Albedo at high angles of incident light such as those that occur on the illuminated side of Earth near the terminator (early morning, late afternoon, and near the poles). However, as mentioned above, waviness causes an appreciable reduction. Because light specularly reflected from water does not usually reach the viewer, water is usually considered to have a very low albedo in spite of its high reflectivity at high angles of incident light. Note that white caps on waves look white (and have high albedo) because the water is foamed up, so there are many superimposed bubble surfaces which reflect, adding up
Incompressible surface Incompressible surface In mathematics, an incompressible surface is a surface properly embedded in a 3-manifold, which, in intuitive terms, is a "nontrivial" surface that has been simplified as much as possible by compressing disks. They are useful for decomposition of Haken manifolds and for normal surface theory. Let "S" be a compact surface properly embedded in a smooth or PL 3-manifold "M", and suppose that there is a disk "D" embedded in "M" such that where the curve ∂"D" does not bound a disk inside of "S". Then "D" is called a compressing disk for "S", and we call "S"