Good, but needs a little more realism.
It does convey the sense that you are underwater looking up at the sun through the surface. However, since it looks like you're going for a sense of realism(I'll at least assume it), more detail is needed, such as the glare of the sun on the surface. I'm not sure, but I think that the glare should be circular, not oval. And if there are any kind of waves up there, the glare should be speckled and distorted.
#1. I don't know which perspective you're going for, but the darker region near the bottom(unless it's a shadow on the surface) makes it seem like a horizontal view. So then the sun has to be somewhere in its rise or descent.
#2. Those wavy lines--are they supposed to be the weird lines you get on the base of a pool in the sun? Because they usually only appear on solid object under or near water, not in the water itself.
#3. The rays of light coming down look perfect...except that a couple of them might be crooked. Rays usually travel in a straight line.
Hope this review helped. I'd be glad to review other work, too.