Modeling the surface–atmosphere exchange of ammonia

• Published in: Atmospheric environment (1994) Vol. 44; no. 7; pp. 945 - 957
• Main Authors: Kruit, R.J. Wichink, van Pul, W.A.J., Sauter, F.J., van den Broek, M., Nemitz, E., Sutton, M.A., Krol, M., Holtslag, A.A.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2010; Elsevier
• Subjects: agricultural grassland; Ammonia; apoplastic nh4; Applied sciences; Atmospheric pollution; Atmospheric transport model; Compensation point; Dry deposition; Exact sciences and technology; gradient measurements; intensively managed grassland; lolium-perenne; nh3 deposition processes; oilseed rape plants; Pollution; Resistance analogue; seminatural vegetation; Netherlands; Europe; Ammonia; Compensation point; Resistance analogue; Dry deposition; Atmospheric transport model; Grassland; Monocotyledones; Atmosphere model; Nitrogen compounds; Parameterization; Modeling; Transport process; Gramineae; Seasonal variation; Angiospermae; Lolium perenne; Atmospheric fallout; Pollutant behavior; Time scale; Plant leaf; Apoplast; Long term; Air pollution; Poison; Spermatophyta; Canopy(vegetation)
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2009.11.049

New parameterizations for surface–atmosphere exchange of ammonia are presented for application in atmospheric transport models and compared with parameterizations of the literature. The new parameterizations are based on a combination of the results of three years of ammonia flux measurements over a grassland canopy (dominated by Lolium perenne and Poa trivialis) near Wageningen, the Netherlands and existing parameterizations from literature. First, a model for the surface–atmosphere exchange of ammonia that includes the concentration at the external leaf surface is derived and validated. Second, a parameterization for the stomatal compensation point (expressed as Γ s , the ratio of [NH 4 +]/[H +] in the leaf apoplast) that accounts for the observed seasonal variation is derived from the measurements. The new, temperature-dependent Γ s describes the observed seasonal behavior very well. It is noted, however, that senescence of plants and field management practices will also influence the seasonal variation of Γ s on a shorter timescale. Finally, a relation that links Γ s to the atmospheric pollution level of the location through the ‘long-term’ NH 3 concentration in the air is proposed.