By tracking cloud features in the photographs, they were able to determine wind speeds.
From the time these low cloud features appear in the sky, one can expect a sudden increase in the wind in less than 15 minutes.
The system as it was initially conceived involved pattern matching of cloud features with a development and decay model.
They differ from shelf clouds by being completely detached from other cloud features.
In the 1990s, the number of the observed bright cloud features grew considerably partly because new high resolution imaging techniques became available.
Unlike the north pole, the south pole does not show any hexagonal cloud feature.
This reveals cloud features in Jupiter's main atmosphere.
When Voyager 2 flew by Uranus in 1986, it observed a total of ten cloud features across the entire planet.
However in 1990s the number of the observed bright cloud features grew considerably.
The above image is a color composite made from short exposures, showing the disk of Uranus with some cloud features.