Climate MVP's

There are certain variables that are of particular importance in a GCM. They are predicted at each model time step, and are used to calculate other important variables (such as amount of rainfall and fractional cloud coverage):

1. Three-dimensional wind
   The wind can be broken into three parts:
   - an east-west component
   - a north-south component
   - a vertical component
   
   
2. Temperature
   
   
3. Moisture
   This is usually expressed as specific humidity.
   
   

4. Geopotential
   Geopotential is the potential energy of the air, and it is defined as the work that must be done against gravity to raise a mass of 1 kg from sea level to a given height. It is calculated as the height of a layer of air (in meters) multiplied by the gravitational constant (9.8 m/s**2). A column of air that is warm will extend higher than a cold column of air because warm air expands. Therefore, geopotential increases with the temperature of the column. Since atmospheric pressure decreases with height, geopotential increases with decreasing pressure.

How do these variables affect the climate?

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