Night time cooling - radiation inversion

• During the night time hours, there is no SW heating the ground, so the ground cools rapidly

• hence, there is heat transfer by conduction from the warm air to the cold ground

• this heat transfer occurs in a shallow layer near the ground since air is a poor conductor

• a "radiation inversion" is formed: a shallow layer of air near the earth's surface where the temperature increases with height

• average radiation inversion depth is about 100m, but can vary from 10m - 1 km