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Low-level Windshear Alert System
A low-level windshear alert system (LLWAS) measures average surface wind speed and direction using a network of remote sensor stations, situated near runways and along approach or departure corridors at an airport. Wind shear is the generic term for wind differences over an operationally short distance (in relation to flight) which encompass meteorological phenomena including gust fronts, microbursts, vertical shear, and derechos. Background LLWAS compares results over its operating area to determine whether calm, steady winds, wind shifts (in relation to runways), wind gusts, divergent winds, sustained divergent winds (indicative of shear), or strong and sustained divergent winds (indicative of microbursts) are observed. A LLWAS master station polls each remote station every system cycle (nominally every ten seconds) and provides prevailing airport wind averages, runway specific winds, gusts, may set new wind shear alerts or microburst alerts and reset countdown timers of elapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LLWAS
A low-level windshear alert system (LLWAS) measures average surface wind speed and direction using a network of remote sensor stations, situated near runways and along approach or departure corridors at an airport. Wind shear is the generic term for wind differences over an operationally short distance (in relation to flight) which encompass meteorological phenomena including gust fronts, microbursts, vertical shear, and derechos. Background LLWAS compares results over its operating area to determine whether calm, steady winds, wind shifts (in relation to runways), wind gusts, divergent winds, sustained divergent winds (indicative of shear), or strong and sustained divergent winds (indicative of microbursts) are observed. A LLWAS master station polls each remote station every system cycle (nominally every ten seconds) and provides prevailing airport wind averages, runway specific winds, gusts, may set new wind shear alerts or microburst alerts and reset countdown timers of elapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Aviation Administration
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic management, certification of personnel and aircraft, setting standards for airports, and protection of U.S. assets during the launch or re-entry of commercial space vehicles. Powers over neighboring international waters were delegated to the FAA by authority of the International Civil Aviation Organization. Created in , the FAA replaced the former Civil Aeronautics Administration (CAA) and later became an agency within the U.S. Department of Transportation. Major functions The FAA's roles include: *Regulating U.S. commercial space transportation *Regulating air navigation facilities' geometric and flight inspection standards *Encouraging and developing civil aeronautics, including new aviation technology *Issuing, suspending, or revoki ... [...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] |
NEXRAD
NEXRAD or Nexrad (Next-Generation Radar) is a network of 160 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce, the Federal Aviation Administration (FAA) within the Department of Transportation, and the U.S. Air Force within the Department of Defense. Its technical name is WSR-88D (''Weather Surveillance Radar, 1988, Doppler''). NEXRAD detects precipitation and atmospheric movement or wind. It returns data which when processed can be displayed in a mosaic map which shows patterns of precipitation and its movement. The radar system operates in two basic modes, selectable by the operator – a slow-scanning ''clear-air mode'' for analyzing air movements when there is little or no activity in the area, and a ''precipitation mode'', with a faster scan for tracking active weather. NEXRAD has an increased emphasis on automa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Weather Service Unit
A Center Weather Service Unit (CWSU) is a National Weather Service (NWS) unit located inside each of the Federal Aviation Administration's 22 Air Route Traffic Control Centers (ARTCC). Overview CWSU meteorologists provide support for FAA's air traffic management with pertinent meteorological information for airports and airspace in the control center's area of responsibility. Meteorologists disseminate information to brief air traffic control area managers where, when, and what is expected, when the weather arrives in the ARTCC's various sectors. Dissemination is by computer products, by incoming phone requests, and by stand up briefings. Occasionally CWSUs provide weather information and recommendations directly to air traffic controllers. They sometimes will provide information directly to the pilots of aircraft in distress due to hazardous weather conditions. In addition to SIGMETs (significant meteorological events), Convective SIGMETs (significant meteorological event a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airborne Wind Shear Detection And Alert System
The airborne wind shear detection and alert system, fitted in an aircraft, detects and alerts the pilot both visually and aurally of a wind shear condition. A reactive wind shear detection system is activated by the aircraft flying into an area with a wind shear condition of sufficient force to pose a hazard to the aircraft. A predictive wind shear detection system is activated by the presence of a wind shear condition ahead of the aircraft. In 1988, the U.S. Federal Aviation Administration (FAA) mandated that all turbine-powered commercial aircraft must have on-board wind shear detection systems by 1993. Airlines successfully lobbied to have commercial turbo-prop aircraft exempted from this requirement. In the predictive wind shear detection mode, the weather radar processor of the aircraft detects the presence of a microburst, a type of vertical wind shear condition, by detecting the Doppler frequency shift of the microwave pulses caused by the microburst ahead of the aircraft, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USAir Flight 1016
USAir Flight 1016 was a regularly scheduled flight in the southeastern United States, between Columbia, South Carolina, and Charlotte, North Carolina. On July 2, 1994, the flight encountered heavy thunderstorms and microburst-induced windshear while attempting to land, and crashed into heavy trees and a private residence near the The crash and ensuing fire caused 37 fatalities and seriously injured Flight History of the flight On Saturday, July 2, 1994, the McDonnell Douglas DC-9, registered ''N954VJ,'' that was flying as USAir Flight 1016 departed Columbia Metropolitan Airport at 18:15 EDT for the 35-minute flight to Charlotte/Douglas International Airport. The crew consisted of Captain Michael Greenlee (38), First Officer James Phillip "Phil" Hayes (41), and three flight attendants. There were 52 passengers (including two infants) on board. The flight was uneventful until the approach to Charlotte, where several severe thunderstorms were in the vicinity of the airport. At ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Transportation Safety Board
The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on aviation accidents and incidents, certain types of highway crashes, ship and marine accidents, pipeline incidents, bridge failures, and railroad accidents. The NTSB is also in charge of investigating cases of hazardous materials releases that occur during transportation. The agency is based in Washington, D.C. It has four regional offices, located in Anchorage, Alaska; Denver, Colorado; Ashburn, Virginia; and Seattle, Washington. The agency also operates a national training center at its Ashburn facility. History The origin of the NTSB was in the Air Commerce Act of 1926, which assigned the United States Department of Commerce responsibility for investigating domestic aviation accidents. Before the NTSB, the Federal Aviation Administration's (FAA; at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Doppler Weather Radar
Terminal Doppler Weather Radar (TDWR) is a Doppler weather radar system with a three-dimensional "pencil beam" used primarily for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports situated in climates with great exposure to thunderstorms in the United States. As of 2011, all were in-service with 45 operational radars, some covering multiple airports in major metropolitan locations, across the United States & Puerto Rico. Several similar weather radars have also been sold to other countries such as China (Hong Kong). Funded by the United States Federal Aviation Administration (FAA), TDWR technology was developed in the early 1990s at Lincoln Laboratory, part of the Massachusetts Institute of Technology, to assist air traffic controllers by providing real-time wind shear detection and high-resolution precipitation data. The primary advantage of TDWRs over previous weather radars is that it has a finer range resolution—me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather Radar
Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather. During World War II, radar operators discovered that weather was causing echoes on their screen, masking potential enemy targets. Techniques were developed to filter them, but scientists began to study the phenomenon. Soon after the war, surplus radars were used to detect precipitation. Since then, weather radar has evolved on its own and is now used by national weather services, research departments in universities, and in television stations' weather departments. Raw images are routinely used and specialize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ted Fujita
was a Japanese-American meteorologist whose research primarily focused on severe weather. His research at the University of Chicago on severe thunderstorms, tornadoes, hurricanes, and typhoons revolutionized the knowledge of each. Although he is best known for creating the Fujita scale of tornado intensity and damage, he also discovered downbursts and microbursts, and was an instrumental figure in advancing modern understanding of many severe weather phenomena and how they affect people and communities, especially through his work exploring the relationship between wind speed and damage. Biography Fujita was born in the village of Sone, Fukuoka Prefecture, Japan, an area that is now part of the city of Kitakyushu. He studied and taught at Kyushu Institute of Technology. In 1953 he was invited to the University of Chicago by Horace R. Byers, who had become interested in Fujita's research, particularly his independent discovery of the cold-air downdraft. Fujita remained at the Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Project NIMROD
Project NIMROD (Northern Illinois Meteorological Research On Downburst) was a meteorological field study of severe thunderstorms and their damaging winds conducted by the National Center for Atmospheric Research (NCAR). It took place in the Greater Chicago area from May 15 to June 30, 1978. Data collected was from single cell thunderstorms as well as mesoscale convective systems, such as bow echoes. Using Doppler weather radars and damage clues on the ground, the team studied mesocyclones, downbursts and gust fronts. NIMROD was the first time that microbursts, very localized strong downdrafts under thunderstorms, were detected; this helped improve airport and public safety by the development of systems like the Terminal Doppler Weather Radar and the Low-level windshear alert system. Description The project was set up by Ted Fujita and Ramesh Srivastava from the University of Chicago, with research assistants from the university Roger Wakimoto and Gregory S. Forbes helping, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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