Consider the following statements on ‘Fog’: 1. Fog is simply a cloud

Consider the following statements on ‘Fog’:

  • 1. Fog is simply a cloud that forms close to the ground.
  • 2. Radiation fog is associated with radiation cooling of the land at night.
  • 3. Advection fog forms when moisture is blown over a cold surface and is chilled by contact.

Which of the statements given above are correct ?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question was previously asked in
UPSC CDS-2 – 2023
All three statements given about fog are correct.
Fog is a meteorological phenomenon that reduces visibility, caused by tiny water droplets suspended in the air near the ground.
Statement 1 is correct: Fog is essentially a stratus cloud that forms at or very near the Earth’s surface. The physical process is the same as cloud formation, but the location is different. Statement 2 is correct: Radiation fog forms under clear skies, when the ground loses heat rapidly through radiation, cooling the layer of air immediately above it below its dew point. This cooling leads to condensation and fog formation. Statement 3 is correct: Advection fog forms when warm, moist air moves horizontally over a cooler surface (land or water). As the warm air passes over the cold surface, it is cooled from below, causing the water vapor to condense and form fog.