Nesting issue along the child boundary - A quick Solution

nesting
1

Perhaps some of you have encountered this feature along the child boundary when running a 2-ways nesting experiment.

In the attached figure, I am showing on the left the SSH 5 days after initialization of a 2 ways nesting experiment.
As you can see, there are some weird/unrealistic SSH errors along the boundary (magenta line).
(In this particular example, the parent grid is 1/2 degree resolution, the child has a 1/6 degree resolution)
By the way, this error does not seem to propagate

On the right is a quick fix that seems to work.
In the cppdef_dev.h, I define the following:


define AGRIF_UPDATE_MIX


define AGRIF_UPDATE_DECAL (This one is undefined by default)

I have not really looked at it in detailed, but maybe this could help some of the croco users.

cheers,

Vincent

image description

2

Hi Vincent, this is useful. in Debreu et al. (2012), AGRIF_UPDATE_DECAL gave the best results on the Vortex text case. However, in some cases (not all obviously) it was found to affect the SSH child solution and it was recently left undefined by default for this reason (it is also undefined in the NEMO code). Your example shows that we should look at it again and at least be aware … Patrick