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jai mitchell

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Re: The Nares Strait thread
« Reply #1150 on: June 17, 2017, 04:18:13 PM »
LaPresse blames the cancellation of the Amundsen's mission on the failure of the Nares arch: http://www.lapresse.ca/environnement/climat/201706/13/01-5106982-les-changements-climatiques-coulent-une-mission-scientifique.php

Quote
Des embâcles se forment habituellement au printemps dans le détroit de Nares, entre le Groenland et l'île d'Ellesmere, empêchant la banquise de descendre vers le sud. Cette année, la glace trop mince et trop molle a empêché la formation des embâcles, si bien que d'énormes quantités de glace ont descendu vers le sud, s'accumulant notamment entre l'île de Terre-Neuve et le Labrador. Voyant cela, la Garde côtière n'a eu d'autre choix que d'envoyer l'Amundsen à la rescousse, son seul brise-glace de calibre suffisant alors en état de naviguer.

(My translation): "Ice jams normally form in spring in the Nares Strait, between Greenland and Ellsmere Island, stopping the sea ice from flowing South. This year, thin and soft ice prevented the ice jams from forming, so that enormous quantities of ice flowed South, accumulating notably between the island of Newfoundland and the Labrador mainland. The Coast Guard had no choice but to send the Amundsen to the rescue, it being the Coast Guard's only operable ice breaker."

More details in the story, largely based on an interview with Barber from U.Manitoba.

I am unsure about the scale of impact, but the abnormality of much older/thicker floes into the Hudson (5-8m!!!) will cause a lower rate of SIE loss in the Northern Hemisphere graph, since these flows will persist much longer through the melt season.  However, it would also necessarily lead to more rapid losses later in the season (August cliff).
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1151 on: June 17, 2017, 05:42:51 PM »
...Tor, you should be able to see the different tinge here (I hope).
Thanks, but I see grays and whites, not any bluishness.  Some of the difference between the two images is obviously due to clouds.  I definitely see differences in grayness in areas that appear not to have clouds in either image.  I'm gonna just trust others' sightedness!  8)
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magnamentis

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Re: The Nares Strait thread
« Reply #1152 on: June 17, 2017, 05:47:24 PM »
LaPresse blames the cancellation of the Amundsen's mission on the failure of the Nares arch: http://www.lapresse.ca/environnement/climat/201706/13/01-5106982-les-changements-climatiques-coulent-une-mission-scientifique.php

Quote
Des embâcles se forment habituellement au printemps dans le détroit de Nares, entre le Groenland et l'île d'Ellesmere, empêchant la banquise de descendre vers le sud. Cette année, la glace trop mince et trop molle a empêché la formation des embâcles, si bien que d'énormes quantités de glace ont descendu vers le sud, s'accumulant notamment entre l'île de Terre-Neuve et le Labrador. Voyant cela, la Garde côtière n'a eu d'autre choix que d'envoyer l'Amundsen à la rescousse, son seul brise-glace de calibre suffisant alors en état de naviguer.

(My translation): "Ice jams normally form in spring in the Nares Strait, between Greenland and Ellsmere Island, stopping the sea ice from flowing South. This year, thin and soft ice prevented the ice jams from forming, so that enormous quantities of ice flowed South, accumulating notably between the island of Newfoundland and the Labrador mainland. The Coast Guard had no choice but to send the Amundsen to the rescue, it being the Coast Guard's only operable ice breaker."

More details in the story, largely based on an interview with Barber from U.Manitoba.

I am unsure about the scale of impact, but the abnormality of much older/thicker floes into the Hudson (5-8m!!!) will cause a lower rate of SIE loss in the Northern Hemisphere graph, since these flows will persist much longer through the melt season.  However, it would also necessarily lead to more rapid losses later in the season (August cliff).

those floes and that kind of thickness are only exceptions and as far as i can see are not present in significant amounts/numbers. hence i believe that their presence there does not have the slightest impact on any statistics with less than 2 digits after the comma.

further hudson is quite far south and mostly melts out, hence those few "bergs/floes" or whatever they are,  will mostly melt like butter later in the season as you mentioned yourself.

don't hesitate to let me know if and why you disagree with what i said, one can easily miss something, specially one who's reading and writing around 10h a day LOL

Jim Hunt

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Re: The Nares Strait thread
« Reply #1153 on: June 17, 2017, 06:28:51 PM »
I am unsure about the scale of impact, but the abnormality of much older/thicker floes into the Hudson (5-8m!!!

The "older/thicker floes" aren't "into the Hudson" are they? According to the CBC report:

Quote
The icebreaker was diverted from its course to help ferries and fishing boats navigate the Strait of Belle Isle. "The requirements for search and rescue trumped the requirements for science," said Barber.

Assorted journos seem to have got hold of the wrong end of the stick.
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jai mitchell

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Re: The Nares Strait thread
« Reply #1154 on: June 17, 2017, 09:10:45 PM »

don't hesitate to let me know if and why you disagree with what i said, one can easily miss something, specially one who's reading and writing around 10h a day LOL

No, that sounds quite rational.  I guess I am also conflating the perception of much older and thicker ice from the Fram, as reported by Icebridge in (May?) 
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Re: The Nares Strait thread
« Reply #1155 on: June 17, 2017, 11:19:07 PM »
The thickest ice off Labrador and Newfoundland (excluding icebergs) originates mostly in the Lincoln Sea and passes south through Nares Strait. We observed ice draft every 10 seconds from 2003 through 2012 and ice thicker than 5-m occurs, but is very rare, about 5% of the time. The peer reviewed paper is at

http://muenchow.cms.udel.edu/papers/RyanMuenchow2017.pdf

 
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1156 on: June 18, 2017, 12:41:47 AM »
Thanks for your paper, Andreas [http://muenchow.cms.udel.edu/papers/RyanMuenchow2017.pdf]  It puts real (previous year) numbers to my speculations of this spring's ice export in this thread!

I'm sure the thick ice floes seen near Labrador got there before the Lincoln Sea ice bridge formed in early February 2017 (that broke in early May), but how long before, I wonder - October-November 2016?
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magnamentis

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Re: The Nares Strait thread
« Reply #1157 on: June 18, 2017, 02:21:08 AM »
The thickest ice off Labrador and Newfoundland (excluding icebergs) originates mostly in the Lincoln Sea and passes south through Nares Strait. We observed ice draft every 10 seconds from 2003 through 2012 and ice thicker than 5-m occurs, but is very rare, about 5% of the time. The peer reviewed paper is at

http://muenchow.cms.udel.edu/papers/RyanMuenchow2017.pdf

thanks a lot, very helpful, sheds some light for me and others who are not extremely privy with that.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1158 on: June 19, 2017, 08:34:01 PM »
A largish floe, from the (probably) thickest former-Greenland-fast-ice is just entering Robeson Channel (northern Nares Strait).  As the winds, according to Windytv, will generally not be supportive of a quick trip down the Nares, will this floe get stuck on Joe or Hans Islands?  ...
This 'largish floe', apparently, bumped the Greenland coast upon entering Robeson Channel and broke.  The largest piece has passed Joe Island (near the mouth of Petermann Fjord) and is making its way south, probably a couple days away from Hans Island.  It looks like it could slip by, but it will probably hit poor Hans.  If Andreas's recording devices remain pointing up from the Kennedy Channel depths, we may some day know how thick this floe is (was)!
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1159 on: June 21, 2017, 04:42:24 PM »
We may know this afternoon (eastern North America time) how intact 'largish floe' remains after its (at least) close encounter with Hans Island.  (Yesterday's DMI Sentinel image annotated screen print of Kennedy Channel)
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Re: The Nares Strait thread
« Reply #1160 on: June 21, 2017, 04:49:11 PM »
We may know this afternoon (eastern North America time) how intact 'largish floe' remains after its (at least) close encounter with Hans Island.  (Yesterday's DMI Sentinel image annotated screen print of Kennedy Channel)

Right now it appears to be jammed up against the island but still intact according to MODIS.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017172084000-2017172084500.250m.jpg

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1161 on: June 21, 2017, 06:10:02 PM »
Yup (I rotated [then cropped] a screen print from Phil's link - and it is now afternoon here  ;D)
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Clenchie

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Re: The Nares Strait thread
« Reply #1162 on: June 21, 2017, 07:33:08 PM »
Yup (I rotated [then cropped] a screen print from Phil's link - and it is now afternoon here  ;D)

It is further down now.
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1163 on: June 21, 2017, 08:13:46 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)
« Last Edit: June 21, 2017, 08:18:49 PM by Tor Bejnar »
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gerontocrat

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Re: The Nares Strait thread
« Reply #1164 on: June 21, 2017, 09:00:33 PM »
Is Hans Island a lump of solid rock or is it just a heap of accumulated glacial debris ?
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1165 on: June 21, 2017, 09:05:57 PM »
Quote
Hans Island is interesting to geologists because it's part of a mountain chain that starts in the Svalbard Islands off Norway, runs through Greenland, and pokes out again in Ellesmere Island.Apr 9, 2004
Greenland, Canada squabbling over pet rock - Nunatsiaq News
www.nunatsiaqonline.ca/archives/40409/news/nunavut/40409_08.html
That is:  it is solid rock.
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gerontocrat

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Re: The Nares Strait thread
« Reply #1166 on: June 21, 2017, 09:15:53 PM »
Quote
Hans Island is interesting to geologists because it's part of a mountain chain that starts in the Svalbard Islands off Norway, runs through Greenland, and pokes out again in Ellesmere Island.Apr 9, 2004
Greenland, Canada squabbling over pet rock - Nunatsiaq News
www.nunatsiaqonline.ca/archives/40409/news/nunavut/40409_08.html
That is:  it is solid rock.

Given its position obstructing traffic on the Nares Strait Lincoln Sea Ice Motorway (Autostrada, Freeway) is there any data regarding its diminuition in size due to frequent collisions with self-driving lumps of ice ?
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Re: The Nares Strait thread
« Reply #1167 on: June 21, 2017, 09:35:50 PM »
Looks like a little more ice is about to break from Humbolt, new moon on the 24th should get it moving south.

Phil.

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Re: The Nares Strait thread
« Reply #1168 on: June 22, 2017, 02:50:43 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

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Re: The Nares Strait thread
« Reply #1169 on: June 22, 2017, 03:52:01 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

It is surprising how fast such a large floe can proceed down the channel.
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1170 on: June 22, 2017, 07:02:52 PM »
...
Given [Hans Island's] position obstructing traffic on the Nares Strait Lincoln Sea Ice Motorway (Autostrada, Freeway) is there any data regarding its diminuition in size due to frequent collisions with self-driving lumps of ice ?
I expect one might feel some of those lumps of ice hitting the island, but they will have a tiny affect on its size.  The Ice Age glaciers that carved Nares Strait continually dragged a giant's equivalent of sandpaper against it, and were able to put a lot of umph into their work, yet "decided" to leave its remnants alone.  But the way, it is composed of Silurian aged limestone, per this  1931 map (via Geo. Survey of Denmark)
(Interesting that Petermann Fjord had a different name then.)
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Clenchie

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Re: The Nares Strait thread
« Reply #1171 on: June 22, 2017, 07:16:17 PM »
...
Given [Hans Island's] position obstructing traffic on the Nares Strait Lincoln Sea Ice Motorway (Autostrada, Freeway) is there any data regarding its diminuition in size due to frequent collisions with self-driving lumps of ice ?
I expect one might feel some of those lumps of ice hitting the island, but they will have a tiny affect on its size.  The Ice Age glaciers that carved Nares Strait continually dragged a giant's equivalent of sandpaper against it, and were able to put a lot of umph into their work, yet "decided" to leave its remnants alone.  But the way, it is composed of Silurian aged limestone, per this  1931 map (via Geo. Survey of Denmark)
(Interesting that Petermann Fjord had a different name then.)


It doesn't look that high so I guess it will one day be below sea level. Thanks to Tor Bejnar for pointing out the height is 150m - 170m, which means that it will remain above sea level even if the most pessimistic sea level predictions are manifested.
« Last Edit: June 22, 2017, 08:29:51 PM by Clenchie »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1172 on: June 22, 2017, 07:56:32 PM »
From the first paragraph of the above referenced Geo. Survey of Denmark paper:
Quote
... Rising less than 170 m above normally ice-infested waters, the 1.25 km2 island is physiographically far overshadowed by nearby Franklin Ø (Fig. 1).

Referencing "Government of Canada, (1985) Sailing Directions, Arctic Canada, Vol. 2, Ottawa: Canadian Hydrographic Service", this Canada's Unresolved maritime Boundaries paper) reports:
Quote
Hans Island (80° 49’N, 66° 28’W) is described as being sandy in colour with a cliff at its south end of about 150m in elevation.
  This would be the height of the cliff.

Finally, from Hans Island: Meteorological Data From an International Borderline:
Quote
Hans Island (80º49’35’N, 66º27’35’W) is a small sandstone landform that occupies an area of about 1.3 square kilometers and is 168 meters in height (Figure 1a).
"Sandstone"  Hmmmm.
« Last Edit: June 22, 2017, 08:20:43 PM by Tor Bejnar »
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gerontocrat

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Re: The Nares Strait thread
« Reply #1173 on: June 22, 2017, 08:49:39 PM »
From the first paragraph of the above referenced Geo. Survey of Denmark paper:
Quote
... Rising less than 170 m above normally ice-infested waters, the 1.25 km2 island is physiographically far overshadowed by nearby Franklin Ø (Fig. 1).

Referencing "Government of Canada, (1985) Sailing Directions, Arctic Canada, Vol. 2, Ottawa: Canadian Hydrographic Service", this Canada's Unresolved maritime Boundaries paper) reports:
Quote
Hans Island (80° 49’N, 66° 28’W) is described as being sandy in colour with a cliff at its south end of about 150m in elevation.
  This would be the height of the cliff.

Finally, from Hans Island: Meteorological Data From an International Borderline:
Quote
Hans Island (80º49’35’N, 66º27’35’W) is a small sandstone landform that occupies an area of about 1.3 square kilometers and is 168 meters in height (Figure 1a).
"Sandstone"  Hmmmm.
Looks more like dolomite to me. That horizontal stratigraphy also reminiscent of periodic deposits of calcium carbonate in shallow warm seas?
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RoxTheGeologist

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Re: The Nares Strait thread
« Reply #1174 on: June 22, 2017, 09:30:46 PM »
Looks like its limestone and dolomites

Its old! Silurian, and not metamorphosed, which illustrated how stable the shield has been.

Ludlovian in age (named after the original type locality of Ludlow, Shropshire)

Tectonic setting is of a continental margin.


Kap Morton Formation (M)
Name. Hurst (1980a).
Other literature. Hurst (1981), Peel (1984), de Freitas
et al. (1993).
Age. Middle to Late Silurian.
Thickness and lithology. This map unit of shallowly
dipping, well-bedded, mainly pale carbonates, about
450 m thick, occurs on the west side of John Brown
Iskappe overlying map unit G, and forms the c. 200 m
succession on Hans Ø in mid-Kennedy Channel. It
corresponds to the Kap Morton Formation of Hurst
(1980a), but also includes strata referred to the Kap
Godfred Hansen and Pentamerus Bjerge Formations
(see Hurst 1980a, figs 24, 28). In the highest ground
fringing the ice cap, it includes a stratal interval that
probably equates with the Kap Maynard Formation (Fig.
38
20). Described in the literature mainly from sections
north of the map sheet, the lower part of the map unit
comprises massive, light grey, lime mudstones with
incursions of bioclastic limestone and resedimented
carbonate conglomerate. On Hans Ø, where the section
is characterised by alternating pale and darker
carbonates that are in part dolomitised, a pinnacle reef
occurs together with stromatoporoid- and coral-rich
biostromal beds (see de Freitas et al. 1993, fig. 7). The
lime mudstones, both in Washington Land and on Hans
Ø, are characterised by articulate megalodont bivalves
(see Hurst 1980a, fig. 50; de Freitas 1990, fig. 2; de
Freitas et al. 1993, fig. 4). The lithology of the upper
part of the map unit is poorly known, but on aerial
photographs it has the same well-layered character as
the lower strata, and to the succession north of the
map sheet referred by Hurst (1980a) and Jepsen et al.
(1983) to the Kap Maynard Formation. The Hans Ø
succession, with its Ludlow fauna, was referred to the
Kap Maynard Formation by de Freitas et al. (1993, fig.
5), but is placed here in the Kap Morton Formation.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1175 on: June 22, 2017, 09:57:52 PM »
Thanks, Rox!
From the Canadian geological map of the Arctic, here is a screen shot of the Kennedy Channel area.  The added red arrow points to about where Hans Island would be.  Franklin Island is shown, and is colored a 'green' that is identified "S4" elsewhere.  The legend identifies "S4" as being Silurian carbonates.
« Last Edit: June 22, 2017, 10:03:34 PM by Tor Bejnar »
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gerontocrat

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Re: The Nares Strait thread
« Reply #1176 on: June 22, 2017, 10:04:00 PM »
Being a mixture of limestone and domolitised limestone, Hans Island will be there for a very long time after there is no ice left to wear it away. But it was nice to see that some of the geology I learnt 50 years ago is still lurking in forgotten areas of the cerebrum.
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Re: The Nares Strait thread
« Reply #1177 on: June 23, 2017, 02:45:29 PM »
cross post:
Perhaps this is obvious, but I haven't seen it mentioned that every chunk of ice exported through the Fram or elsewhere into warmer non-arctic waters is equivalent to the latent heat necessary to melt that ice imported directly to the arctic ice. According to this paper
http://www.the-cryosphere.net/11/65/2017/
export has since 1935 averaged about 880,000 km2 or roughly 10% of the yearly decline, but has been trending up by 6% per decade since 1979 (11% during summers). Given the condition of the ice I wonder  if  the cloudier stormier weather might cause a big change this year.
It's also worth noting that  export throught Nares, when the arches do not form, adds about 5% to the normal export so we can expect to see an additional 150 Km^2 going out through Nares this year.
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Re: The Nares Strait thread
« Reply #1178 on: June 23, 2017, 03:29:57 PM »
The addition of the recent paper by Andreas was very informative. I was relieved to see my speculation that this winter's ice arc in the Lincoln sea led to upwelling along the Greenland side of the Nares strait, and salinization of the water by means of the formation of new ice was consistent with his expert analysis.

The conclusion that we are observing a transition during which the last thick mullti-year ice leaves the arctic is disturbing but something I think we have been aware of for some time. Watching the thick land fast ice in the Lincoln sea break off the Greenland shore and pass down the strait is very disturbing because of the speed of the transition. In a few weeks huge thick blocks of ice have shattered into small fragments that will all pass Hans island before summer is over.

It's interesting to know that Hans island was part of a sedimentary basin that was once continuous to Svalbard but has since been rifted apart by the opening of the far north Atlantic and Arctic basins.

After the passage of hundreds of millions of years, the rifting and Pleistocene glaciation, Hans island is still a flat layered shallow sea floor unmetamorphosed carbonate sequence relatively undisturbed by the passage of so much time... an island of stability in a sea of change.

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Re: The Nares Strait thread
« Reply #1179 on: June 23, 2017, 04:23:58 PM »
HANS ISLAND:-
Totally off-topic, but will the Guv'nor kill a poem? This is a poem by Kay Kendall (January 1885) mocking Darwin's Origin of Species. I could not resist it.

The Lay of the Trilobite
A mountain’s giddy height I sought,
Because I could not find
Sufficient vague and mighty thought
To fill my mighty mind;
And as I wandered ill at ease,
There chanced upon my sight
A native of Silurian seas,
An ancient Trilobite.

So calm, so peacefully he lay,
I watched him even with tears:
I thought of Monads far away
In the forgotten years.
How wonderful it seemed and right,
The providential plan,
That he should be a Trilobite,
And I should be a Man!

And then, quite natural and free
Out of his rocky bed,
That Trilobite he spoke to me
And this is what he said:
‘I don’t know how the thing was done,
Although I cannot doubt it;
But Huxley – he if anyone
Can tell you all about it;

‘How all your faiths are ghosts and dreams,
How in the silent sea
Your ancestors were Monotremes –
Whatever these may be;
How you evolved your shining lights
Of wisdom and perfection
From Jelly-Fish and Trilobites
By Natural Selection.

‘You’ve Kant to make your brains go round,
Hegel you have to clear them,
You’ve Mr Browning to confound,
And Mr Punch to cheer them!
The native of an alien land
You call a man and brother,
And greet with hymn-book in one hand
And pistol in the other!

‘You’ve Politics to make you fight
As if you were possessed:
You’ve cannon and you’ve dynamite
To give the nations rest:
The side that makes the loudest din
Is surest to be right,
And oh, a pretty fix you’re in!’
Remarked the Trilobite.

‘But gentle, stupid, free from woe
I lived among my nation,
I didn’t care – I didn’t know
That I was a Crustacean.*
I didn’t grumble, didn’t steal,
I never took to rhyme:
Salt water was my frugal meal,
And carbonate of lime.’

Reluctantly I turned away,
No other word he said;
An ancient Trilobite, he lay
Within his rocky bed.
I did not answer him, for that
Would have annoyed my pride:
I merely bowed, and raised my hat,
But in my heart I cried: –

‘I wish our brains were not so good,
I wish our skulls were thicker,
I wish that Evolution could
Have stopped a little quicker;
For oh, it was a happy plight,
Of liberty and ease,
To be a simple Trilobite
In the Silurian seas!’
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

bairgon

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Re: The Nares Strait thread
« Reply #1180 on: June 24, 2017, 07:46:14 AM »
Some time back I asked this question:

I was also struck but what appear to be a line of fixed items across (Kane) basin. Are there small islands here?

Finally found the answer. They are grounded calved icebergs from the nearby glacier. The Sentinel playground shows them clearly here.

johnm33

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Re: The Nares Strait thread
« Reply #1181 on: June 24, 2017, 08:38:18 AM »
There appears to be a huge outflow of water beneath Humbolt

from https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim30d.gif
and the cracks are expanding and showing up on the Glacier not just the fast ice

best to click on bairgons link zoom in and look around, the cracks look ominous to me but maybe they're just streams.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1182 on: June 24, 2017, 02:44:22 PM »
Kane Basin is deep; there are no grounded icebergs in its middle.  See this post (from May 12) for bathymetry of Kane Basin.  There is a Kane Basin Gyre that keeps ice in its middle for several days.

What looks like ominous cracks in Humboldt Glacier (next to Kane Basin) are river beds (per attached screen print 'enlargement' from bairgon's Sentinel Playground link).
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

bairgon

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Re: The Nares Strait thread
« Reply #1183 on: June 24, 2017, 03:09:40 PM »
Kane Basin is deep; there are no grounded icebergs in its middle.

The bathymetry that you referenced only covers the south-western end of the basin.

Do you have another explanation for the static elements in this gif below?

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1184 on: June 24, 2017, 04:02:04 PM »
I do not have an explanation for those static white 'spots' on that animation.  (Your May 29 post shows them well.) They might be grounded ice, after all.

To further this exploration, I start with this May 22 post that draws from Wipneus's May 9 post (with enlarged GIF - with click) showing nothing grounded beyond the fast ice off Humboldt Glacier, at least where "Big Chuck" started.  The static white spots, however, may be a little bit north of where "Big Chunk" started.  [Alas, I have other things I have to do, so I'm stopping now.]
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

Phil.

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Re: The Nares Strait thread
« Reply #1185 on: June 24, 2017, 06:29:50 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

It is surprising how fast such a large floe can proceed down the channel.

Indeed, the fragment we were talking about is now about 55 miles south of Franklin Island.

Clenchie

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Re: The Nares Strait thread
« Reply #1186 on: June 24, 2017, 07:35:08 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

It is surprising how fast such a large floe can proceed down the channel.

Indeed, the fragment we were talking about is now about 55 miles south of Franklin Island.

The distinctive shape makes it easy to track.  Hopefully it is thick enough to remain intact and survive for another winter, currents allowing.
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Re: The Nares Strait thread
« Reply #1187 on: June 26, 2017, 02:48:56 AM »
CFS Alert, Nunavut @ Latitude 82.52° N | Longitude 62.28° W had a high today of 11C and sustained winds exceeding 50k/hr. Worldview June 25th image for the Lincoln Sea reflects the past two days winds and temperatures.

« Last Edit: June 26, 2017, 04:30:49 PM by Reggie »

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1188 on: June 26, 2017, 05:23:31 AM »
All the ice in the Lincoln Sea (including what is in the north end of Nares Strait [not off topic ::)] has been blown east- or northeastwasd between yesterday and today, per DMI Sentinel images, even the remaining (what I presume to be) thick ice just north of Greenland that had frozen in place for a few days.  Windytv's now-cast (screen print shown below) and forecasts of winds supports continued movement northwards for a few days.
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Phil.

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Re: The Nares Strait thread
« Reply #1189 on: June 26, 2017, 01:35:28 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

It is surprising how fast such a large floe can proceed down the channel.

Indeed, the fragment we were talking about is now about 55 miles south of Franklin Island.

The distinctive shape makes it easy to track.  Hopefully it is thick enough to remain intact and survive for another winter, currents allowing.

Now it's about 83 miles south of Franklin.

Clenchie

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Re: The Nares Strait thread
« Reply #1190 on: June 28, 2017, 01:25:00 PM »
Looks pretty intact, lucky floe!  By the way:  thanks Clenchie and Phil for watching.

(The floes actively approaching Nares Strait in the Lincoln Sea are all pretty small already.  The largest floes in the Lincoln Sea are hugging the Greenland coast and appear to be (temporarily) frozen in place.)

That floe has now made it unscathed past the two islands now. It seems that the ice near the entrance to the strait in the Lincoln sea has broken up into fairly small fragments compared with a week or so ago.

https://lance3.modaps.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2017173074500-2017173075000.250m.jpg

It is surprising how fast such a large floe can proceed down the channel.

Indeed, the fragment we were talking about is now about 55 miles south of Franklin Island.

The distinctive shape makes it easy to track.  Hopefully it is thick enough to remain intact and survive for another winter, currents allowing.

Now it's about 83 miles south of Franklin.

It has kept its distinctive bell shape and drifted into the centre of the channel.
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oren

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Re: The Nares Strait thread
« Reply #1191 on: June 28, 2017, 04:45:40 PM »
It has kept its distinctive bell shape and drifted into the centre of the channel.
For the sake of readability, may I suggest when quoting a chain of quotes, to edit and use just the last quote or the relevant part.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1192 on: June 28, 2017, 04:57:02 PM »
"It has kept its distinctive bell shape and drifted into the centre of the channel."

I've been wanting to call it the "Bell Floe" since before Hans Island, but I refrained myself as I enjoy using names derived from other's observations.  the Sentinel images show some curved texture that suggests it is a 3-D object and not a functionally flat floe.  Screen shots from DMI Sentinel & AQUA, both dated 2017-06-27
« Last Edit: June 28, 2017, 06:02:15 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1193 on: June 28, 2017, 05:57:33 PM »
The ice that had been blown away from the Elsmere Island coast (June 26 image) came back (June 27 image) (video screen shot from DMI-Sentinel)  Floes are again entering the Robeson Channel.
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Clenchie

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Re: The Nares Strait thread
« Reply #1194 on: June 28, 2017, 06:36:04 PM »
Quote
For the sake of readability, may I suggest when quoting a chain of quotes, to edit and use just the last quote or the relevant part.

Apologies, I thought the protocol was to leave a complete trail.  Will edit selectively in future.
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Clenchie

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Re: The Nares Strait thread
« Reply #1195 on: June 28, 2017, 06:44:45 PM »
Quote
I've been wanting to call it the "Bell Floe" since before Hans Island, but I refrained myself as I enjoy using names derived from other's observations.  the Sentinel images show some curved texture that suggests it is a 3-D object and not a functionally flat floe.  Screen shots from DMI Sentinel & AQUA, both dated 2017-06-27

It was either a bell or a Darth Vader mask so I plumped for brevity.  Interesting that you have discovered a curved texture on the North West sector of the floe.  Maybe we could get a 3d render at some point.  It looks to be only about 120km from Thule airbase - could be filmed from the air!

I have taken the liberty of juxtaposing two pictures that illustrate the rotation of the floe as it passes down the channel.  The first is from 19th June up by the Petermann glacier, the second is yesterday in the Kane Basin.

« Last Edit: June 28, 2017, 08:50:08 PM by Clenchie »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1196 on: June 28, 2017, 07:29:44 PM »
I also like the white fringe along the [would-be] 'open' edge of the bell on the Sentinel images.

Given the 'Bell Floe' is in Kane Basin and has wandered away from the Elsmere coast, it is liable to get caught up in the Kane Basin Gyre and remain there awhile.
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Phil.

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Re: The Nares Strait thread
« Reply #1197 on: June 30, 2017, 05:44:13 PM »
I also like the white fringe along the [would-be] 'open' edge of the bell on the Sentinel images.

Given the 'Bell Floe' is in Kane Basin and has wandered away from the Elsmere coast, it is liable to get caught up in the Kane Basin Gyre and remain there awhile.

It's actually been balanced on a cluster of floes stuck on the Greenland side for a couple of days at 79º30' N 70ºW.  Looks like a good puff of wind would shift it though.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1198 on: June 30, 2017, 06:41:32 PM »
"Balanced"?  Viewing successive EOSDIS Worldview images (from June 21), the Bell Floe has moved at least 15 km each day until yesterday (between June 28 and 29 [video below]) when one corner of it moved only a few km (northward).  With wind out of the north (per Windytv's now-cast, at least), this northward movement of the floe would be due to the gyre.  Smaller floes in the area aren't moving much.  (There are a few quite small floes (bergs?) near the lower right corner of this animation that don't move, including a "" shaped one.) [Bell Floe is about 15 km wide.]
« Last Edit: June 30, 2017, 06:54:21 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1199 on: June 30, 2017, 07:39:12 PM »
The (what I believe to be) oldest ice in the Lincoln Sea is now a cluster of large floes.  Sentinel images (via DMI) show this ice to be recently broken on June 5, moved southwestward on June 17 and moved (at least most of it) about half-way back on June 28.  Ice in the eastern part of Lincoln Sea continues (but not continuously so) to feed Nares Strait.  (3-date movie is from upper right part of area screen shot.)
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"