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Nice undulatus background.
These contrail shadows are a challenge to interpret. According to Les Cowley, the contrails are always above the layer on which the shadow appears. Could it be that the contrail without a shadow is below that layer? Or possibly the contrail is completely covering its shadow?
Thank you Hans. That video is fascinating. I got caught in flugsnug’s channel and watched a few more. These are very well done, professional videos. Here is one that shows the effect of turbulence on clouds:
So thank you again for helping me discover that.
And good luck with the last two clouds in Cloudspotter! I hope to catch up with you some day. I have now 92 points, missing four clouds and two optical phenomena.
Thank you Keelin. You have so many beautiful pictures, it’s such a compliment to get this comment from you.
And incidentally, we’re having soupy weather after heavy rain. I would say this is mist. I adjusted the color a bit, the orange sodium lights made the whole sky look orange, so I felt like toning it down a bit. (The shaken camera is for artistic impression :-)
Laurence, thanks for bringing up the subject. As I have some background in the matter I am happy to see the phenoms explained. But I do have a problem with one explanation, that of the valley fog. I saw a similar explanation in one of the “cloud of the day” mails not too long ago and tried to correct it. Here is what the BBC site says:
“It develops when cold dense air sinks and settles in lower parts of a valley,”
Actually, when the air sinks, it warms up (because the pressure increases), So that would not lead to condensation, but rather the opposite. The reason the fog forms is that the air that was already in the valley is shielded from the general air motion and cools in place as it radiates away its heat overnight. Water condenses and you get fog.
I looked up valley fog and found another site explaining the types of fog. Their explanation is closer to mine. It has nice pictures too.
Hopes nobody minds my being picky :-)
Thank you Hans, this is informative and funny. So, what makes it possible or likely to catch special contrail effects? Well, first you have to have contrails so this means certain humidity and temperature of the air where the airplanes fly. That’s not something that you can change. Then you need airplanes. That’s something that you may be able to change but it would require moving, not easy to do, I happen to have that ingredient where I am with three major airports and international routes above. Finally, you have to have a serious camera with a big zoom ready and keep watching the skies. Am I missing anything?
So I think, Hans you are a keen observer with some time on your hands. More power to you and bring us more pictures.
BTW, I also noticed that you are very close to the top of the cloudspotter rankings. You only need seven points to get the maximum. I wonder what clouds or optical phenomena you are missing. I hope I am not being too intrusive.
The creativity on this trail has been incredible. I have been enjoying these pictures and comments very much.
Hans, I have a question for you: how do you get those Crow instability pictures? Obviously, you use a telephoto lens, but I am more interested in the circumstances in which you see this phenomenon. Is this happening a lot where you live?
This is Keelin’s second Rothko (first was early in the thread, Dec 15). And Michael, yours is the start of a Pollock.
