GEOG 1010 Lecture Notes - Lecture 5: Pressure-Gradient Force, Pressure Gradient, Atmospheric Pressure
Document Summary
The frequency of hurricane has been increasing lately. Hurricane is classified by the speed of wind. As soon as wind speed increases above 110 it could be classified as a hurricane. Atmospheric pressure (or air pressure) is the force produced by the weight of a column of air above a unit area of surface. Pressure normally ranges from 1050 mb ( high pressure ) to 950 (low pressure ) mb (or 105 to 95 kpa). The lowest pressures occur at the centre of tropical storms. The record low is 870 mb (87 kpas). The low pressure is associated with bad weather. Wind - horizontal motion across the earth"s surface - is created by gradients in air pressure (or air density ). The greater the pressure difference or gradient, the stronger the winds. We named the wind after its point of origin. Any parcel of air near the surface is subjected to the following forces: a.
