Chapter 7 - Humidity Flashcards
What does a hygrometer do?
Measures humidity
What is a psychrometer?
A type of hygrometer that uses a dry bulb thermometer and wet bulb thermometer.
How can you work out cloud base from a psychrometer?
For every 1 degC of deviation between the thermometers multiply by 400.
400ft per degC.
What is latent heat?
The heat released or absorbed by a body during a state change.
What is sublimation?
The state change from solid to gas.
What is deposition?
The state change from gas to solid.
What releases more latent heat condensation or freezing?
Condensation.
What is saturated vapour pressure?
The vapour pressure when the amount of evaporation and condensation is equal.
What is absolute humidity?
The mass of water (in grams) per unit volume of air (m3).
g/m3
What is relative humidity?
The percentage of how much water is in a parcel of air compared with the amount there would be at saturated vapour pressure (how much there could be).
What is the mixing ratio?
The ratio of mass of water vapour mixed in with a mass of air. kg/kg.
What happens to mixing ratio as atmospheric pressure decreases?
It increases
What is saturated mixing ratio?
The maximum mixing ratio when air is saturated
What is dew point?
The temperature at which water vapour in air starts to condense.
How is cloud base calculated if outside air temperature and dew point are known?
(OAT - DP) x 400 = cloud base
