The stratosphere extends from 12km's to 50km's above the earths surface. The ozone layer ranges from 15km to 35km. What scientists have been and still are working out, are the chemical reactions that take place in this ozone layer.
Scientists are finding more and more things out with time and this builds up a whole picture of the stratosphere in chemical terms and more things can then be found out.
Scientists have to analyse the air by using various types of spectroscopic techniques. The reason why these work so effectively is because a lot of these species that are found in the stratosphere are able to absorb radiations in the range of the ultra violet and Infrared. We know this due to the ozone filtering a lot of harmful rays from the sun. In a sample, the concentration of ozone can be found by calculating the absorption level. To receive accurate results from this and to make assumptions, the samples have to be taken varying all the factors. For example, in different places around the earth and at different altitudes and also at different times through the year. These measurements would then be taken every so often to keep a record and notice any changes.
The way of measuring the absorption rate can be done by using helium balloons, from high altitude planes and also satellites.
When scientists are analysing the ozone, they need to consider which species absorb solar radiation, the wavelength of the radiation absorbed and the strengh of the absorption. They also need to find out what happens when radiation has been absorbed. The absorbed energy may be lost by collision with other molecules, or by radiation or it may cause the molecule to fragment or to react directly with another species. It is also good information if they know how fast each reaction takes place. Special techniques have been developed for the short lived radicals which react extremely quick. Here is an example of a fast reaction:.