Two high-sun Parry arcs

We tend to think of upper Parry arcs the way we see them at low sun. Two observations from the past months, however, show what they look like when the sun is high up in the sky.

In the above image, we can see an almost straight-looking Parry arc photographed by Faber McMullen at 69° sun altitude. The image was taken in Navasota, Texas, on 8 May 2008. The Parry arc was accompanied by a circumscribed halo, and a parhelic circle that is faintly present in the pictures, too ( 1 ). He also made a simulation with Les Cowley’s and Michael Schroeder’s HaloSim, which helps to interpret the photo ( 2 ).

The other observation comes from Holesov, Czech Republic. Patrik Trncak photographed a short-lived Parry arc at 61° sun altitude on 19 June ( 3 ). The circumstances were similar. The cirrus clouds produced a circumscribed halo and a full parhelic circle besides the Parry arc.