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| Titel |
Regional-scale correlation between CO2 fire emissions, burned areas, and mid-tropospheric CO2 diurnal variations retrieved from MetOp-A/ATOVS observations (2007-2011) over southern Africa. |
| VerfasserIn |
Nicolas Meilhac, Cyril Crevoisier, Alain Chédin, Noëlle A. Scott, Raymond Armante, Laurent Crépeau |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080529
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| Zusammenfassung |
| Inferred from the Advanced TIROS Operational Vertical Sounder (ATOVS) flying onboard
the MetOp-A platform, mid-tropospheric CO2 columns are retrieved from evening (21:30
LST) and morning (09:30 LST) observations over the tropic for the period July 2007 -
December 2011, using a non linear inference scheme based on neural networks
initially designed for TOVS instruments onboard the NOAA platforms (Chédin et al.
2003),
We find that the difference between evening and morning CO2 columns, hereafter
referred to as Daily Tropospheric Excess (DTE), increases up to several ppm over regions
affected by biomass fires, confirming the results obtained from TOVS observations onboard
the NOAA10 platform over 1987-1991. The physical mechanism linking DTE with fire
emissions comes from the diurnal cycle of fire emissions associated with enhanced
convection: hot convective fire plumes injects CO2 into the troposphere during the
afternoon peak of fire activity, which is seen by the satellite evening passing; it is
then diluted by large scale atmospheric transport, before the next satellite morning
passing.
The CO2 DTE shows monthly, seasonal and annual spatial patterns similar to fire
products, such as CO2 emissions from the Global Fire Emission Database (GFEDv3) and
burned areas from the MODIS instrument for ten regions of southern Africa with contrasted
vegetation cover. Across these regions, a high positive correlation is found between DTE and
CO2 emission (R2 ~ 0.8). There is also a good agreement in terms of seasonal variability
north of 14S. South of 14S, the seasonal increase of the CO2 difference during the early fire
season starts earlier and rises up more rapidly than in either GFEDv3 or MODIS burned
areas. This misfit could come from limitations in current burned area detection algorithms
owing in particular to their difficulty in detecting small fires associated with small burnt scars. |
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