Contrail and Shadow Above Jericoacoara, Brazil
December 11, 2007
The above photo shows a jet condensation trail (contrail) and its shadow above Jericoacoara, Brazil. The contrail points toward the Sun -- a required condition for its shadow to be observed. A contrail always produces a shadow, but we can only see it if we're positioned in such a way that the trail is aimed at the Sun. Jericoacoara is a popular Brazilian beach located in the state of Ceara.
Contrails (or vapor trails) are produced by the water vapor from jet exhaust condensing into a line of ice crystals in relatively humid upper-level atmosphere. Given a slight breeze and high enough humidity, contrails can form into cirrus clouds.
Photo taken on July 16, 2007.