2007-12-22 23:06:36 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Weather
Clear sky,light wind,presence of sufficient moisture in the air and ground inversion cause fog.In such conditions,radiation cooling occurs bringing down the air temperature below freezing point and causing condenstion which leads to fog formation.
2007-12-23 02:45:22 · answer #1 · answered by Arasan 7 · 0⤊ 1⤋
Fog
Fog forms when water vapours in the air, at the surface, begin to condense into liquid water. Fog normally occurs at a relative humidity of 100%. This can be achieved by either adding moisture to the air or dropping the ambient air temperature. Fog can form at lower humidities, and fog can sometimes not form with relative humidity at 100%. A reading of 100% relative humidity does not mean that the air can not hold any more moisture, but the air will then become supersaturated. Fog formation does require all of the elements that normal cloud formation requires with the most important being condensation nuclei. When the air is saturated, additional moisture tends to condense rather than staying in the air as vapor. Condensation nuclei must be present in the form of dust, aeresols, pollutants, etc. for the water to condense upon. When there are exceptional amounts of condensation nuclei present, especially hydroscopic (water seeking such as salt, see below) then the water vapor may condense below 100% relative humidity.
2007-12-23 01:07:45 · answer #2 · answered by An ESL Learner 7 · 0⤊ 1⤋
Fog is a cloud in contact with the ground. Fog differs from other clouds only in that fog touches the surface of the Earth. The same cloud that is not fog on lower ground may be fog where it contacts higher ground such as hilltops or mountain ridges. Fog is distinct from mist only in its density. Fog is defined as cloud which reduces visibility to less than 1 km, whereas mist is that which reduces visibility to less than 2 km
2007-12-23 00:00:21 · answer #3 · answered by Anonymous · 0⤊ 0⤋
When the dew point comes close to the outside temp or exceeds it the moisture that is in the air begins to condense and it forms fog. It is very much like your hot breath hitting the cold air in Winter when you exhale. Your breath appears like fog.
2007-12-22 23:21:18 · answer #4 · answered by justforfun_1811 3 · 0⤊ 1⤋
http://www.weatherquestions.com/What_causes_fog.htm
2007-12-22 23:22:19 · answer #5 · answered by Anonymous · 0⤊ 1⤋