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bbr2314

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Re: The 2017 melting season
« Reply #3050 on: July 22, 2017, 09:08:22 PM »
Both NSIDC and IJIS extent have moved into 2nd place. And the graphic below indicates that at least NSIDC may/will even take 1st place from 2011 (which started to flatten out the last week of July), and stay there until the first week in August, when the GAC took 2012 on its major downward excursion.
What good is extent if thickness is incomparable to 2012?
http://sites.uci.edu/zlabe/files/2017/07/sit_PIOMAS_mask_June17.gif
What's left over is very thin. 95% of 2 meter ice is gone now, 99% of the 3,4 and 5 meter ice too.
I agree. It is very bleak. 2012 was still melting through multi-yr ice of 2-3M thickness, 2017 is going to be feasting on 1-1.5M ice that hasn't seen a summer yet. The losses vs. all other years over the next 30 days are going to mount to absurd levels due to the volume deficit which is now going to manifest in continued area/extent drops. It's as if nearly the entire Arctic was covered in the ice of Hudson Bay.

Jim Hunt

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Re: The 2017 melting season
« Reply #3051 on: July 22, 2017, 09:17:21 PM »
JavaScript Jim.

I guess I should check my post next time!
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

be cause

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Re: The 2017 melting season
« Reply #3052 on: July 22, 2017, 10:38:02 PM »
thanks Jim for the barrow cam .. the current waves are becoming impressive .
 
I too am afraid that the arctic was primed last autumn and winter for dramatic falls in the coming weeks . That there is still a chance ( after a Spring and summer of cool conditions and no penetration of Atlantic weather ) for records to be broken shows the importance of the freezing season . 
 It was mid-August last year before the Atlantic side 'woke up' weather wise .. if similar happens this year .. well .. there is a lot of ice ready to disappear .  b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Albatross

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Re: The 2017 melting season
« Reply #3053 on: July 22, 2017, 11:33:38 PM »
Latest webcam image from Barrow shows a bulldozer fixing a breach in the earth sea wall :o

Dharma Rupa

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Re: The 2017 melting season
« Reply #3054 on: July 22, 2017, 11:54:34 PM »
Less ice volume means less ice to melt means a smaller freshwater lens means a weaker halocline means a warmer ocean.  Just how dark does it have to get before the water vapor condenses out and the atmosphere begins to act like a desert again?

I think the next freezing (?) season will be more interesting than this melting season.


Cook

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Re: The 2017 melting season
« Reply #3055 on: July 23, 2017, 12:14:53 AM »
Latest webcam image from Barrow shows a bulldozer fixing a breach in the earth sea wall :o

I think they need to get Donald to put his finger in it. In the long term it will do about as much good. I expect that coast will receded quite rapidly in the coming years.

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Re: The 2017 melting season
« Reply #3056 on: July 23, 2017, 12:34:08 AM »
What good is extent if thickness is incomparable to 2012?
http://sites.uci.edu/zlabe/files/2017/07/sit_PIOMAS_mask_June17.gif
What's left over is very thin. 95% of 2 meter ice is gone now, 99% of the 3, 4 and 5 meter thick ice too.
This takes that graphic and removes ice below 2 metres, and shows only (June) 2012 and 2017.
What do you guys think?
How much overall thickness loss is possible in 6-8 weeks left? Not 2 metres I wouldn't think.
Maybe 1 metre?
« Last Edit: July 23, 2017, 12:49:36 AM by Thomas Barlow »

Coffee Drinker

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Re: The 2017 melting season
« Reply #3057 on: July 23, 2017, 12:34:33 AM »
Latest webcam image from Barrow shows a bulldozer fixing a breach in the earth sea wall :o

They seem to work on that sea wall every year. One problem in Barrow is the lack of strong grass (like on dikes in Netherlands and co) that could stabilize the wall.

So they have to fix it year after year. Only solution may be a proper concrete structure there or relocate the town. Or at least design the dike according to latest technology. The current wall does not look very professional. Its really just some earth and not a proper dike.

« Last Edit: July 23, 2017, 12:42:44 AM by Coffee Drinker »

VeliAlbertKallio

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Re: The 2017 melting season
« Reply #3058 on: July 23, 2017, 02:15:10 AM »
I have thought about the same comparison. It means we will see winter ice forming, most of it then going through summer, if not all. Once this happens, there is an important change, however: The inversion of Arctic Ocean re-freeze. The ocean currently freezes from the centre ice pack towards perimeter, after the central ice is gone, the sea ice starts first forming on the coasts, then slowly progressing its way towards the centre that may stay open very long due to storms. I expect the onset of freezing season proper then reaching comparable ice area 6-8 weeks later. It will also be volatile as winds, waves, and ocean currents will break thin ice pace many times over.

Both NSIDC and IJIS extent have moved into 2nd place. And the graphic below indicates that at least NSIDC may/will even take 1st place from 2011 (which started to flatten out the last week of July), and stay there until the first week in August, when the GAC took 2012 on its major downward excursion.
What good is extent if thickness is incomparable to 2012?
http://sites.uci.edu/zlabe/files/2017/07/sit_PIOMAS_mask_June17.gif
What's left over is very thin. 95% of 2 meter ice is gone now, 99% of the 3,4 and 5 meter ice too.
I agree. It is very bleak. 2012 was still melting through multi-yr ice of 2-3M thickness, 2017 is going to be feasting on 1-1.5M ice that hasn't seen a summer yet. The losses vs. all other years over the next 30 days are going to mount to absurd levels due to the volume deficit which is now going to manifest in continued area/extent drops. It's as if nearly the entire Arctic was covered in the ice of Hudson Bay.

Tigertown

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Re: The 2017 melting season
« Reply #3059 on: July 23, 2017, 02:19:51 AM »
Dharma Rupa,
Quote
I think the next freezing (?) season will be more interesting than this melting season.
That's what I have been saying for a long time now.

Thomas Barlow,
Quote
How much overall thickness loss is possible in 6-8 weeks left? Not 2 metres I wouldn't think.
Maybe 1 metre?

 Don't forget the late season "Garlic Press" and don't gauge what it is capable of from last year. Thinner and smaller floes may not stop it from flowing as easily as last year's ice did.

Rob Dekker

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Re: The 2017 melting season
« Reply #3060 on: July 23, 2017, 06:25:35 AM »
Rob, correct me if I'm wrong, but I think you're using the published NSIDC September monthly averages as the "control" for your model. (As that's what the SIPN uses, I consider that to be reasonable assumption.  ;) )

A few days ago, during a dialogue with Neil on the ASIB, I posted an alternative set of results for the September average. Instead of using the NSIDC's much-criticised legacy technique of spatio-temporal averaging to derive the monthly value, the alternate approach is to simply use the arithmetic mean of the September daily values.

Unsurprisingly, the alternate version is consistently somewhat lower, but by a varying amount from year to year.

If you get bored one day, you might try a hindcast using this as a slightly modified control.

Col1=Year; Col2=published NSIDC Sept average, Col3=modified version, Col 4= difference
(All SIE values in millions of sq kms.)

1979      7.22      7.051    -0.169
1980      7.86      7.667    -0.193
1981      7.25      7.138    -0.112
1982      7.45      7.302    -0.148
1983      7.54      7.395    -0.145
....
2009      5.39      5.262    -0.128
2010      4.93      4.865    -0.065
2011      4.63      4.561    -0.069
2012      3.63      3.566    -0.064
2013      5.35      5.208    -0.142
2014      5.29      5.220    -0.070
2015      4.68      4.616    -0.064
2016      4.72      4.505    -0.215

It would be interesting to see if that significantly* affects the SD of the residuals. (* No pun intended, after a punishing 5 hours watching Le Tour de France, my brain could not dredge up an appropriate synonym.)

Hi Bill, today I finally had a chance to run your numbers.
It turns out that if we use your 'daily average' method rather than the NSIDC method to determine September SIE average, using my method does not significantly change the 'predictability'.

With NSIDC September numbers I obtain 342 k km^2 Standard Deviation over the residuals, while with your 'daily number' average I obtain 340 k km^2. This is after adjusting the formula to obtain best correlation.

That is insignificantly better, and thus suggests that the "varying amount from year to year" you report is just noise.

Prediction using my method with your (daily average) number predicts 5.31 M km^2 left over in September, which is (as expected) a bit lower than predicting the standard NSIDC numbers for September.

Also, someone earlier in this thread asked about my method predicting the 2013 and 2014 rebound years. And indeed, in 'hindcast' mode (using data through 2015) my method predicted 5.13 and 5.03 respectively for 2013 and 2014. I promised to run the model in 'forecast' mode (using only data up until 2012) and that results in a slightly changed formula and a slightly higher SD, but still predicts 5.09 and 4.99 for 2013 and 2014. So the method is consistent in reproducing much of the 'rebound' years, regardless of 'hindcast' or 'forecast' mode.

Where it gets really interesting is if, instead of trying to predict ice 'extent', we let the model predict ice 'area' in September. That is the last column in the NSIDC data here :
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/monthly/data/N_09_extent_v2.1.csv

The September SI 'area' number is much more accurately predictable !
Using the 1992-2015 data set, I obtain a SD of the residuals of just 270 k km^2. MUCH better than trying to predict 'extent' (340 k km^2) or using linear trend (about 550 k km^2).
For 2017, my model predicts 3.85 M km^2 NSIDC 'area' in September.
This is still higher than 2013 (3.77) and 2014 (3.73) so no matter which method we use, my model still predicts that 2017 will be a 'rebound' year.

That's why I'm still optimistic, even though the persistent decline in SIE is worrysome. We should REALLY start to see some reduction in SIE decline rate very soon for my prediction to remain somewhat believable.

We'll see what the next weeks bring us.
« Last Edit: July 23, 2017, 06:45:52 AM by Rob Dekker »
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Tigertown

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Re: The 2017 melting season
« Reply #3061 on: July 23, 2017, 08:25:26 AM »
Starting to see large areas of mush. Wrangel at top left.

cesium62

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Re: The 2017 melting season
« Reply #3062 on: July 23, 2017, 08:38:33 AM »
That's why I'm still optimistic, even though the persistent decline in SIE is worrysome. We should REALLY start to see some reduction in SIE decline rate very soon for my prediction to remain somewhat believable.

We'll see what the next weeks bring us.

50 days ago, the Slater prediction was predicting that extent losses would slow quite a bit starting about now.

Looking at Wipneus' regional graphs, Chuckchi, ESS, Greenland Sea, and Kara extent losses historically start to slow about now; Hudson and Barents don't have much further to fall; CAA and Beaufort are at decision points as to whether to follow a rebound year path or not; Baffin doesn't look like it will change its rate of loss much; and Laptev and CAB look to me like they might sustain some losses.  So, on balance, I could see the case for a slowdown in extent losses...

Rob Dekker

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Re: The 2017 melting season
« Reply #3063 on: July 23, 2017, 08:53:01 AM »
So, on balance, I could see the case for a slowdown in extent losses...

Thanks, Cesium. Yet to tie with 2013 and 2014 we would need to see sustained reduction in SIE losses from now till the end of September. The CAB would need to 'hold' its integrity for one.
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Tigertown

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Re: The 2017 melting season
« Reply #3064 on: July 23, 2017, 08:56:40 AM »
The CAA is just waiting on the least little push before it starts flowing south.

Andre Koelewijn

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Re: The 2017 melting season
« Reply #3065 on: July 23, 2017, 09:00:53 AM »
So they have to fix it year after year. Only solution may be a proper concrete structure there or relocate the town. Or at least design the dike according to latest technology. The current wall does not look very professional. Its really just some earth and not a proper dike.

A concrete structure would get undermined, because the root cause here is an increase of wave action over the year. This leads to a more inland location of the beach, unless they could apply something like beach nourishment (i.e. adding sand to the beach, dredged from an offshore location), as applied at the sandy part of the coast of the Netherlands.

Given the limited resources (equipment and money) they have, it doesn't look as unprofessional as suggested. But in the long (?) run, inland relocation seems necessary.

NeilT

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Re: The 2017 melting season
« Reply #3066 on: July 23, 2017, 11:55:39 AM »
We'll see what the next weeks bring us.

I have a question Rob.

If you take 1992 to 2006 figures, does your model predict 2007?
If you take 1992 to 2011 figures does your model predict 2012?

I believe these years were such a surprise because you can't model these events with our current level of understanding and, certainly, with our current level of monitoring and measurement.

From what I can see from the overheads the CAB is starting to destabilise, in many places right up to 85N, from Svalbard, swinging east all the way round to the Beaufort.

It may be that this does not, in the end, impact melt and the CAB may retain integrity and slow down both extent and area losses.

However, as we saw in 2012, when the ice is so weak and so unstructured, the weather has a knack of messing all the predictions up.
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Re: The 2017 melting season
« Reply #3067 on: July 23, 2017, 02:11:08 PM »
The Typhoon autogun in the Pacific and the effects on the Beaufort gyre dynamics have been giving me a very sick feeling in my gut the last 24hrs. It looks very ugly indeed what is unfolding.
 First Animation:
 Total Precipital Water and surface winds,
 Winds at 1000hpa,
 Temps and winds at 850hpa,
 3hr precipitations of 6mm over the the outer CAA and 850hpa winds,
 and total cloud water simular to the record flood last week in Japan nth of Barrow with 700hpa winds.
 This Junks looking to continue for some time with south and west winds from Norway to Chukchi to Greenland coastal. If not dumping lots of water vapour into the basin, its making hot foehn winds off Europe, Siberia, Alaska, the CAA, and Greenland. And pushing warm Pacific and Atlantic waters in at accelerated rates.

As for the effects on the Beaufort Gyre and Ice.
The Eastward surface drift from all these Westerly's, is and will continue to disperse the loose fringes and fresh meltwater to the right, de-consolidating the pack and exposing the meltwater and river Fluxs to rising salinity by mixing with the inbound waters they are riding over above the shallow continental shelves. Bottom structure and Methane venting will enhance this of course.
First frame shows:
- Along with Pacific end SST anomalies, marked where the spreading meltwater is butting up against the still eastward moving pacific waters east in the ESS and a strong and large mixing vortex in process. These are popping up all along the meltwater front and the Strong inflow through Bering has in the last few days swung from heading in that direction to straight ahead towards the pole sliding down the slope under the Chukchi front, to bending to the east and heading for the CAA along the shelf instead.
Second Frame:
- SST of 10.7C on strong inflow Thru Bering just mentioned. Mixing Vortexes even clearer. Clockwise rotating Pacific water bending northward as its sucked under anticlockwise rotating melt and debris intent on escape from the pack and heading south, you gotta expect them.
Third Frame:
- 1.72m swells eastbound, against current, into the Beaufort pack and CAA. Slightly bigger ones actually heading straight north into the pack from Bering in the Chuckchi.
Fourth  Frame:
- Track log plots of ITP buoys 97 in the Beaufort and 95 at 85nth heading for Fram.
Fifth  Frame:
- Observe the deep core of fresher water penetrating the hHalocline surface to depth in the lefthand ITP 97 plot. Deep mixing events on its fringes. This the Gyres "flywheel", a large reserve to maintain the Halocline, in the middle of the Canadian basin. Not much disturbance in the Temperature plots above it. A little warming and thinning  of the Gulfstream Layer it penetrates from energy extracted as its feeds have punched through. About 0.5 degrees warmer and around 1% saltier than the Layer above the Atlantic from about 300m to 50m from the surface. Though recently the surface temp has spiked to just below Zero as we've noticed on the Buoys thread. ITP 97 seems to be in the fringes of the pack where the deep Gyre ramps up the Alaskan slope Right about in the middle of this
Frame 5, today's worldview shot.
-ITP 97 right about in the middle.
Frame 6 shows the westbound current coming up here at 0C.

So anyway, the Gulfstream water that has been surfacing at 15-16C around, Svalbard and FJL, and just loves to hug the right by the Right Hand Rule of mr Coriolis North.
 Should it not meet Pacific, and surface stuff head on at Severnaya Zemlya thats Westbound as traditional in a high pressure dominated Eastern Basin. Keen to take it by the hand and ride it out off the shelf into the deeper basin...
Perhaps Gulf Snake will be fresh and warm enough to climb on top, or even socialise a little with Pacific eel. Assisted by big late snow-melts and an open Russian coast, and a slide beneath a few thousand km of fresh melt pool south of Norway.
With a largely Low pressure dominated east with a reversing Gyre, and Cooler inbound stuff from a full or partial anticlockwise deep salty racetrack that it can team up with and python coil the heart of the Ocean.
Then instead of a big reserve of low density fresh pycnocline pushed down in the middle of the eastern Basin.....
 That which is there will all be flinging itself out through the CAA and down both coasts of Greenland , as the Turbo Pump from both Oceans swirls all around squeezing it out from below.
I'm deeply worried that this is starting already. :-\  ???  :P

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liefde

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Re: The 2017 melting season
« Reply #3068 on: July 23, 2017, 02:16:02 PM »
The CAA is just waiting on the least little push before it starts flowing south.
Or warm water starts pushing North. Ocean SSTs are warmer than ever at the edges of the poles. It's going to melt from below and since the sun is appearing there too, it doesn't have a chance. We may see extent stabilize (although I also doubt that it will), but volume, thickness, is going to drop to record lows, way below 2012, I don't think anyone expects otherwise.

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Re: The 2017 melting season
« Reply #3069 on: July 23, 2017, 03:59:49 PM »
The CAA is just waiting on the least little push before it starts flowing south.
Or warm water starts pushing North. Ocean SSTs are warmer than ever at the edges of the poles. It's going to melt from below and since the sun is appearing there too, it doesn't have a chance. We may see extent stabilize (although I also doubt that it will), but volume, thickness, is going to drop to record lows, way below 2012, I don't think anyone expects otherwise.
This "anyone" expects otherwise, at least as regards extent (using JAXA data). Extent reduction from maximum by July 22 is, on average (for the last 10 years), just over 70% of the total reduction for the year. Not a lot of the season left. Extent reduction this year is currently some 4 percent below the average for the last ten years. Due to high positive SST anomalies and low volume (and therefore reduced average thickness), an increased late season melt is certainly on the cards. I do not expect that to result in a new record low extent, as this would require an extraordinary series of meteorological events. A 2nd lowest extent (and a record low volume) is still eminently possible.
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oren

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Re: The 2017 melting season
« Reply #3070 on: July 23, 2017, 04:12:07 PM »
Not a lot of the season left. Extent reduction this year is currently some 4 percent below the average for the last ten years. Due to high positive SST anomalies and low volume (and therefore reduced average thickness), an increased late season melt is certainly on the cards. I do not expect that to result in a new record low extent, as this would require an extraordinary series of meteorological events. A 2nd lowest extent (and a record low volume) is still eminently possible.
Thanks gerontocrat. If I understand your table correctly, the required extent loss is almost the same as actually happened in 2012 from now til minimum. Extraordinary indeed, but still possible, especially as volume is tracking 2012 as well. I'd give extent a 20% chance of a record, but the next couple of weeks are critical.
As for volume, I'd give it a 50% and there's still much time to get there. A lot depends on a GAC or two, but even average volume loss could go far.

gerontocrat

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Re: The 2017 melting season
« Reply #3071 on: July 23, 2017, 04:27:25 PM »
Hullo Oren,
To quote from my reply to your post on IJIS.

"I believe that the late melt in 2012, some 30 percent or nearly 1 million km2 above the average, is unique in the satellite record, but I may be wrong. A one in ten event it certainly was not."

Also a  50% chance of a record volume seems eminently possible - last winter and spring set it up and a bit more melt will finish the job. But a record low extent ?
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Thawing Thunder

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Re: The 2017 melting season
« Reply #3072 on: July 23, 2017, 04:33:10 PM »
If I understand your table correctly, the required extent loss is almost the same as actually happened in 2012 from now til minimum. Extraordinary indeed, but still possible, especially as volume is tracking 2012 as well.

It is tracking 2012 volume AND has very thin ice in areas especially exposed to melt like the Beaufort Sea. I'm not sure that anything extraordinary has to happen to equal 2012. I still expect the CA to show bigger open areas at the beginning of August and that those holes will push extent and area toward a new record. I know, it's all speculation and depends on something we don't really see: Bottom melt.
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Re: The 2017 melting season
« Reply #3073 on: July 23, 2017, 05:30:30 PM »
   ....
As for the effects on the Beaufort Gyre and Ice.
   ....

Much as I appreciate your thorough analysis and accompanying graphics, I'm having trouble piecing it all together.  Yes, the Arctic is in for considerable heat and moisture advection from the Pacific.  But won't this be mitigated by the lows protecting areas of the central ice pack?

   ....
That which is there will all be flinging itself out through the CAA and down both coasts of Greenland ...

I don't see much indication of this in the next week or so.

cesium62

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Re: The 2017 melting season
« Reply #3074 on: July 23, 2017, 07:27:24 PM »
A 2nd lowest extent (and a record low volume) is still eminently possible.

Sounds difficult.  Thin ice would have to be scattered more than usual.  Scattered ice is likely to scatter to the south and melt.

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Re: The 2017 melting season
« Reply #3075 on: July 23, 2017, 07:45:53 PM »
A 2nd lowest extent (and a record low volume) is still eminently possible.

Sounds difficult.  Thin ice would have to be scattered more than usual.  Scattered ice is likely to scatter to the south and melt.
So that could be a sudden death event in SIE, what is statistically unpredictable

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Re: The 2017 melting season
« Reply #3076 on: July 23, 2017, 08:00:39 PM »
The September SI 'area' number is much more accurately predictable !  Using the 1992-2015 data set, I obtain a SD of the residuals of just 270 k km^2. MUCH better than trying to predict 'extent' (340 k km^2)

I think you should normalize the data when comparing the standard deviations for area vs. extent residuals.  The September area is always less than the September extent, by about a factor of 0.7 on average.  So it's no surprise that the standard deviation of the residuals for September area is less than for September extent.

cesium62

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Re: The 2017 melting season
« Reply #3077 on: July 23, 2017, 08:02:44 PM »
Hullo Oren,
To quote from my reply to your post on IJIS.

"I believe that the late melt in 2012, some 30 percent or nearly 1 million km2 above the average, is unique in the satellite record, but I may be wrong. A one in ten event it certainly was not."

2017 has comparable extent and comparable volume to 2012, and is a few years after 2012.  2007 contended with thicker stronger ice than 2012 did.  If you normalize for the quality of the ice, a one in five event does not seem that unlikely.  If you also take into account that the seas are a fraction of a degree warmer, 2017 doesn't need as rare of an event as 2012 experienced.

https://skepticalscience.com/print.php?r=433
"
Paul A. Newman, chief scientist for Atmospheric Sciences at NASA's Goddard Space Flight Center estimated that there have been about eight storms of similar strength [to 2012] during the month of August in the last 34 years of satellite records - one every 4 to 5 years.
"
"
The scientific literature indicates that Arctic storms may be becoming more intense, in part due to increased open water as the sea ice continues its long-term human-caused decline.
"


Thomas Barlow

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Re: The 2017 melting season
« Reply #3078 on: July 23, 2017, 08:14:31 PM »
Explorer expects NP to be open water this summer. Plans to sail to the pole in a yacht.

http://www.pressreader.com/new-zealand/the-dominion-post/20170724/282089161833092

helorime

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Re: The 2017 melting season
« Reply #3079 on: July 23, 2017, 08:34:19 PM »
We are in that spot where all the low years converge.  The divergence has been in the 2nd week in August. Sometimes I think that a lot of us on this forum overthink and over-predict.  The ice is not in good shape.  Weather matters a lot.  Calculating based on % changes, and average drops, may not be all that informative.  This is where we are.  We can see what the ice is like.  Will August be favorable for the ice?  Will August bring storms and shredding and transport more warm water?  We had a low maximum this year. 2012 had a relatively high one, so the decrease in area and extent are inherently different.
Any sufficiently advanced technology is indistinguishable from magic.

Thomas Barlow

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Re: The 2017 melting season
« Reply #3080 on: July 23, 2017, 08:37:18 PM »
So, on balance, I could see the case for a slowdown in extent losses...

Thanks, Cesium. Yet to tie with 2013 and 2014 we would need to see sustained reduction in SIE losses from now till the end of September. The CAB would need to 'hold' its integrity for one.
I think there is more peripheral ice (eg. Baffin Bay, Greenland Sea, Novaya Zemlya) than many previous years, and that will disappear, causing a larger than usual drop in extent, since it is all adding to an illusory extent right now. The CAA may hold out better than usual, as it seem thicker than usual, but if the CAA does get a decent loss, then the overall extent could drop, even if the CAB losses are at a relatively normal rate.

Thawing Thunder

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Re: The 2017 melting season
« Reply #3081 on: July 23, 2017, 09:03:34 PM »
2017 has comparable extent and comparable volume to 2012, and is a few years after 2012.  2007 contended with thicker stronger ice than 2012 did.  If you normalize for the quality of the ice, a one in five event does not seem that unlikely.

We are in that spot where all the low years converge.  The divergence has been in the 2nd week in August. ...  The ice is not in good shape. ... We had a low maximum this year. 2012 had a relatively high one, so the decrease in area and extent are inherently different.

I think there is more peripheral ice (eg. Baffin Bay, Greenland Sea, Novaya Zemlya) than many previous years, and that will disappear, causing a larger than usual drop in extent, since it is all adding to an illusory extent right now. ...

Just posting three quotes that sum up my own point of view very well.
The Thunder was father of the first people, and the Moon was the first mother. But Maxa'xâk, the evil horned serpent, destroyed the Water Keeper Spirit and loosed the waters upon the Earth and the first people were no more.

Pi26

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Re: The 2017 melting season
« Reply #3082 on: July 23, 2017, 09:07:12 PM »
Today Worldview has very clear but imho horrible images of the area north from Svalbard and north to north east from Greenland.



« Last Edit: July 23, 2017, 11:09:17 PM by Pi26 »

Ninebelowzero

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Re: The 2017 melting season
« Reply #3083 on: July 23, 2017, 10:07:19 PM »
Explorer expects NP to be open water this summer. Plans to sail to the pole in a yacht.

http://www.pressreader.com/new-zealand/the-dominion-post/20170724/282089161833092

A dangerous undertaking.

Much safer flying there or are these parallel (military?) contrails of the 21st July North of Greenland just a mapping artifact?

Pavel

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Re: The 2017 melting season
« Reply #3084 on: July 23, 2017, 10:21:51 PM »
Today Worldview has very clear but imho horrible images of the area north from Svalbard and north to north east from Greenland.
It definitely not looks like 2-4 meters thickness ice. There's blue ocean near Svalbard and the rest of the ice pack is gray and rather dispersed than compacted. I guess PIOMAS does not allow for warm waters and bottom melting near Svalbard
« Last Edit: July 23, 2017, 10:29:08 PM by Pavel »

Hyperion

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Re: The 2017 melting season
« Reply #3085 on: July 23, 2017, 11:54:45 PM »
The lows don't protect the Centre of the pack if the Ice drift in the Beaufort is anticlockwise as they promote dispersion. If the Clockwise gyre is fading near the surface or thinner ice incapable of feeding on its current then the pack is being wind driven anticlockwise and everything wants to fling itself outwards. While the lows continue to draw in warmth and moisture from far away.

The loose stuff that's survived melting out as its flung out in the ESS and Chukchi for example has been pushed into the Beaufort.  The melt-water main exit route is down the Coasts of Greenland, and through the CAA Which has Just mobilized in all channels. And  and the big SSTA anomaly south and west of Greenland is the Evidence.
Note the Big push of hot gulfstream along the western coast of Russian Arctic, and the below normal temps from the meltwater being flung at the coast past where its got to.
And in the Chukchi how the Pacific inflow is accelerating and pushing along the nth Alaskan coast, while meltwater is being flung against the Beaufort coast in the corner against the CAA.

People hope these wider spread cooler surfaces will protect the central pack, but they stop the heat being released from the incoming stuff below. And the central pack is being shredded and opened up with more bottom melt and more surface area exposed to air and water and more mixing of near surface air and water. The claim that lower average temps over the pack are Evidence to promote theories that the Ice is in a recovery year, while it is actually Evidence of increased energy being taken up by Ice melting and more exposed and more turbulent water in active rubblefields.

The Halocline is disintegrating by enhanced Ekman pumping from surface drift in the opposite direction to the warmer waters below. And increased warm inflow and fresh melt eviction.

And that big plug of low density warm water that I drew attention  to above that's been pushed down in the central eastern basin, due to the high pressure core effect of a clockwise gyre? Its becoming Increasingly FREE to bob up like a cork and melt and disperse the central pack in a big flushout from below.

   ....
As for the effects on the Beaufort Gyre and Ice.
   ....

Much as I appreciate your thorough analysis and accompanying graphics, I'm having trouble piecing it all together.  Yes, the Arctic is in for considerable heat and moisture advection from the Pacific.  But won't this be mitigated by the lows protecting areas of the central ice pack?

   ....
That which is there will all be flinging itself out through the CAA and down both coasts of Greenland ...

I don't see much indication of this in the next week or so.
« Last Edit: July 24, 2017, 12:08:03 AM by Hyperion »
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
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jplotinus

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Re: The 2017 melting season
« Reply #3086 on: July 23, 2017, 11:59:15 PM »
Explorer expects NP to be open water this summer. Plans to sail to the pole in a yacht.

http://www.pressreader.com/new-zealand/the-dominion-post/20170724/282089161833092

A dangerous undertaking.

Much safer flying there or are these parallel (military?) contrails of the 21st July North of Greenland just a mapping artifact?


-9°

Contrails like those you spotted are common in the high Arctic and often show up on worldview. Sometimes they form X patterns, other times they are 1000+km in length. I know of no source that assesses the environmental or weather impacts of Arcticcontrails. If posters are aware of linkable articles on Arctic contrails, I'd be much obliged for posting of such links. I'm not here speaking about the conspiracy theory links. Those are easy to find.

Hyperion

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Re: The 2017 melting season
« Reply #3087 on: July 24, 2017, 12:15:37 AM »

Quote


-9°

Contrails like those you spotted are common in the high Arctic and often show up on worldview. Sometimes they form X patterns, other times they are 1000+km in length. I know of no source that assesses the environmental or weather impacts of Arcticcontrails. If posters are aware of linkable articles on Arctic contrails, I'd be much obliged for posting of such links. I'm not here speaking about the conspiracy theory links. Those are easy to find.

I wish They'd send us some Pics. It looked like a military formation to me.
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

VeliAlbertKallio

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Re: The 2017 melting season
« Reply #3088 on: July 24, 2017, 12:26:41 AM »
Images of a warm Atlantic water current which is pushing beneath sea ice in the Fram Strait. A large landfast piece of sea ice will shortly detach. Further fractures appeared in the land fast ice. A removal of yet another slow-down feature slowing southward sea ice transport from the Arctic.

Jim Hunt

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Re: The 2017 melting season
« Reply #3089 on: July 24, 2017, 12:56:02 AM »
Explorer expects NP to be open water this summer

See: http://www.arcticmission.com/

Some thoughts from last year:

http://GreatWhiteCon.info/2016/09/could-northabout-sail-to-the-north-pole/

More at:

https://www.thetimes.co.uk/article/pen-hadow-launches-bittersweet-mission-to-sail-to-north-pole-xq82c9225

You have to give the Sunday Times your email address, which reveals:

Quote
For his new record attempt, Hadow and his nine-strong team will take two yachts on a 3,500-mile round trip from Nome in Alaska to the pole, using satellites to find a route through the ice and avoid getting stuck. He will fly to Alaska to join his team members on Saturday.

If all goes to plan, he will arrive at the pole between August 15 and early September, about 510 miles further north than anyone has sailed before.

The risk of ships becoming trapped in ice was once very real. In 1893, at the start of the golden age of polar exploration, the Norwegian Fridtjof Nansen wedged his three-masted schooner, Fram, into the pack ice, trusting its natural drift to deliver him to the North Pole. After 18 months he tired of its slow and erratic progress and set off with dog sledges instead.

Personally I reckon the risk is still very real on Pen Hadow's planned route!
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Thawing Thunder

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Re: The 2017 melting season
« Reply #3090 on: July 24, 2017, 01:23:29 AM »
I bit the bullet, stacked one week of images from the eastern Arctic and removed the clouds manually (took hours). The images I used go from the 17th to the 23rd, latest image on top to avoid distortion by drift and melt as much as possible. Some contrast enhancement is applied.
« Last Edit: July 24, 2017, 02:06:57 AM by Thawing Thunder »
The Thunder was father of the first people, and the Moon was the first mother. But Maxa'xâk, the evil horned serpent, destroyed the Water Keeper Spirit and loosed the waters upon the Earth and the first people were no more.

Rubikscube

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Re: The 2017 melting season
« Reply #3091 on: July 24, 2017, 02:30:47 AM »
I bit the bullet, stacked one week of images from the eastern Arctic and removed the clouds manually (took hours).

Awesome

Hyperion

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Re: The 2017 melting season
« Reply #3092 on: July 24, 2017, 02:44:04 AM »
Nice pictures Veli. Darn that stuff looks translucently thin.

Further to my above analysis of Gyre and halocline issues.

Wipneus great Gif of the Kara 6-21 July borrowed from the Homebrew thread. You can see the drift repeatedly pulsing eastward and spiting chunks south to the right at the coast by watching the features. An effect visibly here operating deep into the pack.



And A-team has a great pic of 20-25 July Ice drift forecast on Piomass thread. showing the pattern thats been in effect for some time now, preserving extent on all the peripheries, while the more mobile meltwater is evicted thru the CAA and Fram.

Basically the Extent and Area figures have been getting held up by a pack repeatedly exploding outwards, while it covers the basin with an increasingly fragmented field of smaller and smaller floes and chunks of slushier and thinner and more dispersed rubble. Its primed for a crash with the first big cyclone, or even with a few little ones.

Take a good hard look at the salinity charts for ITP95 from pole to 85 sth of Svalbard, and ITP97 across the centre of the eastern basin.
There is really only 25-50 m at most of a little fresher water on the surface left. And only a few percentage points of salinity below the stuff underneath it. Its primed to form a cohesive layer hundreds of metres thick incapable of freezing in winter.
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
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greatdying2

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Re: The 2017 melting season
« Reply #3093 on: July 24, 2017, 03:21:48 AM »
I bit the bullet, stacked one week of images from the eastern Arctic and removed the clouds manually (took hours). The images I used go from the 17th to the 23rd, latest image on top to avoid distortion by drift and melt as much as possible. Some contrast enhancement is applied.
Thanks TT, that's very helpful.
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

VeliAlbertKallio

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Re: The 2017 melting season
« Reply #3094 on: July 24, 2017, 03:39:30 AM »
TT Superb! Note the albedo change to darkened surfaces covering almost half of the image on the right. Darkening of sea ice by leads in ice is probably worse than melt and rainwater pools: the sea water can mix vertically in all darkened areas in sea ice. I suspect big melt ahead in this area.
I bit the bullet, stacked one week of images from the eastern Arctic and removed the clouds manually (took hours). The images I used go from the 17th to the 23rd, latest image on top to avoid distortion by drift and melt as much as possible. Some contrast enhancement is applied.
Thanks TT, that's very helpful.

Hyperion

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Re: The 2017 melting season
« Reply #3095 on: July 24, 2017, 03:49:48 AM »
Yeah TT that gives a much more approachable view of what we have overall. What pixel size on worldview did you start with? 1km? 5km? Or have you smaller blocks with the full 250m available resolution?
We could start a thread where volunteers  team up with territories assigned, archive frames, and just clip the visible areas out for each tile . Then layer those. and perhaps cheat a little with a bit of clone brushing to fill in the holes.
Its pretty easy with the Lassoo tool and control and shift keys on my oldschool paintshop pro4 to do that. Dunno about others apps.

tried a few of psp tools on it. Only thing I could do that might have brought out a little detail thru the clouds was max the colour saturation and a slight contrast boost.
« Last Edit: July 24, 2017, 04:51:47 AM by Hyperion »
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

LDorey

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Re: The 2017 melting season
« Reply #3096 on: July 24, 2017, 05:16:58 AM »
Hi,

Just curious, I've been lurking for a while,  and while I see a lot of pics posted, I don't see a lot posted pulling from the sentinel satilte missions, is there a reason why? ( Or is it and I'm just not realizing it)

In the same vein the sentinel 3 sat data is available now, and when I played around with it in the sentinel toolbox it looks like you could use it to really clean up the swaths and get some very clear images of the ice. I was.mostly just fooling around, but it looked like you could run algoriths against pixels based on the cloud masks. You can also use it to process the sentinel 1 and 2 data the same way. Might be easier than Photoshop. Apologies if this belongs in stupid questions  :)


Liam

Rob Dekker

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Re: The 2017 melting season
« Reply #3097 on: July 24, 2017, 06:33:34 AM »
The September SI 'area' number is much more accurately predictable !  Using the 1992-2015 data set, I obtain a SD of the residuals of just 270 k km^2. MUCH better than trying to predict 'extent' (340 k km^2)

I think you should normalize the data when comparing the standard deviations for area vs. extent residuals.  The September area is always less than the September extent, by about a factor of 0.7 on average.  So it's no surprise that the standard deviation of the residuals for September area is less than for September extent.

To 'normalize' the 'area' data does not make much physical sense.
I'd rather look at it this way : 'extent' consists of "area" plus "extent minus area", where it turns out that "area" has good correlation with melting parameters in June (land snow cover, ice concentration, area etc) but "extent minus area" (how loosely or tightly ice is distributed in the margin in September) is much more random, and much less predictable.
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Tigertown

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Re: The 2017 melting season
« Reply #3098 on: July 24, 2017, 06:51:27 AM »
The Pacific side is really getting worked over now.
Second image is a gif CLICK TO ACTIVATE  21st thru 23rd

Rob Dekker

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Re: The 2017 melting season
« Reply #3099 on: July 24, 2017, 07:41:18 AM »
I have a question Rob.

If you take 1992 to 2006 figures, does your model predict 2007?
If you take 1992 to 2011 figures does your model predict 2012?

I believe these years were such a surprise because you can't model these events with our current level of understanding and, certainly, with our current level of monitoring and measurement.

In forecast mode (using 1992-2011 data), for 2012, my method still predicts 3.83, essentially the same as in hindcast mode (3.82). The final extent was 3.62, so a reasonable prediction.
In forecast mode (using 1992-2006 data), for 2007, my method predicts 5.06, slightly higher than the 4.77 prediction in hindcast mode, but still predicting a record low. The final was 4.29 which is quite a bit lower than either forecast or hindcast mode predictions.

If I have some time, I will calculate the 'forecast' mode for every year and put it in a graph similar to the 'hindcast' graph :
This is our planet. This is our time.
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