Nacreous Clouds

nacreous clouds

[′nā·krē·əs ′klau̇dz]
(meteorology)
Clouds of unknown composition, whose form resembles that of cirrus or altocumulus lenticularis, and which show very strong irisation similar to that of mother-of-pearl, especially when the sun is several degrees below the horizon; they occur at heights of about 12 or 18 miles (20 or 30 kilometers). Also known as mother-of-pearl clouds.

Nacreous Clouds

 

thin, translucent clouds that occur at high elevations (about 22–30 km). They are observed rather infrequently, usually at latitudes of 55°-60° just before sunrise or just after sunset (against the daytime background of diffused light they are invisible).

References in periodicals archive ?
Meteorological officer Renae Baker captured spectacular images of the nacreous clouds, on July 25.