Use Polymer-based atmospheric correction for water surfaces.

AWI Bremerhaven is developing an atmospheric correction for water surfaces based on Polymer. This has to be implemented into EnPT. So far, SICOR is running for all pixels of the input image, regardless of whether they contain land or water surfaces.

Steps to be done:

• implement water AC provided as an external Python package
• check ability of SICOR / water-AC to apply the algorithm only to pixels selected by a binary mask
• use water masks provided by the ground segment to decide which AC has to be applied where
• implement an algorithm to fuse the results of SICOR and the water AC to a single reflectance product
• provide config parameters to run EnPT in 3 modes: water+land, land-only, water-only
• include the new config parameters into the EnPT GUI
• decide which radiometric unit will be contained in the L2A product for water surfaces (water leaving radiance/reflectance, surface reflectance) -> ground segment L2A product contains surface reflectance but this is not a commonly used rad. unit in the water community
• add documentation on water AC (and possibly a radiometric output unit different to the L2A product of the ground segment)