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    Re: Horizon refraction: photos of changes
    From: Frank Reed
    Date: 2013 Apr 19, 20:16 -0700

    Marcel, you wrote:
    " The cooling towers indicate that this atmosphere is likely far from corresponding to a stratified model one. The purpose of these towers is to transfer heat into the atmosphere and the convective air flow of the cooling towers changes the environment to a local "hot spot"."

    No. I don't think that has any significant impact on the refraction phenomena here. They're not chimneys. The temperature difference is not great, and there's very little convection above them. The tops of those towers, by the way, are 500 feet up, well above the phenomena we've been talking about. Besides those are sixteen miles away! Don't forget the compression of distances that occurs in telephoto images.

    But of course, like every location, this is a unique location with its own special variability of local atmospheric conditions. I'm not suggesting that any general conclusions should be drawn from a single pair of photos; only showing another case where real variability in terrestrial refraction is easily captured if you can find a long enough sight line with clearly identifiable structures along it. I'm attaching a map of Narragansett Bay for context. The white line shows the line of sight in the photos. The yellow dot was the camera location. The first red dot is the pier at the end of Gould island, two miles out. The second red dot is the Mount Hope suspension bridge. The third red dot is the location of the cooling towers. And the final red dot is the approximate location of the spot on the ridge that constitutes the "hill" horizon.

    PS: Of interest this evening, note the towns of North Kingstown, Rhode Island towards the left and Dartmouth, Massachusetts towards the right (just west of historic New Bedford). The former is the home of the (probable) Boston bomber, Tamerlan Tsarnaev's, young wife. The latter is where he was enrolled in college.

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