Contrails form when the water in engine exhaust mixes with cold moist air and freezes. Normally you see this at 30,000 feet with jet engine exhaust. But in some parts of the world, these conditions can be found at ground level. Here’s a car leaving a contrail in Whitehorse, Canada.
(Photo by Yukon White Light, original here)
Over time these contrails can spread out to form a haze that covers the area.
From a distance this ice fog (Seen here in Fairbanks, Alaska) can look just a like layer of cloud or mist:
Here the individual car contrails quickly merge into a single sheet due to their small size and large number. A jumbo jet obviously creates a much bigger contrail, something more like the building in the middle of the above photo. That’s why you get the more distinct white lines in the sky. And of course, at around 30,000 feet, it’s much more likely to be 40 below than it is at ground level – except for Alaska in the winter.
At the South Pole, they regularly have contrails at ground level:
Here’s an article from 1957 describing how these ground level contrails can persist and spread – just like contrails at high altitude:
[Update 2010-4-26]
See also:
http://orsovolante.blogspot.com/2010/04/ma-come-fanno.html#googtrans/it/en
Which discusses several photos from this photographer:
http://www.airliners.net/search/photo.search?photographersearch=ivandalavia
Like:
Taken in Russia, where there are many places the temperature drops below -40 degrees. Note this is a helicopter, not normally something you’d see leaving a contrail as they don’t go high enough. But when contrail conditions go all the way to the ground, then pretty much anything can leave a contrail
Here’s an account from the South Pole:
http://books.google.com/books?id=ldFt-OquDAUC&lpg=PA45&dq=contrails&pg=PA45#v=onepage&q&f=false
This video’s pretty good, Uncinus. Skip to around the 5 minute mark to see it take off and leave a persistent trail -> http://www.youtube.com/watch?gl=DE&hl=de&v=UtISR1_OzSQ&feature=related
MyMatesBrainwashed
Yes that, video is very good. You can also see an amazing cloud which is formed from persisting contrails while airplane is standing with running engines.
Persistant contrails on ground in south pole is an interesting sight and I read that it also creates a lot of problems because of greatly reducing visibility in the airfield.
Here C-130 leaves contrails on takeoff from south pole:
http://www.youtube.com/watch?v=Z1-jKYfCBPw
And here another video, the same airplane doesn’t leave contrails on take off from south pole, on a different day with probably different weather conditions:
http://www.youtube.com/watch?v=rfca0uUpYQs
Some more amazing LC-130 contrail pictures:
http://www.bohnetphotography.com/AntarcticaImages29.html
http://polar3.home.att.net/october-04.html
Even DC-3 creates contrails in south pole:
http://polar2.home.att.net/oct-08-pics/C-47-DC3-basler-over-station-s.jpg
Excellent photos and video, thank you!
These are like a nice cozy warm blanket for us. They prevent heat loss during the warm nights, even when evaporated to VFR (clear) conditions (water vapor is a potent greenhouse gas). Bye bye clear skies. Hello displaced polar bears and cheap waterfront property.
It’s not actually entirely clear what they do – heat or cool. Have a look at this:
http://www.pbs.org/wgbh/nova/sun/contrail.html
I’d just like to point out that my photo, at the top, was not taken in Alaska, but in Whitehorse, the capital of the Yukon Territory of Canada. We do share a border, but they’re not the same.
Thanks YWL, I’ve corrected the post.
So you admit you have no fucking clue how aircraft “persistant contrails” affect the environment? weather?
What a jackass. You dont actually have to be a rocket scientist to figure this out.
It’s fairly clear that in the day they block sunlight, thus cooling the earth, and at night they block heat radiation from the ground, thus warming it.
What is NOT entirely clear is what the net heating or cooling effect is. Is the heating greater than the warming? Are there secondary effects? See:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-6-2.html
i.e., they think it’s a net warming effect. Wikipedia agrees:
http://en.wikipedia.org/wiki/Contrail#Vapour_trails_or_contrails_and_climate
If you’re done making personal attacks, maybe you’d like to discuss the actual topic at hand?
What are your thoughts on persisting ground level contrails?
Do these examples help you understand how persistent contrails are formed and can spread out?
As someone who lives in a northern state that sees -20 to -30 fahrenheit temperatures every winter, I see scenes like the pictures above all the time (although I haven’t checked out the airport when it gets that cold…I should do that).
The exhaust from cars, factories and houses all form a sort of glittery icecrystal fog that isn’t easily explained to someone who has no concept of what “cold” really is. And when the sun hits it WOW is it ever bright, Sunrises/Sunsets are so beautiful on mornings like those.
I’d love to see some ground level contrails. If you ever do go to the airport on a -30 day (unlikely, I know), then take your video camera.
@Suntours
I understand completely based on relative humidity and temperature how a layer of ice crystals can be formed
which one might call a cloud.
I also understand completely that there have been, and are plenty of ongoing weather modification/ionospheric/atmospheric experiments…also biological warfare and tests on civilian populations.
Because I personally find very peculiar things as I have begun to more carefully watch the skies, this is the reason
why I happen to believe that some of what you call “persistant contrails” are composed of something, or administered in a manner that is quite deliberate and undisclosed for a reason.
Beyond that I am an environmentalist and naturalist. I take it personally.
That is all.
So they make these things look exactly like persistent contrails, and they only create them when the weather conditions forecast persistent contrails?
So how do you know they are not persistent contrails?
Didnt just today I point out that the “sky writing” from the infamous “smiley face” was indistinguishable (by Unicus and others) from a “pendule” laden “persistant contrail”??
In other words, YOU COULDNT TELL THE DIFFERENCE!!!
YOU STATE that “SKY WRITING” is done by mixing a “FINE OIL” in with the exhaust!!!
And this is done at MUCH lower altitudes where the air is usually too warm and not humid enough
to form contrails!
Gotcha.
So if i show you a clip of “chemtrails” with a “rapidly dissapating contrail” there can by more explanations than just
differing altitude.
This means that if there WERE chemtrails(proven or disproven), they could be dispersed at any height and not be distinguished from a so called “normal” contrail.
So what you are saying is that the “chemtrails” you have been seeing are IDENTICAL to contrails? And that you can’t tell the difference?
What is your video about then? Where you stand around looking at a sky full con contrails? I thought you said they are different?
Skywriting is quite different from contrails. The planes are usually much smaller. The trail dissipates at a very consistent rate. They do not fly from horizon to horizon. The trail does not spread out into a layer of cirrus. The trail is often seen to be below cumulus clouds. It often creates letter or symbols.
Now, if you are asking if it’s possible to create a trail that looks very like a contrail, then yes. But you’ve been saying all along that the trails are very different.
So which is it?
I’m busy right now but will get back to you today. Its as if
you DILIBERATELY misunderstand everything I write.
Finally got around to poking through NASA’a “contrail science” education site.
Not only do they present DIFFERENT info than you do but also use very questionable terminology
which doesnt seem to align with the position you state above…”that there are no ‘chemtrails'”.
Well, that sounds interesting, as I generally agree with NASA. Could you be more specific?
I assume you mean this site?
http://asd-www.larc.nasa.gov/GLOBE/science.html
Did you also have to look at the Air Force’s “Contrail Facts”? It does a very good just of explaining many contrail myths.
http://www.af.mil/shared/media/document/AFD-051013-001.pdf
Ground level contrails in antarctica from a C-130 – 1st 20 seconds, again from about 3:15, again at 3:50 – notice also the truck generating a wee one – puts the volume of air passing through a turbine into perspective!!
also clearly visible is hte contrail coming from the exhaust – although there is undoubtably some blown snow there there isn’t once eth a/c is in the air at 5:00
I guess a link might be useful………..http://www.youtube.com/watch?v=UtISR1_OzSQ
groundlevel contrails in saint george utah. im an eye witness to the prop planes headed by skywest which recently closed down this last new year 01/07/2011.
technically “impossible” conditions for “persistent” contrails to form. so what are they? 😮
A new video, Jakutsk (-45 °C):
http://dl.avsim.su/video/47644.mp4
From here: http://www.avsimrus.com/f/on-the-ground-videos-99/vzlet-tu-204-47644.html?action=viewonline