Envisat observes resurgent ozone hole   Chlorine activation over the South Pole during 25 September 2003 as obtained from MIPAS measurements, shown by volume mixing ratio.   An image of the ozone hole over the South Pole after splitting in two on 25 September 2002, acquired from GOME data. Ozone 'thickness' is measured in Dobson Units.   Ozone hole over the South Pole during 25 September 2003 monitored by MIPAS. Ozone 'thickness' is measured in Dobson Units.   Comparative ozone hole areas for the years 2000 to present, using GOME data and MIPAS data for this year. Note the sudden decline of the blue 2002 line in late September, corresponding to the ozone hole split.   Envisat is an 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.   MetOp will be Europe's first operational polar-orbiting weather satellite. It will replace one of two satellite services operated by the United States National Oceanic and Atmospheric Administration (NOAA). Release date: 11 June 2004