Double Delight: Two Optical Phenomena in One Frame
Photographer: Adeel ShafiqSummary Author: Adeel ShafiqShown above is a portion of a 22-degree solar halo, at right, and the iridescent colors associated with a Boeing 777 (Singapore Airlines) flying at 34,000 ft (10,362 m), at left. This photo was captured from Lahore, Pakistan on June 7, 2024, a day of fair weather with just a few high clouds visible. I was lucky enough to catch the halo and iridescent contrails in the same frame!
22-degree-solar halos occur when sunlight passes through the hexagonal ice crystals that compose cirrus type clouds. The resulting circular ring of light seen around the Sun has a radius of 22 degrees. The myriad ice crystals act as prisms, refracting and dispersing the sunlight into its individual colors. Aircraft contrails have two sources. The major source is water droplets condensed from the water vapor generated by the jet engines -- combustion of aviation fuel produces water vapor, carbon dioxide and traces of NOx. The second source is the water vapor already in the air that condenses as air flows over the fuselage and wings. Air passing over the top of airplane wings or the convex shape of the fuselage travels faster, expands and cools. Iridescent colors are produced by the multitude of individual water droplets diffracting sunlight. Note that when the droplets are similar in size, they tend to diffract their light in the same direction, so the iridescent colors become more obvious to us.
Lahore, Pakistan Coordinates: 31.542451 74.417816
Related Links:Solar Halo, Contrails and Feathery ShadowsAdeel's Facebook Website