Types of Fog
Fog is classified according to the way it forms . Radiation fog also known as Ground fog is very common . it forms over fairly level surfaces on clear , calm humid nights . as surface cools by radiation the adjucent air is also cooled to it's dewpoint (which is the temperature at that air reaches a state where it can't hold any more water vapor) . radiation fog usually occurs in stable air associated with high pressure system .
Advection fog is caused when a low layer of warm , moist air moves over cooler surface . it is most common under cloudy skies along coastlines where air moves from the warm water to the cooler surface of land .
Upslope fog forms when moist , stable air forced up a sloping land mass . like advection fog , upslope fog occure under cloudy skies .
Precipitation _ induced fog may form when warm air or drizzle falls through a layer of cooler air near surface . evaporation from the falling precipitation saturates the cool air causing fog to form . this fog can be very dense and usually it does not clear until the rain moves out of the area .
Steam fog or Sea smoke occurs as cold , dry air moves over comparatively warmer water . it rises upward from the water surface and resembles rising sea smoke . it is composed entirely of water droplets that often freeze quickly and fall back into water as ice particles .
Note : radiation fog is stronger than advection fog . temperture diffrent between dewpoint and environment temperture for fog formation must be less than 2 degree of C(4 degree of F)