ENVIRSC 1A03 Lecture Notes - Lecture 7: Lifted Condensation Level, Fluid Parcel, Adiabatic Process
26 Apr 2015
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Document Summary
Expands and cools: sinking parcel of air. Dry adiabatic lapse rate no longer operates beyond that point: air cools at dalr, air becomes saturated ( condensation begins, visible cloud starts to form) , air cools at salr, parcel cooler than surrounding air. Atmospheric instability: for atmospheric stability, we compare environmental lapse rate to the saturation and dry adiabatic lapse rate, example, environmental lapse rate is 12 degrees celsius/ 1000m, dry adiabatic lapse rate is 10 degrees. Environmental lapse rate > dry adiabatic rate. Rising air parcel will continue to rise because warmer and less dense than air surrounding it. Slope of environmental lapse rate is steeper than dry adiabatic lapse rate and moist adiabatic lapse rate. When air parcel is warmer than air surrounding it there is an upward directed force called bouyant force. Warmer air parcel compared to surrounding the greater the bouyant force and more rapidly the air rises: creating an unstable atmosphere.
