Monday, 11 January 2016
Hall D/E ( New Orleans Ernest N. Morial Convention Center)
Fire CO2 fluxes play a major role in the terrestrial biosphere, the global carbon budget, and the long-term carbon cycling of fire-prone ecosystems. African fires account for roughly 50% of global fire carbon (C) fluxes, largely emitted into the atmosphere as CO2 and CO. Disentangling fire CO2 emissions from total CO2 and CO fluxes remains a challenge, due to large uncertainties in combusted biomass density and combustion efficiency (CO2:CO). Major savanna and grassland ecosystems fire events during the OCO-2 era provide ideal case studies for testing current understanding of African fire C emissions. We use MOPITT CO to characterize the role of fire CO2 enhancements in OCO-2 CO2 measurements during September-October 2014. We constrain the combustion efficiency of southern Africa fires by retrieving CO2:CO total dry-column CO2 concentrations from OCO-2 and MOPITT total dry-column CO. We also performed a benchmark OSSE, based on the CMS-Flux atmospheric transport and chemistry analysis of CO2 and CO. We find that OCO-2 MOPITT CO2:CO (1:30) are almost a factor of 2 higher than the OSSE true and retrieved CO2:CO values (1:18 and 1:16). Our findings indicate that southern Africa fire CO2:CO values are higher than previously assumed. We hypothesize that the higher-than-expected CO2:CO values are due to fire fuel dryness and composition. We anticipate that CO2:CO observations will provide an important global constraint on the estimation and attribution of continental-scale CO2 fluxes and on the processes controlling fire C emission variability.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner