Aaah, an entry in the animation section!!!!
Cool! Very nice!! Calm and beautiful. I'd say, if you'd render your animation in better quality (and larger) the flickering would look much more natural.
You could then cheat a bit. If you have access to a compositing program you could use some frame blending to reduce the flicker even more.
But as Luvsmuzik wrote, a certain amount of flicker occurs in the real world.