Cloud Corona Above Bibliotheca Alexandrina, Egypt
February 05, 2007
On the morning of November 6, 2006, clouds of various altitudes, including impressive altocumulus patterns, were drifting across the sky in Alexandria, Egypt. I was performing an observing session in the Plaza of the Bibliotheca Alexandrina, Egypt's newly revived monument and noticed this magnifient irisation (cloud corona), which occurred at about 10:30 local Egyptian time (EET). As is the case for all coronas, the cloud corona is a diffraction phenomenon resulting from the interference of sunlight (or moonlight) about water droplets. See also the Earth Science Picture of the Day for January 3, 2006.