Need help understanding this satellite image of Larson C ice shelf The false color image below shows synthetic aperture radar imaging from ESA's Sentinel-1 satellite. The map from the 20-Jan-2017 BBC article Larsen ice crack continues to open up illustrates the same general area.

The Larson C Ice Shelf is the large blue-ish region in the middle of the false-color radar image, and is labeled as such. The crack is the thin lighter line just above the red arrow.

Moving diagonally upwards to the right, the gray region is labeled "Sea Ice". Is this just much thinner but mostly solid ice, or water with pieces of ice in it? While the ice shelf seems relatively uniform in tone, the gray sea ice area has a mottled pattern.

Also the boundary between the two regions has what looks to me like some kind of 3D effect - the black, ribbon-like variable width region separating the two. Is this an effect of shadowing from oblique incidence? Is this actually the sidewall height of the ice shelf?

There is also some discussion of radar imaging of sea ice in this answer.



above: Cropped and enlarged highlight from Sentinel-1 synthetic aperture radar image of the Larson C ice shelf, beginning of January 2017, found here. Image credit: ESA/EU/Copernicus



above: Sentinel-1 synthetic aperture radar image of the Larson C ice shelf, beginning of January 2017, found here. Open in separate viewer or tab for full size. The width of the image is roughly 300km, south is towards the lower right. Image credit: ESA/EU/Copernicus



above: Map of the region around the Larson C ice shelf, beginning of January 2017, from BBC here. Image credit: MIDAS Project, A. Luckman, Swansea University. Because it's difficult to read, I'll point out that Wales not shown in it's correct location - it's there for scale only.
I found a natural-color image of the same area: 68.28 South, 60.47 East, North is up, resolution is 130m/px, which makes the whole image about 100 km x 100 km. Looking at the image i'd say that:


sea ice is water with pieces of ice in it,
the boundary between the two regions is clear water, probably caused by winds and currents moving the floating ice away from the edge of the ice shelf.


I got the image at Sentinel Playground using 100% cloud filter, 0.3 gain and date selection of 2016-11-21.

EDIT: Added more info about the position, scale and orientation of the image.