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Author Topic: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada  (Read 17634 times)

Espen

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Just studying the recent Modis 250M from top of Ellesmere Island, I am surprised not to see any shades from Ice Shelf, I assume there is level difference between the Sea Ice and the Ice Shelf.
What are the latest report about the situation, is it still alive?

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2013103.terra.250m

http://www.ec.gc.ca/glaces-ice/?lang=En&n=056B4D49-1

Click on image to enlarge:

« Last Edit: July 17, 2013, 07:02:51 PM by Espen »
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Neven

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #1 on: April 14, 2013, 10:26:35 AM »
For folks who want some quick background info: You do it to your shelf.
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Espen

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #2 on: April 25, 2013, 05:07:46 PM »
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Jim Williams

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #3 on: April 25, 2013, 05:33:16 PM »
A massive crack is developing all along the north of CAA:

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2013115114500-2013115115000.2km.jpg

Yesterday was impressive and I'm waiting for today.  Wouldn't you know that this is usually one of the last areas to get filled in during the day....

Espen

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #4 on: April 25, 2013, 05:43:46 PM »
« Last Edit: April 25, 2013, 06:00:20 PM by Espen »
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Jim Williams

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Espen

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #6 on: April 25, 2013, 06:03:41 PM »
Jim;

The cracks north of Nares are much bigger and more developed today than yesterday.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2013115114500-2013115115000.250m.jpg
« Last Edit: April 25, 2013, 06:12:02 PM by Espen »
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Jim Williams

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #7 on: April 25, 2013, 06:23:44 PM »
So the question is, is it warm enough yet that the cracks don't immediately freeze over?

How I wish we had some decent data from under the ice.....

All the hints are for a fast and wild thaw, but there's nothing that can be called real data saying so.

Espen

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #8 on: April 25, 2013, 06:27:17 PM »
Jim;

It is still very cold: Alert - 24C
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Peter Ellis

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #9 on: April 25, 2013, 11:17:18 PM »
Here are the overview pictures back to 2009.  In all honesty, if you gave them to me in a random order, I could not tell which was which, or indicate which was worse than any other.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2009114.terra.4km
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2010114.terra.4km
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2011114.terra.4km
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2012114.terra.4km
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2013114.terra.4km

Yes, this year has a shore lead all the way along the north of Ellesmere island - but by this date 2010 had substantial open water in the Canadian Archipelago, 2011 has more open/shattered ice off the Chukchi coast, and 2012 had more obvious cracks throughout the Beaufort.  The leads from this year's event have had a good couple of months of intense cold to re-freeze and grow more ice.  I think we need to be wary of prophesying doom and gloom - every time we do and it doesn't happen, it makes the real changes that much easier to dismiss.

Neven

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #10 on: April 25, 2013, 11:53:59 PM »
Wow, will you look at 2010! I started the blog in June that year, but could only vaguely remember how well advanced the break-up was in the CAA, with no ice arches in Nares.

That just goes to show that most of the details in the Arctic have happened before, especially around this time.
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Artful Dodger

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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #11 on: April 26, 2013, 06:40:49 AM »
A massive crack is developing all along the north of CAA:
Hi Espen,

Yes, April 25 is the Full Moon. This is to be expected on the Spring Tide. The real issue to watch for is horizontal movement of the pack ice. If it starts heading South toward the Beaufort sea at a steady pace, it will all melt by the end of Summer.

Then it's game over, MYI.
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Re: Ward Hunt Ice Shelf / Ellesmere Island
« Reply #12 on: April 27, 2013, 07:55:39 AM »
There are two WHOI ice tethered buoys just north of Ellesmere Island # 63 and #48. They show current drift rates that are slow right now. They are in good position to watch the spring proceed.       http://www.whoi.edu/page.do?pid=20781

Espen

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #13 on: July 17, 2013, 12:37:22 PM »
Just did some studies of the remaining ice shelf locations on Ellesmere Island.

The blue areas indicate where I found traces / remains of the Ice Shelves.

Click on image to enlarge:
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TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #14 on: July 21, 2013, 06:41:36 PM »
I think both halves of Ward-Hunt have been vulnerable since the ice link joining them broke away in 2011. In September & August I check MODIS for clear days in the area just to see if everything is still in place. Back in 2011 I reported the missing link between the two at the ASIB 2 days before it was confirmed by the University of Guelph, so it's still possible to spot features through the clouds before they are announced.


The studies of driftwood dates at Ellesmere are the easiest way to shut deniers up when they insist that this is all part of some regular cycle. England's findings are easy to google and read & offer proof positive that we need to go back to the HTO to find conditions similar to what we're now experiencing.


Terry

Espen

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #15 on: July 21, 2013, 06:50:50 PM »
"Back in 2011 I reported the missing link between the two at the ASIB"


Terry you got it wrong, you announced it and the laurels went elsewhere!
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sidd

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #16 on: December 17, 2013, 12:14:45 AM »
Ward Hunt measurement from 1959

http://www.cbc.ca/news/canada/north/1959-message-in-a-bottle-a-clue-to-glacier-melt-1.2465597

http://thechronicleherald.ca/canada/1173466-54-year-old-message-in-bottle-helps-chronicle-death-of-glacier?from=most_read&most_read=1173466

Looking at their obituaries (both at Journal of Glaciology, other versions elsewhere), I feel certain that Walker knew Mercer and had informed prescience that the glacier would retreat rather than advance.

sidd

TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #17 on: August 20, 2016, 12:50:24 AM »
This might be a good time to re-visit Ward Hunt.


The wind is crazy, spring tide is in 2 days, and I've been waiting for action since the 'link' broke back in 2011. If GAC2 drifts a little further east Ward Hunt certainly couldn't be faulted for breaking it's last hold on land, or at least shedding a portion of what is left of it's once massive shelf.


Terry




TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #19 on: August 22, 2016, 01:19:45 AM »
Wow, Terry, I had no idea there was still a piece of it sitting there.  How on earth is it holding on?  It was still there on August 11:

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2016-08-11&v=-611624.4394552563,-782728.5972047597,-218408.43945525633,-593544.5972047597


Still seems to be holding on Aug. 20, but the next few days could be telling. Last time Neven addressed it was back in 2011 after the link between the two sides failed. I don't think things have changed much since then.
http://neven1.typepad.com/blog/2011/09/you-do-it-to-your-shelf-.html


Terry

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #20 on: August 22, 2016, 01:50:02 AM »
Thanks, Terry.  A nice discussion.  Unfortunately, many links now broken.  Is there evidence on how old the Ward Hunt remnant is?

TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #21 on: August 22, 2016, 05:31:10 AM »
Thanks, Terry.  A nice discussion.  Unfortunately, many links now broken.  Is there evidence on how old the Ward Hunt remnant is?
Equally unfortunate that most of my bookmarked links are also no longer viable. IIRC John English has done the heavy lifting re. dating of the old Ellesmere Shelf and ascertained that drift wood behind the current remnants was captured between 9.2 & 5.5 k yr BP. Many of his logs were found upstream in Disraeli Ford, which only opened again in 2002.


The first link is to one of his papers.
http://onlinelibrary.wiley.com/doi/10.1029/2008GL034470/full


The second has great photos (some animated) re. the calving in 2008.
http://www.trentu.ca/iceshelf/wardhunt.html


Somehow I'm drawn to the loss of these ancient shelves that won't be replaced for many generations (if ever).


Terry

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #22 on: August 23, 2016, 06:37:34 AM »
Thanks, Terry!

We know those ice shelves aren't coming back for eons -- it does make one feel a bit sad.

nukefix

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #23 on: August 23, 2016, 11:46:57 AM »
Here's the situation in the west as seen by S-1A 22.8.2016 in dual-pol IW (20m pixel-size UTM zone 16). Red arrows from left indicate:

- Serson ice shelf remnant (still there)
- Petersen ice shelf remnant (practically gone)
- Milne ice shelf remnant (still going strong)

TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #24 on: August 23, 2016, 07:07:29 PM »
NF


Wonderful graphic, but I think you're a little west? of our subject.


https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels,Reference_Features(hidden),Coastlines&t=2016-08-16&v=-695356.2946157213,-756959.4090445098,-227388.29461572133,-522975.40904450975


is from the 16th. Ward Hunt extends east across Disraeli Fjord rather than being limited to the larger western portion that is labeled on Worldview.


Terry

nukefix

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #25 on: August 24, 2016, 10:40:06 AM »
Here's a S-1A view of Milne and Ward Hunt ice shelves on 23.3.2016, downsampled to 30m resolution in UTM17:

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #26 on: August 24, 2016, 02:28:04 PM »
Here's a S-1A view of Milne and Ward Hunt ice shelves on 23.3.2016, downsampled to 30m resolution in UTM17:

Are the shelves the areas of bright white ice?

nukefix

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #27 on: August 24, 2016, 03:27:47 PM »
Here's a S-1A view of Milne and Ward Hunt ice shelves on 23.3.2016, downsampled to 30m resolution in UTM17:

Are the shelves the areas of bright white ice?
Good question, I added some arrows to make it clearer. The old shelf ice appears striated, while some of the bright smooth ice is small ice caps.

TerryM

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #28 on: August 24, 2016, 08:13:32 PM »
NF


Fabulous Photos !!!


I believe I can make out the ridge patterns that distinguish both portions of the shelf from the very recent fast ice at the end of Disraeli Ford.


At some point huge ice islands will calf, but probably not this year.


Thanks again for the image!
Terry

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #29 on: August 25, 2016, 02:40:07 AM »
Here's a S-1A view of Milne and Ward Hunt ice shelves on 23.3.2016, downsampled to 30m resolution in UTM17:

Are the shelves the areas of bright white ice?
Good question, I added some arrows to make it clearer. The old shelf ice appears striated, while some of the bright smooth ice is small ice caps.

Thank you.

sidd

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #30 on: September 23, 2017, 10:54:03 PM »
Charming paper about an arctic epishelf lake on Ellesmere by Hamilton et al.
Open access. Read all about it.

https://doi.org/10.5194/tc-11-2189-2017

sidd

Espen

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #31 on: September 23, 2017, 11:05:46 PM »
Not sure but I could imagine Hunt Fjord, Northern Greenland being an epishelf lake?
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sidd

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #32 on: September 24, 2017, 12:01:57 AM »
yes, i think more epishelf lakes will be recognized as melt proceeds. I hope more of them get instrumented like this one.

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #33 on: August 03, 2020, 04:55:03 AM »
Cross-post:

This seems important.

Maybe if we are lucky, Ossifrage will get some time to check in and let us know what he is seeing.

The ice north of Greenland and the CAA is really getting hammered this year. Historically, it was assumed that the ice north of Greenland and the CAA would be the last to go. This year, it looks possible there could be an ice free shipping route all the way from the Fram, north of Greenland and the CAA, into the Beaufort.

Does anyone have the CAB detaching from North America on their 2020 bingo card?




oren

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #34 on: August 03, 2020, 04:56:17 AM »
Cross-post:

It's nice to see several people are taking note of what's going above Greenland/the Lincoln Sea. This entire region just continues to surprise and I wish I understood more of the dynamics which facilitated such a vast separation plus an ever-widening crack.
This is today.  There is a lot going on.  Interesting swirls in the open areas extending north from Greenland.  Then there's the interesting feature in the lower right, and the subsequent waves propagating northward.  After seeing this gif from blumenkraft.
https://forum.arctic-sea-ice.net/index.php/topic,2649.msg277039.html#msg277039
I get the feeling the "plunger" action of the tide moving north through the Nares sends a wave that gets trapped along the coast due to coriolis. It's then forced upwards due to bathymetry, creating the swirl, with some of the wave reflect back, but much of it continuing poleward.
There is a lot of "sloshing" in the Lincoln Sea area.
Contrast boosted.  Click to run.

That's amazing and even more so  that the huge chunks of land fast ice have broken off from gis.

Historically those are between 6-15M thick.

Sometimes upwards of 30M thick.

They will likely never reform because the ice that replaces it will  be to thin to withstand  breaking off for many seasons.

The most immediate impact I would think besides possibly Coastal erosion will be the crack in the future along the land in the southern basin will be wide enough that warmer water will probably form there and help eat away at the thickest ice every summer.


Although this summer has seen more southerly winds coming out of the CAA in Greenland then I can remember since at least 2007

Your comment made me look a little closer friv. That was actually a floating ice tongue of the Milne? glacier. It was more like 100m thick (in the 80s) and was the second largest ice Shelf in the attic. So that’s actually a pretty substantial iceberg.

https://en.wikipedia.org/wiki/Milne_Ice_Shelf

https://wirl.carleton.ca/research/ice/ice-shelves/milne-ice-shelf/

https://www.rcinet.ca/en/2013/08/09/eye-on-the-arctic-understanding-the-milne-ice-shelf/

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JF002074

Edit the shelf was thinner but still pretty thick and held back a epishelf lake. Which I had to read up on. Also the scientists camp and instruments were destroyed but luckily they were not there.

NotaDenier

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #35 on: August 03, 2020, 01:07:40 PM »
The Milne glacier and its floating tongue.
Cross post. https://forum.arctic-sea-ice.net/index.php/topic,3237.msg279132.html#msg279132
« Last Edit: August 03, 2020, 07:06:03 PM by NotaDenier »

ArcticMelt2

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #36 on: August 03, 2020, 06:07:48 PM »
Was the last significant spall of the Canadian shelf in 2011?

https://wirl.carleton.ca/research/ice/ice-shelves/calving-2011/

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #37 on: August 04, 2020, 01:13:12 AM »
Gif showing the break off from the Milne Ice Shelf, using the sentinel images 29th and 31st July.

Click to run
« Last Edit: August 04, 2020, 01:34:13 AM by Niall Dollard »

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #38 on: August 04, 2020, 11:02:34 AM »
Here is another shot, still something left though:
Please click on image to animate!
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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #39 on: August 05, 2020, 12:01:38 AM »
Does anyone know, and when large cracks formed along which a separation occurred?

These cracks are clearly visible even in the 1959 image!

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2011JF002074

It was a really stable ice shelf. Since the 50s of the 20th century, only one small spall.

https://www.tandfonline.com/doi/pdf/10.1080/00040851.1986.12004103

Quote
At the west side of the outer unit, two of the three radial cracks shown in the 1959 photographs created a structural weakness in the ice shelf. It is now known that at some time between 1959 and 1974, a 33 km2 ice island calved from this part of Milne Ice Shelf (Jeffries, 1986).
« Last Edit: August 05, 2020, 12:58:30 AM by ArcticMelt2 »

Niall Dollard

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Re: Ice Shelves /Ward Hunt Ice Shelf / Ellesmere Island / Canada
« Reply #40 on: August 05, 2020, 09:54:43 AM »
Milne ice shelf has reduced in area by 43% according to Canadian ice service.

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Has the new ice island already split in two? And again along the big crack ...

Apparently, these large cracks were formed during the last great warming, in the 30s of the 20th century. The new spall increases the loss of the Canadian Arctic Ice Shelf after 1906 from 94 to 95%. But the period after 1998 accounted for only 7% of all losses after 1906. Almost 90 percent of the losses appear to have occurred during the warming of the 1930s. Then these large cracks formed. There was little research on ice shelves at the time.

https://link.springer.com/chapter/10.1007%2F978-94-024-1101-0_5

Quote
The ice shelves along the northern coast of Ellesmere Island have been in a state of decline since at least the early twentieth century. Available data derived from explorers’ journals, aerial photographs and satellite imagery have been compiled into a single geospatial database of ice shelf and glacier ice tongue extent over 13 observation periods between 1906 and 2015. During this time there was a loss of 8,061 km2 (94%) in ice shelf area. The vast majority of this loss occurred via episodic calving, in particular during the first six decades of the twentieth century. More recently, between 1998 and 2015, 515 km2 of shelf ice calved.