title: Xarray - concatenating slices from multiple files
body: <p>I'm attempting to concatenate slices of multiple files into one file (initialized by a zeros array) and then write to a nCDF file.  However, I receive the error:  </p>
  
  <pre><code>arguments without labels along dimension 'Time' cannot be aligned 
  because they have different dimension sizes: {365, 30}
  </code></pre>
  
  <p>I understand the error (the isel() changes the size of the dimension to the size of the slice), however I don't know how to correct or circumvent the problem.  Am I approaching this task correctly?  Here's a simplified version of the first iteration:</p>
  
  <pre><code>import xarray as xr
  import numpy as np
  
  i=0
  
  PRCP = np.zeros((365,327,348))
  
  d = xr.open_dataset("/Path")
  
  d = d.isel(Time=slice(0,-1,24))
  
  P = d['CUMPRCP'].values
  
  DinM = P.shape[0]
  
  PRCP[i:i+DinM,:,:] = P
  
  i = i + DinM
  
  PRCPxr = xr.DataArray(PRCP.astype('float32'),dims=[('Time'), 
  'south_north', 'west_east']) 
  
  d['DPRCP'] = PRCPxr
  </code></pre>