To say our atmosphere is dynamic does not really do a very good job of explaining the complexity of those dynamics. Atmospheric pressure can be significantly different between one place and another. Atmospheric pressure can be quite different between the Earth’s surface and a few miles above our heads. We have to send instruments aloft, bundled to balloons, embedded in aircraft, or launched into space, in order to determine what is going on in our atmosphere.

The chapter deals primarily with pressure, how pressure is measured, describes what a pressure gradient is, how pressure gradients develop, and how pressure gradients and the Earth’s rotation influence both surface winds and winds miles above us.