Lateral transfer of C / N / P compounds

In the context of the ESM2025 project we started a new "task force" on the merge of existing developments around the lateral transfert of C / N / P compounds in ORCHIDEE with the objective to have all developments in a unique version (the Trunk) to allow ESM simulations (with the coupling between land - ocean - atmosphere)

• Persons involved: Pierre Regnier (UCL), Goulvain Laruelle (UCL), Haicheng Zhang (UCL), Nicolas Vuichard (LSCE), Philippe Ciais (LSCE), Philippe Peylin (LSCE), Rony Lauerwald (Inrae), Bertrand Guenet (ENS),
• Coordination (in charge of organising regular meeting on this topic): Pierre R. and Nicolas V.

First meeting 13 December 2021

Present: Pierre Regnier (UCL), Goulvain Laruelle (UCL), Haicheng Zhang (UCL), Nicolas Vuichard (LSCE), Philippe Ciais (LSCE), Philippe Peylin (LSCE), Rony Lauerwald (Inrae), Bertrand Guenet (ENS)

We mainly discussed what are the existing developments linked to lateral transfers of C / N / P compounds (organic and inorganic): Several branches / versions exists:

• ORC-PEAT: a peatland model version that is provides crucial input for the transfert of compounds in the arctic
• ORC-CN-Vertical (reference as ORC-V3, a tag of the TRUNK): Content the N cycle and the vertical discretisation of C in the soil (following that of MICT); this version is currently coupled to the ESM
• ORC-Vertical-SOC/DOC/POC/Priming/: used by Rony ???
• ORC-DIC/mangrove : developped by Simon Bowring and currently re-used for a Mangrove project by Bertrand
• ORC-Peat-MICT-SOC/DOC/DIC : developed by Chunjing and tested over a few sites

=> Several versions exists and given the need to have a "lateral transfer module" that can work with different ORCHIDEE version for different objectives the proposed strategy is :

• Develop a "transport routine" as independant as possible of the production in the sols of different compounds
• Need to see if the transport module can be "de-coupled" from the "water routing.f90 routine" ?
• Start the coupling with ORCHIDEE-CN (V3) so that it can first meet the needs of ESM2025
• Have soon a meeting with the groups developping the water routing scheme and the energy transfer (Temperature calculation)

=> First technical meeting will take place on the 16 December in Paris with Nicolas, Pierre, Haicheng => Pierre will organise the next teleconf. => We need to add few other people in the discussion (Daniel G., Chunjing, Elodie, ...)