Retrieval of xCO 2 from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON

High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval o...

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Bibliographic Details
Published in:Atmospheric Measurement Techniques
Main Authors: M. Buschmann, N. M. Deutscher, V. Sherlock, M. Palm, T. Warneke, J. Notholt
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2016
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Online Access:https://doi.org/10.5194/amt-9-577-2016
https://doaj.org/article/b8f2532392e4429fae8c1c9b1b1e5964
Description
Summary:High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO 2 (denoted by xCO 2 ). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average.