What is Radiation fog?

What is Radiation fog?

• A. It forms when the ground heats up rapidly at night.
• B. It forms when air above cools rapidly at night.
• C. Radiation fog forms when the ground cools rapidly at night, reaching the dew point and condensing water vapor.
• D. Radiation fog forms only over deserts.

Answer: (C)

Radiation fog forms when the ground loses heat rapidly at night due to radiative cooling. As the surface cools, the air right above it also chills to its dew point, and water vapor condenses into tiny droplets, creating fog at ground level. This typically happens on clear, calm nights with relatively high humidity, and it usually dissipates after sunrise as the ground heats up again. It’s driven by surface cooling, not by the ground heating, and it isn’t limited to deserts—it can form in many low-lying, humid areas under the right conditions.

Radiation fog forms when the ground loses heat rapidly at night due to radiative cooling. As the surface cools, the air right above it also chills to its dew point, and water vapor condenses into tiny droplets, creating fog at ground level. This typically happens on clear, calm nights with relatively high humidity, and it usually dissipates after sunrise as the ground heats up again. It’s driven by surface cooling, not by the ground heating, and it isn’t limited to deserts—it can form in many low-lying, humid areas under the right conditions.