Thursday, December 05, 2013

It's a "Sun Pillar"

Photo by Stan Rolfsrud
This morning's rare sun phenomenon has a name, according to Edith, our sweet friend at Mom's Place in Bloomington. Edith had been visiting with the church ladies in Edina earlier this morning before she came by the house and they had seen it too and somebody said it is not a "Sun Dog" (we knew that), it is called a Sun Pole and it is caused by ice crystals in the air at sunrise and it is very rare and you could see it in Edina this morning.
Well, that's fine, Stan said. You could see it in Shakopee too. So when we got home today we looked up "Sun Pole" on the internet and here is what it said: See Edith.
Wikipedia did, however, have a complete section on Sun Dogs, which it isn't, and this is what it said there:
Now this is a garden-variety Sun Dog which was visible in the
west this afternoon. Kathleen spotted it on her way back from Cub.
The sun is setting off to the right. . . too bright to photograph directly.
Sundogs are commonly made by the refraction of light from plate-shaped hexagonal ice crystals in high and cold cirrus clouds or, during very cold weather, these ice crystals are called diamond dust, and drift in the air at low levels. These crystals act as prisms, bending the light rays passing through them with a minimum deflection of 22°. If the crystals are randomly oriented, a complete ring around the sun is seen — a halo. But often, as the crystals sink through the air, they become vertically aligned, so sunlight is refracted horizontally — in this case, sundogs are seen.
So, whatever these are called, they are not sun dogs, but are probably caused by the same idea of ice crystals and cold in the air. Which it is very much today.
Mercifully, the evening news brought a close to our search for a proper name for this sun phenom. Jarred, the local meteorologist, termed it a "light pillar." Thanks for that.
Wiki sez:
A light pillar is a visual phenomenon created by the reflection of light from ice crystals with near horizontal parallel planar surfaces. The light can come from the Sun (usually at or low to the horizon) in which case the phenomenon is called asun pillar or solar pillar. It can also come from the Moon or from terrestrial sources such as streetlights.[1]