For a couple of days now, sunsets and sunrises have been really picturesque with fiery reds, oranges and purples, and an oddly coloured sky even much after sunset (or before sunrise). This is caused by the early August eruption of three Alaskan stratovolcanoes: Kasatochi, Okmok and Cleveland ( 1 - 2 ). In the United States such volcanic sunsets had been observed several days before, but it seems that the aerosols in the stratosphere have reached Europe. As the fine volcanic ash and the aerosols of sulphur oxide spread ( 3 ), they scatter sunlight and cause these beautiful sunset colours. When taking a closer look at the coloured sky, fine structure can be observed, which is possible to see shortly before sunrise and after sunset, as well. These are the aerosol particles, structured delicately high up in the sky ( 4 ). To see the structure, click on the images below.
30 August 2008 - Vecsés, Hungary
The images below were taken on 21 August, and the structure that looks like and undulatus cloud or gravity wave, must have been caused by the tiny volcanic particles. The last image is unsharp-masked. You can view it in full size, too ( 6 ).