Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation

Abstract

[1] We use 23 atmospheric chemistry transport models to calculate current and future (2030) deposition of reactive nitrogen (NO y , NH x ) and sulfate (SO x ) to land and ocean surfaces. The models are driven by three emission scenarios: (1) current air quality legislation (CLE); (2) an optimistic case of the maximum emissions reductions currently technologically feasible (MFR); and (3) the contrasting pessimistic IPCC SRES A2 scenario. An extensive evaluation of the present-day deposition using nearly all information on wet deposition available worldwide shows a good agreement with observations in Europe and North America, where 60-70% of the model-calculated wet deposition rates agree to within ±50% with quality-controlled measurements. Models systematically overestimate NH x deposition in South Asia, and underestimate NO y deposition in East Asia. We show that there are substantial differences among models for the removal mechanisms of NO y , NH x , and SO x , leading to ±1 s variance in total deposition fluxes of about 30% in the anthropogenic emissions regions, and up to a factor of 2 outside. In all cases the mean model constructed from the ensemble calculations is among the best when comparing to measurements. Currently, 36-51% of all NO y , NH x , and SO x is deposited over the ocean, and 50-80% of the fraction of deposition on land falls on natural (nonagricultural) vegetation. Currently, 11% of the world's natural vegetation receives nitrogen deposition in excess of the ''critical load'' threshold of 1000 mg(N) m À2 yr À1 . The regions most affected are the United States (20% of vegetation), western Europe (30%), eastern Europe (80%), South Asia (60%), East Asia

The composition, spatial patterns, and influencing factors of atmospheric wet nitrogen deposition in Chinese terrestrial ecosystems

“…Walaszek et al (2013) also proposed that the national N deposition budget was strongly correlated with precipitation, while the variability of annual precipitation did not change the general spatial patterns of wet deposition. Using models and stable isotope methods, many studies have demonstrated that anthropogenic emissions are the main source of atmospheric N deposition (Dentener et al, 2006;Jia and Chen, 2010;Zhang et al, 2012a). Galloway et al (2008) suggested that controlling reactive N emissions from fossil fuel combustion using maximum feasible reduction would result in a decrease of reactive N creation of 25 to 7 Tg N yr −1 , which could significantly decreased atmospheric N deposition.…”

Earth System Model Needs for Including the Interactive Representation of Nitrogen Deposition and Drought Effects on Forested Ecosystems

“…The current N deposition rate in some systems is over 10 kg ha −1 year −1 [4], which is well over the deposition rate from natural sources at 0.5 kg ha −1 year −1 [5]. Nitrogen deposits from industrial and agriculture activities have led to significant N loading in soils, particularly in regions of Europe and the eastern United States [6,7].…”

Ideas and perspectives: on the emission of amines from terrestrial vegetation in the context of new atmospheric particle formation

“…Even more pronounced is the increase of the production of organic residues from 25 Tg N yr −1 in 1850 to 125 Tg N yr −1 in 2000 (Holland et al, 2005). This increase is reflected by an increase of the N r deposition on the global scale, even in remote regions (Dentener et al, 2006;Galloway et al, 2008). Since the growth of plants is N-limited in many pristine ecosystems (Vitousek et al, 2002), it has to be assumed that the enhanced N-deposition has increased biomass turnover.…”