Solar phenomena: Contrails intercept solar halo

A Weather & Radar user in Ireland captured a combination of phenomena on camera, one natural, one man-made.

In the image, sent in by user WJ Stapleton from Fairford, Gloucestershire, we see a solar halo expanding around the sun as a plane flies underneath.

The aircraft’s contrails cast shadows as the sunlight passes through the ice cloud for a stunning capture.

Let’s start with the halo captured around the sun. These halos are a visual phenomenon caused by suspended ice crystals in the air.

These can sometime be colourful but are most often seen as white light circles, arcs, and spots in the sky.

The result of refraction and reflection of sunlight through ice crystals in cirrus clouds in the sky, these halos also appear at night in the moonlight.

Secondly, we have contrails left behind by a passing aircraft. These too are a form of ice cloud formed as water vapour condenses around the dust particles, mainly soot, released by aeroplanes as they pass through the air.

There are different forms of contrail. The short-lived contrail, create short while lines and quickly vanish. The persistent (non-spreading) contrail form long white lines which remain in place long after the plane departs.

Finally, the persistent (spreading) contrail form in the same way as the non-spreading variant, but are denser in the sky above.

As these trails are simply ice clouds they have no impact on weather systems, or at all, other than simply scattering the sky creating paths behind flights overhead.