Radiation fog and advection fog
Topic: Water in the Atmosphere: Humidity, Condensation, Clouds and Precipitation · NCERT: Beyond NCERT
Meaning
These are two kinds of fog, named after how the air cools. Radiation fog forms on clear, calm nights. The ground loses its heat to the sky and chills the air just above it to its dew point. Advection fog forms when warm, moist air moves sideways over a cold surface, such as a cold ocean current, and cools from below. "Advection" means sideways movement of air. Radiation fog is a land fog that often clears as the Sun warms the ground. Advection fog is often a coastal fog and can last a long time.
Example
The dense winter fog of the Indo-Gangetic plain is radiation fog. Advection fog is common on the Grand Banks of Newfoundland, where Gulf Stream air passes over the cold Labrador Current. It is also common at San Francisco, over the cold California Current. On the Atacama coast of Chile, people collect fog water, called "camanchaca", with nets.