POAC 09 - Bedford Institute of Oceanography
POAC 09 - Bedford Institute of Oceanography
POAC 09 - Bedford Institute of Oceanography
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2001. The Petermann Glacier is located in northwest Greenland, and seaward <strong>of</strong> the grounding<br />
line, it consists <strong>of</strong> a floating glacier tongue about 70 km long and 15.5 km wide (Higgins, 1991).<br />
Another major calving event occurred in the summer <strong>of</strong> 2008, mostly in the form <strong>of</strong> a single ice<br />
island over 20 km 2 in area. This paper describes its drift southward, by tracking it using satellite<br />
imagery (Envisat and MODIS), and two satellite-tracked ice beacons deployed on the ice island.<br />
DRIFT FROM THE PETERMANN GLACIER TO JONES SOUND<br />
A MODIS image from 18 July 2008 (Fig. 1) shows the large ice island (A) which calved from the<br />
west side <strong>of</strong> the glacier by 13 July, and a smaller ice island (B) which calved from the east side<br />
by 16 July. The large ice island calved along a fracture line E similar to the position <strong>of</strong> the front<br />
in 2000. This fracture line may have formed due to basal melting observed along one <strong>of</strong> several<br />
channels near the grounding line <strong>of</strong> the glacier (Rignot and Steffen, 2008).<br />
A<br />
C<br />
Fig. 1. MODIS Image from 18 July 2008 (1920Z) showing two ice islands (A and B) calved from<br />
the Petermann Glacier (C), and sea ice to the north in Nares Strait (D). The bottoms <strong>of</strong> the arrows<br />
indicate the origin <strong>of</strong> the ice islands.<br />
The large ice island was tracked using Envisat and MODIS imagery between 13 July and 15<br />
September 2008, when two ice beacons were deployed on the ice island northeast <strong>of</strong> Jones<br />
Sound. The complete track <strong>of</strong> the ice island from the Petermann Glacier south to Lancaster Sound<br />
between 13 July and 10 February 20<strong>09</strong> is shown in Fig. 2.<br />
Although the ice island calved in mid-July, the ice island did not enter Nares Strait for 3 weeks<br />
until a major wind event cleared sea ice from the mouth <strong>of</strong> the Petermann Fjord. The mean sea<br />
level pressure pattern between 01 August and 06 August 2008 using NCEP/NCAR reanalysis<br />
data (Kalnay et al., 1996) shows that strong winds blew northward through Nares Strait (Fig. 3).<br />
A passive microwave (AMSR-E) image for July 31 shows high concentrations <strong>of</strong> sea ice both<br />
B<br />
E<br />
D
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