ULIRS, an optimal estimation retrieval scheme for carbon monoxide using IASI spectral radiances: sensitivity analysis, error budget and simulations

Illingworth, SM; Remedios, John J; Boesch, H; Moore, David P; Sembhi, H; Dudhia, A; Walker, Joanne C

Abstract

This paper presents a new retrieval scheme for tropospheric carbon monoxide (CO), using measured radiances from the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp-A satellite. The University of Leicester IASI Retrieval Scheme (ULIRS) is an optimal estimation retrieval scheme, which utilises equidistant pressure levels and a floating pressure grid based on topography. It makes use of explicit digital elevation and emissivity information, and incorporates a correction for solar surface reflection in the daytime with a high resolution solar spectrum. The retrieval scheme has been assessed through a formal error analysis, via the simulation of surface effects and by an application to real IASI data over a region in Southern Africa. The ULIRS enables the retrieval of between 1 and 2 pieces of information about the tropospheric CO vertical profiles, with peaks in the sensitivity at approximately 5 and 12 km. Typical errors for the African region relating to the profiles are found to be ~20% at 5 and 12 km, and on the total columns to range from 18 to 34%. Finally the performance of the ULIRS is shown for a range of simulated geophysical conditions.

Citation

Illingworth, S., Remedios, J. J., Boesch, H., Moore, D. P., Sembhi, H., Dudhia, A., & Walker, J. C. (2011). ULIRS, an optimal estimation retrieval scheme for carbon monoxide using IASI spectral radiances: sensitivity analysis, error budget and simulations. Atmospheric Measurement Techniques, 4, 269-288. https://doi.org/10.5194/amt-4-269-2011

• Journal Article Type: Article
• Acceptance Date: Feb 2, 2011
• Online Publication Date: Feb 11, 2011
• Publication Date: 2011
• Deposit Date: Feb 15, 2021
• Publicly Available Date: Feb 16, 2021
• Journal: Atmospheric Measurement Techniques
• Print ISSN: 1867-1381
• Publisher: European Geosciences Union
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Pages: 269-288
• DOI: https://doi.org/10.5194/amt-4-269-2011
• Public URL: http://researchrepository.napier.ac.uk/Output/2736527