Changes between Version 1 and Version 2 of 2014WP/2014_SystemSimplification_v2

Timestamp:

2014-02-05T13:59:44+01:00 (10 years ago)

Author:

gm

Comment:

--

2014WP/2014_SystemSimplification_v2

@@ -1 @@
-'''Note on possible system simplification'''
+'''Note on system simplification'''
+[[BR]]
+[[BR]]
 
 '''Motivation''':
 
 We need to simplify the code for maintenance, robustness and future evolution (change in time stepping, …etc). This means fewer options, and a consensus on the default (and thus well validated) set of numerics.
+The idea is to change the current most used choices from : [[BR]]
+   linear filtered free surface zps ocean with TVD, "Madec" iso-neutral diffusion, and standard equation of state ;  levitating sea-ice with virtual salt fluxes
 
-The idea is to change the current most used choices from : 
-
-linear filtered free surface zps ocean with TVD, "Madec" isoneutral diffusion, and standard equation of state ;  levitating sea-ice with virtual salt fluxes
-
-possibly to :
-
-Non linear (vvl), split-explicit (ts) free surface, mixte zps/s-coordinate ocean with 3rd order advection (UBS),  "Griffies" isoneutral diffusion ; embedded multi-category sea-ice (exact fluxes).
-
+possibly to :[[BR]]
+   Non linear (vvl), split-explicit (ts) free surface, mixte zps/s-coordinate ocean with 3rd order advection (UBS with rotation of the diffusive part along iso-neutral surfaces),  "Griffies" iso-neutral diffusion ; embedded multi-category sea-ice (exact fluxes).
 And this with a removing of obsolescent features and a cleaning of the code.
 
-Timing: ideally, no more than 2 years from now (to be ready for CMIP6, and on time for the foreseen evolution of the time stepping)
+Timing: achievement within 2 years from now for NEMO v4.0 (to be ready for CMIP6, and on time for the foreseen evolution of the time stepping)
 
-'''* core action (supported by all system team)'''
+Notations: 
 
-'''- desired, but subject to discussion '''
+   '''*'''  core action (supported by all system team)
 
-'''? feasible but all conditions required are not yet met  '''
+   '''-'''  desired, but subject to discussion
 
-'''CHANGE in paradigm'''
+   '''?'''  feasible but all conditions required are not yet met
+[[BR]]
+[[BR]]
+'''CHANGE in options used by default'''
 
-'''*''' • default : non-linear free surface ('''planned''' '''in 2014''')
+'''*''' '''non-linear free surface''': by default ('''WP 2014''')
 
-'''*''' • remove filtered free surface and all associated solvers (if yes when? 2014?)
+'''*'''  '''filtered free surface''': remove it as well as all its associated solvers (if yes when? 2014?)[[BR]]
+                 (required AGRIF with time-splitting, '''done''' in 2013) and deeply tested ('''WP 2014''')
 
-                (required AGRIF with time-splitting, '''done''' in 2013) and deeply tested ('''planned''' 2014)
+'''*'''  '''vertical coordinate''' : default option mixte zps/s-tilde coordinate (thus with variable volume level), with mixte zps*/s*, mixte z/s, zps, z and s coordinate system as sub-option (same code used) (2014-2015 ?)
 
-'''*''' • vertical coordinate : default option mixte zps/s-tilde coordinate (thus with variable volume level), with mixte zps*/s*, mixte z/s, zps, z and s coordinate system as sub-option (same code used) (2014-2015 ?)
+                !-  tracer solved as thickness weighted tracer: D,,t,,(e,,3t,, T) ('''WP 2014''')
 
-                - tracer solved as thickness weighted tracer: D,,t,,(e,,3t,, T) ('''planned''' '''2014''')
+                !-  thickness weighted quantities in the outputs ('''WP2014''')
 
-                - thickness weighted quantities in the outputs ('''planned''' '''2014''')
+                !-  no more substitute (domzgr_substitute.h90): all e3 always defined at before, now and after time steps ('''partly done''' in 2013, '''achieved''' in 2014).  
 
-                - no more substitute (domzgr_substitute.h90): all e3 always defined at before, now and after time steps ('''partly done''' in 2013, '''achieved''' in 2014).  
+                !- adapte OFF line for tracer to variable volume (2015?) 
 
-                - adapte OFF line for tracer to variable volume (2015?) 
+'''*''' linear ssh option set without optimization (i.e. starting from the non-linear case with minimal changes, not optimal changes), or linear case suppressed ?? We should probably keep a linear case for test cases. (2014-2015 ?)
 
-'''*''' • linear ssh option set without optimization (i.e. starting from the non-linear case with minimal changes, not optimal changes), or linear case suppressed ?? We should probably keep a linear case for test cases. (2014-2015 ?)
+'''*''' sea-ice : embedded sea-ice as default
 
-'''*''' • sea-ice : embedded sea-ice as default
+                !-  suppress levitating sea ice with virtual salt fluxes. (2014 ?)
 
-                - suppress levitating sea ice with virtual salt fluxes. (2014 ?)
+                !-  Suppress levitating sea ice with mass exchange (?)  CICE issue…
 
-                - Suppress levitating sea ice with mass exchange (?)  CICE issue…
+                !-  need land-fast ice ('''WP 2014''')
 
-                - need land-fast ice ('''planned''' '''2014''')
+                !- need BDY compatibility with embedded sea-ice …. (who when?)
 
-                - need BDY compatibility with embedded sea-ice …. (who when?)
+'''-'''  tracer advection scheme: diminish their number (?). 
 
-'''-''' • tracer advection scheme: diminish their number (?). Typically one module for 2^nd^/4^th^ order and one for a 3^rd^ order scheme, both associated with an optional flux limiter to ensure positivity.
+              !-  Typically one module for 2^nd^/4^th^ order and one for a 3^rd^ order scheme, both associated with an optional flux limiter to ensure positivity. To be discussed
+
+              !- Addition of the rotation of the diffusive part of 3^rd^ order scheme (2015 ?)
 
 '''-''' • vertical physics:  simplification versus diversity