I guess I can see how the Doppler effect might work differently vertically versus laterally. Never thought about that...
I always thought it was pretty neat (in a kind of creepy way) that the speed of sound underwater is so much faster than above water, your brain cannot tell which ear detects sound before the other. As a result, the perceived direction any and all sounds have underwater is... directly between your ears.
when scuba diving, it is rather unnerving to hear a passing boat engine rise and fall, with Doppler effect, all coming from the middle of your own head.