in the Atmosphere
| Thought Questions on Humidity
(for class on Wed., Feb. 25)
| Dr. Dave Dempsey
Dept. of Geosciences
SFSU, Spring 2009
Which parcel has the most water vapor in it?
Tucson: 0.20 X 45 g = 9 g; San Francisco, 0.50 X 15 g = 7.5 g. Despite the higher relative humidity at San Francisco, there is much more water vapor present in Tucson. From Fig. 4.10, Tucson's dew point would be 9.5C or so. San Francisco's dew point would be 0C.
What would happen to the amount of water vapor in the Tucson parcel if it were cooled to the same temperature as the air in San Francisco? What would its relative humidity be then?
The amount of water vapor would remain the same, however the relative humidity would increase, since the new saturation mixing ratio would be 15 g. The relative humidity would increase from 20% to 9/15 X 100 = 60%.