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| Titel |
Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia |
| VerfasserIn |
I. B. Konovalov, E. V. Berezin, P. Ciais, G. Broquet, M. Beekmann, J. Hadji-Lazaro, C. Clerbaux, M. O. Andreae, J. W. Kaiser, E.-D. Schulze |
| 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 ; 14, no. 19 ; Nr. 14, no. 19 (2014-10-01), S.10383-10410 |
| Datensatznummer |
250119074
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| Publikation (Nr.) |
 copernicus.org/acp-14-10383-2014.pdf |
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| Zusammenfassung |
| A method to constrain carbon dioxide (CO2) emissions from
open biomass burning by using satellite observations of co-emitted
species and a chemistry-transport model (CTM) is proposed and
applied to the case of wildfires in Siberia. CO2 emissions
are assessed by means of an emission model assuming a direct
relationship between the biomass burning rate (BBR) and the fire
radiative power (FRP) derived from MODIS measurements. The key
features of the method are (1) estimating the FRP-to-BBR conversion
factors (α) for different vegetative land cover types by
assimilating the satellite observations of co-emitted species into
the CTM, (2) optimal combination of the estimates of α
derived independently from satellite observations of different
species (CO and aerosol in this study), and (3) estimation of
the diurnal cycle of the fire emissions directly from the FRP
measurements. Values of α for forest and grassland fires in
Siberia and their uncertainties are estimated using the Infrared
Atmospheric Sounding Interferometer (IASI)
carbon monoxide (CO) retrievals and MODIS aerosol optical depth
(AOD) measurements combined with outputs from the CHIMERE mesoscale
chemistry-transport model. The constrained CO emissions are
validated through comparison of the respective simulations with
independent data of ground-based CO measurements at the ZOTTO
site. Using our optimal regional-scale estimates of the conversion
factors (which are found to be in agreement with earlier
published estimates obtained from local measurements of experimental
fires), the total CO2 emissions from wildfires in Siberia in
2012 are estimated to be in the range from 280 to 550 Tg C,
with the optimal (maximum likelihood) value of
392 Tg C. Sensitivity test cases featuring different
assumptions regarding the injection height and diurnal variations of
emissions indicate that the derived estimates of the total
CO2 emissions in Siberia are robust with respect to
the modeling options (the different estimates vary within less than
15% of their magnitude). The CO2 emission
estimates obtained for several years are compared with independent
estimates provided by the GFED3.1 and GFASv1.0 global emission
inventories. It is found that our "top-down" estimates for
the total annual biomass burning CO2 emissions in the period
from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger
than the respective bottom-up estimates; these discrepancies cannot
be fully explained by uncertainties in our estimates. There are also
considerable differences in the spatial distribution of
the different emission estimates; some of those differences have
a systematic character and require further analysis. |
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