Initial Applications of the New Cross-Track Infrared Sounder (CrIS) Satellite Observations of Ammonia

Ammonia (NH₃) is essential for agricultural activities and is one of the most important reactive nitrogen species in any ecosystem. Reactive nitrogen is an essential nutrient to plants, a limiting element for growth in many ecosystems, and can come from different nitrogen compounds in the atmosphere. However, in excess it can have harmful effects such as soil acidification (Galloway et al., 2003), water eutrophication (i.e. algae blooms) (Bergstrom et al., 2006), changes to vegetation types, and biodiversity loss (e.g. Fenn et al., 2010; Sheppard et al., 2011). Ammonia reacts quickly in the atmosphere with acidic species to produce a significant fraction of fine mode particulate matter (PM_2.5), which is associated with smog and adverse effects on the environment and human health. Emissions of ammonia from anthropogenic activities have largely been unregulated globally, and it is the only PM_2.5 precursor that is both currently increasing (Warner et al., 2017) and projected to continue to increase throughout the next century globally (e.g. Paulot et al., 2013) due to increased demand for more and better food (e.g. more livestock production, greater use of fertilizer for crops), especially in developing countries. Despite all this, there are still large uncertainties in our knowledge of the sources and spatiotemporal distributions of NH₃ at regional and global scales. However, recent satellite observations are providing a greater understanding of its emission sources, atmospheric transport, and deposition. Presented here are initial applications from the derived CrIS Fast Physical Retrieval (CFPR) NH₃ satellite observations (Shephard and Cady-Pereira, 2015). These initial CFPR derived applications include: (i) the monitoring and transport of NH₃ concentrations across North America, (ii) air quality model (e.g. GEM-MACH) evaluations, such as investigating the contributions of different sources to ambient ammonia in the Athabasca Oil Sands and north-western Canada, with a newly implemented bidirectional flux scheme (Whaley et al., 2017), and an initial evaluation of the spatiotemporal NH₃ emission profiles used in the model, (iii) computing the dry deposition flux of reactive nitrogen from ammonia across North America (Kharol et al., 2017), (iv) deriving ammonia emissions (e.g. Fort McMurray fires) from the CrIS observations (e.g. Shephard et al., 2017), and (v) the first assimilation exercise constraining NH₃ emissions in north-western Europe.

References

Bergstrom, A. –K., and M. Jansson (2006), Atmospheric nitrogen deposition has caused nitrogen enrichment and eutrophication of lakes in the northern hemisphere, Global Change Biology, 12, 635-643, doi:10.1111/j.1365-2486.2006.01129.x.

Fenn, M. E., E. B. Allen, S. B. Weiss, S. Jovan, L. H. Geiser, G. S. Tonnesen, R. F. Johnson, L. E. Rao, B. S. Gimeno, F. Yuan, T. Meixner, and A. Bytnerowicz (2010), Nitrogen critical loads and management alternatives for N-impacted ecosystems in California, J. Environ. Manage., 91, 2404–2423, doi:10.1016/j.jenvman.2010.07.034, 2010.

Galloway, J. N., J. D. Aber, J. W. Erisman, S. P. Seitzinger, R. W. Howarth, E. B. Cowling, and B. J. Cosby (2003), The nitrogen cascade, Bioscience, 53, 341–356.

Kharol, S. K., M. W. Shephard, C. A. McLinden, L. Zhang, C. E. Sioris, J. M. O’Brien, R. Vet, K. E. Cady-Pereira, J. Siemons, and N. A. Krotkov, Satellite observations of reactive nitrogen (Nr) dry deposition over North America, submitted to GRL, 2017.

Paulot, F., D. J. Jacob, and D. K. Henze (2013), Sources and processes contributing to nitrogen deposition: an adjoint model analysis applied to biodiversity hotspots worldwide, Environ. Sci. Technol., 47, 3226-3233.

Shephard, M. W. and K. E. Cady-Pereira, Cross-track Infrared Sounder (CrIS) Satellite Observations of Tropospheric Ammonia, Atmos. Meas. Tech., 8, 1323–1336, doi:10.5194/amt-8-1323-2015, 2015.

Shephard, M. W., C. A. McLinden, S. K. Kharol, C. E. Sioris, K. E. Cady-Pereira, and V. Fioletov, Satellite Observations of Reactive Nitrogen from Fires in Fort McMurray, in preparation for ACP, 2017.

Sheppard, L. J., I. D. Leith, T. Mizunuma, J. N. Cape, A. Crossley, S. Leeson, M. A. Sutton, N. van Dijk, and D. Fowler (2011), Dry deposition of ammonia gas drives species change faster than wet deposition of ammonium ions: evidence from a long-term field manipulation, Global Change Biology, 17, 3589-3607, doi:10.1111/j.1365-2486.2011.02478.x.

Warner, J. X., R. R. Dickerson, Z. Wei, L. L. Strow, Y. Wang, and Q. Liang (2017), Increased atmospheric ammonia over the world’s major agricultural areas detected from space, Geophys. Res. Lett., 44, doi:10.1002/2016GL072305.

Whaley, C., P. Makar, M. W. Shephard, L. Zhang, J. Zhang, Q. Zheng, A. Akingunola, G. Wentworth, J. Murphy, S. K. Kharol, and K. E. Cady-Pereira, Contributions of natural and anthropogenic sources to ambient ammonia in the Athabasca Oil Sands and north-western Canada, submitted to ACP, 2017.