5 - Atmospheric Stability Flashcards
Adiabatic Process (AP)
A process in which no heat is transferred into or out of a system, simply isolated
- No energy transfer
- Wind: not possible without mixing
- As volume increases, pressure increases
Factors that varies the AP
1 - Turbulence
2 - Heat Exchange
Key points of the AP
- No exchange of mass/energy
- Rising, temp. decreases: expand to create space, loss of energy
- Compressing, temp. increases
- Solar radiation, temp. increases
Key points of water vapour
- Assume there is none
- 0-4%, temp. decreases, dew point = condensation
- Latent heat is released
- Self contained, not mixed with external
Lifting Condensation
- Clouds = lifting condensation
- Dew point + condensation
If Tp < Ta…
Air parcel will SINK (stable)
If Tp > Ta…
Air parcel will RISE (unstable)
If Tp = Ta…
Air parcel is NEUTRAL
- Indifferent, stays the same
What happens at the equilibrium level?
Clouds stop existing
If T’p < T’a…
STABLE
- Sink to the original height/altitude
If T’p > T’a…
RISE FOREVER iff warmer than its environment
If T’p = T’a…
NEUTRAL
Helium balloon vs Normal balloon
Helium
- Adiabatic
- Rises = unstable
Normal
- Take in account the weight of the balloon
- Sink = stable
Boyle’s Law
- Scuba diving example
- Pressure latent force
- Air needs to escape but it can’t
- 2m height
If Γ < Γd…
Condition of stability
- Temperature decreases
If Γ < Γw…
Absolutely stable
- Release of heat
- Dry/wet/moist adiabatic temp. lapse rate decreases at a higher rate than the temperature
Γd (Dry Adiabatic Temperature Lapse Rate)
Γw (Wet Adiabatic Temperature Lapse Rate)
for UNSATURATED air
for SATURATED air
Absolute Stability
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Absolute Instability
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Conditional Instability
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