An updraft or downdraft (air pocket) is the vertical movement of air as a weather related phenomenon. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five The weather is a set of all the phenomena occurring in a given Atmosphere at a given Time. Commonly, one of two forces causes the air to move. Localized regions of warm or cool air will exhibit vertical movement. A pocket of warm air will typically be less dense than the surrounding region, and so will rise until it reaches air that is either warmer or less dense than itself. The converse will occur for a mass of cool air, and is known as subsidence. Subsidence in the Earth's atmosphere is most commonly caused by cold temperatures as air cools it becomes denser and moves towards the ground just as warm air becomes less This movement of large volumes of air, especially when regions of hot, wet air rise, can create large clouds, and is the main cause of thunderstorms. Drafts can also be created by low or high pressure regions. A low pressure region will attract air from the surrounding area, which will move towards the center and then rise, creating an updraft. The reverse will naturally occur in a high pressure region, as air moves away from the high pressure center.
Notable effects
Updrafts and downdrafts are some of the main causes of in-flight turbulence in planes, and are one reason airlines try to avoid regions of bad weather. Extreme cases, known as downbursts and microbursts are responsible for many airplane crashes. Downburst damagejpg|thumb|right|300px|Downburst damages in a straight line A microburst is a very localized column of sinking air producing damaging divergent and Straight-line winds at the surface that are similar to but distinguishable from The crash of Delta Air Lines Flight 191 on their final approach leg before landing in 1985 was presumably caused by a microburst, and prompted the Federal Aviation Administration to research and deploy new storm detection radar stations at some of the major airports. Delta Air Lines Flight 191 was an Airline service from Fort Lauderdale Florida 's Fort Lauderdale-Hollywood International Airport, bound for Los Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar) The Federal Aviation Administration ( FAA) is an agency of the United States Department of Transportation with authority to regulate and oversee all aspects of
Downbursts can cause extensive localized damage, similar to that caused by tornadoes. A tornado is a violent rotating column of air which is in contact with both the surface of the earth and a Cumulonimbus cloud or in rare cases the base of a Cumulus Downburst damage can be differentiated from that of a tornado because the resulting destruction is circular and radiates away from the center. Tornado damage radiates inward, towards the center of the damage.
See also
- Air safety
- Thermal
- Wind shear
- Atmospheric thermodynamics
- New Zealand National Airways Corporation Flight 441 — airplane crash linked to severe downdraft
- Lee waves
- NEXRAD
- Downdraft Table
External links
Air safety is a term encompassing the theory investigation and categorization of flight failures, and the prevention of such failures through regulation as well as through A Low level windshear alert system (LLWAS measures wind speed and direction at remote sensor station sites situated around an airport A thermal column (or thermal) is a column of rising Air in the lower altitudes of the Earth's atmosphere. Wind shear, sometimes referred to as windshear or Wind gradient, is a difference in Wind speed and direction over a relatively In the Physical sciences atmospheric thermodynamics is the study of Heat and Energy transformations in the earth’s atmospheric system New Zealand National Airways Corporation Flight 441 was a scheduled flight of New Zealand's National Airways Corporation from Whenuapai to Tauranga In Meteorology, lee waves, are atmospheric Standing waves. The most common form is mountain waves, which are atmospheric internal Gravity NEXRAD or Nexrad ( Nex t-Generation Rad ar is a network of 158 high-resolution Doppler Weather radars operated by the National Weather Downdraft Tables provide Workstations with built in ventilation to capture and filter dust smoke and fumes and then return the filtered air to a shop floor which can eliminateDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic