Changes between Version 2 and Version 3 of GroupActivities/Meetings/Developer

2012-11-05T14:34:38+01:00 (12 years ago)



  • GroupActivities/Meetings/Developer

    v2 v3  
    4343 * Once the semi-analytic solution is merged in the trunk, forcesoil can be dumped and will no longer be maintained. The number of iterations required by the semi-analytic spin-up depends on the biomass. Hence, there is still room to use testomate. Given the possible instabilities of testomate, full ORCHIDEE could be used as an alternative. This will be further investigated. 
     47== DEV-Meeting May 10, 2012 == 
     49Place: LSCE 
     50PRESENT: around 20 people from ORCHIDEE-DEV mailing list 
     52The objective of the meeting was to present and discuss the results of the "ORCHIDEE - Hydrology 11 layers branch". 
     53This branch was created from the "AR5" main version, including all past developments on the new hydrology, including river routing, flood plains and some modifications due to soil freezing (LGGE work). The major contributions to the meeting were: 
     54(All presentations are accessible below) 
     561) '''Presentation of the 11 layer hydrology''' 
     58Although prepared by Agnes (not present), the presentation was given by Matthieu G., with the exposition of the concept of this new hydrology scheme. A little discussion/precision was made on the changes compared to the initial scheme developped by Patricia De-Rosnay. It concern mainly the number of water budget per grid point. Initially a water budget was made depending on the soil characteristics (3 budget for three major types of soil) while now there is 3 budget for the three main vegetation classes (trees, grasses, crop). 
     60Overall presentation prepared by Agnès Ducharne. See her [ Presentation]. 
     622) '''Results from Matthieu for the Amazon basin''' 
     64Matthieu compared several configurations (with/without STOMATE, different forcing files, and new hydro scheme versus old choisnel scheme) for the the Amazon basin. He looked at the river flow of the amazon and concluded that the current version with the new hydrology was leading to similar results than those obtained during previous work (with a different ORC version). 
     66Evaluation of the Hydro-Merge version over the Amazon River Basin by Matthieu Guimberteau. See his [ Presentation]. 
     683) '''Result on the SIRTA (Aurelien)''' 
     70(transparencies at the end of the general presentation of the new hydrology) 
     72Aurelien Campoy presented few slides on a comparison made at the SIRTA site (Saclay Plateau) on a force mode (SAFRAN), without STOMATE. He compared for bare soil the evaporation from the "branch" version with that from an older version with the new hydrology (IGPBAC) and concluded on no significant differences   
     744) '''Results on the Mediterranean basin (Jan Polcher)''' 
     76Jan compared simulations with new hydro between "the merge BRANCH" and his old working version, with WATCH forcing (without STOMATE). He obtained for July increased evapotranspiration with the merge branch, which seems to lead to a better agreement for the river discharge of major basins (Rhone). 
     78Evaluation of the Hydro-Merge version over the Mediterranean Basin by Jan Polcher. See his [ Presentation]. 
     804) '''Results at Fluxnet sites (Nicolas Vuichard)''' 
     82Nicolas presentation a first comparison at several fluxnet site of the evapotranspiration between the new scheme and the old one WITH STOMATE. It turns out that the new hydrology leads to large day to day variations in the evapotranspiration that are probably unrealistics. This points to the strong need of "recalibrating the water stress functions with the new scheme and STOMATE" 
     84Evaluation of the Hydro-Merge version on some Fluxnet sites by Nicolas Vuichard. See his [ Presentation]. 
     89== DEV-Meeting March 15, 2012 == 
     91Place: Jussieu 
     92PRESENT: around 20 people from ORCHIDEE-DEV mailing list 
     95 * Presentation by Juliane Otto of a "New Radiative Transfert scheme for ORCHIDEE" to compute the Albedo. See her [ Presentation]. An active discussion followed the presentation of Juliane and in particular several points were mentionned: 
     96   * Need to change the current handling of bare soil : "gather all PFT fractions not covered by leaves into PFT1 (bare soil)" with a new treatment : "consider separately the fraction covered or not by leaves for each PFT independantly". The Radiative transfert scheme will directly benefit from this improvement. 
     97   * The proposed RT scheme uses Monte Carlo simulations to compute the path of the photon within the canopy: This need to be change to reduce the computing time and to have "reproductive" results. 
     98   * The proposed RT scheme uses the output of "Forestry Management Module" to compute the geometry of the stand from from the tree diameters classes, height,... This need to be generalized so that the RT scheme works also with ORCHIDEE standard (without FM). Juliane plans to use some "standard geometry" following some work by B. Pinty. 
     99   * The proposed RT scheme uses three main parameters for the final albedo calculation (back ground albedo, single vegetation scattering albedo, preferential direction of scattering); these parameters are computed from MODIS satellite observations. Juliane presented values per PFTs for each month. This need to be generalized given that the seasonal variation are not the same btw North and South hemisphere for instance. 
     100   * Valentin B. raise the issue that the computation of an "Effective LAI" for the new RT scheme (compare to the "TRUE LAI") might change significantly the gross carbon production and that this need to be check carefully.   
     101   * The inclusion of the "snow" in this new RT scheme needs to be though more deeply. For that we propose to have soon a meeting with C. Ottle for a summary on the current developments of a new snow module for ORC and to discuss the coupling with the RT scheme. 
     102   * The treatment of Grasses still needs to be done. 
     104Note finally that Juliane is planning to first validate and publish the new RT scheme with FM module in a stand alone mode. 
     106 * General information about the ORCHIDEE project group 
     107  * Documentation effort (S. Luyssaert). [  Presentation] 
     108  * Merge 11-layer hydro version / 1952 (M. Guimberteau). [ Presentation] 
     109  * Other information (P. Peylin). [ Presentation]