1. Mick West

    Mick West Administrator Staff Member

    Update: See likely explanation here:
    https://www.metabunk.org/threads/si...y-hybrid-contrails-the-rook-instability.4539/

    [​IMG]
    Photo: Christophe EECKHAUT, (c) CAELESTIA/Belgisch UFO-meldpunt



    [​IMG]
    Photo: André DILDICK, (c) CAELESTIA/Belgisch UFO-meldpunt


    [​IMG]

    Via email:


     

    Attached Files:

    Last edited: Mar 17, 2015
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  2. Mick West

    Mick West Administrator Staff Member

    These are very interesting trails, they have the appearance of the hybrid part of a contrail (the portion of an exhaust contrail made more dense and persistent by the wake vortex), which you often see in loops and curls, but in pairs, and broken up. Like:
    http://contrailscience.com/hybrid-contrails-a-new-classification/
    [​IMG]

    Yet the squiggly trails are continuous single trails.

    They are not just over the Low Country (Netherlands/Belgium), here's a reported example over Poland showing identical structure.
    http://projectavalon.net/forum4/showthread.php?45677-interesting-contrail&p=496936#post496936
    [​IMG]
    [​IMG]

    These photos appear to show a similar phenomenon over Kansas City, USA. With the trail starting squiggly, and getting progressively more so:
    http://geekswithblogs.net/jjulian/archive/2007/12/17/117790.aspx
    [​IMG][​IMG]
     
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  3. captfitch

    captfitch Active Member

    There's something fishy about that first photo. I would say that there was a very brightly lit, reflective, jet that they took a long exposure of and moved the camera. The motion looks repetative, there are little flare-ups in the line and it's almost perfectly uniform throughout. It's just too perfect. So they long exposed the jet and then held the camera still to get the background.
     
  4. Mick West

    Mick West Administrator Staff Member

    One theory I have is that this is a contrail that has become entrained in a horizontal rolling mass of air. Essentially a normal contrail that has been "rolled up" and only the dense core survives, and get progressively more sinusoidal.

    I don't feel this adequately explains the first photo though, as the curves are so dramatic, and the contrail very solid looking. However, consider the two photos taken seven minutes apart.

    [​IMG]

    Clearly the amplitude of the squiggle has increased greatly in seven minutes. The trail itself also seems to have thickened and spread. This suggest that like the Kansas example it did not start out so dramatically squiggly. Could it have started as a straight line, and then a rotor, or series of rotors in the air have formed it into this type of trail?

    [Update] I had the order of the photos the wrong way around. The more compressed photo seems to be more from perspective foreshortening. Wim sent me this photo with a better correction for perspective:
    [​IMG]

    Consider this cloud:
    [​IMG]

    It's a cloud that is twisted inside a rotor of air. Now imagine the cloud is not there, and a plane comes along and leaves a contrail. Could it create the squiggly thin trails we see in the photo?
     
    Last edited: Apr 12, 2014
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  5. Mick West

    Mick West Administrator Staff Member

    i don't think so, as it's very similar to other examples, with the little flare-ups (which you see in the hybrid contrails, exactly the same). Compare with the second photo from Poland. This is just an exceptionally nicely lit example.
     
  6. Mick West

    Mick West Administrator Staff Member

    Here's a video of an example over London's Heathrow airport:

    I've enhanced the contrast:
    [​IMG]
     
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  7. deirdre

    deirdre Moderator Staff Member

    that would explain the inconsistency. I was thinking propeller but the inconsistency didn't make sense.
     
  8. Mick West

    Mick West Administrator Staff Member

  9. solrey

    solrey Senior Member

    Could they be contrails spiraling in horizontal atmospheric vortices?

    http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1965)022<0176:LEITAB>2.0.CO;2

     
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  10. Mick West

    Mick West Administrator Staff Member

    That's essentially what I meant when I said "a contrail that has become entrained in a horizontal rolling mass of air" above.

    "Corkscrew" contrails happen, here's one that's obviously shaped by the rotors that form the row clouds:

    [​IMG]
    [​IMG]
     
  11. Balance

    Balance Senior Member

    What do I know but something doesn't fit right with me, the proportions vs how much they've been distorted from their laid-in-a-straight-line original, plus the varied reflectivity and the "positions" of those high points. Looks more like a "special" effect or as mentioned above - a vibrating camera.


    Though I've heard some pilots do like a drink or two...
     
  12. Mick West

    Mick West Administrator Staff Member

    There's far too many different examples of the same thing. I see no reason to suspect any of the photos.
     
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  13. deirdre

    deirdre Moderator Staff Member

    I think it just got shorter (in viewable length) like if you wrap a hair round your finger.
     
  14. Balance

    Balance Senior Member

    Yeah, probably, just thinking out loud without thinking too hard lol.

    Yup, could be, just my feeble mind can't imagine why the high-vis points are where they are.
     
  15. Mick West

    Mick West Administrator Staff Member

    Well, note the first two photos are taken from different positions, miles apart. I forgot to add this image, which is Wim's estimate of the position of the trail:
    [​IMG]
     
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  16. Mick West

    Mick West Administrator Staff Member

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  17. WeedWhacker

    WeedWhacker Senior Member

    Windshear, at altitude.

    I know there was a long and scientific explanation....but when people begin to learn about windshear, at altitude, then they will begin to better understand why to keep their seatbelts fastened.

    In this case the windshear affected the contrails, after the airplane passed. But, again....in clear air, these sorts of air currents cannot be detected. Unless encountered physically, in some way. OR if they happen to manifest due to condensation, and then become visible due to the clouds that are formed as a result.
     
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  18. Trigger Hippie

    Trigger Hippie Senior Member

    It sort of looks like a missile/rocket trail. Were there any rocket launches at the time the photos were taken?



    missile1.
    http://earthsky.org/todays-image/russian-missile-contrail
     
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  19. Mick West

    Mick West Administrator Staff Member

    I don't think it really looks at all like a rocket trail. It's far too thin, dense, and clean. By the time a rocket trail has got that squiggly, it's broad and fluffy.

    And nobody fires rockets over London.
     
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  20. WeedWhacker

    WeedWhacker Senior Member

    Every experience can be different. Not arguing, just suggesting.

    OH, this was over Great Britain? I need to read the thread more fully.
     
  21. Mick West

    Mick West Administrator Staff Member

    There were multiple examples, two were over London, others over The Netherlands, Belgium, the US (Kansas City), and Poland.
     
  22. WeedWhacker

    WeedWhacker Senior Member

    I understand. Thanks very much!!
     
  23. Balance

    Balance Senior Member

    I can sleep easier now I've seen this :p It illustrates reflective highs and why they're seemingly at random points

    [​IMG]
     
  24. Mick West

    Mick West Administrator Staff Member

    Update From Wim:

     
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  25. Jazzy

    Jazzy Closed Account

    That's the way it seems to me. The lower stratosphere is mostly laminar in behavior. Rolling sheets of air (vortices) may be gently squeezed almost flat, until, at least, they exhibit Crow Instability, and form loops at right angles to themselves. It's all very stable behavior. A rotational moment of inertia is another form of stabilization. How counter-rotating vortices become this is still a mystery.

    Vortices stick to flat surfaces due to the low pressure on their rotational axis: then maybe the vortices consider the topside of the inversion to be a "surface", and "print" themselves as a sinusoid upon that "surface", to Crow's rules. Maybe…

    What a fabulous run of images, Mick. :)
     
    Last edited: Apr 12, 2014
  26. WeedWhacker

    WeedWhacker Senior Member

    Can't help myself, I immediately flashed in my mind, the HBO program "Game of Thrones" (Subtle reference).

    But yes, in terms of the 3-D aspect of the atmosphere and the extremely complex interactions that occur, this is a concept that seems foreign to many peoples' understanding. Since they (those people) are most familiar usually with surface travel, which is a sort of "2-D", in a way.

    Enjoy this short clip!:
     
  27. Sn0w

    Sn0w New Member

    Here are some pictures taken in Sofia, the capital of Bulgaria (Eastern Europe).
    The pictures are shot at 2010 March 18, around 16:30(GMT+02:00).
    The pictures are taken in sequence, they should be covering about about 1 minute interval from 16:27 to 16:28.

    The pictures are not mine, the person who shot them doesn't want to reveal his exact location. I asked him and he gave his permission to "show them to whoever 'experts' you want and play with them as much as you want". (I'll try to ask him for a proper release to public domain, if they are important.)

    So, here are the pictures he published himself. Please note that they might be with degraded quality by the site he used.

    pic_006
    [​IMG]

    pic_007
    [​IMG]

    pic_008
    [​IMG]

    pic_009
    [​IMG]

    pic_010
    [​IMG]

    pic_011
    [​IMG]

    pic_012
    [​IMG]

    I asked the photographer to provide the originals and he gave me this URL onedrive.live.com/file.rar .
    These should contain more metadata and exact timing.

    Now, he claims that he didn't saw any flying object. That the trail have been condensed and didn't move, until it started to fall apart, as is evident from the last photos.


    I'm not very skilled with photo manipulation, but I have managed to cut segments containing the trail, make them into layers, set the background to semi-transparent and overlay them so the trail fits. Even from the last 3 pictures it is evident that the trail parts were moving in different directions and with different speeds. I managed to resize and fit segments from the first panoramic pictures and they followed the same pattern.

    Using my eyes only and making few assumptions, I would say that the time this trail have been straight line is about 3-4 times the time between first and last picture, so 3-5 minutes.

    I hope you might find more useful information in the photo, despite the lack of landmarks. There is only visible part of a poplar tree, 5-10 meters high.
    I also haven't examined the originals yet. I might edit this post if there is relevant information.
     
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  28. Trailspotter

    Trailspotter Senior Member

    I've stumbled upon a couple of recent photographs that may help to explain the origin of these squiggly thin trails.

    Here is a close-up of rather unusual contrail taken in Washington state on August 9, 2014
    [​IMG]
    Source

    and a crop from a wide angle shot of it taken a few seconds earlier:
    [​IMG]
    [​IMG]
    Source

    In the beginning it is a typical double-stranded hybrid contrail, but at the end it breaks down in an asymmetric way with one of the strands waning. Normally, the two strands destroy each other because of Crow instability, so what makes this contrail different? I hypothesise that the two counter rotating wingtip vortices, forming the hybrid contrail strands, interact not only between themselves, but also with an invisible rotor of air, as in #4. The air turbulence would amplify the vortex with the same direction of rotation and curtail the vortex of opposite rotation. I guess that, in the case of a sufficiently strong air turbulence, the second hybrid contrail strand may not form at all.
     
    Last edited by a moderator: Dec 29, 2015
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  29. Mick West

    Mick West Administrator Staff Member

    Interesting. It certainly looks like it is getting there. I'm not sure the scale works.
     
  30. Trailspotter

    Trailspotter Senior Member

    I have been looking for some computational results that can support my hypothesis above and found the following link:

    http://archive.nrc-cnrc.gc.ca/eng/news/iar/2002/01/30/crash-theory.html


    Screen shot 2014-08-25 at 20.12.00.

    If this theory, predicting the aircraft vortices decouple at certain conditions with one of them getting stronger, is correct, then it seems possible that this vortex can produce a single hybrid contrail strand, which, in absence of the Crow instability effect, would persist for longer time.
     
    Last edited: Aug 25, 2014
  31. Trailspotter

    Trailspotter Senior Member

    Actually, all this pictures are from the Netherlands and all but one are of the same contrail. The last image actually is taken in South Rotterdam, but Google (Chrome) has translated non-capitalised 'rotterdam zuid' as 'london' :p
    Another example of the Lorem Ipsum effect: https://www.metabunk.org/threads/lorem-ipsum-of-good-evil-google-china.4248/
     
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  32. Mick West

    Mick West Administrator Staff Member

    Probably unrelated, but this distinct negative squiggle here reminded me of this thread. 20140825-185420-npcz8.

    [​IMG]
     
  33. Mick West

    Mick West Administrator Staff Member

    Squiggly contrail, with obvious regions of rotation (the ripples), but a contrail that has spread out, so not the same.

    http://cloud-maven.com/?p=637
    [​IMG]
    [​IMG]
     
  34. Mick West

    Mick West Administrator Staff Member

  35. Mick West

    Mick West Administrator Staff Member

    An update from Wim via email:



    Liège-050315-2-IMG_4297.JPG
    Liège-050315-1-IMG_4296.JPG
    Photos obtained via Wim van Utrecht of CAELESTIA, who himself received them from Patrick FERRYN of COBEPS (Belgian Committee for the Study of Aerospace Phenomena


    Here's a closeup:
    [​IMG]

    Quite a strikingly bright and clean squiggly line. With the contrast enhanced you can see it's very different to the lower clouds - and to what looks like an aged contrail.
    [​IMG]
     
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  36. Trailspotter

    Trailspotter Senior Member


    In my list, there is one case from 2000, one from 2001 and one from 2002 (Appendix 1):
    https://www.metabunk.org/threads/si...y-hybrid-contrails-the-rook-instability.4539/

    I think the lack of earlier reports is probably due to digital photography being in its infant stage at the time.

    Unfortunately, I do not have Premium FR24 to play back March 5th and to see what plane could have left this trail.
     
  37. trigger

    trigger New Member

    Con Trail.JPG
    klm751.JPG
     
    Last edited by a moderator: Apr 15, 2015
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  38. Trailspotter

    Trailspotter Senior Member

    @trigger
    Where exactly was this photo taken? Also, I would like to see EXIF of this photo, if possible.
     
  39. trigger

    trigger New Member

    Sorry my text seems to have disappeared.

    The photo was taken on Sunday 12th at approx 10:20 BST and facing South. The photo was taken from 51.5782°N, 1.1343°W I stopped the FR24 plot over the location.

    How do I post the EXIF data? The time/date on the picture will be incorrect as I saw the trail, rushed inside to get the camera and then put the batteries in. I didn't set the time/date.

    OK, I found an on-line EXIF viewer.
    Make
    FUJIFILM
    Model
    FinePix S9600
    Aperture
    6.4
    Exposure Time
    1/400 (0.0025 sec)
    Focal Length
    21.6 mm
    Flash
    Off, Did not fire
    File Size
    7.3 kB
    File Type
    JPEG
    MIME Type
    image/jpeg
    Image Width
    448
    Image Height
    336
    Encoding Process
    Baseline DCT, Huffman coding
    Bits Per Sample
    8
    Color Components
    3
    X Resolution
    72
    Y Resolution
    72
    Software
    Digital Camera FinePix S9600 Ver1.00
    YCbCr Sub Sampling
    YCbCr4:2:0 (2 2)
    YCbCr Positioning
    Co-sited
    Exposure Program
    Program AE
    Date and Time (Original)
    2006:01:01 00:00:23
    Max Aperture Value
    2.8
    Metering Mode
    Multi-segment
    Light Source
    Unknown
    Color Space
    sRGB
    Sensing Method
    One-chip color area
    Custom Rendered
    Normal
    Exposure Mode
    Auto
    White Balance
    Auto
    Scene Capture Type
    Standard
    Contrast
    Normal
    Saturation
    Normal
    Sharpness
    Normal
    Subject Distance Range
    Unknown
    Quality
    NORMAL
    Sequence Number
    N/A
    F Number
    6.4
    Exposure Compensation
    N/A
    Focus Mode
    Auto
    ISO
    80
    Color Mode
    Standard
     
    Last edited by a moderator: Dec 29, 2015
  40. John Murrell

    John Murrell New Member

    I have an image of one of these from 2006 which I observed about an hour after the Transit of Mercury - images here http://www.johnmurrell.org.uk/Transit of Mercury Turbulence V2/index.html near the bottom of the page. The other images show a 'clear air' version of something similar crossing the Sun about an hour earlier. You can see the refraction of the sunlight and the distortion caused by the 'turbulance'. There is an animated gif linked to this page or else just step through the individual images.

    John Murrell
     
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