Tag: clouds

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On my way back to work after lunch today, I looked out the window and saw this feathery wisp of cloud with a clear rainbow pattern running from red at the the top to violet in the middle, then turning plain white below.

Feathery cirrus cloud banded from red to violet.

As I drove south, the colors moved down the cloud, disappearing entirely by the time I got back. By the time I could safely snap a photo, it was already more or less midway down the cloud.

I believe it’s a fragment of a circumhorizon arc, judging by the description:

Look for a circumhorizon arc near to noon near to the summer solstice when the sun is very high in the sky (higher than 58°). It lies well below the sun — twice as far from it (two hand spans) as the 22º halo.

The arc is a very large halo and is close to, and parallel to the horizon. Usually only fragments are visible where there happen to be cirrus clouds.

We’re still 2 months from the summer solstice, but it was 12:38 PM DST (half an hour before true noon), and the sun was apparently near 70.6° high. (The site is aimed at UK visitors, after all.) It also looked too far away from the sun to be part of the 22º halo, plus of course the colors were more well-defined.

This also points out the should-be-obvious fact that ice crystals can still form in the upper atmosphere even when it’s warm — say, 90°F — on the ground, so there’s no need to limit halo-hunting to winter.

I recommend checking out Atmospheric Optics’ additional pictures of circumhorizon arcs, most of which are more complete than this one. Some of them quite spectacular and must have been really impressive to see live.

Update: I spotted and photographed a much larger and more solid arc in May 2010.

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2 contrails and a shadow lit up against the morning sky.

I had to get up early today, early enough that I could still see a couple of stars (or more likely planets, but I’ve lost track of where most of them are right now). When I got to work, I was treated to the sight of these contrails lit up against the morning sky. The rising sun was still behind the mountains, below the frame.

Look at the cloud directly above the contrail on the right, near the leaves. You’ll see a dark nearly-vertical line, which I initially took for a contrail’s shadow, possibly even the one below it. A minute or so later, though, it looked like it might have actually been another contrail, one not lit up by the sun and therefore darker than the cloud behind it.

Oddly enough, half an hour later the entire area was blanketed in fog.

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Corona/Iridescent Cloud

Spotted this on Thursday, between rain showers. It’s a slightly distorted corona, formed by diffraction of sunlight around cloud droplets, splitting the spectrum and producing rainbow-like colors. According to the Atmospheric Optics site, the distortion indicates that the droplet size varies across different parts of the cloud.

This was shot through a window, and I’m 99% certain that the straight line running down the middle of the darker foreground cloud is a reflection from inside the room.

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Friday, September 28:

Clouds with a golden edge at sunset

Adding to the mish-mash of photo sources on here, this is a still frame from a video clip taken out the window of the car. It wasn’t supposed to be a video clip, but my camera has a sliding switch for selecting photo/video/review, and it has a tendency to shift while in a pocket or bag. *grumble*

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Spotted a sundog last Wednesday (September 26), about an hour(?) before sunset.

Sun and sundog above freeway

At least, I’m pretty sure that’s what it was, given the positioning, the brightness, and the reddish coloring on the end nearest the sun. The sharp edges of the reflecting cloud (a fragment of a contrail?) make it look a bit odd, though, like someone cut out a chunk of sunlight and pasted it into the sky.

Here’s a closer view from about a minute later.

Sundog next to a tower.

I was following my usual photo-while driving method of pointing the camera in roughly the right direction, click the button a bunch of times, and hope a few shots come out. (Hooray for digital cameras, where you can delete a bad photo instead of wasting film!)