Israel Lowitz Arc

Last updated on September 16, 2023

The Israel Lowitz Arc: A Rare Atmospheric Phenomenon

Have you ever heard of the Israel Lowitz Arc? It is a fascinating atmospheric optical phenomenon that was first recorded by Professor Tobias Lowitz in St Petersburg back in June 1790. This elusive arc is often difficult to identify and characterize due to variable cloud cover and the limited rotation of plate crystals about the Lowitz axis. However, on March 7, 2007, during a spectacular halo display over Israel, the arc made a rare appearance and was captured in images taken by Pennina Neumann.

Discovering the Israel Lowitz Arc

While searching through Pennina's images for the expected Parry arc beneath the 22° halo, a trace of another arc caught the attention of researchers. After enhancing the image using unsharp masking and embossing techniques, it was confirmed that this was indeed the elusive Lowitz arc. Further analysis revealed that the arc was present in three more images, and a comparison with the HaloSim simulation confirmed its identity.

The Influence of Sun Elevation on the Lowitz Arc

It is interesting to note that the sun's elevation during the Israel Lowitz Arc display was similar to that observed by Professor Lowitz over two centuries ago. Both instances only showed the lower arc, as the high sun rendered the corresponding upper arc weaker. This phenomenon could be attributed to plate crystals having limited rotation about the Lowitz axis. However, more research is needed to fully understand this unique behavior of the Lowitz arc.

Challenges in Identifying and Characterizing the Lowitz Arc

The identification and characterization of the Lowitz arc pose significant challenges due to various factors. Variable cloud cover often obscures the arc, making it difficult to distinguish from other atmospheric optical phenomena. Additionally, the limited rotation of plate crystals contributes to the rarity of observing this arc. To overcome these challenges, researchers suggest taking multiple images with a fixed camera position over an extended period and comparing them to identify and analyze the Lowitz arc accurately.

Appreciating Halo Displays

Despite the challenges involved in studying the Lowitz arc, it is crucial to take the time to appreciate and enjoy halo displays. These displays offer a captivating visual spectacle, showcasing the beauty and complexity of atmospheric optics. Whether it's the elusive Lowitz arc, the familiar 22° halo, or other atmospheric phenomena, halo displays remind us of the wonders of nature and the intricate workings of light in our atmosphere.

In conclusion, the Israel Lowitz Arc is a rare and intriguing atmospheric optical phenomenon that was captured during a halo display over Israel in 2007. Its identification and characterization present challenges due to variable cloud cover and limited rotation of plate crystals. However, with advancements in imaging techniques and continued research, we can hope to unravel more secrets about this elusive arc. So, the next time you witness a halo display, take a moment to appreciate the beauty and mystery of these atmospheric phenomena.

High Sun Halos imaged by Pennina Neumann

(images) during Israel's spectacular display on

March 7, 2007. ©Pennina Neumann.

The previous "Todays Feature" showed the high sun Parry arc and extreme distance from the sun of the sundog during the 'high sun' halo display over Israel. While searching more of Pennina's images for the Parry arc expected beneath the 22° halo, I noticed a trace of another arc on the image at left. Could it be the fabled Lowitz arc? Enhancement by unsharp masking and embossing revealed that it was likely. The arc was then found on three more images. Finally, the comparison with the HaloSim simulation at right confirmed it.

Interestingly, the sun's elevation was almost the same as that in St Petersburg when professor of chemistry Tobias Lowitz first recorded the controversial arc in June, 1790. He also saw only the lower arc. The high sun renders the corresponding upper arc weaker but its failure to show could also be due to plate crystals having only limited rotation about the Lowitz axis. Variable cloud often makes Lowitz arc identification and characterisation difficult. Ideally, many images should be taken with a fixed camera position over a long period followed by comparison of individual images or stacking. But above all, make time to enjoy halo displays!

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