esmg / pycnal_regridding Goto Github PK

Hey, I had to run this on the resultant OBC files:

ncatted -O -a calendar,time,m,c,"gregorian" $file

It would be nice if this happened during file creation.

This is currently discussed in some emails but sedimented into mailboxes.

Do we want to have pycnal computed those terms ?
I think we should be able to compute them outside of this regridding tool.

PyCNAL is able to process as many scalars variables (T,S,ssh) and couple of vector components (u,v), (uice,vice),... If we compute (dv/dx) and (du/dy) fields before passing them to PYCNAL, they
can be treated as either scalar or vector variables.

I think that since u,v and x,y co-rotate, there is no need to rotate these fields. If I am wrong, the option to do it is to pass those field as a new vector variable and use the options :

rotate_velocities=True, rotation_angle='you read it from the ocean_hgrid.nc', Arakawa='B'

NB: since the resulting gradient is on the q-point, both fields are colocated so we want to make
sure that PyCNAL does not re-colocate them (coded for Arakawa='C')

please try different options and let me know what works.

The current PyCNAL uses the interface height of each grid cell to compute the layer thickness. However, the examples only use the cell center depth instead of cell interface height as input for the PyCNAL to computer layer thickness. This may cause issues to layer thickness in boundary files.

In the PyCNAL, depth is computed using interface height
lib_ioncdf.py, line 348: dz[:-1, :, :] = vc[1:, :, :] - vc[:-1, :, :]

In the PyCNAL examples, only cell center depth is provided:
Creating_Initial_and_Boundary_conditions_from_SODA3.py, line 59:
salt_domain.interpolate_from(sodaic,'salt',frame=0,depthname='st_ocean',coord_names=['xt_ocean','yt_ocean'],

@raphaeldussin We will obsolete "brushcutter" mode when this code can make boundary conditions that are no longer on the supergrid. We want information on the velocity points along the boundary, not at the q points (until we need q at the q points).