Hi @pia I’ve had a chance to revisit this a bit today based on @Aidan’s comment. I’ve come up with this notebook which seems to have had the desired effect on the means. The hires and lowres means now match, and they’ve increased to a more reasonable 13-17 degrees C now that the polar grid cells are weighted lower.
I acknowledge I’ve probably done this in the least practical way possible, but I’m hoping Cunningham’s Law prevails here and someone else has a better answer.