# Notes on Pressure Gradient Force

by Joe Archive on May 31, 2013

Based on MetEd unit

**Pressure Gradient Force**

The pressure gradient force is not a “force” exactly, but instead is a pressure-related acceleration caused by differences in pressure within a fluid mass, expressed as a force per unit mass. It is directed from higher toward lower pressure. It has both vertical and horizontal components, although in the atmosphere the vertical component is approximately balanced by gravity. Horizontally, the pressure gradient force is perpendicular to isobars on a horizontal surface. The pressure-related acceleration causes the wind, the transport of the fluid mass in the atmosphere. The strength of the acceleration is proportional to the gradient of pressure (pressure difference over a given distance), therefore the greater the pressure gradient, the greater the acceleration and the wind it can produce.

PGF = (1/rho)(Delta P/D)

PGF = u/T

DeltaP = PGF *rho*D = 10.3*1.29*100000 = 1328700/10000

PGF = 1/1.29 * 2000/222000

v = PGF*t = 70m/s

*Related*