[MITgcm-support] cheapAML + global_oce_llc90

[Jean-Michel Campin]

Hi Gus,

There might be some issues when trying to use cheapAML on llc90 grid: 
The advantage of the lat-lon-cap grid (e.g. llc90) versus a regular 
cubed-sphere grid of similar resolution is that face corners
(where grid-cells are the smallest and deviation for orthogonal grid
is the largest) are moved over land. However, cheapAML does need to compute
advection everywhere, including over land, and this might put a strong
constrain on the cheapAML time-step you use.

otherwise, I made some comments below.

On Tue, Aug 09, 2016 at 03:28:13PM -0400, Gus Correa wrote:
> Dear MITgcm pros
> 
> Our group wants to run the MITgcm global_oce_llc90 configuration
> forced through the cheapAML package.
> 
> There is little documentation on the cheapAML and the verification
> example is too simple to be of help (one-level box model,
> analytic formula winds, no input files other than bathymetry).
> 
> We read Deramble et al. cheapAML article, but it doesn't
> go into the nitty-gritty details of model setup that we need.
> http://ocean.fsu.edu/~bderembl/pub/cheapaml_mwr.pdf
> 
> Questions:
> 
> 1) Do the cheapAML input files (Uwind, Vwind,
> downwelling shortwave, etc) need to be regridded to the LLC90 grid,
> or can they be lat-lon files?
> [This may be wishful thinking ...]

they should all be on model grid.

> 2) More realistically, if regridding to LLC90 is needed,
> are there any tools available for that?
> [I looked at the gcmfaces package, but it is unclear if it will do it
> and how.]
> 
> 3) Is there anybody that has ran the cheapAML along with a
> realistic global ocean,
> even if on a lat-lon grid (say, global_ocean.90x40x15),
> who could give us some clues on how to get started?

I thought that a "realistic" ocean set-up was including in Deremble etal, 2013
paper (section 4). In fact, most of the default parameter in pkg/cheapaml are
relevant to this type of config.

Cheers,
Jean-Michel

> Any suggestions are appreciated.
> 
> Many thanks
> Gus Correa
> LDEO
> 
> 
> 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support