Letter abstract


Nature Geoscience 2, 479 - 483 (2009)
Published online: 21 June 2009 | doi:10.1038/ngeo551

Subject Category: Atmospheric science

Global ammonia distribution derived from infrared satellite observations

Lieven Clarisse1, Cathy Clerbaux2, Frank Dentener3, Daniel Hurtmans1 & Pierre-François Coheur1

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Global ammonia emissions have more than doubled since pre-industrial times, largely owing to agricultural intensification and widespread fertilizer use1. In the atmosphere, ammonia accelerates particulate matter formation, thereby reducing air quality. When deposited in nitrogen-limited ecosystems, ammonia can act as a fertilizer. This can lead to biodiversity reductions in terrestrial ecosystems, and algal blooms in aqueous environments2, 3, 4, 5, 6, 7, 8. Despite its ecological significance, there are large uncertainties in the magnitude of ammonia emissions, mainly owing to a paucity of ground-based observations and a virtual absence of atmospheric measurements3, 8, 9, 10, 11. Here we use infrared spectra, obtained by the IASI/MetOp satellite, to map global ammonia concentrations from space over the course of 2008. We identify several ammonia hotspots in middle–low latitudes across the globe. In general, we find a good qualitative agreement between our satellite measurements and simulations made using a global atmospheric chemistry transport model. However, the satellite data reveal substantially higher concentrations of ammonia north of 30° N, compared with model projections. We conclude that ammonia emissions could have been significantly underestimated in the Northern Hemisphere, and suggest that satellite monitoring of ammonia from space will improve our understanding of the global nitrogen cycle.

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  1. Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
  2. UPMC Univ. Paris 06, LATMOS-IPSL; CNRS/INSU, LATMOS-IPSL, 75252 Paris Cedex 05, France
  3. European Commission, Joint Research Centre (JRC), I-21027 Ispra, Italy

Correspondence to: Lieven Clarisse1 e-mail: lclariss@ulb.ac.be




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