Formation of Fog Quiz

Causes of Evaporation Fog

• Evaporation fog forms when cold air passes over warmer water, causing moisture to evaporate and condense into fog.
• This phenomenon typically occurs in conditions where water temperatures are significantly higher than the air temperature.

Main Types of Fog

• Radiation Fog: Develops overnight when the ground loses heat rapidly, cooling the air near the surface.
• Advection Fog: Forms when warm, moist air moves over cooler surfaces causing condensation.
• Orographic Fog: Occurs when moist air is lifted over mountains or hills, leading to cooling and condensation.
• Evaporation Fog: Results from the mixing of cold air with warm, moist air over a body of water.

Causes of Radiation Fog

• Radiation fog is primarily caused by the loss of heat from the ground during clear, calm nights, allowing the air near the surface to cool below its dew point.

Fog Formation Over Mountains

• Orographic fog is formed when moist air is forced to rise over a mountain or hill, leading to cooling and moisture condensation.

Differences Between Evaporation Fog and Radiation Fog

• The key difference lies in their formation conditions: evaporation fog occurs due to moisture from warm water interacting with cooler air, while radiation fog arises from the cooling of ground surface air after sunset.

Factors Influencing Fog or Dew/Frost Formation

• The primary factor in determining whether fog or dew/frost forms in still air is the temperature gradient between the air and the surface; if air cools enough to its dew point, fog will form instead of dew or frost.

Effect of Light Wind on Radiation Fog

• A light wind of around 5 knots can disrupt the development of radiation fog by mixing the air layers, preventing the surface air from cooling effectively.

Primary Cause of Advection Fog

• Advection fog primarily arises when warm, moist air moves horizontally over a cooler surface, leading to condensation as the air temperature drops.

Longevity of Fog Types

• Advection fog is typically the longest-lasting fog type due to the continuous supply of warm, moist air coming in over cooler surfaces.

Primary Cause of Orographic Fog

• Orographic fog is mainly caused by the forced ascent of moist air as it encounters topographical features like mountains, leading to cooling and subsequent fog formation.

Test your knowledge on how fog forms and the different factors affecting visibility. Learn about the various types of fog formation including evaporative fog, radiation fog, advection fog, and orographic fog.