Changes between Version 175 and Version 176 of DevelopmentActivities/ORCHIDEE-DOFOCO


Ignore:
Timestamp:
2018-11-29T09:48:13+01:00 (5 years ago)
Author:
mmcgrath
Comment:

A few questions, comments, discussion points to consider.

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  • DevelopmentActivities/ORCHIDEE-DOFOCO

    v175 v176  
    396396The work will likely require several iteration containing all or just a coupled of the following: 1) running the model, 2) tuning key parameters, 3) re-running the model 4) spin-up and 5) evaluating to model, to discern parameter values that allow us to reproduce as closely as possible the global patterns and trends for several key processes. The tests will move across scales starting at pixel scale moving to longitudinal band, European scale and ending at global scale. Although the longitudinal bands are of little use in the evaluation itself they can be considered pre-tests before global tests are run. It is hoped that longitudinal bands would speed up the tests and reduce the computational cost. 
    397397 
     398''CLARIFICATION: Is the reduction of computational cost due to the longitudinal tests finding bugs that would otherwise only appear in global runs?'' 
     399 
    398400Table 1. Workflow of the parameterization and evaluation of ORCHIDEE-CN-CAN. 
    399401|| '''Phase''' || '''Work to be done''' ||  
    … …  
    406408=== Apparent bug-free === 
    407409Before starting the work proposed in Table 1 it needs to be confirmed that the model is technically capable of the tasks presented in Table 2. 
     410 
     411''QUESTION: Are we aiming for 500-1000 years with full debug flags on both obelix and irene to increase our confidence?  That might be too expensive even at 2 degree resolution for a global run, but we could check.'' 
    408412 
    409413Table 2. Essential technical capabilities before evaluating ORCHIDEE-CN-CAN. 
    … …  
    480484* Forest management = 2 (i.e., accounting for a thin and fell type of forest management) 
    481485 
     486''QUESTION: Do we consider litter raking on site level?  Do we consider litter raking for FLUXNET evaluations?'' 
     487 
    482488European simulations will have the following configuration: 
    483489* Start from a spin-up 
    … …  
    516522Only if we experience too many difficulties with manual tuning (if there are too many non-linearities in the model), we will use the multi-site optimization tool developed by Vlad . When the simulated growth dynamics are satisfying, 140 years long tests will be performed to check cumulative variables such as basal area, tree height, tree diameter, stand density, standing biomass, and harvest. To evaluate net ecosystem exchange of carbon and soil carbon and nitrogen pools a spin-up is required. Note that the spin-up depends on the parameters used in ORCHIDEE and that the sensitivity of parameters in ORCHIDEE depends on the spin-up. There is no easy way to break this dependency. We should avoid to ‘over-tune’ the 1-pixel FLUXNET comparisons. Instead, we will continue evaluating the model over longitudinal bands.  
    517523 
     524''DISCUSSION POINT: The current scripts for FLUXNET evaluation are broken down into three parts.  1) An initial looping over the driver file (1-10 years, depending on the file), 2) 500 years of spinup (regardless of the length of driver file), 3) one final loop over the driver file, for production.  I like how the process is described above, and agree that makes a lot of sense for forests.  In particular, I think we need 80 years from planting after spinup plus a production run over the forcing file to avoid trees dying and biasing our results.  It's not clear how much time it will take to coax the scripts to do this.  I think the grassland and cropland sites can easily use the existing setup.  We also may have an issue with age classes, as that changes the PFT of interest (but should be straightforward to fix).'' 
     525 
    518526 
    519527==== Settings for longitudinal bands ==== 
    … …  
    542550•       A dynamic N-cycle (impose_cn=n) 
    543551•       N-deposition, we have N-deposition files from approximately 1860 until present. 
     552 
     553''DISCUSSION POINT: We are not guaranteed that the European control will be able to be used as a restart for other runs.  For example, we expect VERIFY to be at 11 km resolution suing completely different forcing data. Does this change at all how we want to proceed?  Or is that a separate issue?  I think it makes sense to do the evaluation as stated, and then do what is needed for the other runs separately.'' 
    544554 
    545555Table 5. Observational data products to evaluate European control simulation