Changes between Version 9 and Version 10 of Documentation/TrunkFunctionality4


Ignore:
Timestamp:
2020-03-09T13:49:00+01:00 (4 years ago)
Author:
luyssaert
Comment:

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  • Documentation/TrunkFunctionality4

    v9 v10  
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    91 === Albedo (snow) (CHECK) === 
    92 The snow albedo could be either prescribed (in condveg_init.f90) or calculated following Chalita and Treut (1994) '''do_new_snow_albedo = n ''' or calculated following CLM3 '''do_new_snow_albedo = y'''. The difference between the latter two methods has not been tested yet. The CLM method was added to CN-CAN, the Chalita and Treut method was added in parallel to the runk. When merging both versions we ended up with two options. 
     87=== Albedo (snow) (r6614) === 
     88The snow albedo could be either prescribed (the value of '''fixed_snow_albedo''' should then be set in the run.def and will be read in src_parameters/constantes_var.f90) or calculated following Chalita and Treut (1994) '''ok_snow_albedo_clm3 = n ''' or calculated following CLM3 '''ok_snow_albedo_clm3 = y''' (recommended). The difference between the latter two methods has not been tested yet. The CLM method was implemented in ORCHIDEE-CN-CAN and has been tested in combination with the other changes to the albedo calculations. The Chalita and Treut method was added in parallel to the ORCHIDEE trunk 3.0. When merging both versions, we ended up with two option. 
     89 
    9390 
    9491=== Allocation (r6614) === 
    95 ORCHIDEE-CN-CAN uses the allometric allocation as developed in O-CN. In ORCHIDEE-CAN the approach was adjusted to work for more than one diameter class. Since it was developed this allocation has been used in ORCHIDEE-CN and ORCHIDEE-CNP. In those branches only a single diameter class was used. Except for the way the reserves and labile pools are calculated (incl. the pseudo sugar loading), the allocation scheme remained rather similar between the aforementioned versions. The model is, however, very sensitive to the way the reserves and labile pools are calculated. The allocation makes use of a labile pool for which the activity is calculated based on the temperature. This sensitivity is important at the start and the end of the growing seasons when temperatures may be low. As such the model addresses the sink/source discussion initiated by Körner. Whereas this approach resulted in an acceptable interannual variability in for example NPP in ORCHIDEE-CAN, adding N seems to have dampen the interannual variability a lot/too much. This dampening was observed in ORCHIDEE-CN  and ORCHIDEE-CN-CAN. IN ORCHIDEE-CNP the temperature relationship was removed (hence NPP and GPP are strictly coupled) because the interannual variability became unrealistic.  
     92ORCHIDEE trunk 4 uses the allometric allocation as developed in O-CN. In ORCHIDEE trunk 4 the approach was adjusted to work for more than one diameter class. Since it was developed this allocation has been used in ORCHIDEE-CN and ORCHIDEE-CNP. In those branches only a single diameter class was used. Except for the way the reserves and labile pools are calculated (incl. the pseudo sugar loading), the allocation scheme remained rather similar between the aforementioned versions. The model is, however, very sensitive to the way the reserves and labile pools are calculated. The allocation makes use of a labile pool for which the activity is calculated based on the temperature. This sensitivity is important at the start and the end of the growing seasons when temperatures may be low. As such the model addresses the sink/source discussion initiated by Körner. Whereas this approach resulted in an acceptable interannual variability in for example NPP in ORCHIDEE-CAN, adding N seems to have dampen the interannual variability a lot/too much. This dampening was observed in ORCHIDEE-CN  and ORCHIDEE-CN-CAN. IN ORCHIDEE-CNP the temperature relationship was removed (hence NPP and GPP are strictly coupled) because the interannual variability became unrealistic.  
    9693 
    9794ORCHIDEE-CN-CAN calculates the number of individuals and uses this as a criterion to initiate a stand replacing disturbance. This approach, guided by the self-thinning relationship, avoids the need for a stand-level turnover time. ORCHIDEE-CN, and ORCHIDEE-CNP still make use of stand-level turnover.