Regridding to reference dataset fails sometimes #56
Description
Not an urgent issue, but something I noticed:
Regridding to a reference dataset, e.g.
regrid_to_ref:
regrid:
target_grid: GFDL-CM3
scheme: linearinvokes a simple iris.load_cube
on the raw nc file, which may fail in rare cases if the file contains multiple variables (e.g rsdt of GFDL-CM3), which leads to errors like this:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "~/anaconda3/envs/esmvaltool/lib/python3.6/site-packages/iris/__init__.py", line 376, in load_cube
raise iris.exceptions.ConstraintMismatchError(str(e))
iris.exceptions.ConstraintMismatchError: failed to merge into a single cube.
cube.long_name differs: 'Length of average period' != 'End time for average period'
cube.var_name differs: 'average_DT' != 'average_T2'
cube.units differs: Unit('days') != Unit('days since 1860-01-01 00:00:00', calendar='gregorian')
I think we need an advanced loading function here.