Changes between Version 7 and Version 8 of Users/ModelInterfacing/BiogeochemistryCoarsening

Timestamp:

2017-05-30T15:48:11+02:00 (7 years ago)

Author:

cbricaud

Comment:

--

Users/ModelInterfacing/BiogeochemistryCoarsening

@@ -4 +4 @@
 
 
+= Coarsening of physics for biogeochemistery model =
 
-
-= Coarsening of physics for biogeochemistery model =
+== Presentation ==
 
 A capacity of coarsening physics to force a BGC model coupled to NEMO has been developped in NEMO_3.6. This capacity allow to run 'online' a BGC model coupled to OPA-LIM with a lower resolution, to reduce the CPU coast of the BGC model, while preserving the effective resolution of the dynamics.
@@ -12 +12 @@
 
 This capacity is not included in the [https://forge.ipsl.jussieu.fr/nemo/browser/branches/2015/nemo_v3_6_STABLE/NEMOGCM NEMO_3.6] , but is available in a specific [https://forge.ipsl.jussieu.fr/nemo/browser/branches/2015/dev_r5003_MERCATOR6_CRS branch] of the 3.6 stable. This branch is regularly phazed with the NEMO_3.6.
+An associated ticket to follow evolution is  [https://forge.ipsl.jussieu.fr/nemo/ticket/1426 here].
+
+A presentation is available [xxx here], where the methodology is presented.
+
+
+== How to ? ==
+
+To activate the coarsening, key_crs should be added to list of cpp keys. This key will only activate the coarsening of dynamics.
+
+Some parameters are available in the namelist_cfg:
+
+
+{{{
+               !   passive tracer coarsened online simulations
+!-----------------------------------------------------------------------
+   nn_factx    = 3         !  Reduction factor of x-direction
+   nn_facty    = 3         !  Reduction factor of y-direction
+   nn_msh_crs  = 0         !  create (=1) a mesh file or not (=0)
+   nn_crs_kz   = 3         ! 0, volume-weighted MEAN of KZ
+                           ! 1, MAX of KZ
+                           ! 2, MIN of KZ
+                           ! 3, 10^(MEAN(LOG(KZ)) 
+                           ! 4, MEDIANE of KZ 
+   ln_crs_wn   = .false.   ! wn coarsened (T) or computed using horizontal divergence ( F )
+                           !                           !
+   ln_crs_top = .true.     !coarsening online for the bio
+/
+}}}
+
+- '''Only nn_factx = nn_facty = 3''' is available and the coarsening only works for grids with a T-pivot point for the north-fold lateral boundary condition( ORCA025, ORCA12,ORCA36,...).
+
+- '''nn_msh_crs  = 1''' : will activate the generation of the coarsened grid meshmask.
+
+- '''nn_crs_kz''' : is the operator to coarsene the vertical mixing coefficient. 
+
+- '''ln_crs_wn''' : when key_vvl is activated, this logical has no effect;  the coarsened vertical velocities are computed using horizontal divergence.
+              when key_vvl is not activated, coarsened vertical velocities are computed using horizontal divergence ( ln_crs_wn   = .false ) 
+                                             or coarsened vertical velocities are computed with an average operator ( ln_crs_wn   = .true. )
+- '''ln_crs_top = .true''': should be activated to run BCG model in coarsened space; so only works when key_top is in the cpp list and eventually key_pisces or key_my_trc.
+
+
+== Choice of operator to coarsene KZ == 
+
+A sensiblity test has been done with an Age tracer to compare the differents operagtor. 10^(MEAN(LOG(KZ)) or MEDIANE of KZ seems to provide the best resultats.
+
+Some results can be found [xxx here]
+