FullDescription:Meteorology
AIRMET
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| Term | AIRMET |
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Abbreviation
Definition
information concerning en-route weather phenomena which may affect the safety of low-level aircraft operations.
Definition Source
ICAO, Official Definition, DOC 8400 Procedures for Air Navigation Services — ICAO Abbreviations and Codes 2004, 6th ed.
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AIRMET information
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| Term | AIRMET information |
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Abbreviation
Definition
Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub-area thereof.
Definition Source
ICAO, Official definition
ANNEX 3 Meteorological Service for International Air Navigation 2010
ANNEX 11 Air Traffic Services 2001
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ASHTAM
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Abbreviation
Definition
A special series NOTAM notifying by means of a specific format change in activity of a volcano, a volcanic eruption and/or volcanic ash cloud that is of significance of aircraft operations
Definition Source
ICAO/OACI, "International Civil Aviation Vocabulary", Doc. 9713, Vol.1, 1998
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Adverse weather conditions
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| Term | adverse weather conditions |
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degraded weather conditions |
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Abbreviation
Definition
Degraded weather condition: a condition which might have a significant negative impact on airport performance unless a proper response is organized (i.e. the selection of an airport operating mode to respond to given degraded conditions and eventually the use of additional airport resources such as de-icing/anti-icing services). This would be the case when visibility is poor and/or in case of freezing conditions, precipitations, etc.
Definition Source
ATM Airport Performance Framework (ATMAP) Measuring Airport Airside and Nearby Airspace Performance, December 2009
Note
Lexicon Release
Lexicon Release 2015.2
Aerodrome forecast
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| Term | aerodrome forecast |
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terminal aerodrome forecast |
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Abbreviation
TAF
Definition
A TAF is a forecast that consists of a concise statement of the expected meteorological conditions at an aerodrome for a specific time period. A TAF contains information on the expected surface wind, visibility, weather and clouds as well as on expected significant changes to one or more of these elements during the validity period.
Definition Source
BELGOCONTROL (2010) homepage, Meteorology [1]
Note
Two types of TAFs exist: the 'short' TAF (TAF FC) has a validity period of 9 hours and is issued every 3 hours while the 'long' TAF (TAF FT) has a validity period of 30 hours and is issued every 6 hours. (same source)
Aircraft observation
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| Term | aircraft observation |
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Abbreviation
Definition
The evaluation of one or more meteorological elements made from an aircraft in flight.
Definition Source
ICAO, Official definition, ANNEX 3 Meteorological Service for International Air Navigation 2010
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Aircraft turbulence
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| Term | aircraft turbulence |
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Abbreviation
Definition
Irregular motion of an aircraft in flight, especially when characterized by rapid up-and-down motion, caused by a rapid variation of atmospheric wind velocities.
Definition Source
American Meteorological Society (AMS), Glossary of Meteorology [2] 2000
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Aneroid barometer
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| Term | aneroid barometer |
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Abbreviation
Definition
An instrument for measuring atmospheric pressure.
Definition Source
American Meteorological Society, Glossary of Meteorology [3]
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Area of responsibility (world area forecast system)
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| Term | area of responsibility (world area forecast system) |
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Abbreviation
Definition
A geographical area for which a regional area forecast centre prepares significant weather forecasts.
Definition Source
ICAO, Official definition, ANNEX 3 Meteorological Service for International Air Navigation 2010
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Automated weather observation system
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| Term | automated weather observation system |
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automatic weather observation system |
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Abbreviation
AWOS
Definition
a set of meteorological sensors, and associated systems designed to electronically collect and disseminate meteorological data.
Definition Source
Transport Canada, GLOSSARY FOR PILOTS AND AIR TRAFFIC SERVICES PERSONNEL, FEBRUARY 2009 EDITION
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Barometric altitude
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| Term | barometric altitude |
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Abbreviation
Definition
Geopotential altitude in the Earth's atmosphere above mean standard sea level pressure datum plane, measured by a pressure (barometric) altimeter.
Definition Source
ICAO, doc. GNSSP/2 Rep. p. 1A-43
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Clear-air turbulence
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| Term | clear-air turbulence |
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Abbreviation
CAT
Definition
A higher altitude (6–15 km) turbulence phenomenon occurring in cloud-free regions, associated with wind shear, particularly between the core of a jet stream and the surrounding air.
Definition Source
American Meteorological Society (AMS), Glossary of Meteorology [4] 2000
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Collaborative Convective Forecast Product
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| Term | Collaborative Convective Forecast Product |
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Abbreviation
CCFP
Definition
a graphical representation of forecast convective occurrence verifying at 2-, 4 -, and 6-hours after issuance time.
Definition Source
(United States) Aviation Weather Services, Advisory Circular 00-45F, Revision 1
Note
Disruptive weather condition
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| Term | disruptive weather condition |
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Abbreviation
Definition
a condition which is very unlikely to occur, it has a severe impact on airport performance, but the airport does not have an appropriate organized response (this might be the case of heavy snow in Rome). In addition, convective weather might create disruptive conditions, even if the airport is well prepared to respond to weather.
Definition Source
ATM Airport Performance Framework (ATMAP) Measuring Airport Airside and Nearby Airspace Performance, December 2009
Note
Lexicon Release
Lexicon Release 2015.2
Downburst
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| Term | downburst |
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Abbreviation
Definition
A strong downdraft current of air from a cumulonimbus cloud, often associated with intense thunderstorms. Downdrafts may produce damaging winds at the surface.
Definition Source
United States, National Weather Service, glossary [5]
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Fog
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| Term | aircraft turbulence |
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Abbreviation
FG
Definition
A visible aggregate of minute water particles (droplets) in the air reducing the horizontal visibility at the Earth's surface to less than 1 kilometre.
Definition Source
ICAO (2000), official term, ICAO doc. 9640, Manual of Aircraft Ground De/Anti-icing Operation
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Horizontal wind shear
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| Term | horizontal wind shear |
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Abbreviation
Definition
change of horizontal wind direction and/or speed with horizontal distance, as would be determined by two or more anemometers mounted at the same height along a runway.
Definition Source
SKYBRARY, reference tool for aviation safety knowledge [6]
ICAO, doc. CIR 186
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In-flight icing
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| Term | in-flight icing |
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Abbreviation
Definition
Ice accreted on an aircraft structure and/or its engines and their air inlets as a result of flight in atmospheric icing conditions.
Definition Source
SKYBRARY, aviation safety knowledge reference tool, [7]
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Instrument Meteorological Conditions
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| Term | Instrument Meteorological Conditions |
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Abbreviation
IMC
Definition
Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, less than the minima specified for visual meteorological conditions.
Definition Source
ICAO (2007) Official definition modified by Amdt 16 to An 6/II (09/11/1995)
Note
Note 1.— [An 11] The specified minima for visual meteorological conditions are contained in Annex 2.
Note 2.— [PANS-ATM] In a control zone, a VFR flight may proceed under instrument meteorological conditions if and as authorized by air traffic control.
International Airways Volcano Watch
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| Term | International Airways Volcano Watch |
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Significant Meteorological Information(SIGMET) Volcanic Ash Advisory Centre (VAAC) |
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Abbreviation
IAVW
Definition
International arrangements for monitoring and providing warnings to aircraft of volcanic ash in the atmosphere.
Definition Source
ICAO, Official definition, Definition added to An 3 by Amdt 71 (5/11/1998) and modified by Amdt 72 to An 3,14th ed (1/11/2001).
Note
The IAVW is based on the cooperation of aviation and non-aviation operational units using information derived from observing sources and networks that are provided by States. The watch is coordinated by ICAO with the cooperation of other concerned international organizations.
International Standard Atmosphere
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| Term | International Standard Atmosphere |
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Abbreviation
ISA
Definition
variation of air temperature, pressure, and density with height above mean sea level. Used to normalize the results of aeroplane design calculations and to analyse test data.
Definition Source
ICAO (2008) DOC 9911 Recommended Method for Computing Noise Contours Around Airports 2008, 1st ed., p. (x)
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Intertropical convergence zone
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| Term | intertropical convergence zone |
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Abbreviation
ITCZ
Definition
a belt of low pressure which circles the Earth near the equator where the trade winds of the Northern and Southern Hemispheres come together. It is characterised by convective activity which generates often vigorous thunderstorms over large areas. It is most active over continental land masses by day and relatively less active over the oceans.
Definition Source
SKYBRARY (aviation safety knowledge reference tool) [8]
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Low Level Wind Shear Alert System
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| Term | Low Level Wind Shear Alert System |
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Abbreviation
LLWAS
Definition
a ground-based system for detecting the existence of wind shear close to an aerodrome.
Definition Source
SKYBRARY, reference tool for aviation safety knowledge [[9]]
Note
Meteorological Watch Office
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| Term | Meteorological Watch Office |
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Abbreviation
MWO
Definition
A meteorological office designated to:
— maintain watch over meteorological conditions affecting flight operations within its area of responsibility (a Flight Information Region (FIR) or a control area or combinations thereof);
— prepare SIGMET and other information related to its area of responsibility;
— supply SIGMET information and, as required, other meteorological information to associated air traffic services units (i.e. ACC or FIC);
— disseminate SIGMET information;
— supply information received on pre-eruption volcanic activity, a volcanic eruption and volcanic ash cloud for which a SIGMET has not already been issued, to its associated ACC/FIC, as agreed between the meteorological and ATS authorities concerned, and to its associated Volcanic Ash Advisory Centre (VAAC) as determined by regional air navigation agreement; and
— supply information received concerning the accidental release of radioactive materials into the atmosphere, in the area for which it maintains watch or adjacent areas, to its associated ACC/FIC, as agreed between the meteorological and ATS authorities concerned, and to aeronautical information service units, as agreed between the meteorological and appropriate civil aviation authorities concerned.
Definition Source
ICAO, Doc. 9377 Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (2008)
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Meteorological office
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| Term | meteorological office |
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MET office |
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Abbreviation
Definition
An office designated to provide meteorological service for international air navigation.
Definition Source
ICAO (2010), Annex 3, Meteorological Service for International Air Navigation
Note
A meteorological office and/or aerodrome meteorological office carries out all or some of the following functions to meet the needs of flight operations at aerodromes:
— prepare and/or obtain forecasts and other relevant information (e.g. aerodrome warnings and wind shear warnings and alerts)...;
— prepare and/or obtain forecasts of local meteorological conditions (e.g. aerodrome forecasts (TAF));
— maintain a continuous survey of meteorological conditions over the aerodromes for which it is designated to prepare forecasts;
— provide briefing, consultation and flight documentation to flight crew members and/or other flight operations personnel;
— supply other meteorological information to aeronautical users, including associated ATS units (usually TWRs and APPs);
— display the available meteorological information;
— exchange meteorological information with other meteorological offices; and
— supply information received on pre-eruption volcanic activity, a volcanic eruption and volcanic ash cloud to its associated air traffic services unit, aeronautical information services unit and meteorological watch office as agreed between the meteorological, aeronautical information service and ATS authorities concerned.
Note Source
ICAO (2008), doc. 9377 Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services
Meteorological services
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| Term | meteorological services |
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Abbreviation
MET
Definition
Those facilities and services that furnish aviation with meteorological forecasts, briefs and observations as well as SIGMET information, VOLMET broadcasting material and any other meteorological data provided by States for aeronautical use.
Definition Source
ICAO (2011), doc. ATREPF-K, Air Navigation Services Financial Data
Note
Microburst
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| Term | microburst |
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Abbreviation
Definition
A downburst that covers an area less than 4 km along a side with peak winds that last 2–5 minutes.
Differential velocity across the divergence center is greater than 10 m s−1. The strong wind shears associated with a microburst can result in aircraft accidents.
Definition Source
United States, National Weather Service, glossary [10]
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Mountain waves
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| Term | mountain waves |
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Abbreviation
Definition
oscillations to the lee side (downwind) of a mountain caused by the disturbance in the horizontal air flow caused by the high ground.
Definition Source
SKYBRARY, reference tool for aviation safety knowledge [11]
Note
Nominal weather condition
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| Term | nominal weather condition |
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Abbreviation
Definition
a weather condition which is excellent or good to conduct airport operations: CAVOK, favourable winds, etc.
Definition Source
ATM Airport Performance Framework (ATMAP) Measuring Airport Airside and Nearby Airspace Performance, December 2009
Note
Lexicon Release
Lexicon Release 2015.2
Pilot weather report
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| Term | pilot weather report |
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Abbreviation
PIREP
Definition
A report by a pilot pertaining to weather conditions encountered in flight.
Definition Source
Transport Canada (2010) Glossary for Pilots and Air Traffic Services Personnel (TP 11958E) [12]
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Planetary boundary layer
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| Term | planetary boundary layer |
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Abbreviation
Definition
The lower part of the troposphere which is directly influenced by the surface of the Earth.
Definition Source
SKYBRARY, reference tool for aviation safety knowledge [13]
Note
Pressure altimeter
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| Term | pressure altimeter |
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barometric altimeter |
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Abbreviation
Definition
An aneroid barometer calibrated to convert atmospheric pressure into altitude.
Definition Source
American Meteorological Society, Glossary of Meteorology [14]
Note
Altimeters use standard atmosphere pressure–height relations in converting pressure into altitude. Therefore, the altimeter shows indicated altitude, which may, and frequently does, differ from the actual altitude. An altimeter may be set to measure altitude from an arbitrarily chosen level. It is common practice to use mean sea level; the level of the constant-pressure surface of 29.92 in. of mercury is also used; and, less frequently, the constant-pressure surface of the pressure at airport height. See altimeter setting, pressure altitude. (same source)
Regional area forecast centre
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| Term | regional area forecast centre |
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Abbreviation
RAFC
Definition
A meteorological centre designated to prepare and supply significant weather forecasts and upper wind and temperature charts for flights departing from aerodromes within its service area and to supply grid point data in digital form for up to worldwide coverage.
Definition Source
ICAO, Official definition, ANNEX 3 Meteorological Service for International Air Navigation 2004
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SNOWTAM
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| Term | ' |
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Abbreviation
Definition
A special series NOTAM notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the movement area, by means of a specific format
Definition Source
ICAO DOC 8400 Procedures for Air Navigation Services — ICAO Abbreviations and Codes 2004, 6th ed.
Note
Significant Meteorological Information
| Link | Semantic Value |
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| Term | Significant Meteorological Information |
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Significant Meteorological Message |
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Abbreviation
SIGMET
Definition
Information concerning en-route weather phenomena which may affect the safety of aircraft operations.
Definition Source
ICAO, Official definition, Doc. 8400/4 (2004)
Note
Space weather
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| Term | space weather |
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Abbreviation
Definition
Conditions on the sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health of aviation flight crews and passengers.
Definition Source
World Meteorological Organisation (2008) Space Programme SP-5, the Potential Role of WMO in Space Weather
Note
Tropical cyclone
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Abbreviation
Definition
Generic term for a non-frontal synoptic-scale cyclone originating over tropical or sub-tropical waters with organized convection and definite cyclonic surface wind circulation.
Definition Source
ICAO, Official definition, Annex 3: Meteorological Service for International Air Navigation (2010)
Note
Tropical cyclone advisory centre
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| Term | tropical cyclone advisory centre |
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Abbreviation
TCAC
Definition
A meteorological centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, world area forecast centres and international OPMET data banks regarding the position, forecast direction and speed of movement, central pressure and maximum surface wind of tropical cyclones.
Definition Source
ICAO, Official definition, Annex 3: Meteorological Service for International Air Navigation (2010)
Note
Vertical visibility
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| Term | vertical visibility |
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Abbreviation
VV
Definition
The distance one can see upward into a surface based obscuration; or the maximum height from which a pilot in flight can recognize the ground through a surface based obscuration.
Definition Source
FAA, NOAA, "Aviation Weather", Glossary of Weather Terms [15]
Note
(followed by figures in METAR/SPECI and TAF)
Vertical wind shear
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| Term | vertical wind shear |
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Abbreviation
Definition
change of horizontal wind direction and/or speed with height, as would be determined by means of two or more anemometers mounted at different heights on a single mast.
Definition Source
SKYBRARY, reference tool for aviation safety knowledge [16]
ICAO, doc. CIR 186, 1987, p. 154
Note
Volcanic Ash Advisory Centre
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| Term | Volcanic Ash Advisory Centre |
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Abbreviation
VAAC
Definition
A meteorological centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, area control centres, flight information centres, world area forecast centres and international OPMET databanks regarding the lateral and vertical extent and forecast movement of volcanic ash in the atmosphere following volcanic eruptions.
Definition Source
ICAO, Official definition, added to An 3 by Amdt 71 (5/11/1998)
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Volcanic ash
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| Term | volcanic ash |
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Abbreviation
Definition
Fine particles of mineral matter from a volcanic eruption which can be dispersed long distances by winds aloft.
Definition Source
UNITED STATES, National Oceanic and Atmospheric Administration's National Weather Service (NOAA) Glossary [17]
Note
The chemical composition and abrasiveness of the particles can seriously affect aircraft and also machinery on the ground. If it is blown into the stratosphere and it is thick enough, it can decrease the global temperature
Wind shear
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| Term | wind shear |
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Definition
"A change in wind speed and/or wind direction in a short distance, resulting in a tearing or shearing effect. It can exist in a horizontal or vertical direction, and occasionally in both."
Definition Source
NATO: NORTH ATLANTIC TREATY ORGANIZATION, Advisory Group for Aerospace Research and Development (AGARD/NATO) (1980), "Agard Multilingual Aeronautical Dictionary", Second Edition, London
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World Area Forecast Centre
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| Term | World Area Forecast Centre |
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WAFC
Definition
A meteorological centre designated to prepare and issue significant weather forecasts and upper-air forecasts in digital form on a global basis direct to States by appropriate means as part of the aeronautical fixed service.
Definition Source
ICAO, Official definition, Annex 3: Meteorological Service for International Air Navigation (2010)
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