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Messages - binntho

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1
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 02, 2020, 10:45:55 PM »
But ignorant arrogance tends to stroke it the wrong way.


While I know exactly what you mean and would tend to the same views, it's worth to consider that:


1) We are all ignorant, just not all in the same fields.


2) People with a vast range of knowledge often tend to impatience, anger and sometimes
.   arrogance while the first two can easily make them look arrogant while perhaps they are not.


3) Who denies point 1) above is ignorant and arrogant himself by definition.


This means all is well but it has to be put into account that in relation to all the knowledge that
exists we are all extremely ignorant, not to say stupid. The only difference is that some are a bit more and others a bit less stupid.


BTW anger is NEVER a good approach which does not mean I'm never angry myself but
claiming a RIGHT to be angry is a form of arrogance IM not so H opinion.

2
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: May 23, 2020, 06:38:03 PM »

... as for the "slow down", well that has been repeatedly discussed and I for one have not seen any convincing evidence of there being anything other than an ongoing linear reduction in sea ice with random annual fluctuations. Choosing the record year as the starting point of a hypothetical slow down tastes surprisingly like cherry picking.
Discussed ad nauseam

3
Arctic sea ice / Re: The 2020 melting season
« on: May 23, 2020, 03:03:18 PM »

We don't know what is going to happen in June but so far we are likely going into June in best modern set up to ravage the inner Arctic basin.

I guess that's a matter of opinion. 2012 and 2016 had very weak freezing seasons which preceded them and set the stage with thinner ice. By comparison, 2020 was a much better freezing season. Hoping for a mid-May PIOMAS volume update which gives us a better idea of thickness.

That isn't what we use to define a melting season.

Everyone agrees that 2007 was the melt season on record.

Because the conditions for melt June-Aug were amazing.

If we had an exact repeat of 2007 weather wise we would crush 2012 lows.

The preconditioning that has taken place and is still to come taking place is putting 2020 in one of the best spots  going into June in modern times.

2020 having slightly more ice thickness means nothing if we have melt weather going into June.

Yep, 2011-2012 had a strong winter +AO (Arctic Oscillation) and high area/extent with more volume coming into that spring, yet it was quickly destroyed by preconditioning and the early June dipole. Winter/spring thickness does have an impact, but it explains somewhere around 30-40% of final volume. The rest is up to progressively earlier melt and albedo destruction as the Arctic warms up progressively earlier in the spring. (One small caveat to comparing directly to that season is that the 2011 melt season was a sneaky CAB ice destroyer that didn't show up particularly well on area/extent metrics.)

Speaking of preconditioning, MODIS is indicating some sneaky patchy surface melt and diurnal wetting of the surface in the CAB as we speak. There's a good chance we start seeing more substantial melt by the 28th as that new ridge attempts to set up. Surface temps have been running a little higher than would be expected given the 850/925mb temps we're seeing, but that's probably down to the fact that the big ridge we saw last week has effectively destroyed the low-level cold pool that's typically still present at this time. Since it cannot be regenerated radiatively given the (now) late May sun angle, this might prove crucial. Generally, in the warm season, it takes diabatic processes (cooling through precip and lift), cloud cover, fresh snow and recirculation within a low or TPV to generate a new cold pool and protect the ice. That can still happen, but we're running short on time before the onset of more severe preconditioning. The EC and GFS are in agreement that we should start to see near basin-wide melt starting on the 28th or so.

A couple of important surface stations to watch over the next week (in addition to MODIS pictures) will be Eureka (CWEU) and Alert (CYLT). If those stations are near or above freezing by then and we're seeing significant reddening on the 3-6-7 bands on MODIS, the game is on.


With the Hudson Bay region staying below normal temperature wise, this year is potentially setting up for a big June cliff (Bay melt will probably be delayed to coincide with Basin melt).

4
Arctic sea ice / Re: The 2020 melting season
« on: May 23, 2020, 11:47:29 AM »
Very interesting discussions going on here, and very relevant to the upcoming season.
Just please do not slip into a flame war, no one is cherry picking or bullying. There is also no need to be defensive of one's theories and expectations, as I said already the Arctic can fend for itself.
I remind that more detailed discussions can be had in other threads. Do we have a La Nina or El Nino? There's an 2020 ENSO thread. Status of Arctic rivers can be discussed in detail in the "River ice and discharge" thread.
Effects on the melting season are of course welcome here. I recall 2016's "melting success" was explained in part by the monster El Nino that year, but as far as I can tell neither La Nina nor El Nino have a direct predictable effect on sea ice.
Regarding rivers, I wonder if there is near-delta water temp data (and anomaly) for the various Arctic rivers, besides discharge data.
As for thickness/volume/winter temps, this is an unresolved question. I once tried to correlate regional PIOMAS thickness/volume at certain times with resulting sea ice area at later times of the season for the same regions, and surprising could not find much predictability there. It doesn't mean there isn't a correlation, just that I could not find it with my limited analysis.
I remind that the DMI N of 80 is a misleading chart, due to its peculiar weighting method. Each latitude slice gets the same weight, despite 80-81 being 60 times larger than 89-90. This means the DMI measure is heavily skewed towards the North Pole, and does not tell the whole story regarding the High Arctic in general, some of which is down even to 70deg in the Beaufort-Chukchi-ESS region.  FDDs are another interesting approximation but with its own limitations. PIOMAS does a much more detailed job of calculating energy transfers and ice movements, but it's not the holy grail, it has limited resolution and suffers from inherent data limitations. Cryosat and SMOS measure the ice directly, but with their own known limitations. Snow thickness is the biggest unknown for all of these methods.
This year was colder near the Pole as shown by DMI, but also had a lot of ice movement from that location both to the FJL-Svalbard region and into the Fram. So this may have reduced or negated the advantage of low winter temps.
I think it is quite safe to say that Beaufort ice is indeed thicker this year, and is also starting its movement and breakup (with the resulting area loss) rather late compared to the leading years. This could indeed have a strong effect later on. The other volume anomaly near Svalbard seems doomed, at least as of a month ago and given what we know has happened since then. Of course, there is no telling what will happen from here on.
I think it is also safe to say that summer variability in the Arctic - albedo preconditioning, temperatures, cloudiness, export - is much higher than winter variability, partly because of the diminishing returns of cold temps on further ice thickening. Thus a strong melting weather like 2007 and 2012, or a weak season like 2013 and 2014, makes much more of a difference than the wintertime effects. To wit, both 2013 and 2017 started the year with unprecedented low volume, but ended up with much higher ice than expected.
So it is obvious the season is still side open, with the ice enjoying some strengths and some weaknesses. Of these, the early preconditioning and the Beaufort "fortress" seem to be very important factors, but which of them will prevail depends on June and July.

Note: the source of "my" thickness maps is the PIOMAS April update.

5
Arctic sea ice / Re: The 2020 melting season
« on: April 15, 2020, 06:20:27 AM »
I don't get it. How can this scale be in cm? Shouldn't that be decimeter? 72 cm is less than a meter. 70 dm is 7m.
Not much snow in Siberia, is there? But I'm pretty sure that's more than 2 cm...

Dr. Sean Birkel (who singlehandedly conceived, built, and runs Climate Reanalyzer) sent me this reply about the legend on the snow depth map:
"The plotted units were inches, while the title showed cm.  Found bug...now the plotted values are in cm set to a cm specific color scale."

   Thus, before the correction the snow depth indicated was only 40% of the actual.  Now corrected.

6
Arctic sea ice / Re: Global sea ice area and extent data
« on: April 06, 2020, 06:47:24 AM »
We need a Penguin constellation  over the southern sky!

7
Arctic sea ice / Re: The 2020 melting season
« on: April 02, 2020, 08:56:02 AM »
Thank you binntho.

8
Arctic sea ice / Re: The 2020 melting season
« on: March 24, 2020, 01:01:25 PM »
* It's a lie: Baffin, Barents, Bering and (B)Okhotsk.

Why not just call it very bad BBBO?
Sea 3BO?

9
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: March 06, 2020, 11:40:18 AM »
It has taken a lot of time and energy, successes and failures to build a library of spreadsheets and data sources. So it is a bit annoying to think people have to wade through a load of clutter to reach the data.

This is a data thread. So, please please please bring data or a new way of looking at the data (when discussion is great).

If not, bugger off.



10
Arctic sea ice / Re: "Stupid" Questions :o
« on: February 10, 2020, 09:39:20 PM »
reading the last dozen posts here have left me vulnerable to being contaminated by the stupid virus lol

11
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 07, 2020, 06:47:56 AM »
It has taken a lot of time and energy, successes and failures to build a library of spreadsheets and data sources. So it is a bit annoying to think people have to wade through a load of clutter to reach the data.

This is a data thread. So, please please please bring data or a new way of looking at the data (when discussion is great).
If not, bugger off.

12
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 01, 2020, 09:15:14 AM »
Overnight I realized that my graphs has a big flaw, the fact that the years are normalized with themselves can induce a lot of autocorrelation. For example, if it is the case that a low september minimum is completely random, that would still increase the ratio of normalized winter extent vs normalized september extent, because the low september extent would drag the average for the whole year down, thus increasing the normalized winter extent. Furthermore, since calculating the normalized extent requires knowledge of the average for the whole year, it is not possible to predict anything with it beforehand.

Therefore, I experimented with instead normalizing the years to their predicted average extent from a linear regression of all the years. Now, it should be truly neutral, and also you can make predictions. Unfortunately, doing this does reduce the correlation a lot, but it is still there.

Now, we can make  a prediction for 2020 based on the january value. The high extent compared to the ever-decreasing trend makes this year stand out a lot, the normalized january extent is an all-time high: 1.322. See the red area on the january graph. Will this mean the september extent  will be very low like the graph suggests? Or does it mean the correlation will break down? If we trust the graph naively, the expected normalized september minimum average for this year is 0.42, which is 4.30 Mkm^2 (which is third lowest of all time, behind 2012 and barely 2007), with a lower uncertainty bound of ~2.97 Mkm^2 and a high bound of ~5.33 Mkm^2.




13
Arctic sea ice / Re: Does El Niño affect Arctic sea ice?
« on: January 28, 2020, 06:01:43 PM »
Research Links Sea Ice Retreat With Tropical Phenomena, Including a New Kind of El Nino
https://phys.org/news/2020-01-links-sea-ice-retreat-tropical.html

Two researchers present evidence today in the journal Proceedings of the National Academy of Sciences that the accelerating melt of Arctic sea ice is linked to weather patterns near the equator in the Pacific Ocean.

the researchers said there is strong evidence that the ice melt sets a chain of events in motion that sends cold air equatorward in the upper atmosphere. The two used computer analysis of historical data to identify which atmospheric phenomena also change as Arctic ice diminishes, as it has steadily since 1999. Among the variables that seemed to move in lockstep with ice melt were intensifying trade winds at the equator in the Central Pacific Ocean. The study marks the first time that researchers have looked at both world regions together in this context.

... Though many researchers had thought that air originating in the Arctic couldn't make it to the equator, Kennel and Yulaeva said their work suggests it does.

One consequence is that the nature of El Niño storms changes. Classical El Niños feature build-ups of warm water at the eastern end of the Pacific Ocean off South America. Kennel and Yulaeva's analyses indicate that El Niños starting in the Central Pacific Ocean are the ones that respond to the arrival of Arctic air near the equator. Kennel suggested that since so much of California's rain comes from atmospheric river storms that develop in the Central Pacific, the Arctic-Tropics connection merits further study.

Open Access: Charles F. Kennel et al. Influence of Arctic sea-ice variability on Pacific trade winds, Proceedings of the National Academy of Sciences (2020).

14
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 15, 2020, 10:22:21 PM »

Very interesting. Cloud cover is not everything of course, and in the Arctic, low-lying fog is quite common and probably not counted as cloud. I wonder if anybody is qualified to claim anything about changes in fog prevalence in the Arctic?

Also it'd be interesting to see if humidity has changed (or rather, the total amount of water vapor - which I presume has increased).

Hi binntho,
here are some plots from the Reanalyzer, it's snow depth, TPW and precipitation. All year.
Snow depth is a bit down, TPW is a bit up.

If you want some specific month or range of months, you can select that.
I checked TPW for October - April also, and it's significantly up, see last attachment. So maybe gives some input to the issue of 'fogginess'.

You can also respecify what area you want to include. Their 'Arctic' goes all the way down to 60 N, but you can choose another latitude as you like.

15
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 17, 2019, 04:05:02 AM »
[ Correction to earlier post:  A while back I threw in a comment that when ice thickness gets below 0.5-0.8 meter it becomes susceptible to flash melt, but that I could not remember the source.  Well, I still can't find it, and looking at ASI thickness data, the greatest one month decline in thickness during melt season (thickness values get skewed by refreezing ice in fall-winter) is less than 0.3m.  So I was wrong.  The annual pattern is about 0.8 to 1.0 meter thickness decline across each entire April to September melt season. ]

-------------------
 I came across some interesting tidbits about ASI thickness at https://nsidc.org/cryosphere/sotc/sea_ice.html

"Using data from submarine cruises, Rothrock and collaborators determined that the mean ice draft (the ice extending below the water surface) at the end of the melt season in the Arctic decreased by about 1.3 meters between the 1950s and the 1990s."

"Examining 42 years of submarine records (1958 to 2000), and a five years of ICESat records (2003 to 2008), the authors determined that mean Arctic sea ice thickness declined from 3.64 meters in 1980 to 1.89 meters in 2008—a decline of 1.75 meters."

(between 2003-2008 and 2010-2012)  "...sea ice volume declined by 4,291 cubic kilometers at the end of summer, and 1,479 cubic kilometers at the end of winter (Laxon et al. 2013)."

They include a chart from Kwok and Rothrock 2009 that shows nearly identical thickness declines of ~50% between 1958-76 and 2003-2007 in different Arctic subregions (Chukchi, Beaufort, Canada Basin, North Pole, Nansen Basin, Eastern Arctic.)   No apparent differentiation between North Pole and the others.

A linear trend line of whole-Arctic September Volume shows a decline from 11.1 to 4.2 M Km3 from 2000 to 2019, a 62% decline

For the CAB volume alone, the decline is from 8.4 to 3.8 M km3, a 55% decline.  So the CAB has lost volume at a slightly slower rate, but not much slower. 

I think this argues against the idea that progression towards a largely ice free September (followed by August, October, July) will be stalled because the final ice refuge is at too high a latitude. 

The Sept. ice is not centered around 90N anyway, but is centered south of 90N on the Greenland/Canadian side.  The location of the remaining Sept. ice does not match bathymetry very well.  So I don't see that as a saving grace either.  I think protection by location matters even less when you factor in the increasing mobility of thinning ice, reduction of land fast ice, and increased open water/wind fetch, and storm potential as Arctic water warms.

Based on all that it seems that the straight line trend for volume (e.g. Stephan, Wipneus) is the best predictor.  If so, then there will be a lot of headlines in 2032 to 2035 as September goes to Zero, followed shortly after by August and October.  I say will instead of "would" because with the lag of the effect on global average temperature from CO2 emissions being at least 10 years (for about half the temperature effect, to ca. 30 years for most of it), the fact that the projected zero monthly ASI volume dates are only 12-15 years away indicates that we already committed to those changes even if we finally got serious about reducing emissions starting in 2020 (which nobody thinks is going to happen in 2020).

The science on how ASI reduction affects weather is still unsettled, but regardless of the details, Jennifer Francis' quote makes a lot of sense ~ How could removing so much Arctic ice NOT affect the weather?

July hitting zero before August in Stephan's table must be a mathematical fluke caused by a slightly steeper decline rate being extrapolated into the future.  On the Wipneus graph, July volume lags about 12 years behind August, which does make sense. 
https://sites.google.com/site/arctischepinguin/home/piomas   


16
Arctic sea ice / Re: "Stupid" Questions :o
« on: December 04, 2019, 02:28:00 PM »
Well said, Binntho.

17
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 12, 2019, 06:11:30 AM »
Well if binntho agrees with me, he must be right! 

    But here is another perspective about a possible Extent pause.  I am (almost) sure that if Tamino bit into the Extent numbers he would, as he did with global average surface temperature faux pause, show that there is no statistical justification for the relatively small number of yearly data points in the presumed Extent hiatus period to be called a significant violation of the long term linear trend that is derived from a much larger set of of data points with considerable year to year variability.  (BTW Tamino's wife announced on his blog that he had surgery recently.  Sending him wishes for healing and good health.) 

    But I submit to the jury that even if Extent did have a statistically valid hiatus, it would not matter.  There could be a scenario where Volume losses continue their inexorable decline, yet a prolonged series of years with conditions favorable for greater ice dispersion resulted in Extent value flat-lining for enough years in sequence to pass a statistical test for truly being a hiatus.   

     But so what?  In terms of progressive ice decline, that would not change the underlying fact that Volume losses were still proceeding toward zero.  A hiatus in Exent would only temporarily increase the discordance between the Extent and Volume trends.  The increased difference would have to be compensated for at the end.  The only consequence of an Extent hiatus would be that the Extent trend would have to fall that much farther faster when the zero Volume-Thickness-Extent day of no ice reckoning finally arrived. 

    The 10-30 year lag for the majority of global warming impact from elevated greenhouse gas levels to be expressed means that the warming and ice melt trends for the next 10-30 years have already largely been set by our previous emissions.  The fact that the trend-projected date for the first zero ASI Volume event is now within the next 20 years means that it is probably unavoidable at this point even if we sharply reduced further GHG additions.  Then again, Notz and Stroeve point to an 800 Gt CO2 of additional emissions needed after 2018 for the total GHG load to be enough to result in Volume reaching zero.  So in theory at least, keeping total emissions below that amount could presumably prevent the Volume losses from reaching the zero point. 

     (On the other other hand, --- running out of hands ---, I suspect that even if emissions ceased immediately, with enough time and the slow depletion of existing CO2 from the atmosphere, even the GHG emissions already made thus far, bolstered by some permafrost thaw and other feedbacks, would eventually result in ASI Volume-Thickness-Extent reaching zero.)

     That is a moot point for the real world situation.  It does not seem at all likely that humans will cut emissions sharply enough and soon enough to prevent exceeding the 800 additional Gt CO2 after late 2018 threshold.  And therefore, assuming the Notz and Stroeve relationship between total CO2 emissions and ASI Volume is correct, the Extent trend will meet up with the Volume trend at the zero point.  Which year that happens depends on how fast we move towards that 800 Gt CO2 post 2018 threshold.  This being the end of 2019, we have probably reduced the remaining budget to 760 already. 

     Extent can go where it will prior to the zero day of reckoning, but when the Volume trend reaches the point where there is no ice to spread around, Extent will also be at zero.

   Edited quote
And we already know that volume is falling faster than extent, which means that thickness is falling faster than extent.
    I don't agree with the second part, "... which means that thickness is falling faster than extent. " 
    Yes, we know that Volume is falling faster than Extent.  Because Volume is the product of Extent x Thickness, Volume has to fall faster than Extent unless there is either Thickness gain or zero loss.  But Thickness does not have to fall faster than Extent for Volume loss to be less than Extent loss.  It does not matter which of two (Extent or Thickness loss) is greater, or if they are exactly equal, all that matters is the product of Extent x Thickness, because that is what defines Volume.

   

18
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: November 07, 2019, 07:50:05 PM »
I took the monthly extent value for October 2019 and added it into my long-term plot where I calculate the anomalies from 1979 up to now.
The average October extent is now 7,98 M km². October 2019 had an average extent of 5,67 M km², which is 2,31 M km² less than that average and the lowest ever recorded since 1979 and the only October with an average value which is smaller than the average minus 2 standard deviations.
This low level also let the blue curve dip deeper below the red long term linear trend line. It is lower now by -1,10 M km² (calculated from the trend line this October should have been at 6,77 M km²).
The slope of the overall trend line has decreased by four digits compared to September 2019.

See attached graph.

19
Arctic sea ice / Re: Arctic Image of the Day
« on: October 08, 2019, 01:02:32 PM »
Here is a timelapse I made 9 years ago. The quality is not much to cheer for, but the movie has its moments.

20
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: October 06, 2019, 12:23:29 PM »
Yesterday was my birthday. 18 again.
Normal service will be gradually resumed as my hangover dissipates

21
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: September 16, 2019, 02:22:14 AM »
Hi everyone:

We are celebrating the Independence of México, so I will not be posting today.
Having fun with friends.  :)

If someone else makes the post. Thanks!

https://ads.nipr.ac.jp/vishop/#/extent

22
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 09, 2019, 11:21:43 PM »
      And since I am pontificating on statistics, here are some take away messages from the recent graphical posts by Oren, binntho, Archimid and El Cid (and thanks to all).

RE binntho's Extent and Area straight line trend
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227604.html#msg227604
     While it certainly looks like a significant downward trend, you can't say the slope is different from zero without doing the stats.  It probably is, but your use of the visual assessment method is no more valid than it is for the folks arguing that the process has stalled because it looks that way in the last 10-13 years (again I am shameless, the same applies to me too, my sinful nature was noted in previous post.  We are all fallen creatures.)

RE Oren's CAB volume trend and thickness graph
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227570.html#msg227570
    That's almost the chart I was hoping for, but it would be even better with a straight line regression trendline, tested for difference from zero, and then extended out 20 years to 2040.  FWIW, if you squint and draw a straight line through the CAB volume trend for Day 243, aka end of melt season, the slope of that line will indicate about 4 million km3 decline from 2000 to 2019, i.e. 19 years.  If that trend continues, then take another 4M km3 over next 19 years and it reaches zero in ca. 2038.  That's only a few years later than the Wipneus straight line projection of sea ice volume trend for the entire Arctic.

    The key characteristic about Oren's chart is that it is limited to ice volume in the CAB.  Thus, it presumably removes possible inflation of losses by peripheral seas that are melting out sooner than the CAB.  What started this phase of the discussion was the notion that future loss rate would decline because the CAB would be more resistant to melting.  I think the Oren chart refutes that. 

     I was surprised how strongly negative the CAB end-of-melt-season (i.e. annual minimum, day 243 data) volume is.  The CAB may look like it's been hanging on, but apparently that is the deceptive Extent curve at work.  The CAB has been rotting out from the inside.  As for the future, the presence of ice in the peripheral seas late into the summer might have reduced past losses in CAB.  Their presence has kept Arctic Ocean albedo high and almost certainly reduced pack rotation and transport out through the Farm Strait (and thanks to Tor for insight on importance of  export losses).  With less protection from ice in those peripheral seas as they melt out earlier in the year, the rate of CAB losses could markedly increase in the future. 

   Archimd's graph shows that CAB volume losses appear to already be increasing https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227455.html#msg227455.

     In addition,  the wider amplitude of the fluctuations in El Cid's graph
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227470.html#msg227470 gives me a bit of the willies because one of the predictors for a nonlinear chaotic system reaching a tipping point is higher variability.  I may be misapplying that concept because max to min amplitude is not the same as variability between years, but I allow myself my own superstitions.

    But 2038 as the projected zero year for CAB sea ice volume is over a century earlier than binntho's trend extension showing Extent not reaching zero until 2187. How can that be?   Extent is not declining as fast as volume because the remaining volume is being contained in thinner and thinner ice, and thus the Extent does not decline as much as it would if thickness remained constant.  But as the thinnest ice contributing to Extent reaches zero thickness, it stops contributing to the Extent number.  In the end, the Extent curve and the Volume curves have to meet because zero volume provides zero ice for Extent.

    Which brings me back to Oren's thickness graph.  Total conjecture, but my guess is that once average thickness gets below 1 meter we will start to see the end-of-melt-season Extent curve start catching up with its parent Volume curve.  Ice melting comments elsewhere on ASIF point to the much lower melt resistance of thin vs thick ice.  Regardless of my conjecture, the Extent curve HAS to catch up to the Volume curve eventually.

    Stay tuned.  I think there are wild times ahead for ASI in the very near future because it is on the edge of the precipice.  It will be entertaining for those of us who like to watch numerical systems evolve.  Too bad it isn't just a horse race or some other innocuous event, but is instead the loss of a crucial component for meteorological and climatic stability on the only planet in the universe known to host self-aware, so-called "intelligent" life (actually any life, but I think we will soon see that microbes are just about as common as water).  As my brother, a conservative who bought into the climate hoax BS for a while, but who is too smart to stay ignorant, said when he came to see the big picture: "This story does not end well".

   

23
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 09, 2019, 11:12:32 PM »
    Folks - we don't need to go around the wheel again about whether the recent apparent flat lining in annual minimum Extent and Area is real or not. (I don't think anyone is arguing that volume has flat lined).  Yes it looks like the trend has flattened out in recent years, and maybe it has.  The point is that given the degree of inter-annual variability between individual data points (i.e. years), the paucity of data points does not provide support for the assertion of a change in long term trend with any acceptable degree of statistical certainty (i.e. less than 5% or even 20% chance of a Type I false assertion error). 

     That said, just drawing a straight line trend through the 1979-2018 Extent data that looks like it points down is not a statistically based conclusion either.  But just from an eyeball view I bet it is significant.  (I know, I know, the hypocrisy is astounding!)  I admit I didn't actually run the tests, I'm too lazy and not enough time to do so, but Tamino has already covered this ground with far more skill than I could.
   
    Tamino has addressed the parallel issue of the so-called pause in global surface temperature warming after the El Nino driven high value in 1998.  I think that controversy is exactly analogous to this discussion about a possible flattening of the ASI Extent trend.
https://tamino.wordpress.com/?s=pause

    One of the best of those blog articles also discuss the same phenomenon at play with ASI https://tamino.wordpress.com/2019/01/07/fooled-by-noise/

   Appearances can be deceiving with noisy data.  As for rolling the dice 13 times, I think that is a false analogy due to the multiple testing problem. Again, see Tamino.

   The ice doesn't care what any of us think it's doing anyway, so let's just wait and see.  But that takes years, and inquiring minds want to know now, so here is a pseudo-answer. 

   I will bet the price of a lifetime subscription to the ASIF that the average of the 2019-2021 ASI Extent, Area, and Volume will each be less than the average of their respective values in 2016-2018.  Even with a statistically significant downward long-term trend, short term noise could lose that bet for me, but I don't think so.  I think too much damage has already been done, with more on the way. I agree with others who have noted that the remaining ice "doesn't look good".

   

24
Arctic sea ice / Re: The 2019 melting season
« on: September 09, 2019, 03:14:10 PM »
Problem solved! I will be posting my Nullschool graphics here from now on. Feel free to post your own!

https://forum.arctic-sea-ice.net/index.php/topic,2905.0.html

25
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 08, 2019, 09:48:32 AM »
There is a regional daily volume file published by Wipneus on the PIOMAS thread every time the data is updated. I can make a chart tomorrow if no one else posts it by then.

26
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 07, 2019, 05:31:51 PM »
yes an arm continues in existance but not hugely significant?

I guess not.

Crandles, are we nudging towards an FFA?
Whatever you lot are going to agree about,
I have been disagreeing,
I am disagreeing,
I will disagree,
I will have disagreed.

27
Arctic sea ice / Re: The 2019 melting season
« on: September 07, 2019, 02:23:43 PM »
Perhaps a new poll - Which Will Happen First: BOE or FFA?

(FFA: Full Forum Agreement)

I’d love to see the first, hate to see the second.

28
Arctic sea ice / Re: The 2019 melting season
« on: September 06, 2019, 10:48:20 AM »
That's a low pressure system so it causes dispersion -- the opposite of compaction.

On your figure, I suggest you redraw your arrows at 45 degrees to the right of the actual wind directions displayed -- which is the direction the ice goes (Coriolis) -- and then you will see the dispersion.

It's pretty trippy how a low-pressure system which should intuitively drag stuff inwards to fill the void, actually ends up pushing things away instead.
It actually isn't... A low pressure system creates a bulge on the ocean surface, so ice would have to travel up a slope to get to the center of that bulge. High pressure systems create a dent in the ocean surface, so the ice falls into that pit towards the center...

I'm pretty sure this is completely inaccurate, but can there be some truth to this?


Try reading this article about Ekman Transport https://en.wikipedia.org/wiki/Ekman_transport

Movements on a spinning sphere aren't always intuitive
Thank you Glenn, I will certainly look at that! It was on my to do list...

I can't really visualize this. If gravity could move the ice down the slope, it would simply even out the water bulge as well.
I actually started writing that down as a joke, but then started wondering if there could be some truth to this. But mainly, I was joking, because the wind would of course have a much bigger impact on the ice than gravity.

29
The rest / Re: Is Man the "Unnatural Animal?"
« on: September 06, 2019, 10:46:11 AM »
Again, completely agree with wdmn and binntho.
Even the "Mule" in Asimov trilogy was natural. Evolution is constantly coming out with billions of new outputs, those better adapted to their environment will have better chances of reproduction. Is not that difficult.

30
The rest / Re: Is Man the "Unnatural Animal?"
« on: September 05, 2019, 04:56:47 PM »
    Time and space are but one illusion
    Without that truth there is much confusuon .. b.c.

31
The rest / Re: Is Man the "Unnatural Animal?"
« on: September 05, 2019, 01:17:20 PM »
Quote"This is typical (human) group behaviour in all agricultura societies which really just proves the point: Individuals make choices, group behaviour is controlled by underlying forces that we are unable to control.

Therefore this path of development is not something that was chosen by any individual, nor was it chosen by the group (since the group can't choose). This becomes even clearer when you consider that no individual ever took a conscious decision to start this process, there was nobody who saw what the outcome would be and there was no planning involved. It just happened."


Totally agree!

32
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 04, 2019, 05:01:20 PM »
Yes, some will only see what they want to see.

I wonder if this is a projection.  ;D

33
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 03, 2019, 08:55:37 PM »
I had another look at my 365 Day trailing Averages, i.e. the continuous trend in average annual sea ice over the years.

I don't see how anyone can say that sea ice is not declining. And this concentration on the minimum - one day in the 365 day year, seems designed to ensure lack of light.

ps: When the area & volume lines cross, average thickness for the whole year will be less than 1 metre.

34
Arctic sea ice / Re: Basic questions about melting physics
« on: August 31, 2019, 05:37:04 PM »
Your second reply completely invalidates his conclusion with a very appropriate language and tone. Thank you for that great reply and thank you for proving me wrong.

35
The rest / Re: Are you hoping for a global civilisational collapse?
« on: August 27, 2019, 10:07:41 AM »
Is there somebody with higher authority than me who could be bothered to make those changes (i.e. add multiple choice and / or allow voters to change their votes).

I've done the latter.

36
The rest / Re: Are you hoping for a global civilisational collapse?
« on: August 27, 2019, 08:28:48 AM »
back to the question:

It seems to me that many people who post here have a secret death-wish, a desire for an all-out culling that would lead away from the rotten, dirty present and destroy this evil civilization: a Ragnarök as said above. This theme is as old as mankind. I am surprised though that how many seem to subscribe to it...

37
Arctic sea ice / Re: Are you hoping to witness a BOE?
« on: August 26, 2019, 08:19:45 PM »
The poll was great. I voted ASAP to raise political awareness, as for the effects I think we are starting to feel it.
Thank you all.
This thread has become an outlet for cheap philosophical messages. I’ ll try to close it now

38
Arctic sea ice / Re: What's new in the Arctic ?
« on: August 26, 2019, 11:38:56 AM »
Santa Claus maintains the sign.  (duh!)  ::)

Here's the evidence:

39
Arctic sea ice / Re: Arctic Image of the Day
« on: August 23, 2019, 07:24:24 PM »
Puffy clouds perfectly illuminated from the side over Franklin Island.

#hach

40
Arctic sea ice / Re: "Stupid" Questions :o
« on: August 12, 2019, 06:24:26 PM »
Maybe we need an 'endless discussions thread'?  ;)

41
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: August 04, 2019, 02:18:25 PM »
The question of this thread has been answered. DMI has the arctic ice free today.  ;)

https://web.archive.org/web/20190804121548/http://ocean.dmi.dk/arctic/icedrift_anim/index.php

42
Arctic sea ice / Re: The 2019 melting season
« on: July 29, 2019, 04:43:04 PM »
This post started from the ice-drift map (latest attached) and a stray image in my mind. Wind will have very little traction blowing over a flat 100% concentration ice pack (until it hits a pressure ridge). But on a load of ice rubble?

So in an attempt to do something about my total ignorance I googled and found two papers produced in 2014 from a National Science Foundation project..

https://www.arcus.org/witness-the-arctic/2014/3/article/22794
Arctic Ocean Sea Ice Loss: Modeling the effect on Wind-to-Ocean Momentum Transfer
&
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013JC009425%4010.1002/%28ISSN%292169-9291.FAMOS1
Seasonality and long-term trend of Arctic Ocean surface stress in a model

Most of the remarks below are from the first - written so even I could understand (most) of it.
Quote
The momentum flux from the atmosphere into the ocean (also known as ocean surface stress) depends on various factors such as wind speed, surface layer stability, surface roughness, and sea ice conditions. Roughness changes in response to changing ocean surface waves and variations in the geometry of ice floes and ridges. Three regimes characterize how sea ice moderates momentum transfer into the Arctic Ocean:

    1. At very high ice concentrations, near 100%, the pack ice is so compact that it barely responds to the wind forcing and hence also shields the ocean from the wind.

    2. Slightly lower ice concentrations, about 80-90%, allow the ice to drift freely with the wind as pressure within the ice pack is reduced to a minimum, while floe edges and ridges provide high drag (See Figure 1). We refer to this as an "optimal ice concentration", because ocean surface stress is maximal in this case -- as illustrated in the graph of ocean surface stress as a function of sea ice concentration derived from Pan-Arctic Ice Ocean Modeling and Assimilation System1 (PIOMAS) output (See Figure 2).

    3. For still lower ice concentrations, stresses decline because open water—even with surface waves—is generally smoother than pack ice.
graph attached
This suggests to me that when looking at the ice drift map the effect of winds will be highest in the high concentration (but less than 100%) areas


Quote
a shrinking summer sea ice extent means less momentum flux into the ocean in this season. How is that? In the 1980s and 1990s most of the Arctic Ocean featured high ice concentrations, even in summer, with an average close to the 80-90% optimum.

In recent years however, vast areas of open water have reduced the mean ice concentration below this optimum, which results in an overall ocean stress decrease at a small but significant rate in summer.

What does the future hold? The area of high momentum flux (See green in Figure 3a) is shrinking toward Greenland as sea ice continues to retreat. Further, an expanding summer season with increasingly less ice coverage might steepen the negative ocean stress trend and eventually even reverse the positive trends in spring and fall. But this assumes that wind forcing and ocean surface waves do not grow, an assumption that might prove incorrect in a changing climate. This illustrates the fascinating interplay between opposing forces that will determine the magnitude of Arctic Ocean currents in the future.
image attached


The second paper shows show how while in summer ocean stress trend is falling, in spring and especially autumn (period of highest winds is in October) ocean stress is increasing as concentrations in much of the remaining ice have fallen to below 100%.
See last image, and here is their conclusion (edited)
Quote
Our analysis indicates that sea ice in free-drift amplifies the momentum transfer from the atmosphere into the ocean, which contradicts the general perception that sea ice damps the atmosphere-ocean exchange.

On annual average, most momentum is transferred at an ice concentration of 85%.

On the seasonal scale, sea ice conditions are optimal for maximal momentum flux into the ocean twice a year, in spring and fall. However, wind speeds are much higher in fall

What do I take from this?
- when looking at a sea-ice drift / wind speed map, have the Bremen ice concentration map to hand to see where he biggest impact will be on ice mobility (green and purple not good, yellow and red good?,
- October is the month when winds can have the maximum effect on a weakened ice pack (also Spring?),
- the data goes to 2012. Were there follow-up projects?   I hope so.
___________________________________________________________
I think this is relevant to the end of season prognosis.
I await being shot down with interest.

43
Rich, I am normally quite tolerant, and even more so towards new members. But I have been convinced there is a problem with some of your posts, and it's not about their content but about their tone. When you keep on arguing to the point of derailment due to overconfidence, when you relate to other posters as cult members, when you paint yourself as a martyr, and other examples too numerous to count, you piss people off and create dissension. I have no problem with claims of low or high momentum, this or that end if season forecast, and so on. In fact I often agree with your core content. But I still get pissed off, reading page after page of dissension which somehow involves you.

I think some humility would help fix things. It's not about you, it's about the science. Chill off. Don't take everything so personal. When you say something and are immediately told you are wrong by multiple posters, you probably are wrong. Take it to lightweight threads, go read source material (Wikipedia is often strong on the basic science but simple enough to.understand), rather than fight it out in high-rating threads. When given insults, ignore and move on, rather than insulting back. And avoid general attacks such as "cult" and so on. Humility and hard science are the proper tools here.

44
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 25, 2019, 10:23:54 AM »
why does the dutch word ijsberg translate to iceberg while a regular "berg" (made out of rock) is a mountain or hill ?

Mountain derives from old French and ofc we do not have real mountains so when we talk about the ´bergen in the alpen´ we talk about their montagne/mountains.

We did have a lot of ship so somehow the iceberg is derived from dutch but the word root is similar for danish and norwegian so basically it is derived from that language group  in about the 19th century. (It would be cool if we had an online database where we could jump to the actual articles and books the word starts appearing in at the time, or at least a list of names of those and the authors).

https://www.etymonline.com/word/iceberg

BTW no one would translate it as ´klif´ but that is because we lump all that exotic stuff. Van de Berg is a common dutch name so we use it for small humps.

45
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 25, 2019, 06:57:47 AM »
Folks, this thread is deteriorating fast and hard.
Sometimes the best answer is to keep mum, and let things sort themselves out. Not every post needs a riposte.
The arctic will go BOE in a decade and a half (this was the subject of this thread, not the consequences BTW) and then we can revisit and see who was right.

46
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 15, 2019, 03:15:13 PM »

At this point I'm trying to keep it as simple as possible and isolate the variables. Perhaps it's incorrect, but I'm working with an assumption of 1 layer in 10m deep coastal water.

Sounds reasonable to me, as long as there's a little wind and/or waves.  But even this would be seasonally variable.  In freezing season, salt is excluded from the forming ice, and sinks to the bottom.  In melting season, melting ice releases fresh water, which floats above the saltier water below.  Still, in 10 meters of depth, it won't take much wind or waves to mix the whole column of water, once the surface ice is gone or pulverized.

We have very little data for depth/salinity/temperature plots on the Russian side of the arctic.  The few buoys we periodically discuss here all get placed on the US/Canadian side.

For the submerged permafrost, degradation will be slow, because heat from the ocean waters above hasn't a strong tendency to move down--heat rises.  At the bottom surface of the submerged permafrost geothermal heat is quite weak, as the permafrost layer is insulated from the geothermal heat by great depths of ancient sediment.

It works a little differently between land and marine permafrost degradation.  Freshwater lakes tend to have a temp of +4 degrees C at the bottom, because that's the temp at which fresh water is densest. These "thermokarst" lakes keep melting permafrost at their bottoms.  This is not the case for seawater, which is densest at about its freezing point. 

So melting of submerged permafrost will be very slow.  But I think it's effectively impossible for submerged permafrost to grow in depth, it can only thin and degrade over time.  Like, apparently, thousands of years.  Of course, the submerged permafrost has had something like 10k years to get along on the process since the last glacial maximum.

Shakhova and Semiletov have published voluminously on arctic permafrost.  I've only skimmed a few of their articles.  So if you want *real* expert information, I'd suggest perhaps starting here:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C21&q=Shakhova+Semiletov

47
Arctic sea ice / Re: The Rammb Slider Thread
« on: July 14, 2019, 11:37:48 AM »
 Appreciate your interest binntho, as b_lumenkraft mentioned there are likely several/many factors at play.  I'm certainly no expert, but the the counter clockwise motion to me suggests there is some upwelling.  I'm basing this on how the atmosphere works, low pressure is associated with rising air. 
  With so little open water, wind stresses seem to be minimal, but perhaps a southerly flow over the land masses of the CAA *could* result in modest coastal upwelling.
  The most mysterious question to me, is whether these exist under the ice, or do they form only due to the opening.  I haven't a clue.  It'll be interesting to see how they behave going forward.
   I think features like this emphasize the value of these sub daily images available from RAMMB, and am grateful that others, especially b_lumenkraft, have also taken an interest.

48
Arctic sea ice / Re: The 2019 melting season
« on: July 11, 2019, 12:22:38 AM »
Hello, hope this fits topic. A 100-day long journey of a floe. Very resilient one - all her neighbors, even bigger ones and more in the back on the start line, are in shambles already. She's alone now reaching another coast, a roasting one this time.
Where's her finish line?

14MB gif (hope it will work well) with 30sec loop, you can look at other floes in next loops, but don't waste more than 10 minutes on this.  ;)

49
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 05, 2019, 09:22:02 PM »
Can we all agree that surface water on sea ice can disappear for a variety of reasons?

(Stakes out argument with every nincompoop on the thread.)  ;)

50
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 05, 2019, 01:32:19 PM »

I agree with all of that. However, that's most unsatisfactory, as I'd like to have an argument:

Are you sure you'd like an argument, or simply contradiction? The latter happens a lot on some of the threads of the ASIF.
____________________________________
M: An argument isn't just contradiction.

O: Well! it CAN be!

M: No it can't!

M: An argument is a connected series of statements intended to establish a proposition.

O: No it isn't!

M: Yes it is! 'tisn't just contradiction.

O: Look, if I *argue* with you, I must take up a contrary position!

M: Yes but it isn't just saying 'no it isn't'.

O: Yes it is!

M: No it isn't!

O: Yes it is!

M: No it isn't!

O: Yes it is!

M: No it ISN'T! Argument is an intellectual process. Contradiction is just the automatic gainsaying of anything the other person says.

O: It is NOT!
___________________________________________________________

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