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jai mitchell

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Beaufort Gyre Reversal and a Return to 1960's Level SIE
« on: December 13, 2017, 05:18:30 PM »
This interesting presentation about the potential for a long-term reversal of the Beaufort Gyre under a warming Arctic is very provocative.  While being unable to hear the actual presentation that these slides are associated with (link: https://www.us-ocb.org/wp-content/uploads/sites/43/2017/03/OCB-meeting-2014-Beaufort_Gyre_Dynamics_and_implications_for_North_Atlantic-Arctic-exchange-1_189964.pdf ) the image below is almost magical in its projections. 

Fuller discussion of this can be found here.  http://e360.yale.edu/features/how-a-wayward-arctic-current-could-cool-the-climate-in-europe

Wouldn't that be wonderful???
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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #1 on: December 13, 2017, 07:31:40 PM »
jai,

Since your linked PowerPoint presentation was release in 2014, the Beaufort Gyre (BG) has continued to accumulate a greater volume of freshwater, and if the linked reference is correct, then ice mass loss from the GIS is most likely to blame for this atypically large accumulation of freshwater in the BG.  Furthermore, I suspect that as the Jakobshavn Glacier's grounding line is about to recede down a portion of negative sloping bed, I suspect that until about 2028 ice mass loss from the GIS will be sufficient to keep the BG accumulating more and more freshwater.  This makes me concerned that when the BG eventually reverses its rotation after 2028, the freshwater hosing of the North Atlantic will induce a temporary slowing of the AMOC; which due to bipolar seesaw could trigger the WAIS to begin its main phase of collapse by 2040.

Best,
ASLR

Andrey Proshutinsky, Dmitry Dukhovskoy, Mary-Louise Timmermans, Richard Krishfield, Jonathan L. Bamber (2015), "Arctic circulation regimes", Philosophical Transactions of the Royal Society A, DOI: 10.1098/rsta.2014.0160

http://rsta.royalsocietypublishing.org/content/373/2052/20140160

Abstract: "Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability."
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jai mitchell

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #2 on: December 13, 2017, 07:46:43 PM »
With regard to the "arctic cooling of the 1970's' in your last graphic, I suggest the following correction (not that it was your error).

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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #3 on: December 13, 2017, 08:05:16 PM »
With regard to the "arctic cooling of the 1970's' in your last graphic, I suggest the following correction (not that it was your error).

jai,

I think that the graphic that you cite is indicating changes in surface salinity of the North Atlantic (due to freshwater hosing from the Beaufort Gyre), not changes in SAT for the Arctic.

Best,
ASLR
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Pmt111500

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #4 on: December 13, 2017, 09:14:14 PM »
Looks like one which could be published on Apr-1st.

AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #5 on: December 13, 2017, 09:31:55 PM »
Looks like one which could be published on Apr-1st.

The increasing freshwater accumulation with the Beaufort Gyre, BG, is all too real (& is measurable as indicated by the linked report), and that accumulation of freshwater will advect to the North Atlantic sooner, or later:

https://www.polartrec.com/expeditions/co2-and-ph-studies-of-the-arctic-ocean/journals/2017-10-01

Extract: "During the rapid increase in BG freshwater content over 2005-2007 sea-ice meltwater increased by 2.7 m in the central BG region and low-salinity water from the Mackenzie River was advected to the southern BG region. After 2007 the major contributors to the freshwater increase of the BG freshwater reservoir have been Mackenzie river, fresh water from the Pacific Ocean, and from ice melt and precipitation minus evaporation."
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Neven

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #6 on: December 13, 2017, 09:39:00 PM »
Wouldn't that be wonderful???

It would be wonderful if at the same time the world stopped warming, or at least CO2 concentrations would be going down. But such a huge change, while at the same time the entire system sucks up more and more energy, almost guarantees unforeseen consequences to go with it.

I had already had a tab open with that Yale E360 article, and your opening this thread spurred me to read it. Right away after reading the opening sentence...

Quote
For millennia, the Beaufort Gyre — a massive wind-driven current in the Arctic Ocean — has been regulating climate and sea ice formation at the top of the world.

I'm like: And what is driving these winds that are driving the Beaufort Gyre, and isn't this the thing that is actually regulating the mentioned stuff? 'For years my steering wheel has brought me to places I needed to go'.  ;)

But there's something else I don't get. In the article it says:

Quote
During the second half of the 20th century — and, most likely, earlier — the gyre adhered to a cyclical pattern in which it would shift gears every five to seven years and temporarily spin in a counter-clockwise direction, expelling ice and freshwater into the eastern Arctic Ocean and the North Atlantic. But for more than a dozen years, this carousel of ice and, increasingly, freshwater has been spinning faster in its usual clockwise direction, all the while collecting more and more freshwater from three sources: melting sea ice, huge volumes of runoff flowing into the Arctic Ocean from Russian and North American rivers, and the relatively fresh water streaming in from the Bering Sea.

This suggests that the BG is either turning clockwise or counter-clockwise for long stretches of time. But my perception is that it is constantly switching. Note, however, that I do most of my perceiving during the summer. Maybe this is about autumn and winter. But the article suggests, several times, that the BG is spinning like crazy, but can suddenly reverse. I'm reading the article for the second time now, and it somewhat confuses me.

I'll now go read the presentation you link to, jai.

BTW In the Yale E360 article there is mention and a couple of quotes from Alek Petty. Back in 2016 he wrote a guest blog for the ASIB about the Beaufort Gyre and fresh water. I'm re-reading that too.
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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #7 on: December 13, 2017, 11:00:15 PM »
Due to the importance of the coming freshwater flux from the Beaufort Gyre in to the North Atlantic (particularly w.r.t. Hansen's freshwater hosing-climate feedback mechanism), I provide the following selected information about the 2018 Ocean Science Meeting Session entitled: " HE003: Freshwater Fluxes in the Arctic Ocean – North Atlantic Climate System"

https://agu.confex.com/agu/os18/preliminaryview.cgi/Session23525

Summary: "Oceanic and sea ice freshwater fluxes in the Arctic Ocean – North Atlantic climate system impact thermohaline and convective processes, with far-reaching influence on climate. Increased freshwater fluxes to the Arctic Ocean along with the wind-driven anticyclonic circulation have resulted in growing freshwater content in the Beaufort Gyre. There is no observational evidence of significant changes in freshwater fluxes between the Arctic Ocean and the North Atlantic. Yet freshwater flux from the Greenland Ice Sheet is clearly increasing and may be impacting thermohaline processes in the North Atlantic. It is a priority to discern the driving mechanisms, the role and consequences of changing freshwater fluxes into the Arctic Ocean and North Atlantic. This session solicits papers addressing issues related to oceanic freshwater fluxes (liquid and sea ice) in the Arctic Ocean – North Atlantic climate system. Possible topics include: Propagation mechanisms, pathways and time scales of fresh water anomalies; residence time of fresh water; impacts of changes to the cryosphere; the role of freshwater in the future Arctic climate; the sensitivity of thermohaline circulation to freshwater fluxes; the relationship between sea ice and freshwater content in the ocean; and, biological and environmental consequences of increased freshwater fluxes."

Laura de Steur, et al (2018), "Increased freshwater export though Fram Strait contributes to freshening in the North Atlantic (301769)"

Andrey Yu Proshutinsky, Richard A Krishfield, Mary-Louise Timmermans and William James Williams (2018), "Causes and Consequences of Beaufort Gyre Freshwater Content Changes in 2003-2017 (303087)"

Dmitry S Dukhovskoy (2018), "Freshwater pathways in the Arctic Ocean and northern North Atlantic from a numerical experiment with passive tracers (304003)"

Oleg Saenko et al (2018), "Response of the North Atlantic Dynamic Sea Level and Circulation to Greenland Meltwater under Present and Projected Climates (304135)"

Elizabeth Douglass (2018), "Impact of Freshwater from Arctic Rivers in a High-Resolution Model (305887)"

Subrahmanyam Bulusu (2018), "Recent changes in the Arctic Circulation and Freshwater Fluxes (Invited) (306593)"

Freshwater fluxes between the Arctic Ocean and the North Atlantic from water stable isotopes: study of coastal currents and interior of the subpolar gyre. (308866)

A new record of North Atlantic sea surface salinity and temperature from 1896–2015 reveals modes of variability and long–term trends (309308)
Andrew Ronald Friedman1, Gilles P Reverdin2, Myriam Khodri1 and Guillaume Gastineau1, (1)Sorbonne-Universités, LOCEAN, CNRS/IRD/UPMC/MNHN, Paris, France, (2)LOCEAN - Sorbonne Universités - UPMC/CNRS/IRD/MNHN, Paris, France
Marion Benetti et al. (2018), "Observed Greenland Glacial Melt Water Distribution in the Greenland Sea (310757)"

Caroline A Katsman et al (2018), "Impacts of Arctic precipitation changes on the downwelling limb of the Atlantic Meridional Overturning Circulation (310762)

Heather Regan (2018), "Investigating the Spatial and Temporal Variability of the Beaufort Gyre from Satellite Observations (311439)"
 
Cristian Florindo-Lopez  et al (2018), "Observational Evidence of Multi-Decadal Changes in Arctic Freshwater Transport to the Subpolar North Atlantic (313117)"

Nathan Grivault (2018), "Frequency of Volume and Freshwater Events Leaving the Arctic Ocean: A Numerical Study. (314363)"

Gilles Garric (2018), "Dependencies of Arctic Freshwater Content and Transport to Surface Atmospheric Conditions (316214)"

Per Pemberton et al. (2018), "The response of the Arctic Ocean to freshwater and wind perturbations (317179)"

Helen Johnson et al (2018), "Response of Arctic Ocean Freshwater Content to Large Scale Atmospheric Forcing Changes in a Coupled Climate Model  (317606)"

Rory Laiho et al. (2018), "Internal Variability in the Arctic Freshwater Budget as Simulated by the CESM Large Ensemble (321495)"

Clark William Pennelly et al. (2018), "Numerical modeling in the northern Atlantic: Labrador Sea freshwater. (321605)"

Marilena Oltmanns et al (2018), "Rapid North Atlantic Cooling Induced by Fresh, Cold and Shallow Mixed Layers in the Subpolar Gyre (321700)"

Jiayan Yang, (2018), "A process-modeling study of the Arctic-Atlantic Ocean exchanges and their role in the Arctic Ocean freshwater export (322447)"
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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #8 on: December 13, 2017, 11:07:14 PM »
I'm like: And what is driving these winds that are driving the Beaufort Gyre, and isn't this the thing that is actually regulating the mentioned stuff? 'For years my steering wheel has brought me to places I needed to go'.  ;)

But there's something else I don't get. In the article it says:

Quote
During the second half of the 20th century — and, most likely, earlier — the gyre adhered to a cyclical pattern in which it would shift gears every five to seven years and temporarily spin in a counter-clockwise direction, expelling ice and freshwater into the eastern Arctic Ocean and the North Atlantic. But for more than a dozen years, this carousel of ice and, increasingly, freshwater has been spinning faster in its usual clockwise direction, all the while collecting more and more freshwater from three sources: melting sea ice, huge volumes of runoff flowing into the Arctic Ocean from Russian and North American rivers, and the relatively fresh water streaming in from the Bering Sea.

This suggests that the BG is either turning clockwise or counter-clockwise for long stretches of time. But my perception is that it is constantly switching. Note, however, that I do most of my perceiving during the summer. Maybe this is about autumn and winter. But the article suggests, several times, that the BG is spinning like crazy, but can suddenly reverse. I'm reading the article for the second time now, and it somewhat confuses me.

One can't just watch the sea ice movement patterns to determine the direction of circulation of the BG as most is its mass is associated with deeper water currents below the surface.
« Last Edit: December 14, 2017, 03:58:32 PM by AbruptSLR »
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Pmt111500

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #9 on: December 14, 2017, 05:06:43 AM »
Hmm, so this would be more about Arctic-North Atlantic -relations? This could be a soft landing back to readinh scientific articles that I've missed in past 6 months (or a year or so, who cares, since the rigged electionä). I too prefer models of static universe rather than some heat death m8dels. Let bifurcation point = now, let bifurcation point-1 = one year before measurements began, predict the future behavior of the function.

But ok, maybe there is something to it ( haven't read it yet ).
« Last Edit: December 14, 2017, 05:59:16 AM by Pmt111500 »

Bruce Steele

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #10 on: December 14, 2017, 07:08:39 AM »
Since the 2012 GAC I have been watching ITP buoys. They have shown a deepening of fresh water in the Pacific warm water layer yes but when did the BG reverse?  Slow down yes , on occasion, but when did buoys move from the Beaufort off Barrow or the Mackenzie eastward ( counter clockwise) and exit the Arctic via the Fram ? I must have missed something but the ITP buoy data is all cataloged and available for review. Where is the evidence of a reversal ?  Not saying it never happens but damn I must have missed it.
 I would think the Garlic press in 2016 was evidence of a large freshwater exit but it wasn't the Fram
and it wasn't a reversal.

Pmt111500

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #11 on: December 14, 2017, 07:45:16 AM »
The reversals have been quite short in duration, week or two at times. I don't remember if there's been longer durations nor if there's been any seasonality or changes in seasonality. I do remember though, they've not happened every year or at least there's no solid data of these, so maybe they've become more frequent in some datasets.

AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #12 on: December 14, 2017, 04:11:46 PM »
If one wants to live in a small enough bubble (of information) then one can come to any conclusion that one is comfortable with.  However, global circulation models, GCMs, cannot yet capture all of the global feedback mechanism of the Earth Systems, so in this post I discuss how a freshwater release from the BG into the North Atlantic can cause Arctic Amplification due to the bipolar seesaw, Agulhas Leakage and atmospheric Rossby waves advecting energy from the tropical ocean directly to the Arctic.

The first linked Marino & Zahn (2015) reference (and first attached image) shows how a cooling of the North Atlantic can cause warming around Antarctica and an increase of Agulhas Leakage which can interact with the AMOC to strengthen Arctic Amplification and the bipolar seesaw:

Gianluca Marino and Rainer Zahn (January 2015), "The Agulhas Leakage: the missing link in the interhemispheric climate seesaw?", Past Global Changes Magazine, SCIENCE HIGHLIGHTS: Glacial terminations and interglacials

http://www.pages-igbp.org/download/docs/magazine/2015-1/PAGESmagazine_2015(1)_22-23_Marino.pdf

&

With continued global warming one can expect more Agulhas leakage (see the second image); which per the second linked reference means that one can expect the AMOC to continue slowing; which should work synergistically with Hansen's ice-climate feedback, particularly if the WAIS collapses in coming decades:

Kathryn A. Kelly, Kyla Drushka, LuAnne Thompson, Dewi Le Bars & Elaine L. McDonagh (25 July 2016), "Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports", Geophysical Research Letters, DOI: 10.1002/2016GL069789

http://onlinelibrary.wiley.com/doi/10.1002/2016GL069789/abstract

And for those who have trouble envisioning how increased Agulhas Leakage triggered by a cooling of the North Atlantic could lead to Arctic Amplification associated with the transfer of energy through the atmosphere from the Tropical Atlantic directly to the Arctic, I provide the third attached image & associate caption from the third linked reference, which show how this occurs due to Rossby Waves:

Merryfield, W. J., F. J. Doblas-Reyes, L. Ferranti, J.-H. Jeong, Y. J. Orsolini, R. I. Saurral, A. A. Scaife, M. A. Tolstykh, and M. Rixen (2017), Advancing climate forecasting, Eos, 98, https://doi.org/10.1029/2017EO086891

https://eos.org/project-updates/advancing-climate-forecasting?utm_source=eos&utm_medium=email&utm_campaign=EosBuzz120117

Caption: "Fig. 1. Averaged atmospheric response during winter in the Northern Hemisphere to recent El Niño events, connecting atmospheric changes in the tropics with those at latitudes farther north and south. Dots represent approximate pathways of planetary waves [after Scaife et al., 2017]. Colors show associated changes in sea level pressure (SLP) in hectopascals (hPa), indicative of atmospheric circulation changes. In the Northern Hemisphere, changes are clockwise for positive contours, represented by warm colors, and counterclockwise for negative contours, represented by cool colors; these directions are opposite in the Southern Hemisphere. Credit: Adam Scaife"
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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #13 on: December 14, 2017, 07:46:34 PM »
For those who want further evidence of the bipolar seesaw mechanism, I provide the following linked reference (& associated linked article), that provides details including how atmospheric Rossby wave trains can relatively rapidly activate the bipolar seesaw mechanism (presumably fast enough so that a cooling of the North Atlantic [due a freshwater drainage event from the BG, circa 2030 to 2035] could trigger a main phase collapse of the WAIS by 2040, which would then tip the seesaw in the other direction resulting in increased Artic Amplification:

Turney et al (2017), "Rapid global ocean-atmosphere response to Southern Ocean freshening during the last glacial", Nature Communications, doi:10.1038/s41467-017-00577-6

https://www.nature.com/articles/s41467-017-00577-6

Abstract: "Contrasting Greenland and Antarctic temperatures during the last glacial period (115,000 to 11,650 years ago) are thought to have been driven by imbalances in the rates of formation of North Atlantic and Antarctic Deep Water (the ‘bipolar seesaw’). Here we exploit a bidecadally resolved 14C data set obtained from New Zealand kauri (Agathis australis) to undertake high-precision alignment of key climate data sets spanning iceberg-rafted debris event Heinrich 3 and Greenland Interstadial (GI) 5.1 in the North Atlantic (~30,400 to 28,400 years ago). We observe no divergence between the kauri and Atlantic marine sediment 14C data sets, implying limited changes in deep water formation. However, a Southern Ocean (Atlantic-sector) iceberg rafted debris event appears to have occurred synchronously with GI-5.1 warming and decreased precipitation over the western equatorial Pacific and Atlantic. An ensemble of transient meltwater simulations shows that Antarctic-sourced salinity anomalies can generate climate changes that are propagated globally via an atmospheric Rossby wave train."

&

Title: "How Antarctic ice melt can be a tipping point for the planet's climate"

https://phys.org/news/2017-09-antarctic-ice-planet-climate.html

Extract: "Twenty-five of these major so-called Dansgaard–Oeschger (D-O) warming events have been identified. These abrupt swings in temperature happened too quickly to have been caused by Earth's slowly changing orbit around the Sun. Fascinatingly, when ice cores from Antarctica are compared with those from Greenland, we see a "seesaw" relationship: when it warms in the north, the south cools, and vice versa."
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AbruptSLR

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #14 on: December 15, 2017, 12:16:37 AM »
Agulhas Leakage (see Reply #12) warms the Tropical Atlantic and thus could contribute to the enhanced evaporation in this region, which per the attached image and linked reference, about interglacial periods, can trigger abrupt changes in the AMOC that can lead to warming of the Arctic:

Xu Zhang et al. (2017), "Abrupt North Atlantic circulation changes in response to gradual CO2 forcing in a glacial climate state", Nature Geoscience, doi:10.1038/ngeo2974

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2974.html

Abstract: "Glacial climate is marked by abrupt, millennial-scale climate changes known as Dansgaard–Oeschger cycles. The most pronounced stadial coolings, Heinrich events, are associated with massive iceberg discharges to the North Atlantic. These events have been linked to variations in the strength of the Atlantic meridional overturning circulation. However, the factors that lead to abrupt transitions between strong and weak circulation regimes remain unclear. Here we show that, in a fully coupled atmosphere–ocean model, gradual changes in atmospheric CO2 concentrations can trigger abrupt climate changes, associated with a regime of bi-stability of the Atlantic meridional overturning circulation under intermediate glacial conditions. We find that changes in atmospheric CO2 concentrations alter the transport of atmospheric moisture across Central America, which modulates the freshwater budget of the North Atlantic and hence deep-water formation. In our simulations, a change in atmospheric CO2 levels of about 15 ppmv—comparable to variations during Dansgaard–Oeschger cycles containing Heinrich events—is sufficient to cause transitions between a weak stadial and a strong interstadial circulation mode. Because changes in the Atlantic meridional overturning circulation are thought to alter atmospheric CO2 levels, we infer that atmospheric CO2 may serve as a negative feedback to transitions between strong and weak circulation modes."

See also the associated linked article entitled: "Scientists throw light on mysterious ice age temperature jumps"

https://phys.org/news/2017-06-scientists-mysterious-ice-age-temperature.html

Extract: "In a new study published today, the researchers show that rising levels of CO2 could have reached a tipping point during these glacial periods, triggering a series of chain events that caused temperatures to rise abruptly.

The findings, which have been published in the journal Nature Geoscience, add to mounting evidence suggesting that gradual changes such as a rising CO2 levels can lead to sudden surprises in our climate, which can be triggered when a certain threshold is crossed.

Previous studies have shown that an essential part of the natural variability of our climate during glacial times is the repeated occurrence of abrupt climate transitions, known as Dansgaard-Oeschger events.

These events are characterized by drastic temperature changes of up to 15°C within a few decades in the high latitudes of the Northern Hemisphere. This was the case during the last glacial period around 100,000 to 20,000 years ago.

It is commonly believed that this was a result of sudden floods of freshwater across the North Atlantic, perhaps as a consequence of melting icebergs.

Co-author of the study Professor Stephen Barker, from Cardiff University's School of Earth and Ocean Sciences, said: "Our results offer an alternative explanation to this phenomenon and show that a gradual rise of CO2 within the atmosphere can hit a tipping point, triggering abrupt temperature shifts that drastically affect the climate across the Northern Hemisphere in a relatively short space of time.

"These findings add to mounting evidence suggesting that there are sweet spots or 'windows of opportunity' within climate space where so-called boundary conditions, such as the level of atmospheric CO2 or the size of continental ice sheets, make abrupt change more likely to occur. Of course, our study looks back in time and the future will be a very different place in terms of ice sheets and CO2 but it remains to be seen whether or not Earth's climate becomes more or less stable as we move forward from here".

Using climate models to understand the physical processes that were at play during the glacial periods, the team were able to show that a gradual rise in CO2 strengthened the trade winds across Central America by inducing an El Nino-like warming pattern with stronger warming in the East Pacific than the Western Atlantic.

As a result there was an increase in moisture transport out of the Atlantic, which effectively increased the salinity and density, of the ocean surfaces, leading to an abrupt increase in circulation strength and temperature rise.

"This does not necessarily mean that a similar response would happen in the future with increasing CO2 levels, since the boundary conditions are different from the ice age," added by Professor Gerrit Lohmann, leader of the Paleoclimate Dynamics group at the Alfred Wegener Institute.

"Nevertheless, our study shows that climate models have the ability of simulating abrupt changes by gradual forcing as seen in paleoclimate data.""
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Bruce Steele

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #15 on: July 14, 2019, 10:35:05 PM »
It has been a while since the topic of a gyre reversal has been discussed. Although the Beaufort Gyre used to reverse direction and spin counterclockwise every 5 to 7 years it has now been 21 years since a reversal has occurred. The fresh water in the Gyre has continued to increase as has the Pacific Warm Water in the Beaufort. I was looking for new studies but I didn't find any. The WHOI Beaufort Gyre webpage has a reference to " Arctic Sea Ice Forum "  and ASLR has as good a summary as I can find. 

https://www.whoi.edu/website/beaufortgyre/home

So there is a long range , one week , projection of a strong low pressure setting up over the Gyre. I would think one of these years a reversal will happen . If there was a concurrent Garlic press set-up ...
Anyhow it would be something different than the Arctic we are used to watch melt and freeze.

Freegrass

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #16 on: July 26, 2020, 11:42:37 AM »
I've been wondering what's going on with the Beaufort Gyre this year. Is my perception correct that it isn't spinning like it was before?

I found this thread about the BG and thought it may be a good place to discuss this.

I also found this article from February 7, 2020 that helped me understand the gyre a little better, but I'm very curious what the specialists have to say about the current situation.

Arctic Ice Melt Is Changing Ocean Currents

https://www.nasa.gov/feature/jpl/arctic-ice-melt-is-changing-ocean-currents

A major ocean current in the Arctic is faster and more turbulent as a result of rapid sea ice melt, a new study from NASA shows. The current is part of a delicate Arctic environment that is now flooded with fresh water, an effect of human-caused climate change.

Using 12 years of satellite data, scientists have measured how this circular current, called the Beaufort Gyre, has precariously balanced an influx of unprecedented amounts of cold, fresh water — a change that could alter the currents in the Atlantic Ocean and cool the climate of Western Europe.

The Beaufort Gyre keeps the polar environment in equilibrium by storing fresh water near the surface of the ocean. Wind blows the gyre in a clockwise direction around the western Arctic Ocean, north of Canada and Alaska, where it naturally collects fresh water from glacial melt, river runoff and precipitation. This fresh water is important in the Arctic in part because it floats above the warmer, salty water and helps to protect the sea ice from melting, which in turn helps regulate Earth's climate. The gyre then slowly releases this fresh water into the Atlantic Ocean over a period of decades, allowing the Atlantic Ocean currents to carry it away in small amounts.

But the since the 1990s, the gyre has accumulated a large amount of fresh water — 1,920 cubic miles (8,000 cubic kilometers) — or almost twice the volume of Lake Michigan. The new study, published in Nature Communications, found that the cause of this gain in freshwater concentration is the loss of sea ice in summer and autumn. This decades-long decline of the Arctic's summertime sea ice cover has left the Beaufort Gyre more exposed to the wind, which spins the gyre faster and traps the fresh water in its current.

Persistent westerly winds have also dragged the current in one direction for over 20 years, increasing the speed and size of the clockwise current and preventing the fresh water from leaving the Arctic Ocean. This decades-long western wind is unusual for the region, where previously, the winds changed direction every five to seven years.

Scientists have been keeping an eye on the Beaufort Gyre in case the wind changes direction again. If the direction were to change, the wind would reverse the current, pulling it counterclockwise and releasing the water it has accumulated all at once.

"If the Beaufort Gyre were to release the excess fresh water into the Atlantic Ocean, it could potentially slow down its circulation.
And that would have hemisphere-wide implications for the climate, especially in Western Europe," said Tom Armitage, lead author of the study and polar scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.

Fresh water released from the Arctic Ocean to the North Atlantic can change the density of surface waters. Normally, water from the Arctic loses heat and moisture to the atmosphere and sinks to the bottom of the ocean, where it drives water from the north Atlantic Ocean down to the tropics like a conveyor belt.

This important current is called the Atlantic Meridional Overturning Circulation and helps regulate the planet's climate by carrying heat from the tropically-warmed water to northern latitudes like Europe and North America. If slowed enough, it could negatively impact marine life and the communities that depend it.

"We don't expect a shutting down of the Gulf Stream, but we do expect impacts. That's why we're monitoring the Beaufort Gyre so closely," said Alek Petty, a co-author on the paper and polar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The study also found that, although the Beaufort Gyre is out of balance because of the added energy from the wind, the current expels that excess energy by forming small, circular eddies of water. While the increased turbulence has helped keep the system balanced, it has the potential to lead to further ice melt because it mixes layers of cold, fresh water with relatively warm, salt water below. The melting ice could, in turn, lead to changes in how nutrients and organic material in the ocean are mixed, significantly affecting the food chain and wildlife in the Arctic. The results reveal a delicate balance between wind and ocean as the sea ice pack recedes under climate change.

"What this study is showing is that the loss of sea ice has really important impacts on our climate system that we're only just discovering," said Petty.

Rexana Vizza / Matthew Segal
Jet Propulsion Laboratory, Pasadena, Calif.
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Bruce Steele

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #17 on: July 26, 2020, 03:25:40 PM »
Freegrass, The two ITP buoys with working temp/salinity contours both show there has been a decrease in the surface fresh water layer near the center of the Beaufort gyre. This year compared to ITP buoy runs from completed ITP missions show that about ten to fifteen meters of fresh water has exited the gyre. I talked about it on the “what the buoys are telling us” page. I put some completed mission runs you can compare with.
 Bbr linked a comparison of surface fresh water 2019 and 2020 for the arctic and it showed more fresh surface water in the channels of the CAA but another comparison of fresh water at 35 meters posted by
Uniquorn didn’t show any changes in the CAA. So where the fresh water may have gone is still a question but eventually it will make a path to the Atlantic what ever route it has taken.
 

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #18 on: July 26, 2020, 05:44:04 PM »
Thank you Bruce. I found the thread and just read some of it. It's very technical, but from what I understand is that there's still a lot of unknowns.

That's the thing with amateur newbies like me, we want simple answers to difficult questions, but I guess that's not how the arctic works. So I'm gonna stick to what I know a little about and leave the more difficult stuff up to you guys. I'm sure that when a simple answer presents itself that it will be shared.

One thing I'm still dying to know more about is what's happening to the current in the ESS. Is there a discussion about that somewhere? To me it seems like the Bering strait current is going into the ESS instead of the beaufort. Is that normal? Blum said this could be due to the wind, but I find that hard to believe, because at depth the same thing seems to be happening as well.

Could the beaufort gyre have something to do with this? Or am I asking another way to difficult question?

Thanks again for the reply!
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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #19 on: July 26, 2020, 06:47:02 PM »
Now is really a lot of ice in the Beaufort Sea. Possibe ice really will live to see next winter?

https://twitter.com/AlaskaWx/status/1285990099381977088

Quote
The Beaufort Sea is the only #Arctic region where #seaice extent is close to the @NSIDC data long term average. In part tied to the same wx pattern supporting the Siberian warmth. For the Beaufort, anomalous north winds so far this summer. Some multi-year ice also present. akwx



Only in 2018 there were more ice here in last five years.

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #20 on: July 26, 2020, 09:36:42 PM »
Freegrass, I think you are asking the right questions and Pacific inflow through the Bering Strait is something I have an interest in also. Salinity and temperature affect density of different water masses.
Pacific inflow is more dense than the freshwater surface layer it meets as it moves North and through channels( canyons )on either side of Herald and Hanna Shoals. With satellites we can see what is happening on the surface but we can’t see the pacific water as it dives under the 35-50 meters of surface fresh water.
 There is Atlantic water that moves east along the Siberian Coast and it has mixed with large Siberian river flow. It does mix with some of the Pacific Water as it moves north out across shelf and the Chukchi plateau.
But both Pacific and Atlantic waters for the most part end up in the halocline that starts at the bottom of the surface fresh water layer. I would like to understand where and how the halocline leaves the Beaufort.


http://psc.apl.washington.edu/HLD/Chukchi/Chukchi.html

I wish I read the reversal of the Siberian coastal current tread before posting. I defer to Fishoutofwater.
 
« Last Edit: July 26, 2020, 10:56:32 PM by Bruce Steele »

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #21 on: July 28, 2020, 10:50:28 AM »
Arctic going back into the 1960's? Well, this is what happens, when people overanalyze details too much and lose sight of the big picture. And unfortunately that happens a lot in the society. Time to zoom out again.

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #22 on: July 28, 2020, 05:37:10 PM »

 Read back the beings of this thread. Take note the “great salinity anomalies” and the dates of those events. Are there similar Atlantic salinity anomalies over the last few decades that the Beaufort gyre has been spinning up and adding fresh water at it’s center?  Do large freshwater pulses have potential effects on MOC?  Are the 60s and 70s relevant?

I deleted some of this thread , not relevant to discussion... misunderstanding
« Last Edit: July 28, 2020, 11:07:23 PM by Bruce Steele »

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #23 on: July 28, 2020, 05:46:42 PM »
Changes in Arctic currents can be analyzed without making outrageous claims like Arctic ice extent in 2050 is going to look like 1960. Unfortunately this immediately invalidates the premise of what to discuss.

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #24 on: July 28, 2020, 06:00:05 PM »
Where is any discussion on this thread making that claim over the many years people have posted here.
 Deleted as above

 


« Last Edit: July 28, 2020, 11:13:54 PM by Bruce Steele »

Juan C. García

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #25 on: July 28, 2020, 06:39:11 PM »
I remember reading a scientific article that said that a Beaufort gyre reversal will push the multi year Arctic sea ice to the Fram Strait, making the possibility of a BOE. I don't have time to look for the article, but I believe it is possible.

Completely the opposite impact to what this topic title is suggesting.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Bruce Steele

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #26 on: July 28, 2020, 07:51:45 PM »
Juan, I think the discussion of what happens when a reversal happens is what this thread is about. The loss of a large amount of Beaufort gyre surface fresh water is bound to make some salinity changes in other parts of the arctic and the North Atlantic. That reversals caused effects in the sixties and seventies may have relevance to future reversals or series of reversals.
 I am still interested in whether the shoaling of the halocline exposes shelves and canyons to warm and saline waters currently circulating in the gyre. The top of the halocline is closer to the surface this year.
We only have two buoys ITP bouys with working temp/ salinity contours. They are both close to the center of the gyre but the changes I am interested in are on the shelves and areas subject to upwelling.
 I still don’t understand why any premise invalidates discussion.
 I took offense at “ this is what happens when people overanalyze details too much and lose sight of the big picture “. The statement makes no distinction between the premise of the original paper and the discussions taking place on this thread. And because I am directly upthread of Jens post it implies I am who Jens is disparaging .

 

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #27 on: July 28, 2020, 08:45:43 PM »
And because I am directly upthread of Jens post it implies I am who Jens is disparaging .

Not really, it was just a reaction to the title and OP.

If the premise was that "there isn't a scientific consensus on the exact upcoming impact", we would be better off to start out with a more open mind.

The thing reminds me of some people saying that if Gulf Stream cools/slows down, then we would get a new ice age in Europe. Well, not really. At most it would slow down or perhaps temporarily halt warming process in Europe, but the overall global warming is still enough to overcome these regional processes.

So I view Arctic similarly. The currents may move in one way or another, but overall warming will easily overcome whatever mostly temporary regional effects these shifts would have. We are still moving towards ice-free Arctic. Just the exact scenarios and exact timelines in which things would happen are still up in the air.

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #28 on: July 29, 2020, 12:40:31 AM »
I remember reading a scientific article that said that a Beaufort gyre reversal will push the multi year Arctic sea ice to the Fram Strait, making the possibility of a BOE. I don't have time to look for the article, but I believe it is possible.

Completely the opposite impact to what this topic title is suggesting.

Juan, I think the discussion of what happens when a reversal happens is what this thread is about. The loss of a large amount of Beaufort gyre surface fresh water is bound to make some salinity changes in other parts of the arctic and the North Atlantic. ...
 
 I still don’t understand why any premise invalidates discussion.
 I took offense at “ this is what happens when people overanalyze details too much and lose sight of the big picture “. ...

Hi Bruce Steele.

I was not trying to offend and I am not trying to avoid block or derail any useful discussion. I am not an oceanographer and I know my limitations understanding this subject.

On 2016 the Arctic had a strong Beaufort gyre and I tried to learn about it, so I found a study about a reversal on the Beaufort gyre. I was surprised that they were talking that it could make an ice-free Arctic. At that time, I found it hard to believe, but now, after seeing that the “strong multi year ice” close to Canada and Greenland start to crumble, well, I think that a reverse Beaufort gyre could be a beginning of a BOE. It is just an amateur point of view, but I really read a scientific study about it.

Other than that, I respect the discussion that you can have here and I know that there are several people that have more knowledge than me on this subject.

Have a great day, Bruce and everyone!
« Last Edit: July 29, 2020, 01:58:16 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Bruce Steele

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #29 on: July 29, 2020, 03:26:44 AM »
Juan, I suppose I have discouraged discussion and that was not my intent. We have all been watching ice while a  predominately anticyclonic systems have dominated the Beaufort gyre system. This has gone on so long now that we don’t know how the arctic would respond to a long series of cyclonic systems.
The gyre has broken down in the past but how it would respond with such a diminished ice volume as we now have no one knows. Where the surface water would go and what effects it might cause or potentially where the much warmer and saltier halocline might go is more detail than we confidently define. I make no claims. I watch some buoys and try to think about what they are telling us.
 Today one buoy somewhat close to the McClure sound entrance had temperature increases that insolation wouldn’t explain because it is very cloudy there today. The ice moving around causes the heat built up below the ice to mix to the surface but there might be flows out of the sound affecting bouys nearby also. There are ten working temperature sensors in the Beaufort right now and almost all of them are showing water temperatures about -1.2. The two buoys that record deeper in the water column show the same -1.2 all the way down to the halocline at about 35 meters. I think there is a lot of heat in a big area of the surface water this year, every buoy working shows warm temperatures. We still have more insolation possible in the Beaufort when the clouds clear and as more and more area melts out the open waters will heat well above zero.
 Juan, I watch your updates every night as they arrive about bedtime. Last thing I see before lights go out. Thanks for the work and consistency.
 

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #30 on: July 30, 2020, 02:41:27 PM »
It is ok, Bruce. No hard feelings.
I tried to find the study that I mentioned before, without success. I didn't keep it in my files and I don't find it on internet.
So please continue with your analysis. I don't have knowledge about this topic.
Quote
Juan, I watch your updates every night as they arrive about bedtime. Last thing I see before lights go out. Thanks for the work and consistency.
You are welcome.  :)
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Général de GuerreLasse

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #31 on: July 31, 2020, 05:14:44 PM »
Hello Juan C Garcia, this is my first intervention on ASIF. I have decided to give up the crown of ASIF's oldest lurker ;). AbruptSLR had published this paper last year. It doesn't talk about BOE but it is nevertheless worrying. I hope it can help you. And if Bruce watches your updates every night before going to bed, I watch them every morning when I wake up.
ASIF is a wonderful place.  :)

quote:
"In a 2018 study, scientists have found that the amount of heat in the trapped warm layer in the Beaufort Gyre, a major Arctic Ocean circulation system north of Alaska, has doubled over the past 30 years. And, if the temperatures continue to spike, it could eventually spell trouble for the ice above."

https://www.whoi.edu/oceanus/feature/a-ticking-time-bomb-in-the-arctic/?fbclid=IwAR317B222eqL65aMwNhWkRlsYK00mAKtBDI0V2mirQWuGBMpsVD36nA_yVU
« Last Edit: July 31, 2020, 05:28:30 PM by Général de GuerreLasse »
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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #32 on: July 31, 2020, 10:08:39 PM »
Welcome Général.

PS:ALSR posted it last year which is not quite the same as published.
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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #33 on: July 31, 2020, 11:03:24 PM »
Quite right kassy, it is necessary to be rigorous and to respect the semantics and syntax. Otherwise the thought gets lost and you end up not knowing what you are talking about.
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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #34 on: August 01, 2020, 01:44:14 AM »
The linked reference discusses the stability of the Arctic halocline and the use of available potential energy (APE) as a measure of the vulnerability of Arctic sea ice to the upward heat fluxes from the interior of the Arctic Ocean.  In this regard, the first image (Figure 5 of the reference) shows how APE has allowed freshwater to accumulate in the Beaufort Gyre (as compared to earlier periods) and the reference indicates that if the APE changes in the future to allow much of the surplus freshwater in the Beaufort Gyre (see the second image) that this could abruptly disrupt the Arctic Ocean halocline, which could result in the abrupt reduction of Arctic Sea Ice Extent via the upward migration of ocean heat energy previously trapped beneath the halocline.  Furthermore, if the Arctic Sea Ice Extent were to be abruptly reduced then the depth of the wind mixed thermocline would increase thus potentially exposing the seafloor on various Arctic Ocean continental shelves to higher temperatures.  Furthermore, an abrupt release of freshwater from the Beaufort Gyre into the North Atlantic would cause much of the heat content of the Gulf Steam to penetrate deeper in the Arctic Ocean.

Igor V Polyakov et al (2018), "Stability of the arctic halocline: a new indicator of arctic climate change", Environ. Res. Lett., 13, 125008,

https://iopscience.iop.org/article/10.1088/1748-9326/aaec1e
https://iopscience.iop.org/article/10.1088/1748-9326/aaec1e/pdf

Abstract: "In this study, we propose a new Arctic climate change indicator based on the strength of the Arctic halocline, a porous barrier between the cold and fresh upper ocean and ice and the warm intermediate Atlantic Water of the Arctic Ocean. This indicator provides a measure of the vulnerability of sea ice to upward heat fluxes from the ocean interior, as well as the efficiency of mixing affecting carbon and nutrient exchanges. It utilizes the well-accepted calculation of available potential energy (APE), which integrates anomalies of potential density from the surface downwards through the surface mixed layer to the base of the halocline. Regional APE contrasts are striking and show a strengthening of stratification in the Amerasian Basin (AB) and an overall weakening in the Eurasian Basin (EB). In contrast, Arctic-wide time series of APE is not reflective of these inter-basin contrasts. The use of two time series of APE—AB and EB—as an indicator of Arctic Ocean climate change provides a powerful tool for detecting and monitoring transition of the Arctic Ocean towards a seasonally ice-free Arctic Ocean. This new, straightforward climate indicator can be used to inform both the scientific community and the broader public about changes occurring in the Arctic Ocean interior and their potential impacts on the state of the ice cover, the productivity of marine ecosystems and mid-latitude weather."

Caption for first image: "Figure 5. Strength of Arctic halocline illustrated by the APE as an indicator of Arctic Ocean climate change. (a) Map showing APE difference between two selected periods of time. (b), (c) Time series showing APE averaged over (b) the entire Arctic Ocean and (c) Amerasian (red) and Eurasian (blue) basins. (d) Conceptual model of change of Arctic halocline strength showing: (i) decrease in time of sea ice, (ii) enhanced impact of Arctic High on ocean circulation, (iii) increase of thickness of SML and halocline in the AB and decrease in the EB, (iv) increase of influx of Pacific Water (PI), (v) reduction of EB halocline.

Extract: "The potential significance of the proposed Arctic climate change indicator is far reaching. In addition to providing fundamental knowledge regarding the dynamics of the Arctic halocline (figure 5), this indicator will provide impetus for improved representation of Arctic sea-ice responses to halocline changes in climate models. It may serve as a measure that delivers lead warning of impending changes in Arctic Ocean water mass structure and potential impacts on ice cover, upper ocean biology related to light and nutrient availability, and impacts on human activities (fisheries, shipping) and mid-latitudes. Further, the proposed indicator provides a foundation for the development of further hypotheses about Arctic climate system functionality. Thus, the proposed indicator will be an important contributor to the existing sets of Arctic climate change indicators."

Next, to reiterate about the risks associated with a potential abrupt release of relatively fresh and relatively warm water from the Beaufort Gyre, the third image shows the current weather pattern trend that has allowed a surplus of fresh/warm water to be accumulated in the Beaufort Gyre, and the fourth image shows the weather pattern trend that would allow for the release of this surplus of fresh/warm water first into the Arctic Ocean and then into the North Atlantic where calculations indicate that the current volume of surplus fresh/warm water is sufficient to abruptly slow the MOC once released into the North Atlantic.
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Juan C. García

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Re: Beaufort Gyre Reversal and a Return to 1960's Level SIE
« Reply #35 on: August 02, 2020, 12:14:18 AM »
Hello Juan C Garcia, this is my first intervention on ASIF. I have decided to give up the crown of ASIF's oldest lurker ;).

Welcome to the ASIF, Général de GuerreLasse.  :)

It has been a while since the topic of a gyre reversal has been discussed. Although the Beaufort Gyre used to reverse direction and spin counterclockwise every 5 to 7 years it has now been 21 years since a reversal has occurred. The fresh water in the Gyre has continued to increase as has the Pacific Warm Water in the Beaufort. I was looking for new studies but I didn't find any. The WHOI Beaufort Gyre webpage has a reference to " Arctic Sea Ice Forum "  and ASLR has as good a summary as I can find. 

https://www.whoi.edu/website/beaufortgyre/home

So there is a long range , one week , projection of a strong low pressure setting up over the Gyre. I would think one of these years a reversal will happen . If there was a concurrent Garlic press set-up ...
Anyhow it would be something different than the Arctic we are used to watch melt and freeze.

For those who want a fast and easy way to learn about this topic, I recommend the following video, that comes from the link that Bruce Steele have on the quote.

Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.