Validation of 12 years (2008–2019) of IASI-A CO with IAGOS aircraft observations
Résumé
IASI-A, IASI-B and IASI-C (Infrared Atmo- spheric Sounding Interferometer) are nadir-looking thermal- infrared sensors which have monitored the atmospheric com- position since 2008. Atmospheric carbon monoxide (CO) is retrieved from IASI radiances with two algorithms: the SOft- ware for a Fast Retrieval of IASI Data (SOFRID) and Fast Optimal Retrievals on Layers for IASI (FORLI). Airborne in situ observations from the In-service Aircraft for a Global Observing System (IAGOS) European research infrastruc- ture have been used to validate IASI CO retrievals. The vali- dation study of IASI CO data performed in 2011 with IAGOS data was limited to two airports (Frankfurt and Windhoek) and 2 years because of the limited sampling at the other IA- GOS sites. The extension of the IAGOS infrastructure during the last decade has enabled validation with enough temporal sampling at 33 airports worldwide over the whole IASI-A period (2008–2019).
The retrievals provide between 1.5 and 3 independent pieces of information about the CO vertical profile, and we have chosen to validate the surface–600hPa and 600– 200 hPa partial columns in addition to the total column. The ability of the retrievals to capture the CO variabilities is slightly different for the two retrieval algorithms. The cor- relation coefficients for the time series are generally larger for SOFRID, especially for the total and lower-tropospheric columns, meaning a better representation of the phase of the variability, while the amplitudes of the variations of FORLI are in better agreement with IAGOS in the middle to upper troposphere.
Domaines
Sciences de l'environnementOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
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