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SIGMET
SIGMET, or Significant Meteorological Information (AIM 7-1-6), is a severe weather advisory that contains meteorological information concerning the safety of all aircraft. Compared to AIRMETs, SIGMETs cover more severe weather. Types There are three main types of internationally recognized SIGMETs per ICAO: * Volcanic ash (VA or WV SIGMET) * Tropical Cyclone (TC SIGMET) * Other En-route weather phenomenon (WS SIGMET), which may consist of ** Thunderstorm types ** Turbulences types ** Mountain waves ** Icing/Sleet/Hail ** Dust or sand storms ** Radioactive Cloud This information is usually broadcast on the ATIS at ATC facilities, as well as over VOLMET stations. They are assigned an alphabetic designator from N through Y (excluding S and T). SIGMETs are issued as needed, and are valid up to four hours. SIGMETS for hurricanes and volcanic ash outside the CONUS are valid up to six hours. Convective SIGMETs For airmen in the U.S., there is an additional category of SIGMET kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AIRMET
An AIRMET, or Airmen's Meteorological Information, is a concise description of weather phenomena that are occurring or may occur (forecast) along an air route that may affect aircraft safety. Compared to SIGMETs, AIRMETs cover less severe weather: moderate turbulence and icing, sustained surface winds of 30 knots or more, or widespread restricted visibility. Types AIRMETs are broadcast on the ATIS at ATC facilities, and are referred to as Weather Advisories. AIRMETs are valid for six hours.ICAO Annex 3 Chapter 7 NOTE: The definition has changed and no longer says "light aircraft"; AIRMETs are intended for ''all'' aircraft. There are three types of AIRMET, all identified by a phonetic letter: S (Sierra), T (Tango), and Z (Zulu). * AIRMET SIERRA (Mountain obscuration or IFR) ceiling (cloud), ceilings less than 1000 feet and/or visibility less than 3 miles affecting over 50% of the area at one time; extensive mountain obscuration *AIRMET TANGO (Turbulence) moderate turbulenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IWXXM
IWXXM (ICAO Meteorological Information Exchange Model) is a format for reporting weather information in XML/ GML. IWXXM includes XML/ GML-based representations for products standardized in International Civil Aviation Organization (ICAO) Annex III and World Meteorological Organization (WMO) No. 49, Vol II, such as METAR/ SPECI, TAF, SIGMET, AIRMET, Tropical Cyclone Advisory, Volcanic Ash Advisory and Space Weather Advisory. IWXXM products are used for operational exchanges of meteorological information for use in aviation. Unlike the traditional forms of the ICAO Annex III / WMO No. 49 products, IWXXM is not intended to be directly used by pilots. IWXXM is designed to be consumed by software acting on behalf of pilots, such as display software. History IWXXM Version 1 was introduced in October 2013, representing METAR, SPECI, TAF and SIGMET formats as specified in International Civil Aviation Organization (ICAO) Annex III, Amendment 76. IWXXM became an optional format for the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VOLMET
{{Use dmy dates, date=December 2021 VOLMET (French origin ''vol'' (flight) and ''météo'' (weather report)), or meteorological information for aircraft in flight, is a worldwide network of radio stations that broadcast TAF, SIGMET and METAR reports on shortwave frequencies, and in some countries on VHF too. Reports are sent in upper sideband mode, using automated voice transmissions. Pilots on international routes, such as North Atlantic Tracks, use these transmissions to avoid storms and turbulence, and to determine which procedures to use for descent, approach, and landing. The VOLMET network divides the world into specific regions, and individual VOLMET stations in each region broadcast weather reports for specific groups of air terminals in their region at specific times, coordinating their transmission schedules so as not to interfere with one another. Schedules are determined in intervals of five minutes, with one VOLMET station in each region broadcasting reports ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PIREP
A pilot report or PIREP is a report of actual flight or ground conditions encountered by an aircraft. Reports commonly include information about atmospheric conditions (like temperature, icing, turbulence) or airport conditions (like runway condition codes or ground equipment failures). This information is usually relayed by radio to the nearest ground station, but other options (e.g. electronic submission) also exist in some regions. The message would then be encoded and relayed to other weather offices and air traffic service units. Although the actual form used to record the PIREP may differ from one country to another, the standards and criteria will remain almost the same. At a minimum the PIREP must contain a header, aircraft location, time, flight level, aircraft type and one other field. In recent years, a PIREP will also include UA or UUA used to identify the PIREP as routine or urgent. Included data Mandatory *UA or UUA used to identify the PIREP as routine or urge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature, precipitation, and other atmospheric conditions, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth. Weather is driven by air pressure, temperature, and moisture differences between one place and another. These differences can occur due to the Sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley cell, the Ferrel cell, the polar cell, and the jet stream. Weather system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorological
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 phenom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, paramotors, and hot air balloons. The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called '' aeronautics.'' Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Terminal Information Service
Automatic terminal information service, or ATIS, is a continuous broadcast of recorded aeronautical information in busier terminal areas, i.e. airports and their immediate surroundings. ATIS broadcasts contain essential information, such as current weather information, active runways, available approaches, and any other information required by the pilots, such as important NOTAMs. Pilots usually listen to an available ATIS broadcast before contacting the local control unit, which reduces the controllers' workload and relieves frequency congestion. In the US, ATIS will include (in this order): the airport or facility name; a phonetic letter code; time of the latest weather observation in UTC time; weather information consisting of wind direction and velocity, visibility, obstructions to vision, sky condition, temperature, dew point, altimeter setting, density altitude advisory if appropriate; and other pertinent remarks, including runway in use. If it exists, the weather observatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Traffic Control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of air traffic, and provide information and other support for pilots. Air traffic controllers monitor the location of aircraft in their assigned airspace by radar and communicate with the pilots by radio. To prevent collisions, ATC enforces traffic separation rules, which ensure each aircraft maintains a minimum amount of empty space around it at all times. In many countries, ATC provides services to all private, military, and commercial aircraft operating within its airspace. Depending on the type of flight and the class of airspace, ATC may issue ''instructions'' that pilots are required to obey, or ''advisories'' (known as ''flight infor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NATO Phonetic Alphabet
The (International) Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet, is the most widely used set of clear code words for communicating the letters of the Roman alphabet, technically a ''radiotelephonic spelling alphabet.'' It goes by various names, including NATO spelling alphabet, ICAO phonetic alphabet and ICAO spelling alphabet. The ITU phonetic alphabet and figure code is a rarely used variant that differs in the code words for digits. To create the code, a series of international agencies assigned 26 code words acrophonically to the letters of the Roman alphabet, with the intention of the letters and numbers being easily distinguishable from one another over radio and telephone, regardless of language barriers and connection quality. The specific code words varied, as some seemingly distinct words were found to be ineffective in real-life conditions. In 1956, NATO modified the then-current set of code words used by the International ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contiguous United States
The contiguous United States (officially the conterminous United States) consists of the 48 adjoining U.S. states and the Federal District of the United States of America. The term excludes the only two non-contiguous states, Alaska and Hawaii (also the last ones admitted to the Union), and all other offshore insular areas, such as American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands. The colloquial term "Lower48" is used also, especially in relation to just Alaska (Hawaii is farther south). The related but distinct term continental United States includes Alaska (which is also on the continent of North America but separated from the 48 states by British Columbia and Yukon of Canada), but excludes the Hawaiian Islands and all U.S. territories in the Caribbean and the Pacific. The greatest distance (on a great-circle route) entirely within the contiguous U.S. is 2,802 miles (4,509 km), between Florida and the State of Washington; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference layer in the atmosphere. Different lapse rates within dry and moist air masses lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to increased winds, cumulus cloud development, and decreased surface dew points. Moist convection leads to thunderstorm development, which is often responsible for severe weather throughout the world. Special threats from thunderstorms include hail, downbursts, and tornadoes. Overview There are a few general archetypes of atmospheric instability that are used to explain convection (or lack thereof). A necessary (but not sufficient) condition for convection is that the environmental lapse rate (the rate of decrease of temperature with height) is steeper than the lapse rate experienced by a rising parcel of air. When this condition is met, upward-displaced air parcels can become buoyant and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
