The Royal Metorological Institute of Belgium has a long tradition with the observation of ozone in the atmosphere. In 1969 (and even somewhat earlier), well before the commotion about the ozone hole caused by anthropogenic emissions of Chlorofluorocarbons (CFCs), a series of measurements of the vertical profiles of ozone was started with the launch of ozonesondes on weather balloons. A few years later, in 1971, a time series of almost daily observations of the total column of ozone was initiated with the installation of a Dobson spectrophotometer.

In the early days the idea behind the ozone observations was to improve weather forecasts. Ozone mainly resides at high altitudes (20-25km), and therefore contains information on the large scale circulations in the atmosphere. However, after the detection of the ozone hole in the mid 1980s, and the awareness that depletions of the ozone layer could cause enhanced levels of UV radiation with possible damage to different forms of life on Earth, monitoring the thickness of the ozone layer and the vertical distribution of the ozone concentrations became crucial. 

Nowadays, the recovery of the ozone layer and the interaction with the climate change is widely studied, as well as the role of tropospheric ozone as a greenhouse gas and an important component in air quality investigations.

Here, we provide some information about the formation and destruction of ozone in the atmosphere, describe the formation and evolution of the ozone hole at the poles, present a short summary of techniques for measuring ozone, and finally present the Uccle ozone measurements and their time series assessment.