Sunday, January 03, 2010

Iridescent Fireworks Smoke

Like everywhere around the world, New Years Day was also welcomed with fireworks around Mt. Wendelstein. It is always a special highlight to watch the fireworks from the top of the mountain at 1838 meters above sea level. In the Leitzach Valley, about 1000 meters lower, there was a fireworks display.
Even when watching it with the naked eye, the smoke and fog of the fireworks seemed to show iridescent colours. The photographs
(photo) show the iridescence more obviously. It was probably caused by the condensation nuclei from the fireworks smoke, on which small droplets condensated. As short time before an area of precipitation had passed, air humidity was still very high.
Additionally, the fireworks caused a thin layer of fog over almost the whole alpine foothills area (photo), and the big city of Munich with more than a million inhabitants, was covered by a thick layer of clouds (photo).

Similar things were reported by other observers. In Bochum, Peter Krämer observed that light graupel turned into snow during the fireworks, leaving about a centimetre of snow. On the weather radar it could be seen that a precipitation area formed right over the Ruhr area just after midnight.

Two years ago, thin fog with visibilities around 300 meters thickended after the New Years Fireworks, forming a dense layer of fog with visibilities which were less than 10 meters in some places.

Northwestern Germany Diamond Dust Sun Pillar

Diamond dust halos are normally observed in northern regions of Europe, or in the mountains where temperatures in winter often drop sufficiently for the formation of ice crystals near the ground.

On December 19, 2009, there were several reports of diamond dust from the lower parts of northwestern and western Germany, which formed widespread sun pillars.
With temperatures of about -14°C, I also witnessed an upper and lower sun pillar in Bochum, Germany.
The lower sun pillar was visible in front of trees and even the snow-covered ground, as the picture taken at about 9 hours CET shows with the sun hidden behind a sign-board.
I could also see the ice crystals glittering in the air, making the pillar appear three-dimensional, as if a ray of light extended from the sun right up to my eyes.
The upper part of the sun pillar was visible for about half an hour, while the lower part and the glittering of the ice crystals stayed for about 3 hours until noon.

Author: Peter Krämer, Bochum