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 An Introduction to Walker-type Circulation Cells
(for the beginner)



Kara Sterling
PHYS 645
University of Alaska Fairbanks





Introduction


    Walker-type circulation cells in the atmosphere are thermally direct, ageostrophic,  circulations. The term thermally direct is used because the circulation consists of warm air rising and cool air sinking.  The exsistence of Walker-type circulations is largely confined to the tropics where coriolis forces are small, and ageosptrophic, or irrotational, flows can occur. These overturning circulations are large scale and can be associated with global climate variations.  Hence, understanding Walker-type circulations is important for predicting future climate changes.
    The nomenclature, Walker-type, is young in the field of atmospheric sciences and is used to depict circulations which are similar to the Walker Cell (i.e. a thermally direct cell).  
However, Walker-type is generally used to refer to east-west thermally direct atmospheric circulation cells, whereas north-south circulations are generally combined into a Mean Meridional Circulation (MMC) or Hadley Cell.


© Kara Sterling, 2003
send questions or comments to ftkas2@uaf.edu
last updated 12/10/03

Introduction
Dynamics
Examples
Observations
Summary
References