Envisat witnesses return of the South Polar ozone hole   The animation represents the ozone forecast between 1 September to 9 September, showing 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. The dark blue represents regions with less than 200 DUs.   This graph compares this year's new-born ozone hole - represented by dots - with those of previous years, in terms of area, in millions of square kilometres on the vertical axis and time duration, on the horizontal axis. The hole is defined as a thickness of ozone that is less than 200 Dobson Units (DUs). The information on this chart comes from ten years of ESA satellite observations, first from the Global Ozone Monitoring Experiment (GOME) instrument on ERS-2, and now from its successor, Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), on 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. Envisat results to be revealed     Envisat is a truly advanced Earth observation satellite with a unique combination of sensors to vastly improve the range and accuracy of scientific measurements of the atmosphere, oceans, land surface and ice. Its total range of capabilities far exceed those of any previous or planned Earth observation satellite. It was launched in spring 2002 by an Ariane-5 launcher. Release date: 1 September 2004