Dry deposition of NO2 over China inferred from OMI columnar NO2 and atmospheric chemistry transport model

Abstract The NO 2 dry deposition over China was estimated based on an inferential model, in which the surface NO 2 concentrations and deposition velocities were derived from OMI columnar NO 2 and the simulation results from atmospheric chemistry transport models. Nationally, the annual NO 2 dry deposition fluxes ranged from 0.0005 to 8.54 kg N ha −1 , with an average of 0.48 kg N ha −1 . The total NO 2 dry deposition over China was 0.46 Tg N yr −1 , mainly contributed by northern and southeast China. Due to contrary seasonal trends of the NO 2 concentrations (high in cold months) and deposition velocities (high in warm months), the estimated NO 2 dry depositions did not show strong seasonal pattern, instead showing relatively high values from August to October and low ones in February. The annual NO 2 dry deposition has an increasing trend from 2007 to 2014, with the highest deposition level achieved in 2011. This research conducts a thorough validation between estimated NO 2 dry depositions with ground measurements of NO 2 concentrations and provides an objective spatial perspective and insight on the existing NO 2 dry deposition maps in China.