Meteorology Today, Ahrens Chap 6 Flashcards
What is the Adiabatic process relating to air parcels
a rising parcel of air expands and cools, while a sinking parcel is compressed and warms.
What is the dry adiabatic rate
10 C per 1000 meters
What does dry adiabatic rate mean
The rate a unsaturated parcel of air changes temperature adiabatically
What does Wet adiabatic rate mean
The rate a saturated parcel of air changes temperature adiabatically
What is the Wet Adiabatic Rate
6 C for 1000 meters
Why is wet adiabatic rate slower than Dry
As the parcel of air decreases in temperature, it eventually reaches 100% saturation, which causes water to condense, releasing latent heat that offsets the adiabatic rate
What is environmental lapse rate
rate at which the air temperature changes if we were to climb upward into the atmosphere
When is the atmosphere “Absolutely Stable”
When environmental lapse rate is less than the moist adiabatic rate. Air parcel cools faster than environment
when air in an absolutely stable atmosphere, what happens if it is forced to rise
Spreads out horizontally
What causes absolutely stable atmospheres to form
Surface Air cools, Air aloft is replaced by warmer Air, and Subsidence Inversions,
What are Subsidence Inversions
When a widespread layer of air descends. The layer is compressed and heated by the resulting increase in atmospheric pressure, and as a result the lapse rate of temperature is reduced. Usually occurs in high pressure systems
What type of environment does one with an inversion imply
Stable environment
What does an inversion cause
stratus
clouds, fog, haze, and pollutants are all kept close to the surface.
What does an environment in neutral stability mean
lapse rate is exactly equal to the dry adiabatic rate, rising or sinking unsaturated air will cool or warm at the same rate as the air around it. Air tends to resist vertical movement
What does it mean when an environment is unstable
environmental lapse rate is greater than dry adiabatic rate
