This image combining two scans by Sentinel-1A’s radar shows that parts of the Pine Island glacier flowed about 100 m (in pink) between 3 March and 15 March 2015. Light blue represents stable ice on either side of the stream.
Pine Island is the largest glacier in the West Antarctic Ice Sheet and one of the fastest ice streams on the continent, with an average of over 4 km per year. About a tenth of the ice sheet drains out to the sea by way of this glacier.
With its all-weather, day and night radar vision, the Sentinel-1 mission is an important tool for monitoring polar regions and the effects that climate change has on ice. You can see more images from Sentinel-1A on ESA’s website.