Presumption of the wind velocity using the funnel cloud picture of Tsukuba tornado

Abstract

Tsukuba tornado occurred 6 May 2012 was simulataneously filmed by many
pepople at various locations. We suggest the scheme estimating the
maximum tangential velocity and the core radius of the Tsukuba tonrado
from its figure filmed. The velocity and pressure fields of the tornado
in upper layer was adapted from those of Rankine vortex in our scheme.
The result showed that the maximum tangential velocity could be
estimated properly. The evaluation of the relationship between the core
radius of tornado and the radius of debris, however, was required more.