Heard Island's vortex street

Heard Island is a remote Australian volcano in the Southern Ocean, about 4,000 km south-west of Western Australia and 1,000 km north of Antarctica.

What the satellite saw

Dark round holes in a white cloud deck, in a line north of Heard Island's white peak
Heard Island, 3 May 2016: only Mawson Peak shows above the cloud; the eddies punch holes in the deck downwind. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response ("Going with the Flow"). Public domain.
The wake behind Heard Island as Wind Tunnel draws it, the NASA photo of the real one laid over the lower right corner
Heard Island in Wind Tunnel with Satellite photo on: the simulation, made in your browser, with NASA's photo in the corner.

NASA's Aqua satellite photographed it with MODIS on 3 May 2016 (Earth Observatory, "Going with the Flow"). Only the tip of Mawson Peak shows above the cloud deck. Strong southerly winds pushed the eddies north, and each one opened a round, dark hole in the white.

Why Heard Island

Height. Mawson Peak rises to 2,745 m, enough, NASA writes, to stir up several cloud vortices.

A thick, low deck. Marine stratocumulus covers the sea almost everywhere around it; the eddies open dark holes in it as they pass.

Isolation. There is nothing else for hundreds of kilometres.

Make it in Wind Tunnel

  1. Open the link below: the wind blows from the south, 180°, as on the day of the photo. Pressing Heard Island under Island starts it from the west, the prevailing wind there.
  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. Choose 4K and 20 seconds under Save, and press MP4 once the street has formed.

Open Heard Island in Wind Tunnel