Ozone hole, as seen with Envisat

A forecast of September 2004's emerging ozone hole, as seen by ESA's Envisat environmental satellite. Ozone forecasting is available based on near-real time observations from the Envisat instrument Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), which are inputted into a data assimilation program which provides near-real time ozone fields for today and a forecast for the coming days. The forecast is available through a project called Tropospheric Emission Monitoring Internet Service (TEMIS). The image represents ozone thickness in Dobson Units (DUs), which stands for the total thickness of ozone in a given vertical column if it were concentrated into a single slab at standard temperature and atmospheric pressure – 400 DUs is equivalent to a thickness of four millimetres, for example.