Kelvin-Helmholtz Contrail Above Norfolk, Virginia

March 02, 2005


Provided by: John A. Adam, Old Dominion University
Summary authors & editors: John A. Adam

The above photo showing a Kelvin-Helmholtz contrail was taken in the afternoon of a spring day in 2003, from Norfolk, VA. Kelvin and Helmholtz contributed significant understanding to the effects of shear flow in parallel streams of fluid. This instability, as it is called, is responsible for many of the billow clouds that are seen in the sky: several parallel ripples or bands of cloud with an almost uniform spacing between them are common manifestations of this phenomenon. They can also be associated with clear-air turbulence. In this particular case, a fairly well-defined set of "breaking waves," associated with a condensation trail or contrail (viewed nearly sideways on), was produced by vertical wind shear -- a significant difference in wind speed across the vertical thickness of the contrail. See also the Earth Science Picture of the Day for January 17, 2005.

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