First Detection of Ammonia in the Upper Troposphere

Typography

Population is growing, climate is warming – hence, emission of ammonia (NH3) trace gas from e.g. agriculture will increase worldwide. Recently, scientists of Karlsruhe Institute of Technology (KIT) for the first time detected NH3 in the upper troposphere. Together with researchers from Colorado/USA and Mexico, they analyzed satellite measurements by the MIPAS infrared spectrometer and found increased amounts of NH3 between 12 and 15 km height in the area of the Asian monsoon. This suggests that the gas is responsible for the formation of aerosols, smallest particles that might contribute to cloud formation. The researchers present their work in the Atmospheric Chemistry and Physics journal. (DOI: 10.5194/acp-16-14357-2016)

Population is growing, climate is warming – hence, emission of ammonia (NH3) trace gas from e.g. agriculture will increase worldwide. Recently, scientists of Karlsruhe Institute of Technology (KIT) for the first time detected NH3 in the upper troposphere. Together with researchers from Colorado/USA and Mexico, they analyzed satellite measurements by the MIPAS infrared spectrometer and found increased amounts of NH3 between 12 and 15 km height in the area of the Asian monsoon. This suggests that the gas is responsible for the formation of aerosols, smallest particles that might contribute to cloud formation. The researchers present their work in the Atmospheric Chemistry and Physics journal. (DOI: 10.5194/acp-16-14357-2016)

Ammonia, a chemical compound of nitrogen and hydrogen, mainly originates from agricultural processes, in particular from lifestock farming and fertilization. Wide application of ammonia as a basic substance of fertilizers became possible by the development of artificial ammonia synthesis in Karlsruhe more than 100 years ago. Today, highest ammonia emissions are encountered in North India and Southeast China. Due to population growth and global warming, global ammonia emissions are expected to increase strongly in the future. Gaseous ammonia reacts with acids, such as sulfuric acid or nitric acid, to the corresponding ammonium salts. However, ammonia does not only pollute the ecosystems. Particles of ammonium salts can attach to each other and form aerosol particles acting as condensation nuclei in cloud formation. Such aerosols of anthropogenic origin have a cooling effect in the atmosphere and might compensate part of the anthropogenic greenhouse effect.

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 Figure: Michael Höpfner / KIT