Cloud iridescence opposite the sun

I already observed cloud iridescence opposite the sun several times (1 – 2). But until now I always could explain it by the appearance of a deformed glory. But on February 18, 2014, on Mt. Zugspitze, it was different. On the summit of that mountain at 2963 metres above sea level, some altocumulus clouds passed about 500 metres above me. While the shadow of the mountain and a faint glory showed up in a lower cumulus cloud, the colours in the foehn cloud were arranged in bands and seemed to be completely independent from the glory (more pictures here). Also in sunward direction, the altocumulus lenticularis showed similar colourful bands.

Deformed glories are caused by differences in the radii of the cloud droplets, which changes the diameter of the glory. When the droplets become smaller within a short distance, the radius increases, and if the observeer sees only a fragment of the glory, colours may appear distorted. I, however, never before noticed such colour bands in the area where a glory can appear.

Author: Claudia Hinz

„Glorydescent Clouds“

In the morning of March 1st, 2010, I made my second observation of „glorydescent clouds“ (here the first). These are fragments of a glory which change very much in diameter due to the different size of the droplets towards the rim of a short-lasting foehn cloud.
This makes the sequence of the colours look asymmetrically.
The stratocumulus lenticularis cloud did not even last for 5 minutes and caused a bright and very changeable iridescence or “glorydescence” during this short period of time. When the colours reached their maximum, up to 4 systems of rings were visible, with the 4th one appearing in the cloud behind the glory.
The pictures were taken at 8.05 CET / 8.06 CET / 8.07 CET.

Author: Claudia Hinz

A strange kind of glory

I have often seen glories which appeared to be elliptical (and not circular) or vertically disrupted. This was always caused by the projection onto an uneven cloud cover. But on November 18, 2007, I could observe a “vaulted” glory from Mt Wendelstein (1835m) in the Bavarian Alps. The strange glory appeared in an isolated stratocumulus cloud which adapted to the shape of a mountain. Its colours ended irregularly on its outer fringe like those of a glory around the sun which pass over to cloud iridescence. There is no circular shape recognizable in the colours outside the inner glory rings. The pictures are taken using a polarization filter and the contrast has been increased.

Another observation which might be related to mine, has been made on January 01, 2007 by Stefan Rubach on Mt Großer Arber.

Author: Claudia Hinz, Brannenburg, Germany