What are specific humidity and vapor pressure? Are they “good” measures of moisture content in the atmosphere?
Specific humidity (q) is defined as the mass of water vapor divided by the mass of all of the air. Its units are g/kg and it is a “good” measure of moisture content in that the bigger the number of grams, the more water there is in the atmosphere. Vapor pressure is defined as the pressure that is exerted by the water vapor alone. Its units are millibars (mb) and it is also a good measure of moisture content. Both quantities have actual values and saturation values. The saturation values are found in “look-up” tables or are read off of graphs. Actual values can be measured with instruments or calculated if you have relative humidity (RH). 4. What is relative humidity (RH)? How does it change over the course of the day? Is it a “good” measure of moisture content in the atmosphere? Relative humidity is the amount of water vapor relative to the maximum amount of water vapor possible at a given temperature. In other words, it is the % of water vapor present to the amount it would contain if
