Tuesday, July 26, 2016

Sunset at Sea

November 2013 found us on a boat looking for birds. You see, Patty was in a local big year competition* and part of the playing field included New Jersey waters.

Thus I was on a boat. In November. As the sun set. It's cold enough on boats in November when the sun is up.  It is real cold when the sun goes down.

No matter, I like cold. I'm not a big fan of boats though.

But we did get to see this spectacular display of Anti-crepuscular Rays. The rays are cloud shadows, and are parallel, only seeming to converge at the anti-solar point (think of how railroad tracks or highways seem to converge in the distance).

Looking in the opposite direction we see the clouds. One can see how the rays match up. There is a cloud directly in front of the sun, so there is a corresponding ray in the center of the sky. Then there are clear patches on either side of the sun, and then clouds again. So we see bright areas next to the central ray, corresponding to the clear patches. And then again shadow rays.

And as the sun set it lit up the underside of the clouds. At least it lit up those that weren't in the shadow of other clouds (you can still see some shadow or crepuscular rays in the images below).

As the sun gets lower on the horizon the light passes through more of the atmosphere to reach our eyes. The sky is blue because gas and dust in the atmosphere are better at scattering the shorter bluer wavelengths of light. As the light passes through more and more of the atmosphere only the longest wavelengths, those at the red end of the spectrum, make it through. Thus the pink and red glow of a sunset.

It was one of the most spectacular sunsets I've ever seen.


* The DVOC's Bob Billings Big Year completion. She won.

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