Upper Sun Pillar

Last updated on September 16, 2023

The Fascinating Phenomenon of Upper Sun Pillar

Have you ever looked up at the sky and noticed a radiant column of light extending vertically above the sun? This captivating sight is known as an upper sun pillar, and it is a fascinating atmospheric optics phenomenon that occurs under specific conditions. In this article, we will delve into the details of upper sun pillars, exploring their formation, characteristics, and the factors that contribute to their appearance.

What is an Upper Sun Pillar?

An upper sun pillar is an optical phenomenon that creates a vertical beam of light extending above the sun. It appears as a column of light that can range in color from white to vibrant hues, such as pink, orange, or red. This captivating display occurs when sunlight interacts with ice crystals in the atmosphere, creating a stunning visual effect.

Formation of Upper Sun Pillars

Upper sun pillars are formed through a process known as light scattering. When sunlight passes through thin, flat ice crystals suspended in the air, the light waves are scattered in a particular direction. The scattered light waves then interact with our eyes, creating the illusion of a vertical beam of light extending above the sun.

Characteristics of Upper Sun Pillars

Upper sun pillars have several distinct characteristics that make them a mesmerizing sight to behold. Here are some key features of these optical phenomena:

• Vertical Alignment: Upper sun pillars appear as vertical columns of light extending directly above the sun. The length of the pillar can vary depending on atmospheric conditions and the size of the ice crystals present.

• Vibrant Colors: The color of an upper sun pillar can range from white to vivid shades like pink, orange, or red. The specific color observed depends on the angle at which the sunlight is scattered by the ice crystals.

• Pillar Intensity: The brightness and intensity of an upper sun pillar can vary, with some appearing faint and others shining brightly. This variation is influenced by the concentration of ice crystals and the angle at which sunlight interacts with them.

Factors Influencing Upper Sun Pillar Appearance

Several factors contribute to the appearance of upper sun pillars. Understanding these factors can help explain why this optical phenomenon is not observed on a daily basis. Here are some key elements that influence the presence and visibility of upper sun pillars:

• Ice Crystal Shape and Orientation: The shape and orientation of ice crystals play a crucial role in the formation of upper sun pillars. Hexagonal plate-shaped crystals are particularly effective at producing these pillars, as they scatter sunlight in a manner that creates a vertical beam.

• Atmospheric Conditions: Upper sun pillars are more likely to form in cold and calm weather conditions when ice crystals remain suspended in the air for an extended period. These conditions allow for the optimal interaction between sunlight and the ice crystals.

• Sun's Position: The position of the sun in the sky also affects the visibility of upper sun pillars. These pillars are most visible when the sun is low on the horizon, as the sunlight has to pass through a greater distance of the atmosphere, increasing the chances of interaction with ice crystals.

• Light Pollution: Light pollution from artificial sources can hinder the visibility of upper sun pillars. The presence of excessive artificial light can make it challenging to observe the subtle glow of these optical phenomena against the backdrop of the sky.

Other Atmospheric Optics Phenomena

Upper sun pillars are just one example of the many awe-inspiring atmospheric optics phenomena that occur in our skies. Here are a few other noteworthy optical displays that you might encounter:

• Sun Dogs: Sun dogs are bright spots that appear on either side of the sun, often accompanied by a halo. They are caused by the refraction of sunlight through ice crystals in the atmosphere.

• Halo Rings: Halo rings encircle the sun or moon, creating a circular or elliptical shape. These rings form when sunlight or moonlight is refracted through ice crystals.

• Sundogs and Halo Rings at Sunset: When the sun is low on the horizon, sundogs and halo rings can create a stunning display of colors, with vibrant arcs of light stretching across the sky.

• Rainbows: Rainbows are perhaps the most well-known atmospheric optics phenomenon. They occur when sunlight is refracted, reflected, and dispersed by water droplets in the air, creating a colorful arc in the sky.

Capturing the Beauty of Upper Sun Pillars

If you're fortunate enough to witness an upper sun pillar, capturing its beauty can be a rewarding experience. Here are a few tips to help you photograph this mesmerizing phenomenon:

• Use a Polarizing Filter: A polarizing filter can help reduce glare and enhance the visibility of the upper sun pillar in your photographs.

• Adjust Exposure Settings: Experiment with exposure settings to capture the pillar's intensity accurately. Bracketing your shots can also help ensure you capture the full range of colors and brightness.

• Include Interesting Elements: Incorporate interesting foreground or background elements to add depth and context to your photographs. Power pylons, trees, or buildings can create captivating compositions when juxtaposed with the upper sun pillar.

• Be Patient and Prepared: Upper sun pillars are relatively rare occurrences, so patience is key. Keep an eye on weather conditions and be ready to seize the moment when the perfect opportunity presents itself.

In conclusion, upper sun pillars are captivating atmospheric optics phenomena that create vertical beams of light extending above the sun. Formed through light scattering by ice crystals, these pillars exhibit distinct characteristics and are influenced by various factors such as ice crystal shape, atmospheric conditions, and the position of the sun. Understanding these elements enhances our appreciation for the beauty and rarity of upper sun pillars. So, keep your eyes to the sky and be prepared to witness the magic of this mesmerizing phenomenon.

Upper Sun Pillar and Power Pylons. Taken by Cathy Schultz at Cicero, NY on a frosty February morning 2002. ©2002 Cathy Schultz, shown with permission.

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Reference Atmospheric Optics

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