Sinusoidal Thin Contrails Explained [Meandering Solitary Hybrid Contrails; the 'Rook' Instability]

Incidentally, I saw a solitary thin trail yesterday. Not as spectacular as above, more like the one in my post #34 in the previous page. It evolved only a little wave and dissipated in about five minutes after its formation by shrinking from the ends. The Emirates A380, flight UAE17, was descending to Manchester and passed about 14 miles southwest of my location:
Screen Shot 2016-11-26 at 17.43.58.png
IMG_8170.JPG
It stopped producing contrail below 30,000 ft or less, but before that it left a typical two-strand hybrid contrail, with one strand dissipating faster than the other:
IMG_8173.JPG IMG_8175.JPG

In five or so minutes, when another flight, AF1486, approached the same patch of the sky, the remnants of the survived strand looked a bit wavy, but did not last much longer:
IMG_8179.JPG IMG_8184.JPG
 
Last edited:
A new sighting of solitary thin trail in Dublin, Ireland on November 30, 2016 at 14:08 UTC.


A380 Contrail
by Ken Meegan, on Flickr
From FR24 playback, the only A380 at the time near Dublin was British Airways flight 286 from SFO to LHR at 39000 ft.

The trail is reminiscent to this OP photo:
Viewed at some angles, such irregular helical shapes may look very different from a sine curve, like, for example:
 
A new occurrence of the solitary thin trail, spotted on April 8, 2018 in Volgograd, Russia:
wx1080.jpg
https://www.volgograd.kp.ru/online/news/3077034/

I asked the photographer about the time of photo, she said it was 18:20 Moscow time = 15:20 UTC. This makes Lufthansa Airbus A380, Flight LH760 Frankfurt -> Delhi, the most likely culprit:
Screen Shot 2018-04-10 at 18.04.22.png

LH760 track (KML attached) matches well the location of the photo:
Volgograd Lufthansa A380 trail.jpg

The plane was exiting the jet stream at the time and could have encountered clear-air turbulence:
Screen Shot 2018-04-10 at 20.08.37.png https://earth.nullschool.net/#2018/...thographic=42.35,51.85,1883/loc=44.706,48.576
 

Attachments

  • FlightAware_DAIMK_EDDF_VIDP_20180408.kml
    46.1 KB · Views: 664
Last edited:
Via Email from Estonia:

Date Time Digitized: Feb 17, 2019 at 1:25:58 PM
DSC_0209.JPG
Metabunk 2019-02-17 09-42-49.jpg



Date Time Digitized: Feb 17, 2019 at 1:27:03 PM
DSC_0210.JPG

These are interesting as they show the solitary hybrid contrail pulling away from the conventional exhaust contrail. The close up also makes it very obvious that it's a hybrid contrail (a portion of the exhaust contrail entrained and amplified by the wake vortices). It has the classic explosive unraveling of the vortex as seen in this video of mine (which shows a more normal pair of vortices):

Source: https://youtu.be/nfwejwWlmt4
 
Via Email from Estonia:

Date Time Digitized: Feb 17, 2019 at 1:25:58 PM
Is the time local or UTC? What was the location?
If it was local time, there were two A380s crossing the Estonian airspace at around 11:25 UTC that day, both following essentially the same route and passing on the sun's side of the capital Tallinn and the second populous city Tartu.
 
Is the time local or UTC? What was the location?
If it was local time, there were two A380s crossing the Estonian airspace at around 11:25 UTC that day, both following essentially the same route and passing on the sun's side of the capital Tallinn and the second populous city Tartu.

Some more info via email:
17.02.2019, 59.4478° N, 24.7351° E (Tallinn, ESTONIA).
First photo (https://yadi.sk/i/8CvYt7CYLVCTXQ) was taken at 13:25, and the second one (https://yadi.sk/i/m21bDrvVV2h8Bw) at 13:25.

...

Mick,
I would like to add a few details to my previous emails.
I saw this meander line about two minutes before the first shot.
The outlines of the meander were clear and sharp. After two minutes (picture1, 13:25),
the outlines in some parts of the meander became more blurred, as well as after the
next two minutes (picture 2, 13:27). From this it can likely be assumed that the meander in this
part of the firmament was formed over the entire visible length at a high speed, much
greater than the speed of any modern aircraft (?).
Content from External Source
I'm not entirely sure what he means with his second email.
 
Some more info via email:
17.02.2019, 59.4478° N, 24.7351° E (Tallinn, ESTONIA).
First photo (https://yadi.sk/i/8CvYt7CYLVCTXQ) was taken at 13:25, and the second one (https://yadi.sk/i/m21bDrvVV2h8Bw) at 13:25.

...

Mick,
I would like to add a few details to my previous emails.
I saw this meander line about two minutes before the first shot.
The outlines of the meander were clear and sharp. After two minutes (picture1, 13:25),
the outlines in some parts of the meander became more blurred, as well as after the
next two minutes (picture 2, 13:27). From this it can likely be assumed that the meander in this
part of the firmament was formed over the entire visible length at a high speed, much
greater than the speed of any modern aircraft (?).
Content from External Source
I'm not entirely sure what he means with his second email.
As the photos had been taken by a smartphone, the time is almost certainly local (UTC+2). This is confirmed by the sun position in the photo from the identified camera location. All this makes the Emirates EK202 flight by A380 A6-EDY being the most likely culprit:
Screenshot 2019-02-18 at 19.57.02.png
It takes about six minutes from plane passing to its contrail developing squiggles of such amplitude.
Screenshot 2019-02-18 at 20.16.32.png

There was a strong tailwind, as the aircraft was following the jet stream during this part of the flight.
Screenshot 2019-02-18 at 20.20.22.png

And, yes, there were good conditions for contrail formation at the flight altitude:
https://earth.nullschool.net/#2019/...thographic=23.11,58.17,3000/loc=24.683,59.380
 
Last edited:
Spotted in the sky above Haarlem, Netherlands 2021-12-21 at about 15:20... it was a cold (-2 C) frosty but very clear day...

WhatsApp Image 2021-12-21 at 15.21.26.jpeg
Nice shot. These are very recognizable wone you know what you are looking for. You can see the spinning vortices where the trail thicken slightly.

2021-12-22_09-46-44.jpg
 
Hi All,

Happy new year, happy 2024. I am new to this forum, and to be frank I had been completely oblivious to...looks at thread name... sinusoidal thin contrails being an actual thing until three days ago when I witnessed it. After some googling, I was relieved to learn it is not something sinister, and I'm close to certain my fellow travellers (it happened on a bus ride) were equally confused/concerned about it.

So here it is.

1704135879498.png
1704135927102.png

Location: I gaze a lot at the sky. The topic of vapour trail visibility has long intrigued me, but I have never been able to fully understand the furthest distance a human would be able to see a vapour trail, so I may be a bit vague/off here with my description and below depiction. At any rate, what I can certainly tell is that the photo I am attaching to this post (cut out of a video my wife made with an iPhone 11) is from main road 74, riding a long distance bus in Hungary. I know, handful of nothing, so to make it easier: the phenomenon was certainly visible between Győrvár and Vasvár, you should look at the middle section of the AT/HU border. We were heading N/NW, and this window is on the left, so, as evidenced by the Sun, this is something of a W/NW direction, I guess.

1704136553203.png

Other info: clear skies, no major meteorological events, pleasant 10°C, on the ground, that is. Date was 2023/12/30 ~15:00-15:30 CET (UTC+1). I'm not that good with reconciling what I see in reality with what I see on Flightradar, so don't have flight candidates, sorry.

A final remark. While I don't have evidence to back it up, the majority of contrails (during that time window) were really...odd, following a slightly squiggly, sine function-like pattern, but none of them were outrageous, maybe mildly interesting at most. This, however, was the undisputed the cherry on the top. The pictures don't do justice, we were late with the video....
 
I had a look at the satellite view of that area to see if there were any clues. The timestamps on the pink line are the time in UTC that the satellite passed over, so this is about 1 hour before the Austrian sighting and 2-2.5 hours before the Hungarian one.

1704202465495.png


There are quite pronounced wave patterns in the clouds to the north, and there are bands of cirrus and contrail fragments to the south (and over the region of Hungary where the other photo was taken.
Closer view:

1704202723435.png


I can't pick out any of the sinusoidal trails but I wonder if the wave patterns in the clouds are linked with this? Presumably some kind of mountain wave effect.
 
I can't pick out any of the sinusoidal trails but I wonder if the wave patterns in the clouds are linked with this? Presumably some kind of mountain wave effect.
Thin contrails are too narrow to be visible in the weather satellite images. The cloud formations probably were at much lower altitudes than the sinusoidal trail, and their wave patterns were not necessarily due to a mountain effect. I recall seeing similar patterns over flat plains and over sea as well.
 
Last edited:
Back
Top