Stratospheric Aerosol and Gas Experiment III (SAGE III)
SAGE III was successfully launched onboard a Meteor-3M spacecraft on December 10, 2001 at 17:18:57 UTC from the Baikonur Cosmodrome in Kazakhstan. The satellite is in a sun-synchronous orbit with an ascending node time of about 9 AM. Routine measurement operations began in March 2002. The Meteor-3M mission, along with the SAGE III mission, was terminated on March 6, 2006, because of a power supply system failure resulting in loss of communication with the satellite.
The Meteor-3M spacecraft is an advanced model of the Meteor spacecraft that was developed over 30 years ago. The payload includes SAGE III and other instruments designed to measure temperature and humidity profiles, clouds, surface properties, and high energy particles in the upper atmosphere. Please see the SAGE III Instrument page for further technical details.
SAGE III's role in the EOS program is to provide global, long-term measurements of key components of the Earth's atmosphere. The most important of these are the vertical distribution of aerosols and ozone from the upper troposphere through the stratosphere.
In addition, SAGE III also provides unique measurements of temperature in the stratosphere and mesosphere and profiles of trace gases such as water vapor and nitrogen dioxide that play significant roles in atmospheric radiative and chemical processes.
The primary scientific objective of the three SAGE III missions is to obtain high quality, global measurements of key components of atmospheric composition (See Table of Measurements) and their long-term variability.
These measurements are vital inputs to the global scientific community for improved understanding of climate, climate change, and human-induced ozone trends.
The specific measurement objectives of SAGE III provide 1 km vertical resolution profiles of: aerosols and clouds at seven wavelengths from the mid-troposphere into the stratosphere and where appropriate, the mesosphere; O3 from the mid-troposphere to 85 km; H2O from the planetary boundary layer to 50 km; NO2 from the tropopause to 45 km; NO3 from 20 to 55 km; OClO from 15 to 25 km; and, O2 from the mid-troposphere to 70 km.