The CORe analysis are freely available according to NOAA policy.
The exception are the observations which may contain restricted
observations.  (Observations are in the prepbufr and diag files.)
My unofficial, non-lawyer interpretation of the NOAA policy is that 
acknowledgement is good, calling it "your" product is bad, and NOAA 
is not liable for any damages.   

The sea ice and SST (most locations) are from OSTIA (UK Met Office).