Acetylene (C<sub>2</sub>H<sub>2</sub>) and hydrogen cyanide (HCN) from IASI satellite observations: global distributions, validation, and comparison with model
We present global distributions of C<sub>2</sub>H<sub>2</sub> and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008–2010. These distributions are obtained with a fast method allowing to retrieve C<s...
| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/15/10509/2015/acp-15-10509-2015.pdf |
| Summary: | We present global distributions of C<sub>2</sub>H<sub>2</sub> and hydrogen cyanide (HCN) total columns derived
from the Infrared Atmospheric Sounding Interferometer (IASI) for the years
2008–2010. These distributions are obtained with a fast method allowing to
retrieve C<sub>2</sub>H<sub>2</sub> abundance globally with a 5 % precision and HCN abundance
in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data
are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show
that there is an overall agreement between the ground-based and space
measurements with correlation coefficients for daily mean measurements
ranging from 0.28 to 0.81, depending on the site. Global C<sub>2</sub>H<sub>2</sub> and
subtropical HCN abundances retrieved from IASI spectra show the expected
seasonality linked to variations in the anthropogenic emissions and seasonal
biomass burning activity, as well as exceptional events, and are in good
agreement with previous spaceborne studies. Total columns simulated by the
Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are
compared to the ground-based FTIR measurements at the four selected stations.
The model is able to capture the seasonality in the two species in most of
the cases, with correlation coefficients for daily mean measurements ranging
from 0.50 to 0.86, depending on the site. IASI measurements are also compared
to the distributions from MOZART-4. Seasonal cycles observed from satellite
data are reasonably well reproduced by the model with correlation
coefficients ranging from −0.31 to 0.93 for C<sub>2</sub>H<sub>2</sub> daily means, and from
0.09 to 0.86 for HCN daily means, depending on the considered region.
However, the anthropogenic (biomass burning) emissions used in the model seem
to be overestimated (underestimated), and a negative global mean bias of 1 %
(16 %) of the model relative to the satellite observations was found for
C<sub>2</sub>H<sub>2</sub> (HCN). |
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| ISSN: | 1680-7316 1680-7324 |