force Materiel Command's Warner Robins Air Logistics Complex (WR-ALC) (FLZ) which is the worldwide manager for a wide range of aircraft, engines, missiles, software and avionics and accessories components. The commander of WR-ALC is Brigadier General Jennifer Hammerstedt. It is one of three Air Force Air Logistic Complexes, the others being Oklahoma City Air Logistics Complex (OC-ALC) at Tinker Air Force Base, Oklahoma, and Ogden Air Logistics Complex (OO-ALC) at Hill Air Force Base, Utah. The host unit at Robins AFB is the 78th Air Base Wing (78 ABW) which provides services and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Areal Extent
Areal can refer to: * An adjective pertaining to an area * Areal, Rio de Janeiro, a municipality in Brazil * António Areal (1934—1978), Portuguese painter * Sofia Areal (born 1960), Portuguese painter, António Areal's daughter See also * Area (other) * Areal density (computer storage) * Areal feature In geolinguistics, areal features are elements shared by languages or dialects in a geographic area, particularly when such features are not descended from a proto-language, or, common ancestor language. That is, an areal feature is contrasted to ... in linguistics * Areal velocity, a term from classical mechanics * Areal, a scrapped video game {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its surrounding areas) is home to over 65% of the population. Iceland is the biggest part of the Mid-Atlantic Ridge that rises above sea level, and its central volcanic plateau is erupting almost constantly. The interior consists of a plateau characterised by sand and lava fields, mountains, and glaciers, and many glacial rivers flow to the sea through the lowlands. Iceland is warmed by the Gulf Stream and has a temperate climate, despite a high latitude just outside the Arctic Circle. Its high latitude and marine influence keep summers chilly, and most of its islands have a polar climate. According to the ancient manuscript , the settlement of Iceland began in 874 AD when the Norwegian chieftain Ingólfr Arnarson became the first p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants have an anthropogenic source – that is, a source created by human activities. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed nine million people worldwide (one in six deaths). This remained unchanged in 2019, with little real progress against pollution being identifiable. Air pollution accounted for of these earlier deaths. Major forms of pollution include air pollution, light pollution, litter, noise pollution, plastic pollution, soil contamination, radioac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lidar
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light. It has terrestrial, airborne, and mobile applications. ''Lidar'' is an acronym of "light detection and ranging" or "laser imaging, detection, and ranging". It is sometimes called 3-D laser scanning, a special combination of 3-D scanning and laser scanning. Lidar is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swath mapping (ALSM), and laser altimetry. It is also used in control and navigation for som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
