Ozone Monitoring Instrument (OMI) is a Dutch-Finnish ozone monitoring imaging spectrometer that is designed to provide accurate measurements of total column ozone, ozone profile, surface UV irradiance, aerosols and cloud characteristics, and the column amounts of trace gases SO<sub>2</sub>, NO<sub>2</sub>, HCHO, BrO, and OClO at high spatial resolution. The OMI along with the three other instruments, the Microwave Limb Sounder (MLS), the High Resolution Dynamics Limb Sounder (HIRDLS), and the Tropospheric Emission Spectrometer (TES), will be flown on the NASA’s Aura mission in early 2004. The standard atmospheric chemistry and dynamics products derived from OMI, MLS, and HIRDLS will be archived at the NASA's GES DAAC (TES data products will be archived at NASA Langley Research Center DAAC) and will be freely available to the public. Highlights of OMI data products, as well as their availability, distribution and data support are discussed in this paper.
The absolute radiometric calibration of the NS001 Thematic Mapper Simulator reflective channels was examined based on laboratory tests and in-flight comparisons to ground measurements. The NS001 data are calibrated in-flight by reference to the NS001 internal integrating sphere source. This source's power supply or monitoring circuitry exhibited greater instability in-flight during 1988-1989 than in the laboratory. Extrapolating laboratory behavior to in-flight data resulted in 7-20 percent radiance errors relative to ground measurements and atmospheric modeling. Assuming constancy in the source's output between laboraotry and in-flight resulted in generally smaller errors. Upgrades to the source's power supply and monitoring circuitry in 1990 improved its in-flight stability, though in-flight ground reflectance based calibration tests have not yet been performed.