Humidity is a measure of the amount of water vapor in the
air.
it can be expressed in several ways.
"Specific humidity" is the mass of water vapor
per unit mass of combined dry air and water vapor, generally
expressed in grams per kilogram. The specific humidity of
an air parcel does not change with temperature.
"Absolute humidity" is the density of water vapor,
expressed as grams per cubic meter of air.
"Relative humidity" is discussed below. Related
terms are "saturation," which describes the condition
where water vapor is at a maximum concentration for the air
temperature (warm air can hold more moisture than cold);
"dew point temperature," the temperature at which
saturation occurs if air is cooled at constant pressure without
addition or removal of water vapor; and
"vapor pressure," which in meteorology is that
part of the total atmospheric pressure due to water vapor
content.
[Reference:
Arctic Climatography and Meteorology
http://nsidc.org/arcticmet/factors/humidity.html ]
What is the Ideal Humidity Range?
Humidity should be between 50-60% for Actual
and around 70-80% relative humidity.
How can I measure humidity within my Crabitat?