Changes between Version 3 and Version 4 of Tags/196/ExternalisationParameters

Timestamp:

2011-03-18T11:36:24+01:00 (13 years ago)

Author:

dsolyga

Comment:

--

Tags/196/ExternalisationParameters

@@ -2 +2 @@
 Page on Work of Didier Solyga on externalisation of parameters in ORCHIDEE.
 
+== Why a new version of ORCHIDEE ? ==
+
+In ORCHIDEE, the vegetation is currently represented by 13 Plants Functional Types or PFTs. 
+As these PFTs follow the same processes, they share the same set of parameters.
+(PS: that explained why the parameters in ORCHIDEE are under the shape of an array of 13 values.) [[BR]]
+
+The values of the parameters are different according to the PFTs. Moreover, many of these values
+are empirical and may differ according the papers.  What happens if you want to change a value
+of a parameters and want to see the changing involved by the modification? You have to find the
+parameter in the code, then change the value and to finish, you have to recompile ORCHIDEE.[[BR]]
+
+
+Moreover, 13 is a too restricted number for representing the PFTs. At the global scale, it is sufficient but at the
+regional scale, you are unable to represent the variability of the vegetation.[[BR]]
+
+The "externalisation" of the parameters of ORCHIDEE will allow us to solve these two problems.
+
+
+== Technical characteristics ==
+
+The externalized version of ORCHIDEE is build on the AR5 version of ORCHIDEE (tag 1.9.5, CVS version 1.11.22).
+
+
+With this version, the user has the possibility to choose a number of PFTs between 2 and X (X is any number, but
+a max value could be 94, corresponding to the Olson classification) and to change the values of less or more 300
+new parameters (plus the already externalized ones in the AR5).[[BR]]
+
+
+== The concept of Metaclass ==
+
+How did we solve the problems outlined in the section "What a new version of ORCHIDEE?" ? [[BR]]
+We use an formal concept called Metaclass(MTC in the following) based on an idea of N.Viovy.[[BR]]
+
+=== What is a Metaclass? ===
+
+It consists of an overlayer of the current PFTs. Here is the list of the MTCs implemented in the ORCHIDEE "externalizes" version : 
+
+
+
+
+=== How does it work? ===
+Basically, it will initialize all the pft-parameters by default values by linking a PFT to a MTC. 
+
+