|Yuba River with Caustics, September 2011|
One of my favorite websites Atmospheric Optics has been on vacation. I still check in every now and then just to see which photos from their archives is up on the front page. I also often use the search option to research some optic phenomenon. I checked in on Monday and found this photo posted there. It's an optic called a Skypool, a phenomenon of the shape of water surface and color. It reminded me of something I had shot a few years ago at the Yuba River. I did a post on it back then. Here's a link to that old post.
|Closeup of Caustics|
Your shifting spectral colours and bright patterns are something else – ‘caustics’ on the river bed. The name caustics is said to come from their appearance of being sharply focused sunlight that would scorch like a burning glass. The lines on the sea or river bed are mostly unsplit into colours – or at least not significantly. The flashes of colour happen when a sharply tilted wave acts like a prism to split the image of the white line into a spectrum.
|Caustics on the Yuba River|