Changes between Version 104 and Version 105 of DevelopmentActivities/ORCHIDEE-CNP

Timestamp:

2016-06-28T17:04:17+02:00 (8 years ago)

Author:

dgoll

Comment:

--

DevelopmentActivities/ORCHIDEE-CNP

@@ -21 +21 @@
 Following Smith et al (2014), I introduced the use of the maximum water holding capacity of soils (max_var_eau) to approximate pore space which to derive the average soil mineral N concentration in solution. The use of the actual water volume can not be recommended as we this would lead to high N concentration in soil water when soil water is very low. As we do not account for the inhibition of replenishment of mineral N in the soil solution around roots when soil water is scarce. 
 
-=== 3.2 Biological N2 fixation (BNF) ===
-=== 3.2.1 Modified Cleveland et al. (1999) scheme ===
+=== 3.2 soil mineral N dyanmics ===
+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.
+Still, 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]).
+The general problem is that several details were changed in the soil mineral N routine, which are not tested. And more modification are needed.
+The easiest way would be to use the OCN formulation and parameters. They are well tested, while the ORCHIDEE-CN modification are not tested.
+
+=== 3.3 Biological N2 fixation (BNF) ===
+=== 3.3.1 Modified Cleveland et al. (1999) scheme ===
 We introduce a module which computes BNF as a function of NPP, tissue C:N, and tissue & N:P. This approach is based on Cleveland et al (1999), Thornton et al. (2007), and Goll et al. (2012).
 When using the analytical spinup the BNF must be read in from a file to speed up the spin up. The file should contain the reference BNF rates for the respective climatic conditions.
 Such files are currently missing, but should be generated as soon as the model is ready.
-=== 3.2.2 Biological N2 fixation (BNF) from  Yingping ===
+=== 3.3.2 Biological N2 fixation (BNF) from  Yingping ===
 The Cleveland scheme is heavily criticized due to good reason. Yingping Wang will provide maps with annual rates of BNF computed based more or less on Wang et al. (2007) for the historical period. To do so, Yingping needs TRENDY style simulations with a calibrated model.After publication of his model, he will share the code with us & we can compute BNF dynamically in ORCHIDEE.