Animation with Back Clip

I´m working with an animation covering an area of 13km. Everything is set up and I´m using a back-clip of 2km which gives me a good frame count (less than 1 frame/minute)

 

The problem is though, that when my scene actually gets clipped (no surprise) at 2km, counting from where the camera was when it generated the first frame. Is there some way to set the clip distance in relation to the cameras position or is there some way to work around this? To set the back clip to 13 km gives me a frame count of approx 1 frame every 12 minutes!!

 

Any suggestions are welcome!

/Dan