Atmosphere & Weather Flashcards
Atmosphere composed of % gases
78% Nitrogen
21% Oxygen
1% other (0.93% Argon)
99% of the atmosphere lies within
19 miles of the Earths surface
% for Nitrogen and Oxygen hold constant upto
about 50 miles
Changing of water vapor into liquid water
Condensation
Liquid water becoming water vapor
Evaporation
Latent Heat
Released when water turns from Vapor to liquid water or ice
Atmosphere Spheres
Troposphere Stratosphere Mesosphere Thermosphere Exosphere
Isothermal Zones
Region where the air remains constant with height
Temperature decrease with height
Lapse rate
Lapse Rate average
2*C per 1000 feet rise elevation
Temperature Inversion
Temperature may increase with height
Troposphere
From the earths surface to where the air stops becoming colder with height
Jet Stream
Narrow, shallow band of strong westerly winds of 50 knots or more around the hemisphere in a wave like pattern
Ozone
it absorbs energetic ultraviolet solar energy
Hypoxia
oxygen starved, no pain, feeling of exhaustion, visual impairment, carelessness, unconsciousness and death.
Exosphere
Region where atoms and molecules shoot off into space
Weather Fronts
Cold, Warm, Occluded, Stationary
Cold Front
Cold air mass overtaking warm air mass. Turbulence, wind shear,TS, lighting, heavy rain, hail, icing and tornados.
Warm Front
Warm air mass overtaking and replacing a cold front. Low ceiling and poor visibility, freezing rain, ice. 6-12hrs prior to and 1hr afterwards.
Occluded Front
Cold front overtakes a warm front and lifts it completely from the ground.
Stationary Front
Warm or Cold front that just does not move.
Most noticeable property of air
Mobility
Winds on earth are impelled by 2 great forces
Heat of the sun
Rotation of the Earths axis
Real sourest that drives the winds
The Sun
Steering mechanism that drives the wind
Earths Rotation
Jet stream wind
May reach up to 300 knots but generally between 100 and 150 knots. Strongest winds between FL250 and FL400
Hydrologic Cycle
Water evaporates and condenses again falling down as precipitation in a never ending cycle
most important element in the production of clouds and other visible weather phenomena
Water Vapor
Absolute Humility
density of water vapor in the air.
Relative Humidity
Ratio of the amount of water vapor actually in the air to the maximum amount that the air can hold at the temperature.
Dew Point
is the temperature, at a given pressure, to which the air must be cooled to become saturated
Frost Point
When the Dew Point is bellow freezing
Spread
difference between the temperature and dew point
4*F of the dew point
Aircrews should be alert for the possibility of fog or low cloud formation
Atmospheric Pressure-Definition
the force per unit area exerted by the weight if a column of air directly above a given fixed point.
Pressure Units
inches of mercury (Hg)
millibars (mb)
hectopascals (hPa)
Kollsman Window
altimeters in the US aircraft are calibrated for settings in inches of mercury
Station Pressure
Pressure measured at an airport, it’s the weight of the air above the airport.
MSL Pressure
1 inch of mercury for each 1000 feet of altitude change.
Temperature
Air expands as it becomes warmer and contracts as it cools
Pressure Altitude (PA)
standard atmosphere, sea level pressure 29.92 inches Hg or 1013.2 mb.
Standard Datum Plane
29.92 in Hg
1013.2 mb
15*C
Density Altitude
Is pressure altitude corrected for nonstandard temperature.
QNE
always 29.92 Hg above the transition altitude FL180 MSL in the US
QNH
True height above MSL
QFE
DANGEROUS.
indicates actual elevation above the field. (will show ZERO feet on the ground)
Altimeter Errors
Atmospheric pressure
Mechanical Displacement
Instrument Error
