ABSTRACT
Organisations concerned with minimising the operational problems caused by fog need to be informed of the physical nature of the fog in order that realistic assessments of the feasibilities of proposed practical solutions can be assessed. The occurrence of fog is associated with meteorological conditions which are conducive to the cooling of air below its dew point. Radiation fog and smoke fog most commonly occur during anticyclonic spells and col situations when winds are light, while advection fog over coasts is usually associated with moist south-westerly airstreams. Fog is a hazard to transport by land, sea and air and costly adjustments such as automatic aids for aircraft and safety signalling for rail transport are needed. Meteorologists have investigated a number of objective fog forecasting techniques, but visibility remains probably the most difficult of all meteorological phenomena to forecast accurately.
