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Towards a climate-dependent paradigm of ammonia emission and deposition
Citation:
Sutton, M., S. Reis, S. Riddick, U. Dragosits, E. Nemitz, M. Theobald, Y. Tang, C. Braban, M. Vieno, A. Dore, R. Mitdhell, S. Wanless, F. Daunt, D. Fowler, T. Blackall, C. Milford, C. Flechard, B. Loubet, R. Massad, P. Cellier, E. Personne, P. Coheur, L. Clarisse, M. van Damme, Y. Ngadi, C. Clebaux, C. Skjoth, C. Geels, O. Hertel, R. Wickink Kruit, R. Pinder, J. Bash, Johnt Walker, D. Simpson, L. Horvath, T. Misselbrook, A. Bleeker, F. Dentener, AND W. de Vries. Towards a climate-dependent paradigm of ammonia emission and deposition. PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON. Royal Society, London, Uk, 368(1621):01666, (2013).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL′s)Atmospheric Modeling Division (AMAD) conducts research in support of EPA′s mission to protect human health and the environment. AMAD′s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation′s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Existing descriptions of bi-directional ammonia (NH3) land–atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate-dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission–deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary foundation to assess the consequences of climate change. Based on available measurements, a first empirical estimate suggests that 5°C warming would increase emissions by 42 per cent (28–67%). Together with increased anthropogenic activity, global NH3 emissions may increase from 65 (45–85) Tg N in 2008 to reach 132 (89–179) Tg by 2100.
