Friday
May 6, 2016

Posted by Sandra on Friday, June 8, 2012 at 2:14pm.

Assume that a parcel of air is forced to rise up and over a 6000-foot-high mountain. The initial temperature of the parcel at sea level is 76.5°F, and the lifting condensation level (LCL) of the parcel is 3000 feet. The DAR is 5.5°F/1000’ and the SAR is 3.3°F/1000’. Assume that condensation begins at 100% relative humidity and that no evaporation takes place as the parcel descends. Indicate calculated temperatures to one decimal point.

1. Calculate the temperature of the parcel at the following elevations as it rises up the windward side of the mountain:

(a) 1000’_______°F
(b) 3000’ ______ °F
(c) 6000’ ______ °F

2. (a) After the parcel of air has descended down the lee side of the mountain to sea level, what is the temperature of the parcel?
________________________ °F

(b) Why is the parcel now warmer than it was at sea level on the windward side (what is the source of the heat energy)?

3. (a) On the windward side of the mountain, is the relative humidity of the parcel increasing or decreasing as it rises from sea level to 3000 feet?

(b) Why?

4. (a) On the lee side of the mountain, is the relative humidity of the parcel increasing or decreasing as it descends from 6000 feet to sea level?

(b) Why?