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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #500 on: June 24, 2015, 08:58:51 PM »
Cryosphere Today has finally updated its numbers through Day 0.4740. As follows:

2015.4630  -1.2066629   8.4857779   9.6924410
2015.4657  -1.2671592   8.3374977   9.6046572
2015.4685  -1.3478416   8.1689644   9.5168057
2015.4712  -1.3161162   8.1196880   9.4358044
2015.4740  -1.2032638   8.1203060   9.3235693

Anti-climactic, of course, since Wipneus already gave us the numbers...

jdallen

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Re: 2015 sea ice area and extent data
« Reply #501 on: June 24, 2015, 10:24:15 PM »
Cryosphere Today has finally updated its numbers through Day 0.4740. As follows:

2015.4630  -1.2066629   8.4857779   9.6924410
2015.4657  -1.2671592   8.3374977   9.6046572
2015.4685  -1.3478416   8.1689644   9.5168057
2015.4712  -1.3161162   8.1196880   9.4358044
2015.4740  -1.2032638   8.1203060   9.3235693

Anti-climactic, of course, since Wipneus already gave us the numbers...
2015.4740 still looks like a glitch.
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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #502 on: June 25, 2015, 04:11:44 PM »
From today's NSIDC data update I calculate the following CT updates (by day that CT "normally" reports):

Wed       8.120306
Thu -92.5  8.027844
Fri -70.6  7.957204
Sat -123.8  7.833411

Biggest declines in Hudson (-37k), Baffin (-23k), Chukchi (-18k) and Greenland Sea (-13k).
In the attached delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up)

Neven

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Re: 2015 sea ice area and extent data
« Reply #503 on: June 25, 2015, 04:53:55 PM »
The Wed. Number (0.3) still looks like a glitch.  Given the current heat exchange, at the peak of insolation, I'm hard pressed to come up with an explanation for it.

CT itself has reported it too, but it's not unprecedented or anything. 2007 saw increases of 1999 km2 (June 23rd) and 15,672 km2 (June 27th), for instance.
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ghoti

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Re: 2015 sea ice area and extent data
« Reply #504 on: June 25, 2015, 05:10:45 PM »
The delta map shows all of Lake Erie and Lake Ontario suddenly being completely ice covered. Seriously? They really have to fix that.

Nightvid Cole

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Re: 2015 sea ice area and extent data
« Reply #505 on: June 25, 2015, 05:57:23 PM »
OSISAF/MyOcean shows heavily reduced concentration now covering ~50% of the Arctic Ocean. How can CT not continue going further off the June cliff?




Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #506 on: June 25, 2015, 06:57:18 PM »
The Wed. Number (0.3) still looks like a glitch.  Given the current heat exchange, at the peak of insolation, I'm hard pressed to come up with an explanation for it.

CT itself has reported it too, but it's not unprecedented or anything. 2007 saw increases of 1999 km2 (June 23rd) and 15,672 km2 (June 27th), for instance.
Indeed. 2012 itself saw a drop of 56,420 (0.4630). It happens...

jdallen

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Re: 2015 sea ice area and extent data
« Reply #507 on: June 25, 2015, 07:02:14 PM »
The Wed. Number (0.3) still looks like a glitch.  Given the current heat exchange, at the peak of insolation, I'm hard pressed to come up with an explanation for it.

CT itself has reported it too, but it's not unprecedented or anything. 2007 saw increases of 1999 km2 (June 23rd) and 15,672 km2 (June 27th), for instance.
Indeed. 2012 itself saw a drop of 56,420 (0.4630). It happens...
Precidented or not, it's counter to the heat flow in a major way, and begs an explanation.
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sedziobs

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Re: 2015 sea ice area and extent data
« Reply #508 on: June 25, 2015, 07:10:38 PM »
Precidented or not, it's counter to the heat flow in a major way, and begs an explanation.

I see no reason to believe it's anything other than noise associated with remote sensing - the same reason why 5 day means are often used. 

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Re: 2015 sea ice area and extent data
« Reply #509 on: June 25, 2015, 07:59:01 PM »
My thoughts are it's combination of many factors a few of which are melt ponds draining through cracks and movement of ice between scanning borders which allows for ice to be potentially counted twice and cloud cover.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #510 on: June 26, 2015, 08:21:03 AM »
Looking at the day-to-day changes for the last three weeks, shows that the +0.3 glitch pales in comparison with the mega -340k "glitch" a week before. Explain that one before bothering with a point just a few k above several others that looks very much as the noise in the graph.

I would call neither a glitch, if it was so then a negative glitch would be followed by a return to normal: a positive spike. Likewise for a positive "glitch".


Lord M Vader

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Re: 2015 sea ice area and extent data
« Reply #511 on: June 26, 2015, 08:55:04 AM »
Morning guys!

I just found this interesting product with perhaps a daily calculation of the volume in the Arctic basin in combination with a estimated ice thickness. Have you seen it before? What kind of value does it have?

http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150625.png

This is another map of the modelled ice thickness including a forecast for the next 5 days. Of interest is only the Arctic Sea and to some degree Greenland. Unfortunely, the five last parameters don't work for the Arctic Sea.

http://ocean.dmi.dk/anim/index.uk.php

Most interesting is the forecast of the sea ice thickness around the North Pole which is foreseen to be less than 1,5 m by June 30....

Oh, finally a link to satellite images around Greenland including Nares Strait :)
http://ocean.dmi.dk/arctic/morrisjessup.uk.php

and a link to Greenland ice charts. http://ocean.dmi.dk/arctic/icecharts_gl_1.uk.php

Sincerely, LMV

wanderer

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Re: 2015 sea ice area and extent data
« Reply #512 on: June 26, 2015, 09:01:55 AM »
Day 173: CT area

2015: 8.12031 million sq. km
2012: 7.72807 million sq. km

Difference just about 400k

2015 is 200k behind in Baffin, 100k in Kara, these regions will melt out anyway and won't trigger or delay other melting, so actually we are (100k) close to 2012

Nevertheless, 2012-arcticseaice still looks weeker to me here:
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=06&fd=23&fy=2012&sm=06&sd=23&sy=2015

Here, 2015-arcticseaice seems to be (much!) weeker:
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticict/nowcast/ict2015062418_2015062500_040_arcticict.001.gif
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticict/nowcast/ict2012062418_2012062500_035_arcticict.001.gif
(But i think ice thickness was underestimated in 2013 and 2014 as well...)

jdallen

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Re: 2015 sea ice area and extent data
« Reply #513 on: June 26, 2015, 09:23:17 AM »
Looking at the day-to-day changes for the last three weeks, shows that the +0.3 glitch pales in comparison with the mega -340k "glitch" a week before. Explain that one before bothering with a point just a few k above several others that looks very much as the noise in the graph.

I would call neither a glitch, if it was so then a negative glitch would be followed by a return to normal: a positive spike. Likewise for a positive "glitch".
Can't argue with your logic; -340 is definitely glitchy as hell.

Can't say it necessarily makes 0.3 less or more glitchy, so I'll disagree with the notion I need to solve the -340 problem before the 0.3 problem.

It does point towards problems with the day-over-day sampling of extent and area.
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slow wing

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Re: 2015 sea ice area and extent data
« Reply #514 on: June 26, 2015, 09:34:04 AM »
Morning guys!

I just found this interesting product with perhaps a daily calculation of the volume in the Arctic basin in combination with a estimated ice thickness. Have you seen it before? What kind of value does it have?

http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150625.png

This is another map of the modelled ice thickness including a forecast for the next 5 days. Of interest is only the Arctic Sea and to some degree Greenland. Unfortunely, the five last parameters don't work for the Arctic Sea.

http://ocean.dmi.dk/anim/index.uk.php

Most interesting is the forecast of the sea ice thickness around the North Pole which is foreseen to be less than 1,5 m by June 30....

Oh, finally a link to satellite images around Greenland including Nares Strait :)
http://ocean.dmi.dk/arctic/morrisjessup.uk.php

and a link to Greenland ice charts. http://ocean.dmi.dk/arctic/icecharts_gl_1.uk.php

Sincerely, LMV
Nice find!
Maybe others are already familiar with it, but a daily updated ice thickness map is very interesting!

PS it says it uses the DMI HYCOM-CICE model. How is this related to the CICE model that is linked to Neven's graphs page & appears here:
http://www7320.nrlssc.navy.mil/hycomARC/arctic.html
?
« Last Edit: June 26, 2015, 11:24:57 AM by slow wing »

Jim Hunt

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Re: 2015 sea ice area and extent data
« Reply #515 on: June 26, 2015, 12:07:05 PM »
I just found this interesting product with perhaps a daily calculation of the volume in the Arctic basin in combination with a estimated ice thickness. Have you seen it before? What kind of value does it have?

The individual maps/graphs are available in larger format via the Polar Portal. See e.g.



This is probably not the sort of value you had in mind, but I used one of them to pull "Steve Goddard's" chain the other day:

Does a Lie Told Often Enough Become the Truth?

Regarding real value, then I suppose ongoing comparisons with ACNFS/PIOMAS are in order?
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

slow wing

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Re: 2015 sea ice area and extent data
« Reply #516 on: June 26, 2015, 12:49:22 PM »
Someone's plonked down a giant spade next to Greenland and scraped a furrow in the ice all the way to Siberia!

Jim Hunt

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Re: 2015 sea ice area and extent data
« Reply #517 on: June 26, 2015, 12:57:49 PM »
it says it uses the DMI HYCOM-CICE model. How is this related to the CICE model that is linked to Neven's graphs page?

DMI aren't very specific, but it sounds like much the same model with ECMWF instead of NAVGEM forcing. The CICE version number isn't mentioned either. Version 5 is now out there, but ACNFS/GOFS still use version 4 as far as I am aware.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #518 on: June 26, 2015, 01:21:11 PM »
ADS-NIPR Extent:
9,883,311 km2 (25 June)
Down 4,058,749 km2 (29.11%) from 2015 maximum of 13,942,060 km2 on 15 February.
6,705,856 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 33,495 km2 from previous day.
Down 227,522 km2 over past seven days (daily average: -32,503 km2).
Down 995,260 km2 for the month of June (daily average: -39,810 km2).
392,371 km2 below 2000s average for this date.
197,606 km2 above 2010s average for this date.
191,982 km2 above 2014 value for this date.
389,614 km2 above 2012 value for this date.
3rd lowest June to-date average.
6th lowest value for the date.
64 days this year (36.36% year-to-date) have recorded the lowest daily extent.
32 days (18.18%) have recorded the second lowest.
32 days (18.18%) have recorded the third lowest.
128 days (72.73%) in total have been among the three lowest on record.

Falling further and further behind:



CT Area:
NOTE: due to the absence of official CT sea ice area data, I've instead used Wipneus' calculated area numbers for Days 0.4767 - 0.4795. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
7,957,204 km2 (25 June [Day 0.4795])
Down 5,317,351 km2 (40.06%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
5,723,195 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 70,640 km2 from previous day.
Down 563,102 km2 over past seven days (daily average: -80,443 km2).
Down 2,179,377 km2 for the month of June (daily average: -87,175 km2).
433,249 km2 below 2000s average for this date.
159,374 km2 above 2010s average for this date.
60,690 km2 below 2014 value for this date.
585,975 km2 above 2012 value for this date.
7th lowest June to-date average.
6th lowest value for the date.
7 days this year (3.98% year-to-date) have recorded the lowest daily area.
19 days (10.8%) have recorded the second lowest.
29 days (16.48%) have recorded the third lowest.
55 days in total (31.25%) have been among the lowest three on record.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #519 on: June 26, 2015, 04:29:36 PM »
From today's NSIDC data update I calculate the following CT updates (by day that CT "normally" reports, starting with the day of the last day that CT updated its data):

Wed       8.120306
Thu -92.5  8.027844
Fri -70.6  7.957204
Sat -123.7  7.833457
Sun -45.5  7.787915

That is with help from the "lake ice" dropping -10k. Other regions that declined are CAB (-22k3), Beaufort (-15k5), Greenland Sea (-13k5)  and Hudson (-13k1). Area increases in Laptev (+25k5) and CAA (+12k2).
In the attached delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up)

Tor Bejnar

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Re: 2015 sea ice area and extent data
« Reply #520 on: June 26, 2015, 05:22:33 PM »
I really appreciate your adding the pinks and light blues, Wipneus.  It gives a sense of 'trending'.  Thanks!
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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #521 on: June 27, 2015, 04:25:54 PM »
From today's NSIDC data update I calculate the following CT updates (by day that CT "normally" reports, starting with the day of the last day that CT updated its data):

Wed       8.120306
Thu -92.5  8.027844
Fri -70.6  7.957204
Sat -123.7  7.833457
Sun -45.5  7.787983
Mon -79.3  7.708670

Declines in the CAB (-56k), Hudson (-27k) and Kara (-15k2). Area increases inCAA (+13k3) and ESS (+12k2).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #522 on: June 28, 2015, 03:12:57 PM »
ADS-NIPR Extent:
9,731,983 km2 (27 June)
Down 4,210,077 km2 (30.2%) from 2015 maximum of 13,942,060 km2 on 15 February.
6,554,528 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 85,736 km2 from previous day.
Down 354,982 km2 over past seven days (daily average: -50,712 km2).
Down 1,146,588 km2 for the month of June (daily average: -42,466 km2).
409,126 km2 below 2000s average for this date.
237,313 km2 above 2010s average for this date.
224,853 km2 above 2014 value for this date.
395,909 km2 above 2012 value for this date.
3rd lowest June to-date average.
6th lowest value for the date.
64 days this year (35.96% year-to-date) have recorded the lowest daily extent.
32 days (17.98%) have recorded the second lowest.
32 days (17.98%) have recorded the third lowest.
128 days (71.91%) in total have been among the three lowest on record.


CT Area:
7,787,654 km2 (27 June [Day 0.485])
Down 5,486,901 km2 (41.33%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
5,553,645 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 45,791 km2 from previous day.
Down 549,843 km2 over past seven days (daily average: -78,549 km2).
Down 2,348,926 km2 for the month of June (daily average: -86,997 km2).
375,231 km2 below 2000s average for this date.
236,417 km2 above 2010s average for this date.
64,977 km2 below 2014 value for this date.
675,500 km2 above 2012 value for this date.
6th lowest June to-date average.
7th lowest value for the date.
7 days this year (3.93% year-to-date) have recorded the lowest daily area.
19 days (10.67%) have recorded the second lowest.
29 days (16.29%) have recorded the third lowest.
55 days in total (30.9%) have been among the lowest three on record.




Wipneus

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Re: 2015 sea ice area and extent data
« Reply #523 on: June 28, 2015, 05:00:39 PM »
From today's NSIDC data update I calculate the following CT updates (by day that CT "normally" reports, starting with the day of the last day that CT updated its data):

Sun       7.787654
Mon -79.8  7.707865
Tue -144.1  7.563812

Perhaps we are in for a late June cliff. Biggest decline is the CAB (-70k5) but I think the most impressive is Laptev at -67k7. With Beaufort (-18k6) , the Basin is in solid decline.

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

BornFromTheVoid

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Re: 2015 sea ice area and extent data
« Reply #524 on: June 28, 2015, 07:17:33 PM »
Update for the week to June 28th

The current 5 day mean is on 10,413,200km2 while the 1 day extent is at 10,280,000km2.
The daily anomaly (compared to 81-10) is at -831,290km2, a decrease from -887,150km2 last week. The anomaly compared to the 07, 11 and 12 average is at +299,000km2, an increase from +98,467km2 last week. We're currently 7th lowest on record, down from 4th last week.



The average daily change over the last 7 days was -52.5k/day, compared to the long term average of -60.5k/day, and the 07, 11 and 12 average of -81.1k/day.
The average long term change over the next week is -85.2k/day, with the 07, 11, and 12 average being -124.6k/day.



The loss so far this June is the 18th largest on record. To achieve the largest monthly drop, a daily loss of at least 503.9k/day is required, while the smallest drop requires an increase of at least than 105.6k/day and an average drop requires a loss of 95.5k/day.


Wipneus

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Re: 2015 sea ice area and extent data
« Reply #525 on: June 29, 2015, 04:31:09 PM »
From today's NSIDC data update I calculate the following CT updates (by day that CT "normally" reports, starting with the day of the last day that CT updated its data):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.4  7.455033

Wednesday would not be a century without the help of "lake ice" (-16k). Biggest declines were Hudson (-44k5), CAB (-29k2), Baffin (-20k6) and Kara (-18k1). Ice are grew in Beaufort (+21k) and Laptev (+19k1).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

jdallen

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Re: 2015 sea ice area and extent data
« Reply #526 on: June 29, 2015, 05:34:46 PM »
Let see if I've got this right. By wipneus' numbers, June 25 through 30 inclusive, the ice has/will decline 540k KM2, or an average of about 90K per day.

Wednesday starts July off with a century break, after which it looks like the weather gets worse.

So, what does the ice outlook appear to be if we lose 3 million KM2 in July? How probable would that be?
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oren

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Re: 2015 sea ice area and extent data
« Reply #527 on: June 29, 2015, 05:36:33 PM »
It seems Hudson is finally giving way. It held up remarkably well until now.

Tor Bejnar

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Re: 2015 sea ice area and extent data
« Reply #528 on: June 29, 2015, 06:03:29 PM »
jdallen,
When you write "it looks like the weather gets worse", it not obvious whether you mean 'worse for ice' or 'worse for beast'.  One may mean sunny skies; the other (traditionally), snow and cold wind [].  (In the long run, or course, melted ice is not good for the current assemblage of mammals that wander in the Arctic.)

From context, I think you mean 'worse for ice'.

This imprecision is a recurring problem in this forum; I'm sure I do it too.
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Re: 2015 sea ice area and extent data
« Reply #529 on: June 29, 2015, 06:28:26 PM »
Quote
This imprecision is a recurring problem in this forum

It is also, unfortunately, a problem with the English language.....AND.....a problem with humans in general (we ALWAYS know what WE mean.....and don't understand why other people don't understand US:)

That is one of the reasons the US has SOOOOO many lawyers (imprecise English language, and imprecise humans that don't communicate CLEARLY).  We ALL do it.....unfortunately.

FOX (RT) News....."The Trump Channel.....where truth and journalism are dead."

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Re: 2015 sea ice area and extent data
« Reply #530 on: June 29, 2015, 10:46:47 PM »
We ALL do it.....unfortunately.

Not true. Obviously, the last few post talk about how the clear humans wandering the arctic are made of ice from beasts.   
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DavidR

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Re: 2015 sea ice area and extent data
« Reply #531 on: June 29, 2015, 11:15:33 PM »
Let see if I've got this right. By wipneus' numbers, June 25 through 30 inclusive, the ice has/will decline 540k KM2, or an average of about 90K per day.

Wednesday starts July off with a century break, after which it looks like the weather gets worse.

So, what does the ice outlook appear to be if we lose 3 million KM2 in July? How probable would that be?
jda,
you  are forgetting thay Wipneus' figures are 'day released', not 'day measured'  Wed in this case means measured on Sunday (28th).
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jdallen

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Re: 2015 sea ice area and extent data
« Reply #532 on: June 30, 2015, 04:45:26 AM »

From context, I think you mean 'worse for ice'.

This imprecision is a recurring problem in this forum; I'm sure I do it too.
Sorry - it is something I've also noticed and normally attempt to stay ahead of, at the risk of being pedantic.

Thank you for the criticism.
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Re: 2015 sea ice area and extent data
« Reply #533 on: June 30, 2015, 04:50:33 AM »
Let see if I've got this right. By wipneus' numbers, June 25 through 30 inclusive, the ice has/will decline 540k KM2, or an average of about 90K per day.

Wednesday starts July off with a century break, after which it looks like the weather gets worse.

So, what does the ice outlook appear to be if we lose 3 million KM2 in July? How probable would that be?
jda,
you  are forgetting thay Wipneus' figures are 'day released', not 'day measured'  Wed in this case means measured on Sunday (28th).

Hmmm.  Suggests the cascade off of the cliff is even steeper, which in context of the weather, makes sense.

My over all point is, in spite of perceptions that somehow, 2015 wasn't keeping up with the lowest three years, weather *is* pushing melt hard, even if has not followed arbitrary human perceptions of timing.
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Re: 2015 sea ice area and extent data
« Reply #534 on: June 30, 2015, 12:49:22 PM »
Let see if I've got this right. By wipneus' numbers, June 25 through 30 inclusive, the ice has/will decline 540k KM2, or an average of about 90K per day.

Wednesday starts July off with a century break, after which it looks like the weather gets worse.

So, what does the ice outlook appear to be if we lose 3 million KM2 in July? How probable would that be?

Losing 3 million km2 of area in July isn't unprecedented; it happened in both 2007 and 2009 (and 2013 came close with a decrease of 2.89 million). But losing 3 million this year would give SIA a month-ending value of 4.5 million km2, which would still leave 2015 in 5th place behind 2012, 2011, 2007, and 2010. (To begin August in the top three, July would have to see more than 3.2 million km2 of area disappear, and that's never happened.)

In short: time is running out for the 2015 SIA minimum to even crack the top three years on record. That's not to say it can't or won't happen; July and August weather can cause wild swings either way. We could see a GAC event like in 2012 that eats ice by the gigaton. Or we could see a ten-day period at the end of July like we did in 2013 where area actually grew by 20k km2.

Ah, the fun of watching the ice... :)

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Re: 2015 sea ice area and extent data
« Reply #535 on: June 30, 2015, 03:09:40 PM »
DMI aren't very specific, but it sounds like much the same model with ECMWF instead of NAVGEM forcing

I've now received some additional information from DMI:

Quote
Our operational model system consists of the HYCOM version 2.2.55 and CICE version 4.0 models, coupled using the ESMF coupler. The model resolution is about 10 km, and the domain covers the Arctic Ocean and the Atlantic Ocean to approximately 20°S. We currently use ECMWF operational atmospheric forcing, and the model assimilates OSISAF reanalysed sea ice concentration and GHRSST Level 4 DMI_OI sea surface temperatures.

There's a publicly available description of the operational model setup here: http://ocean.dmi.dk/models/hycom.uk.php

We can be contacted through this page: http://www.dmi.dk/en/about/dmi-online/contact-dmi/
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Re: 2015 sea ice area and extent data
« Reply #536 on: June 30, 2015, 05:10:16 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.8  7.454602
Thu -34.0  7.420578

That would have been only -26k without the "lake ice". There were declines in Barents (-14k) and Baffin (-12k). Area increased in the CAB (+23k1) and Kara (+12k8).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #537 on: June 30, 2015, 07:04:40 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.8  7.454602
Thu -34.0  7.420578


And the painfully slow melt continues. These numbers will drop 2015 back to 8th place, behind 2012, 2010, 2011, 2007, 2013, 2014, and 2008. In fact, the difference between 2012 and this year will be over 800,000 km2, the widest gap so far this year. 2015 has struggled to put together any extended strings of consecutive century breaks, and failed.

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Re: 2015 sea ice area and extent data
« Reply #538 on: June 30, 2015, 07:13:58 PM »
It should be noted from the Regional Graphs page that area is comparatively low in the CAB and Chukchi; high in Hudson, Baffin and Barents; and mixed in the other seas.  In the areas where melt is lagging, we would still expect a complete melt in the next month.

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Re: 2015 sea ice area and extent data
« Reply #539 on: June 30, 2015, 10:13:25 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.8  7.454602
Thu -34.0  7.420578


And the painfully slow melt continues. These numbers will drop 2015 back to 8th place, behind 2012, 2010, 2011, 2007, 2013, 2014, and 2008. In fact, the difference between 2012 and this year will be over 800,000 km2, the widest gap so far this year. 2015 has struggled to put together any extended strings of consecutive century breaks, and failed.

The numbers are what you say, but they make utterly no sense.  Weather *absolutely* is better for melt than 2013 and 2014.  More heat is entering the arctic, yet here we are.
« Last Edit: July 01, 2015, 06:53:34 AM by jdallen »
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Re: 2015 sea ice area and extent data
« Reply #540 on: July 01, 2015, 06:25:04 AM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.8  7.454602
Thu -34.0  7.420578


And the painfully slow melt continues. These numbers will drop 2015 back to 8th place, behind 2012, 2010, 2011, 2007, 2013, 2014, and 2008. In fact, the difference between 2012 and this year will be over 800,000 km2, the widest gap so far this year. 2015 has struggled to put together any extended strings of consecutive century breaks, and failed.

Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?



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Re: 2015 sea ice area and extent data
« Reply #541 on: July 01, 2015, 07:01:28 AM »

Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?
Technically correct. But from my observation in this forum it is a shortcut to describing decreases. That would include, melting, exporting, compaction and any other reason for that decrease. From there we then go and sometimes discuss Why the decrease. True melt is always part of the equation, but almost always only a part. Example: decreases in September rarely have to do with melting, Sometimes export, more often compaction.
Where 'melt' also gets involved in is the thinning of the ice.
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Re: 2015 sea ice area and extent data
« Reply #542 on: July 01, 2015, 01:50:14 PM »
Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?

Of course not. But in the popular press, the term "melt" is used most often when talking about the Arctic sea ice disappearing, so I too--as a non-professional scientist--most often use the term "melt" as shorthand for all forms of ice decrease for the sake of brevity. Most laypeople read of the Arctic sea ice "melting"; they neither know nor care about compaction, or sublimation, or export. So when I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that I'm referring to all manner of sea ice extent and area decrease.

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Re: 2015 sea ice area and extent data
« Reply #543 on: July 01, 2015, 03:28:46 PM »
ADS-NIPR Extent:
9,482,316 km2 (30 June)
Down 4,459,744 km2 (31.99%) from 2015 maximum of 13,942,060 km2 on 15 February.
6,304,861 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 59,822 km2 from previous day.
Down 482,568 km2 over past seven days (daily average: -68,938 km2).
Down 1,396,255 km2 for the month of June (daily average: -46,542 km2).
423,885 km2 below 2000s average for this date.
287,281 km2 above 2010s average for this date.
424,759 km2 above 2014 value for this date.
442,405 km2 above 2012 value for this date.
4th lowest June average.
7th lowest value for the date.
64 days this year (35.36% year-to-date) have recorded the lowest daily extent.
32 days (17.68%) have recorded the second lowest.
32 days (17.68%) have recorded the third lowest.
128 days (70.72%) in total have been among the three lowest on record.


CT Area:
7,454,821 km2 (30 June [Day 0.4932])
Down 5,819,735 km2 (43.84%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
5,220,811 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 109,291 km2 from previous day.
Down 665,485 km2 over past seven days (daily average: -95,069 km2).
Down 2,681,760 km2 for the month of June (daily average: -89,392 km2).
453,410 km2 below 2000s average for this date.
237,587 km2 above 2010s average for this date.
84,658 km2 below 2014 value for this date.
725,730 km2 above 2012 value for this date.
7th lowest June average.
5th lowest value for the date.
7 days this year (3.87% year-to-date) have recorded the lowest daily area.
19 days (10.5%) have recorded the second lowest.
29 days (16.02%) have recorded the third lowest.
55 days in total (30.39%) have been among the lowest three on record.

epiphyte

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Re: 2015 sea ice area and extent data
« Reply #544 on: July 01, 2015, 09:05:06 PM »
Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?

Of course not. But in the popular press, the term "melt" is used most often when talking about the Arctic sea ice disappearing, so I too--as a non-professional scientist--most often use the term "melt" as shorthand for all forms of ice decrease for the sake of brevity. Most laypeople read of the Arctic sea ice "melting"; they neither know nor care about compaction, or sublimation, or export. So when I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that I'm referring to all manner of sea ice extent and area decrease.

Understood - but if everyone uses the word "melt" as a proxy for decreases in area and/or extent, then it closes people's minds to the possibility that there can be aggressive melt (i.e. reduction in volume) occurring without changing the extent much at all.

Conversely, if the extent were to drop off a huge cliff sometime soon, which IMO is quite probable, it would not be because all the ice that was there in April melted at once.

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Re: 2015 sea ice area and extent data
« Reply #545 on: July 01, 2015, 10:48:05 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       7.707334
Tue -143.9  7.563430
Wed -108.8  7.454602
Thu -34.0  7.420578


And the painfully slow melt continues. These numbers will drop 2015 back to 8th place, behind 2012, 2010, 2011, 2007, 2013, 2014, and 2008. In fact, the difference between 2012 and this year will be over 800,000 km2, the widest gap so far this year. 2015 has struggled to put together any extended strings of consecutive century breaks, and failed.

The numbers are what you say, but they make utterly no sense.  Weather *absolutely* is better for melt than 2013 and 2014.  More heat is entering the arctic, yet here we are.

2007 to 2012 summers were dominated by a dipole, low over coastal Siberia, high over the Arctic ice pack and Greenland. The Greenland high increased export through Fram, the dipole between the Arctic Ocean and Siberia drew in warm Pacific air. This state has not developed so far this year, all we have had is fleeting occurences of daily patterns that could have developed into a 2007 to 2012 type dipole pattern but didn't. In the first half of June a strong dipole between a low centred on Barents and the Greenland high developed, it kept Greenland sea area up - a sign of strong export. Since about 14 June vector winds over the Fram Strait have been normal and Greenland sea export has faltered leading to a decrease in area similar to the climatological mean loss.

Yes, this year is warm, yes conditions for melt are better than 2013 /2014. But because of the large scale synoptic pattern and lack of the 2007 to 2012 dipole type pattern, prospects for a melt towards the lowest of the 2007 to 2012 years is poor. Something around the median of the range of 2007 to 2012 years is the most likely outcome for September.

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Re: 2015 sea ice area and extent data
« Reply #546 on: July 01, 2015, 11:07:36 PM »
Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?

Of course not. But in the popular press, the term "melt" is used most often when talking about the Arctic sea ice disappearing, so I too--as a non-professional scientist--most often use the term "melt" as shorthand for all forms of ice decrease for the sake of brevity. Most laypeople read of the Arctic sea ice "melting"; they neither know nor care about compaction, or sublimation, or export. So when I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that I'm referring to all manner of sea ice extent and area decrease.

Understood - but if everyone uses the word "melt" as a proxy for decreases in area and/or extent, then it closes people's minds to the possibility that there can be aggressive melt (i.e. reduction in volume) occurring without changing the extent much at all.

Conversely, if the extent were to drop off a huge cliff sometime soon, which IMO is quite probable, it would not be because all the ice that was there in April melted at once.

Again: "[W]hen I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that I'm referring to all manner of sea ice extent and area decrease." I seriously doubt that I'm closing anyone's mind to "...the possibility that there can be aggressive melt". I'm just just employing a well-understood, widely-used shorthand term for ice loss without actually repeating the terms "loss" or "decrease" a dozen times in each sentence.

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Re: 2015 sea ice area and extent data
« Reply #547 on: July 02, 2015, 08:21:58 AM »
From yesterday's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):
Wed       7.454821
Thu -34.3  7.420529
Fri -139.8  7.280707

Biggest declines outside the Basin in Baffin (-42k), Hudson (-25k5) and Kara (-14k1). Within the Basin ESS dropped -25k1.

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Note: due to computer problems (the local heatwave seems to affect the aging silicon or something) this message came to you with a delay. This may last for some time until I have wired up another computer, affecting my other regular forum activities (PIOMAS and "Home Brew") as well. Cooler weather is expected this Sunday.

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Re: 2015 sea ice area and extent data
« Reply #548 on: July 02, 2015, 09:06:04 AM »
Melt is not, not, not, the same thing as decrease in extent.
Melt is not, not, not the same thing as decrease in area.

Does anyone seriously dispute that?

Of course not. But in the popular press, the term "melt" is used most often when talking about the Arctic sea ice disappearing, so I too--as a non-professional scientist--most often use the term "melt" as shorthand for all forms of ice decrease for the sake of brevity. Most laypeople read of the Arctic sea ice "melting"; they neither know nor care about compaction, or sublimation, or export. So when I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that I'm referring to all manner of sea ice extent and area decrease.

Understood - but if everyone uses the word "melt" as a proxy for decreases in area and/or extent, then it closes people's minds to the possibility that there can be aggressive melt (i.e. reduction in volume) occurring without changing the extent much at all.

Conversely, if the extent were to drop off a huge cliff sometime soon, which IMO is quite probable, it would not be because all the ice that was there in April melted at once.

Again: "[W]hen I write something here such as "the painfully slow melt continues", I'm trusting that everyone reading it is knowledgeable enough to understand that [...]


Bad idea. If you say  "the painfully slow melt continues" [...]   ,under the assumption that others can be relied upon to translate what you say into what you mean,  the only thing you can be sure of is that someone else will pick up on what you said, attribute to you it's literal meaning, and then hang it around your neck.

...and again. "all manner of sea ice extent and area decrease"  is not synonymous with "melt". The two aren't totally independent, but they are far from in lockstep with each other.


 




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Re: 2015 sea ice area and extent data
« Reply #549 on: July 02, 2015, 09:56:02 AM »
Note: due to computer problems (the local heatwave seems to affect the aging silicon or something) this message came to you with a delay. This may last for some time until I have wired up another computer, affecting my other regular forum activities (PIOMAS and "Home Brew") as well. Cooler weather is expected this Sunday.

Hang in there, Wip! The 'ellende' has just started in Austria as well.

Quote
Bad idea. If you say  "the painfully slow melt continues" [...]   ,under the assumption that others can be relied upon to translate what you say into what you mean,  the only thing you can be sure of is that someone else will pick up on what you said, attribute to you it's literal meaning, and then hang it around your neck.

I don't agree. In that case we may all as well stop writing. Most people know what is meant with 'melt' in this context. If they don't, you explain. I get this all the time with the "good/bad weather stuff", and I'm glad it pops up, because it offers me the chance to espouse my views about good and bad wrt Arctic sea ice loss.
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