Hi,
what do you mean with NetCDF, do you mean NetCDF with the Ugird standard?
You use an unstructured mesh in Telemac, so far I know the standard NetCDF supports no unstructured meshes. There is a proposal (ugrid) for unstructured meshes.
Usually you have to convert/interpolate your data on a structured mesh. I think it is no good idea to do particle tracking on an interpolated set of data? Maybe this depends on your tracking algorithm.
If you use the search button you will find some more posts about NetCDF in the forum.
Best regards
Leo