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| Titel |
Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor |
| VerfasserIn |
R. Checa-Garcia, J. Landgraf, A. Galli, F. Hase, V. A. Velazco, H. Tran, V. Boudon, F. Alkemade, A. Butz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 9 ; Nr. 8, no. 9 (2015-09-08), S.3617-3629 |
| Datensatznummer |
250116569
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| Publikation (Nr.) |
 copernicus.org/amt-8-3617-2015.pdf |
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| Zusammenfassung |
| Sentinel-5 (S5) and its precursor (S5P) are future European
satellite missions aiming at global monitoring of methane
(CH4) column-average dry air mole fractions
(XCH4). The spectrometers to be deployed onboard the
satellites record spectra of sunlight backscattered from the Earth's
surface and atmosphere. In particular, they exploit CH4
absorption in the shortwave infrared spectral range around
1.65 μm (S5 only) and 2.35 μm (both S5 and
S5P) wavelength. Given an accuracy goal of better than 2 % for
XCH4 to be delivered on regional scales, assessment and
reduction of potential sources of systematic error such as
spectroscopic uncertainties is crucial. Here, we investigate how
spectroscopic errors propagate into retrieval errors on the global
scale. To this end, absorption spectra of a ground-based Fourier
transform spectrometer (FTS) operating at very high spectral
resolution serve as estimate for the quality of the spectroscopic
parameters. Feeding the FTS fitting residuals as a perturbation into
a global ensemble of simulated S5- and S5P-like spectra at relatively
low spectral resolution, XCH4 retrieval errors exceed
0.6 % in large parts of the world and show systematic correlations
on regional scales, calling for improved spectroscopic parameters. |
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