Large iceberg breaks off Petermann Glacier

By HansPeter Roesli (EUMETSAT)

As reported on NASA Earth Observatory, on 5 August 2010, an enormous chunk of ice, roughly 250 km² in size, broke off the Petermann Glacier along the northwestern coast of Greenland. The Canadian Ice Service detected the remote event within hours in near-real-time data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. The Petermann Glacier lost about one quarter of its 70km long floating ice shelf.

Like other instruments on various polar-orbiting satellites (e.g. MODIS or ASAR) the AVHRR imaging radiometer on Metop-A also observed this major calving of the Petermann Glacier in Greenland in summer 2010. All images shown here are Natural Colour RGBs from the AVHRR instrument on Metop-A, where water clouds appear in white-pink, ice clouds and snow in bright cyan and ice (sea ice or glaciers) in darker cyan.

The Petermann Glacier is a large glacier located in a fjord that opens into the Nares Strait between Ellesmere Island and north-western Greenland (Figure 1).

During recent years the glacier has advanced towards the Nares Strait forming a floating tongue of ice 70km long and 15km wide. As mentioned above, on 5 August 2010 at the end of the glacier a large piece broke off with a length of 20km (Figures 2 and 3).

Thanks to the excellent coverage of the area by Metop's AVHRR instrument and several spells of little or no clouds it has been possible to document reasonably well the evolution of the iceberg also after its break-off up to 22 September 2010. The animation (Figure 4) shows the whole sequence in slow motion.

Orange arrows at the beginning point to the zone of break-off and from 11 September onward help to follow the iceberg down the Nares Strait. Note also a fast-moving elliptical iceberg (white arrows on Figure 5) that passes to the west of the iceberg of interest (red arrows) at 50km/day.

In summary, up to 29 August the iceberg remains inside the fjord swiveling to the left and right and only moving slowly towards the outlet. From 29 August the iceberg is trundling at the mouth, losing some bits between 5 and 11 September (no observation between 6 and 10 September due to persistent cloud). By 16–17 September the remnant of the large iceberg enters the Nares Strait and starts to accelerate southwestwards. On 22 September the iceberg leaves the observation window at a speed of 30km/day.

Additional content

Terra MODIS image, 5 Aug 2010 (source: NASA Earth Observatory)
Terra Advanced Land Imager image, 16 Aug 2010 (source: NASA Earth Observatory)