Photo: Brunt Ice Shelf As Seen From Orbit

This Envisat image features the Brunt Ice Shelf lying against the Weddell Sea on the coast of northern Coats Land in Antarctica. The Brunt Ice Shelf is a 100-m-thick floating area of ice that is fed mainly by ice flowing from Dronning Maud Land.

The ice shelf moves several hundred metres a year towards the ocean. Once it reaches the Weddell Sea, it is put under strain from higher temperatures and the motion of tides until parts of it eventually break off into icebergs.

Since the mid-1950s the ice shelf has been home to the British Antarctic Survey’s Halley Field Station. As the ice shelf moves, it takes Halley station with it. In fact, the station drifts northwest by half a kilometre each year.

The ice shelf is not thought to be in a steady state. It is at risk of calving, from extending cracks and impacting icebergs. If the ice shelf breaks away from the peninsula, it will not cause a rise in sea level since it is already floating.

Studying ice shelves is important because they are indicators for ongoing climate change. Long-term satellite monitoring over Antarctica is essential because it provides authoritative evidence of trends and allows scientists to make predictions.

Over the last 20 years, ESA’s ERS and Envisat satellite missions have been the main vehicles for testing and demonstrating the use of Earth observation data in polar regions.

Envisat’s Advanced Synthetic Aperture Radar (ASAR) instrument is particularly suited to acquire data over Antarctica because it is able to see through clouds and darkness – conditions often found in the area. Daily ASAR images of Antarctica are made easily accessible to scientists.

Also visible is the ice covered Lyddan Island, which with its 3 narrow arms resembles the tail of a whale.

This image was acquired by ASAR on 5 March. Larger image.