dude, I downloaded that and it came with the original transparent global cloud map, before that, there was another version that was gray for the places that had no clouds, and white for the places that had clouds, someone find out a way to convert the grey color into transparent and now we have it in the air where it belongs, but we still have the original transparent global cloud map with us, sticked to the ground. we can convert the white of the original transparent global cloud map to black, using the same method that suplants color gray to transparent, this time white, to black. we apply a 50% transparency to the result of black and transparent cloud map, we stick the results to the ground and now we have shadows of the clouds on the ground. it makes a big difference when youre below clouds level.
(or we can just inverse the colors of the global cloud map, stick it to the ground, add a transparency level, and theres the cloud shadows!)