Tuesday afternoon, 6 November 2007, an unusual solar halo was observed in the skies above Lubbock.
Haloes are bright, often colorful arcs, spots, or rings seen in high cirrus clouds composed of ice. Haloes are formed by reflection and refraction of solar or lunar light through ice crystals, and occur frequently worldwide. Although haloes visible around the sun and the moon are a common occurrence, under certain conditions, halo displays can become particularly complex.
As high clouds streamed above the South Plains of west Texas Tuesday afternoon, a rather elaborate halo display was visible from Lubbock (and likely other South Plains communities) around 1:00 PM. In addition to the common circular 22 degree halo around the sun, a rarely seen bright ring was visible encircling the entire sky at the solar elevation. Known as a perhelic circle, this horizontal bright band of white light around the sky appears to encircle an observer, but is rarely seen due to the typical variability of clouds and their ice crystals throughout the entire sky.
Tuesday’s halo also was “circumscribed” above by a very colorful upper tangent arc. For more information on atmospheric optics CLICK HERE.