Diffraction phenomena / Interference

Especially around mid-level clouds, a colorful corona forms around the sun. Water droplets play a predominant role in the formation, bending the light into concentric rings.

The pollen corona is formed by light diffraction on the pollen grains. Especially, the pollen of spruce and pine can stay in the air for a long time due to air sacs and sometimes be carried over 100 km by light winds.

This diffuse brownish to reddish ring is formed when sunlight is diffracted by the countless dust particles in the atmosphere. The radius of the ring varies greatly with particle size.

A glory is the name for colored rings around the head of the observer's shadow, when it falls on clouds or a fog wall. The often greatly enlarged shadow projected onto the cloud cover in the center of the glory is the Brocken specter.

When deposits of pollen or algae are present on a water surface, colorful coronas can form in the reflected sunlight.

When thin clouds pass in front of the sun, the edges often begin to iridesce with color. The cause of the bright colors is the diffraction of sunlight by the small water droplets in the cloud.  

When particularly low temperatures below -85°C prevail in the stratosphere, shimmering nacreous clouds can form.