Polarization of reflected light?

[Vay]

My astronomy book says:

 

"When light reflects off a flat, horizontal surface like the ground or a lake, the surface tends to reflect light in which electric field is vibrating along (parallel) to the surface and to transmit or absorb light with electric fields vibrating in other directions. As a result, the reflected light becomes polarized, with its electric field vibrating horizontally."

 

What do they mean by flat "horizontal" surface with regards to the "ground" or "lake"? Is the book saying that the lake and ground has a horizontal surface relative to your positional stance, in that you are standing perpendicular to the ground, such that the ground is horizontal to you, where as you are the vertical? Or is there a deeper meaning to this "horizontal surface"?

 

Furthermore, it follows that these surfaces tend to reflect light polarized in direction of vibration that is parallel to the surface. What I get here is that if a light is vibrating horizontally, then when it hits a horizontal surface(relative to your standing position with respect to the ground), then the horizontally polarized light will reach your eyes. Light waves that are polarized in various other directions, are absorbed by the horizontal surface.

 

So the next question is why do horizontal surfaces absorb light of every polarization and reflect light that is polarized parallel to the ground? can you explain this, using a person standing by a lake with a tree at the opposite bank from where you are standing. And this tree would have reflected unpolarized light at the lake, which the lake then reflects into your eyes. Using this visual example, can you explain the the question from the former sentence of this paragraph?

[swansont]

Reflection is a result of absorption and re-emission of light. This is an electric dipole interaction, with the polarization direction telling you the orientation of the dipole, and dipoles have a specific emission pattern — they do not radiate along their axis. So if you have a flat surface and light polarized parallel and perpendicular to the surface, there is an angle at which the perpendicularly polarized light cannot radiate; this is known as Brewster's angle. Reflection of this polarization is suppressed near this angle as well. Which leaves you with a larger component of the parallel component in the reflected light.