Ranchi, Jharkhand 02 January 2015 :: On the very next day of the new year Dense Fog covered city, by which people faced poor visibility. Although it was raining since the morning but suddenly in evening the whole city get covered with dense fog. Due to bad wheather the roads were also seen vaccant.
Fog is a collection of liquid water droplets or ice crystals suspended in the air at or near the Earth’s surface.Fog can be considered a type of low-lying cloud, and is heavily influenced by nearby bodies of water, topography, wind conditions, and even human activities. In turn, fog has affected many human activities, such as shipping and transport, warfare, and culture.
The term “fog” is typically distinguished from the more generic term “cloud” in that fog is low-lying, and the moisture in the fog is often generated locally (such as from a nearby body of water, like a lake or the ocean, or from nearby moist ground or marshes).
By definition, fog reduces visibility to less than 1 kilometre (0.62 mi), whereas mist causes lesser impairment of visibility.
Fog forms when the difference between air temperature and dew point is generally less than 2.5 °C or 4 °F.
Fog begins to form when water vapor condenses into tiny liquid water droplets suspended in the air. The main ways water vapor is added to the air: wind convergence into areas of upward motion; precipitation or virga falling from above; daytime heating evaporating water from the surface of oceans, water bodies, or wet land; transpiration from plants; cool or dry air moving over warmer water; and lifting air over mountains. Water vapor normally begins to condense on condensation nuclei such as dust, ice, and salt in order to form clouds. Fog, like its elevated cousin stratus, is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass.