Observing the Earth from space

As mentioned in a recent post, the Earth's atmosphere makes everything appear bluish from space. To obtain rich, colorful satellite imagery in which the ground vegetation appears naturally green, color correction must be done to remove the bluish tint. There is a nice tutorial from NASA on how to do that here.

Because I'm using BMNG imagery for my base texture, the source data has already gone through such color correction process by NASA personnel. My work would be to reverse the process by adding an atmosphere on top and therefore re-introducing a bluish tint.

I have a difficult time deciding how much "atmospheric blue" is enough to make the renders look realistic and still naturally colorful. I do have a dial for the amount of atmospheric density, but it seems that there is no single setting that will work with all viewing distances and angles. More research needed in this area... :/

Meanwhile, here's another work-in-progress shot (dated 28 Sept 2011) compared with a still frame from a NASA video filmed from the ISS. The texture is satellite imagery from BMNG January 2004, and we are looking south down at the Rocky Mountains on the North American continent, with the Pacific Ocean to the right: