Changes between Version 2 and Version 3 of 2016WP/Simplif2-CNRS-simona

Timestamp:

2016-03-09T18:47:18+01:00 (8 years ago)

Author:

acc

Comment:

--

2016WP/Simplif2-CNRS-simona

@@ -66 +66 @@
 }}}
 Once the PI has completed this section, he should send a mail to the previewer(s) asking them to preview the work within two weeks.
+
+------------------------------------------------------------------
+= Jointly Agreed Plan (in discussion with previewer) =
+The goal of this action is to continue Simplification started with ticket 1608, and
+https://forge.ipsl.jussieu.fr/nemo/wiki/ticket/1593_CNRS9_NOC3_LDF. For this action we
+will re-define interface between NEMO core and configurations and update all reference
+documentation to reflect the changes made.
+
+Configuration dependent code can be considered in four functional groups:
+
+1. Domain setting
+2. Initial state
+3. Forcing 
+4. Physics
+
+=== Phase 1: ===
+
+
+The first phase is to create a GYRE configuration which has no configuration dependent
+code in the standard modules.  This will be achieved by moving code in each of the
+functional groups (where appropriate) into 'user defined' modules which can be dropped
+into a MY_SRC directory and which are called by generic function names. Calls to these
+generic routines should be placed at appropriate points to be activated by suitable
+namelist switches. In the GYRE case this will involve relocating the following code
+segments:
+
+{{{
+(Domain) : CASE 5 for jphgr_msh in dom_hgr (two segments: grid and corolis);
+           single tanh function from zgr_z.
+(Initial): istate_gyre in istate.F90
+(Forcing): sbc_gyre in sbcana.F90
+(Physics): None
+}}}
+
+Remove specific calls to *_gyre routines and verify results using the 'user defined'
+routines
+
+=== Phase 2: ===
+
+The second phase of this task is to introduce a method of reading all domain settings from
+external files. Currently this is done for horizontal grid information if jphgr_msh=0 but
+there is no similar mechanism for the vertical grid. For a complete domain description
+(ignoring the possibility of iceshelves, for now) the following data are required:
+
+
+{{{
+gphi[t,u,v,f], glam[t,u,v,f], e[1,2][t,u,v,f] ( and optionally e1e2[u,v] ) 
+gdep[t,w]_0 gdep[t,w]_1d
+e3[t,w,u,v,f]_0 e3[t,w,u,v,f]_1d
+tmask
+jperio, ln_zps, ln_zco, ln_sco, ln_isfcav
+}}}
+
+
+Note [u,v,f]masks can be derived from tmask. A configuration-dependent fmask, in
+particular, should be considered as a physics choice since it can be used to increase
+lateral friction.
+
+The phase 2 task is therefore to introduce code to produce a mesh and mask file with all
+the required content (by changing/adding to nn_msh options). A new namelist parameter can
+then be added (jpzgr_msh) such that when jpzgr_msh = 0,  a new routine, zgr_read, called
+in domzgr will read the vertical grid information from the mesh and mask file: 
+
+{{{
+SELECT CASE( jpzgr_msh )   !  type of vertical grid  
+!
+CASE ( 0 )                     !==  read in domain.nc file  ==!
+   !
+   IF(lwp) WRITE(numout,*)
+   IF(lwp) WRITE(numout,*) '          vertical grid read in "domain" file'
+   !
+   CALL zgr_read()
+   ! add code to build mbathy from tmask: needed in zgr_bot_level 
+   ! possibly build bathy too from gdepw_0 ; after zgr_bot_level? is it needed?
+   !
+CASE DEFAULT
+   !
+   ! Build the vertical coordinate system
+   ! ------------------------------------
+   CALL zgr_z            ! Reference z-coordinate system (always called)
+   CALL zgr_bat          ! Bathymetry fields (levels and meters)
+   IF( lk_c1d      )   CALL lbc_lnk( bathy , 'T', 1._wp )   ! 1D config.: same bathy value over the 3x3 domain
+   IF( ln_zco      )   CALL zgr_zco          ! z-coordinate
+   IF( ln_zps      )   CALL zgr_zps          ! Partial step z-coordinate
+   IF( ln_sco      )   CALL zgr_sco          ! s-coordinate or hybrid z-s coordinate
+   !
+   ! final adjustment of mbathy & check 
+   ! -----------------------------------
+   IF( .NOT.lk_c1d )   CALL zgr_bat_ctl      ! check bathymetry (mbathy) and suppress isolated ocean points
+END SELECT
+   IF( lzoom       )   CALL zgr_bat_zoom     ! correct mbathy in case of zoom sub
+                       CALL zgr_bot_level    ! deepest ocean level for t-, u- and v-points
+                       CALL zgr_top_level    ! shallowest ocean level for T-, U-, V- points
+}}}
+
+Note: The same domain file read in zgr_read is also to be accessed in hgr_read for the
+horizontal grid information (jphgr_msh=0).
+
+The ability to reproduce results from all reference configurations using the external
+files to define the domain should be verified at this stage.
+
+=== Phase 3: ===
+
+
+The third phase will be to identify configuration dependent physics code and replicate the
+functions (or case statement blocks) either by providing user defined functions or reading
+appropriate fields from external files. The afore-mentioned fmask modifications are one
+example which could be replaced by reading a modified fmask from an external file.
+
+After this phase it should be possible to run an ORCA2 configuration with no hardcoded
+references in the trunk code.
+
+=== Phase 4: ===
+
+Following success with phases 1-3 the next stage will be to systematically break down the
+multiple functionality in routines such as domhgr into separate examples of user-defined
+routines (in this case a set of routines, each of which sets a different vertical grid).
+Care should be taken to standardise subroutine arguments with inputs and return fields
+clearly documented. These new routines should be moved into the appropriate MY_SRC
+directory of a reference configuration or into a new directory under TOOLS or
+MISCELLANEOUS if they are not actively used in any of the reference configurations.
+domhgr.F90 and domzgr.F90, in particular, should be greatly simplified by this procedure.
+
+=== Phase 5 ===
+ 
+Incorporate necessary additions to the domain.nc file to support ISF active configurations
+(misfdep, risfdep?) and check for possible redundancy in domain.nc (i.e. are all the
+fields really required?). Not sure _1d arrays are, for example?
+
+Finally check that documentation has been kept up to date.
 
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