Meteorology Flashcards
What is the rough Composition of the Atmosphere?
79% Nitrogen
21% Oxygen
1% Argon
0.05% Other Gases
What is the Temperature Trends in the different divisions of the Atmosphere?
Troposphere - Down
Stratosphere - Up
Mesosphere - Down
Thermosphere - Up
Where does most weather in the atmosphere occur?
Troposphere
What is the height of the Troposphere over the poles vs the equator?
28,000’ over the poles
54,000’ over the equator
What is the ICAO Standard Atmosphere in terms of Mean Sea Level Pressure, Mean Sea Level Temperature, & Lapse Rate?
29.92” Hg
15°C
1.98°C/1000’
What are the 3 Principle Properties of the Atmosphere?
Expansion
Compression
Mobility
As moisture goes from Ice to Water is heat absorbed or released?
Absorbed
What is the Definition of Dewpoint?
Temperature, at a given pressure, to which air must be cooled to cause saturation
What is the Definition of Relative Humidity?
Compares amount of water vapour in the air to amount if could hold if it were saturated, expressed as a percentage
What is denser Cold Air or Warm Air?
Cold Air
What kind of radiation is Terrestrial Radiation?
Infrared
What are the 6 Atmospheric Heating Processes?
- Conduction - Heating through contact
- Convection - Warm air is less dense and tends to rise
- Turbulent Mixing - Friction causes eddies to form as air moves over surfaces
Advection - Horizontal movement of air masses
Compression - Descending air increasing in pressure, in turn increasing in temp
Release of Latent Heat - Changing state down an energy level
Which way does air flow around a High Pressure Centre?
Clockwise
Which way does air flow around a Low Pressure Centre?
Counter-Clockwise
Does air aloft converge or diverge around a High Pressure System?
Converge
What are the 6 Adiabatic Atmospheric Cooling Processes?
- Expansion Cooling - Rising air expands, cools according to lapse rate
- Orographic & Upslope Lift - Result of air flowing over features that cause air to rise
- Frontal Lift - Occurs when warm air forced up along a frontal surface
- Mechanical Turbulence - Same mechanism as warming
- Convection - Rising air cools according to lapse rate
- Convergence - Air at centre of low rises, causes cooling
What is the Dry Adiabatic Lapse Rate and the Saturated Adiabatic Lapse Rate?
DALR: 3°/1000’ (< 100% relative humidity)
SALR: 1.5°/1000’ (100% relative humidity)
What displaces what - cold air or warm air?
Cold Air displaces Warm Air
What are 2 other Cooling Processes?
- Radiation Cooling - Surface temps below air temps, surface emits heat into colder upper atmosphere
- Non-Expansional Cooling - Advection - air moving older colder surface. Evaporation - heat absorbed
Describe Stable, Unstable and Neutral Air?
Stable - Will return to original state
Unstable - Will move further way from original state
Neutral - Will remain at disturbed state
What determines Atmospheric Stability?
Temperature Difference between rising air parcel and surrounding air
What is an Isothermal Layer?
Temperature doesn’t change with change in altitude, very stable
What is an Inversion?
Temperature increases with height, extremely stable
What kind kind of Cloud is formed in Stable vs Unstable Air?
Layered (Stratiform) - Stable
Heaped (Cumuliform) - Unstable