The clouds have subsided again a bit, so I've updated the animation showing Lockerby Ice Island's travels:
It was stuck for a while, but came loose between Day 237 and 241. Patrick Lockerby says in his latest piece on the ice island:
If, as I suspect, it is becoming more grounded with each day after the full moon / spring tide then its next surge forward may be expected around new moon September 08 or full moon September 23 2010 - unless wedged in place by packed ice before then.
Also the island is wedge shaped so I'd expect it to align with the current when it gets in the main channel.
Posted by: me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk- | August 30, 2010 at 05:09
Will the iceberg break up as it heads into the strait? We have no precedent for something this big in this area. I do notice some new snow at high elevation around the Petermann on day 241 the melt season is very close to over for the glacier.
Posted by: Glacierchange.wordpress.com | August 30, 2010 at 15:53
"Also the island is wedge shaped so I'd expect it to align with the current when it gets in the main channel."
That is exactly what is happening.
Patrick is better at this stuff than me, for sure, but I think he is wrong abou this. The island looks to me to have moved forward another 5 kms in the last 24 hours, and rotated counterclockwise a bit (as the nose is pushed to the right by ice moving down Nares). I don't see any sign that it is grounded at this stage (although it may yet run aground on the left headland if it rotates too much).
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2010242/crefl2_143.A2010242115000-2010242115500.250m.jpg
Personally, I think its free to run, but it will probably go aground further down Nares Strait, on Hans (or possibly Franklin) Island. If it does, it may slew around and block the whole strait. But if it doesn't its heading for open sea.
Posted by: FrankD | August 30, 2010 at 18:10
I agree that is doubtful it is substantially grounded. Recall that at the ice front the sea ice was less than 70 m thick and even at the rear of ice it is likely less than 200 m thick. This is not very deep for such a large fjord. As noted by Muenchow et al 2010 The 1100m deep fjord is separated from neighbouring Hall Basin by a sill between 350m and 450m deep.
Posted by: Glacierchange.wordpress.com | August 30, 2010 at 22:34
I'm enjoying the whole "is it-isn't it" thing: today it turned really sharply, making me think it might be a bit stuck on the south side. Fairly sure it also moved forward a k or two though, so probably not seriously stuck, if at all. But the sharp change in direction did enhance its chances of ploughing into the headland on the south side of the fjord rather than travelling down the strait.
With 2008 extent beginning to look out of reach, the fate of Petermann Ice Island is the most interesting thing going on, for me. Gotta get me some popcorn....
Posted by: FrankD | August 31, 2010 at 11:02
This story made Science Daily today:
http://www.sciencedaily.com/releases/2010/09/100903072655.htm
Kind of fun.
Posted by: Kevin McKinney | September 03, 2010 at 18:24
Here is the latest ASAR microwave image from the Danish Centre for Ocean and Ice:
http://ocean.dmi.dk/arctic/images/MODIS/Kennedy/201009030044.ASAR.jpg
Petermann Ice Island has begun the long, graceful turn to the South into the main flow of Nares Strait. The nose in now in the flow, and is creating significant downstream eddies in the sea ice. It appears the ice island has struck the south entrance of the fjord amidships, and this seams to be assisting its rotation into Nares strait. There is no sign yet of any fracture due to the turning torque, and with this being old, fresh ice the island may arrive in the Strait mostly intact.
Posted by: Artful Dodger | September 03, 2010 at 22:42
Artful Dodger as you can see from the image it's currently jammed against Joe Island, it'll be interesting to see how it breaks free.
Posted by: me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk- | September 04, 2010 at 02:57
Today is the New Moon, and Petermann Ice Island 2010 is on the move again with the Spring tide. Compare these two images: (2 days apart)
http://ocean.dmi.dk/arctic/images/MODIS/Kennedy/201009061557.ASAR.jpg
http://ocean.dmi.dk/arctic/images/MODIS/Kennedy/201009071707.ASAR.jpg
Posted by: Artful Dodger | September 08, 2010 at 13:58