The weight of the column of air at any given point on the earth surface is called Atmospheric Pressure, and It is also Known as Barometric Pressure because Barometer records the atmospheric pressure
The Factors Influence
With an increase in the altitude, the length of the column of the overlying air on the surface of the earth decreases and hence the weight or the pressure exerted by the atmosphere also decreases.
When the atmospheric temperature increases, the air expands and loses density and similarly when the temperature decreases the air becomes denser and naturally a.p increases.
Water Vapour is lighter than the dry air so,if the content of water vapor in the air is higher, The a.p would be lower and vice-versa.
4.Atmospheric Pressure and air currents:
When temperature increases in an area, the air becomes lighter nd rises up, as a result, a low pressure develops there and to fill up the void and neutralize that low pressure, Cooler air descends in that area.