Estimating CO2 emissions for the Greater Toronto Area using Orbiting Carbon Observatory 3 (OCO-3) observations and high resolution modeling

Dense population and intense human activities (such as commercial and residential development, transportation and industry) have made large cities hotspots for anthropogenic carbon dioxide (CO2) emissions. Accurate estimation of CO2 emissions from urban areas can provide critical insights for climate mitigation policies. NASAs Orbiting Carbon Observatory-3 (OCO-3) instrument, launched in May 2019 to the International Space Station, is equipped with a unique Pointing Mirror Assembly (PMA). The PMA allows scanning of snapshot area maps (SAMs) over a localized area of interest such as a city. Here, the XCO2 observations collected by OCO-3 SAM mode over the Greater Toronto Area are compared with the ground-based remote sensing measurements. XCO2 variations across the city, simulated by a high-resolution atmospheric model (GEM-MACH), are presented and the simulated values are compared with the OCO-3 observations as a step toward inferring information about CO2 emissions.