About ice islands, by Preben Gudmandsen (National Space Institute

of Denmark)

  • Ile de glace PII2012A1d-2km2

I believe that what we observe presently is a new area but who knows about the past when we did not have satellites to assist us?

When I first observed the calving of the Petermann Glacier some times in the 90-s it was based on satellite images of the Kennedy Channel that had three floes that were different from all the other floes coming from the Lincoln Sea. It was based on SAR scenes recorded by chance by the European satellite ERS-1 some weeks after its launch in 1991. Fortunately, other observations taken two and four weeks before showed that the floes came from Petermann Glacier. Based on previous observations from aircraft I suggested that calving would take place every 9 or 10 years.

The next calving took place in 2000 so I was right, but since then climate has changed so we had the next major calving in 2008 although smaller than before and what we have seen recently. As you know we had other calvings from Petermann Glacier in 2010 and now also in 2012. And very large ones coming from further up the floating tongue of the glacier which means that the thickness and therefore the draft has increased (the main melting process of the glacier tongue takes place from the underlying water).

This means that we have more ice islands than before and due to the increased draft the probability of grounding increases. Yes, it is a special situation that we experience.

ERS-1 scenes of the Lincoln Sea showed that in 1991 there were also an ice island with origin Steensby Glacier or Ryder Glacier but I have only one observation. What we see now is that this happens again and more frequent than before.

In all you observe a unique situation with the many fragments of calvings from Greenland distributed by chance along the coast of Baffin Island sounding the (unknovn) coastal bathymetry. Not knowing the exact draft of the bergs it is of minor interest. Several of them have been grounded on the way and later left the place to ground on another ground further south.

Yes, you experience something very interesting.