Atmosphere/Air Masses/Pressure/Wind/Moisture/Stability/Clouds Flashcards
Natural air contains a variable amount of______ and _____.
water vapor and condensation nuclei
The most important element of weather, usually not found above the troposphere, is _____.
moisture
Atmospheric circulation occurs in a three-cell pattern because of uneven heating of the Earth’s surface, the 23.5 degree tilt of the Earth, and _______.
the Coriolis effect.
The prevailing wind direction between 30 and 60 degrees latitudes moves FROM which direction?
West
The basic characteristics of any air mass are (two things)
temperature and moisture
Name a source region for a warm, moist air mass?
Gulf of Mexico
Bermuda High
What classification would describe cold, dry air mass?
cP
What classification would describe warm, moist air mass?
mT
Four types of heat transfer
Conduction-physical contact
Convection-gas in a vertical movement
Advection-wind in a horizontal movement
Radiation- electromagnetic waves (insolation- from the sun; terrestrial- from Earth)
A layer of air, characterized by an increase in temperature with altitude, is_____
temperature inversion
What would prevent a radiation (nocturnal) temperature inversion?
Overcast skies (Greenhouse effect)
Cold, dense air lifting warmer, less dense air is an example of what type of temperature inversion?
Frontal inversion (All fronts have a temperature inversion)
What is standard MSL pressure in inches of mercury and mb?
29.92 Hg and 1013.2 hp/mb
Sky conditions associated with low-pressure areas are normally produced by…
Rising and cooling of the air
What is an isobar?
lines connecting points of equal pressure correct to sea level usually spaced 4mb apart.
While flying parallel to the isobars above 2,000 feet ABL, the wind is approximately a head wind or tail wind and the pressure remains relatively constant. (T/F)
True
The wind aloft or gradient wind circulation around a high pressure area is
clockwise and parallel to the isobars
Surface wind that converges to the center is associated with (high/low) pressure areas, and surface wind that diverges from the center is associated with (high/low) pressure areas.
low
high
You are flying a course of 045 degrees with steady crosswind from 135 degrees. Based upon the wind direction, what kind of pressure and general weather conditions would you expect ahead?
High pressure area with clear skies and weak pressure gradient force
Flying on an easterly heading, you observe the aircraft drifting to the right. If you do not reset your altimeter as the flight progresses, you can expect the aircraft to be (higher/lower) than the indicated altitude.
lower
In the Northern hemisphere, if your back is to the wind, the low pressure will be on your (right/left).
left
Flying with left crosswind indicates flying toward a (low/high) pressure with possible altimeter errors and deteriorating weather.
low
Flying with right crosswind indicates flying toward a (low/high) pressure with possible altimeter errors and improving weather.
high
Which term belongs with the definition “ a direct change in moisture from vapor to a solid”?
deposition
sublimation-solid to gas
A large temperature/dewpoint spread indicates (high/low) relative humidity?
low
Air being lifted over a mountain range will cool on the windward side and heat up as it moves downslope on the leeward side. This temperature change is a result of the
adiabatic process
You would expect more clouds to form in
air rising up a mountainside
Two basic cloud forms
stratiform and cumuliform
What family of cloud would indicate an unstable atmospher?
Cumulus CU
Clouds associated with the nocturnal cooling process would be
low stratus and fog
When the word nimbus is added to the names of a cloud is means
some form of precipitation is associated with the cloud.
CU
vertical cloud without precipitation Cumulus
CB
Vertical cloud producing rain Cumulonimbus
SC
Cloud having both horizontal and vertical movements stratocumulus
NS
horizontal cloud producing rain nimbostratus
ST
horizontal cloud without rain stratus
