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JMP

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Re: Home brew AMSR2 extent & area calculation
« Reply #2800 on: October 31, 2016, 06:42:49 AM »
The lack of increase is so remarkable I cannot but comment - apologies - and also if you click on the Antarctic - extent there is much lower than usual too.     To me the Arctic extent, by itself alone, appears disturbing.  The antarctic change, though if-of lesser import, being ice apples vs ice oranges, still only seems to add to this.   So... is this not remarkably unprecedented?    Someone (with better understanding) put this in context, please. 
   
     https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: October 31, 2016, 06:57:52 AM by JMP »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2801 on: October 31, 2016, 08:24:32 AM »
Far (no exaggeration here)  below anything else (in my limited set of years) at this time of year:

Update 20161030.

Extent: -26.6 (-1456k vs 2015, -1847k vs 2014, -1786k vs 2013, -716k vs 2012)
Area: -34.9 (-1415k vs 2015, -1782k vs 2014, -1807k vs 2013, -741k vs 2012)

(the 2012 compare is with UniH SSMIS 12.5km, which should be close to the real AMSR2 data when available)

Today's drops in area and extent are partly (CAA dropped fast too) caused by the continuing battle on the Wrangel/Chukchi arms:

Pmt111500

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Re: Home brew AMSR2 extent & area calculation
« Reply #2802 on: October 31, 2016, 08:49:13 AM »
  So... is this not remarkably unprecedented?    Someone (with better understanding) put this in context, please. 
Attempting to give some context though i guess there are several people more qualified than me on the forum to do this...

Well, at least if you search for well-documented records, i'm afraid this is rather hard to put in any context. There is quite a little, after all, that we know of the transition from younger dryas to Holocene maximum. I would possibly suggest the normal seesaw between antrctic and arctic waters is disturbed by the extra ir made by increased water vapour thus staedy-state models arent too good for this.

But maybe you wanted a context more close in history, id possibly suggest checking antarctic numbers in 2006.

But yes, could well be unprecedented in historical times (after 4004bc). This sort of ocean behavior cannot though explain the flood of Noah, if we assume it to have been taken place at the traditional date, to tke a fundamentalist context.

(all this is though rather much assuming the warm north Pacific is not a recurrent phenomenon, but reserved only to the transitional periods of climate system. But there is some science on mega-drougths in North America and the Pacific warmth has brrn tied to it by some researchers. Could well be we're at the start of such a period lasting several decades.)
« Last Edit: October 31, 2016, 10:17:42 AM by Pmt111500 »
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johnm33

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Re: Home brew AMSR2 extent & area calculation
« Reply #2803 on: October 31, 2016, 11:37:05 AM »
"Wrangel/Chukchi arms" persistent wind and 2.5m waves https://www.windytv.com/?waves,85.706,-61.056,4

Tor Bejnar

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Re: Home brew AMSR2 extent & area calculation
« Reply #2804 on: October 31, 2016, 01:45:33 PM »
I like efforts like Etienne's that show aspects of the larger context (in this case, using 12-month running averages).  I find it interesting that the best-fit curve shows, basically, a steady trend and not an exponential one.  As a pessimist, I expect the bottom to drop off in the next 5-10 years, and 2007 (on his de-trended graph) will no longer look extreme.

Bad news: deniers of the significance of climate change would extrapolate this graph to show that a perennial ice-free Arctic won't occur for 150 years or so!

Etienne's graph shows more detail, but is otherwise like the middle graph fromClimate4You:

Explanation by Climate4You: Graphs showing monthly Antarctic, Arctic and global sea ice extent since November 1978. The area covered by sea ice is defined as having at least 15% sea ice cover. Thin blue lines show monthly values, and thick blue lines show the simple running 13 month average. The red lines show the 1979-2014 average. Data kindly provided by the   National Snow and Ice Data Center (NSIDC). Last month shown: September 2016. Latest figure update: 4 October 2016.

Hello,

I updated my artic sea ice average graph.



I calculated that we are now at 10.33E6 km^2, on the lowest sea ice extent yearly average since January 1990, which probably means since a much longer time. For January 2013 (average 2012), I have 10.38E6; for October 2011 (averange 2011 melting season) 10.44E6; and for November 2007 (average 2007 melting season) 10.46E6.

Best regards,
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etienne

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Re: Home brew AMSR2 extent & area calculation
« Reply #2805 on: October 31, 2016, 05:03:01 PM »
Hello,

Thank you for quoting me.

About your comment :

Bad news: deniers of the significance of climate change would extrapolate this graph to show that a perennial ice-free Arctic won't occur for 150 years or so!

I would like to add that trends only give information on the past, but don't provide any clue for the future if stability is lost. Stock exchange are a good example of this, there were many surprised people end October 1929.

Furthermore, trends could be anything, the strait line seems to fit. If you zoom enough on the side of a circle, you also see a strait line. Our data only cover a very short time compared to the speed of evolution of our climatic system.

What worries me is that we are breaking records without being much out of the trend, everybody seemed to agree that 2016 had poor melting conditions, but the minimum is lower than for 2007. What will happen next time we have 2007 melting conditions ?

I also see a risk that economical slowdown, if we send less dust in the atmosphere, could speed the heating of the planet. You only can change yourself, not the others.

Best regards,

Etienne

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Re: Home brew AMSR2 extent & area calculation
« Reply #2806 on: October 31, 2016, 06:38:59 PM »
I don't know if this situation will cause a huge lose of oceanic heat, and a rebound year in 2017, or a very thin ice cover that melts out to record levels next year.
As far as I know it's totally unprecedented, dating back at least 6k yrs to when the Canadian ice shelves were last gone.
The north of 80d temperature is ~10c too high & water temperatures are ridiculous.
Terry

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Re: Home brew AMSR2 extent & area calculation
« Reply #2807 on: October 31, 2016, 09:56:29 PM »
I don't know if this situation will cause a huge lose of oceanic heat, and a rebound year in 2017, or a very thin ice cover that melts out to record levels next year.
As far as I know it's totally unprecedented, dating back at least 6k yrs to when the Canadian ice shelves were last gone.
The north of 80d temperature is ~10c too high & water temperatures are ridiculous.
Terry
I think that's the $64 question Terry.  How much of that excess heat we see now is coming out of the water, and how much is being imported from elsewhere?

My sense is right now mostly elsewhere, as if it were coming out of the ocean, we'd see notable drops in SST's.  That's not happening, from what I can tell.

The other sense I have is, the storms in particular on the Pacific side have pretty well mangled the distribution of heat and salinity in the water column.  That would tend to undermine the typical thermal isolation of the top 100M or so of the column.  If we can get some data, I'd be very UNsurprised to see confirmation of that.

There's *always* been enough heat in the Arctic to keep it ice free year round.  What hasn't been present, is a mechanism to distribute that heat so the ice doesn't form.  We may be seeing the start of the mechanism arising that eventually will do that.
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bbr2314

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Re: Home brew AMSR2 extent & area calculation
« Reply #2808 on: October 31, 2016, 10:20:18 PM »
I don't know if this situation will cause a huge lose of oceanic heat, and a rebound year in 2017, or a very thin ice cover that melts out to record levels next year.
As far as I know it's totally unprecedented, dating back at least 6k yrs to when the Canadian ice shelves were last gone.
The north of 80d temperature is ~10c too high & water temperatures are ridiculous.
Terry
I think that's the $64 question Terry.  How much of that excess heat we see now is coming out of the water, and how much is being imported from elsewhere?

My sense is right now mostly elsewhere, as if it were coming out of the ocean, we'd see notable drops in SST's.  That's not happening, from what I can tell.

The other sense I have is, the storms in particular on the Pacific side have pretty well mangled the distribution of heat and salinity in the water column.  That would tend to undermine the typical thermal isolation of the top 100M or so of the column.  If we can get some data, I'd be very UNsurprised to see confirmation of that.

There's *always* been enough heat in the Arctic to keep it ice free year round.  What hasn't been present, is a mechanism to distribute that heat so the ice doesn't form.  We may be seeing the start of the mechanism arising that eventually will do that.

I agree with your last graf. I think the drop in sea ice has been compounded by the very rapid snowcover growth along peripheral landmasses, which created an additional layer of gradient (cold sea ice, warm arctic ocean/peripheral seas on edge, very cold landmasses). This may be serving to exacerbate the current condition, with remaining open water now acting as a repository for lower-latitude heat that continues to be drawn into the Arctic on both the Pac and ATL sides.

That means that as the sea ice decreases and as snowcover increases, the relationship is reinforced over time, and we may indeed have now crossed a tipping point where heat continues to be drawn into the Arctic all year long...

Okono

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Re: Home brew AMSR2 extent & area calculation
« Reply #2809 on: November 01, 2016, 12:29:28 AM »
I think that's the $64 question Terry.  How much of that excess heat we see now is coming out of the water, and how much is being imported from elsewhere?

My sense is right now mostly elsewhere, as if it were coming out of the ocean, we'd see notable drops in SST's.  That's not happening, from what I can tell.

There's *always* been enough heat in the Arctic to keep it ice free year round.  What hasn't been present, is a mechanism to distribute that heat so the ice doesn't form.  We may be seeing the start of the mechanism arising that eventually will do that.

These statements should have been patently obvious to me, but they weren't, so this was actually crucial insight.

I'll add one question: is transport of heat to the poles net neutral, positive, or negative for planetary energy balance?

Since black-body radiation varies by the fourth power of temperature, it would seem that a more uniform distribution of heat -- hotter poles using energy taken from elsewhere -- would actually reduce the total radiation exiting the planet, no?

If so, and it's of meaningful scale, then we're not even losing heat on net from this redistribution.  We're retaining more.
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oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2810 on: November 01, 2016, 12:55:30 AM »
Since black-body radiation varies by the fourth power of temperature, it would seem that a more uniform distribution of heat -- hotter poles using energy taken from elsewhere -- would actually reduce the total radiation exiting the planet, no?
I believe it's the temperature difference between the black body and its surroundings that matters, and since the dark arctic sky is extremely cold,  energy is lost and not gained by the redistribution from tropics to arctic. Not sure if the lost energy makes any significantbdifference or not though

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Re: Home brew AMSR2 extent & area calculation
« Reply #2811 on: November 01, 2016, 04:40:05 AM »
Since black-body radiation varies by the fourth power of temperature, it would seem that a more uniform distribution of heat -- hotter poles using energy taken from elsewhere -- would actually reduce the total radiation exiting the planet, no?
I believe it's the temperature difference between the black body and its surroundings that matters, and since the dark arctic sky is extremely cold,  energy is lost and not gained by the redistribution from tropics to arctic. Not sure if the lost energy makes any significantbdifference or not though
The problem is defined by this metaphor:  More water, same pipe.

Blackbody radiation out of the top of the atmosphere is a direct function of temperature.  There's no convection, no conduction - the loss is all direct emission of IR and longer wavelengths.  It will only vary by a few percent, based on temperature at the top of the atmosphere. It won't increase enough to shed extra heat that's been getting passed north and south from mid-latitudes.

By extension, the rate of flow out of the atmosphere won't increase until we have sufficient pressure - increase in temperature - to force more radiation out of the top of the atmosphere.

Heat built up at lower latitudes suffers the same problem - too much water, too little pipe. The heat there *does* have both a convective and conductive outlet - flow to the Arctic and Antarctic.  Thus Arctic amplification by way of heat inflows into high latitudes we see currently.  The extra heat we see in the Arctic has never originated there. Its all coming from somewhere else. It's heat that built up in those places and because of our problem - too much water, not enough pipe - and it finds other places to go, as well as increase the net enthalpy of the system.

In some ways its entropy at work - concentrations attempting to distribute themselves.  In this case, that redistribution of heat is changing the behavior of the system writ large.  It won't settle down until and unless heat distribution has dispersed it sufficiently even things out.
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Okono

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Re: Home brew AMSR2 extent & area calculation
« Reply #2812 on: November 01, 2016, 04:54:02 AM »
I believe it's the temperature difference between the black body and its surroundings that matters, and since the dark arctic sky is extremely cold

The first half of this is right and it gives us the right thought framework: just like jdallen's point that there has always been plenty of energy in the system.  Think insulation.

https://en.wikipedia.org/wiki/Boltzmann_equation

The rest, I dunno.  I would be surprised if the stratosphere above the Arctic were a dramatically worse insulator than that over the rest of the planet, and it's all 2.7°K eventually.  If the atmosphere is sufficiently well-mixed, it still leaves the notorious variable: clouds.

Observations give us two solid facts: the planet loses vastly more energy from the equatorial regions than polar regions and the loss from the polar regions is so small that we're probably obsessing over a largely irrelevant variable.  I'm sure someone has already ballparked the impact of intra-planetary heat distribution on total OLR well, but I can't find it.

http://www.esrl.noaa.gov/psd/map/clim/olr.shtml

You've both got me thinking in terms of what polar amplification means for heat transfer rates.  Since polar amplification is by definition the poles warming faster than the equatorial regions, it should slow down further poleward transfer of energy, and that's probably the more important gradient.

But, I dunno.  This one's chewy.
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DoomInTheUK

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Re: Home brew AMSR2 extent & area calculation
« Reply #2813 on: November 01, 2016, 11:07:51 AM »
It could be me, but I get the feeling that the warm waters are keeping the freeze at bay just long enough for the next storm to roll in and mix the waters up again.
It's probably too early to indicate anything much as a few weeks of really good freezing weather would get us back on track. The only problem is there doesn't seem to be any freezy weather ready to pounce.
I keep telling myself it's still early in the freeze season, but we're almost a third of the way through it.

If ever there was an example of global weirding, this is it.

Archimid

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Re: Home brew AMSR2 extent & area calculation
« Reply #2814 on: November 01, 2016, 12:33:48 PM »
Full Definition of doomsday
1:  a day of final judgment
2:  a time of catastrophic destruction and death

I have not read anyone talking about religion or judgement, so the first definition of doomsday does not apply. However the second definition is appropriate for what we are seeing. The lack of ice creation during winter, presents a real chance for catastrophic destruction come the melting season. I don't understand why some people deride forum members who are discussing possible catastrophic scenarios.  I think there is extraordinary evidence that support the extraordinary claim that there is a very real possibility for doomsday scenario.

Talking about this is hard enough. Many times I find myself deleting what I wrote because the thoughts of the possible ramifications of an ice free arctic are very uncomfortable. Talking about a very real doomsday is hard enough as it is. We really don't need people making fun of you on top of it. That discourages analysis of dangerous but possible paths, increasing the risk for all.

 
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DoomInTheUK

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Re: Home brew AMSR2 extent & area calculation
« Reply #2815 on: November 01, 2016, 01:11:24 PM »
Maybe we need a new thread (in Consequences?) on the potential threats caused by the loss/reduction in Arctic sea ice.

http://forum.arctic-sea-ice.net/index.php/topic,1768.0.html
« Last Edit: November 01, 2016, 01:40:24 PM by DoomInTheUK »

marcel_g

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Re: Home brew AMSR2 extent & area calculation
« Reply #2816 on: November 01, 2016, 04:01:30 PM »
Well said Archimid

plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #2817 on: November 01, 2016, 10:38:33 PM »
The point is that a doomsday discussion needs extremely good scientific backup, otherwise it becomes fearmongering paired with catastrophe voyeurism. It is not doomsday if our coastal cities get flooded. It is simply _very_ expensive. It is also not doomsday if we wipe out the polar bears - it is sad, very sad. And if WACCy situations like the current one make it cold and snowy in Europe from mid November, it is a mere inconvenience, but not doomsday. I have taken on many climate deniers, and you certainly don't win by spelling doom.

@Okono: Fully agreed, l have always been missing that in discussions. One of the reasons why arctic amplification works so well. I don't think I fully grasp your argument about it slowing the heat transfer rates, though. If we assume a more meridional circulation caused by a reduced temperature gradient, I would think that there the amplification actually increases heat transfer. Would also explain why it tends to be on the upper end of what one might naively expect from pure albedo feedback.


Okono

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Re: Home brew AMSR2 extent & area calculation
« Reply #2818 on: November 02, 2016, 01:02:56 AM »
The point is that a doomsday discussion needs extremely good scientific backup, otherwise it becomes fearmongering paired with catastrophe voyeurism.

+1

Sorry again for dragging this off into the OT swamp, but I think it's a useful swamp.  Brackish Miami, if you will. :p  I get frustrated seeing us in petty monetary compensation negotiations over these things when it is, in my esteem, the least of our worry.

I hate to infer from that what £ead€r$h¥p really cares about, but honestly, if I were in their shoes, I would probably have given up and entered hustler mode too.

@Okono: I don't think I fully grasp your argument about it slowing the heat transfer rates, though. If we assume a more meridional circulation caused by a reduced temperature gradient, I would think that there the amplification actually increases heat transfer.

Totally simplistic.  Just that the heat transfer rate depends on the temperature difference, just like everything else.  If the temperatures converge, then the heat transport should slow in response.

As you point out, the Earth is a "slightly" more complicated system than that.  I wouldn't be stunned if a law based on Brownian motion(Boltzmann) is dominated by another process entirely(circulation patterns) in such a system.

Of all the things that we can model, getting an order of magnitude estimate on something we can observe today and presuming that relationship holds indefinitely is...

... I guess exactly like the rest of climate modeling.  Cripes.

edit: better phrasing
« Last Edit: November 02, 2016, 02:17:23 AM by Okono »
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Archimid

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Re: Home brew AMSR2 extent & area calculation
« Reply #2819 on: November 02, 2016, 01:09:28 AM »
Sorry for posting this very off topic rant in this wonderful thread, but I feel it must be done. It will be my last post on this thread about this. This thread is one of those threads that make me giddy every time I see there is a new post because I know it's going to be a good one.

The evidence clearly indicates that dramatic change is happening and it's accelerating. Models say that it will accelerate even more. Mass extinctions is the expected result of sudden climate change. The rate of change in the arctic is clearly exceeding most "consensus" expectations.  Mass extinction is the expected result of the destruction of the arctic. Death and destruction. That is literally the definition of  doomsday.

 A flooded coastal city is doomsday from the point of view of the inhabitants of the city. From the point of view of the Polar Bears, it will also be doomsday. (I think their doomsday started sometime ago, it will just be the end).

Done with this. Sorry again for posting this here.
 
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Ninebelowzero

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Re: Home brew AMSR2 extent & area calculation
« Reply #2820 on: November 02, 2016, 01:14:44 AM »
We need a Crysofear sub forum in the off topic zone perhps?  8)

Glenn Tamblyn

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Re: Home brew AMSR2 extent & area calculation
« Reply #2821 on: November 02, 2016, 09:26:09 AM »
DITU

"It's probably too early to indicate anything much as a few weeks of really good freezing weather would get us back on track. "

It might, probably will get us back on track in terms of area/extent. Back on track in terms volume? Not so sure and likely far more significant.

DoomInTheUK

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Re: Home brew AMSR2 extent & area calculation
« Reply #2822 on: November 02, 2016, 09:39:05 AM »
I agree that volume is probably the most important metric, but volume too can rebound as newly formed ice will thicken quite quickly. To around 1M anyway. That doesn't say much about the quality of that ice though.

I don't believe there will be any significant rebound. If this freeze season is anything like last year then I don't want to imagine what will happen when the sub comes back.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2823 on: November 02, 2016, 11:06:56 AM »
I agree that volume is probably the most important metric, but volume too can rebound as newly formed ice will thicken quite quickly. To around 1M anyway. That doesn't say much about the quality of that ice though.

I don't believe there will be any significant rebound. If this freeze season is anything like last year then I don't want to imagine what will happen when the sub comes back.

Usually it breaks through the ice..

DoomInTheUK

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Re: Home brew AMSR2 extent & area calculation
« Reply #2824 on: November 02, 2016, 12:51:39 PM »
Usually it breaks through the ice..

Very good. ::)

It doesn't  matter how many times I try and proof read a post, typos can still wriggle past.

Of course I meant "when the sun comes back".

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Re: Home brew AMSR2 extent & area calculation
« Reply #2825 on: November 02, 2016, 03:40:42 PM »
Usually it breaks through the ice..

Very good. ::)

It doesn't  matter how many times I try and proof read a post, typos can still wriggle past.

Of course I meant "when the sun comes back".

More and more, it breaks through the ice (from the top, via melting). ::)
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Re: Home brew AMSR2 extent & area calculation
« Reply #2826 on: November 02, 2016, 06:30:09 PM »
Attaching extent and area for the Arctic Basin ( including CAB, Beaufort, Chukchi, ESS and Laptev) calculated from sea ice concentration from three sources.

Normally the lines for recent years lie close together somewhere in the begin of November. Also here 2016 does not play with the rest.

Okono

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Re: Home brew AMSR2 extent & area calculation
« Reply #2827 on: November 02, 2016, 07:14:12 PM »
As you point out, the Earth is a "slightly" more complicated system than that.  I wouldn't be stunned if a law based on Brownian motion(Boltzmann) is dominated by another process entirely(circulation patterns) in such a system.

I'll put any new speculation in another thread.  But actual science on part of the discussion we already had, courtesy of jdallen via Colorado Bob on the main freeze season thread:

"Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification."

http://onlinelibrary.wiley.com/wol1/doi/10.1002/2016GL070526/abstract

So, that brings me back to my original thought: if heat transport is accelerating *because of* that distribution, and that distribution has lower total OLR, arctic amplification actually represents increased heat retention by the Earth system, and we should be looking at that, not the Arctic in vacuo.

Yay, more positive feedback.  I love getting positive feedback.
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Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2828 on: November 18, 2016, 08:56:03 AM »
Extent and area dipping:

Update 20161117.

Extent: -50.1 (-1200k vs 2015, -1429k vs 2014, -1084k vs 2013, -559k vs 2012)
Area: -24.6 (-1150k vs 2015, -1437k vs 2014, -1064k vs 2013, -536k vs 2012)

The cause is shown in the attached animation (click to start).

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2829 on: November 18, 2016, 09:10:50 AM »
Amazing. Not just drift and compaction, but what seems like actual melting near FJL, mid-November.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2830 on: November 18, 2016, 10:18:01 AM »
Amazing. Not just drift and compaction, but what seems like actual melting near FJL, mid-November.

Ice floats that are moving substantially during the 24 hours that the satellite is making its daily observations will appear lower in concentration or even (temporary) disappear. That may explain some or all of that "melting".

JimboOmega

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Re: Home brew AMSR2 extent & area calculation
« Reply #2831 on: November 18, 2016, 09:46:09 PM »
Extent and area dipping:

Update 20161117.

Extent: -50.1 (-1200k vs 2015, -1429k vs 2014, -1084k vs 2013, -559k vs 2012)
Area: -24.6 (-1150k vs 2015, -1437k vs 2014, -1064k vs 2013, -536k vs 2012)

The cause is shown in the attached animation (click to start).

Thanks for the update! What determines when we get them?

This is a huge area/extent gap, but I still see lots of potential for catch up before the sun rises and albedo becomes a factor again. We have several months before that!

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2832 on: November 19, 2016, 09:40:56 AM »
Things are getting really strange in the Arctic, fat century declines when the ice should be increasing at max speed.

Update 20161118.

Extent: -130.7 (-1273k vs 2015, -1616k vs 2014, -1264k vs 2013, -817k vs 2012)
Area: -142.8 (-1200k vs 2015, -1650k vs 2014, -1222k vs 2013, -778k vs 2012)

Attached delta map shows that all major fronts contribute.

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2833 on: November 19, 2016, 01:49:50 PM »
The Atlantic front's location is more or less where it was in the peak of summer. Unbelievable.

Shared Humanity

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Re: Home brew AMSR2 extent & area calculation
« Reply #2834 on: November 19, 2016, 05:13:34 PM »
I have a question. We all observed the highly dispersed and fractured state of the ice at the end of this just concluded melt season. Could these retreating boundaries along the entire ice edge suggest an Arctic wide compaction is occurring?

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2835 on: November 19, 2016, 07:23:23 PM »
I have a question. We all observed the highly dispersed and fractured state of the ice at the end of this just concluded melt season. Could these retreating boundaries along the entire ice edge suggest an Arctic wide compaction is occurring?
My thought as well, but eyeballing Wipneus' charts of Arctic Basin extent and area, it seems both have gone down at about the same proportion, while in a compaction I would assume area to remain roughly the same.

etienne

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Re: Home brew AMSR2 extent & area calculation
« Reply #2836 on: December 18, 2016, 09:08:53 AM »
Hello,

Here is an update of my Yearly average sea ice extent graph.


The main thing that suprises me is that we are not yet so much out of trend. Years like 1990, 1995, 2007 were lower. 2011-2012 were similarely out of trend. A "good" melting year in 2017 would have a dramatical impact on sea ice.

For the german speaking people, there is a Geolino Extra (magazine for childrens 10-14 years old) on climate change that is ok. I just don't understand why they are so much against palm oil and they missed the Antarica issue. It comes with a DVD of a "BBC earth" emission "On thin ice" from 2011 that is also good.

Best regards,

Etienne

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #2837 on: December 18, 2016, 10:33:55 AM »
Wipneus gets a (well hidden) mention in the Guardian:

The 12 key science moments of 2016

Scroll down to number 11. Pause at number 9 on the way.

Here's the current state of play:
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2838 on: December 22, 2016, 09:13:35 AM »
Near century drops today:

Update 20161221.

Extent: -81.1 (-528k vs 2015, -984k vs 2014, -715k vs 2013, -467k vs 2012)
Area: -98.5 (-731k vs 2015, -1103k vs 2014, -986k vs 2013, -649k vs 2012)

Caused by the ice retreat around Franz Josef Land:

Juan C. García

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Re: Home brew AMSR2 extent & area calculation
« Reply #2839 on: December 22, 2016, 06:08:07 PM »
Near century drops today:

Update 20161221.

Extent: -81.1 (-528k vs 2015, -984k vs 2014, -715k vs 2013, -467k vs 2012)
Area: -98.5 (-731k vs 2015, -1103k vs 2014, -986k vs 2013, -649k vs 2012)

Caused by the ice retreat around Franz Josef Land:

In the last Wipneus picture, the North Pole seems so close, that I wonder if we will have a North Pole ice-free in 2017.
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.

be cause

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Re: Home brew AMSR2 extent & area calculation
« Reply #2840 on: December 22, 2016, 07:07:20 PM »
we may never see an ice covered pole again ...
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2841 on: December 22, 2016, 07:11:03 PM »
we may never see an ice covered pole again ...
I am sure we will, but at some point in 2017 it could indeed be ice free.

Jim Williams

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Re: Home brew AMSR2 extent & area calculation
« Reply #2842 on: December 22, 2016, 09:24:55 PM »
we may never see an ice covered pole again ...
I am sure we will, but at some point in 2017 it could indeed be ice free.

You planning on living forever?  It ain't gone yet...but sometime next fall it will be.

anotheramethyst

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Re: Home brew AMSR2 extent & area calculation
« Reply #2843 on: December 30, 2016, 07:05:21 AM »
we may indeed have an ice free pole next summer... followed by an ice covered pole in the winter. 

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Re: Home brew AMSR2 extent & area calculation
« Reply #2844 on: January 04, 2017, 09:00:57 AM »
No data since 2016-12-31. Not surprisingly as the raw AMSR2 data from Jaxa has also halted (the 2017 directories are there but empty until now).

With Uni Bremen there seems to be no problem, they must have some other means of accessing the data.

A-Team

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Re: Home brew AMSR2 extent & area calculation
« Reply #2845 on: January 04, 2017, 06:10:24 PM »
Quote
raw AMSR2 data from Jaxa has halted
ftp://ftp-projects.zmaw.de/seaice/AMSR2/3.125km/ is still dead, just showing blank template for all days of 2017. They have had a scattering of defective images (never fixed) through the years but never like this. Edit: they've gotten caught up to 05 Jan 17 with 03 Jan 17 still partly defective in the Chukchi region.
Quote
With Uni Bremen there seems to be no problem
SMOS thin ice has access and is showing open water again in the Chukchi on 02-03 Jan 17, just inside the Bering Strait (white arrows). There is a fair amount of RFI (unwanted gray) but not a show-stopper. Otherwise, there has been some increase in >0.5m ice, notably in the Beaufort area but very little change overall (thick ice pixel counts ~ the same, ignoring pole hole artifacts):

42,982 03
42,809 02
41,915 01
« Last Edit: January 06, 2017, 11:43:20 AM by A-Team »

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Re: Home brew AMSR2 extent & area calculation
« Reply #2846 on: January 21, 2017, 03:47:51 PM »
I've been watching the U. Hamburg Arctic Sea Ice Area and Extent graphs Wipneus has automated.  Ignoring those areas that are tied with previous years at fully iced over, I note that half of the regions (CAB, Kara, Laptev, Barents (Barentsz), Bering, Greenland and St. Lawrence) are at or near record lows-for-the-day-of-year.  Although this is an extreme occurrence, looking at what is likely to come down the pike, half of these regions (CAB, Kara and Laptev) have 'always' re-attained/maintained full ice coverage during most the 4 or 5 following months of their freezing season.  In the past, of these 7 currently record (or near record) low regions, only the Barentsz, Bering, Greenland and St. Lawrence regions (given they are not surrounded by cold land or ice) have shown variable amounts of peak ice.  It is certainly possible these 4 regions will maintain low levels of ice coverage through the rest of this freezing season.

At some point in time, given global warming trajectories, each of the 'always getting fully iced over' regions will fail to fully ice over.  (The Kara and Laptev already maxed out earlier this winter.)  Given how remarkably warm this winter has been, I'm going to watch to see if the CAB ever gets fully iced over - or if the warm Atlantic waters will keep the ice edge at bay.
Arctic ice is healthy for children and other living things.

etienne

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Re: Home brew AMSR2 extent & area calculation
« Reply #2847 on: January 25, 2017, 02:15:27 PM »
Hello,

I updated my Sea Ice Average Extent graph with the data that were available yesterday (up to January 22).
As I wasn't so happy with the global trend (green line), I decided to separate it in two periods, before (red line) and after (purpel line) January 1, 2005. I was surprized by the result, but it is in phase with other things I have seen and read, looks like there are steps on the way down.



Best regards,

Etienne
« Last Edit: January 25, 2017, 02:23:12 PM by etienne »

N00bi-Wan

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Re: Home brew AMSR2 extent & area calculation
« Reply #2848 on: January 25, 2017, 06:56:33 PM »
Interesting, thank you!

Now, from all what I read or heard (on radio) from polar research scientists, my understanding is that the recent downward turning point, bifurcation, or -possibly- first ratchet step in Arctic ocean sea ice extent occurred during the 2007 melt season.

Did you try to separate the trending in your graph in 2007?

Just curious.  :)   

crandles

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Re: Home brew AMSR2 extent & area calculation
« Reply #2849 on: January 25, 2017, 07:25:16 PM »
Tamino has done analysis to consider different rates (changepoint analysis)

for example
https://tamino.wordpress.com/2016/09/11/climate-deniers-embarrass-themselves-about-arctic-sea-ice/#more-8711

He seems to prefer change in rate with no step for Arctic extent:

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