Assessing future nitrogen deposition and carbon cycle feedback using a multimodel approach: Analysis of nitrogen deposition

J.-F. Lamarque (1) , J.-T. Kiehl (1) , G.-P. Brasseur (2) , T. Butler (3) , P. Cameron-Smith (4) , W.-D. Collins (1) , W.-J. Collins (5) , Claire Granier (6, 2, 7) , Didier Hauglustaine (8, 9) , P.-G. Hess (1) , E.-A. Holland (1) , L. Horowitz (10) , M.-G. Lawrence (3) , D. Mckenna (1) , P. Merilees (1) , M.-J. Prather (11) , P.-J. Rasch (1) , D. Rotman (4) , D. Shindell (12) , P. Thornton (1)

1 NCAR - National Center for Atmospheric Research [Boulder]
2 MPI-M - Max Planck Institute for Meteorology
3 MPIC - Max Planck Institute for Chemistry
4 LLNL - Lawrence Livermore National Laboratory
5 MOHC - Met Office Hadley Centre
6 SA - Service d'aéronomie
7 CIRES - Cooperative Institute for Research in Environmental Sciences
8 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
9 MERMAID - Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics
10 GFDL - NOAA Geophysical Fluid Dynamics Laboratory
11 ESS - Department of Earth System Science [Irvine]
12 GISS - NASA Goddard Institute for Space Studies

In this study, we present the results of nitrogen deposition on land from a set of 29 simulations from six different tropospheric chemistry models pertaining to present-day and 2100 conditions. Nitrogen deposition refers here to the deposition (wet and dry) of all nitrogen-containing gas phase chemical species resulting from NOx (NO + NO2) emissions. We show that under the assumed IPCC SRES A2 scenario the global annual average nitrogen deposition over land is expected to increase by a factor of Å`2.5, mostly because of the increase in nitrogen emissions. This will significantly expand the areas with annual average deposition exceeding 1 gN/m2/year. Using the results from all models, we have documented the strong linear relationship between models on the fraction of the nitrogen emissions that is deposited, regardless of the emissions (present day or 2100). On average, approximately 70% of the emitted nitrogen is deposited over the landmasses. For present-day conditions the results from this study suggest that the deposition over land ranges between 25 and 40 Tg(N)/year. By 2100, under the A2 scenario, the deposition over the continents is expected to range between 60 and 100 Tg(N)/year. Over forests the deposition is expected to increase from 10 Tg(N)/year to 20 Tg(N)/year. In 2100 the nitrogen deposition changes from changes in the climate account for much less than the changes from increased nitrogen emissions.

Mots clés: nitrogen deposition; carbon cycle; nitrogen oxides; IPCC A2 scenario

Domaines: Océan, Atmosphère

J.-F. Lamarque, J.-T. Kiehl, G.-P. Brasseur, T. Butler, P. Cameron-Smith, et al.. Assessing future nitrogen deposition and carbon cycle feedback using a multimodel approach: Analysis of nitrogen deposition. Journal of Geophysical Research: Atmospheres, 2005, 110 (D19), pp.D19303. ⟨10.1029/2005JD005825⟩. ⟨hal-00077320⟩