Code Sample

frost_run = xr.open_dataarray("nam.grib2", engine="pynio", backend_kwargs={"SingleElementDimensions": "Initial_time"})
# or
import Nio
nio_options = Nio.options()
nio_options.SingleElementDimensions = "Initial_time"
frost_run = xr.open_dataarray("nam.grib2", engine="pynio", backend_kwargs={"options": nio_options})

Problem description

The problem is that there is not a way through xarray to set the PyNio specific options, and I have confirmed by taking a look at the initializer signature of NioDataStore

def __init__(self, filename, mode='r', autoclose=False):

Which does not provide a way to specify that value of the options parameter of the Nio.open_file method it uses

The only workaround is modify the global defaults for Nio prior to opening, i.e.,

import Nio
Nio.option_defaults["SingleElementDimensions"] = "Initial_time"
# open datasets now

Expected Output

Either way from the sample results in TypeError: __init__() got an unexpected keyword argument

Output of xr.show_versions()