Author Topic: The Nares Strait thread (Read 1062692 times)

Espen · « **Reply #50 on:** July 10, 2013, 09:42:53 AM »

Only hours or few days away from the Grand Opening of Nares Strait:

Espen · « **Reply #51 on:** July 10, 2013, 02:24:25 PM »

July 10 2013 later:

Espen · « **Reply #52 on:** July 10, 2013, 08:10:19 PM »

Break up is on the way.

Click on image to enlarge!

Espen · « **Reply #53 on:** July 11, 2013, 07:40:18 AM »

The Nares Express is ready to leave:

Neven · « **Reply #54 on:** July 11, 2013, 07:55:21 AM »

Thanks for the update and image, Espen! I have just written a post for the ASIB that will be published tonight.

Espen · « **Reply #55 on:** July 11, 2013, 11:11:25 AM »

Watching the disintegration of sea ice in Nares Strait over the last couple of days, I realize I was probably wrong when stating earlier to Terry that P2-2012 had no influence on the break up of sea ice in the Strait.
I now see that P2-2012 is actually sitting far more in the center of the Strait than I thought, and to me it is now clear it is to some extend blocking the ice from moving south thru Smith Sound and Baffin Bay.

The yellow spot spot on image below is P2/2012.

Espen · « **Reply #56 on:** July 11, 2013, 03:18:56 PM »

Latest image from Nares Strait / Kane Basin:

Tor Bejnar · « **Reply #57 on:** July 11, 2013, 03:59:51 PM »

A bathymetric map of Nares Strait is at http://icyseas.org/2012/09/02/petermann-ice-island-2012-breaking-up/. From this article, the Petermann Ice Island was (is?) about 144 meters thick. It clearly remains grounded, as it has not moved since last (northern hemisphere) autumn (even as the ice around it breaks up and floats southward). The ice island appears to be stuck about where the tiny 100 m contour (just a point on the map) is.

TerryM · « **Reply #58 on:** July 11, 2013, 07:14:20 PM »

I'm seeing a very small movement south for PII2012-A-1 using Arctic.io's split zoom. Todays images still aren't up yet so I've been comparing 7-7 to 7-10.
It's certainly moving much slower than the surrounding ice and may actually be rotating slightly rather than moving southward so I assume the keel is grounded to some extent. It wasn't enough to maintain the ice bridge but it may have kept it in place for one tide cycle.
If it did maintain the ice bridge for an additional 14 days, that could have an effect on the Sept. minimum.
We won't have another spring tide for another 10 days. It will be interesting to see if it's still grounded after that.

Terry

TerryM · « **Reply #59 on:** July 11, 2013, 08:57:02 PM »

Ice island is definitely rotating in a clockwise direction by perhaps 15 degrees since yesterday.

Terry

Wipneus · « **Reply #60 on:** July 12, 2013, 08:40:49 AM »

Here is how Uni-Hamburgs AMSR2 sea ice concentration sees it.

(red concentration going below 15%, blue going above 15%)

Espen · « **Reply #61 on:** July 12, 2013, 10:40:44 PM »

I am somehow confused how the ice is behaving in the Strait, to be honest.

no1der · « **Reply #62 on:** July 13, 2013, 02:55:03 AM »

Quote from: TerryM on July 11, 2013, 08:57:02 PM

Ice island is definitely rotating in a clockwise direction by perhaps 15 degrees since yesterday.

Terry

From overlaying the last 3 days of images, I see that the ice island is indeed rotating clockwise. The pivot point is near its southern, Greenland-facing end, where it must have fetched up on a shoal. The island is sweeping around to the east, against the flow of escaping ice (!??).

Tor Bejnar · « **Reply #63 on:** July 13, 2013, 06:32:06 AM »

I overlapped the last clear MODIS image with one from a week ago. This showed the rotation of the Petermann Ice Island, but also seemed to show that it moved SW-ward (down stream) a km or so.

Having spent so many months stuck on a rock and fairly fixed in place by fast ice, I expect flowing water scoured the ice at the grounding site, and once free (or partially free), a new location on the ice island is connecting with the bottom. It might rotate free or stay stuck for a while, for all I know!

Phil. · « **Reply #64 on:** July 13, 2013, 09:39:42 PM »

Here's the latest, lot's of disintegration!
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2013194171000-2013194171500.250m.jpg

Espen · « **Reply #65 on:** July 13, 2013, 10:05:20 PM »

Quote from: Phil. on July 13, 2013, 09:39:42 PM

Here's the latest, lot's of disintegration!
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2013194171000-2013194171500.250m.jpg

Thanks to Phil, I thought it would be quite up there today, but obviously not:
Cracks developed close to Petermann Fjord, this afternoon.

Phil. · « **Reply #66 on:** July 14, 2013, 01:05:10 AM »

Quote from: Espen on July 13, 2013, 10:05:20 PM

Thanks to Phil, I thought it would be quite up there today, but obviously not:
Cracks developed close to Petermann Fjord, this afternoon.

Yes Espen the section south of Petermann broke up into lots of small floes today and it's still continuing, tomorrow should be interesting.

ghoti · « **Reply #67 on:** July 14, 2013, 08:43:23 PM »

The ice in the Nares has been moving in opposite directions everyday this week almost as if sloshing back and forth in a tub. Is this the usual behaviour in the Nares? Are the winds shifting that dramatically each day?

Espen · « **Reply #68 on:** July 15, 2013, 08:43:26 AM »

The break down continues:

Espen · « **Reply #69 on:** July 15, 2013, 02:29:07 PM »

Latest image:

Espen · « **Reply #70 on:** July 16, 2013, 01:49:06 PM »

Congestion ahead of Smith Sound.

Click on image to enlarge!

TerryM · « **Reply #71 on:** July 16, 2013, 04:03:27 PM »

Still no advection through Nares.

I thought Nares might be slow to open up but didn't expect it to be this late.
We're experiencing a neap tide at present and I expect Hall Basin and the rest to be open well before the spring tides of the 22nd.

It seems as though PII2012-A-1 is still too thick to make much progress through Kane Basin. IIRC it was about twice as thick as the Great Pyramid of Giza is tall when it first broke free.
The spring tide on the 22nd, while not as strong as the proxigean tide we just experienced, is still the strongest for the rest of the melt season. If our ice island doesn't find a way south it's possible it could stay in place for at least another year.
If it should withstand the summer flow through Nares it could remain an obstacle to next year's breakup, again slowing the start of advection from Lincoln Sea.

Terry

Espen · « **Reply #72 on:** July 19, 2013, 09:02:48 AM »

Very little action observed in Nares Strait, and very different to recent years:

Neven · « **Reply #73 on:** July 19, 2013, 11:23:44 AM »

Is it me or is there a lot of in situ melting?

Espen · « **Reply #74 on:** July 19, 2013, 11:29:37 AM »

For the time being it can only be in situ melting, since the ice seems to be stuck inside Nares Strait, due to currents, wind or other causes (Pll -2012?)!

TerryM · « **Reply #75 on:** July 19, 2013, 10:42:09 PM »

Espen
The images highlighting PII-2012-A-1 are really handy, shows how far south the ice has been moving.
As of today the ice in Hall Basin is holding firm. There is a strong counterclockwise gyre in Hall Basin (3 or 4 days to make a circuit as I recall) so I can't imagine any kind of ice bridge forming.
Advection from Lincoln Sea is going to start very late this year. Han island reported 10c yesterday so in situ melt should be expected.
I don't know if anyone else is intrigued by accounts of expeditions into Nares but I'm including a blog from 2009 aboard Arctic Sunrise.
http://soi.st-andrews.ac.uk/pageset.aspx?psr=495

Terry

danp · « **Reply #76 on:** July 20, 2013, 05:57:59 AM »

48 hours of motion, from processing ch. 1-4-3 of MODIS swaths. Note the time stamps as the delay between frames is pretty irregular (it depends on the vagaries of satellite overpasses). You can definitely see some currents or wind shoving ice back up against the southern edge of the jam, as well as the role of Peterman ice island forcing the ice around it.

Alistair · « **Reply #77 on:** July 20, 2013, 06:54:19 PM »

Thanks Danp that really shows how grounded PII-2012 is.

Espen · « **Reply #78 on:** July 21, 2013, 03:59:43 PM »

Peaking trough the clouds above Hall Basin Nares Strait, cracks now appear in front of Petermann Fjord / Hall Basin:

Espen · « **Reply #79 on:** July 21, 2013, 05:19:28 PM »

P II - 2012 is still left behind in the Nares Chaos:

TerryM · « **Reply #80 on:** July 21, 2013, 06:02:32 PM »

Espen
Great images!

I think when PII-2012-A-1 drifted toward the center of the channel last October (after the lights went out) it removed itself from the deepest channel and has run into a dead end trough from which it can't escape. The bathymetry isn't too clear but it seems as though there are shallower areas on three sides now. It may stay stuck there until the keel melts back or fractures.

From Arctic.io's split zoom is appears as though the dates for advection are:
2010 - July 10
2011 - July 5
2012 - July 8
2013 - July 21 and counting

The tides are increasing each cycle until spring tide on the 22nd & I think we should have advection by then. If PII2012-A-1 is still in place by the 24th it may be a permanent feature (for another year or so).

I don't know what effect the late advection will have in the Lincoln Sea or whether this is going to be an annual event as long as PII2012-A-1 remains. I'd assume that allowing MYI to build would slow melt in the eastern side of the CAA a well as the CAB. However almost all predictions I make based on something that I think I understand prove wrong [size=78%]

Terry

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Espen · « **Reply #81 on:** July 22, 2013, 02:25:27 PM »

As indicated yesterday the cracks in front of Petermann Fjord are now showing up:

Espen · « **Reply #82 on:** July 22, 2013, 06:48:31 PM »

Further action in the Strait:

1 or 2 days more we see ice moving out of Petermann Fjord.

Click on image to enlarge!

Phil. · « **Reply #83 on:** July 23, 2013, 05:14:37 AM »

More movement:
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2013203233500-2013203234000.250m.jpg

Phil. · « **Reply #84 on:** July 23, 2013, 04:19:46 PM »

Quote from: Espen on July 22, 2013, 06:48:31 PM

Further action in the Strait:

1 or 2 days more we see ice moving out of Petermann Fjord.

Click on image to enlarge!

Today's Aqua image shows more action in the Hall basin.

Espen · « **Reply #85 on:** July 23, 2013, 06:56:02 PM »

P2-2012 is still left behind in the chaos of Nares:

Please click on image to enlarge!

Jmo · « **Reply #86 on:** July 25, 2013, 08:46:10 AM »

Espen and other aficionados.

You've been looking at these things for far longer than I. It amazes how quickly things are changing in Nares. Obviously it just takes the right conditions to develop over some time and then off it goes? Truly looks like solid breakup, but also significant in situ melt? Just noticing how the ice is rapidly becoming bluer (or an artifact of the satellite image?) and also the edges "smooth" off. Nares Express really close to fully opening now.

Espen · « **Reply #87 on:** July 25, 2013, 08:53:43 AM »

JMO;

Yes in the CAA (Canadian Arctic Archipelago) and Nares in situ melting is often seen, and it is in my opinion a "small" test bed for the rest of the Arctic Ocean, I always argued the over nite scenario where the sea ice "evaporates" very quickly.

Phil. · « **Reply #88 on:** July 26, 2013, 04:22:36 PM »

Although it's cloudy the latest MODIS is showing significant melting opposite the mouth of the Petermann glacier (particularly Archer fjord). Location near the center of the image.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2013207103000-2013207103500.250m.jpg

Espen · « **Reply #89 on:** July 26, 2013, 04:38:22 PM »

Phil;

Yes I have noticed it is about half empty of ice, and looks as Hall Basin is pretty empty too, wonder what is going in the P-fjord. Bad we don't have the radar images anymore!

Espen · « **Reply #90 on:** July 26, 2013, 07:04:49 PM »

Nares Strait is beginning to pull sea ice in from Lincoln Sea:

Heavy clouds over Nares Strait.

ghoti · « **Reply #91 on:** July 26, 2013, 11:11:56 PM »

Where is buoy 2013C relative to that open water at the Nares / Lincoln interface?

Espen · « **Reply #92 on:** July 26, 2013, 11:26:11 PM »

Its about 25 km form Cape Belknap (just north of Alert ,Ellesmere Island) or about 70 km from the entrance of Nares Strait (centerline).

Espen · « **Reply #93 on:** July 29, 2013, 07:58:36 PM »

Nares Strait and in particular Kane Basin is crowded this season and I believe the culprit is PII-2012.

Click on image to enlarge and better details!

TerryM · « **Reply #94 on:** July 30, 2013, 02:36:16 AM »

Espen
I'm not yet willing to claim that Nares Strait is open to advection even though Hall Basin is clear. The latest date I've found was in 2009 at July 14th. PII20112-A-1 has made a huge difference in the timing of the start of advection and as you point out may now be impeding the flow.
My guess is that it will survive this melt season, and possibly the next few seasons as well.

Terry

Phil. · « **Reply #95 on:** July 31, 2013, 12:36:09 AM »

The stalled ice island definitely appears to impede progress but my impression is that the wind/current is headed north at present. See for example the open water to the N of the island and the lack of progress of the ice pieces to the South which wouldn't be obstructed by the ice island.

Tor Bejnar · « **Reply #96 on:** July 31, 2013, 02:25:57 PM »

I agree, Phil. I've read that water routinely flows both 'north' and 'south' in Nares Strait, and I have observed icebergs moving around (counterclockwise) in a gyre within Kane Basin in previous years. (I've not studied this this year.) Obviously, any island (rock or ice) will impede movement, but I do not think PII-2012 is particularly keeping ice from Smith Strait. (I do expect PII-2012 delayed Nares Strait from opening, however.)

Phil. · « **Reply #97 on:** July 31, 2013, 03:01:13 PM »

Today's MODIS image posted by Espen shows a slight northern flow and in situ melting compared with earlier images.

Phil. · « **Reply #98 on:** August 04, 2013, 08:14:20 PM »

Quote from: Phil. on July 31, 2013, 03:01:13 PM

Today's MODIS image posted by Espen shows a slight northern flow and in situ melting compared with earlier images.

The latest Modis view of the Nares seems to be starting to clear again, looks like the southerly flow has restarted.
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2013216134000-2013216134500.2km.jpg

Phil. · « **Reply #99 on:** August 08, 2013, 10:32:40 PM »

A good clear look at the Nares today on MODIS shows further clearing and floes entering from the North.
Petermann fjord also showing melting out of the seaice back towards the glacier.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2013220131500-2013220132000.2km.jpg

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Author Topic: The Nares Strait thread (Read 1062692 times)