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Author Topic: NEGIS outlet  (Read 8299 times)

ivica

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NEGIS outlet
« on: February 22, 2013, 06:26:04 PM »
"The effect of the north-east ice stream on the Greenland ice sheet in changing climates" by R. Greve and S. Otsu, 2007.

"The Jakobshavn ice stream (JIS) in central west Greenland is a highly localized fast-flow feature,
the speed of which has doubled since 1995 and reaches extremely large values of up to 13 km/a (Joughin et al., 2004).
By contrast, the north-east Greenland ice stream (NEGIS), discovered first by European Space Agency's ERS-1 satellite,
is a large fast-flow feature with a length of ~500 km and a maximum width of ~100 km. The NEGIS branches into three major
outlet glaciers close to the coast, where flow velocities of up to 1.2 km/a are reached (Joughin et al., 2001),
an order of magnitude less than for the JIS."
http://hal.archives-ouvertes.fr/hal-00298522/

Coast around outlets is usually clogged with sea ice and that is also helped by small islands there.

2008-07-31: Watching MODIS imaginary for that area I did catch this:

11:00 UTC: 
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2008213110001-2008213110500.4km.jpg


15:30 UTC: 
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2008213153000-2008213153501.4km.jpg


My rude estimate:
9000 km^2 of 5 years old sea ice cracked in a couple of hours, cracks a mile+ wide and 60+ miles long.

Speed of cracks opening, sounds accompanied, burst of sea filling empty space...total scene... exceeds my imagination.
I was highly impressed by that moment!
What to think about huge cracks in Arctic reported on Neven's blog this winter ?
Interesting melt season follows.

Jim Hunt

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Re: NEGIS outlet
« Reply #1 on: February 22, 2013, 09:37:34 PM »
See also Zachariæ Isstrøm Further Retreat, courtesy of Mauri Pelto:

Quote
In northern Greenland high velocities extend far inland only on Zachariae and Petermann Glacier tapping into the midst of the ice sheet in northern Greenland. Further, it is the Zachariae Isstrøm (ZIS) that is likely the only of this group that would be comparable to a bank that is too big to fail as its increased velocity band extends well into the ice sheet.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

ivica

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Re: NEGIS outlet
« Reply #2 on: February 23, 2013, 09:14:39 AM »
Ah, fresh information, thank you Jim  :)

ivica

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Re: NEGIS outlet
« Reply #3 on: March 23, 2013, 08:54:13 AM »
Photo attached, NEGIS shore area yesterday.
Credits: EOSDIS WorldView

I wonder how much ice (if any) will remain on that shore this season.

gfwellman

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Re: NEGIS outlet
« Reply #4 on: March 23, 2013, 09:15:21 AM »
I would think we'd see a new minimum in the fast ice up there, perhaps only leaving sections protected by those offshore islands.  Luckily, I don't think that should have any large effect on the the mainland ice sheet.  It's not like when a large ice shelf actually contributes to holding back glacial flow, and thus breakup of the shelf leads to accelerated mass loss.  Of course longer term, the trend to less fast ice will be a trend to warmer temperatures at the edge of the ice sheet, and that's not good.

ivica

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Re: NEGIS outlet
« Reply #5 on: March 28, 2013, 01:15:26 PM »
Basic info/links related to the area:

EastGreenland portal contains a lot of info, for example see
articles about Station Nord and The Sirius Patrol in National Park section.

Weather forecast/statistic for Station Nord:  at DMI,
at Wunderground (Nord), at Wunderground (Nord Aws)

Weather forecast/statistic for Danmarkshavn: at DMI, at Wunderground

No webcam known to me there.

NEGIS Outlets:
   Nioghalvfjerds Glacier (Nioghalvfjerdsbræ, 79 Glacier)
   Zachariae Ice Stream (Zachariæ Isstrøm, ZIS)
   Storstrommen

Map of NEGIS area, attached:
« Last Edit: June 24, 2013, 10:21:03 AM by ivica »

Espen

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Re: NEGIS outlet
« Reply #6 on: April 02, 2013, 09:15:53 AM »
Ivica;

""I wonder how much ice (if any) will remain on that shore this season.""

I studied that earlier, the area was more or less Sea Ice Free in the early 2000s, 2 years in a row I recall, and the same happened in the early 90s, so there is a "natural" clearance every 10 - 12 years, but that said, I believe the Sea Ice  will disappear this season in the "Lagoon".
I will also be interesting to watch the Zachariæ Isstrøm (ZIS) reaction to split of the the tongue that happened last year (south of Lambert Land/ Kap Zacharaiae), will ZISs flow accelerate?
Have a ice day!

ivica

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Re: NEGIS outlet
« Reply #7 on: June 24, 2013, 12:16:33 AM »
Espen, thanks for adding your observation here.

Copying link to Nioghalvfjerdsbræ (79) Glacier, Northeast Greenland article by Mauri Pelto (June 18, 2013) brought by mspelto on other thread.

ivica

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Re: NEGIS outlet
« Reply #8 on: June 24, 2013, 10:37:31 AM »
2003. & 2012. clearing of NEGIS shore posted by Espen:



September 2012. days of clear view of ZIS: 3, 12, 25.
« Last Edit: June 24, 2013, 11:41:32 AM by ivica »

mspelto

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Re: NEGIS outlet
« Reply #9 on: June 27, 2013, 05:01:47 PM »

Zachariae from June 17 2013 indicating with yellow dots all of the new icebergs from late 2012 and the new ice front.