Changes to Air ParcelsPrecipitation Presentation

Definitions

• Lifting condensation level: the altitude where the parcel of air has reached saturation and cloud formation begins

• Adiabatic: a process where the parcel temperature changes due to an expansion or compression

Environmental lapse rate• The environmental lapse rate is the actual decrease in

temperature with an increase in altitude through the troposphere. 

Dry adiabatic lapse rate• The rate of expansion cooling for dry air is very close to

10_C/km • dry adiabatic lapse rate (DALR).

Wet adiabatic lapse rate• moist adiabatic lapse rate (MALR)• increasing altitude = 0.6C per 100 meters • greater the amount of vapour = smaller the adiabatic lapse

rate.

Dew Point Temperature• The dew point is a measure of the humidity content in the

air. • The temperature at which condensation starts occurring is

what we call the dew point.• The temperature the dew point is in direct relation to the

humidity

Sources

• http://www.atmos.ucla.edu/~fovell/AS3downloads/lapse_rates.pdf

• http://www.weatheroffice.gc.ca/mainmenu/faq_e.html#weather3