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Prydz Bay, East Antarctica, Region east of the Amery Ice Shelf

Date of acquisition:     January 22nd, 2021  | 03:47:36 UTC

Sensor:  Sentinel-2 L2A

Coordinates:    68.05°S, 79.4°E

In this example, fast ice with small icebergs frozen into it is shown. This is not only a very beautiful, visually quite “dramatic” fragment, but it is also interesting  because of it´s origins.

Note the long dark streaks that extend from the icebergs in one direction along the ice. The darkness of the stripes fades with the distance from the icebergs. The length of the strips correlates with the size of the icebergs and for some extends up to 3 km. What could it be?

One option for explanation could be that  this is the result of icebergs melting under water. Since, as commonly known, the largest proportion of icebergs is below the water surface, they protrude downwards from the fast ice, are washed by salty relatively warm water and thaw. Fresh water (being lighter) rises and melts the fast ice. It becomes thinner and therefore more transparent andthe dark seawater shines through it. Since, obviously, there is a rather weak laminar flow in water, stripes with a gradually decaying intensity are formed until the concentration of fresh water becomes negligible.

What’s your opinion on this phenomenon?

Images contain modified Copernicus Sentinel data [2021].