Carbon Dioxide as an Indicator of Biogenic Activity and Biomass Burning Emissions in the Southeast United States
Wednesday, 17 December 2014
The NASA SEAC4RS mission (utilizing the NASA DC-8 in August-September 2013) was intended to give a broad survey of the atmospheric composition of the southeastern United States including emissions from vegetation, biomass burning and anthropogenic activity. Carbon dioxide in conjunction with other gas-phase and aerosol tracers can be used to differentiate these sources. Isoprene emissions were heavily dependent on vegetation type and temperature, with largest emissions over deciduous forests in Southeastern Missouri. Carbon dioxide uptake, however, was less dependent on vegetation type and more dependent on time of year with largest uptake in August. Emissions of other volatile organic compounds will be analyzed based on land use classification and meteorological conditions. For periods with strong biomass burning influence, variations in emissions are studied with respect to source fuel (from land use imagery) and combustion efficiency (from in situ CO and CO2 measurements). Agricultural fires (in the Mississippi River Valley) were found to have lower combustion efficiencies than wildfires indicating smoldering conditions. This resulted in higher particulate emissions & lower single scattering albedos.