Greenland’s changing landscape

Petermann Glacier and iceberg

A massive iceberg broke from the Petermann Glacier in Greenland on August 5.

On August 5, 2010, the unassuming Petermann Glacier on Greenland’s northwestern coast hit the world’s headlines when a huge ice island “calved” from it and started drifting down a fjord.

Eleven days later, the island was continuing its slow migration down the fjord. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured a natural-colour image (above) on August 16, 2010.

Although slivers of ice had loosened around its edges, the ice island had largely retained its original shape. The island, which had rotated counterclockwise since the calving, also retained the crevassed structure of the Petermann Glacier; both the glacier and the ice island sport rippled surfaces.

Thin longitudinal cracks appear on the ice island surface, and wider lateral cracks push in from the island’s sides. An uneven line of pools, medium blue in colour, runs down the length of the ice island.

Along the glacier’s new front, some smaller icebergs appear to have broken free, and ice fragments litter the water surface between the ice island and the glacier. Also visible in the image are multiple small glaciers that feed the Petermann, flowing down to the massive glacier from the northeastern side of the fjord.

See the full-size, high-resolution image here (4MB, new window).

Phytoplankton bloom off the east coast of Greenland.

Satellite image of a phytoplankton bloom off the east coast of Greenland.

Meanwhile, on Greenland’s eastern seaboard, the stark black and white landscape of provides a fine palette for the burst of colour created by a large phytoplankton bloom, spotted by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra  satellite on August 7, 2010.

The bloom blends shades of milky blue, turquoise, and green, created by different species of phytoplankton growing in the cold, nutrient-rich waters. Likely shaped by the East Greenland Current, the bloom extends along the southeast coast of Greenland.

The full length of the bloom is visible in the large image (0.7MB, new window), which shows a broader area.

The phytoplankton bloom is not the only source of colour in the scene. The brilliant white of the ice sheet fades to grey in places along the shore where old ice is exposed. Tinted faintly brown like the craggy brown rocks that channel them, glaciers seep from the ice sheet into fjords, rivers of ice draining the great ice sheet. The glaciers give way to green-blue water, milky with the fine sediment created as the ice grinds over rock.

These waters and the deep black-blue waters of the Atlantic Ocean are dotted with icebergs. No more than tiny white specks at this scale, the icebergs resemble tiny grains of salt floating on the water’s surface.

NASA images courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC; and Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team and the United States Geological Survey. Text adapted from information issued by Michon Scott and Holli Riebeek.

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