gistfile1.txt

In [62]: empty = xr.DataArray(zed, dims=['ageclass', 'pointspec', 'time', 'latitude', 'longitude'], coords={'time':taxis, 'latitude': dset.l
    ...: atitude, 'longitude':dset.longitude})

In [63]: empty
Out[63]: 
<xarray.DataArray (ageclass: 1, pointspec: 1, time: 2557, latitude: 360, longitude: 720)>
array([[[[[ 0., ...,  0.],
          ..., 
          [ 0., ...,  0.]],

         ..., 
         [[ 0., ...,  0.],
          ..., 
          [ 0., ...,  0.]]]]])
Coordinates:
  * latitude   (latitude) float32 -89.75 -89.25 -88.75 -88.25 -87.75 -87.25 ...
  * time       (time) datetime64[ns] 2007-01-01 2007-01-02 2007-01-03 ...
  * longitude  (longitude) float32 -178.75 -178.25 -177.75 -177.25 -176.75 ...
Dimensions without coordinates: ageclass, pointspec

In [64]: empty[dict(time=dset.WD_spec001.time[1:])] = np.diff(dset.WD_spec001 + dset.DD_spec001)

ValueError: invalid subkey array(['2008-03-03T00:00:00.000000000', '2008-03-04T00:00:00.000000000',
       '2008-03-05T00:00:00.000000000', '2008-03-06T00:00:00.000000000',
       '2008-03-07T00:00:00.000000000', '2008-03-08T00:00:00.000000000',
       '2008-03-09T00:00:00.000000000', '2008-03-10T00:00:00.000000000',
       '2008-03-11T00:00:00.000000000', '2008-03-12T00:00:00.000000000',
       '2008-03-13T00:00:00.000000000', '2008-03-14T00:00:00.000000000',
       '2008-03-15T00:00:00.000000000', '2008-03-16T00:00:00.000000000',
       '2008-03-17T00:00:00.000000000', '2008-03-18T00:00:00.000000000',
       '2008-03-19T00:00:00.000000000', '2008-03-20T00:00:00.000000000',
       '2008-03-21T00:00:00.000000000', '2008-03-22T00:00:00.000000000',
       '2008-03-23T00:00:00.000000000', '2008-03-24T00:00:00.000000000',
       '2008-03-25T00:00:00.000000000', '2008-03-26T00:00:00.000000000',
       '2008-03-27T00:00:00.000000000', '2008-03-28T00:00:00.000000000',
       '2008-03-29T00:00:00.000000000', '2008-03-30T00:00:00.000000000',
       '2008-03-31T00:00:00.000000000', '2008-04-01T00:00:00.000000000',
       '2008-04-02T00:00:00.000000000', '2008-04-03T00:00:00.000000000',
       '2008-04-04T00:00:00.000000000', '2008-04-05T00:00:00.000000000',
       '2008-04-06T00:00:00.000000000', '2008-04-07T00:00:00.000000000',
       '2008-04-08T00:00:00.000000000', '2008-04-09T00:00:00.000000000',
       '2008-04-10T00:00:00.000000000', '2008-04-11T00:00:00.000000000',
       '2008-04-12T00:00:00.000000000', '2008-04-13T00:00:00.000000000',
       '2008-04-14T00:00:00.000000000', '2008-04-15T00:00:00.000000000',
       '2008-04-16T00:00:00.000000000', '2008-04-17T00:00:00.000000000',
       '2008-04-18T00:00:00.000000000', '2008-04-19T00:00:00.000000000',
       '2008-04-20T00:00:00.000000000', '2008-04-21T00:00:00.000000000',
       '2008-04-22T00:00:00.000000000', '2008-04-23T00:00:00.000000000',
       '2008-04-24T00:00:00.000000000', '2008-04-25T00:00:00.000000000',
       '2008-04-26T00:00:00.000000000', '2008-04-27T00:00:00.000000000',
       '2008-04-28T00:00:00.000000000', '2008-04-29T00:00:00.000000000',
       '2008-04-30T00:00:00.000000000', '2008-05-01T00:00:00.000000000'], dtype='datetime64[ns]') for integer based array indexing; all subkeys must be slices, integers or sequences of integers or Booleans