HYGEOS support forum

Hi,
We are using POLYMER to retrieve Rrs in several Arctic regions, and were wondering how POLYMER treats ice.
For example, I am attaching a scene from OLI from Norton sound (North of the Yukon River delta) processed with POLYMER and ACOLITE as well as the RGB figure.
We can see that most of the region is ice covered, which is flagged out in acolite, but in POLYMER the Rrs is retrieved.

Happy to hear any input on this.
Thank you,
Jonathan

Dear Jonathan,

Polymer treats ice pixels the same way it treats clouds - in that regard, partial ice coverage can be corrected by Polymer, and thick ice blocks should be flagged as clouds, based on a simple cloud mask based on pixel reflectance in the NIR and standard deviation over a block of pixels.
If you want more fine-grained pixel flagging, I would recommend to use IdePix (https://www.brockmann-consult.de/portfolio/idepix/).
By design, Acolite is more sensitive to ice contamination, and more generally, more sensitive to heterogeneous atmospheric or surface contamination than Polymer.
Cheers,
François