To my knowledge, it is not a scientifically validated resolution in land-only mode (I-cases).
There seem to be several listed versions of 0.5 degree, for example, "hcru_hcru", "f05_g17", and "f05_f05_mg17.
However, I did try to set up some cases with those resolutions and there are no available surface datasets, "fsurdat", for those resolutions.
So you would have to create your own surface datasets, and possibly other datasets to run at that resolution.