Earths Curvature + Atmospheric Refraction


I've used sky domes and curved horizon planes before but now I need to show accurate images and animations which include the Earth's curvature and atmospheric refraction.
I can't seem to find detailed info on either of these. I've been using global mapper to get my accurate terrain data and import it into max but was unsure how i'd get the correct earth's curve. I was looking for an option in the vray camera settings but i've hit a wall. If there is a script out there which can calculate the earths curve and or atmospheric refraction in max scenes please forward it on.

Thanks, any help would be appreciated!