TOMS/ADEOS instrument characterization

Data sets from the total ozone mapping spectrometer (TOMS) on the ADEOS I spacecraft have been processed using initial and time-dependent instrument characterizations. Initial characterizations, performed on the ground, focused on wavelength registration of the six near-UV TOMS channels and on the instrument albedo calibration. Few calibration adjustments were required in the postlaunch phase. Instrument performance, including bandpass wavelengths, were stable throughout the life of the instrument. Indirect evidence exists for small changes in the reflectance of the primary solar diffuser. Characterizations used in data processing assume no change. No ozone retrieval errors are expected due to this assumption. All totaled, estimated calibration uncertainties represent less than 1% in total column ozone uncertainty. A comparison between two TOMS instruments is marginally consistent with these estimates. However, a comparison with ground measurements resulted in differences exceeding 1%.