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October 22, 2010

Speaker: Dr. Bill Langford, Department of Mathematics and Statistics, University of Guelph

Title: Poleward Expansion of Hadley Cells

Abstract: A mathematical model has been constructed for the study of convection in a rotating spherical shell of fluid, with radial gravity and a pole-to-equator temperature gradient on the inner boundary. The model fluid satisfies the Navier-Stokes Boussinesq equations. Depending on the strength of the temperature gradient, convection cells appear that are analogous to the Hadley, Ferrel and polar cells of the present day Earth's atmosphere. The model reproduces the trade winds, westerlies, jet streams and polar easterlies of today's Earth's climate. As the temperature gradient is decreased, the Hadley cells slow in their circulation velocity and expand poleward, as recently observed for Earth's climate. Eventually, for still smaller values of the temperature gradient, the Ferrel and polar cells disappear and the resulting circulation resembles that of the "greenhouse" palaeoclimate that dominated the Earth for much of geological time. This is joint work with Greg Lewis of UOIT.
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