Upon seeing a rainbow, we say,
זוכר הברית, ונאמן בבריתו, וקים במאמרו
...who remembers the covenant, is faithful in his covenant, and fulfills his word.
I recently witnessed a natural event that looked very much like a rainbow, but it was not a rainbow scientifically speaking. Although it was brightly colored, it was curved downward like a smile, it was high in the sky when the sun was not far from the horizon, and there were no rainclouds in sight (EDIT:) although it appeared in cirrus clouds.
Upon investigation it seems to have been a circumzenithal arc, caused by ice crystals in cirrus clouds. There are apparently lots of different phenomena of this type. This phenomenon can occur in Israel.
Since halachah was established at a time when atmospheric phenomena were not well understood by science, it made me wonder if it is halachically in the same category as a rainbow, so that the blessing would be זוכר הברית as above. If not, should a blessing be recited, and which one?