Gravity waves (w-842-32)

In gallery: Photos of the month (2006)
Related photos: Clouds Various cloud forms

An early morning flight over the British isles shows gravity waves in a layer of stratus or fog. The wave crests are illuminated by the grazing light of the low sun. The waves occur due to a disturbance in the flow of two layers of air with different densities: a colder, denser layer of fog with clear air above. Here the disturbance is a small mountain range, and the fog is seen spilling into a valley between the mountaintops.

Photographed on December 19 with a Nikon FE camera, on Fujichrome Provia 100F film.