12 terms

11. Adiabatic Process

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adiabatic
-the term from prcosses in which no heat energy is added or removed, but temp changes
-as a parcel of air rises or falls in the atmosphere it undergoes change in temp, pressure, and volume
rate of adiabatic change
-the rate at which air temp change as it rises and falls thru the atmosphere
what does this rate of change depend on?
-varies with humidity condition of the air
dry (unsaturated) vs. wet (saturated)
Dry Adiabatic Rate: (DAR or DALR)
-when air is unsaturated; air temp>dew point temp; RH<100%
- it's a constant rate of 1°C/100 m
or 10°C/1000 m
- rising air = cools at 1°C/100 m
- falling air = warms at 1°C/100 m
Wet or Saturated Adiabatic Rate: (SAR or SALR)
-when air temp is saturated; air temp=d.p. temp; RH=100%
-it's is not a constant rate, but variable: 0.5°-0.9°C/100m or 5°-9°C/1000m
-condensation releases latent heat thus slowing the rate of cooling (or warming)
What does SAR depend on?
-the moisture content of the air
-the more water vapor condensing to liquid there is in the air, the slower the rate of decline (closer to 5°C/1000m
about warm air, its density, it's volume changes,
-less dense (lighter)
-rises and expands (bc it comes under less pressure and rises in the atmosphere)
what happens to molecular action and temp with warm air (air expands)
- molecular action (kinetic energy) decreases and thus temp decreases
about cold air, its density, it's volume changes,
-more dense (heavier)
-sinks and compresses (bc it comes under more and more pressure)
what happens to molecular action and temp with cold air (air compresses)
-molecular action (kinetic energy) increases and temp increases
adiabatic temp change
-changing temp without adding or subtracting heat
result of compressing air or allowing allowing to expand
-rising air expands and cools
-sinking air is compressed and warms