| 12 | |
| 13 | == Model configurations and associated forcings == |
| 14 | The standard configuration of ORCHIDEE_3 accounts for a dynamic nitrogen cycle in which Nitrogen content in soil and plant reservoirs varies accordingly to environmental conditions. In this configuration, compared to Carbon-only model versions like ORCHIDEE_2, additional forcings are needed related to different nitrogen inputs: |
| 15 | * Nitrogen atmospheric deposition: ORCHIDEE_3 considers seperately reduced (NHx) and oxydised (NOy) forms of nitrogen. By default, one uses the monthly atmospheric N deposition during 1860 - 2014 from the IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) as in the Tian et al. (2019) and the current GCB papers. They are stored on the shared repositories here: |
| 16 | * ${R_IN}/SRF/NITROGEN/N_DEPOSITION/CCMI_ndep/historical/CCMI_ndep_nhx_${year}.nc |
| 17 | * ${R_IN}/SRF/NITROGEN/N_DEPOSITION/CCMI_ndep/historical/CCMI_ndep_noy_${year}.nc |
| 18 | * Synthetic fertilizer use: By default, one uses annual data from Lu and Tian, 2017 (https://doi.pangaea.de/10.1594/PANGAEA.863323) which provide the annual synthetic/mineral N fertilizer rate from 1960 to 2014 specifically for croplands and grasslands. They are stored on the shared repositories here: |
| 19 | * ${R_IN}/SRF/NITROGEN/N_FERTILISATION/NMIP/synthetic/historical/Nfer_pasture_${year}.nc |
| 20 | * ${R_IN}/SRF/NITROGEN/N_FERTILISATION/NMIP/synthetic/historical/Nfer_cropland_${year}.nc |
| 21 | * Organic fertilizer use: By default, one uses gridded annual manure N production in the period of 1860-2014 developed by Zhang et al., 2017 (https://doi.org/10.1594/PANGAEA.871980) and applied separately on grasslands and croplands. They are stored on the shared repositories here: |
| 22 | * ${R_IN}/SRF/NITROGEN/N_FERTILISATION/NMIP/manure/historical/Nmanure_pasture_${year}.nc |
| 23 | * ${R_IN}/SRF/NITROGEN/N_FERTILISATION/NMIP/manure/historical/Nmanure_cropland_${year}.nc |
| 24 | The use of manure in the model has to be done with caution as it added carbon in the ecosystem as well. This carbon is taken for the crop harvested biomass which is deduced from this term |
| 25 | * Biological nitrogen fixation: In ORCHIDEE-3, there is no computation of the BNF rate. One uses a single climatology for BNF as a function of present-day evapotranspiration following the approach of Cleveland et al. (1999). The forcing used by default is stored on the shared repositories here: ${R_IN}/SRF/NITROGEN/BNF/bnf_1850.nc |