Load common grid avoiding to change origin of coordinates to zero
I add here the comment from Virgine about Load:
To me the default behaviour of Load of interpolating observations and model data to a common grid, is absolutely essential to avoid errors. In particular, even when the grids in the observations and models have the same number of latitude and longitude, Load checks whether the longitudes are aligned and re-interpolate the data to a common grid with the first longitude being 0. These checks are crucial because some grids are very commonly used, such as the 1degree regular grid (360x180) but they are not always centered identically (-180 to 180 or 0 to 360) and if the model and observational grids were shifted by only 0.5 degrees (for example, model going from 0 to 359 and obs from 0.5 to 359.5), this error would be hard to find out but could generate a substantial loss in prediction skill.
Only, what Load does is not exactly checking whether the longitudes are aligned but rather checking whether the first longitude is 0 and if it is not 0, it re-interpolates the data to a grid with the first longitude being 0. However, you could have regular grids in both models and data that are aligned but with a longitude that does not start from 0. For example, you could have all data on a common grid with longitudes going from -180 to 180. What Load could do instead of checking whether the first longitude is 0 is rather checking whether the first longitude is the same in all models and observations and interpolate only if one of the dataset is not aligned with the other. If one dataset is not aligned, you could interpolate it toward the grid of the other datasets (or easier the first dataset). To do so, you would do cdo remapcon,/path/to/file/filename1ofdataset1.nc filedataset2.nc fileout.nc instead of cdo remapcon,r360x180 filedataset2.nc fileout.nc
I think we should check how Load checks the cordinates to evaluate how difficult this development will be. The documentation also mentions that if no grid is specified, the grid from the first experimental dataset is used, but I don't know if it uses the path to the file or reads the grid and uses 'rYYYxZZZ'.
We could talk soon and see how to proceed.