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ChrisReynolds

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Re: The Slow Transition
« Reply #200 on: October 19, 2014, 07:54:45 AM »
Crandles,

No it doesn't include 2014, it's from a blog post done earlier this year. I will update it.

ChrisReynolds

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Re: The Slow Transition
« Reply #201 on: October 19, 2014, 09:43:56 AM »
With the benefit of 2014 data...

Central Arctic Convergence.



Central Arctic convergence with winter volume decline calculated as described here:
http://dosbat.blogspot.co.uk/2014/04/what-is-future-of-arctic-sea-ice-part-2.html



Note that in both of the above graphs the thin black lines are just lines of best fit, their extrapolation is not backed by physics.


April thickness calculated using the Freezing Degree Days formula (described previously on this thread), using NCEP/NCAR monthly surface air temperature north of 80 degN.



This shows how much further the core of the central Arctic needs to go to drop thermodynamic thickening from open water to well below 2m thick, enabling significant summer open water. Note that this does not account for mechanical deformation making thicker ice in the Central Arctic.

iceman

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Re: The Slow Transition
« Reply #202 on: October 19, 2014, 03:35:13 PM »
....
It is not just important, but *crucial* that you try to work through evidence with a view of trying to prove a different conclusion than the one you *think* is true.  We are hard wired to become attached to our own conclusions to the exclusion of information which disagrees with us.  I strongly encourage you to pursue information which may support conclusions regarding phenomena which are different from your own.  I can assure you, the "Ah Hah!" you can get from that can be better even than finding you are right in the first place; you prove you can change your mind.
....

Good advice, if difficult to adhere to.  Our biases weigh against divergent thinking on an individual basis.  As a community, though, ASIF seems to be pretty effective at it.

viddaloo

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Re: The Slow Transition
« Reply #203 on: October 19, 2014, 04:17:23 PM »
But the winter curve is falling mainly due to loss of multi-year ice (MYI). As can be seen in the plot below the decline in ice over 2m thick in April, the curve of MYI tracks the decline in CT Area.


Wishful thinking, I'm afraid.

Seems to me you are fooled by the fact only the 2+m curve is declining. 2-m is on the up, but why is it on the up? Simply because cells that used to be just above 2 meter are now just below 2 meter.

There's no reason whatsoever the thinning will magically stop at 1.9 meter. (Or if there is, you should expect next year's Nobel Prize for discovering this mystical limit.)
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ChrisReynolds

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Re: The Slow Transition
« Reply #204 on: October 19, 2014, 08:47:51 PM »
Viddaloo,

You said: "Wishful thinking, I'm afraid."

Sounds like wishful thinking.

If you're having trouble grasping it, just tell me what you don't understand and I will try to explain better.

I don't understand your basis for claiming that the rate of melt will not continue to increase until there is no ice left.

This is the second time I've been accused of wishful thinking, at least Great Dying engaged with the argument and although s/he didn't necessarily agree, did seem to consider it.

May be it is time to put my cards on the table, as I nearly did in replying to that post...

Nothing would excite me more than a massive rapid crash to zero, I did think it was going to happen.
http://dosbat.blogspot.co.uk/2013/12/go-on-say-something-outrageous.html
But upon further consideration I changed my mind.
http://dosbat.blogspot.co.uk/2014/04/what-is-future-of-arctic-sea-ice-part-2.html
Once I had changed my mind, I realised that the niggling doubts I had been wrestling with went and stepping back for a broad view of the evidence things made more sense.

So Viddaloo. Why are you now replying to me?

Especially in the sense of once more picking a tiny part of the argument and twisting it to suite your pre-determined agenda? Especially when after being extremely insulting about the scientific community you whined about my robust challenges and I said I'd drop the matter?

You have asked for me to leave you alone, implying I was bullying you. However, note that I have once pointed out the major issue with your claimed 'five year cycle', once and no more out of recognition of the sensitivity of that issue for you. You may also note that in general I leave the whole methane catastrophe alarmism alone, as sceptic of that alarmism I am aware of the sensitivity of the issue for some, and having made my opinion clear in the past I now tend to leave it alone.

Thus I am puzzled that within hours of me saying I would desist from challenging what I see as pseudo-science from you, you cherry pick one part of my argument in a previous post and imply 'magic' when I have previously taken the time and care to explain to you the physical argument. If by accident you stumble upon something of value in elucidating the issue I will reply. But you have clearly already reached your conclusion, you have no interest in my reply, regardless of the time and effort I would put into such a reply.

Therefore I see no point in replying.

viddaloo

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Re: The Slow Transition
« Reply #205 on: October 19, 2014, 09:02:16 PM »
Scientists should feel less and calculate more. Too bad you're not qualified to defend your own theory.
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mark

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Re: The Slow Transition
« Reply #206 on: October 20, 2014, 02:18:35 AM »
viddaloo - I can see how passionate you are about this and I have been reading a lot of your postings on here as well as Chris, ASLR, Wipneus, Jai, jdallen to name a few. I do want to chip in but as most of my postings are going to be conjecture and questions I try to wait for a pause in the traffic. Most people I read on here have a more extreme view of the warming situation than I do - I look to find balancing forcings rather than the opposite, but does that mean I have no place questioning you or others on here. I hope not as true scientists (I believe and due to human nature) will spend the larger amount of time trying to prove their conjecture/hypothesis/theory correct. The really good ones - the ones worth listening to - take criticism on board and then check to see if they might be wrong and there is substance to the argument - thats science in my view.

I have put my self in the line of fire before on this site - I am a warmist but in no way am I an alarmist or CAGW supporter. There is however a flattening of temperatures and now there is a very short term reversal of ice volume. This may be explained by random weather patterns ie weather coincidence, or it might be the start of a balancing effect within the system. It may also be a shift in the oceanic gyres and deep water flows (where my thinking is). There is comment that some heat is being retained within the Arctic deep water circulation, I believe this to be conjecture as the deep water flows are not yet sufficiently researched or measured to come to a conclusion based on data, but my understanding is that these deep waters leave the Arctic via the Greenland/Iceland/Uk gap before they mix and overturn in the subtropical zone, mostly when meeting the saline deep water coming out of the Med, so dont have an immediate effect within the Arctic circulation.

My question on another thread which wasnt answered is, is there evidence that at least some of the recent warming was due to a slowing down of the N Atlantic drift and could this warming of the atmosphere but cooling of the drift (reduced flow) have caused increased salinity and therefore increased flow of NADW? This in turn could mean a prompt return to general warming as the increased outward flow picks up the strength of the inward surface flow.

This would give support to the idea that general trends will remain reasonably smooth but the occasional weather induced extreme event remains possible, I cant remember where as the posts are coming thick and fast but there was a graph of the monthly anomalies with curves fitted. If you were to follow these curves then the curve for the March April May would have it that they would also be ice free only a little time after the July August September curves. Due to the nature of the Arctic and the winter temperatures involved over the CAB, isnt this a little unlikely and calls the fitting of the same order of curves/lines/waves to data like this into question. The curves indicating 'ice free' for the freezing months are bound to be less severe than those of the melt months, so - nice as that looks it doesnt stack up. (IMO )

ChrisReynolds

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Re: The Slow Transition
« Reply #207 on: October 20, 2014, 07:43:28 AM »
Scientists should feel less and calculate more. Too bad you're not qualified to defend your own theory.

Do you know what a victim bully is?

Your last sentence is shown to be a lie by the depth and breadth of postings on this thread.

jdallen

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Re: The Slow Transition
« Reply #208 on: October 20, 2014, 08:31:59 AM »
Wishful thinking, I'm afraid.

Seems to me you are fooled by the fact only the 2+m curve is declining. 2-m is on the up, but why is it on the up? Simply because cells that used to be just above 2 meter are now just below 2 meter.

There's no reason whatsoever the thinning will magically stop at 1.9 meter. (Or if there is, you should expect next year's Nobel Prize for discovering this mystical limit.)

viddaloo...

First off, you and Chris are in agreement with the eventual outcome of the current changes in climate taking place - an ice free arctic.

You are disagreeing over how soon it will take place.

So far, in my view, you haven't established good supporting documentation for the arguments you seem to be making - that the trend implies a crash.  You've presented statistics, but no explanation for what mechanism is driving them.  Further, when presented with reasonable criticism of your conclusion, you've retreated into ad hominem attack.   It doesn't help make what you say any more persuasive to attack Chris.

Put simply, there are two fundamental flaws to your argument at least that Chris and I have presented.  You haven't addressed them.

1) Degree days.  The heat budget of the Arctic at the macro scale is relatively well understood.  While ice has dropped considerably in the peripheral seas, and sub 2M ice has increased dramatically, the last two years have demonstrated succinctly that the system as a whole still has a long way to go before the pack as a whole, or even in majority is driven below the 2M threshold.  The refreeze heat budget needs much higher inputs of energy before the refreeze will be decisively affected.  Chris's graphs are very succinct.  To prove your point, you need to point to where the necessary heat will come from to over come winter losses and reduce the number of freezing degree days.

2) Total system enthalpy.   I've posted qualitatively about this, if not exact numbers, and also spoken to how the variation in volume is reflective of total energy in the system.  While various forcings from AGW have steadily increased the heat in the Arctic to the point that the system season to season is far more volatile with metrics varying wildly, the total heat content is vastly less than that required to decisively overcome winter heat losses that drive the refreeze.   

While heat update in the oceans has skyrocketed in living memory, it has a great deal farther to go before it will support consistent season to season sub 1,000,000KM2 summer minimums.  This is the primary support for the "long tail" in seasonal melt/refreeze that many posters have referenced.  Again, your graphs by themselves are merely numbers on paper.  By themselves, they are no more predictive of the immediate future than similar graphs of stock trends can reliably indicate where price will be in three months.    To do that you need to tear your focus away from the index and look at the fundamentals; heat flow, energy budgets, and the total energy available in the system.   Do that, and you'll have a much better handle on how and when things will change. 
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Laurent

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Re: The Slow Transition
« Reply #209 on: October 20, 2014, 09:29:08 AM »
I think we are missing some data to establish a diagnostic about energy balance. My point of view is that the Atlantic is on his way to pass the Fram Strait. I have no data to affirm that but it would be possible to be more precise if we had just a few ITP buoys (5 mini) along the Fram, so we could have the profile of the flows in and out. The Fram is the key in the arctic, if not already in place, I suggest strongly the scientists to put some buoys there. the samples collected by boats are not enough to me, because I am pretty sure, the flows do vary a lot in time.

ghoti

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Re: The Slow Transition
« Reply #210 on: October 20, 2014, 02:54:33 PM »
This is why I wish someone would drop Argo profiling buoys into the Fram or just north of it. Probably not possible because of the ice interfering with way they work.

ktonine

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Re: The Slow Transition
« Reply #211 on: October 20, 2014, 04:01:51 PM »
viddaloo wrote: "There's no reason whatsoever the thinning will magically stop at 1.9 meter."

No one has claimed this.  You are arguing against a viewpoint of your own invention.  What Chris has shown is that thinning is directly related to warmth; well duh, pretty hard to argue against that. More important, he has shown that the relationship is easily seen by measures we have available to us (Freezing Degree Days).

There are a goodly number of us that *want* to see the arctic melt out sooner rather than later - not because we wish ill on anyone, but because we now see it as inevitable (given lack of action to reduce CO2 emissions) and if it's inevitable we'd like to see how it happens.  Call it morbid curiosity.

That said, we're interested in the science - the actual physics - of how everything fits together.  Chris has taken positions on various arctic processes, and then changed his position when he finds evidence that contradicts or makes his position unlikely.  This is the way we should all approach the subject.

The one paper that confounds many of our beliefs is Recovery mechanisms of Arctic summer sea ice, S. Tietsche, D. Notz, J. H. Jungclaus and J. Marotzke. 26 JAN 2011, DOI: 10.1029/2010GL045698.  If you have not read Tietsche et al and understood it and all of its implications - you should.

The takeaway is, for this discussion, the ice will go when the temperatures are such that the physics dictate it should go.  There are no magical ice fairies directing the ice.  It's simply a matter of energy into the system and how it gets distributed.

Those of us who are not averse to a rapid ice loss event hate Tietsche, but apparently physics does not care whether we 'like' it or not.  Remember, curve fitting is nothing more than a clue - not always a good predictor and definitely of little utility unless a physical basis for extending projected values into the future exists.  2013 and 2014 highlight the fallibility of this, at least in the short-term, for measures of arctic sea-ice.

Note: Schröder andW. M. Connolley's Impact of instantaneous sea ice removal in a coupled general circulation model predated Tietsche et al, but most of us were unfamiliar with it until after we'd read Tietsche.

mark

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Re: The Slow Transition
« Reply #212 on: October 20, 2014, 06:27:09 PM »
Thanks for the 2 references Ktonine, they pretty well answer my questions. Of course the holy grail is why does the Arctic react so extremely to only small rises in temperature especially when there are such strong balancing feedbacks. If CO2 is the catalyst then what is causing the increased effects we are seeing on ice volume. It would seem from the paper by Tietsche that this rapid decline should not happen so easily. I would expect a modeled graph to show only very gradual loss with extreme events followed by rapid recovery to the mean, after all sensitivity is much less in the Antarctic.

jdallen

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Re: The Slow Transition
« Reply #213 on: October 20, 2014, 07:11:09 PM »
I think we are missing some data to establish a diagnostic about energy balance. My point of view is that the Atlantic is on his way to pass the Fram Strait. I have no data to affirm that but it would be possible to be more precise if we had just a few ITP buoys (5 mini) along the Fram, so we could have the profile of the flows in and out. The Fram is the key in the arctic, if not already in place, I suggest strongly the scientists to put some buoys there. the samples collected by boats are not enough to me, because I am pretty sure, the flows do vary a lot in time.

There is quite significant flow all across the North Atlantic/Arctic ocean boundary.  I'd demurre somewhat over the Fram being key, though it is important.  I'd rather put it in these terms; it's not so much that more heat is being added to the Arctic as it is that a slightly lower percentage of heat going there is being lost.

Currents, insolation, GHG forcing, changes in weather all contribute.  The Arctic as a system is undergoing an agonizing transformation of a thousand cuts....
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ktonine

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Re: The Slow Transition
« Reply #214 on: October 20, 2014, 08:12:48 PM »
mark writes: "It would seem from the paper by Tietsche that this rapid decline should not happen so easily."

There is no doubt the models used to generate arctic projections (as cited by the IPCC) are wrong.  Surprise :)

But that shouldn't surprise anyone. What we're really asking is how much do these models deviate from reality?  What both of the above cited papers show is that the ice is going to follow the energy budget.  Remove it all arbitrarily and it "recovers" to where the physics of energy flows dictate. 

Is it possible the models are so wrong that they've missed possible tipping points?  I suppose so, but that avenue appears less likely today than it did two years ago.  After 2012 I was willing to argue that there were factors missing in the models that could lead to rapid ice loss (i.e., seasonally ice-free arctic by 2020).

Still, I don't think it outrageous to believe that two or three consecutive 'warm' years could see what amounts to an ice-free arctic, but that wouldn't last unless there was a permanent change in the weather. The 'permanent change in the weather' is the increase in temperatures due to GHG emissions - chiefly CO2.  But even taking arctic amplification into account this is a relatively gradual process.

As for Antarctica, the arctic and the antarctic are two completely different animals.  Yes, they both follow the same laws of physics, but the specific processes are confounded by completely different geological, topographical, and oceanic conditions.  As has been pointed out many times, one is an ocean surrounded by land - the other land surrounded by ocean. An analogue to the CAB does not exist in Antarctica.  Transport in the CAB is on the order of at most a few years, in the Antarctic it would be measured in centuries or millennia.  There are far more differences between the two polar hemispheres than there are similarities.  Trying to use sea-ice processes in one hemisphere to inform ourselves about sea-ice processes in the other is foolish, except at the most elementary levels I.e., the basic physics -- freezing temperature of sea water, temperature gradients in ice, heat loss vs ice-thickness, etc. are not going to change regardless of hemisphere.



Laurent

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Re: The Slow Transition
« Reply #215 on: October 20, 2014, 08:29:02 PM »
Jdallen :
Yes, of course there is a lot more than the Fram that are changing the Arctic, what I am thinking about it is a process that could accelerate the melting in summer but also in winter. If really the Atlanctic may go forward then it may be that the delay that we are seeing in summer melting may not necessarily delay the date of winter melting...just a thought.

ChrisReynolds

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Re: The Slow Transition
« Reply #216 on: October 20, 2014, 09:12:43 PM »
Laurent,

The main issue with Atlantic Water is that it drops below the colder less saline water to around 100 to 200m depth. A major reason I still think Overland and Wang's prediction of 2030 for earliest virtually ice free state is I suspect that AW may play a greater role with greater ice production in autumn/winter (brine rejection from forming ice) and greater fresh water production from melting water in spring/summer as the pack declines. The other is the 2007 to 2012 summer weather, which may return.

The problem with AW is I haven't yet read of a strong mechanism by which it can come into more active contact with the surface ice. That doesn't mean it can't happpen.

Michael Hauber

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Re: The Slow Transition
« Reply #217 on: October 27, 2014, 08:39:46 AM »
Another point where Arctic ice varies from a thickness governed by thermodynamic thickening of 1st year ice in a single season is the Siberian Ice tongue where there is typically some compaction of 1st year ice and models often show patches of much thicker than 2m ice, although not to the same extent as the multi-year ice north of Canada.  As the freezing season is delayed more and more by warming Autumn conditions this tongue will continue to thin.

Is it a factor big enough to make a difference to the main argument of this thread?  With less thick ice in this region than the multi-year regions perhaps not.  On the other hand it is more vulnerable to complete melt out as happened in 2007 and 2012.  Continued warming may make complete melt out of this region a common event within a 5-10 year period?  Which seems to have implications with 2008 and 2013 (less certain) possibly having enhanced melts due to the after effects of 2007 and 2012.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

ChrisReynolds

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Re: The Slow Transition
« Reply #218 on: October 27, 2014, 09:51:09 PM »
Michael,

I don't think it is. In most summers, this year and 2010 being exceptions, the ESS experiences a high proportion of extent/area melt out. The exceptions seeming to be when there is large export of multi year ice into the region.

Michael Hauber

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Re: The Slow Transition
« Reply #219 on: October 28, 2014, 10:44:46 AM »
hmm about the best I can find in the HYCOM model to demonstrate this effect is in May 2013.  The effect of 1st year ice compaction against the Siberian coast is there, but looks hardly enough to matter.  I could have sworn I'd seen maps in the past with more significant thickness of this ice.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

crandles

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Re: The Slow Transition
« Reply #220 on: October 28, 2014, 11:49:24 AM »
Looking at

and last year


Could 2015 be the last year with significant thick MYI in Beaufort?

mark

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Re: The Slow Transition
« Reply #221 on: October 28, 2014, 03:34:27 PM »
I think that would be a giant leap of conjecture Chris. The amount of MYI anywhere in the Arctic is so dependant on the combined annual total of weather systems and oceanic gyres that increasing/ decreasing amounts of ice seem to develop almost randomly from one year to the next. From that a purely random set of weather patterns may have the Beaufort ice free next year but most likely another area will have a corresponding increase. Even PIOMAS and SIE are susceptible to extreme weather patterns in any year, just look at the 'rebound' values for the last 2 years. Can any of us be sure that the rebound will stop and carry on back downwards this winter. If not then surely we need to wait on at least another 2 years to see whether the trend has altered or just shifted right a bit.

Either way I would think that looking at any of the ice parameters in any one area is unlikely to show agreement with the overall trend.

Dont you just wish we could have 10 years all at once to see whos right!!

crandles

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Re: The Slow Transition
« Reply #222 on: October 28, 2014, 04:33:28 PM »
There is probably plenty of scope for reversal of Beaufort gyre this coming year. Even without that, MYI with thicken from compression by differing amounts each year so there will be variation in what is pushed into Beaufort by the gyre.

Even so it does look remarkable how little thick ice there is off Ellesmere Island compared to last year or 2013 shown above or 2012:


It seems to me that there is a trend towards a narrower band of thick ice along CAA. Thin ice is easier to deform but there is also less mass of ice to do the deforming? If more of the deformed ice that is more than 100 miles from shore gets moved into Beaufort by the gyre there is also possibly less time for significant thickening.

I think this trend has been going on for some time and therefore might be less of a giant leap of conjecture. But there are certainly possibilities that the narrow band off Ellesmere Island this year is just exceptionally small this year and won't be repeated.


This is why I think Chris Reynolds should calculate a minimum possible maximum volume. Something like lower of 2m and April thickness for each cell. If the melt volume is less than this then we clearly need a lot more FYI thinning before we can get close to being ice free.

The current calculation that Chris does saying max volume is about 2m * area is not as persuasive as it could be since some of the area is already below 2m. Doing my suggested calculation above would IMHO allow better feel for how much more FYI thinning is needed versus thick ice thinning.

ChrisReynolds

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Re: The Slow Transition
« Reply #223 on: October 28, 2014, 07:46:23 PM »
Mark, yes it is random, weather plays a strong role. I am not foolish enough to use two cycles to claim a cyclic behaviour.

Michael Hauber, consider the Drift Age Model.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/


2006 large export.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2006_20.gif
Late summer...
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2006_35.gif

Large export - hit by the weather of 2007
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2007_20.gif

Large export - post 2007 rebound year.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2008_20.gif

Small export - post 2007 rebound year.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2009_20.gif

Large export, with a persistent survival of low conc ice in ESS late summer.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2010_20.gif
Late summer...
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2010_35.gif

Small export, tie with 2007 despite weather not being great for melt.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2011_20.gif

Small export, record 2012 minimum.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2012_20.gif

Small export - poor weather for ice loss.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2013_20.gif

Large export, with a persistent survival of low conc ice in ESS late summer.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2014_20.gif
Late summer...
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2014_35.gif

It is not totally convincing at present, the effect seems to have happened in the post 2007 period with substantial reduction of MYI in that sector. A copy of a graph of 30 Aug extent for the ESS is attached. I need more years for enough data to do some maths on it.

PS, from an old blog post of mine:

Again that's week 20.

ChrisReynolds

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Re: The Slow Transition
« Reply #224 on: October 28, 2014, 08:00:19 PM »
This is why I think Chris Reynolds should calculate a minimum possible maximum volume. Something like lower of 2m and April thickness for each cell. If the melt volume is less than this then we clearly need a lot more FYI thinning before we can get close to being ice free.

The current calculation that Chris does saying max volume is about 2m * area is not as persuasive as it could be since some of the area is already below 2m. Doing my suggested calculation above would IMHO allow better feel for how much more FYI thinning is needed versus thick ice thinning.

I'll bear it in mind. But I think the key area is the Central Arctic. The peripheral seas seem to be virtually ice free already in recent years.
http://dosbat.blogspot.co.uk/2014/10/the-fast-transition.html

And as I commented over at Neven's, Zhang seems to think that by the 2020s we'll be in a regime of regular super-2012 summers, with large interannual variability.
http://neven1.typepad.com/blog/2014/10/piomas-october-2014.html?cid=6a0133f03a1e37970b01b8d07a6c1c970c#comment-6a0133f03a1e37970b01b8d07a6c1c970c
First main para and first link of that comment.

Such a situation is pretty much in line with my expectations.


PS - I'm tied up with interviews for new staff for the rest of the week so may not reply for a few days. Sorting the wheat from the chaff and finding all we're getting is chaff.  :(

viddaloo

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Re: The Slow Transition
« Reply #225 on: October 28, 2014, 09:14:21 PM »
LOL, next time you hire, remember to include "no chaff, please" in the ad....
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jdallen

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Re: The Slow Transition
« Reply #226 on: October 29, 2014, 12:46:37 AM »
Responding to Mark, I see Chris has already done a rather thorough job.  I'll just drop in a table of ESS volume numbers (thank again to Chris), which also tend to support what he was saying.


Year    Max      Min      Diff
2000   1667.92   495.90   1172.01
2001   1685.96   896.55   789.41
2002   1413.81   214.31   1199.50
2003   1434.62    59.92   1374.70
2004   1415.26   301.65   1113.61
2005   1419.27    65.63   1353.64
2006   1265.55   224.50   1041.05
2007   1269.34     0.00   1269.34
2008   1126.10    12.09   1114.01
2009   1266.17    24.36   1241.81
2010   1269.29    39.58   1229.71
2011   1175.26    32.38   1142.88
2012   1180.94     0.03   1180.91
2013   1125.56    98.59   1026.97
2014   1132.64   512.16   620.48
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mark

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Re: The Slow Transition
« Reply #227 on: October 29, 2014, 05:47:08 PM »
I could go along with the data there and say that there is a trend of a massive melt year followed by a recovery and then another massive melt year where the maximum volume drops and then steadies for a number of years. But then if you look at the minima - theres the indication of the volatility of the Arctic once the thickness and volume reach the present low values.

I am not suggesting that any way of reading the figures is right or wrong. The trend is still downwards and the likelihood of a total collapse in any one year is getting more and more likely. Its getting very interesting. However the mere presence of such a startling increase in that Minimum value for 2014 (from JDs ESS figures) shows that if weather patterns go the other way there would just as easily be a sustained period of volume building......then what. Chris, Viddaloo et al - you are far more aware of the data than I am and without the tables and graphs I would not be able to comment, so thanks for the replies and info.

ChrisReynolds

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Re: The Slow Transition
« Reply #228 on: October 29, 2014, 07:31:59 PM »
Mark,

I certainly wouldn't go so far as to say we have a crash-recovery cycle here.

2007 did seem to be followed by a recovery drive by thermodynamic growth of sea ice. However after 2012 over winter the growth of sea ice was only enough to bring sea ice volume up to that seen in April 2011 and 2012 (and for that matter April 2014).

For a blog post I have previously plotted the difference between volume on the dates for the graph, and 12 months earlier.

What can be seen is that the 2013 volume increase above 2012 happened from May/June 2013, and ended in February 2014. From this I conclude that there was no autumn/winter thermodynamic rebound, the volume increase was due to weather during the summer.

I've just knocked together a quick graph of 2008 PIOMAS volume minus 2007 PIOMAS volume for comparison.



From this a late winter increase of volume is seen in 2008 over and above the increase of volume in late winter of 2007, that I view as a thermodynamic rebound (e.g. Tietsche effect). This stalls by May before the massive summer losses of volume in 2007 further increase the difference between 2008 and 2007.

So I think the two crashes are followed by entirely different processes that just happen to have the same effect.


Viddaloo, It's really rather frustrating. But I think 'No chaff please' might be considered discriminatory. ;) I'm going to put my feet up now and watch Cockney's vs Zombies. I need something entertaining and undemanding, and free - recorded it off TV last night.

Rubikscube

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Re: The Slow Transition
« Reply #229 on: October 29, 2014, 07:46:51 PM »
Jdallen, are your numbers suggesting that average thickness at minimum was over 5 metres? That I do not believe, nor that ESS volume at min was 5 times higher than 2013.

viddaloo

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Re: The Slow Transition
« Reply #230 on: October 29, 2014, 10:10:27 PM »
So I think the two crashes are followed by entirely different processes that just happen to have the same effect.

Thanks, Chris, that's interesting. I asked this question a week ago in the refreeze thread. If When we get another crash, it will be exciting to see if we get another 2008/2013 following that, or if being so much lower than 2007 and 2012 means it will just unravel and fall to pieces.
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crandles

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Re: The Slow Transition
« Reply #231 on: October 29, 2014, 11:52:55 PM »
Jdallen, are your numbers suggesting that average thickness at minimum was over 5 metres? That I do not believe, nor that ESS volume at min was 5 times higher than 2013.

512 Km^3 divided by area 936000 km^2 per wikipedia which might well be different to the area being used seems to suggest a little over 50cm average thickness rather than 5 metres?

jdallen

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Re: The Slow Transition
« Reply #232 on: October 30, 2014, 09:26:19 AM »
Jdallen, are your numbers suggesting that average thickness at minimum was over 5 metres? That I do not believe, nor that ESS volume at min was 5 times higher than 2013.

512 Km^3 divided by area 936000 km^2 per wikipedia which might well be different to the area being used seems to suggest a little over 50cm average thickness rather than 5 metres?

I think Crandles has it.  I'm confident of the volume numbers.  They were posted not to indicate thickness, but rather to show using the minimums how numbers bottomed out and then popped back up again dramatically in 2014. That tends to support the assertions Chris was making regarding MYI import into the ESS - or other areas - which have suddenly recovered volume after a relatively long period of low end-of-season volume.
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Rubikscube

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Re: The Slow Transition
« Reply #233 on: October 30, 2014, 12:49:12 PM »
512 Km^3 divided by area 936000 km^2 per wikipedia which might well be different to the area being used seems to suggest a little over 50cm average thickness rather than 5 metres?

But hold on a second. This was the minimum, right? According to CT the ESS SIA around minimum was somewhat below 100000^2, and if I'm not completely mistaken 936000 km^2 would be the SIA during winter max. It is otherwise a great piece of information that looks to be perfectly correct, but if you are talking about the same ESS as I am (from CT), then I'm pretty sure the 2014 min volume is a mistake that should be corrected.

EDIT: I did perhaps not make it clear enough in my first post that I was only talking about the 2014 min volume.
« Last Edit: October 30, 2014, 12:59:27 PM by Rubikscube »

mark

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Re: The Slow Transition
« Reply #234 on: October 30, 2014, 01:57:00 PM »
Thanks Chris, I'm certainly not disagreeing - it does show just how unpredictable the Arctic is. I say 'crash' purely on the grounds of 'ifs'. For instance if the 2010/2011 winter maximum had happened in the 2011/2012 winter - what then? Or if the conditions that caused the crash in 2007 happened in 2012, what then, as the loss in 2007 seems to me more severe, saved by there being more ice at the start. Or is it likely that the way the Arctic works prevents this from happening.

I hadnt realised until I started looking at the Arctic in depth how much the ice moves over the year, so reading volumes of any one area is going to be particularly weather sensitive and surely as the volume goes down the speed of movement will go up. Is the ESS and Beaufort being specifically affected by the warm spot in the N Pacific, is it more vulnerable to the developing (if a little weak) El Nino, will an El Nina produce the opposite. Your graphs really only emphasise the difficulties in prediction and a thirst for data that explains anomalies. 

The frustration is not having a reliable set of figures from when this may have happened in the past, it might then be easier to read the feedbacks/forcings. So much work and data but the range is just too small.....frustrating!

crandles

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Re: The Slow Transition
« Reply #235 on: October 30, 2014, 04:06:02 PM »
But hold on a second. This was the minimum, right? According to CT the ESS SIA around minimum was somewhat below 100000^2, and if I'm not completely mistaken 936000 km^2 would be the SIA during winter max.

Sorry about that you are right.

I went looking for the numbers and found these rather different numbers for ESS volume in Chris Reynolds data:
Code: [Select]
Year,        Max______,     Min______,     Diff
1978 2919.36405 1649.89989 1269.46416
1979 3153.66231 2268.77962 884.88269
1980 3796.29684 1621.39826 2174.89858
1981 2956.65407 795.94291 2160.71116
1982 2518.6685 1039.70279 1478.96571
1983 3012.82201 1378.67166 1634.15035
1984 2632.01547 1492.39057 1139.6249
1985 3206.29834 1771.30299 1434.99535
1986 3083.10351 1488.48096 1594.62255
1987 3238.49884 1297.66636 1940.83248
1988 2982.95854 1213.44465 1769.51389
1989 2190.80566 330.04926 1860.7564
1990 1175.56227 184.96378 990.59849
1991 2075.16718 410.52379 1664.64339
1992 2246.95194 349.85569 1897.09625
1993 2108.92558 282.56725 1826.35833
1994 2274.42559 818.88331 1455.54228
1995 2334.46478 455.17749 1879.28729
1996 2090.20179 1033.12642 1057.07536
1997 2257.90087 613.58858 1644.31229
1998 2733.05596 1174.69948 1558.35649
1999 2989.74188 1042.59804 1947.14384
2000 2335.98801 613.92605 1722.06196
2001 2698.42151 953.7547 1744.66681
2002 1862.5505 262.51785 1600.03265
2003 1647.68722 66.80174 1580.88549
2004 2315.30909 394.71429 1920.5948
2005 1961.64412 129.87297 1831.77115
2006 2340.02033 291.83155 2048.18879
2007 1868.94052 0.31506__ 1868.62546
2008 1918.64205 47.29779 1871.34426
2009 1795.21504 33.73221 1761.48283
2010 2470.29866 76.49001 2393.80864
2011 1628.89483 48.36942 1580.52541
2012 2032.29842 2.62944__ 2029.66898
2013 2058.43549 128.54453 1929.89096
2014 1568.46612 74.89849 1493.56764

Suspect the 1990 numbers are wrong for some reason.
« Last Edit: October 30, 2014, 04:22:29 PM by crandles »

crandles

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Re: The Slow Transition
« Reply #236 on: October 30, 2014, 04:31:09 PM »
If these are the numbers, then the max volume has certainly levelled off between 1.6 and 2.5m thick for quite a while now.

This direction has land such that there isn't a taper off with thickness considerably less than 2m that some directions will have.

(Forgot to say earlier that Max is May and Min is Sept every year, it is possible than in some years these weren't max and min months as I haven't checked.)

mark

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Re: The Slow Transition
« Reply #237 on: October 30, 2014, 05:35:46 PM »
looking through the ref given by Chris - at all the week36 (as good a point as any) charts going back to 1984, I can see how bad it has got. However as far as the Beaufort and ESS are concerned these had large amounts of MYI in the 80s and this trend, even though decreasing, was fairly steady until 2007 when the ice nearly completely disappeared from these areas. That continued through to 2012 but now there seems to be a return to more ice in these areas since the recovery from 2012. The confusing factor is that there seems to be a very strong oceanic gyre in the Beaufort at the moment - perhaps that is critical in opening up ice free areas to lose more heat and to build up thicker ice where it impacts into the Canadian Archipelego - it would also put pressure on the ice pack to move into Fram area where there is more ice now than back in the 80s. I cant find the right information to see if this Gyre reverses into a predominantly clockwise direction when the ice nearly disappeared there in 2007 and 2012. If so what causes it, is it just surface flow driven by cyclonic/anticyclonic weather influences or more by the deeper water flows.

jdallen

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Re: The Slow Transition
« Reply #238 on: October 30, 2014, 06:13:03 PM »
But hold on a second. This was the minimum, right? According to CT the ESS SIA around minimum was somewhat below 100000^2, and if I'm not completely mistaken 936000 km^2 would be the SIA during winter max.

Sorry about that you are right.

I went looking for the numbers and found these rather different numbers for ESS volume in Chris Reynolds data:
Code: [Select]
Year,        Max______,     Min______,     Diff
1978 2919.36405 1649.89989 1269.46416
1979 3153.66231 2268.77962 884.88269
1980 3796.29684 1621.39826 2174.89858
1981 2956.65407 795.94291 2160.71116
1982 2518.6685 1039.70279 1478.96571
1983 3012.82201 1378.67166 1634.15035
1984 2632.01547 1492.39057 1139.6249
1985 3206.29834 1771.30299 1434.99535
1986 3083.10351 1488.48096 1594.62255
1987 3238.49884 1297.66636 1940.83248
1988 2982.95854 1213.44465 1769.51389
1989 2190.80566 330.04926 1860.7564
1990 1175.56227 184.96378 990.59849
1991 2075.16718 410.52379 1664.64339
1992 2246.95194 349.85569 1897.09625
1993 2108.92558 282.56725 1826.35833
1994 2274.42559 818.88331 1455.54228
1995 2334.46478 455.17749 1879.28729
1996 2090.20179 1033.12642 1057.07536
1997 2257.90087 613.58858 1644.31229
1998 2733.05596 1174.69948 1558.35649
1999 2989.74188 1042.59804 1947.14384
2000 2335.98801 613.92605 1722.06196
2001 2698.42151 953.7547 1744.66681
2002 1862.5505 262.51785 1600.03265
2003 1647.68722 66.80174 1580.88549
2004 2315.30909 394.71429 1920.5948
2005 1961.64412 129.87297 1831.77115
2006 2340.02033 291.83155 2048.18879
2007 1868.94052 0.31506__ 1868.62546
2008 1918.64205 47.29779 1871.34426
2009 1795.21504 33.73221 1761.48283
2010 2470.29866 76.49001 2393.80864
2011 1628.89483 48.36942 1580.52541
2012 2032.29842 2.62944__ 2029.66898
2013 2058.43549 128.54453 1929.89096
2014 1568.46612 74.89849 1493.56764

Suspect the 1990 numbers are wrong for some reason.

Hmmm. Wonder if I messed up somehow... I was. Graphing using Chris' data. Perhaps I transformed something incorrectly.
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crandles

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Rubikscube

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Re: The Slow Transition
« Reply #240 on: October 30, 2014, 09:59:50 PM »
Thank you very much for correcting crandles, I didn't realise that all the data was wrong (even though captain hindsigth says we should have noticed ;)).

crandles

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Re: The Slow Transition
« Reply #241 on: October 31, 2014, 01:05:08 PM »
Thank you Chris Reynolds for making the data available. Here are some regions:

BarentsVolume by crandles2011, on Flickr

LaptevVolume by crandles2011, on Flickr

BeaufortVolume by crandles2011, on Flickr

ChukchiVolume by crandles2011, on Flickr


To me these seem to show the maximum volume continues to decline after the sea becomes seasonally ice free. Therefore the melt in these regions is declining. However we know that the total melt is increasing. Thus it seems reasonable to suspect that as the maximum volumes in seasonally ice free seas decline, this is likely having an effect of increasing melt in the central arctic basin - probably in the same sector give or take a bit of movement due to gyre/transpolar currents.


crandles

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Re: The Slow Transition
« Reply #242 on: October 31, 2014, 01:39:08 PM »
3 more if anyone interested in seeing them:

KaraVolume by crandles2011, on Flickr

EastSiberianVolume by crandles2011, on Flickr

CentralABVolume by crandles2011, on Flickr

cesium62

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Re: The Slow Transition
« Reply #243 on: November 03, 2014, 05:14:32 AM »
Chris:  Did you see

"
"If Arctic pack ice is continually opening and closing during the Arctic winter on a widespread basis, it could significantly increase the rate of Arctic ice production and therefore increase the total amount of ice in the Arctic," Kwok said. "A simple simulation of this ice production process shows that it can account for an equivalent of 10 centimeters (4 inches) of ice thickness over six months of winter. That's approximately 20 percent of the base growth of thick ice during the central Arctic winter."
"

http://www.nasa.gov/home/hqnews/2004/apr/HQ_04132_arctic_sea_ice.html

That's from 2004, so apologies if that's a well known reference already...

ChrisReynolds

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Re: The Slow Transition
« Reply #244 on: November 03, 2014, 08:11:55 PM »
I am not deliberately ignoring. Laptop crashed and am relying on my smartphone, which is far from ideal. Got time off tomorrow to either fix the laptop or buy a new one. Hope to be back to normal tomorrow.

jai mitchell

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Re: The Slow Transition
« Reply #245 on: November 04, 2014, 05:11:48 PM »
Posted on another thread but seemed very relevant here:  This has strong implications for Tietsche et. al. 2011 and the mechanisms for recovery in those models.

http://www.pnas.org/content/early/2014/10/29/1413640111

Far-infrared surface emissivity and climate
We also describe a previously unidentified mechanism that amplifies high-latitude and high-altitude warming in finding significantly lower values of far-IR emissivity for ocean and desert surfaces than for sea ice and snow. This leads to a decrease in surface emission at far-IR wavelengths, reduced cooling to space, and warmer radiative surface temperatures.

Quote
In the Arctic, the simulations found that open oceans hold more far-infrared energy than sea ice, resulting in warmer oceans, melting sea ice, and a 2-degree Celsius increase in the polar climate after only a 25-year run.

This could help explain why polar warming is most pronounced during the three-month winter when there is no sun. It also complements a process in which darker oceans absorb more solar energy than sea ice.


 Read more at: http://phys.org/news/2014-11-berkeley-lab-scientists-driver-arctic.html
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ChrisReynolds

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Re: The Slow Transition
« Reply #246 on: November 07, 2014, 08:14:43 AM »
Viddaloo,

When we get another crash, and you're right it is a 'when', we will see stronger winter growth than in the years before, like 2007 and 2012. But I reckon the process is now such that we will see more of a post 2012 behaviour than post 2007. The ice is chasing a receding equilibrium, in 2007 it went ahead of the local equilibrium (I suspect), although now it has reached a bumping along the bottom state (I suspect) for the reasons stated in this thread.

Mark,

2012 was not a year of massive volume loss, like 2010 and 2007. In 2007 the volume loss was 2.6k km^3 between Sept 2006 and 2007. If that loss had happened based on the Sept 2011 volume of 4.5k km^3 then September 2012 volume would have been 1.9k km^3. I can give details if needed, but there is a relationship between extent in Sept and volume in Sept, using this relationship extent would have been around 3M km^2 for that volume, although the error bounds on that are so large you might as well say the extent would have been lower than it actually was in 2012.

The Beaufort Gyre is typically clockwise because it is driven by a semi-permanent high over that region. In the winter before 2007 there was a strong gyre and (IIRC) a large export from the central Arctic. Winter Fram export is higher than summer, so the presence of ice in Fram now tells us nothing about the prospects for fram export this winter. However a strong high pressure over the Arctic (negative AO) should encourage a stronger Beaufort Gyre and stronger Fram export. So the best bet for getting rid of some of the thick ice gained over the last two years is a repeat of the Warm Arctic Cold continents pattern like in winter 2009/2010. Snow Advance over Eurasia seems to have been strong this October which mas tip the balance in favour over such a winter this year.

viddaloo

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Re: The Slow Transition
« Reply #247 on: November 07, 2014, 08:48:06 AM »
Viddaloo,

When we get another crash, and you're right it is a 'when', we will see stronger winter growth than in the years before, like 2007 and 2012. But I reckon the process is now such that we will see more of a post 2012 behaviour than post 2007. The ice is chasing a receding equilibrium, in 2007 it went ahead of the local equilibrium (I suspect), although now it has reached a bumping along the bottom state (I suspect) for the reasons stated in this thread.

You may be right, but first let me say I sympathize with you for the hardware trouble. I lost a laptop earlier this autumn, but were lucky enough to have very recent backups, thanks mainly to inspiration from this forum.

You know the ice much better than me, but from my two months of studying the volume data, I now suspect the next 'crash' (record decline) to be much more severe than 07 and 12. As much as I would love to cling on to my '5–Year Cycle' hypothesis, I fear the game will have changed, mainly due to tipping points to do with ocean enthalpy and thus much lower Yearly Average Volumes. Then we may see a crash and a deterioration of the remaining ice in the years that follow.

Again, I stress that I know only the statistical volume data, and my physical model is only in my head and very sketchy. My 'battle plan' is to explore the subject from that angle and see where it takes me; hopefully it can shed new light on the subject for people who know a lot more than me about the ice and the Arctic. This forum seems to be full of them, and I am humble to be in such good company! :)
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ChrisReynolds

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Re: The Slow Transition
« Reply #248 on: November 07, 2014, 09:20:04 AM »
Rubikscube,

You cannot directly compare PIOMAS volume and any metric of area/extent to get an accurate thickness calclation, this is particularly the case in summer.

Crandles has linked to the source of my regional breakdowns which include thickness.
http://dosbat.blogspot.co.uk/2013/12/regional-piomas-volume-data.html

Take September 2014. PIOMAS volume for the ESS was 74.9km^3. Thickness was 0.34m, or 0.00034km. So the area was 0.22M km^2, that's a monthly average. Cryosphere Today (CT Area) suggests that area was rather lower than that. (between 0.1 and 0.2M km^2)

Looking at CT Area and PIOMAS shows that the two are not directly comparable.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=01&fy=2014&sm=09&sd=30&sy=2014
My plot of PIOMAS thickness attached.

Note that when calculating thickness I follow the convention of Dr Zhang, that gridded thickness under 15cm is discounted. So that removes a lot of the thinnest ice in the attched plot. However the areas are not the same and the only way to calculate thickness is to use raw gridded data.

Crandles,

There is no error in 1990, in that year PIOMAS shows a largescale retreat from the Siberian coast causing volume to plummet, compare the volume in May (max volume) to other years.

Jai Mitchell,

But there is still a good relationship (R2 ~ 0.5) between either cumulative open water over the summer or end of summer open water (31 August) and the near surface temperature over the Arctic Ocean in October. In other words, the heat gained in the summer is being vented to the atmosphere. Radiation is actually a minor player, by far the greatest contributors are sensible and latent heat fluxes (Tietsche et al fig 3), furthermore your reference states that ice is a good emitter of IR. And as I argue in this blog post heat flux through the ice has increased suggesting a role in winter warming after ice has formed.
http://dosbat.blogspot.co.uk/2013/10/winter-warming-and-sea-ice-thinning.html

So the impact on the conclusions of Tietsche et al are minimal.


PS Viddaloo - posted while I was writing the above. In the end the ice/ocean system will be the ultimate authority on what will happen, all we can do is try to educate our guesses.

The PC was fixed a day ago. As I was doing that, the TV's fault, which had for much of the summer corrected on application of a good slap, became permanent. So I had every module of the TV removed and spread across the floor last night, after which I reassembled.

Slapping appliances and getting them working has a jokey terminology in engineering, it's called perussive maintenance. It almost always indicates poor internal connectors and the cure is a total dismantle and reassembly. There's a tip that might save you rather a lot of money in the future (but unplug the item first!).  ;D

ChrisReynolds

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Re: The Slow Transition
« Reply #249 on: December 02, 2014, 07:27:38 PM »
Woo Hooo!!!

With the help of a pdf of lecture notes...
http://nit.colorado.edu/atoc5560/week13.pdf

I am now able to calculate insolation (ignoring the variation in sun-earth distance and Milankovitch type cycles) for any latitude on any day of the year.  ;D 8) ;D

Here's the Excel equation.

=($O$5/PI())*(ACOS(IF(ABS(-1*TAN(DR$7)*TAN($N10))>1,SIGN(-1*TAN(AT$7)*TAN($N10)),-1*TAN(AT$7)*TAN($N10)))*SIN($N10)*SIN(AT$7)+SIN(ACOS(IF(ABS(-1*TAN(DR$7)*TAN($N10))>1,SIGN(-1*TAN(AT$7)*TAN($N10)),-1*TAN(AT$7)*TAN($N10))))*COS($N10)*COS(AT$7))

Horrible isn't it?  ;)