It runs Cray Linux (based on SUSE) and assuredly somebody is running Fortran on it in some form.

Many people think these large machines are intended for a small handful of users that run extremely large jobs. That's typically not the case; they typically have tens of users per day up to hundreds per week, depending on institution. With diverse users comes diverse software and the challenges based on that.

Not sure exactly what you're after here. The systems have assorted versions of Fortran compilers from both Cray and Intel. With regards to versions of the language standard used/ required for the models I'm not sure.