hi

something wrong happened ,when i make 'LuvSponge == T ;LtracerSponge == T T'...

GET_GRID - error while reading variable: spherical

in grid NetCDF file: ./input/GRID.nc

I use the code "roms_kata_svn". When i close the 'LuvSponge' and 'LtracerSponge', it works well , is thers some bug in the code,or i use the wrong option?

## when I use LtracerSponge , LuvSponge , something wrong

### Re: when I use LtracerSponge , LuvSponge , something wrong

It looks like my version of get_grid.F got a bit scrambled. Try again? I've never used the sponge options, so that code hasn't been tested.

### Re: when I use LtracerSponge , LuvSponge , something wrong

Hernan Arango's add_sponge.m function in the myroms.org Matlab tools will add (or overwrite) the sponge to an existing grid file:

Code: Select all

```
add_sponge: Adds sponge data to a ROMS Grid NetCDF file
add_sponge(ncfile, visc_factor, diff_factor)
Adds enhanced viscosity and diffusion scaling variables (visc_factor
and diff_factor) to an existing ROMS Grid NetCDF file. These scales
are used in an application to set sponge areas with larger horizontal
mixing coefficients for the damping of high frequency noise coming
from open boundary conditions or nesting. In ROMS, these scales are
used as follows:
visc2_r(i,j) = visc2_r(i,j) * visc_factor(i,j)
visc4_r(i,j) = visc4_r(i,j) * visc_factor(i,j)
diff2(i,j,itrc) = diff2(i,j,itrc) * diff_factor(i,j)
diff4(i,j,itrc) = diff4(i,j,itrc) * diff_factor(i,j)
where the variables 'visc_factor' and 'diff_factor' are defined at
RHO-points. Usually, sponges are linearly tapered over several grid
points adjacent to the open boundaries. Its positive values linearly
increase from the inner to outer edges of the sponge. At the interior
of the grid we can values of zero (no mixing) or one (regular mixing).
NOTICE that it is more advantageous to specify these scaling factors
in the ROMS Grid that coding it inside ROMS. We can plot and adjust
their values in an easy way in Matlab.
On Input:
ncfile GRID NetCDF file name (string)
visc_factor Viscosity factor (2D array; nondimensional, positive)
diff_factor Diffusivity factor (2D array; nondimensional, positive)
```

John Wilkin: DMCS Rutgers University

71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu