I should maybe also mention that I asked Gunnar Myrhe for references which substantiate the "folklore",
I cited here:

>At 10 km (top of the troposphere) virtually all radiation below 290 nm has been absorbed. All radiation below 100 nm is absorbed in the thermosphere above 100 km. O2 absorbs strongly at wavelengths between 100 and 200 nm and also in a weaker band between 200 and 245 nm. O2 absorptions attenuate incoming UV radiation of less than 200 nm above an altitude of 50 km. Light of wavelengths of between 200 and 300 nm is strongly absorbed in the stratosphere by ozone (O3) and transmission of radiation of wavelengths less than 290 nm is negligible below 10 km. Between 300 and 800 nm the stratosphere is only weakly absorbing and most of the solar radiation at these wavelengths is transmitted into the troposphere. There is little tropospheric absorption below 600 nm but H2O and CO2, at high tropospheric concentrations, deplete the near IR part of the incoming solar flux appreciably. Hence, surface solar irradiance is dominated by visible wavelengths.

(In my former academic surrounding things which appear uncited in lecture notes were called "folklore", i.e. those were facts which were usually proven and justified many, many times)
I mostly wanted to get a look into the measurement methods, which lead to the above assertions and be able to judge about possible simplifications which sometimes takes place in educational material.

Like now Jan Galkowski just pointed to an article which I can't access but which seems to talk about large circulations of ozone into tropospheric layers.

>The downward transport of stratospheric ozone is an important natural source of tropospheric ozone, particularly in the upper troposphere, where changes in ozone have their largest radiative effect.

![ozone circulation](http://www.nature.com/ngeo/journal/v7/n5/images/ngeo2138-f1.jpg)