Impact of Infrared Atmospheric Sounding Interferometer (IASI) thermal infrared measurements on global ozone reanalyses
<p>The information content of thermal infrared measurements for tropospheric ozone (O<span class="inline-formula"><sub>3</sub></span>) estimation has already been well demonstrated. However, the impact of such measurements to constrain modelled O<span class...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-10-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/14/6291/2021/gmd-14-6291-2021.pdf |
| Summary: | <p>The information content of thermal infrared measurements for tropospheric ozone (O<span class="inline-formula"><sub>3</sub></span>) estimation has already been well demonstrated. However, the impact of such measurements to constrain modelled O<span class="inline-formula"><sub>3</sub></span> distributions within global assimilation systems is not yet unequivocal. A new tropospheric O<span class="inline-formula"><sub>3</sub></span> reanalysis is computed for the year 2010 by means of assimilating measurements from the Infrared Atmospheric Sounding Interferometer (IASI) within the MOdéle pour la Chimie Á Grande Echelle (MOCAGE) chemical transport model. The objective is to evaluate the impact of recent methodological improvements of the data assimilation scheme on the O<span class="inline-formula"><sub>3</sub></span> distribution. The new O<span class="inline-formula"><sub>3</sub></span> reanalysis (named IASI-r) and its precursor (IASI-a) have been validated against ozonesondes, and compared to independent estimations of tropospheric O<span class="inline-formula"><sub>3</sub></span> and to results from two state-of-the-art products based on detailed tropospheric chemistry (the Goddard Earth Observing System with a coupled chemistry–climate model, GEOS-CCM, and the Copernicus Atmosphere Monitoring Service, CAMS, reanalysis). The main difference between IASI-r and IASI-a concerns the treatment of IASI observations, with radiances being assimilated directly in IASI-r instead of intermediate Level 2 O<span class="inline-formula"><sub>3</sub></span> retrievals. IASI-r is found to correct major issues with IASI-a, such as the neutral or negative impact of IASI assimilation in the extra-tropics and the presence of residual biases in the tropics. IASI-r also compares relatively well to the CAMS reanalysis, which is based on a more comprehensive chemical mechanism and the assimilation of several ultraviolet (UV) and microwave measurements.</p> |
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| ISSN: | 1991-959X 1991-9603 |