The force exerted on the surface by the column of air above it is called atmospheric pressure or air pressure. It is measured by means of an instrument called barometer.
Wind is an air movement having both direction and speed. Depending on the cause of the winds, they can blow in many directions.The Easterly winds blow from east to west whereas the westerly winds blow from west to east.
Humidity is the amount of water vapour present in air. Absolute Humidity is the weight of actual amount of water vapour present in unit volume of air.Relative Humidity is the Ratio of water vapour in air at a particular temp. to total amount of water vapour required to saturate the same air at same temperature. It is expressed in %Specific Humidity is the Weight of water vapour present in per unit weight of air. It is not affected by change in pressure or temperature.
In urban and industrial areas smoke provides plenty of nuclei which helps in the formation of fog and mist. Smog is a condition when fog is mixed with smoke.
Warm ocean currents raise the temperature in cold areas while the cold currents decrease the temperature in warm ocean areas.The Labrador current which is a cold current, lowers the temperature near the north-east coast of North America.
EXAMIANS