Meteorology
In weather forecasting the term "decoupling" usually refers to boundary layer decoupling of atmospheric layers over land at night. During the day when the sun shines and warms the land, air at the surface of the earth is heated and rises. This rising air mixes the atmosphere near the earth. At night this process stops and air near the surface cools as the land loses heat by radiating in the infrared. If winds are light, the air near the surface of the earth can become colder than the air above, and 'decouple' from the air above it. When this occurs the air near the surface can become much colder than when decoupling (and better mixing of air layers) does not occur.
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