Ozone in the stratosphere is the Earth's natural shield for the damaging UV radiation from the sun. However, ozone is also an air pollutant when it is close to the surface (smog) and an important greenhouse gas when it is around the tropopause.

In our division we measure ozone using satellites and ground-based instruments. On the basis of satellite ozone measurements we provide UV forecasts on the TEMIS website.

Satellite measurements of ozone
The satellite spectrometers OMI, SCIAMACHY, GOME-2 can measure the atmospheric ozone content by measuring the spectrum of ultraviolet sunlight that is reflected by the earth's atmosphere. We make the following ozone data products: total ozone, ozone profiles, and assimilated total ozone. Data can be found on the TEMIS website.

Grondbased measurements of ozone
The Brewer spectrophotometer measures ultraviolet sunlight at 6 wavelengths between 302 and 320 nm. The extinction of sunlight by ozone varies hugely with wavelength in this part of the spectrum. From these measurements the total ozone content of the atmosphere above De Bilt is computed. If direct sunlight is available, the accuracy of the measurements should be better than 2%. In cloudy conditions the accuracy is somewhat lower. Measurements are performed automatically during daytime hours. We are currently operating Brewer MKIII, #189. Yesterday's and today's measurements can be found here.
An ozone sonde is a balloon borne instrument that measures ozone concentration in situ between the ground and 32 km altitude. So typically 90% of theatmospheric ozone is measured. Ozone sondes are launched at least once a week, but more are launched when we expect unusual atmospheric conditions. Additional sondes are also launched for satellite validation. The most recent data can be found here.