Condensation Trail and Shadow

January 17, 2006


Provided by: Rick Stankiewicz
Summary authors & editors: Rick Stankiewicz

Above southern Ontario on October 17, 2005, I was treated to a superb view of a condensation trail (contrail) and its shadow. It was just before local sunset (within an hour), so the angle of the Sun was nice and low, and the high cirrus clouds made a perfect projection screen for the “shadow” of the cloud-like contrail of a jet aircraft. What's interesting about this shadow is that you can see that's not a simple break in the clouds because the shape of the contrail matches very closely with that of the shadow. Note the odd bulges and irregularities of their outlines. In this instance, the shadow was about 2 ½ times the length of the contrail. When the angle of the Sun is too low the shadow gets stretched out and it becomes difficult to discern the shape of the matching contrail. This particular shadow lasted for almost 20 minutes.

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