Brazilian Greetings Contrail

July 08, 2009


Photographer: Mario Freitas, Universidade Tecnologica Federal do Parana 
Summary Author: Mario Freitas, Universidade Tecnologica Federal do Parana; Jim Foster

Condensation trails (contrails) are man-made cirrus type clouds, produced when cold, moist air condenses around small particles (aerosols) shed from jet exhausts. Though these clouds are thin and typically narrow, they nonetheless trap infrared radiation emitted from Earth. The aerosols reflect solar shortwave radiation to a lesser degree than they absorb longwave radiation. In spite of their effect on the radiation balance, contrails can be quite eye catching at times. This is especially so when they are purposely formed by skilled pilots who can expertly control their trajectories to draw figures or to write words and numbers. In the above photo, taken over Curitiba, Brazil, the mushroom-like clumping along the contrail edges is the result of atmospheric turbulence. In Portuguese, “Oi” is equivalent to “Hi” in English. Picture taken on May 24, 2009.

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