Changes between Version 4 and Version 5 of Documentation/CouplingLMDZ


Ignore:
Timestamp:
2014-10-28T10:54:49+01:00 (10 years ago)
Author:
peylin
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • Documentation/CouplingLMDZ

    v4 v5  
    55The main points concern i) the treatment of the Evaporation and how the "beta" factor (soil water stress) is treated as well as how the potential evaporation is calculated and ii) the treatment of the radiation in ORC (longwave and shortwave) to ensure energy conservation when coupled with LMDz. 
    66 
    7 Several document have been produced and are usefull to understand such coupling and the major points: 
     7Several documents have been produced and are usefull to understand such coupling and the major points: 
    88 
    9  - Updated-note on the coupling by Polcher: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/Polcher_coupling_newformulation.pdf" "Note"] 
     9 - General Coupling with GCM: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/Polcher_coupling_newformulation.pdf" "Article on Coupling"] 
     10 - Updated-note on the coupling by Polcher: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/Polcher_coupling_newformulation.pdf" "Updated note (Polcher)"] 
     11 - Note by Dufresne and Ghattas on coupling with LMDZ: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/Dufresne, Ghattas - 2009_Coupling-ORC-LMDZ.pdf" "Dufresne & Ghattas"] 
     12 - New note by Fuxing on recent implementations: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/Fuxing_orchidee_lmdz_coupling_20140428.pdf" "Fuxing note"] 
    1013 
    1114 
    … …  
    1316 
    1417 
    15 1-a. evaporation during coupling (beta problem).  
     18== Evaporation during coupling (beta problem) ==  
    1619 
    1720(a). In the trunk of ORCHIDEE, the stress factor beta is missing in the denominator in the sensitivity of the latent heat flux to the surface temperature at the old time step. This is coded in enerbil: 
    … …  
    2124larsub_old = chalsu0 * vbeta1 * (un - vbeta5) * (peqBcoef -  qsol_sat) / (zikq - vbeta1 * (un - vbeta5)* peqAcoef) 
    2225 
    23 1-b. However the implementation of the potential evaporation formula (established for a moist surface {ETP=rau/ra*[qs(T*)-qa]} ) is not satisfactory; it considers qstat(Ts) and not qsat(T*), temperature of a moist surface and thus over-estimates the evaporation. In the present version, this is tackled by correcting the bare soil evaporation afterwards with the Milly approach. 
     26== Overestimation of Potential Evaporation == 
     27 
     28However the implementation of the potential evaporation formula (established for a moist surface {ETP=rau/ra*[qs(T*)-qa]} ) is not satisfactory; it considers qstat(Ts) and not qsat(T*), temperature of a moist surface and thus over-estimates the evaporation. In the present version, this is tackled by correcting the bare soil evaporation afterwards with the Milly approach. 
    2429 
    2530Jan proposed improved approaches based on the Penman-Monteith method for ETP. They have been developed by Anais Barella during her PhD thesis and tested in forced mode. The correct surface energy budget equation for the implicit coupling is not yet available and work has to be done before implementing this approach in Orchidee.trunk.  http://www.lmd.polytechnique.fr/~intro/Files/2014_These_Barella.pdf).