Load data in parallel using dask.

climax/main/preprocess.py

@@ -174,7 +174,7 @@ if __name__ == '__main__':
                     ['{}'.format(file) for file in group]))
 
                 # read multiple netcdf files using xarray and dask
-                ds = xr.open_mfdataset(group).load()
+                ds = xr.open_mfdataset(group, parallel=True).compute()
 
                 # save aggregated netcdf file
                 LOGGER.info('Saving aggregated NetCDF: {}'.format(filename))