PMC Particle Sizes Derived from Aura OMI Observations
Abstract
The Ozone Monitoring Instrument (OMI) on the Aura satellite has been observing PMCs since December 2004. The OMI cloud detection algorithm uses backscattered UV measurements at multiple wavelengths between 267-292 nm. This information provides the opportunity to determine characteristic PMC particle sizes using the Angstrom exponent derived from the cloud brightness. OMI pixels are moderate in size (13 km x 48 km at nadir), so there will be some spatial averaging relative to a higher resolution measurement such as CIPS data from AIM, although the spatial resolution is significantly better than comparable SBUV measurements (170 km x 170 km). The wide cross-track coverage of OMI (2000 km swath) is useful for observing a large portion of the PMC region during a single orbit, and for observing the same location on up to seven consecutive orbits. We now have 8 years of Southern Hemisphere PMC observations from OMI through the 2011-2012 season. Useful Northern Hemisphere PMC observations from OMI are limited to the first four years of operation (2005-2008) due to an instrument scattered light issue that developed during the mission. We will present an evaluation of OMI measurements to understand what particle size information can be determined over different spatial and temporal scales. We will also look at the variability implied by these data in the context of long-term PMC trend results from similar measurements by SBUV instruments over 34 years.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMSA21A2098D
- Keywords:
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- 0340 ATMOSPHERIC COMPOSITION AND STRUCTURE / Middle atmosphere: composition and chemistry