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| Titel |
Long-term tropospheric formaldehyde concentrations deduced from ground-based fourier transform solar infrared measurements |
| VerfasserIn |
N. B. Jones, K. Riedel, W. Allan, S. Wood, P. I. Palmer, K. Chance, J. Notholt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 18 ; Nr. 9, no. 18 (2009-09-24), S.7131-7142 |
| Datensatznummer |
250007652
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| Publikation (Nr.) |
 copernicus.org/acp-9-7131-2009.pdf |
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| Zusammenfassung |
| We report a 13-year (1992–2005) dataset of total column measurements of
formaldehyde (HCHO) over Lauder, New Zealand, inferred from solar infrared
spectra measured using a high-resolution Fourier Transform Spectrometer
(FTS). Ambient HCHO concentrations at this rural location are often close to
levels typical of remote marine environments (<250 ppt), which are close
to the detection limit using standard techniques. Consequently we develop a
new method that successfully produces HCHO columns with sufficient
sensitivity throughout the whole season. HCHO columns over Lauder have a
strong seasonal cycle (±50%), with a mean column of 4.9×1015 molecules cm−2,
peaking during summer months. A simple box model of
CH4 oxidation reproduces the observed broad-scale seasonal cycle, but
significantly underestimates the seasonal peak HCHO ground concentrations
during summer. This suggests the existence of an additional significant
source of HCHO, possibly isoprene that cannot be explained by oxidation of
CH4 alone. The ground-based FTS column data compare well with
collocated HCHO column measurements from the Global Ozone Monitoring
Experiment (GOME) satellite instrument during the operational period of GOME
(1996–2001, r2=0.65, mean bias=10%, n=48). |
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