Graphic by: Yiqi Shao

The weight of the air above an object exerts a force per unit area upon that object and this force is called pressure. Variations in pressure lead to the development of winds, which in turn influence our daily weather. The purpose of this module is to introduce pressure, how it changes with height and the importance of high and low pressure systems. In addition, this module introduces the pressure gradient and Coriolis forces and their role in generating wind. Local wind systems such as land breezes and sea breezes will also be introduced. The Forces and Winds module has been organized into the following sections:

Last Update: 09/02/99
Introduces pressure, associated characteristics, and high and low pressure centers.

Pressure Gradient Force
A net force that is directed from high to low pressure.

Coriolis Force
The apparent deflection of objects due to the earth's rotation.

Geostrophic Wind
Winds that result from a balance of Coriolis and pressure gradient forces.

Gradient Wind
Winds that blow parallel to isobars, but are not geostrophic.

How friction near the surface affects geostrophic and gradient wind.

Boundary Layer Wind
More on how friction affects low level winds.

Sea Breezes
Atmospheric conditions that lead to the development of sea breezes.

Land Breezes
Atmospheric conditions that lead to the development of land breezes.

Those who contributed to the development of this module.

The navigation menu (left) for this module is called "Forces, Winds" and the menu items are arranged in a recommended sequence, beginning with this introduction. In addition, this entire web server is accessible in both "graphics" and "text"-based modes, a feature controlled from the blue "User Interface" menu (located beneath the black navigation menus). More information about the user interface options, the navigation system, or WW2010 in general is accessible from About This Server.

El Nino
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.