Socotra's wake in the monsoon

Socotra lies in the Arabian Sea off the Horn of Africa. From June to September the south-west monsoon blows across it, hard and steady.

What the satellite saw

Socotra in the Arabian Sea with faint streaks of dust downwind of it
Socotra, 9 September 2006: the monsoon wake shows in dust, not cloud, as two faint streamers. NASA image created by Jesse Allen, Earth Observatory, using data provided by the MODIS Rapid Response team ("Dust Over the Gulf of Aden"). Public domain.
The wake behind Socotra as Wind Tunnel draws it, the NASA photo of the real one laid over the lower right corner
Socotra in Wind Tunnel with Satellite photo on: the simulation, made in your browser, with NASA's photo in the corner.

NASA has no photograph of a cloud street behind Socotra. Its Terra satellite saw the island's wake in dust instead, on 9 September 2006 (Earth Observatory, "Dust Over the Gulf of Aden"): two faint streamers running roughly side by side downwind, which NASA suggests the island's wake helped shape.

A wake can be drawn in anything the air carries. In the tunnel the dye does the same job.

Why Socotra

Height. The Hajhir mountains rise to about 1,500 m.

The monsoon. One of the steadiest strong winds on Earth while it lasts.

Little cloud. In the monsoon the air over Socotra is often too dry for a cloud deck, so its eddies go unseen unless dust or haze marks them.

Make it in Wind Tunnel

  1. Open the link below, or press Socotra under Island: the wind starts from 225°, south-west.
  2. Press Paper under Look to see the wake as lines of dye, as the dust drew 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 Socotra in Wind Tunnel