As noted above, ozone is mostly concentrated between 11 and 40 km altitude; it shows
large seasonal and, mostly, latitude variation. Because of its high altitude
location, its lines are narrow: at 25 km, , hence
, is reduced by
a factor of 20 with respect to see level; moreover, the dipole moment of ozone
(
= 0.53 D), 3.5 times smaller than that of H2O, further reduces the ozone
line widths.
Because of their small widths and despite the small ozone abundance,
ozone lines have significant peak opacities, especially
above 230 GHz (
).