HR: 1340h
AN: A33A-0132    [Abstracts]
TI: Evaluation of OMI Pre-launch Radiometric Calibration Using In-flight Data
AU: Cebula, R P
AF: Science Systems and Applications, Inc., 10210 Greenbelt Rd., Lanham, MD 20706
AU: * Jaross, G
EM: jaross@qhearts.gsfc.nasa.gov
AF: Science Systems and Applications, Inc., 10210 Greenbelt Rd., Lanham, MD 20706
AU: Dobber, M
AF: KNMI, P.O. Box 201, De Bilt, 3730 AE Netherlands
AU: Taylor, S L
AF: Science Systems and Applications, Inc., 10210 Greenbelt Rd., Lanham, MD 20706
AU: Oord, B v
AF: KNMI, P.O. Box 201, De Bilt, 3730 AE Netherlands
AU: Kowalewski, M
AF: Science Systems and Applications, Inc., 10210 Greenbelt Rd., Lanham, MD 20706
AU: Dirksen, R
AF: KNMI, P.O. Box 201, De Bilt, 3730 AE Netherlands
AB: The Ozone Monitoring Instrument (OMI) launched aboard the EOS Aura satellite on 15 July 2004 is intended as the successor to the Total Ozone Mapping Spectrometer (TOMS) operated by NASA over the past 25 years. OMI uses hyperspectral sensors, has improved horizontal resolution, and an expanded wavelength range (270-500 nm). Thus its capabilities extend well beyond those of TOMS. In addition to the traditional TOMS products (column ozone, surface reflectance, aerosol index, UV surface flux), OMI will generate multiple additional products (ozone profile and tropospheric column; trace gases important to ozone chemistry and air quality; cloud fraction and height) using for some the spectroscopic structure of the backscattered Earth radiances. Calibration requirements for spectroscopy differ significantly from those for TOMS-like products, yet all must be met in order to achieve the expected data product quality. We use both traditional engineering (``hard'') and science data-based (``soft'') calibration techniques to assess OMI's initial on-orbit performance and evaluate the accuracy of its pre-launch calibration. Several techniques have been developed over the years to assess the calibration accuracy of backscatter ultraviolet sensors. Among these are comparisons with solar irradiance reference spectra and radiances measured over Antarctica and Greenland. Retrieved reflectances over the open ocean and cloud tops, and radiance residuals from column ozone retrievals also provide verification of radiometric calibrations. We present initial results of these verifications, which we use to evaluate the accuracy of the radiometric calibration provided at launch. We also assess the impact of observed calibration errors on the various OMI products, realizing that these errors will decrease as the OMI calibration is refined.
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting