Sensitivity of global CO simulations to uncertainties in biomass burning sources

We investigate the sensitivity of simulated CO in the Unified Chemistry Transport Model ( UCTM) to several biomass burning emissions, including four bottom-up and two top-down inventories. We compare the sensitivity experiments with observations from MOPITT, surface and airborne NOAA Global Monitoring Division network data, and the TRACE-P field campaign.

The variation of the global annual emissions of these six biomass burning inventories is within 30%; however, their regional variations are often much higher ( factor of 2 - 5). These uncertainties translate to about 6% variation in the global simulated CO but more than a 100% variation in some regions. The annual mean CO variation is greater in the Southern Hemisphere (> 12%) than in the Northern Hemisphere (< 5%), largely because biomass burning is a higher percentage of the total source in the Southern Hemisphere.