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| Titel |
Climate variability and trends in biogenic emissions imprinted on satellite observations of formaldehyde from SCIAMACHY and OMI sounders |
| VerfasserIn |
Trissevgeni Stavrakou, Jean-Francois Müller, Maite Bauwens, Isabelle De Smedt, Michel Van Roozendael |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141882
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| Publikation (Nr.) |
 EGU/EGU2017-5436.pdf |
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| Zusammenfassung |
| Biogenic hydrocarbon emissions (BVOC) respond to temperature, photosynthetically active
radiation, leaf area index, as well as to factors like leaf age, soil moisture, and ambient
CO2 concentrations. Isoprene is the principal contributor to BVOC emissions and
accounts for about half of the estimated total emissions on the global scale, whereas
monoterpenes are also significant over boreal ecosystems. Due to their large emissions,
their major role in the tropospheric ozone formation and contribution to secondary
organic aerosols, BVOCs are highly relevant to both air quality and climate. Their
oxidation in the atmosphere leads to the formation of formaldehyde (HCHO) at high
yields. Satellite observations of HCHO abundances can therefore inform us on the
spatial and temporal variability of the underlying sources and on their emission
trends.
The main objective of this study is to investigate the interannual variability and trends of
observed HCHO columns during the growing season, when BVOC emissions are dominant,
and interpret them in terms of BVOC emission flux variability. To this aim, we use the
MEGAN-MOHYCAN model driven by the ECMWF ERA-interim meteorology to calculate
bottom-up BVOC fluxes on the global scale (Müller et al. 2008, Stavrakou et al. 2014) over
2003-2015, and satellite HCHO observations from SCIAMACHY (2003-2011) and
OMI (2005-2015) instruments (De Smedt et al. 2008, 2015). We focus on mid- and
high-latitude regions of the Northern Hemisphere in summertime, as well as tropical
regions taking care to exclude biomass burning events which also lead to HCHO
column enhancements. We find generally a very strong temporal correlation (>0.7)
between the simulated BVOC emissions and the observed HCHO columns over
temperate and boreal ecosystems. Positive BVOC emission trends associated to
warming climate are found in almost all regions and are well corroborated by the
observations.
Furthermore, using OMI HCHO observations over 2005-2015 as constraints in an
inversion based on the adjoint of the IMAGESv2 chemistry-transport model (Bauwens et al.
2016), we derive top-down biogenic emissions, which exhibit stronger emission trends than
the bottom-up inventory at high-latitude regions of the Northern Hemisphere, suggesting that
the response of biogenic emissions to warming temperature might be stronger than currently
assumed in models. |
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