Self-consistent retrieval of MLT pressure/temperature and CO2 densities from SABER/TIMED limb radiances in the 15 and 4.3 μm channels
Abstract
SABER/TIMED broadband infrared limb observations of the mesosphere and lower thermosphere (MLT) are providing important information about the temperature, composition and energy budget of this atmospheric region. Prior to the current processing using the v2.0 algorithm, pressure and temperature were retrieved using radiances measured in the 15 μm CO2 band in combination with the WACCM model CO2 distribution. The v2.0 operational processing uses a rigorous non-LTE, self consistent, two-channel, simultaneous retrieval of pressure, temperature and CO2 density from SABER daytime broadband limb 15 and 4.3 μm radiances. Three years of simultaneous temperature/CO2 profiles have been produced thus far in a post processing mode where the two-channel methodology is applied to radiances that have been registered in altitude space. Results from these retrievals for various latitudes and seasons as well as their comparisons with model results are discussed. The line-by-line radiative transfer calculations and iterations that must be performed for the retrieval are very time consuming. An optimized version of the algorithm, that greatly increases the processing speed needed for large data volumes, has been developed that uses a look-up-table (LUT) technique. This general approach has been successfully applied for many years to process lower atmosphere observations based on the LTE assumption. We have adapted this method for SABER simultaneous temperature/CO2 processing by applying an empirical orthogonal function (EOF) technique to generate a database of independent atmospheric profiles on which the LUT retrieval technique operates. The technique also has been configured for application in the non-LTE MLT environment. This report presents an overview of the work to provide an efficient multi-channel, non-LTE MLT limb retrieval technique suitable for processing the large volume of data collected by SABER/TIMED over its nearly 12-year highly successful mission.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMSA51A2072K
- Keywords:
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- 1640 GLOBAL CHANGE Remote sensing;
- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0340 ATMOSPHERIC COMPOSITION AND STRUCTURE Middle atmosphere: composition and chemistry;
- 3360 ATMOSPHERIC PROCESSES Remote sensing