Upper-Tropospheric Ammonia Detected from AIRS

Warner et al. (2017) provided evidence of substantial increases in atmospheric ammonia (NH₃) concentrations (14-year) over several of the world’s major agricultural regions, using recently available retrievals from the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. These data are currently distributed at NASA GES DISC. The main sources of atmospheric NH₃ are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use; rates of emission are also sensitive to climate change. It is difficult to retrieve geophysical properties of a thin layer of a constituent (e.g., upper tropospheric, UT, NH₃) above strong sources near the earth’s surface from a nadir-view sensor and in the thermal spectral regions. We have developed a technique to obtain such a product with good accuracy. We will show strong UT NH₃ signals over Asian summer monsoon regions that are comparable to those observed by MIPAS (Höpfner et al., 2016) for the year 2008 where MIPAS data was available. However, AIRS provides high UT NH₃ concentration in the Asian summer monsoon regions in all years from 2002 through 2018. We will also show UT NH₃ signals due to biomass burning emissions.

Key words: Ammonia, Upper Troposphere, AIRS

References

Höpfner, M., Volkamer, R., Grabowski, U., Grutter, M., Orphal, J., Stiller, G., von Clarmann, T., and Wetzel, G.: First detection of ammonia (NH₃) in the Asian summer monsoon upper troposphere, Atmos. Chem. Phys., 16, 14357-14369, https://doi.org/10.5194/acp-16-14357-2016, 2016.