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Messages - jdallen

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1
...
The Beaufort sea cracks and sea ice in general may be refreezing at a good pace compared to last year even with no MYI. Cold temperatures and lack of movement again and perhaps thin ice negative feedback since January.
If some Beaufort sea ice survives this year, there may not be any record soon. It all, still, hangs on this summers weather.
(emphasis mine)
That's a lot of conditionals right there, seaicesailor. Back to the numbers/science, what is the trend? What is the statistical uncertainty associated with the data we have? What does it tell us?
It tells us that there is a high level of variability in potential outcomes. 

It is exactly that uncertainty that caused me to choose 2040-2050.  While weather may change, and we *will* see SIE bottoming out under 1 million KM2 soon, it will take far longer for net enthalpy to catch up such that we can expect ice to disappear in summer completely.

This does not indicate not one jot less concern on my part than yours for what's happening. It means I am thinking carefully.  Maybe you should make fewer value judgements about other participants, and perhaps consider the questions they pose. You could do worse than have some respect for that.

Have you thought for instance, how the ice might reach an end of summer SIE of greater than 1 million KM2 after 2030?  Your stridency suggest to me you have not.  I urge you to bring more light and less heat to the discussion.


2
Arctic sea ice / Re: The 2017 melting season
« on: April 20, 2017, 08:42:44 PM »
So much data saying Melt (DMI, Arctic anomaly, Fram export, destruction of  sea ice sheets integrity from multiple observations  etc. etc.). And yet jaxa sea ice decline remains at a glacial pace, and sea ice volume not declining yet.
And still at least 2 weeks before getting April PIOMAS  update. Am I the only one in confusion ?
I think the answer is dispersion, GC.  Less ice, spread more thinly.

3
Arctic sea ice / Re: The 2017 melting season
« on: April 20, 2017, 09:28:36 AM »
Browsing around tonight in worldview, there are hundreds of thousands of KM2 that look like they are right on the edge of vanishing; it's not just the Bering.  If  you look in the Kara, along the margins of the Barents, the Bering, the Okhotsks, Baffin, the Greenland, you will see huge expanses like that shown below. 

This image is from south central Baffin, and the image is about 250,000KM2 total.

4
Arctic sea ice / Re: The 2017 melting season
« on: April 20, 2017, 09:16:03 AM »
Look for major drops in extent in the Bering over the next few days.

5
I read the Booth paper quickly and it does suggest that HADGEM2-ES explains a part (but not all) of the 'bump' in temperature in the 30's-40's. Also, I understand that their HADGEM2-ES run is mostly driven by indirect (not direct) aerosol forcing. If I understand that correctly, it makes assumptions about cloud coverage affected by aerosols.

Now I'm not sure yet how important their findings are, but I do see that this paper (Booth et al) draws criticism in the scientific literature.

For example, here, by Zhang et al 2012 responds to Booth et al :
However, here it is shown that there are major discrepancies between the HadGEM2-ES simulations and observations in the North Atlantic upper-ocean heat content, in the spatial pattern of multidecadal SST changes within and outside the North Atlantic, and in the subpolar North Atlantic sea surface salinity. These discrepancies may be strongly influenced by, and indeed in large part caused by, aerosol effects. It is also shown that the aerosol effects simulated in HadGEM2-ES cannot account for the observed anticorrelation between detrended multidecadal surface and subsurface temperature variations in the tropical North Atlantic. These discrepancies cast considerable doubt on the claim that aerosol forcing drives the bulk of this multidecadal
variability
.

Don't you just LOVE science and the scientific process ?
Indeed; that said, it causes me to question somewhat the reference to that warming period as an indication of base-line "natural" increases driving Ding et. al.'s  conclusion, even if not responsible for *most* of the increase.

How would we eliminate human-sourced aerosols from baseline calculations of natural variability?

6
Quick off the cuff thought - I'm piqued by the idea the 30s/early 40s temperature bump could be a result of decreased aerosols (SO2 in particular) tied to the reduction in industrial zctivity and fossil fuel consumption during the depression.

7
Arctic sea ice / Re: The 2017 melting season
« on: April 18, 2017, 07:14:04 AM »
A stark illustration of how difficult our situation is.

Two daylight captures of the northern Bering, Chukchi, eastern ESS and Western Beaufort.

First is 04/17/2016

Second is 04/17/2017.

[Edit: Added for comparison, 05/17/2016]
[ADDITIONAL edit - I got the name stamps wrong on two of the images. 
From top to bottom:
2016-04-17
2017-04-17
2016-05-17
]

8
Arctic sea ice / Re: The 2017 melting season
« on: April 17, 2017, 05:16:03 PM »
Very difficult to vector that sort of mobility into any prediction for September.
What is frightening about these animations of the Beaufort and Chukchi is how fractured much of the ice is. Large portions look like rubble.
Both true statements.

Also true, 2017 open water in the Chukchi and Bering seas has caught up to and passed 2016 in almost a matter of hours.  Conditions appear extraordinarily volatile.

9
Arctic sea ice / Re: The 2017 melting season
« on: April 17, 2017, 07:33:31 AM »
Worldview is down. Uni-Bremen is down. So, I went with what I could get.
Beaufort 15th(left) vs. 16th
I highly recommend using the zoom.

Dramatic and massive changes.  It looks to be catching up with 2016 pretty rapidly.

10
Less heat, more light, everyone.  Prof. Ding has engaged us in a lively and productive scientific exchange to both explain the paper and hear our questions and criticism.

If you wish to convince him to abandon his findings, you must present compelling fact and arguments.  This requires patience and careful thought.  if you sought rapid results and gratification, I suggest you discard that expectation.

Your arguments will require:

1) work as thorough and compelling as his own and
2) time for everyone one (including the good professor) to digest it.

11
... if we want to have a good understanding while monitoring the comeback of Arctic sea ice. ...
:o
You are joking, right?
We are already committed to the complete and irreversible (on a human time scale) disappearance year round of Arctic sea ice.

That kind of makes me want to shut down the blog and forum, and build a big bunker. And so the narrative I tell myself (and hopefully others once I get back to blogging) is that what we need to fight for, is getting Arctic sea ice back after we lose it. Preferably prevent it from going ice-free all year round.

why would you intentionally attempt to assign a value of 'natural variability' to a dynamic system that is in the process of catastrophic collapse?  Is it because the collapse is not what you expected?

If it is all collapsing, there's not much sense in thinking about what the best way to do research is. Or post on a forum. And what I've said in reply to AndrewB.
Bunkers are attractive but in the long run ineffective.

I appreciate greatly Dr. Ding jumping into our discussion, even as I struggle to fully grasp the nuances of argument. His doing so is the quintessence of good scholarship.

While I generally understand his teams methodology, which in context of process seems sound, I am wrestling with the label "natural variation" to describe "unforced" departure from average.

That's a big bucket, and I'm wondering how much of that is anthropomorphic change outside of the Arctic translating into it. Perhaps, Dr. Ding, you could address that thought?

Last thought to Neven - even if we cannot recover the Arctic as it was,  we still must consider the potential loss of billions of lives due to climate change. That deserves our continued discussion.

12
Arctic sea ice / Re: The 2017 melting season
« on: April 13, 2017, 01:05:43 AM »
Given the forecast, we can expect more of that. I'll try and make an updated animation.

Edit: I still had the template from last year:
2017 Beaufort looks to be trying mightily to catch up with 2016's open water.  It becomes more clear looking at it in Worldview, where you can see in particular just how shattered the ice is.  There may be more coverage than last year, but it is not robust. The Amundsen Gulf in particular has disintegrated into a bowl of ice cubes.

13
Arctic sea ice / Re: The 2017 melting season
« on: April 12, 2017, 09:02:53 AM »
The latest Arctic Sea Ice News is out:

<snippage>

New work by an international team led by Igor Polyakov of the University of Alaska Fairbanks provides strong evidence that Atlantic layer heat is now playing a prominent role in reducing winter ice formation in the Eurasian Basin, which is manifested as more summer ice loss. According to their analysis, the ice loss due to the influence of Atlantic layer heat is comparable in magnitude to the top down forcing by the atmosphere.

This is an unexpected and very bad finding.

14
Arctic sea ice / Re: Arctic Image of the Day
« on: April 07, 2017, 08:34:14 AM »
Fragility of sea ice revealed by a topographic constraint: circular ice breaking area radiates from an island north of the Kara Sea: <snip>
Great Image, VeliAlbertKallio!

That demonstrates categorically just how vulnerable the ice is in that region.

15
Arctic sea ice / Re: The 2017 melting season
« on: April 05, 2017, 05:04:25 AM »
Baffin is really moving some ice lately.


Indeed.  Davis Straight is about 330 km wide at the narrowest there (on the Arctic Circle, thereabouts).  Measuring a big floe 17th to 23rd March which moved 100 km over those five days and assuming an average ice thickness of 1 metre gives an export of 6.6 cubic kilometres of ice per day.  That is darn a big ice-block to freeze, and quite a loss to the basin.  I've no data to tell whether this is in any way an unusual loss rate and how it compares, say, with Fram et al.  But it sure is an impressive number.
That movement is un-blocking ice coming out of Hudson's bay and opening the NW Passage up to pressure from tidal movement.

Looking at all of the exits - Bering, Barents, Fram, Baffin - it seems like a general "Un-corking" is taking place.

16
Arctic sea ice / Re: Latest PIOMAS update (March)
« on: April 05, 2017, 05:00:49 AM »
Adam Ash
Indeed!  A simple drag and drop of previous years shows the potential for a far-too-close-for comfort minimum.
That smells like a Blue Ocean Event.

The fat singing lady always makes her own damn mind  ;)
Indeed.  No prediction of Blue Ocean here until after I see the numbers at the end of May.  Far too much depends on weather and albedo.

17
Arctic sea ice / Re: The 2017 melting season
« on: April 04, 2017, 04:07:08 AM »
Last but not least, some detail using Aqua Modis bands 7-2-1 that shows just exactly what happens when that ice reaches the "scorching" Atlantic heat influx we've been watching for the last 2 years.

18
Arctic sea ice / Re: The 2017 melting season
« on: April 04, 2017, 03:51:30 AM »
Using aqua-modis band-31 day, here's what I call "March to the Exit" - MYI passing out the Fram and Victoria strait into the Barentsz and Greenland seas to its doom.

19
Arctic sea ice / Re: The 2017 melting season
« on: April 04, 2017, 03:29:22 AM »
The ice keeps pushing back against the open water southwest of Novaya Zemlya. Given the wind forecast I think it's going to ice over again, so no super-unprecedented on that score. But we'll have to see what happens after that (that region only opened after the first week of May for years like 2011 and 2012).
Nice having sunlight back to see what's actually going on.

Same time frame in Worldview suggests dispersion to me rather than any sort of freezing.

<click to animate>

20
Arctic sea ice / Re: The 2017 melting season
« on: April 03, 2017, 10:02:26 PM »
In addition to being  more susceptible to melt, the ice has less protection against export.
If it can flow this freely now, what about a month from now? Or two, three months from now?
I actually somewhat expect export to support extent - cause it to "run in place" - but reduce concentration.  I think the effects of export *now* will be more aparent *later* in the season, as in after June.

21
Arctic sea ice / Re: The 2017 melting season
« on: April 03, 2017, 09:28:37 PM »
JO, what "extent impacts" were you expecting?
<snippage>
<more snippage>
Will we see a rapid cliff once some condition is met because the ice is too thin to resist?
<and even more snippage>
I expect a cliff in 2-3 weeks as effective received insolation pushes past an average effective level of 3 KWH/Day/M2 at 85N and below. (Incident is already much higher). When that happens, the Barentsz, the Bering, the Kara, the Okhotsk and parts of Baffin and Hudson's bays will see dramatic melt backs.  We could see a solid week of century drops.

22
Arctic sea ice / Re: The 2017 melting season
« on: April 03, 2017, 06:27:22 AM »
IJIS has extent running in place.  It would appear dispersion is taking place.

Generated this quick animation from worldview using 12KM Sea ice concentration.  It doesn't give a lot of detail, but does demonstrate how the ice is spreading out - which unfortunately in the Barentsz means into rather warm water.

<click to animate>

23
Arctic sea ice / Re: The 2017 melting season
« on: April 03, 2017, 04:31:45 AM »
Year over year 2016 vs 2017 comparison of ice temps in the Hudson/Baffin and environs.

2017 pretty clearly has a lot more available heat sooner than 2016.  Entirely subjectively, the quality of the ice using visible light suggests to me the Hudson is 1-2 weeks ahead of (last years) schedule, in spite of low late season temperatures.

Palette is Sea Ice brightness temperatures 6KM 89V using the "rainbow" palette squashed to 182-277K

EOSDIS Worldview basic link: https://worldview.earthdata.nasa.gov

26
Arctic sea ice / Re: The 2017 melting season
« on: March 29, 2017, 11:16:58 PM »
When it comes to these temperature anomalies... which I've been watching since at least November... I really have to wonder how much they matter this time of year (over ice, in particular).

If there's a patch of the arctic where normally it is -40 C/F, but instead due to huge anomalies it is -10 C, so what? It doesn't melt, melt ponds don't happen... I feel like the thermodynamics don't change...  until it gets above freezing.

Do we expect anything to come of these high anomalies, where temperatures still stay below freezing?

Heat flux out of the ice ( if we assume linear force formulation -  flux proportional to ΔT) is a quarter roughly compare to normal... it takes four times as long to thicken at the same level..


... presuming enthalpy remains constant.  The problem is, we have heat flow from depth, such that below a given temperature threshold, the ice won't thicken at all, because heat is replenished at the water/ice interface faster than it can be transferred out of the ice to atmosphere.  At -10C, ice more than 1M thick will actually start melting from the bottom, given enough time.

27
Arctic sea ice / Re: Stupid Questions :o
« on: March 28, 2017, 06:37:18 AM »
All our lady friends might prefer that we make diamonds from the carbon. ;)
Pile upon pile of them. Millions, no billions of them.

If they became cheap because of excess supply, would they still want them?  ;)
Graphite is much easier.
Carbonates are easier still.

28
Arctic sea ice / Re: The 2017 melting season
« on: March 24, 2017, 07:31:52 PM »
I believe it to be a good possibility that the  Beaufort ice might be the only ice to offer any resistance to disintegration and melt this year. Everything else is ready to go already.


If we are depending on the Beaufort to be the strong ice for the upcoming melt season, we are pretty well screwed.
The Beaufort isn't thick enough.  Most of the ice there is under 2M.

29
And Rob, since you asked this question "I wonder what the authors were thinking when they drew their conclusions(?)", my answer is that they already had the preposterous claim that the disappearance of sea ice is mostly due to natural variability in mind, and just found the models and performed the simulations (which they call "experiments") that would somehow justify their a priori conclusion.

AndrewB - did you bother to read Eric Steig's comment at Stoat's?  What is with this constant character assassination of climate scientists in these threads lately?  I feel like I'm at WUWT.

So, we have a peer-reviewed paper by a plethora of well-respected and leading climate scientists that challenge your beliefs.  OTOH we have a few paragraphs by a non-scientist on a blog.  Occam's razor would lead you to believe the non-scientist's blog post is correct.  Good grief, Charlie Brown.
Careful how you apply that razor - it may be cutting things you want to keep. You've used an ad hominem argument against an ad hominem statement.

Criticism from non-professionals is still relevant when well founded.  The correct take on this should be, how well supported is the critique, and does it raise reasonable questions?

Pertinent to the first statement - a conclusion against paradigm does not necessarily establish any fact regarding the person (s) making it.  Who wrote a paper is fairly irrelevant.  What is relevant is its content.

That is what should be under discussion, not personalities.

30
Arctic sea ice / Re: The 2017 melting season
« on: March 22, 2017, 07:20:28 PM »

Like jdallen and Juan, my larger concern is the state of the ice poleward north of Greenland.  Since the 20th, in addition to the retreat from the Kara, there appears to be a general anti-clockwise rotation that is breaking up all of the ice around the pole from 85 degrees north. This is most evident on the Canadian side of the pole, but also seems to be appearing in the Russian side.

Sam

Welcome to the age of the "whole arctic gyre"

31
Arctic sea ice / Re: The 2017 melting season
« on: March 22, 2017, 07:38:24 AM »
EOSDIS image, aqua-modis, palette squashed to 230-255K, white to green/black (hottest)

The largest concentration of thickest MYI in the arctic lies in the center of the field of view, mostly between N. Greenland and the Pole.

It is fractured to a faire-the-well, poised to get pushed into the FJL/Svalbard/Fram killing ground, as it is pounded by the strong persistent westerlies roaring around the low pressure systems spinning into the CAB from the N. Atlantic.

Not a good way to start things.  I wouldn't expect to see ice like this until at least June.

(Edit: replaced the original screen shot as it turned the > 255K regions white.  Link:
https://worldview.earthdata.nasa.gov/?p=arctic&l=MODIS_Aqua_Brightness_Temp_Band31_Day(opacity=0.44,palette=green_1,min=228.7,max=256.5,squash),Coastlines&t=2017-03-21&z=3&v=-1178165.0457067718,-1091186.6011562506,1607114.9542932282,338317.3988437494
)

32
Arctic sea ice / Re: The 2017 melting season
« on: March 22, 2017, 07:20:33 AM »
A couple areas that are noteworthy today.

Indeed.  The Kara is just getting hammered and will continue to be for at least the next 10 days.  The Hudson starting to come apart is a little unexpected, and not at the same time.  Ice there in spite of recent cold temperatures has never had a chance to really set up and is quite a bit less solid and less thick than I've seen previously (which admittedly is only 5 years...).

Both breaking open will increase insolation uptake at a point very early in the melt season.

It implication of that from the Hudson is not that great.  Ice leaving the Kara is much more troublesome, as it will introduce heat at high latitude and eliminate ice which buttresses both the CAB and Laptev.  Admittedly the Barentsz is more important for the CAB, but it all works together, and without some integration we will see albedo reductions in the high arctic even with out melt ponds, as peripheral ice melts, and permits the main pack to disperse.

33
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 20, 2017, 10:04:17 PM »
Still not looking good for a recovery.
The trend is on the downward march I think.
Looks like March 7th was the record low maximum extent on record, at least by this measure.
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

I'd agree not - we've pretty much declared max - and I suggest we close this thread for the season.

34
...
Even if it is wrong, the scientific way to find out is publish and be damned. (or not damned)
...
Hi crandles,
Again, I am not even arguing about the scientific value of the Ding paper per se here, or how it was worded, or how many caveats it was filled with.

I am talking about giving the "merchants of doubt" an excellent basis for further delaying the urgent and radical emissions reductions policies that need to be put in place to avoid the worst consequences of global warming - including famines, wars, forced migration, etc, and the suffering and ultimately death that these will bring to hundreds of millions of human beings.

So, are you a moral human being first and (questionable) scientist second, or does your oversized ego take precedence? In the case of Ding and his nine(!) co-authors, it seems the latter.

"Science sans conscience n'est que ruine de l'âme." - Rabelais

Now, of course since they have already been published, they have legitimized the clearly false assertion that the year-round disappearance of Arctic sea ice which will occur over the coming few decades is mostly due to "natural climate variability". You could demonstrate that they are entirely wrong, de-construct all the fallacies in their tortuous reasoning, dissect their various logic mistakes, point to each and every dubious assumption they make in the paper, it wouldn't matter: they cannot be unpublished. And clearly, people with such an oversized ego are not going to retract themselves or even admit that they were wrong and wrote a piss-poor excuse of a climate science paper.
So there you have it.
Arctic sea ice is going to disappear over the coming years but now the takeaway from this man-made disaster is that it's mostly "natural climate variability". Crappy (un)science is the new normal.
Talk about improving communications between climate scientists and the general public!
Actually, I don't think they asserted most of the loss was from natural variation, and I suggest the philosophical discussion get moved to an appropriate thread.

35

Eric Steig, one of the authors of the paper, asks (thank you Jim Hunt for posting the exchange): “[Should we] Not [have] published the paper, lest we inadvertently help the “skeptics”?” The answer, imho, is pretty obvious.

IMHO the answer is pretty obvious that yes they should publish provided they put in appropriate caveats.
...

Hi crandles,
Actually the Ding paper is generously sprinkled with caveats. But that has never prevented the fossil fuel industry propaganda writers from running with whatever argument they could extract from any scientific or opinion paper that would feed their rhetoric. If you don't believe me, just check Jim Hunt's blog for how mainstream media is "reporting" on this Ding et al paper.

So, unfortunately, I don't agree with you. Responsible, intelligent adults don't feed the narrative that Arctic sea ice is melting because of "natural climate variability". This paper should not have been published. And I am not even commenting on its scientific value, which imho is below the temperature (in degrees Celsius) at which ice transitions from solid to liquid.
I think it was appropriate to publish  as long as it passed peer review.  It is dangerous to politicize research.

That said, I think it is behooves us and them to better delineate the source of that natural climate variability, as I expect climate change outside of the Arctic has affected it and shifted it's range of variation.

36
Arctic sea ice / Re: The 2017 melting season
« on: March 20, 2017, 06:11:40 PM »
Before we get too deep into melting season, would some of the more seasoned posters mind giving a handful of things they will be keeping an eye on over the next few months to judge how 'good' or 'bad' the melt is going?

This will be my (and I suspect some others) first melting season so it'd be nice to know what to expect in general, as well as what to watch coming from such an extreme freezing season.
Lots of good suggestions from others.

My favorites:

Sea surface temperatures
General dispersion and concentration
Circulation and transport of ice in the pack
Cloud cover and albedo

37
Arctic sea ice / Re: IJIS
« on: March 18, 2017, 10:21:46 AM »
Almost another century break today. We are back to lowest on record!
I think we'll see a few days of this; most of the extent around FJL and Svalbard is little better than slush and the western Kara not much better.  When that clears out the decline may slow... unless heat starts slamming the Bering and Okhotsk, which is similarly fragile.  *Then* (I hope) it will slow down.  Maybe.

D*mn this is bad.

39
As many have reiterated, the observed rapid decline of Arctic Sea Ice is not explained by present understanding of the function of the climate system. New insight is required.  “Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice” appears to be an interesting contribution to the discussion.
I agree, and admit I haven't digested the paper in detail yet, but am skeptical that some/much of what they attribute to "natural variation" which may actually be driven by climate change outside of the Arctic.  More later after I've done due diligence.

40
Arctic sea ice / Re: IJIS
« on: March 18, 2017, 01:36:42 AM »
With the sustained heat anomalies predicted by climate reanalyzer, plus the returning sun to the southerly stretches of the Arctic, would have to agree with you. Quite possibly an "emphatic" drop, bad news for later on given the albedo effect of the extra open water.


It's more than just the southernly stretches getting sun. According to http://www.athropolis.com/sun-fr.htm, 24 hour per day sunlight hits the North Pole starting tomorrow.

Indeed, but the incident angle will render it mostly meaningless until we get at least 10 degrees of elevation above the horizon.  Even then, it won't do a lot until/unless we get melt ponds, which above 80 probably won't happen until June.  I hope. :o

41
Arctic sea ice / Re: The 2017 melting season
« on: March 16, 2017, 08:21:52 AM »
Is there an artefact or is the ice in Kara and Laptev "thickening"? Look at the color change between those days, the 10-15.
I don't see it LMV; at least, I don't see anything that stands out enough to my eye to consider it significant.

42
Arctic sea ice / Re: Stupid Questions :o
« on: March 15, 2017, 06:10:41 PM »
Good responses, ktonine.

Jim, I think you are missing the intent of the models; they are not so much used to predict exact behavior as they are to give us a trajectory.  That by itself is actually sufficient for us to derive conclusions as to how we need to change our energy use and economic behavior, and give us yardsticks we can use to compare theory with observed behavior.

As to their relevance, most are run with past data (hindcast) to see how well they match previously observed behavior when given inputs for a past date.

I'm still not understanding what your objection is, beyond your feeling the models are not skillful enough for you taste. Mostly it's seemed semantic.

Lastly, I think a fundamental issue lies in the fact the system is chaotic.  It is possible even in the real world to get different outcomes in system behavior from the same starting conditions; differences will be small, but as with precision in any measurement they will add up such that even with "perfect" mathematics you will not achieve a solution that absolutely matches observed behavior.

43
Arctic sea ice / Re: The 2017 melting season
« on: March 15, 2017, 04:36:02 PM »
Ice drift forecast for tomorrow, Mar 16. Fram export same as today.
Image: https://www7320.nrlssc.navy.mil/hycomARC/arctic.html
And there we have 10-15000 KM2/day of MYI getting drop-kicked out of the Arctic.

44
Arctic sea ice / Re: The 2017 melting season
« on: March 14, 2017, 10:51:31 PM »
You have to wonder if the thick ice above the CAA isn't the product of numerous compaction events. It seems to break up if you look at the wrong way. It just doesn't seem dense or homogeneous like MYI should be. If that is the case, there may be even less MYI left than we thought.
No doubt about compaction as the ice has been mobile.

I credit the warmer ice temperatures as responsible for the ice's apparent friable condition.  It loses mechanical strength  rapidly as you get above -30C or so.

45
Arctic sea ice / Re: The 2017 melting season
« on: March 14, 2017, 10:06:15 PM »
... Are we going to have much of the thin ice on the Atlantic side of the Laptev Sea melted out and exposed to peak insolation by around the Summer solstice?
It's quite plausible though far from certain.

What I noted was the rapid melt in the western Kara. That retreat could amplify changes in the Laptev and Barents.

The ice exiting the Fram does appear to be from exactly the densest remaining MYI in the basin aside from that packed along the CAA.  Hard to think of worse ice to have destroyed this early in the season.

46
Arctic sea ice / Re: The 2017 melting season
« on: March 14, 2017, 06:08:14 PM »
That "bomb" is currently giving 30CM of snow to my sister near Boston...

47
Arctic sea ice / Re: Stupid Questions :o
« on: March 14, 2017, 05:59:38 PM »
Let me phrase my stupid question a slightly different way.  What evidence do we have that we are using the right kind of mathematics for predicting what will happen in a discrete discontinuous system over a long period of time?  (Long being over about a month.)
Kinda rhetorical, Jim, but we don't. What we have is the output of the models themselves.

I really don't think the reduction of skill with time is a result of the math. I think it is a result of the inputs, their granularity, and our understanding of the system mechanics.

48
Arctic sea ice / Re: Stupid Questions :o
« on: March 14, 2017, 03:32:12 AM »
This is as much ice as we are going to get.

Based on what? It's only mid-March. According to PIOMAS, ice volume typically grows into mid-April - so another month or so.


I think Cid's - and my - point is, we're going to top out a little early, and possibly quite low - right around 20/21K KM3 for max volume.  I'm figuring things to end up at least 2K KM3 below the previous low volume record.

49
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 13, 2017, 10:22:20 PM »
DMI now shows temperatures back up 5-7C above normal (250-255K). It is now too late for cold temperatures to permit a recovery in volume.

In another 10 days we start the sharp spring climb in temperatures as the sun returns.  The current and coming storms pretty much preclude any serious return of cold weather.

What we have is about what we are going to get, ice-wise.

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Arctic sea ice / Re: The 2017 melting season
« on: March 13, 2017, 05:47:04 AM »
My only thoughts at this point are in regard to the water under the ice, as I do not know much about downward long wave radiation. Could it cause surface melt on the ice without heating the air?
There'd have to be an awful lot of it, and it by nature would raise air temperatures as well, so no, I don't think you'd get surface melt without increasing air temperatures.

Bottom melt is a different issue, and with temperatures above -20c, we're looking at their being enough excess heat flow through the ice that some of it would get captured as phase change.  The ice won't disappear as surface temps are still well below freezing, but the balance of heat flow means any ice much over a meter thick may have to contend with dynamics that prevent enough heat passing through the ice to prevent it from melting.

The balance would get restored as you reduce the thickness and permit greater heat flow.  At this stage any melt would be measured in a handful of CM at most.

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