Error merging and opening .nc files in projections-cmip6.ipynb

[maxduganknight]

In running through the projections-cmip6.ipynb file I get an error at the following line:

data_ds = xr.open_mfdataset(f'{DATADIR}cmip6_agg*.nc')

Here's the error:

---

ValueError Traceback (most recent call last)
Cell In[50], line 1
----> 1 data_ds = xr.open_mfdataset(f'{DATADIR}cmip6_agg*.nc')

File ~/.pyenv/versions/3.12.1/lib/python3.12/site-packages/xarray/backends/api.py:968, in open_mfdataset(paths, chunks, concat_dim, compat, preprocess, engine, lock, data_vars, coords, combine, parallel, join, attrs_file, **kwargs)
955 combined = _nested_combine(
956 datasets,
957 concat_dims=concat_dim,
(...)
963 combine_attrs="drop",
964 )
965 elif combine == "by_coords":
966 # Redo ordering from coordinates, ignoring how they were ordered
967 # previously
--> 968 combined = combine_by_coords(
969 datasets,
970 compat=compat,
971 data_vars=data_vars,
972 coords=coords,
973 join=join,
974 combine_attrs="drop",
975 )
976 else:
977 raise ValueError(
...
(...)
803 combine_attrs=combine_attrs,
804 )

ValueError: Resulting object does not have monotonic global indexes along dimension year

It seems like this may be an issue in the data downloaded from Copernicus. Any suggestions on how to get past this? Thanks

[myneur]

I had the same problem. Identifying nesting dimensions solved it for me.

data_ds = xr.open_mfdataset(f'{DATADIR}cmip6_agg_*.nc', combine='nested', concat_dim='model')