Methane retrievals from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared measurements: performance comparison of proxy and physics retrieval algorithms
We compare two conceptually different methods for determining methane column-averaged mixing ratios from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared (SWIR) measurements. These methods account differently for light scattering by aerosol and cirrus. The proxy method retrieves a CO2...
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| Hauptverfasser: | , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
30 May 2012
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| In: |
Journal of geophysical research. Atmospheres
Year: 2012, Jahrgang: 117 |
| ISSN: | 2169-8996 |
| DOI: | 10.1029/2012JD017549 |
| Online-Zugang: | Verlag, Volltext: http://dx.doi.org/10.1029/2012JD017549 Verlag, Volltext: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2012JD017549 
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| Verfasserangaben: | D. Schepers, S. Guerlet, A. Butz, J. Landgraf, C. Frankenberg, O. Hasekamp, J.-F. Blavier, N.M. Deutscher, D.W.T. Griffith, F. Hase, E. Kyro, I. Morino, V. Sherlock, R. Sussmann, and I. Aben |
| Zusammenfassung: | We compare two conceptually different methods for determining methane column-averaged mixing ratios from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared (SWIR) measurements. These methods account differently for light scattering by aerosol and cirrus. The proxy method retrieves a CO2 column which, in conjunction with prior knowledge on CO2acts as a proxy for scattering effects. The physics-based method accounts for scattering by retrieving three effective parameters of a scattering layer. Both retrievals are validated on a 19-month data set using ground-based at 12 stations of the Total Carbon Column Observing Network (TCCON), showing comparable performance: for the proxy retrieval we find station-dependent retrieval biases from −0.312% to 0.421% of a standard deviation of 0.22% and a typical precision of 17 ppb. The physics method shows biases between −0.836% and −0.081% with a standard deviation of 0.24% and a precision similar to the proxy method. Complementing this validation we compared both retrievals with simulated methane fields from a global chemistry-transport model. This identified shortcomings of both retrievals causing biases of up to 1ings and provide a satisfying validation of any methane retrieval from space-borne SWIR measurements, in our opinion it is essential to further expand the network of TCCON stations. |
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| Beschreibung: | Gesehen am 14.01.2019 |
| Beschreibung: | Online Resource |
| ISSN: | 2169-8996 |
| DOI: | 10.1029/2012JD017549 |