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

[Mick West]

Nice example on Twitter today:
Source: https://twitter.com/krp234/status/802231166275321856/photo/1

 

[Trailspotter]

Nice example on Twitter today:
Source: https://twitter.com/krp234/status/802231166275321856/photo/1

Did Kevin Palmer replied to your request? The time and exact place of photo will aid the flight identification.

 

[Mick West]

Did Kevin Palmer replied to your request? The time and exact place of photo will aid the flight identification.

No reply yet.

 

[Trailspotter]

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:


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:


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:

 

[Mick West]

Did Kevin Palmer replied to your request? The time and exact place of photo will aid the flight identification.

He sent me this, I'll ask for the location

Date Time Digitized: Nov 24, 2016, 12:50:59 PM

 

[Mick West]

Response:

here are the coordinates: 45.096093, -108.292408

The actual time was 11:50AM MST, not 12:50 like the exif data says.

Content from External Source

18:50 UTC, gives a likely candidate National 8584
https://www.flightradar24.com/2016-11-24/18:45/12x/NCR584/bb5601b

 

[Trailspotter]

Response:

here are the coordinates: 45.096093, -108.292408

The actual time was 11:50AM MST, not 12:50 like the exif data says.

Content from External Source

18:50 UTC, gives a likely candidate National 8584
https://www.flightradar24.com/2016-11-24/18:45/12x/NCR584/bb5601b

Agree. It matches the Sun lighting too:

 

[Trailspotter]

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:

 

[Mick West]

1959:


Via:
http://www.ebay.com/itm/1959-Studie...S-Airforce-Meteorology-Research-/111953830463

 

[Trailspotter]

A new occurrence of the solitary thin trail, spotted on April 8, 2018 in Volgograd, Russia:

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:


LH760 track (KML attached) matches well the location of the photo:


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

 

[Mick West]

Example from above:
Source: https://twitter.com/johnmdudley/status/1060616807965474816

 

[Mick West]

Via Email from Estonia:

Date Time Digitized: Feb 17, 2019 at 1:25:58 PM





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


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

 

[Trailspotter]

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.

 

[Mick West]

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.

 

[Trailspotter]

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:

It takes about six minutes from plane passing to its contrail developing squiggles of such amplitude.


There was a strong tailwind, as the aircraft was following the jet stream during this part of the flight.


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

 

[effalumper]

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...

 

[Mick West]

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...

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.

 

[Trailspotter]

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...

Which direction was the camera pointing at while taking this photo?