Changes between Version 114 and Version 115 of DevelopmentActivities/ORCHIDEE-CNP


Ignore:
Timestamp:
2016-08-24T16:55:12+02:00 (8 years ago)
Author:
dgoll
Comment:

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  • DevelopmentActivities/ORCHIDEE-CNP

    v114 v115  
    2222 
    2323=== 3.2 soil mineral N dynamics === 
    24 Several modification of the original OCN (Zaehle & Friend, 2010) in ORCHIDEE-CN were kicked out and the original formulation are used again. See code for details. 
     24Several modification of the original OCN (Zaehle & Friend, 2010) in ORCHIDEE-CN I kicked out and instead use the original formulation are used again. See code for details. 
    2525Still, the mineral N stocks are unrealistic high. One approach to solve this is to use the modification to OCN described in the SI of Zaehle et al. (2011) ([http://://www.nature.com/ngeo/journal/v4/n9/extref/ngeo1207-s1.pdf]). 
    2626 
    2727The general problem with ORCHIDE-CN is that several details of soil mineral N were changed, which are all not tested. The easiest way would be to use the OCN formulation and parameters as OCN is well tested. 
    28  
    29 STATUS: 
    30 '''2016/08/07''': The disabling of NH4 fixation leads to somewhat lower mineral N levels, but they are still way to high. The amount of fixed NH4 looks reasonable to me and the coding is exactly like in OCN. 
    3128 
    3229'''2016/08/08''': I implemented the possibility to use the original OCN formulations for (1) nitrification, (2) denitrification, (3) rain drainage losses, and (4) anaerobic microsites.  In general, OCN uses simplified version of the ORCHIDEE-CN formulations to make sure that model runs stable on a global scale. When I suspect that OCN is buggy (frac_nh3), I keep the ORCHIDEE-CN formulation (I asked SZ to confirm the bugs).  
    … …  
    4138 
    4239'''2016/08/24''': The OCN nitrification compared to ORCHIDEE-CN (DNDC) uses a simplified temperature response function and a higher linear scaling factor (1.2 (not sure from where SZ took this value) compared to 0.2 (Schmidt et al. 2000)). As the NO3 levels are commonly much lower than NH4 in ORCHIDEE a higher baseline nitrification rate as in OCN makes sense. We thus take of the OCN formulation. 
     40 
     41'''Final mineral N dynamics:''' 
     42The mineral N dynamics in ORCHIDEE-CN-P are now exactly as described in Zaehle et al. (2011), except that I did not take over the rain drainage formulation as we use an improved hydrological scheme compared to Zaehle et al. (2011) which is able to simulate the rain drainage as a result of more soil layers (11 layers). 
     43 
     44The mineral N stocks of the test sites are all in realistic ranges. Tests on more sites are ongoing. 
    4345 
    4446