I edited it to inline the second image, sorry if that conflicted with an edit you made.
Do you happen to have any other photos of the trail, even if they look pretty similar, it might help see how it evolves.
Squiggly Sinusoidal Thin Contrails over Europe
Do you happen to have any other photos of the trail, even if they look pretty similar, it might help see how it evolves.
Excellent images I made a quick animation of the contrail, the first four images don't change much, but the fifth one shows it spreading out in a way very consistent with a single semi-persistent hybrid contrail.
John Murrell
New Member
Hello Mick,
The have a few images of the event I saw they are on the link I posted - the problem is I took them from different angles so they probably don't give much of a time sequence. I only took them as some evidence that there was something unusual as in the images of the 'clear air' version I recorded during the transit. The Fov of the video during the transit was very small - I can probably work it out if required but the Sun is of course on 30 arcmin and the images only show a small fraction of the Sun.
John
The have a few images of the event I saw they are on the link I posted - the problem is I took them from different angles so they probably don't give much of a time sequence. I only took them as some evidence that there was something unusual as in the images of the 'clear air' version I recorded during the transit. The Fov of the video during the transit was very small - I can probably work it out if required but the Sun is of course on 30 arcmin and the images only show a small fraction of the Sun.
John
Trailspotter
Senior Member.
Thank you for the info. I'd like to check a few details that could help to verify your identification of the plane.
Time: was it BST or GMT? The FR24 playback figure suggests 10:17 UTC (i.e., GMT), which is 11:17 BST
Trail: was it to south of you or right above you? KLM751 B777 passed slightly to the North of your coordinates, whereas AFR66 A380 passed to the South of you at about the same time.
I was interested in the Focal length, as it gives the Field (angle) of view of the photo. It would help in the estimation of geometrical parameters of the sinusoidal trail. As I can see from your camera specs, you have selected a focal distance in the middle of the camera zoom range. Is it correct?
No sorry that is the only picture.
It was definitely KLM751 as that was the direction the trail went, West to East. The trail was almost overhead but definitely to the South of my location.
Timing may be off. It may have been closer to 11:00 BST. I took the photo and went back in the house to show my wife who was listening to the Archers (if you are not in the UK that is a Radio 4 soap). She told me off for disturbing her
It is aired from 10:00 to 11:15 BSTThe telephoto would have been set about 100mm.
If I'd known how much interest you guys have shown in this, I would have taken more notice - sorry.
Trailspotter
Senior Member.
Thank you again. This is an interesting and very rare phenomenon that is not fully understood. There are a few dozens of recorded cases compiled in another thread:It was definitely KLM751 as that was the direction the trail went, West to East. The trail was almost overhead but definitely to the South of my location.
Timing may be off. It may have been closer to 11:00 BST. I took the photo and went back in the house to show my wife who was listening to the Archers (if you are not in the UK that is a Radio 4 soap). She told me off for disturbing her
The telephoto would have been set about 100mm.
If I'd known how much interest you guys have shown in this, I would have taken more notice - sorry.
https://www.metabunk.org/threads/si...y-hybrid-contrails-the-rook-instability.4539/
We are looking for new observations and associated data on plane types and weather conditions.
Trailspotter
Senior Member.
@trigger
I'd like to ask a few more questions, if I may.
How do you know the trail's direction was from West to East? Did you see the actual plane making it?
I live in the UK and listen to Radio 4 occasionally. From the broadcasting times, it was a Sunday omnibus of The Archers. KLM751 passed over your place near the end of the broadcast, probably when it was already over. Could it be that the trail you saw was left by an earlier plane?
The FR24 playback from 9:00 UTC (10:00 BST) suggests three good candidates flying West to East right over your coordinates - UAL976 at 9:10, KLM758 at 9:11 and DLH435 at 9:25 UTC:
This would correspond to the horizontal FOV of 20°, so the average "wavelength" of sinusoidal contrail would be about 5°. For the contrail's altitude being about 36000 ft (11000 m), the average "wavelength" would be about 3000 ft (1000 m). Could you let me know whether the photo was cropped or not after it was taken, as the cropping to a smaller FOV would reduce the "wavelength" estimate.
I'd like to ask a few more questions, if I may.
How do you know the trail's direction was from West to East? Did you see the actual plane making it?
Timing may be off. It may have been closer to 11:00 BST. I took the photo and went back in the house to show my wife who was listening to the Archers (if you are not in the UK that is a Radio 4 soap). She told me off for disturbing her
I live in the UK and listen to Radio 4 occasionally. From the broadcasting times, it was a Sunday omnibus of The Archers. KLM751 passed over your place near the end of the broadcast, probably when it was already over. Could it be that the trail you saw was left by an earlier plane?
The FR24 playback from 9:00 UTC (10:00 BST) suggests three good candidates flying West to East right over your coordinates - UAL976 at 9:10, KLM758 at 9:11 and DLH435 at 9:25 UTC:
This would correspond to the horizontal FOV of 20°, so the average "wavelength" of sinusoidal contrail would be about 5°. For the contrail's altitude being about 36000 ft (11000 m), the average "wavelength" would be about 3000 ft (1000 m). Could you let me know whether the photo was cropped or not after it was taken, as the cropping to a smaller FOV would reduce the "wavelength" estimate.
@Trailspotter
No I didn't see the aircraft which made the trail. Looking East I could see the squiggles for miles but nothing to the West. I think I've made a lot of assumptions. I saw the KLM flight on FR24 and thought that must be it. I'd forgotten about the -1 hour to UTC. I don't think I would make a very good Police witness
I've asked a friend who also saw the trail what time he saw it. He is an ex BA pilot so maybe has a better sense of timing!
I can confirm that I didn't crop the photo. It is just as it came off the camera. I do remember having to miss getting the sun in the image so confirms that the trail was to the South.
Please come back with any more questions.
Cheers
Dave
No I didn't see the aircraft which made the trail. Looking East I could see the squiggles for miles but nothing to the West. I think I've made a lot of assumptions. I saw the KLM flight on FR24 and thought that must be it. I'd forgotten about the -1 hour to UTC. I don't think I would make a very good Police witness
I've asked a friend who also saw the trail what time he saw it. He is an ex BA pilot so maybe has a better sense of timing!
I can confirm that I didn't crop the photo. It is just as it came off the camera. I do remember having to miss getting the sun in the image so confirms that the trail was to the South.
Please come back with any more questions.
Cheers
Dave
Trailspotter
Senior Member.
I have searched flickr for more pictures of the sinusoidal contrail, reported by @trigger, but found none so far. However, I found pictures of another solitary thin contrail, taken by fdecomite on the previous day, April 11, 2015. The picture series show two planes, one with two engines and the other with four engines, flying "side by side" in approximately the same direction, crossing their paths eventually. The contrail of one of them eventually evolved a solitary thin trail with squiggles:
The photos probably were taken in or near Dunkirk, France, close to the Belgian border at about 18:40 UTC. The FR24 playback suggested the candidate flights TOM52 (B787) and DAL8964 (B747):
I think that the solitary thin trail came from the latter; in the top photo, there is a pair of hybrid contrails formed behind four-engine B747, one of which may have outlived the other. However, it's worth noting for the record that two-engine B787 was still climbing to 37,000 ft; at the time the planes crossed their paths over Dunkirk, it was at about 30,000 ft. The solitary thin contrail probably was formed over the English Channel before that.
The photos probably were taken in or near Dunkirk, France, close to the Belgian border at about 18:40 UTC. The FR24 playback suggested the candidate flights TOM52 (B787) and DAL8964 (B747):
I think that the solitary thin trail came from the latter; in the top photo, there is a pair of hybrid contrails formed behind four-engine B747, one of which may have outlived the other. However, it's worth noting for the record that two-engine B787 was still climbing to 37,000 ft; at the time the planes crossed their paths over Dunkirk, it was at about 30,000 ft. The solitary thin contrail probably was formed over the English Channel before that.
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John Murrell
New Member
I have found another sequence of 4 images showing a twisted con trail from 2008 - in this case only one of the two trails is twisted.
Copies of the images are at https://plus.google.com/photos/114549598170254438527/albums/6138655261859848513 which should have the EXIF data still attached.
Small sample below
The change was quite rapid as can be seen from the exif times. Times should be in UTC.
John
Copies of the images are at https://plus.google.com/photos/114549598170254438527/albums/6138655261859848513 which should have the EXIF data still attached.
Small sample below
The change was quite rapid as can be seen from the exif times. Times should be in UTC.
John
Trailspotter
Senior Member.
Could you change permission to view this album, it is not accessible to public. The sample image seems to be a typical illustration of the Crow instability in a pair of trailing vortices with entrained contrails. Commonly, the vortices will cancel each other, but in extremely rare cases, one vortex may outlive the other and produce a solitary thin contrail.
The whole image sequence will tell whether or not this happened in your case.
John Murrell
New Member
Album images now shared !
Trailspotter
Senior Member.
Thanks. Regrettably, this is just a typical example of the Crow instability.
Trailspotter
Senior Member.
Timing may be off. It may have been closer to 11:00 BST. I took the photo and went back in the house to show my wife who was listening to the Archers (if you are not in the UK that is a Radio 4 soap). She told me off for disturbing her
I have found a video of probably the same sinusoidal trail taken in Marlow (?), Buckinghamshire, not far from your place at about 11:05 BST. Actually, three videos taken at slightly different times, the last one showing the contrail's dispersion:
PS If it is indeed the same contrail, then a likely candidate could be this A340:
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Trailspotter
Senior Member.
There is a follow-up thread with more examples of these trails:
https://www.metabunk.org/sinusoidal...-hybrid-contrails-the-rook-instability.t4539/
I also have a question. How confident are you about your plane identification? Could it be, for example, UAE74 flying in approximately the same direction but farther south?
I suspect that trails of this kind are more likely to form behind heavier planes than B737 or A320.
Trailspotter
Senior Member.
More observations of sinusoidal thin contrails on Christmas day, this time from Italy, some 200 miles southwest from the @zunki's one above (#56).
http://www.ilgazzettino.it/nordest/belluno/scie_cielo_bellunese_belluno_natale-1447085.html
There is a discussion of this publication on the newspaper's FB site including three more pictures of similar trails:
https://www.facebook.com/gazzettino.it/posts/10153834178588069
More interestingly, this or, possibly, another sinusoidal contrail was captured on a time lapse video:
http://video.ilgazzettino.it/index....il-mistero-delle-strane-scie-nei-cieli-veneti
The video shot in the mountains of Belluno fortuitously captured the evolution of a sinusoidal thin trail. It begins with a typical two-stranded hybrid contrail, then one strand dissipates, followed by the amplification of squiggles in the remaining strand, like in several previous cases:
https://www.metabunk.org/sinusoidal...-hybrid-contrails-the-rook-instability.t4539/
The identification of the flight in the time lapse video seems possible, but finding the exact viewpoint in Google Earth to determine the heading of the plane and timing from the sun position may be tricky. Alternatively, a few potential candidate flights could be used as guides in searching for the camera location and viewing directions. My favourite, based on the relative headings and timings of three other contrails in the video is QTR40 A380:
http://www.ilgazzettino.it/nordest/belluno/scie_cielo_bellunese_belluno_natale-1447085.html
There is a discussion of this publication on the newspaper's FB site including three more pictures of similar trails:
https://www.facebook.com/gazzettino.it/posts/10153834178588069
More interestingly, this or, possibly, another sinusoidal contrail was captured on a time lapse video:
http://video.ilgazzettino.it/index....il-mistero-delle-strane-scie-nei-cieli-veneti
The video shot in the mountains of Belluno fortuitously captured the evolution of a sinusoidal thin trail. It begins with a typical two-stranded hybrid contrail, then one strand dissipates, followed by the amplification of squiggles in the remaining strand, like in several previous cases:
https://www.metabunk.org/sinusoidal...-hybrid-contrails-the-rook-instability.t4539/
The identification of the flight in the time lapse video seems possible, but finding the exact viewpoint in Google Earth to determine the heading of the plane and timing from the sun position may be tricky. Alternatively, a few potential candidate flights could be used as guides in searching for the camera location and viewing directions. My favourite, based on the relative headings and timings of three other contrails in the video is QTR40 A380:
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In the past few minutes I watched an A380, Air France flight 6 (Paris to JFK), passing to the south of London at 38,000 feet, and the contrails separated out into two very squiggly lines that later starting to resemble these ones (ie one disappeared before the other). Contrails aren't persisting for very long at the moment so it dispersed before they could progress any further, but it does seem that there is something about the A380 that creates these patterns.
I couldn't get any worthwhile photos, as my office window is filthy and the trails were quite distant.
I couldn't get any worthwhile photos, as my office window is filthy and the trails were quite distant.
Trailspotter
Senior Member.
It is not about A380 as such, as the first records of sinusoidal thin trails predate it. It is about wake vortices that are stronger behind heavier planes. They last longer and therefore are more likely to be decoupled in the presence of aligned atmospheric vorticity (see post #30 in the previous page). If this theory is correct, we can expect more observations of this phenomenon since the introduction of A380.
It looked like this 747 trail was trying to develop into a "squiggly" one this morning but it didn't persist long enough. Hard to see on a phone photo (contrast enhanced)
Trailspotter
Senior Member.
I do not think so. This is how an ordinary two-strand hybrid trail usually looks at this range of viewing angles. I always keep eye on the hybrid trails, hoping to see a "squiggly" solitary trail, but alas…
You could be right. It was quite distant (28 miles when I took that photo) so I couldn't really see it in detail. But I haven't noticed one go into quite such an obvious sine wave shape before.I do not think so. This is how an ordinary two-strand hybrid trail usually looks at this range of viewing angles. I always keep eye on the hybrid trails, hoping to see a "squiggly" solitary trail, but alas…
More squiggly trails over Germany a few days ago: http://www.nordbayern.de/region/nue...ensstreifen-am-himmel-uber-nurnberg-1.5148303
Screenshot with Google translation:
Screenshot with Google translation:
Trailspotter
Senior Member.
Yes, @TEEJ has already posted the link in the sister thread:
https://www.metabunk.org/sinusoidal...rails-the-rook-instability.t4539/#post-181096
The plane that produced this trail has been identified by one of the eyewitnesses as a Qantas A380.
Claus Kern
New Member
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Trailspotter
Senior Member.
The time of the photo from Exif (Date Time Digitized: 21 Apr 2016 13:42:37 CEST) corroborates the identification of the flight as Qantas A380 QFA9. See the post from the sister thread:
https://www.metabunk.org/sinusoidal...rails-the-rook-instability.t4539/#post-181096
Clouds Givemethewillies
Senior Member
Possibly the wrong sort of squiggle, but it was trying. One has more..
Trailspotter
Senior Member.
Probably it was a right one, as the contrail came from a heavy plane (Boeing 747). Actually, it looks similar to the 747 trail I reported in the sister thread:
https://www.metabunk.org/sinusoidal...rails-the-rook-instability.t4539/#post-178568
Have you taken more photos of it?
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Clouds Givemethewillies
Senior Member
Quite a few, showing the four trails evolving into one. . However.. it evaporated without making a big squiggle. Good evidence for something that did not really happen, but might have! I went back up the trail towards the plane, and then back down to the end, in sequence (by file name).
Attachments
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T
toon van elst
Guest
Observed this trail above Ghent, Belgium, 27th of March 2017, 8:15 AM
Which direction were you facing here? It would help with identifying the flight.
I suspect it might have been this one: most of these "squiggly" trails seem to be from heavy planes such as the A380.
(time at the top right is UK time, Belgian time would be 8:14)
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