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*    Colours on the water surface

From: Jari Piikki < jari.piikki@PP.KOLUMBUS.FI>


This is the first time when I write to meteoptic. I am an amateur astronomer and the leader of the Atmospheric light phenomena section of Astronomical Association URSA in Finland. You surely know that Finnish observers found the pollen coronas some years ago. Now again an interesting light phenomena has been found in Finland. I think that it is not known in the literature of the atmospheric light phenomena. This phenomenon is caused by some algaes on the water surface. Very bright coronas, stripes of colours and light arcs have been observed. The colours of the phenomenon are the brightest that I have seen in nature.

Last year colourful arcs and coronas were observed on the water surface by Jouko Markkanen and Krista Vajanto at Kirkkonummi. They could be seen also this year. Around the subsun point there was a colourful corona with brightenings (like pine pollen corona) and five horizontal bows, that had also brightenings at both sides. Around the shadow of the observers there was also rings and a horizontal bow with vertical arcs. This year also new different observations were made by Eero Savolainen at Hirvensalmi and by Jari Piikki, Simo Kaksonen and Teuvo Savolainen at Juva. Eero Savolainen observed a coronalike phenomenon around the reflection of the Sun. At Juva there was a same phenomenon with brightenings and also several stripes of colours before the sunrise. Samples of the water were taken in all of these cases. Many algaes were found but it is unsure, which of them caused the colours. Only one case (Juva) is quite surely caused by Botryococcus-algae.

Click images for better resolution!

[image] [image] [image]

Image 1 and 2: by Jouko Markkanen (Jouko.Markkanen@helsinki.fi), 10th Aug 1996 in Kirkkonummi, Finland.
Image 3: by Eero Savolainen (Eero.Savolainen@pp.inet.fi), 26th Jul 1997 in Hirvensalmi, Finland.

Do you have any observations about this kind of effects? Is anybody interested in simulating the effects? The photos are INCREDIBLE!!!!

Jari Piikki
Ahotie 2 D 3
51900 JUVA

Latest update: 30 Dec 1999

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