We've returned to Arizona nearly a week ago. Immediately upon arrival we got caught up in work and the Holiday whirlwind and here it is Christmas Day before getting a chance to blog. We had planned to go to Rocky Point, MX to visit Margie, but Melinda's back was bothering her, so decided to rest at home, so have enjoyed a quiet Christmas with just us and the cats!
Our 10 days in the Midwest was dominated by clouds. We kind of saw the sun once or twice, but never saw a blue sky. Once taking off from O'Hare for our return, we finally saw blue after ascending above the cloud deck. Kind of a boring flight with only clouds to see and photograph with a stop in Dallas. After a while I started seeing patterns in them, which I guess humans tend to do. But these patterns were of the straight - line structure kind. While posting about fluid dynamics a couple weeks ago, I know little about the movement and dynamics of clouds. I can sort of understand gravity waves and parallel structures, but these patterns seems to be at right angles to each other, which seems weird. The two images shown here are examples, with lines added to illustrate the patterns I see.
Somewhere over what I suspect was Oklahoma, we hit a few gaps in the clouds, and I kept photographing. Of course, the regular readers here know I'm a fan of 3D imaging, so tried a couple taken by 5 - 10 seconds apart, that show some depth between land features and clouds. I like them - hope you do too. These are for cross-eyed viewing which is easiest for me. Cross your eyes slightly so you are looking at the right side of the image with your left eye and vice-versa. It is easiest on the thumbnails, then click on them for the full-size image for more resolution. I particularly like the one at left with the shadow of the cloud being projected onto the haze layer below.
Again, I don't understand the fluid dynamics of clouds, but saw an interesting structure that showed like something welling up from below, then some sort of periodic structure being projected downstream. At left is shown a stereo-pair taken about 15 seconds apart for larger-than-normal baseline, though still not really long enough to show a lot of detail of what is going on. A few minutes later I took another to show a close-up of the upwell section - weird stuff! I was able to take pictures of it for over 8 minutes - if we were going 500 mph that means it was visible for nearly 70 miles! I'm willing to field suggestions...
A little bit before landing we turned nearly south, and while I never saw the plane's shadow part of the glory like the trip up to Chicago, I was able to see enough of the ring to draw a circle on it and estimate the diameter, thus calculate the droplet size from the calculations from Les Cowley's page on corona and glory calculations. Up near Chicago I was able to measure droplet size of 19 microns diameter. Down here in Texas, the droplet size gotta be just a little bigger - I measured the diameter of the ring at 5.3 degrees, indicating a droplet size of 23.5 microns. Doing the calculations on a pair of images, they agreed to a couple percent... Shown here is an image with the saturation upped to ease seeing the rings better.
Another thing I've noticed recently are color bands looking through the Plexiglas windows at certain parts of the sky. I suspected that they were stress birefringence caused by looking at part of the sky that was polarized. We use these properties when inspecting glass for stress concentrations for the mirror castings at work. I remembered I had a polarizing filter in my camera bag, and WOW, the colors really popped out! It is shown at left here. The pattern didn't really change when rotating the linear polarizer, and the colors were still fainly visible w/out the filter, so I think my original theory stands...
One more image to close with. Melinda is still getting chemo treatments for her small-cell lung cancer, just getting a cycle before we came up to Chicago. Of course, an airplane with recycled air, overcrowded with germs from all over, she needed to wear a mask to protect her immune-depressed system. Shown here in full-disguise, she looks non too happy, but put up with it well. Interestingly, to protect from germs, it needs to be replaced every 20 minutes as it loses effectiveness in that timeframe. Fortunately the cancer center is willing to supply us with enough to use for the round trip, and it appears to have worked as we've not caught so much as a sniffle this trip...
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