Chinese Academy of Meteorological Sciences
Ammonia (NH3) is the most abundant alkaline gas in the atmosphere and the only source of particulate NH4+, playing an important role in the formation of secondary inorganic salts. NH3 can easily react with nitric acid (HNO3) and sulfuric acid (H2SO4) in the atmosphere to form secondary inorganic aerosols such as ammonium nitrate (NH4NO3) and ammonium sulfate ((NH4)2SO4). Therefore, the emission, transportation, and chemical transformation of NH3 have an important impact on the spatial and temporal distribution of global inorganic aerosols. In this paper, the atmospheric NH3 concentration observed by the Michelson interferometer (MIPAS) on ENVISAT satellite and the AIRS detector on Aqua satellite, as well as simulated by the global atmospheric chemistry climate model EMAC, are used to analyze the spatial distribution characteristics of atmospheric NH3 in East Asia from June to September in 2008-2011. The results show that the highest concentration of NH3 near the surface appears in northern India, and deep convection exists in the Bay of Bengal near northern India in summer. The upward transport column of NH3 appears over northern India and the Qinghai-Tibet Plateau. Although NH3 has a short lifetime, it can be transported to the upper troposphere and lower stratosphere (UTLS) in the deep convection region. During the Asian summer monsoon, the location of the anticyclone dominates the spatial distribution of NH3 in the UTLS. The location of the Asian summer monsoon anticyclone dominates the spatial distribution of NH3 in the UTLS area. The high concentration center of NH3 continues to exist in the anticyclone. The position of the high concentration center of NH3 corresponds well to the position of the center of the anticyclone, and there exist one or two NH3 high concentration centers, indicating that the change of the circulation pattern in the anticyclone has an important influence on the distribution of NH3 in the anticyclone.