El Nino and La Nina for the Navy

Pressure Gradient

The change in pressure measured across distance is called a pressure gradient. The difference in pressure results in a net force that is directed from high to low pressure, and this net force is called the pressure gradient. Winds blow from higher to lower pressure due to the pressure gradient force.

animated gif showing pressure gradient

Image from the University of Illinois WW2010 Project

Interesting tidbit for movie buffs: Remember the scene from James Cameron's "Titanic" where Captain Smith decided to stay on the bridge and go down with the ship? As the ship sunk lower, it encountered greater pressure from the water as compared to the normal atmospheric pressure in the bridge. The difference in pressure grew as to overcome the strength and fastenings of the glass. The pressure gradient force works in a similar way, although not as dramatic! It pulls air from high pressure to low, creating winds which in turn push the water.