Atmosphere
Where is the tropopause the thickest - the poles or the equator?
THICCCCEST - EQUATOR 55k-60k
mid latitudes - 35k-40k
thin - poles 25k-30k
How does pressure vary with altitude?
Pressure decreases as altitude increases. In the standard atmosphere the rate of decrease is 1 inch Hg per 1,000 feet
What is the dew point?
The temperature at which air reaches water vapor saturation
What is CAT?
Turbulence not associated with clouds. Occurs at high altitudes near the jet stream
How might an inversion affect visibility?
Inversions create a capping effect, trapping haze, fog, or smog near the surface
What is the standard lapse rate?
2 degrees Celsius per 1,000 feet
What is Coriolis force?
Phenomenon that occurs due to the rotation of the Earth that causes wind in the Northern Hemisphere to be deflected to the right.
What is the significance of virga?
It is precipitation that evaporates before it reaches the ground.
associated with turbulence/unstable conditions
What is a squall line?
A squall line is a line of severe thunderstorms forming ahead typically of a fast moving cold front
What is the tropopause?
Division between troposphere and stratosphere marked by a dramatic lapse rate change or the temperature stops changing as alt increases.
What effect does temperature have on aircraft performance?
As temperature increases, aircraft performance is REDUCED due to a decrease in air density.
Define isobar
Define trough
Define ridge
Trough: Elongated area of low pressure
Ridge: elongated area of high pressure
As air expands....
temperature decreases
What is a microburst?
A concentrated area of wind shear that flows downward and outward from a strong thunderstorm. Should be avoided at all times
What is the jet stream?
Narrow band of strong wind, over 50kts, occuring in the upper atmosphere
Where the tropopause changes altitude dramatically over a short distance the jet stream can be here and (turbulence)
What potential might arise when an inversion exists at an airport?
reduces visibility
wind shear at the inversion layer
What is katabatic wind?
Wind flowing along an inclined surface. Common in mountainous areas caused by cold, dense air rapidly sinking downwards along the sloping terrain.
What is a "front"
At least 20NM around and at least 1,000 feet per 10kts of wind above the cloud tops
CAT can be produced by jet stream winds in excess of ____ kts or more
100
What is the difference between pressure and density altitude?
Pressure: altitude above the standard datum plane (altimeter set to 29.92), read the altitude shown
Density: pressure altitude corrected for temperature and humidity - directly affecting aircraft performance
Define "wind shear"
Rapid shift in wind speed or direction
What is a dry line front?
Common in Texas, dry area from west desert impinges on moist air from the Gulf. Can produce thunderstorms
dry line vs cold and warm fronts
cold/warm vary between temperature
dry line is differing moisture contents
What are the three types of icing?
What clouds are they found in?
How does an aircraft deviate from them?
Clear, Mixed, Rime
Rime in stratus clouds, Clear in cumulus clouds
Deviate on a new route to escape Clear
Deviate at a new altitude to escape Rime
Is icing typically a concern at high altitudes?
No, clouds in upper levels of the atmosphere are made of ice crystals