Rishiri's vortex street

Rishiri is a small, round volcanic island in the Sea of Japan, off the north-west coast of Hokkaido.

What the satellite saw

A chain of cloud eddies trailing from the small volcanic island of Rishiri, photographed from the Space Shuttle
Rishiri, 30 April 2001, from the Space Shuttle: the island at the bottom of the chain, the eddies stacked above it. NASA/JSC, astronaut photograph STS100-710-182, Space Shuttle STS-100. Public domain.
The wake behind Rishiri as Wind Tunnel draws it, the NASA photo of the real one laid over the lower right corner
Rishiri in Wind Tunnel with Satellite photo on: the simulation, made in your browser, with NASA's photo in the corner.

Astronauts on the Space Shuttle mission STS-100 photographed its vortex street on 30 April 2001 (NASA image STS100-710-182). The island is at the bottom of the chain; the eddies stack above it.

NASA's note on the photo: these eddies form when a stable atmosphere with low clouds flows past a fairly small obstacle that is taller than the cloud layer is deep.

Why Rishiri

Height. Mount Rishiri rises to 1,721 m from an island of about 183 square kilometres.

Shape. Nearly round, it is the closest thing in nature to the tunnel's cylinder.

Stable air. The cold Sea of Japan holds a shallow cloud deck under a lid of warmer air.

Make it in Wind Tunnel

  1. Open the link below, or press Rishiri under Island: the wind starts from 315°, north-west.
  2. Press Cloud under Look and Satellite under Colour: white cloud on a blue-grey sea, as the photo sees it.
  3. Turn on Satellite photo under Island to lay this photo over the corner of the frame, beside the flow.
  4. Then press Cylinder at the same Re and compare: the round island and the round post shed nearly the same street.

Open Rishiri in Wind Tunnel