Top-down isoprene emissions over Africa based on TROPOMI HCHO data

The top-down emissions are inferred from an inverse modelling scheme built on the chemistry-transport model MAGRITTEv1.1 and its adjoint (Müller et al., 2019; Bauwens et al., 2016; Müller and Stavrakou, 2005), constrained by TROPOMI NO2 (van Geffen et al., 2022) and HCHO (De Smedt et al., 2018) column data through a joint inversion. This accounts for the intricate interplay between NOx and VOCs through the chemical feedbacks of the HOx-NOx-VOC system, by relying on a concomitant use of HCHO and NO2 satellite observations in order to simultaneously optimize both VOC and NOx emissions (Opacka et al., 2025).