XXXX - OPOD

Last updated on September 16, 2023

Geyser Bows: A Spectacular Display of Atmospheric Optics

Have you ever witnessed a mesmerizing display of rainbows and their supernumeraries? Imagine standing near the Lone Star cone geyser in Yellowstone National Park, USA, surrounded by a faint smell of hydrogen sulphide and other sulphurous gases. Every three hours, this geyser erupts to an impressive height of 50 feet, creating a breathtaking spectacle. But what makes this natural phenomenon even more enchanting is the spray carried by the wind, which forms stunning geyser bows.

The Lone Star cone geyser's spray consists of water droplets that catch the sunlight and refract it, resulting in the formation of rainbows. As you stand near the geyser, you might feel a slight sting on your skin from the larger drops of water in the spray. However, the beauty of these geyser bows makes it worth enduring this minor discomfort. The rainbows exhibit vibrant colors with just a hint of a secondary rainbow. But what truly sets them apart are the multiple supernumeraries, which are additional faint rainbows that appear on the inner edge of the primary rainbow.

One fascinating aspect of these geyser bows is that they undergo changes as the eruption progresses. The narrow drop size distribution within the spray leads to the formation of distinct supernumeraries. These supernumeraries testify to the consistent size of the water droplets. However, as the eruption continues, the mean drop size decreases gradually. This change in drop size has a significant impact on the appearance of the rainbows. They become broader, and their colors become more pastel as the drop size decreases. In extreme cases, when the drop size becomes extremely small, the rainbows transform into fogbows.

To illustrate the evolution of these geyser bows during an eruption, let's compare two stages captured in photographs. The top view, taken four minutes after the lower view, showcases noticeable differences. The top bow appears broader, and the supernumeraries are slightly more widely spaced compared to the lower bow. These variations provide visual evidence of the changing drop size distribution and its influence on the appearance of the geyser bows.

In conclusion, geyser bows created by the Lone Star cone geyser in Yellowstone National Park offer a captivating display of atmospheric optics. The spray carried by the wind, consisting of water droplets, refracts sunlight to form beautiful rainbows. The presence of supernumeraries adds an extra touch of magic to this natural phenomenon. As the eruption progresses, the drop size decreases, resulting in broader rainbows with more pastel colors. So, if you ever find yourself near the Lone Star cone geyser during an eruption, take a moment to witness this extraordinary display of geyser bows and marvel at the wonders of atmospheric optics.

Geyser Bows

Images by Brigitta Sipocz.

©Brigitta Sipocz

‘Rainbows’ and their supernumeraries generated by spray from the Lone Star cone geyser in Yellowstone National Park, USA

Amongst a whiff of hydrogen sulphide and other sulphurous gases, Lone Star erupts to 50ft every three hours.

Wind carried spray has a slight sting on the skin. Larger drops make a gorgeous rainbow with just a hint of a secondary too. Multiple supernumeraries testify to a narrow drop size distribution that changes as the eruption proceeds.

The bow at two stages of the eruption. The top view (shown in the top image on page) is four minutes later than the lower one (full image at left).

The top bow is noticeably broader and the supernumeraries slightly more widely spaced.

The geyser mean drop size is decreasing with time. Rainbows broaden and their colours become more pastel as drop size decreases. In extremis they become fogbows.

Note: this article has been automatically converted from the old site and may not appear as intended. You can find the original article here.

Reference Atmospheric Optics

If you use any of the definitions, information, or data presented on Atmospheric Optics, please copy the link or reference below to properly credit us as the reference source. Thank you!