Ozone simulations and observations (e.g. CCMI, SBUV etc)

There is a huge effort to predict the future development of stratospheric ozone under different scenarios. These scenarios are modelled in different groups with different model setups/different boundary/initial conditions. In order to get a robust prediction many different model runs can be combined into ensembles. Model runs of total ozone often don’t have same absolute values and are therefore normalized using satellite observations of ozone data. A date can then be picked at which the ozone of all the models agrees with the measured ozone. Only then they can be compared. For a more robust prediction of the behaviour of future ozone an average of all the model realizations can be produced to make a multi model mean so that a more robust prediction can be made.