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## Homework Statement

An underwater observer is looking directly into the sun. His head is near, but below the surface, and he is not wearingsun glasses. Let L

_{s}(x) be the solar radiance at the water surface, on the air side, when the sun is at a zenith angle x. What is the ratio of the solar radiance at the observer's eye to the solar radiance just above the water surface?

## Homework Equations

Here's where I'm having trouble. I'm not sure which equation is relevant. Is this simply a Fresnel transmission problem? I have equations for vertical and horizontal polarization

Rh = [sin

^{2}(x

_{a}- x

_{w})]/[sin

^{2}(x

_{a}+ x

_{w})]

But I also have a solid angle formula for radiance at the air water boundary. It is labeled "From Snell's law and flux conservation" [tex]\Omega[/tex]

_{a}= n

^{2}[cos x

_{w}/ cos x

_{a}] [tex]\Omega[/tex]

_{w}

Where the [tex]\Omega[/tex]s are solid angle. The subscript a one is subtended by L

_{s}in the accompanying diagram. And the subscript w by L

_{d}(downwelling) so I'm not sure if this ratio would be what I need.

Any thoughts?

Thanks for your help!!!!