Sundog in fall streaks

Last updated on September 16, 2023

Sundog in Fall Streaks: A Delicate and Fibrous Atmospheric Phenomenon

When it comes to atmospheric optics, one of the most captivating and ethereal sights is the occurrence of a sundog in fall streaks. This mesmerizing phenomenon involves the interplay between ice crystals, sunlight, and the vast expanse of the sky. In this article, we will delve into the intricacies of sundogs in fall streaks, exploring their formation, characteristics, and the mesmerizing beauty they bring to our skies.

The Formation of Sundogs in Fall Streaks

Sundogs in fall streaks occur when streams of ice crystals, known as fall streaks, descend from high cirrus clouds. These cirrus clouds are composed of ice crystals formed at high altitudes where temperatures are extremely cold. As these ice crystals plummet towards the Earth's surface, sunlight interacts with them in a remarkable way, giving rise to the breathtaking display of a sundog.

The Role of Sunlight and Ice Crystals

The key to understanding the formation of sundogs in fall streaks lies in the interaction between sunlight and ice crystals. Each individual ice crystal acts as a tiny prism, refracting and dispersing sunlight as it passes through. This refraction causes the sunlight to split into its constituent colors, just like a rainbow. Moreover, the specific shape and orientation of the ice crystals determine the angle at which the light is refracted.

Delicate and Fibrous Sundogs

What makes sundogs in fall streaks truly enchanting is their delicate and fibrous appearance. The fall streaks, illuminated by refracted sunlight, create slender streaks of light that resemble delicate fibers strewn across the sky. This ethereal quality adds a touch of wonder to the already captivating display of a sundog. The interplay between the ice crystals and sunlight creates an intricate tapestry of light that seems to dance across the heavens.

The Visual Characteristics of Sundogs in Fall Streaks

Sundogs in fall streaks exhibit several visual characteristics that make them stand out in the sky. These include:

• Position: Sundogs are often seen as bright spots of light on either side of the Sun, forming a halo-like effect. In the case of fall streaks, the sundogs may appear elongated due to the presence of the fibrous streaks of light.
• Color: Sundogs typically exhibit a range of colors, with red closest to the Sun and blue farthest away. This color gradient is a result of the dispersion of sunlight by the ice crystals.
• Brightness: The brightness of sundogs can vary depending on the density and size of the ice crystals, as well as the angle at which sunlight interacts with them. Under ideal conditions, sundogs can be remarkably bright, casting their ethereal glow upon the surrounding sky.

The Role of Atmospheric Conditions

The occurrence of sundogs in fall streaks is dependent on specific atmospheric conditions. These include:

• Presence of Cirrus Clouds: Sundogs in fall streaks are most likely to occur when cirrus clouds are present at high altitudes. These clouds provide the necessary medium for the formation of ice crystals.
• Temperature and Humidity: Extremely cold temperatures and high humidity levels are conducive to the formation of ice crystals within cirrus clouds. These conditions create an environment where fall streaks can develop and descend towards the Earth's surface.
• Sun Angle: The angle at which sunlight interacts with the ice crystals plays a crucial role in the formation and visibility of sundogs. Sundogs are most visible when the Sun is low on the horizon, such as during sunrise or sunset.

Capturing the Beauty of Sundogs in Fall Streaks

For photographers and sky enthusiasts, capturing the beauty of sundogs in fall streaks can be a rewarding and awe-inspiring experience. Here are a few tips to enhance your chances of capturing this phenomenon:

• Timing: Plan your photography session during the golden hours of sunrise or sunset when the Sun is low on the horizon.
• Location: Look for open spaces with an unobstructed view of the sky to maximize your chances of spotting and photographing sundogs.
• Equipment: Use a DSLR or mirrorless camera with a telephoto lens to capture the intricate details of the sundogs and fall streaks.
• Settings: Experiment with different exposure settings to achieve the desired effect. Bracketing your shots can help capture the full dynamic range of the scene.
• Patience: Sundogs in fall streaks are relatively rare occurrences, so be patient and persistent in your quest to witness and photograph this captivating phenomenon.

In conclusion, sundogs in fall streaks are a truly captivating atmospheric optics phenomenon that combines the delicate beauty of fall streaks with the ethereal glow of sundogs. Understanding the interplay between ice crystals, sunlight, and atmospheric conditions allows us to appreciate the intricacies of this mesmerizing display. Whether you witness sundogs in fall streaks firsthand or capture their beauty through photography, they are sure to leave an indelible impression on anyone fortunate enough to experience them.

Sundog in fall streaks imaged by Lauri Kangas (site) in Southern Ontario January '04. Fall streaks are streams of ice crystals falling from high cirrus. Here sunlight refracted by individual ice crystals lights the streaks to form a wonderfully delicate and fibrous sundog. Image ©Lauri Kangas, shown with permission.

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!