Changes between Version 100 and Version 101 of Documentation/TrunkFunctionality4


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Timestamp:
05/06/21 13:41:36 (3 months ago)
Author:
luyssaert
Comment:

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  • Documentation/TrunkFunctionality4

    v100 v101  
    504504 
    505505=== Spin-up === 
    506 Describes r6614. The analytical spin-up works with ORCHIDEE trunk. To ensure growth at the onset of the analytic spin-up for all PFTs initial values are needed for the SOM pools, and that is  irrespective of whether IMPOSE_CN is y or n. The initial pools are set in stomate_io.f90, and they can be specified in the run.def by: 
     506Describes r7178. The analytical spin-up works with ORCHIDEE trunk. To ensure growth at the onset of the analytic spin-up for all PFTs initial values are needed for the SOM pools, and that is  irrespective of whether IMPOSE_CN is y or n. The initial pools are set in stomate_io.f90, and they can be specified in the run.def by: 
    507507{{{ 
    508508SOM_INIT_ACTIVE = 1000 
     
    512512}}}  
    513513The initial values of carbon for the four SOM pools are used globally. Sensitivity test have shown that the analytic spin-up is not sensitive to the actual size of the initial values. The different ecosystems will after a while settle into their own states (N limited or saturated) in spite of having the same initial state. Convergence appears to be faster if initial values are set. 
     514 
     515Whether the analytical spinup will be used or not is set in COMP/stomate.card by the parameter SPINUP_ANALYTIC. By default the SPINUP_PERIOD is calculated as the length of the time series used in cyclic_begin and cyclic_end as set in the config.card. This calculation is done in the COMP/stomate.driver 
     516{{{ 
     517### Begin Code in COMP/stomate.driver                                            
     518    if [ X${stomate_UserChoices_SPINUP_ANALYTIC} = Xy ] ; then                   
     519       IGCM_comp_modifyDefFile nonblocker orchidee.def SPINUP_ANALYTIC y         
     520                                                                                 
     521       # Test if CyclicBegin and CyclicEnd is set in config.card                 
     522       if ( [ X${config_UserChoices_CyclicBegin} = X ] || [ X${config_UserChoices_CyclicEnd} = X ] ) ; then 
     523           IGCM_debug_Exit "CyclicBegin and CyclicEnd must be set in config.card to run option spinup_analytic." 
     524       fi                                                                        
     525       # Calculate and set number of years of forcing data                       
     526       CycleNb=$(( ${config_UserChoices_CyclicEnd} - ${config_UserChoices_CyclicBegin} + 1 )) 
     527       IGCM_comp_modifyDefFile nonblocker orchidee.def SPINUP_PERIOD ${CycleNb} 
     528    else                                                                         
     529        IGCM_comp_modifyDefFile nonblocker orchidee.def SPINUP_ANALYTIC n        
     530        IGCM_comp_modifyDefFile nonblocker orchidee.def SPINUP_PERIOD -1         
     531    fi                                                                                                                                        
     532### End Code in COMP/stomate.driver   
     533}}} 
     534 
     535The calculated value can be overwritten by setting SPINUP_PERIOD in PARAM/orchidee.def. 
     536  
     537In rXXXX a pre-spinup was introduced as SPINUP_ANALYTIC_FG0 and SPINUP_ANALYTIC_FG0nd. The purpose of the pre-spinup is to break the synchronicity of neighboring pixels. With FG0, all pixels will be zero years old at t=0 of the FG1 spinup. Because neighboring pixels often experience the same climate and have the same soil properties they will all mature and die within the same decade. This results in some cyclic NBP for some PFTs. FG0 is run for 200 years and within this 200 years each pixel x PFT is cut once at random (the random cutting is prescribed through a map and is therefore reproducible). This random cutting breaks the synchronicity of neighboring pixels and is thought to result quicker in a more stable steady-state (to be confimed).  
    514538 
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