Development and evaluation of an ammonia bidirectional flux parameterization for air quality models
Article first published online: 8 MAY 2013
©2013. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Atmospheres
Volume 118, Issue 9, pages 3794–3806, 16 May 2013
How to Cite
2013), Development and evaluation of an ammonia bidirectional flux parameterization for air quality models, J. Geophys. Res. Atmos., 118, 3794–3806, doi:10.1002/jgrd.50262., , , and (
- Issue published online: 31 MAY 2013
- Article first published online: 8 MAY 2013
- Accepted manuscript online: 4 MAR 2013 04:16PM EST
- Manuscript Accepted: 8 FEB 2013
- Manuscript Revised: 16 DEC 2012
- Manuscript Received: 7 SEP 2012
- air quality model;
- bi-directional flux
 Ammonia is an important contributor to particulate matter in the atmosphere and can significantly impact terrestrial and aquatic ecosystems. Surface exchange between the atmosphere and biosphere is a key part of the ammonia cycle. New modeling techniques are being developed for use in air quality models that replace current ammonia emissions from fertilized crops and ammonia dry deposition with a bidirectional surface flux model including linkage to a detailed biogeochemical and farm management model. Recent field studies involving surface flux measurements over crops that predominate in North America have been crucial for extending earlier bidirectional flux models toward more realistic treatment of NH3 fluxes for croplands. Comparisons of the ammonia bidirection flux algorithm to both lightly fertilized soybeans and heavily fertilized corn demonstrate that the model can capture the magnitude and dynamics of observed ammonia fluxes, both net deposition and evasion, over a range of conditions with overall biases on the order of the uncertainty of the measurements. However, successful application to the field experiment in heavily fertilized corn required substantial modification of the model to include new parameterizations for in-soil diffusion resistance, ground quasi-laminar boundary layer resistance, and revised cuticular resistance that is dependent on in-canopy NH3 concentration and RH at the leaf surface. This new bidirectional flux algorithm has been incorporated in an air quality modeling system, which also includes an implementation of a soil nitrification model.