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.

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. :-)

Re: 5/19/2002: Upper air smog

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

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

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....