Improved OMI BrO and OClO algorithms and BrO validation
Abstract
We present improved operational algorithms and data products for OMI BrO and OClO. The algorithms are, as before, based on the direct fitting of radiances. BrO is fitted from 317.0-347.5 nm, within the UV-2 channel of OMI, while OClO is fitted from 358.5.5-392.0 nm, in the visible channel. The model that is fitted to the measurements consists of the solar reference, attenuated by contributions from the target gas and interfering gases, rotational Raman scattering, additive and multiplicative closure polynomials and a common mode spectrum. The common mode spectra (one per cross-track position, computed on-line) are the average of several hundred fitting residuals and include any instrument effects that are unrelated to molecular scattering and absorption cross sections. The BrO retrieval uses albedo and wavelength-dependent air mass factors (AMFs), which have been pre-computed using climatological BrO profiles. The wavelength-dependent AMF is applied pre-fit to the BrO cross-sections, and the spectral fit retrieves vertical column densities directly. For OClO only slant column is provided. Flagging for the OMI row anomaly is now included in the products. Ground-based comparisons (Harestua, Lauder, Barrow, and Fairbanks) in addition to model comparison for stratospheric component are presented.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A13F0432S
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0340 ATMOSPHERIC COMPOSITION AND STRUCTURE / Middle atmosphere: composition and chemistry;
- 0394 ATMOSPHERIC COMPOSITION AND STRUCTURE / Instruments and techniques