Air-borne glyoxal measurements in the marine and continental atmosphere – comparison to TROPOMI satellite data and EMAC model simulations

This study presents glyoxal observations of the mini-DOAS instrument performed during seven different airborne campaigns (ACRIDICON-CHUVA (2014), OMO (2015), EMeRGe-EU (2017), EMeRGe-Asia (2018), CoMet (2018), CAFE (2018), and SouthTRAC (2019)) from the German HALO (High Altitude and LOng range) research aircraft. Geographic regions covered by the research missions include the southern tip of South America, the Weddell sea and the Western Antarctic Peninsula, the tropical and subtropical Atlantic, Europe, as well as the East China Sea, the Philippines, and Japan. The studied areas thus covered observations over (i) natural source regions of glyoxal and its precursors, (ii) local as well as regional pollution sources i.e. biomass burning and major anthropogenic activities, and (iii) the remote marine and terrestrial background atmosphere. Using simultaneous measurements of horizontally (Limb) and vertically (Nadir) aligned telescopes, atmospheric concentrations and vertical column densities (VCDs) of glyoxal along the flight tracks are inferred. For validation purposes, these air-borne measurements are compared to collocated observations of the TROPOspheric Monitoring Instrument (TROPOMI). Overall, a reasonable agreement among the two data sets is found. Finally, both measurements are compared to simulations of the global ECHAM/MESSy Atmospheric Chemistry (EMAC) model (*), which provide further insights into the different sources and sinks of glyoxal and its precursors as well as into its photochemistry.

(*) See also the presentation of Rosanka et al., entitled ‘Improving the representation of glyoxal in the global EMAC model using TROPOMI retrievals and air-borne campaign data’.