Modeling observed aerosols and contrail ice crystals with a microphysics code

Abstract. Contrails contribute significantly to the climate impact of aviation; however, their formation depends on fuel composition, engine type and meteorological conditions and current contrail formation models may be insufficiently constrained by observations. Here we revisit the 1D microphysics code MoMiE and compare its results with recent contrails measurements from the ECLIF and NEOFUELS/VOLCAN campaigns. The sensitivity of the model to different Fuel Sulfur Contents (FSC), from 0.5 to 195 ppmm, and to different engine combustion modes, i.e. lean-burn, intermediate and rich-burn, is studied, as well as to the emission index of organic compounds and ions, and to ambient temperature and relative humidity. For the first time, the recent NEOFUELS/VOLCAN data of total number of particles measured in the near-field are compared to model simulations. Adjusting the input parameters within their expected uncertainty ranges allows the model to approximate the data for different fuels and soot regimes, demonstrating a clear sensitivity to organic compounds. The model results are also compared to far-field measurements of ice crystals of ECLIF and NEOFUELS/VOLCAN. MoMiE generally captures the dependence of contrail ice crystals to non-volatile particle emissions and compares well with the measurements in the soot-rich regime. In the soot-poor regime, MoMiE results depend mainly on the ambient temperature and show little variability obtained for different FSCs. These results emphasize the need for further investigation on the role of the different parameters involved in the contrail formation, as well as the need for further measurements of the different plume components.