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Titel |
Remote sensing of CO2 and CH4 using solar absorption spectrometry with a low resolution spectrometer |
VerfasserIn |
C. Petri, T. Warneke, N. Jones, T. Ridder, J. Messerschmidt, T. Weinzierl, M. Geibel, J. Notholt |
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 ; 5, no. 7 ; Nr. 5, no. 7 (2012-07-12), S.1627-1635 |
Datensatznummer |
250003004
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Publikation (Nr.) |
copernicus.org/amt-5-1627-2012.pdf |
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Zusammenfassung |
Throughout the last few years solar absorption Fourier Transform Spectrometry
(FTS) has been further developed to measure the total columns of CO2
and CH4. The observations are performed at high spectral resolution,
typically at 0.02 cm−1. The precision currently achieved is generally
better than 0.25%. However, these high resolution instruments are quite
large and need a dedicated room or container for installation. We performed
these observations using a smaller commercial interferometer at its maximum
possible resolution of 0.11 cm−1. The measurements have been performed
at Bremen and have been compared to observations using our high resolution
instrument also situated at the same location. The high resolution instrument
has been successfully operated as part of the Total Carbon Column Observing
Network (TCCON). The precision of the low resolution instrument is
0.32% for XCO2 and 0.46% for XCH4. A comparison of the
measurements of both instruments yields an average deviation in the retrieved
daily means of ≤0.2% for CO2. For CH4 an average bias between
the instruments of 0.47% was observed. For test cases, spectra recorded by
the high resolution instrument have been truncated to the resolution of
0.11 cm−1. This study gives an offset of 0.03% for CO2 and
0.26% for CH4. These results indicate that for CH4 more than 50%
of the difference between the instruments results from the resolution
dependent retrieval. We tentatively assign the offset to an incorrect
a-priori concentration profile or the effect of interfering gases, which may
not be treated correctly. |
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