Trickers and Wegeners Arcs in Jordan

Observer: Michael Heiß, Greifswald – Germany
Website of the phenomena: www.meteoros.de

The following observation was made along the motorway leading from Wadi Rum to Akaba in Jordan on December 4, 2016. At a position of 29.641553North and 35.196915 East, halo activity reached its maximum between 9:30 and 9:45 a.m. EET(East European Time). The temperature was at 14°C. After it had been clear, cloudiness now increased (Cirrus clouds).

Some fragments of the 22°-halo and both sundogs had already been visible in scattered cirrus clouds the evening before and through the morning hours. The cirrus clouds increased during the morning, becoming scattered over the whole sky by 9:30 EET. During a stop by the roadside, the whole scale of haloes could be observed. The sun was surrounded by a bright 22°-halo, both sundogs, upper tangent arc and a complete and colourful Parry arc. A faint circumzenithal arc was also visible. While the cirrus clouds spread more and more over the sky, some fragments of the parhelic circle became visible, merging to form a complete parhelic circle which was so bright that it got a brownish-red upper rim. The two characteristic bulges in the areas of the 120°degree-sundogs were also clearly visible. The highlight of the phenomenon, however, was Tricker´s anthelic arc which appeared for about 5 minutes as an accentuated “V” turned upside down opposite the sun beneath the parhelic circle. At the point where the “V” tapered, the anthelion could also be detected.

The cirrus clouds rapidly thickened, which caused most haloes to fade away. Only the 22°-halo persisted for several hours before disappearing in the afternoon.
Wegeners antihelic arc appears if the USM method is used.

All pictures are taken with a full-frame camera (Canon 6D) at a focal length of 24 millimetres.

A re-visited 13° halo observation from 2013, and some thoughts about the responsible crystal faces

Circular halos of 12°-13° in radius are named “exotic” because they do not fit in the (nowadays) traditional sequence of well-documented halo radii from pyramidal ice crystals (9°, 18°, 20°, 22°, 23°, 24°, 35°, 46°). The first known photographs of such a halo were obtained at the South Pole, December 11th-12th, 1998, by Walter Tape, Jarmo Moilanen and Robert Greenler. Up to now, there are only few more (Michael Theusner, Bremerhaven, October 28th, 2012; Nicolas Lefaudeux, Paris, May 04th, 2014).

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Rare Subhorizontal Halos

I was flying from London back home to Berlin on September the 11th 2016 . The flight was operated by British Airways. The airplane was located above Hankensbüttel / Wittingen (DE, Niedersachsen) when I observed a bright subsun and some bringt subparhelia. The suns altitude was about 40° at this time. For this fact the halos appeared very steep below the horizon, which made it difficult to observe them.

In addition to the subsun and the left subparhelion, the sub parhelic circle was visible for some moments. It appeared in the shape of a bright tail of the subparhelion. But for some moments I could see the sub parhelic circle between them.

The following image was taken with a Samsung smartphone.

2016-09-11_unter-halo

According to the theory, the sub parhelic circle can be produced by horizontal oriented ice crystals. But the sub parhelic circle grows left and right from the subparhelia, so that there is actually a gap between the both subparhelia. During my observation from the airplane, the sub parhelic circle was visible between the both subparhelia. How is it possible?

2016-09-11_simulation2016-09-11_unter-halo_usmThe simulation software called “HaloSim” (L. Cowley & M. Schrieder) leads to a first clue. The sub parhelic circle between the subparhelia could only be simulated with the help of pretty flat Lowitz-oriented crystals. In addition, the simulation shows an “X” which is crossing each of the subparhelia. These are the reflected lowitz arcs or also knows as “Schulthess bows”. The bows are also visible in my picture from September the 11th 2016.

The 1th picture shows a simulation by HaloSim (L. Cowley & M. Schroeder). The 2nd picture was modified with the help of an unsharp mask to highlight some details.

The simulation shows also the 46° tangent arcs (EE52), also knows as 46° lowitz arcs. Especially the lower middle 46° tangent arc (EE52B) is standing out. However, I neither saw these bows nor I found them in my pictures. The reason for that is the fact that my attention was directed to the area near the subsun. Another reason may be the fact, that there were no halo active ice crystals in the higher air layers.

The simulation and the observation do match pretty well and are convincable, so that one can say, Lowitz-oriented crystals are responsible for the presented halo display.

2016-09-11_unter-halo_video-usm

This picture was stacked from a video file. The frames were aligned and modified with photoshop.

I want to thank Michael Großmann and Alexander Haußmann for helping me with the analysis.

Author: Andreas Möller, Berlin, Germany

Elliptical halos with small radii observed from Mt. Fichtelberg

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On April 22nd, 2016, I worked on Mt. Fichtelberg (1215 m above sea level) in the German Ore mountains. I noted several interesting phenomena in the sky. An upper air flow from southerly directions had brought in Saharan dust as indicated by a prominent ring of Bishop around the sun, which had already been visible since the day before. On the 22nd, aerosols produced a rather milky sky, with additional thin and high Altocumulus lenticularis clouds due to foehn from the south. These clouds showed a pronounced iridescence when coming close to the sun. This motivated me to investigate the sky in the proximity of the sun in more detail by using dark sunglasses, as it would have been a pity to miss these gorgeous colors.

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November 1, 2014 – Lowitz phenomenon in Miesbach

miesbach_46lowitz

On November 1, 2014, Thomas Klein observed in Miesbach/Bavaria a halo phenomenon with multiple appearances. In the morning hours, only the standard halos 22°-ring, both parhelions, upper tangent arc and parry arc were visible. Right after lunch, the first phenomenon was observed in the centre of Miesbach. Beside the halos above, also rare halos were documented, an almost full parhelic arc, both 120° parhelions, left Liljequist parhelion, supralateral arc and cirumzenithal arc. Not be seen but documented on pictures were also helic arc and wegeners arc.

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Odd radius display in California

Zinkova-title
At around 2 p.m. on February 23, 2016 I was  filming superior mirage of a distant land and superior mirage of a  sea surface. From San Francisco the superior mirages are observed  on warm days, and February 23 was not an exception. The air temperature was higher than 70 degree Fahrenheit. At some point I took my eyes from the horizon and looked up. The sight amazed me. I was looking at bright, circular halos that I have never seen before. Later I found out that the halos I observed were  9 °, 18 °, 20 °, 24 ° and 35 ° radii, and 24 ° upper tangent arc. and that the display has a name: odd radius halos.

Pictures with a different methods of encroachment

From the pictures posted on the NET by other people I found out that a similar display was seen at Ballico, California, which is 50 miles (80 kilometers)  east  of San Francisco. Another observer was located in Sunnyvale 20 miles (32 kilometers) south of San Francisco. It often happens that odd radius halos are observed over vast distances. As a matter of fact on April 14, 1974  the odd radius halos display in England was overdosed at the locations that were 460 kilometers apart.  From Claudia Hinz I’ve learned that odd halos display in Middle Europe are associated with prominent cold fronts that slowly move from north to south, but no cold front arrived in San Francisco on the next day. February 24, 2016 was only slighter cooler than February 23.

halo map-4k

Author: Mila Zinkova, San Francisco