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Messages - uniquorn

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1
All hail HTML, CSS, Javascript and the W3.CSS template creators.

I managed to combine a beautiful slider with an image slideshow. Now I have the tools to easily compare years against each other. The images are updated in the same place to a new year for easy comparison instead of putting all images into a huge grid like on my old website.

These news are posted here due to the first content using this are the Snow Covered Days maps.

https://cryospherecomputing.tk/Snow-Cover

2
Similar to my last post, the linked reference finds that the Pacific Decadal Oscillation, PDO, is heavily influenced by ocean circulation patterns (which will be increasingly influenced by ice-climate feedback mechanisms in coming decades).  As the PDO plays a major role in the ENSO and El Nino frequency, it will be interesting to see how continued global warming influences the PDO-ENSO dynamic:

Robert C. J. Wills et al. (15 January 2019), "Ocean Circulation Signatures of North Pacific Decadal Variability", Geophysical Research Letters, https://doi.org/10.1029/2018GL080716

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018GL080716

Abstract
The Pacific Decadal Oscillation (PDO) is the dominant pattern of observed sea surface temperature variability in the North Pacific. Its characteristic pattern of eastern intensified warming and cooling within the Kuroshio‐Oyashio Extension is pervasive across timescales. We investigate the mechanisms for its decadal persistence in coupled climate models, focusing on the role of ocean circulation changes. We use low‐frequency component analysis to isolate the mechanisms relevant at decadal and longer timescales from those acting at shorter timescales. The PDO warm phase is associated with strengthening and expansion of the North Pacific subpolar gyre in response to a deepening of the Aleutian Low. The subpolar gyre takes several years to respond to wind stress forcing through baroclinic ocean Rossby wave adjustment, such that white noise atmospheric forcing is integrated into red noise, increasing variability at long timescales. Sea level anomalies within the Kuroshio‐Oyashio Extension provide an observable ocean circulation signature of North Pacific decadal variability.

Plain Language Summary
North Pacific sea surface temperatures vary from decade to decade with a characteristic pattern, where temperature anomalies near North America are opposite to those off the coast of Japan. These ocean changes influence fish populations as well as climate over the surrounding land regions. Here we investigate the physical mechanisms for this sea surface temperature variability using global climate models that include interactions between the atmosphere and ocean. We find that ocean currents change together with the changes in sea surface temperature and that the time it takes for these ocean currents to adjust to changes in the prevailing wind patterns gives this variability its persistence from decade to decade.

3
Policy and solutions / Re: Renewable Energy
« on: February 14, 2019, 05:37:46 PM »
Lurk, Hang in there, I enjoy your posts. If I ever get to the complete system of renewable energy, renewable food production , transportation and home heating I would welcome a critical analysis of my efforts.
 I have focused on food first as I believe it is of critical import and largely neglected. Anyone attempting renewables to power their food production requirements will quickly realize they need to change their expectations . We are so dependent upon the food transportation network and enormous numbers of food miles currently built into our diets. Bananas, citrus, tropical fruit on menus thousands of miles separate from their points of production. Even greens and salads available in the Northern parts of the US where we recently saw -35 F.  Renewable and local will require a change in these expectations. Diets should be built around local availability IMO but you don't need to worry about this problem if you don't actually try producing your own renewable energy.
 Renewables are also locally constrained and some currently occupied regions may in fact not support any renewables options that can maintain anything similar to current lifestyle expectations or population densities. Wind works in some areas, solar or hydro in others. Wood as a heat source is in reality not an option in many areas lest we cut down every tree and bush in a vain attempt to heat our ( overly large )homes. 
 Transportation seems to be everyone primary interest because it is critical to maintaining the infrastructure that obviates my first two points. I may be contrary but I believe local should be our primary consideration because any honest assessment of the renewable energy required to maintain the transportation infrastructure will not work in decadal  timeframes . Yes very rich societies that have fossil fuel resources to build out electric trucking and large personal EV vehicles ( Teslas ) may seem at first sustainable but those options will fail as the fossil fuels to create them begin to fail. Self supporting renewable infrastructure requires serious efforts at walking back our expectations of luxury and anyone who try's to put a total support structure together will quickly realize this point. We need to figure out how to live on less energy inputs rather than create an imitation of how we currently live. Yes electric vehicles are part of a renewable future but those vehicles will be small, light and not expected to travel very far.
 Home heating / cooling is also feasible as we move forward but local resources should drive local architecture .
 Lastly we need to figure out how to sink some of the excess carbon we have already emitted which leads me back to food and farming. Farming with renewables and locally sourced energy and biomass needs seems to be a full circle solution but also a very labor intensive one. It requires major changes in current lifestyle expectations. It also can be adapted to further steps down the energy escalator we have become conditioned to expect, the elevators will not always go up. If or when solar, wind, and batteries go through their replacement cycles farming can still go on even if that means we transition back to beasts of burden.
If we put all of our efforts at high expectation transportation networks and fail to maintain our food and farming past/ future the bottleneck will narrow.

4
Arctic sea ice / Re: Latest PIOMAS update (January)
« on: February 05, 2019, 09:32:16 AM »
While waiting for the lastest January data, here is an animation of the full range 1979-2018. Made possible by a recent inclusion of 1979-1999 daily thickness data.

Displayed are thickness data every 5th day to keep the file size relatively limited.

It is coded as an mp4 file, experimental for me, over 13meg in size, see it works for you.


5
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 16, 2019, 06:52:03 PM »
FYI, the ECMWF and GFS models saw the SSW coming although they have been struggling with the details on how the deceleration of the vortex in the high stratosphere would work its way down in the atmosphere. I have been surprised about how well the CFS model has done at getting the big picture right about the SSW beginning to affect surface weather strongly around January 15.

I wrote about the developing SSW on 19Dec18.
https://www.dailykos.com/stories/2018/12/19/1820257/-Thirty-Mile-High-Wave-Encircling-Earth-to-Break-over-North-Pole-on-Christmas-Day

6
Arctic sea ice / AMSR2 Snow & Ice Volume/Thickness
« on: January 03, 2019, 09:01:01 PM »
AMSR2 thickness and volume ties with 2013 and 2014 for the highest values.

Full size images + gif +netcdf at:
https://cryospherecomputing.tk/SIT

7
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 26, 2018, 10:31:29 PM »
AMSR2 image for 3rd December contrasted with present extent line (in orange).

The front has extended slowly south in the vicinity of Svalbard but it's tough going against the west Spitsbergen current.

Meanwhile the retreat in the Kara is around 200km long !

8
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 13, 2018, 12:03:04 AM »
Per CIS, the Parry Channel is mobile again.

Also, there's this one ARGO float sitting in the warm current NE of Svaalbard (~82N 39E).
It's taking profiles every day, and it's quite Atlantified there.

9
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 04, 2018, 11:45:53 PM »
When will I get credit for harping on this continuously... probably never but that's OK  8)
You would get much more credit for focusing on important snow issues if you didn't insist on confounding this with impending glaciation.

bbr2314 post #5 (out of 1515). The only change is the expected timespan. Down from a few centuries to... next week?

Question:

The Hansen maps show declines in temperatures surrounding areas affected by the NATL cold pool, with anomalies increasing (in a negative direction) as the Greenland melt accelerates.

Could the lingering Hudson Bay ice and the very cold Quebec this summer also be a result of this, and if the positive feedback continues accelerating, perhaps it's possible that higher elevations of both Scotland and Quebec see re-glaciation over the next few centuries, while Greenland gradually melts out?

On topic: Snow cover being more than 1 standard deviation off compared to historical data - is that such a big deal? For a normal  distribution only 68% of the samples are expected to be within +/- 1 SD. If the trend over the years is positive even more samples would be expected to be over +1 SD.

10
Arctic sea ice / Re: Latest PIOMAS update (December)
« on: December 04, 2018, 05:25:07 PM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

I agree with Binntho. No gridded cells could explain that difference.

But in fairness, the PIOMAS is a better effort than the AMSR volume chart posted earlier by Tealight.

Look at the two areas circled in black. Parts of Area A in the Laptev were still not fully ice covered in early November and now it is supposed to be nearing 150cm thick ! PIOMAS puts the same area in the 75cm to 1m bin. Which is probably even a little generous.

Meanwhile Area B shows a river of blue going right up the centre of the Arctic Basin. That's less than 50cm thick. Clearly incorrect. 

11
Arctic sea ice / Re: Latest PIOMAS update (November mid-monthly update)
« on: December 03, 2018, 02:12:10 AM »
The November coldness seems have had an impact on the ice. Both thickness and volume increased way above previous years.

Full size images + gif +November netcdf at:
https://sites.google.com/site/cryospherecomputing/amsr2-sea-ice-volume

12
Welcome back ASLR.

With a limited bandwidth ;)

Thanks,
ASLR

13
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 25, 2018, 04:43:53 AM »
Attaching the early online release of Meneghello.

14
The linked reference provides paleo-evidence that prior to the PETM, many of the Earth's carbon cycles became destabilized (i.e. weakened negative feedbacks and greater sensitivity to small shocks).  This is not good news, but this information may be useful in helping to better calibrate state-of-the-art Earth System Models:

Armstrong McKay, D. I. and Lenton, T. M.: Reduced carbon cycle resilience across the Palaeocene–Eocene Thermal Maximum, Clim. Past, 14, 1515-1527, https://doi.org/10.5194/cp-14-1515-2018, 2018.

https://www.clim-past.net/14/1515/2018/

Abstract. Several past episodes of rapid carbon cycle and climate change are hypothesised to be the result of the Earth system reaching a tipping point beyond which an abrupt transition to a new state occurs. At the Palaeocene–Eocene Thermal Maximum (PETM) at  ∼ 56Ma and at subsequent hyperthermal events, hypothesised tipping points involve the abrupt transfer of carbon from surface reservoirs to the atmosphere. Theory suggests that tipping points in complex dynamical systems should be preceded by critical slowing down of their dynamics, including increasing temporal autocorrelation and variability. However, reliably detecting these indicators in palaeorecords is challenging, with issues of data quality, false positives, and parameter selection potentially affecting reliability. Here we show that in a sufficiently long, high-resolution palaeorecord there is consistent evidence of destabilisation of the carbon cycle in the  ∼ 1.5Myr prior to the PETM, elevated carbon cycle and climate instability following both the PETM and Eocene Thermal Maximum 2 (ETM2), and different drivers of carbon cycle dynamics preceding the PETM and ETM2 events. Our results indicate a loss of resilience (weakened stabilising negative feedbacks and greater sensitivity to small shocks) in the carbon cycle before the PETM and in the carbon–climate system following it. This pre-PETM carbon cycle destabilisation may reflect gradual forcing by the contemporaneous North Atlantic Volcanic Province eruptions, with volcanism-driven warming potentially weakening the organic carbon burial feedback. Our results are consistent with but cannot prove the existence of a tipping point for abrupt carbon release, e.g. from methane hydrate or terrestrial organic carbon reservoirs, whereas we find no support for a tipping point in deep ocean temperature.

15
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 10, 2018, 02:58:17 PM »
The big question is of course: are we transitioning to a new climate mode (huge low pressure zones and storms above the Arctic, sucking in warm air from the midlatitudes, keeping the Arctic fairly warm, not letting the ice freeze, which keeps the stormy weather alive/low pressure systems in a feedback loop)?

Are you suggesting that the southern wall of the Arctic Polar Cell is breaking down?

16
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 10, 2018, 10:28:50 AM »
I think there's a threshold that needs forcing through, whilst there's enough ice around the pole to preserve an ice desert the ice will always regenerate and expand. The ice around the pole has to be accelerated to force it south, 0kph at the pole @175kph at the northernmost tip of Greenland, any wind powerful enough to do that also serves to enhance the ice deserts regenerative ability. The warm currents entering the Arctic either fall into the deeps or have too much inertia to move towards the pole, mostly both. We may have to wait until the temperature  of the ocean itself has the energy to cause bottom melt in the CAB.
 Looking at the various animations this year [thanks everyone] it seems pretty clear that the ice is expanding from the center out towards either the exits or to be destroyed by wave action, with the possible exception of ESS where there was thick ice left over from last season in sufficient quantity to almost serve as it's own ice desert. At the moment I can't see how a seperate area of thick ice could be established, so we may see the CAB under siege on all fronts. 

17
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 07, 2018, 09:22:26 PM »

Why would a weaker AMOC lead to more transport up Norway instead of Labrador?
My understanding of that:

1) Overturning happens when the surface water becomes (slightly) denser than the intermediate water beneath it
2) Weaker OC implies a water column that is less dense (particularly in the surface layer)
3) This further implies a higher sea surface height (more like a less pronounced depression in SSH)
4) Gradients in sea surface height influence ocean currents, particularly in areas where the sea bed is at ~500m depth - such as the ridges from Iceland towards the SW (along the Mid Atlantic Ridge), and to the Faroe Islands, and also the entrance to the Barents Sea and the ridge NW of Svaalbard

So all else equal a stronger OC in the Sub-Polar Gyre (S tip of Greenland) pulls more of the ex-gulf stream water in the Iceland/Faroe Islands region towards Iceland and spiraling into the SPG, instead of towards the Faroe Islands and up the Norwegian coast. Stronger OC in the area around Jan Mayen pulls more warm(ish) water into that gyre instead of into the West Spitzbergen Current and the Barents Sea.

Conversely, a weaker AMOC in both gyres allows more ex-gulf stream water into the Arctic and Barents.

Basically that ~500m deep ridge from Scotland to Iceland, and SW along the MAR, is a perfect switch that responds to small changes in water density in the deep water regions surrounding it. In deeper water, currents are perpendicular to SSH gradients like wind following isobars, but in shallow water currents can just go from high SSH to low SSH.

18
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 07, 2018, 03:48:56 PM »
Careful analysis of Mercator ocean cross sections and animations led me to conclude that warm salty water wrapped into the coastal area near the tip of Greenland, then was cooled by intense storms and cold air, last winter and early spring. Oceanic deep convection was intense after the major stratospheric warming drove cold air towards the Labrador sea and the far north Atlantic.

Summer and early fall cool SST anomalies south of Greenland are indicative of a shallow warm fresh layer that has been disturbed by storms. And amplified flow of cool water from the CAA through the Labrador sea into the north Atlantic. Cold SST anomalies in the late winter and early spring are indicative of weak deep convection, not summer temperatures.

Apparently a major reason that warm Atlantic water was moving into the Arctic from 2005 through 2012 was a weak overturning circulation. Instead of heading for the Greenland and Labrador seas, warm salty water headed up the coast of Norway for the Arctic ocean.

There's a recent report that deep convection in the Greenland sea has increased as ice has decreased on the continental shelf edge. Salty water is now able to penetrate the shelf then cool and sink.

There are probably other reasons that the Atlantic side of the Arctic ocean is apparently cooler than it was a few years ago. One may be that it's actually warmer at depth in parts of the Barents sea region. Stormy weather directs more water to the right of the Fram strait towards Murmansk and the Barents sea. Stormy weather prevents warm surface layers from building up, but the subsurface is warmed by mixing.

There's a lot going on. I await reports from professional oceanographers to make sense of it all.

19
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 06, 2018, 11:18:49 PM »
Squeezed in a blog post on this before the PIOMAS numbers get updated: Freezing season has started, or has it?


20
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 02, 2018, 11:20:25 AM »
Can someone explain me how so much heat can intrude towards the N.Pole from the Pacific? How can that happen? Any specific mechanisms?
I'll take a punt, Amundsen is not huge lets say 300 by 100 km and the tides are not huge .2-.6m but it's the only game in town. The tidal forcing twice a day drives a current across the Canadian/Alaskan mainland that detatches the incoming Pacific water from the coast at times and consistently provides resistance to it's ingress. The Pacific water backs up and flows instead into the deep west of Chuckchi Plateau here it meets and mixes with the increasing flow of Atl. water coming past the Lomonosov ridge. Some fraction gets caught up in turbulence caused by the tail end of the Amundsen driven current. Just as Amundsen drives water out twice a day so it draws it in, from the general direction of NSI but likely from just north of Chuckchi plateau. The easiest fraction of water to move is the surface so the Pacific waters are also drawn into the area where the Amundsen bound surface current begins.
   It's well worth looking through the various parameters at the link, i do full tilt/full screen, there's nothing that looks too different to other models.
The link done.

21
Arctic sea ice / Re: Arctic Image of the Day
« on: October 01, 2018, 10:48:06 PM »
Sentinel Colour Infrared Image of Barter Island off the north coast of Alaska on 30th September.

The NWS did mention that "sea ice will likely begin to form near freshwater river deltas and
behind barrier islands along the Beaufort Sea coast during the first week of October."

And indeed it has.

22
Arctic sea ice / Re: The 2018 melting season
« on: September 22, 2018, 12:03:28 AM »
As a result of the huge heat intrusion on the Pacific side, extremely warm September is observed near Cape Dezhnev:

Anadyr:

Pevek:


Red line is the daily maximum. Blue line is the daily minimum. Green line is the daily mean. Red and blue dots are the highest and lowest for this day. Thin lines are the normal minimum, average and maximum.

23
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 05, 2018, 02:07:53 AM »
What's important is the slow but increasing northward push of warm, salty Atlantic water into the subarctic seas and the Eurasian side of the Arctic ocean. Increased release of ocean heat in the dark and dim months through the thin-ice covered Arctic is important. The increase in advection of warm humid air into the Arctic from the Atlantic and Pacific basins is important. The lengthening of fall and the shortening of winter is important. Increasingly vigorous stratospheric warmings are important.

Arguments about how fast a trend is established are academic. They have value in debunking crap like "the Hiatus". However, they are quite irrelevant to the developing ecological and human catastrophes that are being caused by the warming climate and declining sea ice.

24
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: August 30, 2018, 10:51:19 PM »
Note that the warm deep 'archived' water is capped by a cool-fresh layer of water, and the first article indicates that ice mass loss from Greenland has been contributing to feedback mechanisms that has caused the Beaufort Gyre to progressively stockpile more freshwater than all of the great lakes combined (see the first image).  While some consensus scientists will undoubtable emphasize that an eventual release of this freshwater in coming years will result in a temporary cooling of the North Atlantic and Europe, which may decrease GMSTA; I note that such a release of freshwater from the Beaufort Gyre would also slow down the MOC; which in turn would increase climate sensitivity:

Title: "How a Wayward Arctic Current Could Cool the Climate in Europe"

http://e360.yale.edu/features/how-a-wayward-arctic-current-could-cool-the-climate-in-europe

Extract: "The Beaufort Gyre, a key Arctic Ocean current, is acting strangely. Scientists say it may be on the verge of discharging a huge amount of ice and cold freshwater that could kick off a period of lower temperatures in northern Europe.

…something is amiss with this vital plumbing system in the Arctic, a region warming faster than any other on the planet. Thanks in part to rising air temperatures, steadily disappearing sea ice, and the annual melting of 270 billion tons of ice from Greenland’s ice cap, the gyre is no longer functioning as it has predictably done for more than a half century. And now, scientists are anticipating that a sudden change in the Beaufort Gyre could set in motion events that — in a steadily warming world — would actually lead to a temporary but significant cooling of the North Atlantic region.

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….

The gyre’s strange behavior is likely linked, at least in part, to the profound warming of the Arctic, and it demonstrates how disruptions in one rapidly changing region of the world can affect ecosystems hundreds, even thousands, of miles away. In a recent paper, Krishfield, Proshutinsky, and other scientists suggest that frigid freshwater pouring into the north Atlantic Ocean from the rapidly melting Greenland ice sheet is forming a cap on the North Atlantic that results in stratification that prevents storm-triggering heat from the northern end of the Gulf Stream from rising to the surface. The scientists say this may be inhibiting the formation of cyclones that would cause the motion of the gyre to weaken or temporarily reverse.

If that is the case, it may mean the gyre will continue to grow and spin clockwise for years to come."

See also:

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."

&

The third linked Marino & Zahn (2015) reference (and second 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 third image); which per the fourth 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

&

The fifth linked reference about the influence of the recent increased Agulhas leakage on tropical Atlantic warming and the response of the AMOC:

Joke F. Lübbecke, Jonathan V. Durgadoo, and Arne Biastoch (2015), "Contribution of increased Agulhas leakage to tropical Atlantic warming", Journal of Climate, doi: http://dx.doi.org/10.1175/JCLI-D-15-0258.1


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0258.1

&

The sixth linked reference (with a free access pdf) indicates that the leakage of warm saline water from the Agulhas Current into the Atlantic Ocean, caused a positive feedback mechanism contributing to polar amplification during the Eemian; and that this mechanism could become increasingly important with increasing global warming today:

Turney, C. S.M. and Jones, R. T. (2010), Does the Agulhas Current amplify global temperatures during super-interglacials?. J. Quaternary Sci., 25: 839–843. doi: 10.1002/jqs.1423

http://onlinelibrary.wiley.com/doi/10.1002/jqs.1423/full

25
Arctic sea ice / Re: Arctic Image of the Day
« on: August 30, 2018, 12:39:34 AM »
Deconstruct, you sound as if you never made a mistake or an error or a false claim while posting. If so, I envy you, but recommend to remember that normal people do make mistakes.

P.s I note that claiming Treform said "obliterated" is a false claim, perhaps fake news? Or just a plain mistake.
1)
I did acknowledge my error without any hesitation and apologized immediately. And If I make a false claim, I am happy to be corrected, because I want to believe as many true things as possible, and as little false things as possible. And anybody who helps me with that is welcome.

2)
Does it make any difference for the argument, if Treform said "obliterated" instead of "collapsed"? It does not. It is synonymous and interchangeable from the meaning and that is why I mixed up who used what of the two words. It both means that the ice shelf has vanished, gone poof, broke down, dissolved, [put-in-you-favorite-synonym-here]. That was an error of mine, but it doesn't change the meaning and my argument a single iota.

Does it make any difference, if I say that an ice shelf collapsed, when it did nothing of that sort, not even close, or if I dont make such a false claim? Yes it does.

If you can't see the difference in that two things, I can't help you.


If only this had been all you said instead of what you did say.
Based on the reactions of some people here, that rather defend a wrong statement or search for excuses, I am now to the contrary more convinced, that it was necessary to talk more extensively about that topic. Even if you don't like that.

26
Arctic sea ice / Re: What the Buoys are telling
« on: August 29, 2018, 08:56:05 AM »
It still has a location reported for 2018-08-29, so it's not 1).

2) would be an interesting theory if it had been moving consistently in one direction and then just stopped... but it looks like it's last movements have been a bit back and forth in no particular direction, but over a range >> 1.4km.

So 3) seems most plausible to me, but I haven't looked at nearby weather data or anything.

One thing I found interesting, last time I looked the profiler was ~220m deep, in water 200<depth<500. Now it is at 477m in an area close to the 500m isobath. Not just the cable, but probably also the profiler itself is dragging along the sea floor.

27
Arctic sea ice / Re: Arctic Image of the Day
« on: August 29, 2018, 12:32:39 AM »
The hazards of research near the pole.


28
Arctic sea ice / Re: The 2018 melting season
« on: August 13, 2018, 07:43:41 PM »
Although ITP 108 isn't working as a profiler it is still sending out it's location. It looks like it is going to exit the Beaufort Sea via the Amundsen Gulf. Too bad the profiler is broken , it would be interesting to see how much  fresh water is exiting with it. This is a strange track for a profiler buoy.

29
Arctic sea ice / Re: meaningless freezingseason/melting season chatter.
« on: August 10, 2018, 09:52:49 PM »
Looking around Sentinel Playground (atmospheric correction, gain: .4; gamma .8 ), I noticed two floes in the Lincoln Sea, about the same size, close to each other, but with very different appearance.  Both have what I understand are blue melt ponds, same scale (lower right corners), same date (August 9), but different texture: "A" seems to have quite consistent parallel lineatiosn (mostly near horizontal, but near vertical in lower portions of the image) and cracks that appear 'about to go'.  "B" has what appear to be several 'old' floes very well glued together.

I don't know enough to draw 'significant' conclusions.

30
Arctic sea ice / Re: The 2018 melting season
« on: August 06, 2018, 11:06:46 AM »
"Hot spots" both are the result of deep warm water being forced upwards the one to the south-west at the end of a long trough , the other at the end of the bear island trough, i have no opinion about how hot they are, but their actual temp. as published varies seasonally.
 
Looks to me that this season [and next] may be defined by how much fresh Beaufort water is lost through CAA/NWP

31
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 05, 2018, 10:55:39 PM »
Time to break out 2018's Arctic minimum running back chart (named after the way it will wiggle through a crowd of dots in a few weeks' time).

32
Arctic sea ice / Re: The 2018 melting season
« on: August 01, 2018, 03:50:43 AM »
We have had an atmospheric circulation vortex around Greenland for over 3 months that was brought on by the major stratospheric warming in February. That stratospheric warming was caused by the strongest wave driving event, which drove energy upwards from the troposphere to the top of the stratosphere, on record.

High drama in rarefied air

This winter, on February 12, 2018, most of us probably were unaware of the compelling drama unfolding high above the Arctic.  The stratospheric polar vortex, the region of west-to-east winds that circle 6 to 30 miles above the pole, (1) experienced a massive breakdown.  The normally west-to-east winds suddenly slowed and switched direction completely as the stratosphere rapidly warmed more than 50 degrees F in a matter of days (see figure below). .....

Why did this sudden stratospheric warming occur? And more importantly (for blog purposes, at least), why should you care?  Let’s start with the first why. Under the right conditions in winter (2), large atmospheric waves (more than 1000 miles across) travel from the lower atmosphere into the stratosphere. These waves break in the stratosphere, like ocean waves on a beach, transferring a tremendous amount of energy to the atmosphere.

The effect is to slow down the winds of the polar vortex (sometimes splitting it into two smaller vortices).  As the winds slow, air sinks and rapidly warms while the stratospheric air is compressed. This sequence of events is exactly what happened this past February—in fact, we experienced a record-breaking movement of large-scale waves into the stratosphere...




https://www.climate.gov/news-features/blogs/enso/february-and-march-madness-how-winds-miles-above-arctic-may-have-brought

The atmosphere has been destabilized by GHGs. Sudden stratospheric warmings are getting stronger as predicted by climate models. This is affecting summers in the Arctic. The SSW transferred momentum downwards to the tropospheric jet stream, expanding it to record momentum levels in late February and March. After the atmosphere blew its energy in March like a Vegas gambler the jet stream retreated into a vortex around Greenland linked to a track displaced polewards of normal over the Pacific and western north America. Intense high pressure over the subtropical north Atlantic and strong trade winds over the tropics drove heat northwards out of the tropical Atlantic.


33
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 27, 2018, 02:54:13 PM »
OK, I've finished reprocessing all the monthly NSIDC ice concentration data, to see what the effect would be of changing from a 15% threshold for extent to a 30% threshold. 

My guess is it won't change much in the standings. Or not as we expect. DMI used to have a 30% threshold, but they have 15% now too.

Yup, it basically changes ... nothing.  Except it makes the extent numbers artificially lower.  But there's no trend, no difference in the effect in recent years vs earlier years:



Needless to say it's not statistically significant. 

Quote
Remember, the objection against extent is that everything over 15% gets counted as 100%, everything below it is counted as 0% (same with area). If you raise the bar to 30%, there's this segment between 15 and 30% that is now counted as 0% too, whereas area counts it as 15-30%. So, basically you're letting sea ice disappear to artificially lower extent.

The strength of both measures (with their weaknesses) is their combination.

Yes, exactly.  Switching to a 30% threshold would delete 0.72 million km2 of extent on average, so we'd hit the "ice-free Arctic" threshold very slightly earlier.  But it would be an artificial distinction.

34
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 26, 2018, 11:46:13 AM »
Looking at regional AMSR2 extent (the most accurate thanks to its high grid resolution) I have a few thoughts:
* Kara, Hudson and Baffin have about 300k remaining between them. This "easy ice" repository will soon run out.
* The big laggards Beaufort and ESS have joined the ranks at last, but will they keep up?
* The huge question mark for August is the CAB.

Just for the case if you want to create your own graphs:
https://twitter.com/seaice_de/status/1022411701864591360

35
Arctic sea ice / Re: The 2018 melting season
« on: July 05, 2018, 09:20:06 PM »
Ok. http://www.whoi.edu/page.do?pid=160136



That's very cold water sinking off the shelf penetrating deep in to the Atlantic water layer around day 540. That's not warm water mixing up. It will not cause melting. It is a form of convection, but it's intermediate to deep water being formed.

36
Arctic sea ice / Re: How soon could we go ice free?
« on: June 23, 2018, 02:14:49 AM »
Since the ice loss will not be linear, arguing which linear function is best is ridiculous.

Quote
The distinction between linear and nonlinear systems in mathematics defines the boundary between the relatively knowable, and the frustratingly elusive. Both types of systems can describe the dynamics of many different processes, such as planets orbiting each other, fluctuations in animal populations, the behavior of electrical circuits, and so on. The difference between linear and nonlinear lies in the details of the equations that govern how these systems interact. For systems that behave linearly, it is relatively easy to find exact solutions that we can use to predict future behavior within the system. For nonlinear systems, we are lucky to find any such solution. Indeed, in nonlinear dynamics, we often have to redefine what we consider to be a solution.

Here is an excellent introduction to Sensitive Dependence, Iteration, Bifurcation and Feigenbaum's Constants.

http://www.learner.org/courses/mathilluminated/units/13/textbook/04.php

Very nice.  For most systems, there exists a zone of linearity, beyond which a linear function fails.

e.g. Newtonian and Relativist laws of motion.... Newtonian physics are very linear at small fractions of the speed of light.

And how does that even come close to applying to the subject at hand?  Either: 1. You do not understand the math.  or 2. That was an attempt to obfuscate.

The article I linked to was designed to allow even a layman to understand.  Give it a try.

Might I suggest starting back a page, or even from the introduction on the link I gave.  Give special attention to Poincare.

http://www.learner.org/courses/mathilluminated/units/13/textbook/03.php

37
Arctic sea ice / Re: How soon could we go ice free?
« on: June 16, 2018, 02:36:28 AM »
I'm looking at ice dynamics, there are 3 main factors afaics, the main one being the expansion/dispersion of ice with every weather change. That is that as the ice moves creating gaps these are rapidly filled with new ice, the cumulative effect is to push the ice south away from the centre of the ice mass, generally south. As the ice moves south to maintain station it has to accelerate by about 24kph per deg, it doesn't, hence it appears to rotate c/w,  there are pinch points and the ice builds up against the coast, where?   well as far south as Prince Patrick island on the american side, and after the freedom of Beaufort from the NSI through NZ-FJ to Svalbard on the Russian side.
The next factor is the entry of Atlantic water, previously the ice in Barents suppressed the tides, I think ocean currents are residuals of tidal movements, the tides are no longer suppressed and new currents are forming, these currents help to keep Barents free of ice, being free of ice gives the wind free reign, so over the continental shelf the waves thrash the ice, it melts and no longer rotates to accumulate on the american side.     
The third factor is an ice free Amundsen gulf, every tide there can shift a significant fraction of 20,0002km of seawater/ice westward across southern Beaufort, and conversely suck in a similar amount from further north in Beaufort.
Nothing to do with ice but one has to bear in mind that Atlantic/Pacific waters entering the arctic tend to rotate ccw.
If the growing currents coming in from the Atlantic can weaken the ice over the ESAS in concert with weather systems bringing heat from the south, and persistent winds from E/W then the Siberian shelf will also become a killing field for ice. Which gives the possibility of no ice to rotate into the islands, no ice to rotate back towards Amundsen, whats next?
 Well given that systems tend to hold on beyond any reasonable expectation and then suddenly collapse, it's remotely possible that it happens this year, but I don't think we've passed beyond reasonable expectation yet we're close.

38
Arctic sea ice / Re: The 2018 melting season
« on: June 12, 2018, 05:54:02 PM »
Remember, SIA (sea ice area) does not count melt ponds as being 'ice covered sea'.  But as melt ponds are not ice free, SIA gives a false sense of ice loss during the melting season. 
How much area does one pixel cover ?
The bigger the area, the bigger the melt pond required to be excluded from the area total?
Or does the algorithm work in a different way ?
(Warning - Wipneus is 1000 times more qualified to explain this, but let me try)
Each NSIDC grid cell is a huge 25x25 km. You can see the grid "pixels" by enabling sea ice concentration in Worldview. Scrolling this through consecutive days and toggling the ice concentration overlay can teach a lot about the meaning of the data vs. the white/blue/tendril ice you can actually see.
Worldview with sea ice concentration enabled

The size of each specific melt pond doesn't matter. What matters is the total concentration of ice vs. water as sensed by the satellite. When ice concentration drops below 15%, area and extent for that pixel are no longer counted. When ice concentration is above 15%, extent is counted as 100% of that pixel area, while area is counted as the concentration% of that pixel area. Hope this helps.

39
Arctic sea ice / Re: The 2018 melting season
« on: June 05, 2018, 07:46:22 PM »
While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.

The silt is also accumulating heat rapidly. Above freezing values are shaded in 0.6C increments starting at -0.3C - 0.3C bucket. The hottest regions are currently around 4C. Models are showing ice getting transported into this region in the D4-D8 range due to actions of the upcoming Arctic cyclone.


(June 4th worldview).


40
Arctic sea ice / Re: The 2018 melting season
« on: May 30, 2018, 06:25:30 PM »
We shouldn't forget the vorticity of water masses. Because of the spin of the earth, the Coriolis effect tends to turn water masses to the right as they move north or south. Thus, Siberian shelf water tends to hug the coast of Siberia as it moves towards the Bering Strait and Pacific water tends to hug the Alaskan coast as it moves north from the Bering strait. The Beaufort gyre, however is an area of high sea surface heights under an atmospheric high pressure area and they both rotate clockwise.

The inevitable interaction of these different water masses leads to swirling eddies on the margins of the water masses. The position of the center of the Beaufort high has moved polewards this year compared to last year in response to months of anomalous southerly winds.


At the same time the southerly winds and strong sea surface height gradient intensified the Alaska coastal current driving anomalously salty water deeper into the Arctic than last year.



Also note that the Laptev polynya forms at the edge of the shallow Siberian shelf. Offshore winds push ice towards the pole and saltier water wells up from below during southerly wind events. At this time of year, those winds are warm and lead to open water. In winter those winds are cold and cause rapid refreezing.

Cause and effect thinking isn't very useful in a complex, coupled system. To the person who wrote that this melt season isn't very impressive - we will see. This year's extent is the second lowest on record for this date and ice thickness is more evenly distributed across the Arctic this year than in other years. There's more ice to melt out on the Siberian side, but much of it will melt out. The weather models are all inconsistent beyond 5 days so it's anyone's guess what the weather will do and how much ice volume will melt out. This year's more even distribution of volume could lead to an extent cliff in mid to late summer. Again, we'll see.

41
Arctic sea ice / Re: The 2018 melting season
« on: May 28, 2018, 12:38:10 AM »
The AMOC is not simple and the reports on it can be quite confusing because there are different measures of AMOC activity. Moreover, one part of the AMOC can be more active than another part.

There are peer reviewed reports of a general long-term slow down of the AMOC. I take no issue with those reports. The AMOC was relatively quite active between 1988 and 1995 when the Arctic oscillation was strongly positive. The far north Atlantic and the Arctic was very stormy in that period and cold fresh water in the Beaufort gyre was flushed and replaced with warm Atlantic water. After 1995 there was a general slow down in the AMOC as high pressure tended to dominate over the Arctic ocean. There was a severe slow down in the AMOC in 2010. It lead to a build up of tropical Atlantic heat, a bad hurricane season and a slowing of the Gulf Stream that caused flooding at Norfolk Va and other sea level sensitive areas on the U.S. east coast. After that, by some measures, the AMOC picked up.

My statements about the AMOC this late winter and spring are based on Mercator ocean profiles, the persistent Greenland vortex at 500mb and the persistent storms that the vortex has been producing. What many readers don't seem to appreciate is that the warm SST pattern, off of the southeastern and mid-Atlantic states of the U.S. , is a feature that is quite deep. It's not just warm surface waters. The north wall of the Gulf stream goes down over 1000m.




Likewise, the cold anomaly in the subpolar gyre reflects the effects of continued storms that have maintained deep water formation in the Labrador sea into late spring.





The cooling of the tropical Atlantic over the past month is the result of stronger than normal trade winds that moved tropical heat into the subtropics and temperate regions.



To put it simply, the weather patterns this spring are normal patterns that have been intensified by an excess of heat in the northern hemisphere's oceans. The intensification of northward heat transport by the atmosphere is reflected downwards into the ocean. The end result is that the European - Atlantic side of the Arctic is heating up very rapidly this spring. I won't repeat showing the Levitus et all heat content map here, but it shows anomalous heat entering the Arctic from the Atlantic - not good for sea ice.


42
Arctic sea ice / Re: The 2018 melting season
« on: May 20, 2018, 06:04:01 PM »
Multiple things are going on in the depths of the ocean that explain the 2000m heat content increase. The subtropical gyres have expanded polewards in both hemispheres. Even a small northwards displacement of the north wall of the Gulf Stream involves massive amounts of heat. There's a still a thermal gradient below 700m depth.

The coldest water in the oceans, Antarctic bottom water is not forming like it used to. The Weddell sea polynya hasn't been active for decades. As less bottom water forms in both hemispheres the oceans warm in the deepest levels as the volume of the ocean's coldest water decreases with time.

In addition, new bottom water is warmer than old AABW.

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