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Author Topic: The Nares Strait thread  (Read 703527 times)

uniquorn

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Re: The Nares Strait thread
« Reply #2450 on: December 29, 2020, 03:14:16 PM »
Regarding said "big block", now that the wind is blowing up the strait I noticed it is not behaving like its neighbors. It has the tendency to move away from the funnel more easily - could it be that its surface has some tall features that catch the wind in force?
Followed that MYI with the red dot over the last few months. In some ways the ice is its own worst enemy. The animation is best viewed at half speed.
Yesterday's polarview S1B

oren

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Re: The Nares Strait thread
« Reply #2451 on: December 29, 2020, 04:17:22 PM »
Thanks for this update uniquorn. Turns out Big Block did not really escape the funnel, but eventually was turned around and brought back during autumn, and now it's Big Rubble.

vox_mundi

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Re: The Nares Strait thread
« Reply #2452 on: January 06, 2021, 03:50:15 PM »
Ice Arches Holding Arctic's 'Last Ice Area' In Place Are At Risk, Researcher Says
https://phys.org/news/2021-01-ice-arches-arctic-area.html

...

G. W. K. Moore et al. Anomalous collapses of Nares Strait ice arches leads to enhanced export of Arctic sea ice, Nature Communications (2021).
https://www.nature.com/articles/s41467-020-20314-w


Sea ice concentration (%) along Nares Strait from AMSRE/2 satellite data during June.


Time series of duration (days) of ice stoppage along Nares Strait. During 2007 and 2019, indicated by the ‘o’, no arches formed.

... Recent work indicates that ice motion in the Last Ice Area, that includes the Lincoln Sea, is increasing at twice the rate as the entire Arctic Ocean14. In addition, a number of theoretical16,32 and observational8,17 studies have proposed that the stability of the Nares Strait ice arches decreases with thinning ice cover.

These results are consistent with those presented herein all of which provide additional evidence of the changing nature of the Arctic as we transition to a thinner more mobile ice pack. Results of this study also highlight that with continued Arctic warming, ice arch stability in Nares Strait as well as throughout the adjacent CAA will decrease resulting in more frequent transport of Arctic Ocean multi-year to southerly latitudes7, that will have negative implications for the maritime industry33,34 as well as impacting food security and other traditional activities for indigenous communities in the Arctic35.

The current configuration of the North Water Polynya, as a latent heat polynya, depends on the presence of the Nares Strait ice arches36 to restrict the southward flux of thick multi-year ice along Nares Strait. This allows the strong winds and ocean currents that occur in the vicinity of Smith Sound23,37 to advect thin ice away allowing the polynya to form. It follows that a weakening of the Nares Strait ice arches may impact the North Water Polynya leading to regional changes in primary and secondary production that will be felt throughout the entire food chain.
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gerontocrat

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Re: The Nares Strait thread
« Reply #2453 on: January 06, 2021, 04:36:04 PM »
The arch and the ice upstream from it nicely locked solid by the looks of it.
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vox_mundi

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Re: The Nares Strait thread
« Reply #2454 on: January 06, 2021, 04:46:25 PM »
Like the article says; 5 months till June.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

gerontocrat

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Re: The Nares Strait thread
« Reply #2455 on: January 10, 2021, 09:48:56 PM »
BBC science article @ https://www.bbc.co.uk/news/science-environment-55594585 telling us of that which ASIF members are already cognisant.

Climate change: Weakened 'ice arches' speed loss of Arctic floes


Quote
....what Prof Moore's and colleagues' satellite research has shown is that these structures are becoming less reliable barriers.
They are forming for shorter periods of time, and the amount of frozen material allowed to pass through the strait is therefore increasing as a consequence.

"We have about 20 years of data, and over that time the duration of these arches is definitely getting shorter," Prof Moore explained.

"We show that the average duration of these arches is decreasing by about a week every year. They used to last for 250-200 days and now they last for 150-100 days. And then as far as the transport goes - in the late 1990s to early 2000s, we were losing about 42,000 sq km of ice every year through Nares Strait; and now it's doubled: we're losing 86,000 sq km."

Prof Moore says we need to hang on to the oldest ice in the Arctic for as long as possible.

If the world manages to implement the ambition of the Paris climate accord and global warming can be curtailed and reversed, then it's the thickest ice retained along the top of Canada and Greenland that will "seed" the rebound in the frozen floes.

The area of oldest, thickest ice, he adds, is also going to be an important refuge for those species that depend on the floating floes for their way of life - the polar bears, walruses and seals.

"My concern is that this last ice area may not last for as long as we think it will. This is ice that is five, six, even 10 years old; so if we lose it, it will take a long time to replenish even if we do eventually manage to cool the planet."

Prof Moore and colleagues have published their latest research in the journal Nature Communications***.

***   https://www.nature.com/articles/s41467-020-20314-w

Open access - some super stuff in it.





"Para a Causa do Povo a Luta Continua!"
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Niall Dollard

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Re: The Nares Strait thread
« Reply #2456 on: January 11, 2021, 01:12:33 AM »
Yes an interesting read, Gero. (Vox mundi has also posted a link to this Nature article early in this thread).

I do have one gripe.It is an issue that I have seen mentioned on the ASIF several times before - which is how old these papers are by the time they get published.

This paper on Nature Communications was published 4th Jan 2021 and yet has no mention of 2020. The Nares arches were done and dusted by July 2020. 7 months later and no inclusion of the 2020 data. 2017 and 2019 were bad years for arch formation. In 2020 the arch held for approx 200 days, which is more like the longevity arches of old. It is quite likely the arch in 2021 will last over 200 days also.

I have already put a calculation on arch longevity (2007-2020), within the Nares Strait, in post 2448 of this thread. Because of bad years 2017 and 2019 the 5 year average has dropped considerably but 2020 and 2021 will make it rise again (a little).

Like for so much of the Arctic, time is running out for the arches in the Nares. I was surprised that for both 2020 and now 2021, arch formation has begun relatively early. Whilst the Nature Comms article is a good read. It is not up to date.   

interstitial

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Re: The Nares Strait thread
« Reply #2457 on: January 11, 2021, 02:10:35 PM »
Yes an interesting read, Gero. (Vox mundi has also posted a link to this Nature article early in this thread).

I do have one gripe.It is an issue that I have seen mentioned on the ASIF several times before - which is how old these papers are by the time they get published.

This paper on Nature Communications was published 4th Jan 2021 and yet has no mention of 2020. The Nares arches were done and dusted by July 2020. 7 months later and no inclusion of the 2020 data. 2017 and 2019 were bad years for arch formation. In 2020 the arch held for approx 200 days, which is more like the longevity arches of old. It is quite likely the arch in 2021 will last over 200 days also.

I have already put a calculation on arch longevity (2007-2020), within the Nares Strait, in post 2448 of this thread. Because of bad years 2017 and 2019 the 5 year average has dropped considerably but 2020 and 2021 will make it rise again (a little).

Like for so much of the Arctic, time is running out for the arches in the Nares. I was surprised that for both 2020 and now 2021, arch formation has begun relatively early. Whilst the Nature Comms article is a good read. It is not up to date.   

It takes time to gather the data. It takes time to write and polish. If you go back and add more data you have to rewrite it and polish again. Then you submit It takes time for an initial judgement by the publication. It takes time for reviewers (they are volunteers so reviewing is not their most pressing task). If their are any corrections or clarifications those take time. Their are usually at least some clarifications. It takes time for publication to give final approval. After final approval it has to be determined when to publish it. It doesn't always go into the next issue. Depending on the journal between first submission and publication can take half a year or more. The time it takes can vary greatly and on occasion things languish. These publications may or may not have full time staff.

uniquorn

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Re: The Nares Strait thread
« Reply #2458 on: January 11, 2021, 08:41:13 PM »
Still some tidal movement in the Robeson Channel, https://go.nasa.gov/3siankW  jan2-10
rammb JPSS, band I4, jan2-11

Niall Dollard

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Re: The Nares Strait thread
« Reply #2459 on: January 27, 2021, 09:07:12 PM »
A sliver breaks off the Ellesmere side. It looks like only recent ice.

Alumril

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Re: The Nares Strait thread
« Reply #2460 on: February 24, 2021, 09:28:13 PM »


G. W. K. Moore et al. Anomalous collapses of Nares Strait ice arches leads to enhanced export of Arctic sea ice, Nature Communications (2021).
https://www.nature.com/articles/s41467-020-20314-w


Presentation by Kent Moore now available on youtube covering this paper.