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Messages - Glen Koehler

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1
Arctic sea ice / Re: What's new in the Arctic ?
« on: January 07, 2021, 04:10:53 PM »
The end-game begins through the Nares Strait?

"Ice arches holding Arctic's 'last ice area' in place are at risk, researcher says"
https://phys.org/news/2021-01-ice-arches-arctic-area.html

Excerpts  -------
But recent research at the University of Toronto Mississauga suggests the last ice area may be in more peril than previously thought. In a recent paper published in the journal Nature Communications, Professor Kent Moore and his co-authors describe how this multi-year ice is at risk not just of melting in place, but of floating southward into warmer regions. This, in turn, would create an "ice deficit" and hasten the disappearance of the last ice area.

"The last ice area is losing ice mass at twice the rate of the entire Arctic," Moore says. "We realized this area may not be as stable as people think."

His most recent analysis of satellite data says the problem may be getting even worse. The arches along Nares Strait that historically have held the Last ice Area in place have become less stable, according to the study.

"The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of Arctic Ocean multi-year sea ice," he and his authors write.

Ice arches only form for part of the year. When they break up in the spring, ice moves more freely down the Nares Strait. And that breakup is happening sooner than in the past.

"Every year, the reduction in duration is about one week," (emphasis added by GK) Moore says. "They used to persist for about 200 days and now they're persisting for about 150 days. There's quite a remarkable reduction.

"We think that it's related to the fact the ice is just thinner and thinner ice is less stable."

More information: G. W. K. Moore et al. Anomalous collapses of Nares Strait ice arches leads to enhanced export of Arctic sea ice, Nature Communications (2021). DOI: 10.1038/s41467-020-20314-w

2
Arctic sea ice / Re: The 2020/2021 freezing season
« on: December 29, 2020, 06:01:50 PM »
    Nice video A-Team.  That view makes me wonder if Nares export could become much more important in the next few years.  If open, it provides an exit route for what little remains of MYI.
 
    The Lincoln Sea ice does not look all that solid especially for this time of year.  While additional freeze will occur between now and March-April, does the animation provide any hint about how solid the Lincoln Sea ice is likely to be heading into the 2021 melt season relative to recent historical average condition?  And does my speculation about the degree of Lincoln Sea "solidity" having an effect on Nares export, and consequently also on the longevity of the heart of the remaining MYI, make any sense?  Maybe this belongs in the Stupid questions thread, but also useful to post it just below the animation to see what I'm referring to.  (note to others -- you need to double click to see the video in whole-screen mode).   The recurring mega-crack north of Greenland seems like it could be another important contributing factor to this scenario.

3
Arctic sea ice / Re: What's new in the Arctic ?
« on: December 22, 2020, 06:54:05 PM »
Killer whales expanding their hunting area by taking advantage of Arcitc sea ice reduction

    Even if you aren't interested in the biological story, the scale and stark beauty of the scenery makes it worth watching.

4
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 18, 2020, 11:55:37 PM »
To get back to the Convergence question:
      The hypothesis is that the number of years remaining until the zero ice date estimated by the Extent trend will decrease relative to the date estimated by Volume as we get closer to that date.
The hypothesis says that until they meet when both Volume and Extent trends reach zero, it is the Extent date that will shift to meet the earlier Volume date, not vice versa.

      Here are the relative zero date migrations for 1979-2008 vs. 1979-2020 for each month.
The values for Extent and Volume are the number of years earlier the end date became by adding 2009-2020 to the 1979-2008 dataset.

      By subtracting the Volume shift from the Extent shift, a Positive value means that the Extent estimate moved earlier by a greater amount, which is what the hypothesis predicts.  A negative difference means the opposite, that instead of drawing closer to the Volume-based estimate, the Extent-based estimate is moving away from it. 

Jan: -2 (for Extent) minus 13 (for Volume) = -15 
    The Vol. estimate got 13 years earlier, but Extent est. became later not earlier, and thus farther away from the Vol estimate.  This is the opposite of convergence and NOT what the hypothesis predicts.

Feb:   12 minus 15 =  -3
Mar: -22 minus 15 = -37 
Apr: -45 minus 15 = -60  (Wow, Ext estimate became 45 years LATER).
May:   6 minus 19 = -19
Jun:  21 minus 20 =    1
Jul:   24 minus 15 =    9
Aug: 20 minus 11 =    9
Sep: 13 minus 14 =   -1
Oct:  30 minus 9  =   21
Nov: 27 minus 11 =  18
Dec:   4 minus 10 =  -6 

      As you noted, the winter and spring months are doing the opposite of convergence.  While summer and fall are generally showing convergence.  That makes sense in that we would expect the "thin ice" months to show convergence between Extent and Volume before the "thick ice" months.  It is when thickness reaches a critical low threshold that Extent losses increase causing it to begin to catch up to Volume.

      June being a neutral month with respect to the "Extent trend must bend down to catch Volume trend" hypothesis makes sense because it is the transition between the thick ice and the thin ice months.

      But September is a brain twister.  It seems like it should show a full expression of the 'Extent catches Volume as ice thins' trend.  My guess is that those bays in the CAA and other ice traps that are the reason for setting the BOE definition at 1M km2 of residual Extent instead of zero, are already constraining reduction in September Extent.  Those areas may be superficial thin ice that add to the Sept. Extent value without adding much to the Sept Volume because they are so thin.  As a result, the Sept. Extent value does not decline as much as it "should", but Sept. Volume does not as effectively hide the loss of ice.

      It is also a bit mysterious to see the peak "thick ice" months going the opposite direction, i.e. the Extent-trend zero date is getting farther away not closer to the Volume date.  And for March and April, the zero Extent estimate is getting absolutely later, not just getting earlier at a slower rate than the Volume date. 

      My guess is that happens because once the Arctic Ocean fills up with ice, it is full.  Even in the colder, higher ice volume past, it could not add more Extent because the Arctic Ocean is surrounded by land.   These days, the ice Extent comes from thinner low-volume ice, but that change is not reflected in the Extent value.  It still counts for Extent.  The March and April constraint on Extent in the past means that as the ice declines now, relative to the previous years, March and April don't show much if any Extent loss.  So as more years are added to the dataset, with little change in the constrained monthly Extent values for March and April, the trend towards a Zero Extent date for those months is essentially no trend at all with termination dates over 300 years from now vs. decades for the other months. 

      Actually, that point applies to ALL of the maximum ice months of January through May.  For each of them, the zero Extent year estimate is past 2300, and for Feb-May, in the late 2300s.  Thus the negative trend slope is so minor that there really isn't much trend at all due to the constraint on maximum Extent in earlier years.

      The "land bound Arctic Sea Ice" argument conveniently ignores the potential for additional Extent in the peripheral seas not bound by the coast of the Arctic Ocean.  Are your Extent and Volume data for the entire Arctic, including the peripheral seas, or are they limited to the (mostly land bound) central Arctic Ocean?

      If the data are limited to the central Arctic, then I don't have to explain away that potential for additional Extent.  But if your data also include those peripheral areas (Greenland, Okhotsk, Bering Seas) that the "land bound Arctic Ocean" argument does not address, I won't even attempt to concoct some reason to explain them away as I have already used up my daily allowance for fabricating "evidence".

5
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 18, 2020, 10:27:43 PM »
Dear Stephan - Nice work and much appreciated.  I think that this addition to your monthly trend posts really gets to the heart of the issue.

       Everybody else - especially Arctic amateurs like me:  Take enough time to understand what these numbers are saying.  What may appear at first glance may appear to be an innocuous table of numbers, in truth says major and disturbing things about the future of the Arctic, this planet, humanity in general, and the not-very-distant future for each us individually and the people we love.

    1) Lots of talk by IPCC and elsewhere about sea level rise by 2100.  No disagreement with that, it is a huge impactful manifestation of our insane management of the planetary life support system.  But also consider what it means to have ZERO Arctic sea ice volume in June, the month of maximum solar energy injection, by 2067.  Moreover, that the date for that catastrophic milestone gets 20 years earlier when you add 12 years to the straight-line trend to go from 1979-2008 to 1979-2020.  Will adding another 12 years, i.e. 1979-2032 put that date at 2047? 
       A planet without its reflective polar cap in June is a different planet than the one we were born on.

    2)  If 2047-2067 is too far off to get your interest, how about 2032-2035?  And what about 2026?  Is that close enough to get your attention as being real?

        ZERO Arctic Sea in August - October is also a radically different planet. While far below June, there is still considerable solar energy input in August.  And an ice-free Arctic Ocean in October (and with much reduced ice in November) venting heat into the atmosphere is bound to have strong effects on mid-latitude weather patterns. 

        The table highlights the fact that adding 12 years to the dataset used to define the trend pushes the zero volume dates 9-14 years earlier.  2032-2035 is already close at hand, but will those trend endpoints continue to get earlier as each new year is added?  Where will those endpoint dates be in just 6 more years in December 2026?  The "trend of the trends" suggests that the estimated ice-free Sept date by then could be another six years earlier, i.e. 2026.  At risk of piling extrapolations on top of each other, does that suggest that we could already have had a zero-ice September by then?

        One of the problems in conceptualizing climate change is that the perceived impacts are in the future.  People already dealing with wildfires, heat waves, droughts, hurricanes, crop failures etc. will have a more immediate perspective, but for many/most of us, the climate changes that worry us are said to be decades ahead and so bring a bit less visceral fear. 

        The dates shown for zero ice volume are nothing new to me, so I've long had the mental concern.  And perhaps I am misinterpreting and over-reacting to seeing the earlier progression of endpoint dates that result from adding 12 years to the dataset.  But my visceral fear just went up.  My emotional operating principle has been that the proverbial poop could hit the fan if global average surface temperature reaches +1.5C over preindustrial circa 2030.
 
       I keep thinking that my understanding of climate change and Arctic Sea Ice decline has reached a level of stability at which I can at least see the horror for what it is, and at least define the problem.  But the damn problem keeps growing like a cancerous tumor.  Seeing that date migration of the Sept. zero ice year has me wondering if I should recalibrate my gut-level fear threshold and "poop in the fan" date more towards August 2026 - less than 68 months from now. 

       Of course, ranting aside, the "Now" is all that we can change to affect the Future.  I hope your data serves as that one additional piece of alarming evidence that tips the scales to wake up the political and business powers to realize that the money won't do any good if there is not a livable planet on which to spend it.  Sorry for such a bleak message as we head into the traditional western holiday season.  I would highlight the fact that some good things are also underway, but this message is already long.  So yes, there are also some good possibilities emerging.  We MUST make those possibilities real.

6
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 16, 2020, 05:49:57 PM »
    Thanks for tracking the data Stephan. 

    I don't expect the "Great Convergence" between Extent and Volume trends until closer to the endpoint as Volume gets below about 0.8 km3 and when the average thickness is below 0.8 meter.  But you mentioned that the Ext and Vol trends are already converging. 

     Do you have a record over recent years of the difference between the extrapolated zero-year estimates for Extent and Volume trends?  That would be interesting to see, and would correct the mistaken (IMHO) assumption by some who think the Extent trend is an accurate predictor for the first, and then regular, BOE status in Septembers.   

     My view is that Vol. dictates Ext., not vice versa.  And that as Thickness declines there will be an acceleration of Extent decline until it catches up to Volume at zero.  Thus, first <1m km2 Extent BOE around 2030 or earlier, not around 2060 as estimated from extrapolation of the Extent trend.  Multiple other correlated indicators such as global average surface temperature and cumulative atmospheric CO2 ppm also point to BOE status being reached around the same time as the Volume trend estimate. 

     The problem with Extent, as noted in JC Garcia's tagline, is that Extent alone hides about half of the ice losses because it does not account for simultaneous Thickness reduction.

7
    RE: 2020 global average surface temperature.
    Hansen speaks.  All should listen.  Excerpt below.  Full message at     http://www.columbia.edu/~jeh1/mailings/2020/20201214_GlobalWarmingAcceleration.pdf

8
Arctic sea ice / Re: What's new in the Arctic ?
« on: December 09, 2020, 12:22:08 AM »
2020 Arctic Report Card summary --
The Arctic is getting hotter, greener and less icy much faster than expected, report finds
https://www.cnn.com/2020/12/08/weather/noaa-arctic-report-card-2020-climate-change/index.html

Inside Climate News version
https://insideclimatenews.org/news/08122020/annual-report-card-marks-another-disastrous-year-for-the-arctic/

Edit - The Arctic Report Card 2020 is online, with a summary at
https://www.arctic.noaa.gov/Report-Card/Report-Card-2020

9
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 02, 2020, 01:50:18 AM »
     FWIW - don't bother with the first two videos (esp. #2 which is mostly self-promotion of his web/Facebook stuff).  You won't miss anything by skipping #1 and #2, because the same points get repeated and then repeated again when he actually gets to reading the journal article to you in video 3. 

     If it sounds like I'm ragging on Beckwith, I am.  I lost confidence in him a few years ago when he made what other sources indicated was an incorrect alarming claim about jet stream activity.  (I don't know enough to judge, just comparing sources).  I do appreciate Tom for posting this and Beckwith for bringing attention to what appears to be an important, though not necessarily as definitive as implied, study and conclusions.  To their credit, the authors say "It should be noted that this application of EOF analysis reveals statistical relationships only, and future research will require targeted modeling experiments to verify causal mechanisms."  Whereas, Beckwith makes it sound like he has found the missing link that explains all.  (And BTW, Jennifer Francis rocks!)  You can read the article to yourself via open access at https://iopscience.iop.org/article/10.1088/1748-9326/abc047/pdf

     Maybe I should just appreciate anybody that brings attention to the climate crisis, but IMHO Beckwith is not the most accurate or reliable source and his commercializing the catastrophe is offputting. 

10
I am not sure these seasonal forecasts are good for anything....
If you are right about that, that's an awful lot of highly skilled time...wasted...

     A couple of years ago I did some home-brew testing of the skill of  short-term and "seasonal" (=3 month groupings) forecasts for temperature and precipitation.  The criterion was how much improvement the forecasts/outlooks provided compared to a simple climatology estimate as to whether the period would be in the upper, middle, or lower third relative to <edit> the 30 year historical average the ca. 100 years in the historical record.  Thus the climatology estimate was a 33.3% chance of each.  A 10% improvement would mean that the forecast tool picked the right tercile 36.6% of the time.  A 20% improvement represents picking the right tercile almost 40% of the time.

     Results are shown in charts below.  Note that the testing is done on NOAA forecasts and outlooks for the Northeastern United States, not the Arctic.  Also note that the scales on the two charts are different. 

     The first chart shows that at the 1-month range, forecast skill is down to around 10% improvement over climatology.  The skill decay shown on the chart is relative to the very high skill for the short-range forecasts.  So it is a glass half-full vs. half-empty situation.  Short-range temperature forecasting is really good, so it is not surprising that longer-range outlooks have less skill. 

     I was surprised that the 1-3 and 2-4 month temperature outlooks were better than the 1-month outlooks.  That may be a fluke, but it may be because they benefit from estimating temperature over a longer, and therefore less specific, time period. 

     If we consider 10% improvement over climatology as a threshold for useful improvement, then the first chart shows that temperature outlooks, with skill improvement of ca. 15-20% out to at least 2-to-4 months, have some long-range skill for the northeastern U.S.  Conversely, precipitation forecasts run out of skill between 14 days and 1-month.  That lines up with some studies I've seen that found long-range precip forecasting losing skill at about 3 weeks.  But that's just me waving my arms about stuff I don't keep up with or in detail, so buyer beware.

     The second chart (using a more compressed vertical axis scale) shows that within the multi-month outlooks, the temperature outlooks stayed above 10% improvement out to the 4-to-6 month range, whereas precipitation skill bumps around the floor of statistical noise at every range from 1-to-3 months and beyond, thus again indicating a lack of long-range precipitation forecast skill (but they at least avoided negative scores which were possible).

     That uptick at 7-9 months for temperature forecasts is intriguing.  It could just be statistical noise.  But it could also reflect ENSO (El Nino/La Nina) forecasts actually having some slight (remember, we are talking about a mere 10% improvement over random guessing) skill at nudging the prediction in the right direction.

     A few years ago at a climate modeling workshop in Florida I met lots of folks from the southeast U.S. and got a different view of things vs. my home turf where there seems to be little attention given to local impact of ENSO forecasts.  But those southeastern U.S. folks absolutely worship the ENSO forecasts.  With good reason, as there is much higher correlation for their region with regard to the ENSO effects on temperature, and especially precipitation, in the following months.  That highlights the fact that my informal (not subjected to statistical significance) testing for the northeastern U.S. does not necessarily apply to even other U.S. regions, much less the entire planet.

11
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 17, 2020, 03:42:35 PM »
More Tamino goodness (referring to annual average ASI Extent):
"....annual average sea ice extent is not only still well below what it was 30 years ago, it’s well below what it would have been had the downward trend at that time continued unabated:" 
Bolding added.  See graph below.  And remember that adding 2016-2020 to the data in the Tamino graph keeps the linear trend heading downward.

    As for the Extent line requiring >40 years to go below 1M km2, look at the Volume graph.  It reaches 0 in mid 2032.  No Volume means no Extent.  (Digression - for some reason I'm reminded of Firesign Theatre's Porgy and Mudhead going to MoreScience High School the day before graduation, only to find that the Communists have stolen it!).

    As for which curve rules, remember that as average Thickness gets below 1M the ice is less resistant to melt.  Volume dictates Extent, not the other way around

    Tamino slammed the door shut on any notion of slowdown.  Arguing about the details really misses the point I think we all agree upon - the Arctic Sea Ice is getting destroyed.  The first BOE is just a day that will come and go.  The more pertinent questions are -

1) What can we do to slow the process? (I'll defer any mention of reversal until we do the first step of slowing the acceleration). 
     Of course, we already know.  Slow, then stop, then reverse greenhouse gas emissions.  The one good thing about loss of ASI is that it provides easily relatable visual demonstration of the progression and effects of climate change.

2)  What does diminishing ASI mean for weather patterns and other ecosystem changes that will affect all of us far beyond the Arctic?     

12
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 17, 2020, 03:29:46 AM »
NSIDC Extent minima, including 2016-2020 that Tamino did not have available for his analysis through 2015, showing that adding 2016-2020 continues the long term linear downward trend.

13
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 17, 2020, 02:44:17 AM »
RE":  <snip> The trend in the sea ice decline has slowed considerably over the past 15 years, compared to the previous 15.  Every year, the possibility of a BOE increases.  However, the recent trend shows that it is highly unlikely prior to 2030.
       Tamino/Grant Foster is/was the king of change point analysis.

And he did an analysis in 2015, based on extent anomaly data. For sea ice minimum, he found one change point, in 1996 if I read the graph correctly.

 https://tamino.wordpress.com/2015/10/01/arctic-sea-ice-2/

      I do not see the slowdown in the two Volume graphs shown below.  It looks like a consistent ongoing trend to me.  All the data points since 2005 are well within the expected variability of the downward linear trend.  The Volume minima for all of the last 6 years, and 7 out of the last 8, are within one standard deviation (=close) to the trend line.

      As for annual average Extent, the great Tamino did not find a slowdown when looking at data through 2015.  He did find a temporary slowing for 2002-2006, then for 2006-2015 it was back to the original downward rate of decline.  See whisker graphs in the 3rd graph below. 

      When Tamino looked at annual Extent minima, he found a statistically significant increase in the rate of decline in 1996 (see the downward kink in the blue line of the 4th graph below).  He did comment that a smoothing of the data hinted at a possible plateauing in the final few years of those data, but there was too much variability to conclude anything about a rate change based on so few points in such variable data.  The Extent minima in the subsequent years (2016-2020) proved that his caution about concluding anything about the long term trend from those few years was justified.  When 2016-2020 are added, the trend resumes its linear downward slide, thus refuting that hint of a rate plateau (to my eyes, not statistically tested, but I'd bet my lunch money on how that test would come out).  See the NSIDC graph in the next post.  I wish we still had Tamino or someone with his skill set putting such questions through the statistical blender.

      While it is possible that "negative" suppressive feedbacks to slow further losses will strengthen and dominate as Volume gets closer to zero, it seems more likely that the reverse is more likely, i.e. that "positive" reinforcing feedbacks are more likely to strengthen and dominate to accelerate losses. 

      Most ASIF folks already know the list of potential reinforcing feedbacks, so I won't repeat them.  The weakening of halocline stratification is a more recently recognized (to me at least) addition to that list.  Based on studies by Polyakov et al., Timmermans et al., and others, the surface - subsurface water characteristics and relations seem to be of increasing importance for at least some locations in the Arctic Ocean, though I have not read those studies closely or recently enough to comment on the scale of their potential impact relative to entire regional seas or to the Arctic Ocean overall. 

      My question about unexpected drift pattern may be unjustified alarmist arm-waving, but with people in the Forum more familiar with the historical record it seems worth asking to either confirm my suspicion or dismiss it.  (The only "dumb" question is the one left unspoken.) 

      Even if the November 2020 drift graph posted by A-Team is just a meaningless blip, that still leaves the weightier statement about decline of halocline stratification in the Polyakov et al. abstract (and by my inference, the consequent decline in isolation of ASI from interaction with subsurface water).  Seeing an expert like Polyakov use the term "tipping point" about any aspect of the ASI is enough to give me the willies. 

      I do admit that my ears are tuned to hear that dog whistle, because I fully expect that by pushing the climate system, and the Arctic in particular, beyond its previous "performance envelope", then something is going to snap in a non-linear, non-incremental, and very abrupt and "surprising" (but we knew it was coming in one form or another) way.

14
Arctic sea ice / Re: Latest PIOMAS update (November)
« on: November 12, 2020, 06:40:41 AM »
       Tamino/Grant Foster is/was the king of change point analysis.  Grant, if you're listening we need you back!  Until he or someone else shows up, I can only relate that from many Tamino blog posts that used change point, one theme was that what looks like a valid change point is not when subjected to statistical testing.  Non-random significance (like beauty) is often in the eye of the beholder.  I'm not saying this to rain on the "2007 fundamental change" question, I am just noting that until we have a statistical test the eyeball view alone cannot be trusted.

       FWIW, my own opinion about 2007 is to agree with you from a different basis.  It seems to me that the loss of multi-year ice in 2007 either reflected or helped initiate systemic changes in the ASI system.  Various posts in the forum have described how, even though 2012 gets most of the attention since it holds the records, that when looked at from different points of view, 2007 was the Big Year.  I have no hope of remembering in which thread, but (I think it was) Oren or BFTV who put up a post this summer listing losses from September to September which showed that when viewed from that time frame, 2007 outdistanced every other year for losses.  So that's a second (but also not statistically validated) observation to lend weight to your proposition. 

       2012 had strong summer melt season weather topped off by perfectly timed and positioned cyclone to break up ice and pull subsurface heat to cause new low September minima.  I don't have 2007 summer melt weather in my head, but I don't think it was as forceful as 2012, and certainly did not have a storm like the GAC 2012 to push it over the edge.  Which leaves it up to other underlying changes that caused (at the time) new record lows. 

       My foggy recollection is that one contributing factor in 2007 was just enough extra floe mobility combined with conditions conducive for Farm or CAA export to send a lot of multi-year ice out of the central Arctic Ocean to its southern doom.  I also think that the Beaufort Gyre faltered as the nursery for multi-year ice in 2007.  Perhaps folks with a better handle on these fuzzy factoids can bolster or refute them, or add other lines of evidence about whether 2007 brought unique forces or outcomes to the ASI saga.  After the unprecedented losses in 2007, there were journal article autopsies about what caused the losses observed that year.  I don't have any specific links to share, but they exist.   

       As for photobucket.  It sounds like you have Excel.  You can make charts in Excel, save them as screen clips to Excel or Word, then click on the image and "Save as Image" to make a file copy on your hard drive.  With that done, then when you write an ASIF post, use the Attachment link below the text box on the Reply screen to upload those saved chart images. 

       Sorry if that it is so blindingly obvious that you are wondering why I would bother to mention it.  Here is why.  I was messing around with different image hosting services until somebody on ASIF reminded me about the Attachment link on the Reply post form.  I had not realized that was a way to upload images.  Yet another in a lifetime of dope-slap to forehead moments, i.e. making something difficult that did not have to be.  The Attachment link is how the ASIF forum platform provides its own image upload and hosting service.

15
Arctic sea ice / Re: The 2020/2021 freezing season
« on: November 12, 2020, 02:58:46 AM »
       +2.7C per decade is Monstrous.  It is more than 10X the rate of increase in NASA GISS (and other) measures of global average surface temperature.  At risk of being one of those alarmists, +2.7 per decade looks like a possible break out from system equilibrium into scary out-of-control realignment to an entirely new climate regime.  Maybe the fact that it is an October-only single-region value, and not the whole year/whole planet is some cause for not seeing this as an unfolding catastrophe.  If it was a whole year planet-wide rate, we would be into Mad Max territory.  Somebody who actually studies this stuff can correct me if I'm wrong, but +2.7C per decade (he says for the 3rd time in one paragraph) is absolutely nuts and unsustainable within the Holocene climate envelope upon which Human civilization is built and dependent.  At that rate, the Laptev bite is going to be the CAB bite sooner than any of us ever foresaw.

       Some people play fantasy football, I play nightmare planet by tracking NASA GISS and daily Climate Forecast System reports.  Entering 2020, my magic predictive formula (which has been more accurate than UK Met and NASA GISS's Gavin Schmidt's prognostications over the last few years) called for 2020 to be several points (0.01 C units) below 2019, due to a weak ENSO signal and coming off of the bottom of the solar cycle.  But as 2020 winds down, the current end-of-year-average projection has a 95.8% chance of beating 2019, and a 68% chance of topping 2016, the previous record-holder for warmest yearly global average surface temperature.  Keep in mind that 2016 had a strong ENSO and a solar maximum pushing it up.  The graph below shows the annual average GISS with ENSO/Solar/Aerosol forcings removed to see the underlying temperature without variation due to single-year forcings.  (Too bad Tamino is not posting these days, it would be great to read his take on this).

       The last time I sort-of looked, it was hard to see a correlation between annual GISS and ASI Extent/Area/Volume values.  Of course, warming the planet as a whole eventually shows up in the Arctic.  With La Nina kicking in for the next few months, that should put the brakes on GISS increase over the next six months at least, but I have no clue if that would show up in the Arctic or in the ASI stats.  Remember that a cool La Nina year does not mean the Earth system is cooling, just that more heat is going into the ocean vs. the surface atmosphere than in an ENSO-neutral or El Nino year.  Heat in the ocean has a bad habit of melting ice.

       Looking ahead to 2021, based on the ENSO/Solar/Aerosol predictors, the GISS surface air temperature should be slightly cooler than 2020.  But that is from the formula (that explained >80% of year-to-year variability... until 2020) that said 2020 should be cooler than 2019.  The fact that my previously reliable formula failed in 2020 feeds my wonderings if Earth's thermostat is broken, and that the climate system is playing by new rules.

       As for right now, the DMI 80N temperature is starting to look like the winter of 2016-2017 when there was a low accumulation of freezing degree days.  Going out on the limb of my ignorance, I'll hazard a guess that for the near term at least, the recent above-average increases in Extent and Area could lose some momentum.  If that DMI anomaly does not fall, it is easy to imagine a new record low maximum in spring 2021.

16
Arctic sea ice / Re: The 2020/2021 freezing season
« on: November 08, 2020, 08:06:46 PM »
    And now we can add warm Siberian river drainage into the Arctic Ocean as another factor (article posted upthread).  Given the record breaking high Siberian temperatures over land in summer 2020, the river water draining those areas must have been especially warm.

17
Arctic sea ice / Re: Freeform season chatter and light commentary
« on: November 07, 2020, 10:19:26 PM »
Thanks kaixo, interesting perspective. Jim Pettit has graphic along similar idea, as does gerontocrat (but I can't find his version)

18
Arctic sea ice / Re: MOSAiC news
« on: November 05, 2020, 02:16:17 AM »
<snip>How much will the long-delayed freeze-up affect ice growth during the winter (and ice quality going into melt season)? We have no idea how cold the air will be between now and then. However we do have reanalysis products up through early November plus daily ice thinness from Smos-Smap and even rate of growth from Cryo2Smos.

It's also feasible to make a map showing how many days each point in the Arctic Ocean has had an ice cover and what the 'deficiency' has been this season given the Laptev, ESS and Chukchi open water anomaly.   <snip>----etc.
    Great info A-Team.   It would be great to have an average age metric to add to an Arctic Sea Ice Multi Metric Index.  It seems like that info is embedded in the data used to create the ice age map.  Specifically, do those data allow conversion into a daily "average ice days" value across a grid cell map of the Arctic Ocean, or the central Arctic seas? Or at least the CAB?

    Do you think that average ice days would carry within it some proxy/correlated information about salinity or other characteristics that affect melt resistance?  Thickness already does that to some degree, but I think it does so incompletely.   That is because I suspect that not all ice of the same Thickness has equal physical characteristics or melt resistance.  My guess is that 2-meter ice that has been around for a while and thus had more time to expel salt content or get compressed by pack motion is different than younger 2-meter thick ice. 

     Just a bunch a notions and questions from an amateur ASI watcher who does not know the details but looking for patterns.  Thanks for your contributions to our understanding this very complex system.   

19
 
current Siberian anomaly for example ? ..  https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=290316;image
   You got me on that one!  I was focused on global year-round land vs ocean warming.  I look at the Arctic Ocean temp. anomaly on CR regularly, so you'd think the ocean vs land difference would have sunk in.  Useful to be reminded of my ability to misperceive or misplace evidence. 8)

20
     That temperature map is not convincing.  A temperature map of the Arctic Ocean and surrounding landmass is needed, not a side view with the Arctic gets crushed into a thin slice at the top.  From what I recall Siberian land temperatures have frequently been 10C or more above historical norms in 2020 vs. Siberian sea temperature anomalies much lower than that.  So based on that larger net difference, I would say Siberian land mass is warming faster than Siberian seas. 

     Again, the whole field is out of my league, so I have no opinion about how relative land vs sea temperatures might affect air pressure distribution, variability, timing, or resulting weather.  I'm just questioning the assertion that Siberian seas are warming faster than land.  On a global basis that is not the case, so it would be odd for the Arctic to follow a different pattern.  But I just re-read your original message, and your hypothesis does not require seas to be warming more than land, just that cold air coming off of land now overlays seas that were warmer than they used to be.  Which is certainly the case for open water vs. ice covered sea.  So I'm outta here!

21
     El Cid - you asked for comments, so here goes from someone who knows little about the air mass dynamics.  Even with the Siberian seas warming, it seems that the net difference and thus interaction between the Siberian seas and the very cold Siberian land mass in winter may not change that much, or may change in the other direction. 

       With a more insulating CO2-enhanced atmosphere, the winter land mass must also be warming by as much or more than the Siberian seas are warming.  Globally, land masses are warming faster than the oceans.  So presumably that is also true around the Arctic Ocean.  If so, how does that affect your hypothesis?

22
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 31, 2020, 04:46:29 PM »
<snip> The fall season is peak Arctic Amplification,
     My understanding is that Arctic amplification is primarily due to less ice Extent --> albedo decline --> more sunlight energy absorption by dark open water --> warmer water --> more ice melt --> less ice Extent.  With very little sunlight reaching the Arctic at this time of year, how is it that fall is "peak Arctic amplification"? 
 
     I suppose more open water also creates more moisture in the air and thus a thicker insulating blanket to retain heat emitted by the open water, thus another reinforcing feedback.  But albedo change seems to be the most important forcing change caused by Arctic warming, and that change in net forcing should decline to near nothing in the fall.  So I don't understand how fall could be peak amplification unless "amplification" is a noun that refers to the observable impacts, not as a verb that describes additional forcing contributions.

     Thanks to Oren for "moderating."  I'm one of the 1783 ASIF members with no training in Arctic science or climatology.  I come here to learn and see what's happening in what is arguably the most consequential observable event in human history - the degradation of the Arctic sea ice.  I do work with weather and crop pests, and one of these days I suppose I could learn how to work with netCDF files, but it will never happen.  I have a colleague who does that.  But he doesn't know much about managing insects and diseases that attack crops.  So we each do our part.  We can't each do everything.  It's better if I let him handle the netCDF programming so I can focus on keeping up with the biological developments from my reading of the relevant information from about 1% up to maybe 2%. 

     The world is a complicated place.  It's great that we have access to so much information.  But it is also overwhelming, so we have to pick our spots.  Adding buoy analysis is not the right move for me or for bettering the world.  Scolding me about it is not going to change that. 

     I wish we had 1.7 billion people in the ASIF watching and worrying about the Arctic, whether or not they ever post any data analysis.  ASIF plays an important role in raising awareness, which is a necessary prerequisite for solutions.  I know at least one prominent journalist aware of the ASIF, and I'm sure there are many others.  I hope ASIF remains an open conversation that welcomes all and brings attention to the climate crisis. 
     
     And it IS a crisis even though for political purposes it seems to move too slow to meet that definition.  The faster that train rolls the less we can do about it.  It's already moving, and 30 more years of acceleration is already baked into the cake. It's like Dr. Fauci said about COVID-19, if you think you are here (low on the curve), you are really here (farther along and higher on the curve).  So you have to act accordingly.  Our house is on fire.  We need to support each other in whatever capacity we each have to attack the problem, not each other.

23
Warmer climate and Arctic sea ice in a veritable suicide pact https://yaleclimateconnections.org/2020/10/warmer-climate-and-arctic-sea-ice-in-a-veritable-suicide-pact/

----------------------------------
      Excerpt:  “Ever since the record-smashing summer of 2012, Arctic scientists have watched melt seasons unfold with bated breath: Will this year break the record again? Will this year bring the long-anticipated sea-ice-free summer?” said climate scientist Jennifer Francis of the Woodwell Climate Research Center. “And almost every August, the rate of ice loss came to a screeching halt, averting a new record minimum. But why?”

"What froze the death spiral?
      Francis and her co-author Bingyi Wu of Fudan University in Shanghai have a theory that the rapid warming in the Arctic prompted a change in the polar jet stream, the narrow band of strong wind circling the region; they theorize that this change helped preserve some sea ice. Their new study in Environmental Research Letters notes that the winter and spring sea ice extent reached record low levels nearly every year since 2012 … but then the trajectory took a sharp turn late into the summer season, with the loss curbing early and therefore avoiding setting a new record low annual minimum in September.

      Francis and Wu identified a common pattern in atmospheric air circulations during many of the summers since 2012: Low-pressure systems would develop in the Arctic, forming clouds that kept temperatures cool by blocking sunlight and generating winds that spread out the remaining ice."

      The study discussed is available via open access at https://iopscience.iop.org/article/10.1088/1748-9326/abc047/pdf
----------------------------------
 
      Good article, but I don't think ASIF vets have been very surprised that the devastating 2012 freak-cyclone bottom-fell-out crash has not been repeated in the few years since.  Maybe Francis should call sark for additional insight on those jet stream patterns.

      What is more notable than the 2012 records lasting this long is that due to continuation of the long-term trends, both 2019 and 2020 approached the same melt levels as 2012 without input from freak events.  The GAC 2012 certainly made its mark, but because it used up some stored heat in doing so, the subsequent years saw a regression back to the trend line.  But now even the "new normal" levels are near (and going below in 2021?) what used to be freakishly low record-breaking levels less than a decade before.  Welcome to the future.  It didn't take very long to get here. 

       So that I can tell myself I'm not just kvetching, here is my attempt at an inspiring conclusion: - Do not go quietly into this dark night, talk about it, and please make sure that you, and folks in your social networks, vote climate wherever you live at every opportunity.  This insanity won't end until we make it end.  The infrastructure and other changes required to remake society (Make Earth Great Again?  :-\) is not only essential, it is the perfect opportunity to address many other interconnected social, economic and environmental problems.  To the guy who recently said "We can do this", I'll add "We HAVE to do this."

24
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 28, 2020, 08:42:24 PM »
Average remaining extent gain (of the last 10 years) would produce a maximum in March 2021 of 12.49 million km2, 1.39 million km2 below the March 2017 record low maximum of 13.88 million km2.

For the 2020-21 maximum NOT to be a record low, remaining extent gain has to be more than 21.0% above the average remaining extent gain of the last 10 years. This is greater than any of at least the last 13 years.
     10-year average gain may not be that useful under this anomalous circumstance.  Those earlier years had already "used up" a lot of open water freezing capacity by this date.  So when 2020-2021 does begin freezing it will have more opportunity for rapid increase.

     But also note that even at the highest remaining gain for the past 13 years (7.61M km2 in 2019-2020), the resulting maximum at 13.49 would still be 0.39M km2 less than the previous record low maximum Extent of 13.88.   To NOT set a new record low Maximum, remaining refreeze must exceed the highest refreeze within the last 13 years by over 5%.

     Even with rapid catch up once freezing begins late, the longer this delay persists, the more difficult it is for refreeze to compensate for so much lost time.  (Duh, another stunningly obvious revelation, but at least I put numbers to it. :D)

      As noted by more learned souls, even if/when Extent more or less catches up to "normal", the thickness and quality of that ice won't be the same.  I hate to use a boxing analogy, (a sport I can no longer watch given what we now know about brain damage), but the ASI is like a boxer who has taken too many punches to the head.  It will get off its corner stool for the next round of melt season in April, but it will be less able to resist further blows if there is another warm or sunny Arctic summer like 2020.  It looks like the 2012 record lows won't last much longer.  Not good. 

     Winter is supposed to be "off-season" for ASIF, when we twiddled our thumbs and waited for the next melt season.  Freeze season is not supposed to be this "interesting."  Now the refreeze race to a depleted maximum is almost as interesting as the annual September minimum derby.

25
Arctic sea ice / Re: What's new in the Arctic ?
« on: October 27, 2020, 11:43:42 PM »
    Huh?  They say
 "....the Arctic could become ice-free in summer for the first time within the 21st century. Projections with CMIP-5 (Coupled Model Intercomparison Project Phase 5) models show that this could be the case as early as 2030 to 2050 for higher emission scenarios such as RCP8.5 (Representative Concentration Pathway). Some GCMs (global circulation models) show an ice-free Arctic for the first time within this century also for the moderate emission scenarios at a warming of 1.7 °C above pre-industrial. Furthermore, observations reveal that the Arctic summer sea ice declines faster than expected in experiments from GCMs."

     Which is accurate when the term "ice-free in summer" refers to < 1M km2 ASI Extent at September summer minimum.

     Then they are vague about what ASI Extent or Area they plugged into their model.  But in Figure 1a the caption says "Regional warming for the whole Earth if Arctic summer sea ice (ASSI) in June, July and August, mountain glaciers (MG), Greenland Ice Sheet (GIS) and West Antarctic Ice Sheet (WAIS) vanish at a global mean temperature of 1.5 °C above pre-industrial.   (bolding added by me).

     ALL ASI vanishing in June July and August (as in zero Extent-Area-Thickness-Volume) during peak solar input is an entirely different scenario than reaching ASI > 1M km2 Extent for a couple of days in September before refreeze resumes.

     So which is it?  <1M km2 ASI Extent or Area at September minimum, or ASI vanishing to give zero km2 ASI for June 1 - August 31?   Based on the Fig. 1A caption, it seems to be the latter, which renders that first paragraph completely out of context with their simulation and egregiously misleading.   

      Before noticing the aforementioned oddity, my hackles got raised by Figure 4.  It is one of the most easily misinterpreted, and therefore poorly designed, data graphics I have ever seen.  The X axis on a chart implies that X values cause the Y axis values as a response.  But that is not really what is happening in Fig. 4.  A reader could all too easily look at that chart and think it says that at 2.5C above preindustrial global mean temperature (GMT) we should expect 4M km2 summer ASI Area.

    At https://forum.arctic-sea-ice.net/index.php/topic,2975.msg286961.html#msg286961 our friend gerontocrat made it back safely from his foray into the COVID-19 infested streets to buy booze to let us know that on September 18 ASI Area reached 2,631,888 KM2. 

     2020 is coming in hotter than expected, with a good chance of beating out 2016 as the warmest year in the modern record (disturbing that given solar minimum AND piddling ENSO signal, 2020 should have come in well below 2016 despite 4 more years of incremental warming since 2016, but that's for another rant.)  2020 is nowhere near +2.5C > preindustrial GMT, yet September minimum ASI Area is already well below 4M km2 (and has been for a while). 

     Fig 4. exacerbates the confusion by showing a labeled 1979-2006 average ASI summer minimum sea ice area range of ca. 5.75M - 6.25M km2.

     I think what Fig. 4 is trying to say is that IF ASI vanished in context of GMT at +2.5C, we should expect about 0.10 C additional warming due to the increased Arctic albedo (shown on the right axis).  Whereas, if ASI vanishes for June - July - August  when GMT is at +1.5C, then we should expect an additional 0.18 C of albedo induced warming from that cause.

     So what the heck is the left Y axis referring to?  I tried to help them out by guessing, "Oh, they mean average ASI Area for June-July-August at those GMT values.  Thus about 6.8M km2 average ASI Area for June-July-August at 1.0C.  Conveniently, glennbuck had posted just the chart I needed just below the gero post at https://forum.arctic-sea-ice.net/index.php/topic,2975.msg286915.html#msg286915.  Yes, that fits.

     But then why does the label in Fig 1A say "Minimum Arctic sea ice area (observations) average 1979-2006"?  Those values are the June-August average, not the average of the summer minima.  And what does it add to this chart except confusion?

     Correct me if I'm wrong.  Maybe I'm too dumb or tired to understand what they are saying.  But I think it is the other way around.  It is the authors' responsibility to communicate clearly, a task at which this article fails, and worse than that it very easily leads to gross misrepresentation to, and misunderstanding by, the reader.

     The ASI situation is truly bad and getting worse.  But the entire 3 month period of June-July-August is not going to be ice-free in the 2030-2050 time frame. 

      Conversely, summer minimum ASI Area is already well below 4M km2 at our present +1.1C, so there is no way that September minimum ASI Area at +2.5C GMT will be near 4M km2.  There won't be ANY September ASI Area at 2.5C GMT over preindustrial. 

     At least the fallacies balance each other.  But leading the reader to counteracting fallacies is not good enough, in fact it's a mess.




26
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 22, 2020, 11:50:23 PM »
     I'll pass those comments along.  Out of my league to make any comment.

27
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 22, 2020, 10:27:48 PM »
Climate reanalyzer does not foresee 2m temperatures dropping too much over the next ten days. Because some colors are dithered (for print!?!), the correspondence with the color bar is poor. Accurate tick marks cannot be put on the color bar because its pixel width is not an integral multiple of degrees. These errors degrade expensively acquired data so need to be fixed.
     The brain and 10 nimble fingers that singlehandedly (correction: 10 fingers = 2 hands) operates Climate Reanalyzer is aware of your critique.  The reason for dithering the color scales is because for the weather forecast animations it reduces file download size by a factor of 6X.  The file sizes are not so large as to matter for folks on an unlimited-data high-speed connection, but for people on a slower (or data-metered) connection (DSL was mentioned as a slower connection, and smartphone internet is an example of a metered connection), the file size does matter. 

    That person also mentioned that for stand-alone images, dithering the color scale may not be necessary so a possible change will be investigated.  Suggestions are well received, just remember that while CR may look like some well-funded institutionalized juggernaut, it really is a part-time operation by one person with a vision, programming skill, and committment who built something nobody else (including well-funded institutionalized juggernauts) had gotten around to doing, and done while juggling multiple other responsibilities and deadlines, including a recurring requirement for periods away from the keyboard to eat, sleep and other aspects of life.

28
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 22, 2020, 05:24:34 PM »
Once the water is back to to freezing, the ice will form at the same sort of rates, but it'll be a few days later than in the past...
I'd say it will be a faster refreeze as the surrounding air and the continents will be much colder by then than during previous refreezes. Late but fast refreeze. We shall see
      The Guardian article mentions a possible ecological impact on nutrient transfer from the delayed Laptev Sea refreeze.  It seems likely that once refreeze begins it will be more rapid than "normal" because it will be occurring at a later date.  That makes me wonder if the rate of Arctic Ocean refreeze has important but little-discussed impacts.  If the ice pack edge advances many more miles per day than normal, how does that affect the microscopic and macroscopic organism communities that interact with the water/ice environment?

       Ice vs. water is a major habitat change, and the rate at which that habitat shift occurs could have consequences.  While I doubt that ice-edge advance is going to be so fast as to outrun the ability of air-breathing marine mammals that need access to open water to relocate, that's an extreme (though I think implausible) example of the kind of scenario that comes to mind.  What seems more likely is some effect on the colonization, population growth rate, and niche partitioning of microflora/fauna on newly formed ice.  For example, it may make a difference to community structure if there only 3 versus 30 days between initial colonization and the date when discriminating environmental conditions occur. 

       The relative timing of such events may have trivial consequences, or it may not.  Small differences over such a large scale can have a large impact, especially in a tightly linked system where each domino affects all the following dominoes.  Even though Extent / Area / Thickness / Volume will probably return to closer to the normal range quickly once refreezing begins, even getting back to a closer match with "normal" values after a late refreeze start and rapid rebound may bring with it subtle but significant qualitative physical, chemical, biological and/or behavioral differences that are not apparent from the quantitative Ex / Ar / Th / Vol measurements. 

       The fact that the Russians could not really test their new ice breaker on a run to the North Pole because the ice was too thin and broken is not an Earth-shaking consequence, but it exemplifies how changes ripple through a system in unforeseen ways.  Everything is connected.  I do not expect obvious or catastrophic impacts, but the potential effects of refreeze timing and rate do seem worth noting.  I wonder if/how Arctic scientists are tracking such potential qualitative impacts.

29
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 09, 2020, 11:32:32 PM »
     Of course adding heat is not going to make the Arctic get colder.  That is not what I said and is not implied by the term negative feedback.  My point was that an energy increase that results in more open water that results in increased LWR that results in increased energy lost from the system will have a negative feedback effect to partially counteract that initial energy addition.  That influence would act to partially revert back to the initial energy state but not go below it. 

     Unless a negative feedback is 100% effective (unlikely if not impossible without some other state change), it will not cause a system to even get all the way back to the initial state.  Adding energy to a system increases the energy in that system.  But a negative feedback acts to make the net gain in energy somewhat less than the initial value plus the added amount.  As the negative feedback acts to bring the system back towards and closer to the intial energy state,  the weaker that negative feedback becomes, so the system can't end up being less energetic than it was initially.  (And now somebody can point out some chemical system etc. where negative feedbacks can indeed overun and go below the initial state, but I can't see how that could possibly apply in a large complex system like the Arctic Ocean.)

     My point was that I think binntho was overreacting to his epiphany from A-Team.  Increased LWR can have some effects on air temperature or water vapor on its way toward space, but some portion of that additional long wave radiation will go into space, thus leaving the Arctic system.  That loss will cause energy loss from the system and, to some degree, that loss will function as a negative feedback on system energy level, i.e. warming.  Sorry if I am being pedantic, but your response so completely missed my point that I feel the need to be as explicit as possible.

30
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 09, 2020, 08:37:18 PM »
<snip> Open water during the polar night *is* the positive feedback, the ultimate cause of Arctic amplification.
   But surely increased Long wave radiation outward from the ocean does result in increase of energy exported out of the system into space.  Not all of it is captured in the atmosphere to contribute to Arctic amplification.  Therefore, to some extent open water ---> increased LWR ---> is to some degree a negative feedback that works to stabilize Arctic energy balance.

    Granted all that LWR does not immediately leave the system, and can cause intermediate effects such as warming the overlying blanket of air and water vapor along the way.  Thus, there are feedbacks within the larger open water --- LWR feedback.  But the net effect of greater LWR emission has to result in more energy leaving the system eventually, and thus to some degree serve as a negative feedback.

31
....but, the plot thickens even if the ice won't.

     There is more to the situation than thickness alone.  Structural integrity, decreasing albedo etc. seem very likely to provide reinforcing feedbacks as ASI declines.  Here's a list of potential positive and negative feedbacks not accounted for in a simple regression trend extrapolation.

Acceleration factors NOT accounted for:
     Higher salinity and lower melt resistance of thinner and thus generally younger ice.
     Increased open water leads to longer wind fetch and increased wave height.
     Reduction of mechanical strength and structural integrity of thinner ice leads to fracturing of contiguous ice into smaller pieces.
     Ice fractured into small floes is more vulnerable to wind and current transport into melting zones of the lower latitude CAA and Beaufort Seas following the typical ice movement, and by export via the Fram Strait into Greenland Sea, and also into the lower latitude peripheral ESS, Laptev, Kara and Barents Seas.  As those seas progressively melt out earlier in the summer, that reduces their physical blockage against ice exports out of the CAB.
     Increased proportion of Arctic Ocean as open water results in albedo decrease and increased solar energy absorption during summer, warming surface water.
     Combination of increased wind and open water increases water column turbulence, increases Ekman pumping, weakens halocline thermal isolation, and warms surface water.
     Fractured ice has higher proportional exposure of lateral surface area to ocean water melting energy.
     Greater portion of open water in fall and winter increases atmospheric humidity and cloud cover,  thus increasing reflection of long wave energy emitted from open water back down resulting in (relatively) warmer Arctic night.
     Warmer Arctic Ocean water in summer is likely to generate more cyclone activity leading to more wind damage and Ekman pumping.
     Warmer Arctic air temperatures decrease gradient with lower latitude air, reduces jet stream strength, and thus reduces Arctic isolation from warm southerly air masses.
     Earlier seasonal melt of snow cover on land surfaces surrounding Arctic Ocean increases terrestrial warming that then warms overlying air masses that carry some of that energy into the Arctic Ocean.
     Warmer Arctic air holds more moisture potentially resulting in more rainfall onto sea ice thus increases energy transfer from atmosphere to ice.  The latent energy per gram in liquid rain is large relative to the energy required to melt a gram of ice.
     Progressively stronger Atlantification and Pacification of Arctic Ocean waters are huge influences promoting loss of Arctic seas ice.

Deceleration factors not accounted for:
     The remaining ice more likely to be located in protected bays and other locations less exposed to melting energy.
     With loss of multiyear ice, Volume losses due to Farm export has declined and may continue to decline.
     Rapid freeze and thickening of thin ice allows rate of winter ice formation to quickly recover from summer losses, thus restoring Extent and Area coverage to maintain albedo for following summer.
      Warming surface water and increased melt strengthens the gradient protecting surface fresh water lens from subsurface heat?
     Greater area of open water in fall and winter accelerates greater ocean water energy loss to atmosphere (but rapid thin ice recovery provides insulation to work against this).
     Greater area of open water in summer increases cloudiness to block incoming solar energy.
     Warmer Arctic air holds more moisture potentially resulting more snow deposition to increase albedo on ice and surrounding land masses.

32
Arctic sea ice / Re: Glossary ... for newbies and others
« on: October 03, 2020, 11:35:49 PM »
   I hear you.  I was just responding to gerontocrat's CAS graphs and trying to clarify "CAS" vs CAB.  But apparently there is no such CAS label, just different definitions for CAB.  So I change that suggestion to a new one -- the glossary should note that CAB has different definitions between NSIDC and others.

33
Arctic sea ice / Re: Freeform season chatter and light commentary
« on: October 03, 2020, 11:28:26 PM »
https://www.forbes.com/sites/jeffmcmahon/2018/01/15/carbon-pollution-has-shoved-the-climate-backward-at-least-12-million-years-harvard-scientist-says/#13f60898963e

"The chance that there will be any permanent ice left in the Arctic after 2022 is essentially zero," Anderson said, with 75 to 80 percent of permanent ice having melted already in the last 35 years.

"Can we lose 75-80 percent of permanent ice and recover? The answer is no."
    +1.  Nice catch glennbuck.  Note that the title of the January 2018 article is "We Have Five Years To Save Ourselves From Climate Change, Harvard Scientist Says"  2.75 down, 2.25 to go?

     Not really anything factually new, but a useful article for the collection because:
1)  Authoritative speaker (ozone, Harvard, award etc.)

2)  Impactful message (climate change is serious business, here are some reasons why (Harvard - your new $10 billion campus is in a future flood zone, bye bye south FL, etc.).

3)  Short and to the point.
             
           But what I really like about it (in a blatant case of confirmation bias) is the way that the article succinctly introduces the moral component and complicity of policy makers. 
          "I don't understand how these people sit down to dinner with their kids," Anderson said, "because they're not stupid people."  That's been my zen koan for over a decade.

          Exactly.  The struggle is not about the facts.  The deniers know the facts better than what they let on.  It is precisely because they DO understand the facts that makes them fearful about what those facts require in response.  It is that psychological and moral interface that we need to address to create the unified broad scale effort that is the only way to get through this adolescent transition for human civilization.  Unless we all pull together in the same direction, this boat isn't going to move.

          Those of us fighting for solutions need to focus less on the factual arguments and more on heartfelt listening to folks repeating distortions cynically supplied to them by people who know better but choose to ignore reality for some mistakenly perceived personal gain.  We need to get to both the heart of the issue and its brain (the scientific and technical stuff).

          Our use of fossil fuels has been like a guy in his late teens and early twenties letting it rip, and then realizing one day that his party hearty lifestyle isn't working for the long run, or even in the short run when he confronts his illusions, delusions, and fears and faces the facts.  I'll stop there, because this is the freezing season thread, not the climate change salvation pulpit.  But thanks for reminding me what really matters about watching the Arctic sea ice not so slowly die. 

34
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 02, 2020, 06:58:04 PM »
It makes me think all that ice is going to 'fall off' (break loose from Greenland/CAA/Alaska) and hit me on the head (as an icicle hanging from an eave might [or worse - refrozen half melted snow that partially slipped over the eave's edge before temporarily refreezing in place] ). 

With Greenland (or Canada) at the bottom, all that landmass will hold the ice up forever...
 :)
     To my eye that orientation highlights the fact that much of the remaining ice is at latitude below 80, so presumably more vulnerable to future melt.

35
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 29, 2020, 03:07:10 AM »
Ocean Stratification is Not Good News. Very Not Good.
https://climatecrocks.com/2020/09/28/ocean-stratification-is-not-good-news-very-not-good/

"This seemingly technical finding has profound and troubling implications. The more stable the upper ocean, the less vertical mixing that takes place. This mixing is a primary means by which the ocean buries warming surface waters. So the surface warms up even faster. It’s what we call a “positive feedback”—a vicious cycle."

"Our study suggests that key positive feedbacks (amplifying factors) related to reduced ocean heat might lead to more rapid surface warming in the decades ahead than many of the models predict."

36
Arctic sea ice / Re: What's new in the Arctic ?
« on: September 25, 2020, 09:58:54 PM »
Journal article - The hysteresis of the Antarctic Ice Sheet
Julius Garbe, Torsten Albrecht, Anders Levermann, Jonathan F. Donges & Ricarda Winkelmann
Nature volume 585, pages538–544(2020)
https://www.nature.com/articles/s41586-020-2727-5
    New (to me) term - "Creep instability"   Good fit for the times.

"The Graduate" updated for 2020:
Mr. McGuire:  I want to say one two words to you. Just one two words.

Benjamin:  Yes, sir.

Mr. McGuire:  Are you listening?

Benjamin:  Yes, I am.

Mr. McGuire: Plastics.  Creep Instability.

37
Arctic sea ice / Re: The 2020 melting season
« on: September 24, 2020, 10:07:35 PM »
<snippage>
But we must not forget the third vector of energy infusion - ocean heat. And I would suggest that it is dwarves the others - but is at the same time inefficient in a melting contexts, since most of the heat does not reach the ice.

So can we rank these vectors and their interplay when it comes to melting ice? Even if Insolation would seem to be the favorite, we must remember that it still accounts for only around half the melt (simply because so much of a melting season happens outside of peak insolation).

Most of the rest I suppose is caused by ocean heat. And this is where storms kick in - they act both to give mechanical force to the system, mixing waters and moving the ice, and thus enabling the ocean heat to interact more efficiently with the ice. And secondly, the increased air temperatures and moisture that a storm carries in over the ice has it's origins in that same ocean heat.

So I'd suggest that insolation and ocean heat are the two main drivers of melt each year, with storms playing an important part in bringing the latter to bear on the ice, thus increasing melt at all times other than the during peak insolation.
   The Atlantification paper posted about a week ago stated that in the Laptev Sea study area ocean heat diffusion from incoming warm Atlantic water (now exacerbated by thinning of the cold halocline and increased turbulence), was equal to atmospheric warming as a cause for ice melt.  The ASI is getting hit from all sides.

   Edit -- Found the article:  https://journals.ametsoc.org/jcli/article/33/18/8107/353233/Weakening-of-Cold-Halocline-Layer-Exposes-Sea-Ice

38
Arctic sea ice / Re: What's new in the Arctic ?
« on: September 24, 2020, 09:35:59 PM »
So if we manage to get CO2e past 750 ppm Antarctica melts to the bedrock and the seas rise 70 meters or more?
     70 meters will take a long while, but if 3.3 meters floats your boat that can happen at just  650ppm held steady long enough according to a study published yesterday.
 
      Study out yesterday found that eventually West Antarctic Ice Sheet is drinkable at 2.36C above preindustrial.  IPPC 2014 CO2 and Temp tables for RCP8.5 (closest analog to path we are currently on) put 2.36C at about 650 ppm CO2.  Quick skim of article did not find any timeline should that occur, and they take pain to say their report is NOT a projection or forecast.  Based on Deconto and Pollard 2016 simulation, my guess is that to reach that new equilibrium would take 100 years or more.  Then again, who's to say we would stop at 650ppm CO2 (even less likely for 650 ppm CO2e)?
   
     (Speaking of Dec and Poll 2016, the new paper does NOT account for their proposed ice cliff instability, which apparently is still being debated for validity.  If it does apply, then it seems the new study's melt rates would be underestimates by leaving it out.  On the other hand, the new paper mentions both negative and postive feedbacks that could affect this new disaster scenario.) 

     See animated simulation posted yesterday by Potsdam Institute: 
The Hysteresis of the Antarctic Ice Sheet
Sep 23, 2020


Journal article - The hysteresis of the Antarctic Ice Sheet
Julius Garbe, Torsten Albrecht, Anders Levermann, Jonathan F. Donges & Ricarda Winkelmann
Nature volume 585, pages538–544(2020)
https://www.nature.com/articles/s41586-020-2727-5
    New (to me) term - "Creep instability"   Good fit for the times.

39
Arctic sea ice / Re: The 2020 melting season
« on: September 19, 2020, 11:57:21 PM »
The reference was clear, 2012 vs. 2020 per the attached Hycom images.
   I agree that is what he said.  I was just trying to point out that he was applying the wrong starting year to the often-cited 75% decline in ASI Volume.

40
Arctic sea ice / Re: The 2020 melting season
« on: September 19, 2020, 08:02:18 PM »
     I think OTG reference to 25% of Volume refers to 2020 (or 2012) in comparison to 1978.

41
Arctic sea ice / Re: What's new in the Arctic ?
« on: September 18, 2020, 07:32:10 AM »
Wildfires in Arctic Circle release record amounts of greenhouse gases - BBC News

5 minute video, gives a ground level view of Siberia and some of the folks who live there.

42
Arctic sea ice / Re: The 2020 melting season
« on: September 18, 2020, 06:04:09 AM »
 
Here is a chart and table I prepared earlier this year based on PIOMAS volume data... <snip>
   
     Wow, Oren.  2007 is jaw dropping.  I mean, really.  If any of the experts are lurking around the ASIF this is the time to show your cards.  Calling Drs. Alley, Birkel, Box, Dethloff, Goose, Meier, Notz, Mayewski, Overland, Polyak, Scambos, Serreze, Shuppe, Stroeve, Wadhams, Zhang, and all the rest.  WTF, call Dr. Ruth too.  Sadly, Dr. Konrad Steffen is off-duty. 

      You can weigh in under a pseudonym if association with this scruffy lot is hazardous to your professional reputation.  Dr. A-Team, please report to the operating room!  Patient #2007 lost weight all winter and suffered heavy bleeding all summer!  We need a diagnosis.
     
     Assuming minimum Volume in 2020 will be no higher than 2019, a quick trip to Excel suggests that the Late Summer 2020 melt was ca. 9.02 M km3 which would be a new record, leaving 2012 in the dust (for that period). 

     ...and that the 2020 Summer Total melt would be ca. 19.01 Mkm3, just 0.26M short of 2012.  All that from an impressive GAAC and a short-lived semi-GAC in 2020, but without any lightening strikes like the GAC 2012.

     With the day 266 to 266 framing, 2012 takes a step back, and 2016 a step forward.  But 2007 is revealed to be a Monster Performance.  It was like Tiger Woods at the 1997 Masters Tournament just crushing the competition.  (That was more than golf, it was a great day for humankind at a private club that barred black golfers until 1975, but I digress...)

     I'm going to have to go back and re-read those Friv dipole posts from this summer.  Now I know why Neven, Friv and others get so itchy when it looks like a dipole might set up. 
Maybe we need a new Glossary entry:  Dipole = Atmospheric Ice Eating Monster. 

43
Arctic sea ice / Re: The 2020 melting season
« on: September 17, 2020, 10:31:56 PM »
Actually, I'd say the "flip" happened between 2007 & 2012.  Since then, I think we've just been working through latency in the system.
      The 2012 GAC gets lots of attention, which is justified for a freak event with high (though much of it shortlived) impact.  But I haven't seen as much discussion about the weather patterns that had already defined 2012 as a big melt year well before the GAC 2012. 

      Agreed, 2007 really was the starting gun. The more I've learned the more I've wondered "What the heck happened in 2007?"  ASI watchers must have been freaking out at the time because there were no precedents or early warning as far as I can tell.  It was a killer melt year from which the Arctic has never really recovered.  Discussion of the weather patterns or other factors that made 2007 such a drastic melt year would be appreciated by this reader, and I suspect many other ASIF denizens.
     

44
Arctic sea ice / Re: What's new in the Arctic ?
« on: September 17, 2020, 07:55:37 PM »
     Which led to this:  J.R. Mioduszewski, S. Vavrus, M. Wang, M. Holland, L. Landrum, Past and future interannual variability in Arctic sea ice in coupled climate models, Cryosphere 13 (2019) 113–124, https://doi.org/10.5194/tc-13-113-2019

     Abstract (bolding added and format edited slightly for clarity)

    "The diminishing Arctic sea ice pack has been widely studied, but previous research has mostly focused on time-mean changes in sea ice rather than on short-term variations that also have important physical and societal consequences. In this study we test the hypothesis that future interannual Arctic sea ice area variability will increase by utilizing 40 independent simulations from the Community Earth System Model's Large Ensemble (CESM-LE) for the 1920–2100 period and augment this with simulations from 12 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5).

     Both CESM-LE and CMIP5 models project that ice area variability will indeed grow substantially but not monotonically in every month. There is also a strong seasonal dependence in the magnitude and timing of future variability increases that is robust among CESM ensemble members.

     The variability generally correlates with the average ice retreat rate, before there is an eventual disappearance in both terms as the ice pack becomes seasonal in summer and autumn by late century. The peak in variability correlates best with the total area of ice between 0.2 and 0.6 m monthly thickness, indicating that substantial future thinning of the ice pack is required before variability maximizes. Within this range, the most favorable thickness for high areal variability depends on the season, especially whether ice growth or ice retreat processes dominate.

     Our findings suggest that thermodynamic melting (top, bottom, lateral) and growth (frazil, congelation) processes are more important than dynamical mechanisms, namely ice export and ridging, in controlling ice area variability."

     Graphic below is mean ice area from CESM model ensemble.  Of course this paper was written way back in 2018  8).  I think the Wipneus linear Volume trend projection for zero September minimum ASI by 2032 is a better predictor than the climate models which have been routinely late in their Arctic sea ice decline estimates.  No volume = no area.  But that's for another thread!

45
Arctic sea ice / Re: What's new in the Arctic ?
« on: September 17, 2020, 07:53:33 PM »
    Nice catch Juan.
    Some pithy quotes of particular interest to ASIF. 
     
     SIT = Sea Ice Thickness
    "Declines in SIT are particularly relevant for transpolar shipping, as the measure is a chief determinant of the type of polar class (PC) vessel required in ice-covered waters.  Like sea ice  extent, SIT has been declining: at the North Pole, while average SIT was ~4 m between 1958–1976, by 2011–2017, it dropped to <1 m. "

        CAO = Central Arctic Ocean
       "Commercial shipping will  require robust forecasts meeting more stringent criteria, such  as  the IPCC’s definition of “nearly ice-free conditions” when sea ice extent dips below 1 million km2 for at least five consecutive years, or seasonal benchmarks of 90 days or more of operational accessibility in the CAO.  In the near term, making such forecasts may prove challenging since sea ice variability is projected to grow substantially even as its total amount declines.  Nevertheless, in the  long term – i.e. by mid-century and more certainly by 2100 – ice-free summers are ex-pected to occur regularly, promising greater predictability for shipping lines."

      "The CAO may be ice-free in summer as soon as the 2040s, setting in motion the seasonal opening of the TSR.  Even if this sea change does not immediately reconfigure global shipping networks, already perceptible increases in the region’s economic activity suggest that preparations are in order."

     "...[T]he environmental and socioeconomic impacts of the TSR will be more acute at local rather than regional or global scales. While the shipping route promises new avenues for economic development, it may jeopardize the health of coastal ecosystems and vitality of subsistence activities.  Although the CAO is uninhabited, thousands of people live in communities along the Bering Strait, in Svalbard, and in northeast Ice-land where transshipment ports may be constructed and where large vessels could one day dock.  Particularly along the Bering Strait, com-mercial shipping threatens subsistence whaling, sealing, and fishing.  Empowering Indigenous and local communities to exercise stakeholder rights and participate in maritime policy forums for Arctic shipping while minimizing the industry’s negative impacts – and, if possible, finding a  way  that  development of the TSR could provide tangible benefits – is crucial."

     "Yet regardless of the ultimate extent of the TSR’s commercialization, the moment at which the Arctic becomes ice-free will mark a profound turning point in human and environmental history.  As warming and melting accelerate, regions like the Arctic that “had for centuries dramatized the fragility of human life have, in a few short decades, been refigured as representing the earth’s profound vulnerability to collective human agency”.  The increasing accessibility of the TSR epitomizes the  ambivalence of changes to the Arctic in the Anthropocene.  While the opening of a truly trans-Arctic shipping route is a symbol of mankind’s greater freedom of navigation, it also presents a stark reminder of the social and environ-mental costs of this freedom, the conditions that have given rise to it, and the sudden transience of a long-frozen region."

46
Arctic sea ice / Re: The 2020 melting season
« on: September 17, 2020, 07:07:48 PM »
AMSR2: Some recent days of 2020 compared to 2012
Rough overlay of 2012 vs 2020 using awi amsr2 v103, aug20-sep15 (am/pm)

gimp grain extract, the years were slightly different sizes so there is a small scaling error
     Nice graphic uniquorn.
     FWIW - Perhaps the difference between 2020 and 2012 can be summarized as:
                 
      Where 2020 had ice at minimum beyond the 2012 extent, that 2020 ice was thin, fractured, "low quality" (in terms of melt resistance).  Though I suppose the same could be said about the reverse, i.e. where 2012 had ice but 2020 didn't, that peripheral ice in 2012 was hardly pristine.
               
      And where both years had ice in the CAB, a good chunk of the 2020 CAB ice is in a weakened state, whereas in 2012 the central CAB was still pretty much the continuous, thicker (than 2020) ice pack of the pre-21st century Arctic which is no more.
               

47
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: September 17, 2020, 06:56:02 PM »
Whoops - corrected.
       Huh?  I'm still confused (not unusual in my case. Try it, you get used to it after a while).
     
       Here is the supposedly corrected statement at
https://forum.arctic-sea-ice.net/index.php/topic,2975.msg286733.html#msg286733
 
"Average remaining melt (of the last 10 years) would produce a maximum in Sept 2020 of 13.48 million km2, 0.40 million km2 below the March 2017 minimum maximum of 13.88 million km2."

       I think the correct correction would be:
      "Average remaining melt freeze (of the last 10 years) would produce a maximum in Sept 2020 March 2021 of 13.48 million km2, 0.40 million km2 below the March 2017 minimum maximum of 13.88 million km2."

      Is this right, or is there need to correct my correction of the correction?

      We nitpick because we care.  You only hurt the ones you love.  Ditto thanks to all the data providers for what has been a wild ride of a melting season.  I don't think Friv has even been so thrilled as he was this July.  At least somebody's happy!  And thanks to Oren we got through it with minimal umbrage and personal insults about our pet theories!

      I think there is truth in be cause's tag line:
"2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021"

      And I would add "+ 1 = 2022".  Seriously, the bus could be leaving the station.  The trend has been for changes to occur sooner not later than expected.  When's the last time you saw a climate change story about how things are evolving slower or less drastically than anticipated?   For those of you in the U.S., and everybody everywhere for your own elections, please vote and tell everybody you know to vote for climate rationality.  This infection has to be healed or it will kill us. (Sorry, I couldn't resist... I haven't had a good climate scream for awhile.) 

      Getting back to ASIF business, the path ahead for the coming freeze season, and especially the 2021 melt season, look to be "interesting" (in the Chinese curse sense of "May you live in interesting times", which we certainly are).   

48
Arctic sea ice / Re: The 2020 melting season
« on: September 08, 2020, 07:46:29 AM »
September 2-6.

2019.
     1. The Severnaya Zemlya ice pack lives!   :P   

     2. We all assume that there must be extra heat in the Arctic Ocean water due to high pressure -> clear skyies -> high insolation that dominated this summer.  But do we have any metric that tracks the amount of energy in the Arctic Ocean water?  GFS and DMI show 2M air temperature but that is not reflecting supposed extra heat in the water remaining from this summer.

49
Arctic sea ice / Re: The caa-greenland mega crack
« on: September 08, 2020, 07:03:23 AM »
https://forum.arctic-sea-ice.net/index.php/topic,119.msg285372.html#msg285372
Monthly update from the Polar Science Center:
Quote
August 2020 Monthly Update
<snip>
 Ice thickness anomalies for August 2020 relative to 2011-2018 (Fig 6) continue the pattern that has emerged over the winter, spring and shows relatively thin ice along the Russian Coast and thicker than normal in the Eastern Beaufort and the along the Canadian Archipelago.
    How does PIOMAS see thicker than normal ice on the north coast of Ellesmere when the AMSR2 shows a lack of land fast ice at same location for August 2020?  One of them has to be wrong.

https://forum.arctic-sea-ice.net/index.php/topic,2839.msg285417.html#msg285417
amsr2-uhh, jul21-sep6

50
Arctic sea ice / Re: MOSAiC news
« on: September 08, 2020, 06:47:21 AM »
     The year dates on the salinity graphic seem to be reversed.  It looks like reverse Atlantification from the first image (2019) to the second (2020).  For example, north of FJF goes from mostly red in 2019 to mostly yellow in 2020.

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