Changes between Version 23 and Version 24 of 2009WP/2009Stream3

Timestamp:

2009-10-21T08:14:02+02:00 (15 years ago)

Author:

sga

Comment:

--

2009WP/2009Stream3

@@ -74 +74 @@
 === S3.2-e — Lateral ocean physics ===
 
-        '''Motivation:'''  Griffies's implementation of the Gent and  McWilliams eddy transport as a skew flux is being implemented. This has the advantage that  its numerical discretization can be written in terms of contributions  from quarter cells – ‘triads’. This gives a tighter stencil,  disallowing 2-gridpoint numerical noise that is permitted by the  advective discretization. Isopycnal diffusion is also being  discretized in terms of these triads, obviating the need to smooth  isopycnal slopes horizontally with a Shapiro filter (as currently  implemented in NEMO), or apply a background horizontal diffusivity  that would mix diapycnally. Visbeck et al.'s formulation of spatially varying  diffusivities is also being implemented, as an alternative to the current formulation based on  the Held and Larichev timescale and the Rossby radius as a  lengthscale. Mixed-layer depth is sensitive to the slope limiting that  is employed, and a slope limiting algorithm will be employed that  behaves satisfactorily within and immediately below the mixed layer. [[BR]]
+        '''Motivation:'''  Griffies's implementation of the Gent and  McWilliams eddy transport as a skew flux is being implemented. This has the advantage that  its numerical discretization can be written in terms of contributions  from quarter cells – ‘triads’. This gives a tighter stencil,  disallowing 2-gridpoint numerical noise that is permitted by the  advective discretization. Isopycnal diffusion is also being  discretized in terms of these triads, obviating the need to smooth  isopycnal slopes horizontally with a Shapiro filter (as currently  implemented in NEMO), or apply a background horizontal diffusivity  that would mix diapycnally. Visbeck et al.'s formulation of spatially varying  diffusivities is also being implemented, as an alternative to the current formulation based on  the Held and Larichev timescale and the Rossby radius as a  lengthscale. Mixed-layer depth is sensitive to the slope limiting that  is employed, and a slope limiting algorithm will be added that  behaves satisfactorily within and immediately below the mixed layer. [[BR]]
 
         '''Status: ''' Working prototype code for the iso-neutral and skew-flux operator is under revision at NOCS and will be ready for the 3.3 release. Considerable care has been taken in the formulation to ensure the tensorial representation is consistent with the variable volume layers (S-coordinate/z* representation). This has been documented and will be provided with the release. Process model studies with this code have been successfully completed. Options for slope limiting have been considered and will be thoroughly tested before release.  [[BR]]