Marine Forecasting Course

30 Minutes

Ismail Gultepe (Environment Canada)

Fog in the Marine Environment

Published: 11 December 2013

Marine fog formation, development, and dissipation depend on many important physical, chemical, radiative, dynamical, and thermodynamical processes as well surface characteristics of the location in the ocean-land boundary system. Marine fog can be either warm fog or cold fog depend on temperature (T); if T is less than or equal to zero in the air, fog is called as freezing fog. The main reason of the fog formation is usually due to warm and moisture air advection over the cold ocean surface or over the radiatively cooled land surface. Ts-Td (ocean surface T and air dew point T) difference of about 2°C is usually used for a limit for fog formation. It is also possible that local marine environment can enhance or weaken the fog intensity because of vegetation, surface height, and sea breezes. Fog over the marine environments is usually dissipates at noon because of radiative heating and mixing due to turbulence with higher dry air. The intensity of fog is the function of liquid water content (LWC) and droplet number concentration (Nd) of the particles in the air mass. Increasing LWC and Nd result in visibility down to 10s of meters. In this presentation, marine fog observations using surface instruments and remote sensing platforms, and as well as its forecasting based on numerical models will be discussed and its effect on aviation, marine environment, transportation, and vegetation will be summarized.

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Filed under Keywords:

Sea, fog, liquid water content, instruments