Even the sun can have a pet: sundown.
And last week, as high clouds pulled in from above, a prime example of this feature was captured by Skunk Bay Weather videographer Greg Johnson.
During a sundown event, regions of light are seen on both sides of the sun (see example below). These are “the dogs.” Sundogs are also known as “false suns”
The ancients believed that su su was a bad omen, foretelling events such as the death of kings. We now know that sunset usually occurs when the sky is filled with a thin veil of clouds of ice crystals, generally cirrus.
Now, let me show you a video shot by Greg Johnson from his location in northern Kitsap County around 6:30 a.m. last Wednesday. From his camera, you only see one of the dogs.
The sky at sunrise is filled with clouds of tall ice crystals, known as Cirrostratus. You can see the sweeping veil of such clouds from this visible satellite image taken around this time (see below):
Why Sun Dog?
They occur when the ice crystals in the clouds – shaped like hexagonal arrays – are oriented almost horizontally. With that orientation, they preferentially bend light 22 degrees, creating two regions of light (22 degrees on both sides of the sun), as shown in the figure below.
The ice crystals are smaller and fall haphazardly creating a circular halo.
As shown in the image above, many sunsets also have rainbow colors, some of which are also illustrated in the image below.
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These colors are produced by dispersion, the splitting of visible light into its component wavelengths, as it passes through ice crystals, unlike what happens in prisms (see below). ).
Cirrostratus and associated halos and suns are often signs of an approaching weather system, such as a front or a tornado. So while it may not herald the death of kings, it may suggest that the fine weather will come to an end.
And then there are the “other” sunsets…
