We get our share of gorgeous sunsets in Atlantic Canada and I’m fortunate to receive many beautiful photos from you.
Monday morning, as I scanned my Facebook messages, I saw what I thought was another lovely sunset photo. It didn’t take long for me to realize that this one was special.
The photo was taken by Cathy Martin, Sunday evening in Miramichi, N.B. The vibrant rings or coronae around the top of the setting sunset is apart from a common red sunset.
A corona is an optical phenomenon produced by the diffraction of sunlight or moonlight by individual small water droplets and sometimes tiny ice crystals. But when it comes to the formation of a corona, it doesn't matter if the small particles are transparent or opaque, what does matter is the size and the shape. I believe, in this case, the sunlight is interacting with pollen.
Each spring our trees release clouds of pollen into the air. Unlike water droplets, pollen grains are not always spherical and result in an elongated corona with bright patches and even bands or rings.
These coronae are more easily seen during sunset or sunrise because the light path through pollen-laden atmosphere is longer. When these clouds of pollen pass in front of the sun, a beautiful pollen corona appears.
On Sunday, there was a fairly strong and dry northwest wind across New Brunswick – perfect conditions for tiny pollen grains to be lifted and carried in the air, producing oval-shaped coronae.
What a way to start the week.
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Cindy Day is the chief meteorologist for SaltWire Network.
