Analysis of atmospheric ammonia over South and East Asia based on the MOZART-4 model and its comparison with satellite and surface observations

Abstract. Limited availability of atmospheric ammonia (NH3) observations limits our understanding controls on its spatial and temporal variability interactions with the ecosystem. Here we used Model for Ozone Related chemical Tracers version 4 (MOZART-4) global chemistry transport model Hemispheric Transport Air Pollution 2 (HTAP-v2) emission inventory to simulate NH3 distribution year 2010. We presented a first comparison monthly averaged satellite distributions limited ground-based available across South Asia. The MOZART-4 simulations over Asia East were evaluated retrievals obtained from Infrared Atmospheric Sounding Interferometer (IASI) 69 monitoring stations air quality 32 Nationwide Nitrogen Deposition Monitoring Network (NNDMN) China. identified northern region India (Indo-Gangetic Plain, IGP) as hotspot in Asia, both using observations. In general, close agreement was found between yearly total columns simulated by IASI measurements IGP, (r=0.81), North China Plain (NCP), (r=0.90). However, MOZART-4-simulated column substantially higher than compared retrievals, which show smaller differences. Model-simulated surface concentrations indicated all seasons measured although uncertainties remain measurements. Overall, showed comparable emissions, indicating rapid dissipation due secondary aerosol formation, can be explained larger emissions acidic precursor gases