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| Titel |
FTIR time-series of biomass burning products (HCN, C2H6, C2H2, CH3OH, and HCOOH) at Reunion Island (21° S, 55° E) and comparisons with model data |
| VerfasserIn |
C. Vigouroux, T. Stavrakou, C. Whaley, B. Dils, V. Duflot, C. Hermans, N. Kumps, J.-M. Metzger, F. Scolas, G. Vanhaelewyn, J.-F. Müller, D. B. A. Jones, Q. Li, M. Mazière |
| 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 ; 12, no. 21 ; Nr. 12, no. 21 (2012-11-07), S.10367-10385 |
| Datensatznummer |
250011571
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| Publikation (Nr.) |
 copernicus.org/acp-12-10367-2012.pdf |
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| Zusammenfassung |
| Reunion Island (21° S, 55° E), situated in the Indian Ocean
at about 800 km east of Madagascar, is appropriately located to
monitor the outflow of biomass burning pollution from Southern Africa and
Madagascar, in the case of short-lived compounds, and from other Southern
Hemispheric landmasses such as South America, in the case of longer-lived
species. Ground-based Fourier transform infrared (FTIR) solar absorption
observations are sensitive to a large number of biomass burning products. We
present in this work the FTIR retrieval strategies, suitable for very humid
sites such as Reunion Island, for hydrogen cyanide (HCN), ethane
(C2H6), acetylene (C2H2), methanol (CH3OH), and
formic acid (HCOOH). We provide their total columns time-series obtained from
the measurements during August–October 2004, May–October 2007, and May
2009–December 2010. We show that biomass burning explains a large part of
the observed seasonal and interannual variability of the chemical species.
The correlations between the daily mean total columns of each of the species
and those of CO, also measured with our FTIR spectrometer at Reunion Island,
are very good from August to November (R ≥ 0.86). This allows us to
derive, for that period, the following enhancement ratios with respect to CO:
0.0047, 0.0078, 0.0020, 0.012, and 0.0046 for HCN, C2H6,
C2H2, CH3OH, and HCOOH, respectively. The HCN ground-based
data are compared to the chemical transport model GEOS-Chem, while the data
for the other species are compared to the IMAGESv2 model. We show that using
the HCN/CO ratio derived from our measurements (0.0047) in GEOS-Chem reduces
the underestimation of the modeled HCN columns compared with the FTIR
measurements. The comparisons between IMAGESv2 and the long-lived species
C2H6 and C2H2 indicate that the biomass burning emissions
used in the model (from the GFED3 inventory) are probably underestimated in
the late September–October period for all years of measurements, and
especially in 2004. The comparisons with the short-lived species,
CH3OH and HCOOH, with lifetimes of around 5 days, suggest
that the emission underestimation in late September–October 2004, occurs
more specifically in the Southeastern Africa-Madagascar region. The very good
correlation of CH3OH and HCOOH with CO suggests that, despite the
dominance of the biogenic source of these compounds on the global scale,
biomass burning is their major source at Reunion Island between August and
November. |
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