5/19/2002: Upper air smog

Undertoad · 05-19-2002, 04:38 PM

Smog is hated when it's on the ground, but it turns out that smog can also be trapped in a layer, above the earth but below the clouds. In this case the space shuttle Discovery took this shot, in which the great lakes and finger lakes are shining from reflected sunlight. The good news is that the smog condition is probably temporary, as smog needs pretty good conditions to form, as well as sunlight. The bad news that in all its forms it does create health hazards. The ground-level smog is bad, but the smog above is also thought to be bad because it reflects UV rays.

MaggieL · 05-19-2002, 10:42 PM

Anybody who spends much time in a light aircraft around a metro area has *seen* the *permanent" smog layer that caps most cities. It tends to accumulate at the top of the connvective cells that form because of difference of ground temperature, such as cultivated land vs. forrest, or grasslands vs. paved parking lots, or even just rivers vs. dry land.

The air below this layer--typically tops out between 3,000 and 4,000 feet--is quite visibly *dirty*; it's a brownish color, and the airabove it is noticable clearer and bluer.

Even though I'm not working and have zero income, today I broke a one-year hiatus in flying, went up with a flight instructor, and restablished my right to fly and carry passengers.

It feels really good. :-)

russotto · 05-21-2002, 02:33 PM

Quote:

Originally posted by Undertoad

form, as well as sunlight. The bad news that in all its forms it does create health hazards. The ground-level smog is bad, but the smog above is also thought to be bad because it reflects UV rays.

What's bad about that? Just think of it as a substitute ozone layer.

Manitoadlet · 05-21-2002, 03:07 PM

Maybe this is stupid, but how do you know it's smog and not just some other low clouds?

MaggieL · 05-21-2002, 04:15 PM

Quote:

Originally posted by Manitoadlet
Maybe this is stupid, but how do you know it's smog and not just some other low clouds?

Is that question to me?

Because it's there even when the atmosphere is much too dry for clouds. In fact, dry weather intensifies it, becasue rain tends to wash it away. Also it's *brown* rather than simply dark.

If you ever see it you'll know right away.

russotto · 05-22-2002, 09:31 AM

You can see the smog dome over cities even from the ground, in some cases. Yep, definitely brown.

Joe · 05-22-2002, 12:52 PM

The boundary is very distinct right when you pass through it.

After I'm over it a while I don't really want to go back in....

05-19-2002, 04:38 PM	#1
Undertoad Radical Centrist Join Date: Jan 2001 Location: Cottage of Prussia Posts: 31,423	5/19/2002: Upper air smog Smog is hated when it's on the ground, but it turns out that smog can also be trapped in a layer, above the earth but below the clouds. In this case the space shuttle Discovery took this shot, in which the great lakes and finger lakes are shining from reflected sunlight. The good news is that the smog condition is probably temporary, as smog needs pretty good conditions to form, as well as sunlight. The bad news that in all its forms it does create health hazards. The ground-level smog is bad, but the smog above is also thought to be bad because it reflects UV rays.

05-19-2002, 10:42 PM	#2
MaggieL in the Hour of Scampering Join Date: Jan 2001 Location: Jeffersonville PA (15 mi NW of Philadelphia) Posts: 4,060	Anybody who spends much time in a light aircraft around a metro area has seen the permanent" smog layer that caps most cities. It tends to accumulate at the top of the connvective cells that form because of difference of ground temperature, such as cultivated land vs. forrest, or grasslands vs. paved parking lots, or even just rivers vs. dry land. The air below this layer--typically tops out between 3,000 and 4,000 feet--is quite visibly dirty*; it's a brownish color, and the airabove it is noticable clearer and bluer. Even though I'm not working and have zero income, today I broke a one-year hiatus in flying, went up with a flight instructor, and restablished my right to fly and carry passengers. It feels really good. :-) __________________ "Neither can his Mind be thought to be in Tune,whose words do jarre; nor his reason In frame, whose sentence is preposterous..."

05-22-2002, 12:52 PM	#7
Joe Master of the Domain Join Date: Sep 2001 Location: AZ Posts: 221	smog covers the earth The boundary is very distinct right when you pass through it. After I'm over it a while I don't really want to go back in.... __________________ One planet, many worlds.

05-21-2002, 03:07 PM	#4
Manitoadlet Person Who Has Posted Join Date: Apr 2002 Posts: 2	Maybe this is stupid, but how do you know it's smog and not just some other low clouds?

05-22-2002, 09:31 AM	#6
russotto Professor Join Date: Jan 2001 Posts: 1,788	You can see the smog dome over cities even from the ground, in some cases. Yep, definitely brown.

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