Three-dimensional distribution of anthropogenic and natural aerosols over France measured using TROPOMI satellite observations during the ACROSS campaign
Authors: Maheshwarkar Prem , Cuesta Juan , Formenti Paola , Yu Chenjie , Lemmouchi Farouk , Cantrell Christopher 
Published: February 2023

ACROSS is an extensive field campaign that was conducted over the greater Paris region in summer 2022 to study the interaction between the urban pollution plume and biogenic volatile organic compounds emitted from the surrounding forests. This is mainly done by synergism of in-situ ground-based and airborne observations of the composition of the atmosphere (Cantrell and Michoud, 2022). Satellite observations are complementary to these measurements, providing a regional and continental framework of the atmospheric composition.In this study, we present new satellite observations of the 3D distribution of anthropogenic and natural atmospheric aerosols over France during the ACROSS campaign. For this, we use a so-called AEROS5P approach which derives vertical profiles of aerosol extinction for each cloud free TROPOspheric Monitoring Instrument (TROPOMI) pixel using hyperspectral top of atmosphere (TOA) reflectance measurements in the visible and near infrared. This method uses a priori knowledge on particle properties, such as their size and refractive index, along with meteorological parameters from meteorological analyses (ECMWF), surface albedo properties, and a unique a priori aerosol vertical profile. The initial version of AEROS5P was able to monitor the 3D distribution of biomass burning aerosols over Australia, which is a single aerosol type (Lemmouchi et al., 2022).In this study, we present a new version of AEROS5P for deriving the 3D distribution of several aerosol types present in the same atmospheric scene, from both anthropogenic and natural origins. This is done by taking for each TROPOMI pixel the co-localised aerosol type from the VIIRS aerosol product and then processing it with an associated aerosol model of microphysical and optical properties. These aerosol properties are taken from an AERONET sun photometer inversion climatology (Dubovik et al., 2002). This new multi aerosol type AEROS5P method is used for studying dust transport from North Africa, urban pollution from the Paris region, and smoke aerosol transport from South France during the ACROSS campaign. These results are compared against total aerosol extinction from MODIS, vertical aerosol backscatter from CALIOP, airborne and ground-based measurements of aerosol composition, optical and microphysical properties performed in the framework of ACROSS.ReferencesCantrell, Christopher, and Vincent Michoud. "An Experiment to Study Atmospheric Oxidation Chemistry and Physics of Mixed Anthropogenic&#8211;Biogenic Air Masses in the Greater Paris Area." Bulletin of the American Meteorological Society 103.8 (2022): 599-603.Dubovik, Oleg, et al. "Variability of absorption and optical properties of key aerosol types observed in worldwide locations." Journal of the atmospheric sciences 59.3 (2002): 590-608Lemmouchi, Farouk, et al. "Three-Dimensional Distribution of Biomass Burning Aerosols from Australian Wildfires Observed by TROPOMI Satellite Observations." Remote Sensing 14.11 (2022): 2582.&#160;