Petermann calves again

Petermann Glacier has calved another large ice island, about half the size
of the calving of two years ago, which amounts to about two Manhattans.

This is what it looks like:

This second big calving (spotted this time by Arcticicelost80) is another spectacular event on Greenland this year, following retreats of the Jakobshavn Glacier and lowest reflectivity of the Greenland ice sheet on record (see blog post), leading to unprecedented flooding in the southwest of Greenland. This calving was expected to happen, as the rift in the glacier has been there for years (see this thorough explanation by glacier expert Mauri Pelto).

From the Icy Seas blog:

This morning Petermann Glacier lost another ice island of a size comparable to what it lost in 2010:

The break-off point has been visible for at least 8 years in MODIS imagery propagating at speeds of 1 km/year towards Nares Strait. The fracture also extended further across the floating ice sheet from the northern towards its southern side.

This event is still evolving, Trudy Wohleben of the Canadian Ice Service noticed it first (as in 2010) after reviewing MODIS imagery. Several people in several countries are monitoring and assessing the situation, but a first estimate of its size is 200 km^2 (3 Manhattans), I will revise this figure as soon as I got my hands on the raw data.

Read more here.

Two years ago Patrick Lockerby was the first to tell the world about the big calving that occurred at Petermann Glacier. The Arctic Sea Ice blog followed suit shortly afterwards. The whole event garnered a lot of attention, popularizing the island of Manhattan as an area measurement tool (square metre, square kilometre, Manhattan ;-) ). This second big calving in as many years doesn't come as a surprise, as attested by this article on the New York Times blog from August last year:

Thanks to satellites and other instruments, researchers do know what is happening to ocean and air temperatures in northwest Greenland. They have been warming briskly of late, as global-warming theory predicted decades ago that they would for the whole Arctic.

Dr. Box finds a drastic increase in sea-surface temperatures in the region, and a sharp decline in sea ice. Scientists suspect that warmer water is circulating under Greenland’s floating ice shelves and causing them to weaken. But given the dearth of measurements from beneath Petermann, they do not have hard proof that is what happened in this case.

The breakup of the Petermann ice shelf fits into a broader picture. Many lines of evidence suggest that melting and breakup of Greenland ice, a phenomenon once concentrated on the southern end of that island, has spread to the colder northwest corner. As I reported last year, many scientists are worried about the overall fate of the Greenland ice sheet, especially the prospect that its melting could raise global sea levels substantially.

(...)

Dr. Box said another chunk of the Petermann Glacier, this one about twice the size of Manhattan, is now on the verge of breaking loose.

Dr. Box was right. Some more info on the blog of the Byrd Polar Research Center blog last year:

In response to the question: How abnormal is this event? Jason notes: "The August 2010 ice calving at Petermann is the largest in the observational record for Greenland" Falkner et al. (2011) scoured the observations and found no evidence of an event this large in scattered observations since 1876. Johannessen et al. (2011) identified the next largest observed Petermann calving event ocurring in 1991, being 58% as large as the 2010 event.

Another image can be added to these two posted in the same BPRC blog post (check out the little Eiffel towers on the left that give an idea about this mamma's magnitude):

When it comes to those "dearth of measurements" mentioned in the article, Andreas Münchow, a sea-going physical oceanographer from the University of Delaware, is supposed to go to Nares Strait (here to be precise) on the Canadian Coast Guard Ship Henry Larsen at the beginning of August to retrieve instruments that have recorded ocean current, temperature, salinity, and ice thickness data at better than hourly intervals from 2009 through 2012. As Dr. Münchow says in a comment following the blog post I alluded to at the top:

I am crunching numbers … this is a very worrisome event that will make our lives to get a ship recover our instrumentation more challenging and risky. I hope that this ice island will stay inside the fjord until we have safely entered and exited Nares Strait the first 2-3 weeks in August.

Interestingly enough the remnants from the previous calving still linger, and are closely followed by Environment Canada:

Here's a video of one of those chunks, back in June 2011:

 

And another video as seen from an airplane in August 2011:

 

Comments

[dorlomin]

Hmmmm they have not accused it of causing cancer, are we sure this is the Daily Mail?

[idunno]

For the benefit of any Daily Mail hacks using this site to research new material; okay, I may have accused the sea ice area graphs of having a fat arse, but there is no way you will be able to find a pap shot of it wearing a bikini.

[FrankD]

Well if the Daily Fail have started reporting from the Archtic, then I'm looking forward to seeing whether the next Sun headline of "Phew! What a scorcher!" actually refers to the weather somewhere...

[Werther]

For what its worth under cloud cover, I compared the Humboldt calving front to a 9 July 2011 pic and missed a total of 15 km2.
When a good pic gets through, I'll try to verify.
With this in mind, I think the Humboldt is playing along with its brothers in arms...

[Account Deleted]

http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=78648

"On July 21, 2012, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite captured this image of the iceberg’s continuing journey. This image has been rotated and north is toward the right. This detailed image reveals that the iceberg covers an area of about 32.3 square kilometers (12.5 square miles)."

[me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-]

Today's Modis shows the ice island making steady progress down the fjord. Despite the clouds you can see that the first break has occurred.

http://i302.photobucket.com/albums/nn107/Sprintstar400/Petermann2.jpg

[me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-]

Really clear Modis image of the Petermann today.

Phil.

http://i302.photobucket.com/albums/nn107/Sprintstar400/Petermann3.jpg

[Bernard Vatant]

Back to Petermann since after all it is the original topic :)
Today's view is clear from clouds. http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2012212.terra.250m
The ice island has drifted more than 20km since the calving event, that is more than 1km/day. At the same speed it will take between one and two more weeks to enter Nares main stream.

[Espen Olsen]

Petermann Glacier:

We may have a new calving potential looking from this 250m Modis orbit swath image, there is a marking across I never noticed before it is about 5 - 10 km behind the new edge:

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2012212182500-2012212183000.250m.jpg

[Account Deleted]

I think that is a cloud shadow Espen

[Artful Dodger]

No clouds in the area Philip, that feature is on the ice. Check the Aqua Bands 3-6-7 image:

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2012212.terra.367.250m

[Espen Olsen]

Artful Dodger,

Thanks, because I did not any clouds neither, that made me suspicious!

[Mike Constable]

The dark streak is similar to ones that can sometimes be seen on the Ross ice-shelf in the southern hemisphere. I noticed some of them years ago and one is associated with a new berg which has been threatening to break away for a long time.

[Seke Rob]

That 1km/day is an interesting fact to consider. Is it wind, is it ater in substantial amounts coming off GIS, is it some water turbulence from the Nares channel... water pushed in one side and leaving the other, of course, could be the sum of all 3.

[Neven]

I also thought it was a shadow from a wisp of cloud. I'm not seeing anything on today's near real-time satellite image, but if something does show up later today on the Arctic Mosaic I'll put up a short blog post.

[Russell McKane]

I looked a them earlier today and I noticed that there where similar wisps to the left (Humble side) on the non glacial snow surface. I suspect they are wind trails possibly surface ice/snow leaving a shaddow.
PS High folk, still following religiously but Boy I miss my Polar eye website with the Satalite crash so have been unable to work further on my visual prediction modelling.

[Daniel Bailey]

Neven, am in agreement with Lodger. Using his referenced imagery, clouds on ice lighten the tone of the false-color red for the ice. The feature in question is darker in tone, similar in tonal coloration to the ice striations running in the bedding of the ice tongue parallel to the direction of the flow of the ice. Since the feature runs perpendicular to the direction of flow, it is reasonable to conclude it to be an area of potential calving.

[Daniel Bailey]

Alternatively, they could be artifacts from the stitching process used to merge the satellite swaths together. Something to watch, in any event.

[dingojoe]

I think there may be a calving disintegration event goint on on the East side of Greenland right now.

If you look at the Modis subset that includes 79 North and Zachariae and then move from those two Southwest along the inland channel you will reach a point where the termini of two glaciers meet--Storstrommen from the North and L. Bistrup Brae from the South. The meeting point is just SSW of an oval Island surrounded by Storstrommen. Just to the SE of the termini is Borgfjorden.

A week ago Borgfjorden was mostly open water, but now it's filled up with a stream of frothy looking ice coming from the termini. I think it's primarily a portion of the terminus of Storstrommen that is disintegrating as it too has a disrupted look to it's surface.

Here's how it looked on 7-30

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r02c03.2012212.terra.250m

Here's how the termini looked two years ago

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r02c03.2010235.terra.250m

[Espen Olsen]

DingoJoe,

Yes there is definitely a lot on the move in that area, and it will be interesting to see how it all looks like in September.
Did you notice that big piece of ice just south of Shannon Island, how it blowed into to smaller pieces in the last 24 hours?

[Peter Ellis]

Daniel, Lodger: I think it's a shadow. The cloud itself is above the cliffs on the western side of the glacier - you can just see it against the snow. The cloud's quite high and the sun angle is low, so the shadow is well displaced from the cloud.

[Neven]

And abracadabra, gone again on today's satellite image. :-)

[Bernard Vatant]

Comparing images of MODIS between yesterday and today might give some clues about what is going on between the calving front and the ice island.

July 30:

July 31:

The ice island itself has pivoted clockwise about 30°, sort of "rolling" on the right bank of the fjord.
Meanwhile the configuration of icebergs behind the island has been completely messed up. But I would guess that the long narrow one indicated by the red spot, about 3 km long, is the same in the two images. Looks like there is a strong anti-clockwise current there moving this stuff around.

[Artful Dodger]

Here is the 5 minute swath data used for the Day 212 (July 30) image:
http://lance-modis.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2012212164500-2012212165000.500m.jpg

I'm confident the striations on the July 30 Mosaic image are not clouds, since they span the entire width of the fjord.
However, they may well be processing artifacts. It's good that people are watching though.

Cheers,
Lodger

[Seke Rob]

Bernard, that's an interesting analysis and would have been my best guess of how the entry/exit current ["turbulence" lacking a better word at writing] would be. Thx

[fredt34]

While Neven gently sleeps... Dr Muenchow has posted the first two pictures of the Peterman Ice Island 2012, taken from an helicopter: http://icyseas.org/2012/08/17/nares-strait-2012-first-petermann-ice-island-photos/

Amazing...

[Neven]

I'm awake, I'm awake! ;-)

I think I'll repost this.

[Twemoran]

PII2012 Breakup

Yesterday, as noted by Dr Muenchow at his blog

http://icyseas.org/2012/09/02/petermann-ice-island-2012-breaking-up/

PII2012 broke up on the sill in Kane Basin. Dr M posts here, but if you haven't been to his site you've been missing some interesting stuff! He recently retrieved data that includes the bottom profile of PII2010B amongst other interesting tidbits.

Terry

[Espen Olsen]

This is a re post:

Kangertittivaq / Scoresbysund East Greenland:

Calving activities: Døde (Death) Bræ is calving big way with her bigger brother Vestfjord Gletscher and further inside the fjord system Daugaard-Jensen Gletscher is on move as well.

Further up north Tobias is spewing ice and Newman Bugt calved at piece relatively in size as big as Pertmann II.

[Seke Rob]

Petrmann II aka Petermann II, Stanley presumes twice. The grand incontinence of the Greenland outlets.

[Espen Olsen]

Yes it was a "typo" Petermann II!

[Espen Olsen]

Humboldt Glacier North Greenland,

Heavy calving action is seen in front of Humboldt the neighbor to Petermann. Updates follows:
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012250113500-2012250114000.250m.jpg

[Espen Olsen]

Petermann Glacier,

If I am not completely wrong, but I think we are seeing some trimming (slice calving) of the edge in both southern and northern part.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012255115500-2012255120000.250m.jpg

[Espen]

Petermann Glacier action:

There is definitely something on the move at the front of Petermann, if you compare these 2 modis in 2 different tabs, you will a difference in just +/- 24 hours, I would like to have some comments from some who cares? Thanks!

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012256141500-2012256142000.250m.jpg

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012256141500-2012256142000.250m.jpg

[Twemoran]

Espen

I care, but I think the links are to the same image. A little description of what you're looking at might help (old eyes)

Terry

[Espen]

Terry;

I dont know what went wrong, sorry, here is an image from 254: Have a look at the whole front of the glacier. Espen

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2012254.aqua.250m

[Twemoran]

Espen

Those huge graphic files slowed my system to a crawl. I'm going to reboot to speed things up.

If subset's are adequate to see what you're referencing I'd prefer them. Is it the calving off the Humboldt that has caught your eye, or the movement of the ice to the south shore in Petermann Fjord - or something else?

Humboldt is producing large amounts of ice from somewhere, without noticeably retreating, (possibly the front is being undercut?) The other possibility is that FYI in the crook of the horn is being flushed out, although there appears to be too much ice for this.

Still not clear that this is what you're referring to though.

Be back when I've rebooted & cleared out some files.

Terry

[Espen]

Terry,

Yes I have noticed the activity at Humboldt, and it almost the same happening at Petermann, those ice slices can be 60 - 70 thick and when they turn around in the sea they appear much bigger from a satellite eye.
But I am pretty confident there were some noticeable ice loss at Petermann over the last couple of days, some at the south side is gone and part of north side is one.
Did you notice the calving at Newmann Bugt a week ago, size wise (relatively) as big as Petermann in July, it is the unnamed Glacier in Newman Bugt next door to the north from Petermann Fjord.

[Twemoran]

Espen

Hadn't noticed anything at Newman, but being bracketed by Petermann and Steensby certainly leaves it in a danger zone.

I've wondered about whether the "tributaries" feeding into Petermann from the north, that used to merge into the glacier, might now disrupt it's front.

Terry

[Warzypants]

Had a quick look after Espen's heads up and I'd have to agree that Petermann looks a little changed at either side.

[skywatcher]

Don't think Petermann itself has changed much (comparing the 250m images of day 250 and 256, the ice front remains about stationary and doesn't visibly calve back (though there's a fair bit of room at a 250m resolution!) but in betweentimes, some sea ice from Nares wandered in towards Petermann up to day 254. It's an interesting coincidence that the extra debris appears as some sea ice, which had been gradually entering the fjord over the preceding few days, gets blown to one side. It's plausible that the bright white material next to the ice front is little more than a mash of the sea ice, but also plausible that the same conditions that brought and moved sea ice into the fjord, triggered some small calving.

[Espen Olsen]

Newmann Bugt,

As you can see on this modis 250m from August 30 2012, a piece went of at the Newman Bugt Glacier aprox. +/- 2 km2, or relatively the same size as Petermann II.

Skywatcher,

I agree not much have changed at Petermann, but I am pretty sure something changed.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012243131000-2012243131500.250m.jpg

[Espen Olsen]

If am not wrong, I believe it is the first year we watch all 3 glaciers calved Petermann in the same season (2012 - 2010) Steensby (2012 - ?) and Newman ( 2012 - ?)
And Steensby should not calve at all according to this report from Frank Ahnert 1962, he got it all wrong in the first paragraph: http://www.igsoc.org:8080/journal/4/35/igs_journal_vol04_issue035_pg537-545.pdf

[Andreas Muenchow]

Nice find of a paper, Espen. I had not seen it, but always love to read what people were thinking 40-50 or 100-150 years ago as it often puts the present into a larger perspective. If only the day had more hours or one could get by with less sleep ... to read more or to apply new edge detection codes to quantify motion and change while also account for mountain shadows. Devils and details.

[Espen Olsen]

Andreas,

Yes I found it a bit funny when I read it, but many of those old reports including the Coppinger report of Petermann you supplied me,are almost like being there with horses dogs and polar bears.

[Isabelle]

This video has all the drama, thanks for sharing