Changes between Version 54 and Version 55 of Documentation/TrunkFunctionality4


Ignore:
Timestamp:
2020-06-29T15:06:15+02:00 (4 years ago)
Author:
luyssaert
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • Documentation/TrunkFunctionality4

    v54 v55  
    305305The following PFT dependent parameters are needed for the calculations accounting for plant hydraulic architecture; minimal leaf water potential '''psi_leaf''', sapwood leaf water potential that causes 50 % loss of xylem '''psi_50''', maximum sapwood conductivity '''k_sap''', root conductivity '''k_root''', leaf conductivity '''k_leaf''', specific root lenght '''srl''', fine root radius '''r_froot''', minimum root water potential '''psi_root'''. Moreover, as a further refinement to the hydraulic architecture, a more detailed description of the soil to root resistance has been included. This overcomes the need of psi_soil_tune in ORCHIDEE trunk as needed in ORCIDEE-CAN. Psi_soil is weighted by the fraction of evapotranspiration supplied by each soil layer, which depends on  the soil to root resistance per layer that accounts for different root properties and hydraulic conductivity. In ORCHIDEE-CAN '''k_root''' described the conductivity of the fine roots and the soil. In ORCHIDEE trunk this joined conductivity has been split in a fine root conductivity and a soil to root conductivity. '''k_root''' is solely used in the calculation of the hydraulic architecture (because k soil to root is calculated separately in that subroutine), '''k_belowground''' is solely used in allocation. Hence, allocation and hydraulic architecture are no longer intimately linked.  
    306306 
     307The soil hydrology model distinguishes three water columns, the so called soil tiles. The first soil tile simulates the water contained under PFT1, the second the soil water contained under forest PFTs and the third the water contained under short vegetation PFTs (grasses and crops). PFTs are linked to soil tiles by means of the parameter '''pref_soil_veg''' (in src_parameters/constantes_mtc.f90). Note that both transpiration (veget) and evaporation (frac_bare_ns) is taken from the same soil tile. 
    307308 
    308309=== Prescribe initial vegetation ===