17th Conference on Atmospheric and Oceanic Fluid Dynamics
15th Conference on Middle Atmosphere

JP1.20

Understanding Tornadoes and Microbursts

Essam A. Farag, SNC-Lavalin Inc., Montreal, QC, Canada

Tornadoes and microbursts are violent columns of air in the atmosphere. Meteorologists do not yet fully understand the mechanisms that develop them from a thunderstorm. This paper provides a clear understanding of such mechanisms. It is based on earlier experimental and theoretical investigations of confined vortex flows by the author. In these investigations, flow pattern observations and analytical solutions of the boundary-layer thickness and flow are obtained. Their results are applied to tornadoes and microbursts and prove that these natural phenomena are not the result of convective currents or descending cool air as commonly speculated. They are natural phenomena caused by swirls in the atmosphere. These swirls are created by wind shear. The presence of a cloud base under these conditions results into a confined swirling flow similar to that inside a vortex chamber. In other words, tornadoes and microbursts are the result of concentric boundary-layer flows. These flows are separated into reverse flow, core flow and mantles flow as demonstrated in this paper.

extended abstract  Extended Abstract (492K)

Joint Poster Session 1, Theory
Monday, 8 June 2009, 4:30 PM-6:00 PM, Stowe Room

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