Graduation Robes - What accolades does this guy have? I am currently at my brother's graduation ceremony at Adelaide University, and in the Professor's/Post-grad seating area, sits a man fully in green. What does this special gown mean?

(Apologies for the awful picture)
It is conventional in many places for faculty who participate in a graduation ceremony to wear the regalia from the university where they got their degree. Some universities have more... elaborate regalia than others.(See e.g. Etiquette of wearing the wrong academic robes at graduation as a lecturer in the UK, especially this comment. And this.)

Others sitting on stage in your photos appear to be wearing the Adelaide University regalia - maybe that's where they did their doctorate (or they did it at a university that uses the same regalia), or maybe they don't have the regalia from their alma mater and just wear this one.