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Tigertown

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Re: The 2017 melting season
« Reply #2750 on: July 11, 2017, 07:59:57 AM »
S.Pansa,
Quote
Unfortunately, I am more and more convinced that the TOPAZ4 system is not a good way to compare different years. I hoped so, but I don't think it does
Yeah, I am kind of thinking it is on the low side. The GOPAF may just be their better model, for thickness if nothing else. It seems to be closer to reality.
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Neven

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Re: The 2017 melting season
« Reply #2751 on: July 11, 2017, 08:02:23 AM »
Are we sure about the reliability of any data sources?

It's not just about the reliability per se. It's also about whether a data set can be used for interannual comparisons. Is it consistent enough, or have changes been made along the way?
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gerontocrat

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Re: The 2017 melting season
« Reply #2752 on: July 11, 2017, 11:37:42 AM »
There is a good chance this year will not see any SIE records, but hold the Champagne corks.
Consider: Oren's extrapolation of PIOMAS's daily numbers. It looks like a very strong possum-bility that this year's volume will come close or below those of 2012 as the melt season ends.
First thought might be that such a thing is not a big deal, but couple that with a higher than expected SIE, and voila, you have a super abundance of thin ice going into freezing season. If the upcoming season proves to be anything like the last, the scenario is the perfect setup for disaster. I really don't think that the individuals that keep pointing to the SIE and the rate it is dropping, have thought this out very well.

P.S. Don't forget, the CAA will probably be open again, and there may be trouble getting some of this loose ice to stick and not flow on through. The weather may get a little more unsettled by then.

As an individual pointing at Jaxa SIE measurements constantly I would agree that a scenario of high SIE coupled with very low volume obviously results in a very high area of thin ice going into fall and winter 2017-2018. (2012 saw of lot of area/extent reduction at the end of the melting season and voila, multo freezing winter 2012-2013). I assume that a great deal of thin ice will tend to hold in ocean heat content and inhibit ice thickness increases.

In other words, the point for me is to look at both volume and SIE and wonder for how long extent can reduce at an average of 13% per decade while volume declines at an average of 20% per decade. I am increasingly confident that the break is not happening this year. Using JAXA data, on average 60% of the extent reduction has happened by July 10, and this year is 7% below the 2007-16 average. Combine that with a record or near record low volume and average thickness....? Add that to a winter spring comparable to 2016-2017 and .....
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Thawing Thunder

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Re: The 2017 melting season
« Reply #2753 on: July 11, 2017, 12:52:40 PM »
Everything is speculation ...

« Last Edit: July 11, 2017, 01:29:25 PM by Thawing Thunder »
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F.Tnioli

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Re: The 2017 melting season
« Reply #2754 on: July 11, 2017, 12:58:12 PM »
...
Last year, someone proposed that the ice pack was going to split in two, north of Wrangel. That got a lukewarm reception on the melt season forum but almost came to pass. I wondering if that could happen this year but closer to the CAA.
...
I had this very same thought about a month ago, but now i don't: for that to happen, we'd need two real big halves, but it seems Pacific side won't allow us to have its own half (if separated) as anything more than pityful most thin and dispersed remains far not worthy of a "half of Arctic sea ice" proud name. This is totally IMHO and "what can i know" thing though, of course.
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Re: The 2017 melting season
« Reply #2755 on: July 11, 2017, 04:05:17 PM »
Thomas,
You are right that ACNFS Hycom images are shown often on the forum.
But the year-to-year comparisons are really not that reliable.
For example, I understand that the 2012 image was produced by a different version of the model.
You are comparing apples and oranges with that 2012-2017 comparison.
Yes, I did suspect that. Thanks.
I would go as far as to say 2012 is such an anomaly, all of the research groups were wrong for some reason. They were all still developing (and still are), and I think it was over-blown. Probably still the record, but maybe not as bad as it looked. I think 5 years later, all of the systems will have improved a lot.
« Last Edit: July 11, 2017, 06:22:41 PM by Thomas Barlow »

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Re: The 2017 melting season
« Reply #2756 on: July 11, 2017, 04:07:07 PM »
A follow-up to the last post. This is thickness on July 1st, 6th, and 11th. Also, projected thickness for the 16th and 20th. Notice that thickness and volume go down, while extent takes only a minor hit.
CLICK IMAGE


Whoa. That seems very dramatic.

Tigertown

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Re: The 2017 melting season
« Reply #2757 on: July 11, 2017, 04:48:21 PM »
As Wipneus points out from time to time, on occasion area drops more than extent, lowering concentration. Also, sometimes ice simply looses some of it's thickness to bottom or top melt. Patience is in order on our part in waiting on the next PIOMAS report, so as to know exactly how much melt has and is going on.
Here is Polarview concentration. Warmth, insolation, waves, and humidity have worked on the ice in the Chukchi and ESS,  among other areas.
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Thawing Thunder

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Re: The 2017 melting season
« Reply #2758 on: July 11, 2017, 05:12:35 PM »
Patience is in order on our part in waiting on the next PIOMAS report, so as to know exactly how much melt has and is going on.

While there that beautiful violet butterfly can be seen so clearly, and who knows if he stays or flies away ... but what does us make so sure that PIOMAS does have the correct data, as volume and thickness is so difficile to asset?
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Re: The 2017 melting season
« Reply #2759 on: July 11, 2017, 05:26:17 PM »
This shows one week of change from DMI.
July 3- 10th

subgeometer

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Re: The 2017 melting season
« Reply #2760 on: July 11, 2017, 06:05:58 PM »
Once the pack in the Arctic itself starts splitting in chunks it can't be long to game over. Deep gulfs between arms went close last year.

Here is an area of low concentration ice stretching from the open water in Chukchi sea through to at least 81N on worldview  today.

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Re: The 2017 melting season
« Reply #2761 on: July 11, 2017, 07:20:01 PM »
Also, sometimes ice simply looses some of it's thickness to bottom or top melt.

As measured by two ice mass balance buoys. 2017A at 77.04 N, 155.20 W

Air Temp: -0.8 C
Ice thickness : 79 cm
All Snow Melted
Ice Surface Melt: 21 cm
Ice Bottom Melt : 19 cm



2017B at 85.02 N, 4.91 W

Air Temp: 0.8 C
Ice thickness : 155 cm
Snow Completely Melted
Ice Surface Melt 10 cm
Ice bottom melt : 27 cm

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Tigertown

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Re: The 2017 melting season
« Reply #2762 on: July 11, 2017, 08:15:07 PM »

While there that beautiful violet butterfly can be seen so clearly, and who knows if he stays or flies away ... but what does us make so sure that PIOMAS does have the correct data, as volume and thickness is so difficile to asset?
Maybe info like Jim Hunt just shared above this comment. Else, somebody on location needs to check from time to time.

From http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/

Quote
Comparisons of the model estimates of the ice thickness with observations help test our understanding of the processes represented in the model that are important for sea ice formation and melt.
Also,
Quote
This time series of ice volume is generated with an updated version of PIOMAS (June-15,2011).  This updated version improves on prior versions by assimilating sea surface temperatures (SST) for ice-free areas and by using a different parameterization for the strength of the ice. Comparisons of PIOMAS estimates with ice thickness observations show reduced errors over the prior version.


« Last Edit: July 11, 2017, 08:21:56 PM by Tigertown »
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magnamentis

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Re: The 2017 melting season
« Reply #2763 on: July 11, 2017, 08:41:53 PM »
A follow-up to the last post. This is thickness on July 1st, 6th, and 11th. Also, projected thickness for the 16th and 20th. Notice that thickness and volume go down, while extent takes only a minor hit.
CLICK IMAGE


basically did not really want to blow that horn again so at least i make it short :-)

i have a strong feeling that while we all look at things from above ( extent = two dimensional surface image ) the real carnage to the already poor ice is done from below. something is looming below the surface and if that is true things will desintegrate over wide areas from one day to another without any obviouls reason weather, insolation and wind wise.

i think someone else mentioned a similar thought lately, that one day it won't matter any more how the surface behaves, ice will just evaporate into air like my earlier example of a frozen lake in the evening and all ice gone in the morning when the ice was only thin enough.

EDIT: since others often find better words to describe the same or similar thought and events, read this, the above is meant along the same lines:

http://forum.arctic-sea-ice.net/index.php/topic,327.msg120341.html#msg120341

Frivolousz21

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Re: The 2017 melting season
« Reply #2764 on: July 12, 2017, 06:55:24 AM »
A beast warm front has started to plow through through the ESS and Chuchki. 
The front comes with very warm moist air and clear skies with a transient but highly anomalous ridge.

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seaicesailor

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Re: The 2017 melting season
« Reply #2765 on: July 12, 2017, 10:22:16 AM »
What doesn't seem transient is the very anomalous depression over Greenland. It is enormous and will stay put, big change.

Bill Fothergill

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Re: The 2017 melting season
« Reply #2766 on: July 12, 2017, 11:04:20 AM »
Perhaps it's time to switch to a lower value bin (currently 4.0 - 4.5) in the poll for the Arctic SIE September average SIE. Quoting a well-known scientist speaking to the UK's Independent in an article dated 4th June...

"My prediction remains that the Arctic ice may well disappear, that is, have an area of less than one million square kilometres for September of this year,” he said.

“Even if the ice doesn’t completely disappear, it is very likely that this will be a record low year. I’m convinced it will be less than 3.4 million square kilometres [the current record low].

I think there’s a reasonable chance it could get down to a million this year and if it doesn’t do it this year, it will do it next year."


So there!

Oh, hang on a minute! That article was dated 4th June 2016.
Oh, hang on another minute! It's Peter Wadhams again!

http://www.independent.co.uk/environment/climate-change/arctic-could-become-ice-free-for-first-time-in-more-than-100000-years-claims-leading-scientist-a7065781.html

For those readers relatively new to this topic, and therefore perhaps less familiar with the "extreme" views mooted by some of the Dramatis personæ, here is another early offering which refers to the "ice free by 2013" claim...

http://news.bbc.co.uk/1/hi/7139797.stm


As there is currently only about 400k covering '07, '10, '11, '12, '13, '14, '16 & '17, a record low SIE is still certainly possible - especially in the light of last winter's lack of FDDs. However, I think the boat has well and truly sailed - at least as regards anything truly spectacular happening this year.

Although June SIE on its own has heretofore proven to have had little predictive skill as regards the annual minimum, I think that this will change one year soon. The thinning (and warming) ice results in all sorts of f/b mechanisms (reduced structural integrity and mechanical strength, increased mixing with warmer water due to turbulence, wave action abrasion, loss of previously landfast MYI, greatly increased ease of transport to the killing zones, etc, etc) and one year soon, we'll see a really low area/extent by the end of May. Given that peak insolation obviously coincides with the June solstice, that will be very bad news indeed.

There was one comment made by Prof Wadhams about a decade ago with which I have always been in total agreement...
"In the end, it will just melt away quite suddenly. It might not be as early as 2013 but it will be soon, much earlier than 2040."

The bit about "it will just melt away quite suddenly" is getting closer, but it's not going to be this year.


F.Tnioli

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Re: The 2017 melting season
« Reply #2767 on: July 12, 2017, 01:18:14 PM »
...
The bit about "it will just melt away quite suddenly" is getting closer, but it's not going to be this year.
You can't know this for sure, Bill. Nobody expected the GAC in 2012 to clear as much sea ice as it did, but it happened. Who said we can't have couple even stronger GACs this season August/September? And it ain't like 2017 overall is a _colder_ year than 2012, - quite the opposite, i believe. So, couple GACs each being stronger than 2012's seem to be possible in principle, and they'd clear lots and lots of ice because of how fragmented and thin it is this year.

And i really don't like what i see about bottom melt part presented by two buoys (few posts above), - both show rapid bottom melt but most importantly, last couple weeks, that bottom melt is clearly accelerating. If this trend continues, there might be not that much ice left by the beginning of September for a GAC to deal with.

That said, chances are indeed we won't see Blue Arctic this season. Can be argued it's not much likely we'd see record-low year (extent, area, volume), even. But to completely deny those possibilities? I think it's way too early to do so, yet. Two more months of melting weather which is known to be impossible to reliably predict for longer than a few days, you know?
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Re: The 2017 melting season
« Reply #2768 on: July 12, 2017, 01:29:58 PM »
I think it's not about Extent per se, rather about actual, factual Volume.
Not about satellite- measured Volume with myriad Artefacts and False Positive Anomalies.

That all being said, the Jetstream is already going almost meridional in Circles, resulting in a perpetual positive Feedback.
If we dodge the Methane Gun firing this Year it will be due to some remaining Slush & Ice Cubes in the ESS & Kara.
I don't think it takes all the Arctic Ice to disappear to result in a giant CH4 Burp from the ESS or Kara. As they are too peripheral, shallow Seas.

Tigertown

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Re: The 2017 melting season
« Reply #2769 on: July 12, 2017, 01:39:16 PM »
The records are not important. The question is; what kind of ice will be left in the Arctic going into freezing time? Think just for one second about the worst storm we saw last winter, right in the heart of winter. Now, imagine that or worse happening to the scraps that will be left this year. No melt season needed.
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Re: The 2017 melting season
« Reply #2770 on: July 12, 2017, 01:49:01 PM »
In the unlikely event there is a total melt out, do we close this thread as complete and create a new one for the summer season?

NeilT

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Re: The 2017 melting season
« Reply #2771 on: July 12, 2017, 02:08:46 PM »
...
The bit about "it will just melt away quite suddenly" is getting closer, but it's not going to be this year.
You can't know this for sure, Bill. Nobody expected the GAC in 2012 to clear as much sea ice as it did, but it happened.

True, but, in the end, to get blue ocean you need a massive drop in volume, area AND, critically, extent; In order to get there.

We know what the average melt from this time to the end of the melting season is and we know what the maximum ever has been.  I'm not going to delve into the figures but I'm pretty sure that even if we doubled the max melt, from now to September, we'd still be outside the blue ocean event that is anticipated.

I think Bill is quite right that we're pretty sure we're not going to see a blue ocean event this year.  Even with the shocking state of the ice right up to 85N in some places, the rubble nature of the Atlantic side, the deep penetration of open water areas on the Pacific side and the fact that it is very likely that all the peripheral ice will melt out.

That's not to say that I am not expecting more than average melt.  I am.  I just don't expect it to drop off the cliff just yet.

[Edit].  Let me correct that.  Yes if melt doubled we'd see a blue ocean. But below 150% and we'd still be above that.

It certainly doesn't look like it now although the ice north of the ESS and Chuchki is getting that "smoke on the water" look it had in 2012.
« Last Edit: July 12, 2017, 02:20:13 PM by NeilT »
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Re: The 2017 melting season
« Reply #2772 on: July 12, 2017, 02:37:22 PM »
Im at 3.7m but 4m is what id reckon if things continue the way they are. We shall see. Maybe some late melt will get down to 3.7m

Certainly I just cannot see a record this year.

But again a GAC event could change that

F.Tnioli

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Re: The 2017 melting season
« Reply #2773 on: July 12, 2017, 04:23:02 PM »
NeilT, it is exactly that: double average melt rates and it'll be Blue Arctic, but 150% of average melt rates from now till early September - would not be exactly enough. I know that. But to me, that's not an argument against what i said above. Here's why.

Thing is, it seems you and Bill are both missing one most simple fact of ice melting process: it accelerates much (with everything else being the same) when ice concentration drops below 50%. Weather can both delay and accelerate "remaining melt" dramatatically at any given time and location, of course, even reverse it to freezing sometimes; but with "everything else the same", low-concentration areas will melt times faster than solid pack ice at near 100% concentration, which is why so many here are concerned about state of the ASI this season.

The most simple and obvious evidence comes from simple observation: a piece of ice allowed to melt while placed into non-changing melting environment. Here's a of the process. As you can easily see, after 15 seconds of the video, the piece still keeps its form, and its "area" is still more than a half of the area of the initial size, and its "extent" is pretty much 100% of the initial extent (assuming the piece is less in size than 1 satellite grid cell). Then the melt starts to accelerate visibly, bit by bit. 0:20 mark of the video, - is nearly where we're now in terms of this season, if i might add. Still, by 0:20, the piece still has its distinct shape and still occupies much of its initial size area and especially extent (still more than the "standard" 15%, so in NSIDC terms, that piece is still a part of 100% extent ice, eh). But the melt accelerates further, and by 0:25, much more than a half of remaining by-0:20 ice is gone, and all of it melts away by 0:29 mark of the video.

This means, you can't expect linear melt rates to be the case all the way to "0.0 thicknes / extent" situation. There is a point which can be designated as "less than a half than normal amount of ice left", after which melt rates will increase massively.

In 2012, we had, in my opinion, the 1st case when large parts of ASI went beyond this point; the GAC did so much damage exactly because there was little enough ice in its path for this natyural mechanic to kick in and help the GAC to melt lots of ice. Fortunately, 2012's melt season happened to end very soon after the GAC, plus 2012 had much of ASI still being relatively strong in other areas, wouldn't melt so easy.

This season, though, it's much worse. Which is why GAC(s), if they happen late in the season, are likely to clear much more ice than some people anticipate they would.

The above is the 1st mechanic (higher melt rate when "too little" ice is remaining), but not the only. The other big one "in the room" is that melt season, depending on weather, may last significantly longer than it usually does. The overall ASI _melt_ week some time during November 2016 is an excellent indication that this is possible, given weather which assists with it.  If the melt season lasts till the beginning of October this year, for example, - then your "150%" rate will be quite sufficient to see Blue Arctic event at the minimum.

Overall, apart from the GAC of 2012 demonstrating _substantial_ effect of described mechanism in practice, the Arctic and especially the CAB has so far never demonstrated to us how quick "finishing touches" before the Blue Arctic event may happen. However, field scientists who see how ice melts in practice daily for many years of their life - they know this is real at least intuitively, but also often very consiously, too. This is why you so often hear field collegues reporting all kinds of "fear" that seemingly abrupt, sudden change may happen: they've seen this kind of "big acceleration near the end" in all sorts of melting processes, on mighty different scales, with their very eyes. Much like we see that ice cube accelerating its melt in the video above.

P.S. The above video with the ice cube is simplest, but not the best explanation for the acceleration of melt rates at "final" stages of ASI meltdown towards Blue Arctic. The better one -
 is this: the more thin and more fractured ASI gets, the bigger total surface of ice-water boundary relative to remaining ice volume forms up. Due to always present imperfections in ice and fluctuations of salt content, ongoing melt creates "canals" and "complex surfaces" within remaining ice, which further increases said ice-water border surface (again, relative to remaining volume) total. This increasing ratio affects direct heat exchange intensity between remaining ice and water, plus leads to higher percentage of remaining ice volume to be penetrated by any given same level of IR radiation, which both lead to faster melt rate for remaining ice. This is why there is ever-present acceleration of melt rates "with everything else being the same" - a positive feedback very "built-in" into very process of melting ice. 
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Re: The 2017 melting season
« Reply #2774 on: July 12, 2017, 04:55:10 PM »
Let's keep it on-topic as possible, and as short as possible. And let's try to add images.

People come here for quick info on how the melting season is progressing as we speak. Not to read a book.
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Re: The 2017 melting season
« Reply #2775 on: July 12, 2017, 05:49:26 PM »
It will be interesting to discover if the models predicting sea ice extent seasonal lows based on 1) melt pond fraction; 2) land snow cover, or 3) other factors, turn out to be on target during this unusual melting season. A metric that caught me off guard by how little predictive value it seems hold is the SIE as of 7/11 (based on NSIDC Chartic - day 192 in 2017) as shown in the graph below, the Arctic SIE is in a very tight range in 2007, 2010-14, and 2016-2017 on this date. The divergence in extent does not seem to occur until August.

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Re: The 2017 melting season
« Reply #2776 on: July 12, 2017, 08:03:55 PM »
It will be interesting to discover if the models predicting sea ice extent seasonal lows based on 1) melt pond fraction; 2) land snow cover, or 3) other factors, turn out to be on target during this unusual melting season. A metric that caught me off guard by how little predictive value it seems hold is the SIE as of 7/11 (based on NSIDC Chartic - day 192 in 2017) as shown in the graph below, the Arctic SIE is in a very tight range in 2007, 2010-14, and 2016-2017 on this date. The divergence in extent does not seem to occur until August.

[On topic in bold.  ;-)]

I was ignoring 2013, in which case the bottleneck is a few days ago.  2013 started above the bottleneck and ended up with "high" extent; 2014 went through the bottleneck.  Of course, 2015 started above the bottleneck and finished in the middle of the pack, so that line is kind of cherry-picked.

We might consider 2013 to have started diverging in late July.  Buy, yeah, ignoring 2015, the lines have separated into low, medium, and high groups as early as about August 7.  With 2015 included, we might wait until August 12 to make a prediction.

Right now it looks to me like 2017 is trying to slow down and follow 2010 to try and provide more evidence for someone's prediction about snow cover's effect on ice melt...  But in order to keep the signal to noise ratio low, I'd expect 2017's line to bounce around and create a lot more line crossings.   :)

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Re: The 2017 melting season
« Reply #2777 on: July 12, 2017, 09:17:29 PM »
The bit about "it will just melt away quite suddenly" is getting closer, but it's not going to be this year.
My prediction is that many people will say this every year (and have said it every year -- 100% hindsight accuracy!  8) ), and that every year they will be right.

Until they are massively wrong. That's the giant downside risk that conservatism poses to conservation.

But what I really wanted to post (OT again  :-[ ) is: http://www.bbc.com/news/science-environment-40321674
« Last Edit: July 12, 2017, 09:23:18 PM by greatdying2 »
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

greatdying2

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Re: The 2017 melting season
« Reply #2778 on: July 12, 2017, 09:22:19 PM »
And here's an image for Neven  ;D ;D
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

pauldry600

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Re: The 2017 melting season
« Reply #2779 on: July 12, 2017, 09:27:48 PM »
At last Neven said that

A great forum but not a book as you say

Today was 4th Century break of JAXA SIE season

I only can do short posts as dunno how to post images

greatdying2

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Re: The 2017 melting season
« Reply #2780 on: July 12, 2017, 09:43:00 PM »
I only can do short posts as dunno how to post images
Just click "Attachments and other options" below the text box (where you type), then click "Choose File", then choose an image file. (If you want more than 1, click "more attachments".)
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

Tigertown

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Re: The 2017 melting season
« Reply #2781 on: July 12, 2017, 09:58:34 PM »
NSIDC SIE
X 106 km2

2017,    07,  09,      8.657
2017,    07,  10,      8.591
2017,    07,  11,      8.434

That's a 157k drop on the last one.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Thomas Barlow

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Re: The 2017 melting season
« Reply #2782 on: July 12, 2017, 10:07:12 PM »

werther

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Re: The 2017 melting season
« Reply #2783 on: July 12, 2017, 10:52:48 PM »
The Larsen calving is not the defining event of today's state of affairs. It is the relentless demise of Arctic sea ice cover.
MODIS today yet again shows the actual sad state of ice quality out there. wadham's prediction doesn't have to be staved by the numbers. These remains could be wiped out any time when conditions get severe.

Thomas Barlow

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Re: The 2017 melting season
« Reply #2784 on: July 13, 2017, 12:22:56 AM »
The Larsen calving is not the defining event of today's state of affairs.
My point exactly. So why did you talk about it here? ... again  :)

Hyperion

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Re: The 2017 melting season
« Reply #2785 on: July 13, 2017, 01:14:38 AM »
Finding it real hard to find gaps in the clouds to get decent views of the state of the ice in the central basin. But after a few hard hours of scanning thru terra modis, aqua modis and suomi imagery, and a bit of contrast and brightness tweaking heres a selection. As is obvious from these 80 to 90 degree north shots there seems little more than rubble up there. except possibly in the compression zone up against the CAA garlic press.

I suspect some unforseen mechanisms may be cutting in with the early opening of the chuckchi and Northern european coasts relative to their snow melts, and stormy conditions. Could this be mixing gulfstream waters, incoming pacific waters, and warm riverine outflows with the low salinity surface water of the greater basin as they pass over shallow continental shelf areas? causing an increase in incoming waterbourne energy staying near the surface?
Certainly the fetch for wind initiated current and chop in the large gaps between the loose packed rounded off floes over the majority of the ocean is enough to generate more mixing than has been seen before also. This is not an Arctic ocean that any models predicated on past observations can pin a tail on. And that includes things like precipitation predictions by models like Nullschool. The complexity and rapid change in the cloudtop shapes indicates a massive amount of local weather events going on out there.
« Last Edit: July 13, 2017, 01:25:01 AM by Hyperion »
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

Bill Fothergill

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Re: The 2017 melting season
« Reply #2786 on: July 13, 2017, 01:29:52 AM »
...
Thing is, it seems you and Bill are both missing one most simple fact of ice melting process: it accelerates much (with everything else being the same) when ice concentration drops below 50%.
...

Perhaps you didn't notice the bit where I said...
"The thinning (and warming) ice results in all sorts of f/b mechanisms (reduced structural integrity and mechanical strength, increased mixing with warmer water due to turbulence, wave action abrasion, loss of previously landfast MYI, greatly increased ease of transport to the killing zones, etc, etc)"

As regards the impact of GAC2012, it is worth having a look at the numbers. The first thing that should be noted is that this GAC really kicked off around August 5th, and, by that date, the NSIDC extent value was already about 300k lower than that clocked up on the equivalent 2007 date.

During 2007, the mean value of the NSIDC Sept dailies was about 1.8 million sq kms lower than the 5th August value. During 2012, the equivalent drop was 2.2 million sq kms - an increase of only around 400k.

Looking at the PIOMAS numbers for those two years can be more revealing. For 2007, the July and September average values were 12,119 kms^3 and 6,526 kms^3, giving a drop of 5,593 kms^3. The equivalent 2012 values were 9,264 kms^3 and 3,787 kms^3, giving a drop of 5,477 kms^3.

In other words, despite the effects of GAC2012, the volume drop from July to September (according to PIOMAS) was marginally less than that experienced during 2007.

I therefore think that, in order to achieve the kind of disastrous melt-out during the 2017 season that some people are anticipating, it is going to need more than just a couple of juiced up GACs .


I have appended some rough PIOMAS projections, the first using a 2nd-order polynomial trend line, and the other with a simple linear trend. It is worth having a look at when the various projections intersect the X-axis.

Tigertown

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Re: The 2017 melting season
« Reply #2787 on: July 13, 2017, 03:46:41 AM »
GOP-A&F Sea Ice Concentration from June 13th to July 13th in three day intervals, and projections for July 16th,19th, and 21st.
CLICK IMAGE
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Hyperion

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Re: The 2017 melting season
« Reply #2788 on: July 13, 2017, 03:53:59 AM »
A few less clouds today on the Terra-Modis images for the 12th. Nth pole at bottom right corner. Franz-Josef land at top left. Still veil of fog or cloud over most. gives that wavey mottled look. A few spots where there is none and the ocean between the floes stands out nice and dark though.
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

Shared Humanity

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Re: The 2017 melting season
« Reply #2789 on: July 13, 2017, 04:18:17 AM »
Hyperion....

Those are some frightening images.

Juan C. García

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Re: The 2017 melting season
« Reply #2790 on: July 13, 2017, 04:28:22 AM »
I have appended some rough PIOMAS projections, the first using a 2nd-order polynomial trend line, and the other with a simple linear trend. It is worth having a look at when the various projections intersect the X-axis.

Your first graph shows the tendency of having a new PIOMAS September record (below 2012) on 2017-2018. I hope not, but that is the tendency on the 2nd-order polynomial trend line.

PD: Just to be clear, for me it is badly enough to have a new record on 2017-2018. I agree that a total melt out seems unrealistic, at this time.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

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

Eli81

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Re: The 2017 melting season
« Reply #2791 on: July 13, 2017, 05:37:03 AM »
Big jump in Slater's projection.... Now predicting 5.19m on August 31st.

Did his model just predict the melt season will end in August?  :o

http://cires1.colorado.edu/~aslater/SEAICE/

Ice Shieldz

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Re: The 2017 melting season
« Reply #2792 on: July 13, 2017, 05:50:50 AM »
Decided to do a comparison between Hyperion's Franz Josef Land to pole on worldview 2017 and 2012. For 2012, i had to go a week forward in time (July 21st) to get a clear shot w/o clouds. I ran the same contrast boosting filter on both images. Seems to me 2012 had smaller floes than 2017 - the ice in general seems even more chopped up. Not sure how to quantify the concentration differences?

Click to zoom animation

Tigertown

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Re: The 2017 melting season
« Reply #2793 on: July 13, 2017, 06:14:58 AM »
Barents and Kara 
are warming up.
July 1-13 in 2 day intervals.
CLICK IMAGE

"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

jdallen

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Re: The 2017 melting season
« Reply #2794 on: July 13, 2017, 07:01:42 AM »
A few less clouds today on the Terra-Modis images for the 12th. Nth pole at bottom right corner. Franz-Josef land at top left. Still veil of fog or cloud over most. gives that wavey mottled look. A few spots where there is none and the ocean between the floes stands out nice and dark though.
Its like many other areas.  Large swaths - upwards of 3 million KM2 easily - look to be in a state where they have 5-10 days before they vanish.  Some samples attached.  Pretty much what we see, is isolated early FYI or surviving MYI surrounded by a melange of rapidly disintegrating thin late FYI.

A couple solid whacks and the arctic will be indistinguishable from a bowl of ice cubes.
Successively, from the last couple of days:
Foxe Basin
Western Kara
Barentzs
CAB NE of the ESS
This space for Rent.

jdallen

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Re: The 2017 melting season
« Reply #2795 on: July 13, 2017, 07:03:21 AM »
And one more:  broader view of the western Beaufort to the eastern ESS.
This space for Rent.

Kate

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Re: The 2017 melting season
« Reply #2796 on: July 13, 2017, 07:07:05 AM »
Surface winds atm...looks like an assault from all sides

S.Pansa

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Re: The 2017 melting season
« Reply #2797 on: July 13, 2017, 07:55:01 AM »
Here are the predicted consequences of this all-front assault from Topaz4. Still a bit fare out but for now the forecast does not change that much. The hole ice front along the Russian coast - from ESS to Kara - gets hit this time (especially the Area which Hyperion highlighted so nicely). That confirms, naturally: it is all the Russians fault ;)

My pixel-count-volume-loss-estimate from the 13th to the 21st: ~1.150km³, that is about 140km³ a day, pretty much the same loss-rate as between 1st and 12th. Forecast for the 15th has remained stable at around 7.350-7.400 km³ (all the big ifs still apply).
« Last Edit: July 13, 2017, 09:06:30 AM by S.Pansa »

oren

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Re: The 2017 melting season
« Reply #2798 on: July 13, 2017, 09:04:29 AM »
And one more:  broader view of the western Beaufort to the eastern ESS.
The Beaufort seems very ready to drop a chunk of extent.

seaicesailor

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Re: The 2017 melting season
« Reply #2799 on: July 13, 2017, 10:16:07 AM »
Big jump in Slater's projection.... Now predicting 5.19m on August 31st.

Did his model just predict the melt season will end in August?  :o
Because NSIDC compactness has had a huge rebound and this model is all based on concentration.
Indeed this really smells like a rebound year itself, and with that cyclonic circulation around Greenland.
We'll see, all peripheral seas are for sure compromised, but I suspect the progress will slow down when reaching the CAB. Area got a bit of a mini-cliff before, but now in terms of anomaly it recovered to just over -1 million, see last Wipneus entry on NSIDC data