Quantifying Fluxes of Greenhouse Gases in Baltimore-Washington Metropolitan Area from Airborne Measurements

We quantify fluxes of CO2, CH4 and CO from various emission sources in the Baltimore-Washington metropolitan area using airborne in-situ measurements, obtained during the February 2015 Fluxes of Greenhouse Gases in Maryland (FLAGG-MD) campaign. In this study, we focus on the attribution of enhanced signals of CO2, CH4, and CO to various emission sources in the region, including point (power plants, landfill, coal mines), area (Baltimore city, Washington DC), and mobile sources by making use of the NOAA HYSPLIT air parcel trajectory model as well as the analysis of chemical ratios. The Brown Station landfill in Maryland was found to be a major source of methane. The flux of each attributed compound is then estimated using a mass balance approach, and results are compared to various sources of emission data, such as CEMS, CarbonTracker, FFDAS, and ODIAC. Finally, the uncertainty of aircraft-based mass balance approach is quantified by conducting a sensitivity analysis of calculated flux to such factors as PBL height, wind direction and speed, interpolation methods, and background concentration.