@martindurant - If I understand your question correctly, I think you should be able to follow a pretty standard xarray workflow:

```Python ds = xr.Dataset() ds['your_varname'] = xr.DataArray(some_dask_array, dims=['dimname0', 'dimname1', ...], coords=dict_of_preknown_coords)

repeat for each variable you want in your dataset

ds.to_zarr(some_zarr_store)

then to open

ds2 = xr.open_zarr(some_zarr_store) ```

Two things to note:

1) if you are looking for decent performance when writing to a remote store, make sure you're working off xarray@master as #1800 fixed a number of choke points in the to_zarr implementation 2) if you are pushing to GCS, some_zarr_store can be a GCSMap.