PDA

View Full Version : Air traffic is affecting the skies



David Hall
2001-Nov-18, 10:16 AM
This is a very interesting article about how air travel is affecting the weather. The ban on air travel on Sept. 11 let researchers see what the constant jet traffic is doing to the environment. Specifically, jet contrails tend to create high cirrus clouds that can trap heat.

http://www.nytimes.com/2001/10/30/science/earth/30CONT.html
(note: NYT requires registration before viewing)

While it doesn't address it specifically, I was thinking about how this could be affecting astronomical viewing. I was shocked to see how many high clouds were created by jet contrails. This must be affecting the clarity of the skies. Perhaps some of the haziness a lot of people have to contend with is caused by air traffic?

interstellaryeller
2008-Nov-11, 09:58 PM
I agree. 110%. I have seen contrails to my west on summer evenings blossom into overcast skies at twilight.

Nowhere Man
2008-Nov-11, 11:09 PM
Beware! Thread necromancy!

Fred

flynjack1
2008-Nov-12, 12:57 AM
If you want to know where to expect the most contrails you will want to refer to High Altitude Enroute navigation charts. The Jet routes are depicted on these charts relative to navigation aids such as VOR's. If you are unlucky enough to be near a major route and a VOR station it may be worse than for folks who live in areas more remote. Of course these contrails are moving with the upper level winds so as they disperse they will still affect viewing but not be as obvious. Aircraft can also be cleared direct where they are not required to stay on a route, this is done to reduce air traffic conjestion and reduce enroute delays. It will remain a problem until they start making antigrav aircraft(just kidding).

Gigabyte
2008-Nov-12, 04:30 AM
Somewhere I've got some excellent links to images about this. It is unbelievable (until you see it) how much damage contrails do to visibility, and they even lower local temperatures, due to reflecting sunlight.

jt-3d
2008-Nov-12, 07:47 AM
Somewhere I've got some excellent links to images about this. It is unbelievable (until you see it) how much damage contrails do to visibility, and they even lower local temperatures, due to reflecting sunlight.


http://antwrp.gsfc.nasa.gov/apod/ap041013.html

Not that I agree that contrails can affect weather since they don't happen everyday, everywhere. Besides, what with all the global warming talk, it seems like lowering temperatures would be a good thing.

Gigabyte
2008-Nov-12, 04:42 PM
I've read papers that show the cooling from contrails is actually counteracting warming, in areas where air traffic is heavy. Like Europe and the US. If you live near a major airport, you can see the cloud cover build up, with the right weather conditions the contrails form an overcast, decreasing the amount of sunlight reaching the ground.

It's kind of creepy at times. And would definitely mess with any ground based observations in the area.

Argos
2008-Nov-12, 04:51 PM
Beware! Thread necromancy!


David Hall... I used to like his posts.

Gigabyte
2008-Nov-12, 04:56 PM
This is a great thread. I remember after 9-11 how clear and beautiful the skies were for a couple of weeks. (I live near airports, and under a major traffic pattern for flights).

Another problem with contrails is shooting a movie based in the past. With digital retouching it isn't as much of a problem now, but just one contrail in a shot can ruin a take. Or end up costing money to remove it.

Once you start paying attention to contrails, you realize just how much they can alter the view of the sky.

http://www-pm.larc.nasa.gov/sass/sfc.contrail.1.26.01.JPG

If you observe carefully, you can even watch contrails turn into what looks like cloud cover, but isn't.

flynjack1
2008-Nov-15, 03:17 PM
You dont have to live near a major city to have an issue with contrails. Major east west traffic routes tend to have choke points where most of the high level traffic passes. Albuquerque is one such area, El Paso is another. At these locations its most notable too because of the dryer airmasses in the west(less percentage of normal cloud cover). Back east where there are more cloudy/hazy days its less apparent. I can personally vouch for the observations post 911, as I was out in the mountains during that time. It was spooky not to hear air traffic too! Normally I would hear and see air traffic even out in the boonies of New Mexico.