Effects of heterogeneous reactions on tropospheric chemistry: a global simulation with the chemistry–climate model CHASER V4.0

Abstract. This study uses a chemistry–climate model CHASER (MIROC) to explore the roles of heterogeneous reactions (HRs) in global tropospheric chemistry. Three distinct HRs N2O5, HO2, and RO2 are considered for surfaces aerosols cloud particles. The simulation is verified with EANET EMEP stationary observations; R/V Mirai ship-based data; ATom1 aircraft measurements; satellite observations by OMI, ISCCP, CALIPSO-GOCCP; reanalysis data JRA55. chemistry facilitates improvement performance respect NO2, OH, CO, O3, especially lower troposphere. calculated effects cause marked changes abundances O3 (−2.96 %), NOx (−2.19 CO (+3.28 mean CH4 lifetime (+5.91 %). These were contributed mostly N2O5 uptake onto middle At surface, HO2 gives largest contributions, particularly significant effect North Pacific region (−24 % +68 NOx, +8 −70 OH), mainly attributable its clouds. reaction has small contribution, but negative on not negligible. In general, uptakes ice crystals droplets that occur radicals smaller than aerosol-uptake (+1.34 lifetime, +1.71 −0.56 +0.63 abundances). Nonlinear responses OH found same modeling framework this (R>0.93). Although all showed tendencies levels, HR(HO2) abundance increment an increasing loss rate. However, positive tendency turns reduction at higher rates (>5 times). Our results demonstrate affect only polluted areas also remote such as mid-latitude sea boundary layer upper Furthermore, can bring challenges pollution efforts because it causes opposite between (increase) surface (decrease).