Meteorology Flashcards
Composition of the Atmosphere:
Nitrogen - 78% Oxygen - 21% Water Vapour - 0 to 3% Carbon Dioxide - 0.03% Other Gases
What is Condensation Nuclei?
Tiny suspended particle, solid or liquid which water vapour condenses on
What is the most important component of the atmosphere in terms of weather?
Water Vapour
Know Changes of State for Water
Yes Sir
True or False: The ability of the atmosphere to hold moisture increases with temperature?
True
3 Principle Properties of the Atmosphere:
Expansion - As air rises, it expands and cools water vapour may condense
Compression - Sinking air contracts and is heated clouds dissipate
Mobility - Both horizontally and vertically
What is more dense cold air or warm air?
Cold air is denser and tends to sink, warm air rises
Explain what Dewpoint is:
Temperature at a given pressure to which air must be cooled to cause saturation
What happens when air becomes fully saturated?
Water vapour will condense into clouds/fog
What is the difference between the temperature and the dewpoint called?
The spread - provides information of how close the air is to saturation and the likelihood of fog forming
What is the Dewpoint Lapse Rate?
0.5 C / 1000’
What is Relative Humidity?
Water vapour content of the air as a percentage of the maximum possible at current temperature (saturation)
Facts about the Troposphere:
- Surface to 28,000’ (Poles) - 54,000’ (Equator)
- Weather occurs here
- Pressure, temperature, density decrease with altitude
- Temperature decrease stops and remains steady at -56 C
Facts about the Stratosphere:
- Up to 160,000’
- Temperature constant at -56 C in lower portions, and rises to -15 C (ozone)
- Clouds rare, visibility good
Facts about the Mesosphere:
- Temperature decreases to approx. 275,000’
- Point at which temperature increase is called mesopause
Facts about the Thermosphere:
- Temperature increases into thousands of degrees
- Aurora occurs in this layer
What kind of energy is emitted by the sun?
Short Wave UV radiation
Give the distribution of Solar Energy absorption
19% Absorbed by Ozone 6% Reflected by Atmosphere 20% Reflected by Cloud Tops 4% Reflected by Earth's Surface 51% Absorbed by Earth's Surface
Heating Processes
Conduction - Heating through contact (limited air is a poor conductor)
Convection - Air that is warmed tends to rise, rising tendency until density is equal to surrounding air
Turbulent Mixing - Friction causes eddies as air moves over surfaces, disruption is proportionate to terrain
Advection - Horizontal movement of air masses (over warm surface, it will be warmed)
Compression - Descending air increases in pressure, increasing temperature, along ridges of mountain ranges (adiabatic heating)
Release of Latent Heat - Changing state releases heat energy (down an energy level)
Cooling Processes
Expansion - Rising air decreases in temperature, adiabatic cooling, occurs at two different lapse rates depending on moisture (DLAR: 3C/1000’ & SLAR: 1.5C/1000’)
Orographic/Upslope Lift: Result of air flowing over topographical features causes air to rise
Frontal Lift: Expansion cooling when warm air is forced up along a frontal surface, Cold fronts: displaces warm air causes it to rise, Warm fronts: Can’t displace cold air rises up over cold air
Mechanical Turbulence: Same mechanism as heat distribution process
Convection: Rising air cools according to lapse rate
Convergence: Air at centre of a low rises, causes cooling
Advection: Air mass moving over cold surface will cool
Evaporation: Opposite of condensation, liquid to gas heat is absorbed
What does Atmospheric Stability refer to?
Resistance to vertical movements of air parcels
How is Stability determined?
Determined by the temperature difference between rising air parcel and surrounding air
What does a Steep and Shallow Lapse Rate indicate?
Steep Lapse Rate implies unstable air
Shallow Lapse Rate implies stable air
What is Inversion?
Temperature increase with height, indicated extremely stable air