Investigating the terrestrial nitrogen cycling in a changing climate and its impact on N2O and NO emissions

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Investigating the terrestrial nitrogen cycling in
a changing climateand its impact on N2O and NO
emissions

• Vincent Prieur
• PhD director Michael Schulz
• Cooperation Soenke Zaehle, Benoit Gabrielle,
  Andrew Friend
• Laboratoire des Sciences du Climat et de
  l'Environnement (LSCE)
• vincent.prieur_at_lsce.ipsl.fr

3/04/2008
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Scientific questions

• Can we improve the N2ONO emission estimates by
  
• - including a N-cycle in ORCHIDEE
• - improving the representation of the soil
  processes
• (nitrification/denitrification)
• Is the nitrogen availability a limiting factor
  for long-term carbon sequestration in the future?
• What is the impact of an improved N2ONO
  emission inventory on the evolution of
  atmospheric chemistry and climate?

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Terrestrial Nitrogen Cycle
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The ORCHIDEE-CN model developed by Soenke Zaehle
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NOx - N2O emissions in ORCHIDEE
Important forcing

• Meteorology

• Precipitation

- Temperature

• Soil

• Texture

- pH

• Others

• Fertilizer

- Vegetation type
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pH sensitivity of the Denitrification
Decrease of the NO3 stock
Less NO3 available for plants
Increase of NOx and N2O emissions
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Data set

• Data source for model evaluation
• time-series of NO and N2O flux
• soil data ( texture, pH, fertilizer, )
• NOFRETETE data set
• 13 forest sites in Europe
• N-TWO-O (INRA Grignon)
• 4 crop sites in France ( Orléans )

Orléans
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Hoegwald , 2002 (Germany) (NOFRETETE data set)
ORCHIDEE vs Observations
2 soil layers
11 soil layers
Increasing the number of soil layers, with very
thin layers on the top, improve the prediction by
raising the response of the soil to rain and
evaporation.
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Future work

• Short term
• - Validation on multiples sites and possibly
  on other ecosytems ?
• - Demonstration of hydrology impact
• - Comparison with INRA model (CERES)
• Mid term upscaling to regional / global level,
  
• - requires a regional/global dataset
  (land-use, fertiliser amount,
• date of application)
• Final goal coupled simulations (LSM-GCM)
• ORCHIDEE - LMDZ-INCA - IPSL-ESM
  
• - How to construct forcing scenarios in
  ORCHIDEECN for the future ?
• - Comparison of carbon-climate and
  carbon-nitrogen-climate
• simulations

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THANK YOU
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