Query regarding sponge width

[tara]

Hello to all,

Can anyone tell me in ROMS 3.7 version how (on the basis of which criteria) and where we can define the sponge width?
From previous forum discussion topics I got that it is defined on the resolution. If yes then what should be the preferred ratio between model resolution and sponge width.


With Best Regards-
Tara

[kate]

In ROMS/Functionals/ana_sponge.h, there are some examples of setting up the sponge. For the Adriatic, the width is 6 grid cells, so it depends automatically on the grid spacing.

[tara]

Thank you very much Kate. So now if my model resolution is 14km then the sponge can be a multiple of 14 so it will be good to give a value as 84 km right? Whether it is dependent or independent of regions and domain?

[kate]

Yes, sure. However, what is the purpose of your sponge? I haven't tried one in many, many years. We use nudging to "climatology" from outside instead of a sponge. Some people call that latter use a sponge, but in ROMS, a sponge is a band of increased viscosity.