Actually errors in this as known to NASA U2 pilots nearly caused loss of the U2 during ozone hole science flights in 87. The plane had partial wing stall in turn deep over Antartica and took 30,000 feet to recover.
Couple of questions. First looking a figure a (uv index run NP) if I understand it correctly. South and north look same per latitude except for perturbation from ozone hole in south spring months. Look at line 2 for each. Is this correct interpretation?
Second, tropics I guess is lower because of sun angle is more direct having a shorter path length through ozone layer. That does not seem quite correct as due to temperature and effect of earth spin atmosphere is thicker at equator, but perhaps that is secondary effect. Basically at 20km altitude air pressure is close to same at poles and equator. Sorry my ignorance I am EE but worked decades in atmospheric sciences so I likely have some misunderstandings of atmospheric science.
Thanks for your comments. At first sight the uvi does look about the same in both hemispheres, but that’s only because the latitudinal gradients are so steep. If you look closely you’ll see that the contours are displaced towards higher values in the south. The uvi is indeed more intense at the equator because of the more direct path through the absorbing ozone (also because there’s less of it).
The gradients in density are, as you suspected, only secondary effects.
I guess another question what is density profile by latitude and altitude to 30km?
The ozone profile is also displaced to higher altitudes in the tropics. In polar regions the tropopause is much lower too.
(That wouldn’t have affected the aircraft flight, but high ozone levels in the cockpit may have impaired pilot performance).
Actually errors in this as known to NASA U2 pilots nearly caused loss of the U2 during ozone hole science flights in 87. The plane had partial wing stall in turn deep over Antartica and took 30,000 feet to recover.
Richard,
Couple of questions. First looking a figure a (uv index run NP) if I understand it correctly. South and north look same per latitude except for perturbation from ozone hole in south spring months. Look at line 2 for each. Is this correct interpretation?
Second, tropics I guess is lower because of sun angle is more direct having a shorter path length through ozone layer. That does not seem quite correct as due to temperature and effect of earth spin atmosphere is thicker at equator, but perhaps that is secondary effect. Basically at 20km altitude air pressure is close to same at poles and equator. Sorry my ignorance I am EE but worked decades in atmospheric sciences so I likely have some misunderstandings of atmospheric science.
Regards
Patrick Grant
Thanks for your comments. At first sight the uvi does look about the same in both hemispheres, but that’s only because the latitudinal gradients are so steep. If you look closely you’ll see that the contours are displaced towards higher values in the south. The uvi is indeed more intense at the equator because of the more direct path through the absorbing ozone (also because there’s less of it).
The gradients in density are, as you suspected, only secondary effects.