I am working on processing some Sentinel 1 images in Alaska and am trying to use an external DEM. I was hoping to use the Arctic DEM: https://www.pgc.umn.edu/data/arcticdem/, but have had quite a hard time so far.
I have downloaded the appropriate tiles from the website, merged and clipped them to the area I am interested in, but am now trying to project this DEM into GCS_WGS_1984 from Polar_Stereographic using ArcMap before terrain flattening with this DEM. However it is giving me no options for geographic transformations. What am I missing? Could I leave this DEM in polar_stereographic for terrain flattening?