Abstract
On May 31, 2007, a waterspout occurred near Futtsu Coast, Chiba Prefecture. According to the Doppler radar observation at Yokosuka and the ground survey, the characteristics of the waterspout were revealed. The waterspout formed over the shear band at 17:28 JST, and the lifetime of the waterspout was about 7 minutes. The direction of the vortex rotation was anticyclonic and the vortex diameter was about 25 m near the surface. The tangential velocity was estimated to be approximately 20 m/s based on the images and vorticity had on the order of 100 s-1. The waterspout was almost stationary and the funnel diameter remained unchanged.
