Walker Circulation:  A circulation cell in the equatorial atmosphere over the Indian Ocean (and Pacific).  There are
longitudinal cells where, on one side fo the ocean convection and the associated release of latent heat in the air above
lifts isobaric surfaces upward in the troposphere and creates a high in that region.   The lack or lesser degree of the same
process on the other side of the ocean results in lower pressure there.  In this way a longitudinal pressure gradient is established
which, being at the equator, cannot be balanced by the Coriolis force.  A direct zonal circulation is driven in the equatorial
plane with countervailing winds at the surface and in the upper troposphere with rising and sinking branches on the appropriate
sides of the ocean.  In the Indian Ocean air sinks over the cold waters off the Somali coast and a low-level acceleration
from west to east along the equator in the lower atmosphere.

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Walker Circulation: