SAGE III EOS

This paper describes the SAGE III (Stratospheric Aerosol and Gas Experiment III) experiments as part of the EOS program for long term monitoring of the atmospheric ozone and aerosol for global change study. SAGE III carries the heritage from the previous sensors SAM II, SAGE I, and SAGE II, which have provided stratospheric and tropospheric measurements of key atmospheric species such as aerosol, ozone, nitrogen dioxide, and water vapor. In addition to those atmospheric species, SAGE III will measure profiles of temperature, pressure, chlorine dioxide, and nitrogen trioxide using the solar and lunar occultation techniques. Three SAGE III instruments will be launched between 1999 and 2002. The First SAGE III will be on a Russian Meteor 3M spacecraft to be launched in 1999. The second SAGE III will be on the Space Station in 2002. The third SAGE III instrument is for a Flight of Opportunity, most probably will be flying in an inclined orbit for global coverage in 2001. The mission's science objectives, in terms of providing global measurements of key species for climate change study, and the algorithms used to retrieve the geophysical information from the measurements will be discussed.