This photograph taken from about 320 kilometers (200 miles) above
the Earth shows a band of cirrus clouds produced by a westerly
jet stream that stretches across the Red Sea from Sudan to Saudi
Arabia. The contained uniformity of the cloud formation reflects
the narrow track of the jet stream moving from left to right across
the frame. The shuttle photo shows that the cloud band comprises
a series of distinct and precisely spaced roll clouds. These are
created by a rolling motion in the upper level air current. (Courtesy
LPI/NASA)