Atmospheric Pressure and Buoyancy Flashcards
Parcel of air
Bubble of air with no definite size that retains shape and size as it rises or sinks in the atmosphere.
Moving from one height to another
Ideal gas law
Pressure is proportional to density and temperature
Pressure gradient force
Change in pressure proportional to change in thickness / area
Hydrostatic equilibrium
Fluid or plastic at rest; External forces gravity balanced by a pressure gradient force.
Pressure ratio with Scale Height (H)
Pressure decreases exp by e^-1 when height changes by H. Faster decrease for lower temps
Atmospheric thermal structure
Thermosphere (top)
Mesosphere
Stratosphere
Troposphere
mesopause, stratopause, tropopause at the top border of each
Atmosphere transparancy
transparent to solar radiation, opaque to IR
Flux to IR eqn
Absorbed IR Flux = Emitted IR Flux
Force of buoyancy
Fb = g(T-To / To) ^ p<po | if parcel of air warmer and less dense than surroundings, force of buoyancy is upwards.
Adiabatic process
No heat exchanged between parcel and surrounding atmosphere deltaQ = 0
Rising parcel of air
- surrounding pressure decreases
- parcel expands as pressure adjusts to environment P = Po
- boundaries of parcel doing work against surrounding
- Expansion is adiabatic, energy comes from change in internal kinetic energy of air molecules
- Parcel temp decreases to supply energy for work done in expansion. Total energy of sys unchanged
Adiabatic lapse rate
Rate temp of a parcel of air will decrease as it moves upward
Adiabatic vertical displacement, temp decreases at a rate
Parcel of air will decrease at a rate of 10 deg C per km
Stability of vertical air motions
Change in Temp with height of air parcel independent of surrounding temp
Change of temp with height of surrounding air will determine if Fbwill push air parcel further
Latent heat
Energy transferred in a process without change of body temp via condensation or melting
