Improving the quantification of carbonaceous aerosols over megacities by satellite

Abstract

<p>The processes that lead to the formation of carbonaceous aerosols, organic carbon and black carbon, in the atmosphere are related to trace gases. We focus here on the statistical links between organic and black carbon with satellite-observable trace gases (CO, NO2, O3, HCHO and SO2). A preliminary study (Deroubaix et al, in preparation for ACP) has shown that half of the variability of carbonaceous aerosols can be linked to these trace gases in the plumes of megacities. This result is studied in more detail by focusing on megacities to estimate the surface concentrations of carbonaceous aerosols.</p> <p>Based on specific megacities for which measurements of organic carbon and black carbon concentrations are available, we propose a methodology to estimate black carbon and organic carbon concentrations using AERONET AOD and TROPOMI satellite retrievals (tropospheric column density of CO, HCHO, NO2, O3 and SO2). This estimation is analyzed for several megacities by comparing it to global air quality forecasts made at NCAR and ECMWF. Finally, we discuss how this estimation of black and organic carbon over megacities is modified when replacing the AERONET AOD with the VIIRS satellite AOD.</p>