Which fog type is most likely to form in coastal areas or where there are temperature contrasts?

Which fog type is most likely to form in coastal areas or where there are temperature contrasts?

• A. Radiation fog
• B. Advection fog
• C. Upslope fog
• D. Frontal fog

Answer: (B)

Fog forms when air is cooled to its dew point, causing water vapor to condense. When warm, moist air moves horizontally over a cooler surface—such as sea water or cooler land—the air is cooled by contact with that surface to its dew point, and condensation creates fog. This horizontal transport of moist air over a surface with a different temperature is common in coastal areas, where the ocean provides abundant moisture and often a temperature contrast with the land or with air aloft. This makes advection of moist air over a cooler surface the most likely path to fog in those settings. Other fogs come from different processes: radiation fog forms from ground cooling on calm, clear nights inland; upslope fog forms as air rises and cools over terrain; frontal fog arises from moisture changes near weather fronts.

Fog forms when air is cooled to its dew point, causing water vapor to condense. When warm, moist air moves horizontally over a cooler surface—such as sea water or cooler land—the air is cooled by contact with that surface to its dew point, and condensation creates fog. This horizontal transport of moist air over a surface with a different temperature is common in coastal areas, where the ocean provides abundant moisture and often a temperature contrast with the land or with air aloft. This makes advection of moist air over a cooler surface the most likely path to fog in those settings. Other fogs come from different processes: radiation fog forms from ground cooling on calm, clear nights inland; upslope fog forms as air rises and cools over terrain; frontal fog arises from moisture changes near weather fronts.