Ammonia emissions in the United States, European Union, and China derived by high-resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3)

Authors

F. Paulot, Harvard UniversityFollow
D. J. Jacob, Harvard University
J. O. Bash, U.S. EPA Office of Research and Development, Research Triangle Park, North Carolina
K. Travis, Harvard University
D. K. Henze, University of Colorado Boulder

Document Type

Article

Date of this Version

2014

Citation

Paulot, F., D. J. Jacob, R. W. Pinder, J. O. Bash, K. Travis, and D. K. Henze (2014), Ammonia emissions in the United States, European Union, and China derived by high-resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3), J. Geophys. Res. Atmos., 119, 4343–4364, doi:10.1002/2013JD021130.

Comments

This article is a U.S. government work, and is not subject to copyright in the United States.

Abstract

We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimize ammonia (NH₃) emissions in the U.S., European Union, and China by inversion of 2005–2008 network data for NH⁺₄ wet deposition fluxes. Optimized emissions are derived on a 2◦ × 2.5◦ grid for individual months and years. Error characterization in the optimization includes model errors in precipitation. Annual optimized emissions are 2.8 Tg NH₃−Na⁻¹ for the contiguous U.S., 3.1 Tg NH₃−Na⁻¹ for the European Union, and 8.4 Tg NH₃−Na−1 for China. Comparisons to previous inventories for the U.S. and European Union show consistency (∼±15%) in annual totals but some large spatial and seasonal differences. We develop a new global bottom-up inventory of NH₃ emissions (Magnitude And Seasonality of Agricultural Emissions model for NH₃ (MASAGE_NH₃)) to interpret the results of the adjoint optimization. MASAGE_NH₃ provides information on the magnitude and seasonality of NH3 emissions from individual crop and livestock sources on a 0.5◦ × 0.5◦ grid. We find that U.S. emissions peak in the spring in the Midwest due to corn fertilization and in the summer elsewhere due to manure. The seasonality of European emissions is more homogeneous with a well-defined maximum in spring associated with manure and mineral fertilizer application. There is some evidence for the effect of European regulations of NH3 emissions, notably a large fall decrease in northern Europe. Emissions in China peak in summer because of the summertime application of fertilizer for double cropping