Standard Article

Global Circulation

Hydrological Processes

  1. Gerald R. North1,
  2. Samuel Shen2

Published Online: 15 SEP 2006

DOI: 10.1002/9780470057339.vag019

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

North, G. R. and Shen, S. 2006. Global Circulation. Encyclopedia of Environmetrics. 2.

Author Information

  1. 1

    Texas A & M University, TX, USA

  2. 2

    University of Alberta, Canada

Publication History

  1. Published Online: 15 SEP 2006


The shape of the earth is very nearly spherical with radius approximately 6400 km. The depth of the oceans averages about 4 km and about two-thirds of the mass of the atmosphere lies within 10 km of sea level. This means that the atmosphere/ocean or the geophysical fluid system is only a very thin film of material moving and often swirling about the surface. The geophysical fluids are differentially heated by the sun, the tropical regions receiving much more solar heating than the polar latitudes. This differential heating, which takes place mostly through heating the earth's surface, sets up air currents, which overturn the fluid and redistribute the heating toward the poles. The earth also rotates about an axis with a fixed orientation in space. This rotation causes apparent forces on the geophysical fluid elements, deflecting them and leading to the formation of circulation patterns. The movements of the fluid media covering the planet form the complex of motions we call the global circulation, which is the main subject of this article.