A question regarding cpp option: ONLINE


The CROCO manual says that with the cpp option, ONLINE, CROCO will interpolate forcing files to CROCO grids online. I assume this is the same function as the Rutgers’ ROMS saving storage as CROCO does not need the forcing files interpolated to CROCO grids. I want to use it to save some storage as interpolated forcing file (0.25 deg to <1 km) is rather big and wastes storage space.

However, there is no instruction on how to prepare the “native files”. Can someone show me the metadata of the forcing netcdf (the output of ncdump -h)? I am trying to use ERA5 on this. I’ve already downloaded ERA5 data, but I think the “native files” are not the ones I downloaded.

Read native files and perform
online interpolation on CROCO | grid
(default cubic interpolation)

Thanks in advance.


Hi all,

It looks like all we need is the ERA 5 files downloaded from the ECMWF site and define ONLINE and ERA_ECMWF, and BULK_FLUX in cppdefs.h

In online_bulk_var.F, there is a list of variable names (t2m, q, ssr, strd, u10m, v10m) which are consistent with ERA5 data. So I assume I put the ERA 5 file under forcing in croco.in and CROCO will read the data from the ones downloaded from ECMWF and interpolate and process the forcing data online.

If I had a problem when running the CROCO model, I will update it.