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30 Cards in this Set
- Front
- Back
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Meteorology |
study of both water and climate |
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Composition of Air |
Argon - 0.93% Carbon dioxide - 0.03% Nitrogen - 78.00% Oxygen - 21.00% |
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ICAO |
International Civil Aviation Organization |
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what is the standard atomsphere of dry air at mean sea level |
standard atomsphere of dry air
Pressure = 1013.25 millibars (hectopascals) Temperature = 15 celsius Density = 1225g/m^3
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temperature Above mean sea level |
standard atomsphere of dry air
-temperature decrease by -6.5 celsius / km up to 11km - -56.5 clsius at 11km to 20km - temperature increase by 1 celsius / km from 20 to 32km |
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draw the sphere |
temperature lapses with height in the troposphere temperature remains constant at an altitude known as tropopause stratosphere -> above the tropopause |
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Isobar |
line joining all places having the same pressure of a given level (mean sea level) |
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what is L, S, H, COL in an isobar graph |
L = Low or depression S = Secondary depression H = High or anticyclone
COL = area of almost uniform pressure between 2 high and 2 low |
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Pressure gradient |
rate of change of pressure per unit distance, measured in the direction in which pressure decreases most rapidly |
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isobar that are wide apart |
slack pressure gradient |
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isoboard that are close together |
steep pressure gradient |
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QFF |
Field elevation barometric pressure at a place, reduced to mean sea level |
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QNH |
nautical height observed barometric pressured reduced at the msl, assuming iSA condition |
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QNE |
nautical elevation height (pressure altitude) indicated on teh altmeter on landing at an aerodrome when the altimeter subscale is set to 1013.25mb (29.92in) aka standard setting |
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Temperature lapse rate |
rate of decrease of temperature per unit increase of height |
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ELR |
Envrionmental Lapse rate (ELR) observed rate of decrease of temperature with the increase of height at a particular place of time |
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DALR |
dry adiabatic lapse rate (dalr) - for a parcel of dry air rising under adiabatic condition - rate of cooling with ascent or warming with descent of unsaturated air displaced vertically in which the temperature change due entirely to dynamical processes and there is no exchange of heat w/ the environment 3 degree / 1000ft |
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SALR |
Saturated Adiabatic lapse rate - 1.5 degree / 1000ft - rate of cooling with ascent of saturated air in which the expansion cooling is partly offset by the latent heat of condensation and no exchange of heat with environment of rising saturated and where condensation occurs and release latent heat |
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draw diagram of DALR and SALR |
draw them |
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how are cloud formed? |
adiabatic cooling
- air is cooled so that it becomes saturated - excess water vapour then condense out onto condensation nuclei as visible water drop or ice crystal |
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how is the water cooled? |
1. long wave radiation form the upper surface of preexisting cloud may lead to enough cooling to produce further cloud 2. contacting with a cloud surface, so losing heat from the air by conduction 3. mixing 2 nearly saturated masses of air at markedly different temperature |
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types of cloud |
1. orographic cloud 2. convection cloud 3. turbulence cloud 4. frontal cloud (warm front + cold front) |
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orographic cloud |
formed due to the ascent of air over high or rising ground |
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convection cloud |
formed due to surface heating of air producing stable thermal up current |
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turbulence cloud |
formed due to air flow producing a frictional turbulence layer caused either by underlying earth's surface or the upper level |
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frontal cloud |
formed when there is a general ascent of air over a wide area |
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type of frontal cloud |
warm front and cold front |
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warm front |
volume of moist air moves forward and subsequently overtakes a mass of cold air, the warm air becomes less dense, rise over the cold - temperature of warm air will fall and at a certain level, moisture starts to condense out in the formation of cloud |
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indication of warm front |
approaching from cold sector is by type of cloud expereinced.
change of cloud type is experienced by a gradual thickening and progressive lowering of the cloud base as base of front is approached
600 miles or so ahread of the front - cirrus will be expereinced, formed at 25000 to 300000 feet
Cirrus, cirrostratus, altostratus, nimbostratus, then stratus (pilots use the acronym CCANS). Other clouds can also often be seen,
http://en.wikipedia.org/wiki/Warm_front |
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cold front |
cold front advances its way underneath the warm air warm air force to rise quite rapidly warm air however ascends only in lower levels @higher level, it descends along the line of front so taht at some middle level, there is a horiziontal movement of warm air in the general direction of the line of advance? - if relative movement of air is very unstable -> temperature change of its mass decrease abnormally with height then large cumulus clouds will predominate which mag will develop into cumulonimbus extending the whole line of the front. -> if stable, - slope of front is less steep of cloud associated with it is a combination of layer type cloud made up of stratocumulus or altocumulus and attostratus w/ occasional cumulus or cumuloninbus embedded in it
Often preceded by cirrus, cirrostratus then altostratus like a warm front (but usually with smaller amounts of these clouds).
http://en.wikipedia.org/wiki/Cold_front |
