Changes between Version 108 and Version 109 of Documentation/TrunkFunctionality4

10/12/21 17:35:24 (8 months ago)



  • Documentation/TrunkFunctionality4

    v108 v109  
     316=== Mass balance closure === 
     317Mass balance closure is checked for carbon and nitrogen for all subroutines called from stomate and below. Depending on the setting of ERR_ACT the model will be stop runnin, a warning will be generated or the mismatch in the mass balance will only be written to the history files.If the model can be run without mass balance errors, we can be confident in the calculations but this does not imply that we can have the same confidence in the history files because some apparent and real mass balance problems may be introduced in between the calculation of a variable and the variable being written to the history files. Apparent problems come from : (1) temporal averaging by XIOS, (2) unit convertions (especially when the area of the pixel has to be taken into account). Apparent problems are detailed in ticket #798. Real problems can come from sending variables to the history files that are not included in the actual mass balance checks. 
    316320=== Mortality === 
    317321Describes r6614. ORCHIDEE trunk distinguishes 2 types of natural mortality: (1) explicitly considering mortality from disturbances and self-thinning, and (2) implicitly considering background mortality. Ideally, approach (1) should be further developed such that all underlying agents driving background mortality are represented in the model (i.e., gap-scale mortality, pests, disease, windthrow, etc.) such that it can replace approach (2). Two options of background mortality may be chosen: constant background mortality and dynamic background mortality. To use the first option, set the flag '''constant_mortality''' = y. The background mortality of a forests is calculated as a constant, prescribed fraction. In trunk, this fraction is given by '''residence_time''' (see also forest management). Otherwise set '''constant_mortality''' = n, the dynamic background mortality of a forest is a function of its net primary production (npp). If npp decreases, mortality will increase Both options have been developed but only '''constant_mortality''' = y has been tested in ORCHIDEE trunk.