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It actually does not absorb radar energy, rather it reflects it away (specular reflection). That's why rougher sea surface appears brighter on SAR as it turns f
by m2fkxy 3y ago
It actually does not absorb radar energy, rather it reflects it away (specular reflection). That's why rougher sea surface appears brighter on SAR as it turns from a specular to a diffuse scatterer. Furthermore, in some specific conditions (low incidence angle, closer to nadir), calm water can appear much brighter than other land surfaces.
- enriquto 3y agothanks for the clarification! I'm just used to looking to the images without thinking too much about the water. I've never seen "close to nadir" radar images... wouldn't the ground fold over itself?
- m2fkxy 3y agoNadir-SAR would look very confusing, full of ambiguities, and probably unexploitable since the ranging part of RADAR would not be able to distinguish the left returns from the right returns -- that's why SAR is side-looking. even with a strictly side-looking geometry, images collected closer to nadir (steep/low incidence) start exhibiting some artifacts such as nadir returns [1]. [1] https://www.researchgate.net/figure/Example-of-nadir-echo-in-a-SAR-image-acquired-by-the-TerraSAR-X-satellite-over_fig1_324030571 https://www.researchgate.net/figure/Example-of-nadir-echo-in...