Contrail of the Day
I snapped this a few minutes ago, looking west from Santa Monica:
At first glance it looks like two jets flying in parallel, but I think that actually the upper jet is somewhat higher than the lower jet. It’s hard to see, but it also looks like the upper jet has four engines, while the lower seems to have two:
This might explain the longer persistence of the upper jet. It also might account for the curious way the upper jet trail goes from four mingled streams into two separate streams that then twist away and break up. The sequence seems very similar to this one from Clouds of the World, published in 1972 (photos probably taken in the late 1960s):
See here again how it start out as four trails, they merge and separate into two trails, and then break up into two swirly trails due to wake eddies.
In my photo it looks like the outer trails simply fade out sooner than the inner trails. This suggests that the inner engines are on a higher power setting than the outer engines (and hence produce more water vapor).
Friday 21 Dec 2007 | Uncinus | contrails
Very beautiful and interesting !
agnès
I’m going to write a paper about the contrails on my blog. I need your science !
agnès
Actually these are twins, probably 757s and/or 767s and/or 777s going to Hawaii from probably Dallas, Houston and/or Atlanta. From DFW, IAH and ATL, the route is usually right over LAX westbound. http://ryanthepilot.blogspot.com
I see two at a time often. And going in different directions, not so much parallel like that. Nice photo.
This is the photo someone identified as ‘chemtrails’. Now I can see where some of it is ‘contrails’ but isn’t the main part actually a cloud?
I hope this html works.
Well, contrails are clouds, if the conditions are right a contrail will spread out and turn into cirrus clouds.
What you are seeing here (in the upper part of the photo) is a contrail being spread by wind sheer. The contrail is essentially smeared across the sky, leaving a trail of cirrus clouds behind it.
The lower part of the photo is mostly cloud layer. This gives an indication of how much moisture there was in the atmosphere. The clouds would probably have spread anyway - the contrails just sped it up by adding more moisture and aerosols.
Thanks for the information.