→ 1. Advection Sea Fog

Advection sea fog occurs when coastal warm air masses produced over the land surface from radiational effects advects over the sea surface via nocturnal land breezes, The warm, moist air from the land moves over colder sea surfaces that will eventually cool the lowest part of the atmosphere, or boundary layer. Typical air temperatures of advected sea fogs are about 1° - 2° Celsius warmer than the sea surface temperature and contain wind speeds from 2 – 8 m/s. The consequential cooling of the lowest warm layer of the boundary layer cools to below the dew point temperature of the air mass, thus allowing for condensation to occur. A layer of condensed moisture, or fog, near the surface will form due to condensation of the moisture within the boundary layer. Advection sea fog events will generally happen during the night time to early morning hours when the atmosphere is most stable. This sea fog is also called radiation fog.


This diagram depicts the formation of advection sea fog. Warm, moist air is advected off the land surface in a stable layer. The warm air cools over the cold sea, allowing condensation to occur. The condensed water vapor in the atmosphere remains in the stable boundary layer producing the sea fog. Longwave radiative cooling above the stable boundary layer continuously keeps the lower atmosphere stable, allowing for sea fog formation.



Example: The hot city of Dubai lies next to the Persian Gulf and Arabian Sea intersection in the Middle East. The warm air advects off the coastline and cools over the sea surface, where condensation begins to form and produces sea fog.

Example: The hot city of Dubai lies next to the Persian Gulf and Arabian Sea intersection in the Middle East. The warm air advects off the coastline and cools over the sea surface, where condensation begins to form and produces advection sea fog.


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