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Neven

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Re: 2015 sea ice area and extent data
« Reply #700 on: July 20, 2015, 05:42:29 PM »
July 2015 saw 14 century breaks in 20 days. 2013 comes close with 13 century breaks, but in my spreadsheet all the other years in the 2006-2015 period saw 11 century breaks or less. 2012, for instance, saw 8 century breaks.
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Andir

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Re: 2015 sea ice area and extent data
« Reply #701 on: July 20, 2015, 06:20:21 PM »
I think in two or three days the hudson/ baffin effect  will be over. Is there another "delayed melt effect this year or will the melt numbers will slow down a bit?

jdallen

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Re: 2015 sea ice area and extent data
« Reply #702 on: July 20, 2015, 06:25:05 PM »
I think in two or three days the hudson/ baffin effect  will be over. Is there another "delayed melt effect this year or will the melt numbers will slow down a bit?
Good question. It depends on the state of the remaining ice.  To that point, there are huge areas of very vulnerable ice - near or over 2 million km2 - outside of the CAB. 

It may slow down, but that slowdown might be a drop from 125,000 km2 a day to 100,000 km2 a day...
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jai mitchell

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Re: 2015 sea ice area and extent data
« Reply #703 on: July 20, 2015, 07:04:10 PM »
or it might speed up.
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Re: 2015 sea ice area and extent data
« Reply #704 on: July 20, 2015, 09:23:25 PM »
Mea Culpa Time!!

It's never fun to admit having made a substantial mistake, particularly when it is in something you have made public.  When I first built my SIE models last spring, somehow I erroneously entered the wrong value for the Record MAX Loss for the latter half of August, by an amount in excess of ~400K. Therefore, my charts and tables wrongly indicated that there was some small chance of catching 2012 values this year.  My apologies to everyone for the mistake. Please note that any plots or results using average values for each period were correct. I'll assign the mistake to one of the following:

Partial vision in one eye
Attention Deficit Disorder
Lack of due diligence
The aging process
 
Here are corrected versions of both the chart and the table.



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oren

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Re: 2015 sea ice area and extent data
« Reply #705 on: July 21, 2015, 01:54:57 AM »

We are beginning to get obsessed with semantics.  What may be "exceptional" or "remarkable" to one person may be mundane to someone else.  We should remember that for many members of this Forum, English is a second or third language.  Even among native English speakers there are significant semantic differences between countries and regions within a given country.  I found  this to be true when I had the opportunities to work with the British and Australian navies.

I have the utmost respect for the massive efforts Wipneus has made to both the Forum and the Blog.  His charts, graphs and animations have been "Exceptionally" valuable learning tools for each of us.  His choice of adjectives and adverbs is entirely up to him.

This thread is not about "Scientific Technical Writing 101"

Thank you!

TeaPotty

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Re: 2015 sea ice area and extent data
« Reply #706 on: July 21, 2015, 02:22:56 AM »
I just want to chime in and also thank the tireless Wipneus  ;D

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Re: 2015 sea ice area and extent data
« Reply #707 on: July 21, 2015, 03:52:23 AM »
Quote
I have no idea what criteria you are using to make the current rate of area decrease stand out as in any way exceptional.

So in English the words remarkable and exceptional are synonymous? Perhaps it is my simple English but that is not what is meant.

Wipneus, your use of the word remarkable is entirely correct: it means, "worthy of attention."

Edit: Catching up on more recent messages, I see this point has perhaps already been made.

P.S. I am a native english speaker.

P.P.S. You rock! :)
« Last Edit: July 21, 2015, 04:02:05 AM by greatdying2 »
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

greatdying2

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Re: 2015 sea ice area and extent data
« Reply #708 on: July 21, 2015, 04:19:47 AM »
I think in two or three days the hudson/ baffin effect  will be over. Is there another "delayed melt effect this year or will the melt numbers will slow down a bit?
Good question. It depends on the state of the remaining ice.  To that point, there are huge areas of very vulnerable ice - near or over 2 million km2 - outside of the CAB. 

It may slow down, but that slowdown might be a drop from 125,000 km2 a day to 100,000 km2 a day...

Hudson and Baffin combined have about 400 km2 area remaining, and a bit more than that in extent. If this all goes within 2-3 days, they'll be amazing days! To me it looks more like, if the current rates of decline continue, yes perhaps Hudson will be gone within a few days but Baffin will last for a couple more weeks.

I nevertheless agree with what I think is perhaps your underlying message: that these areas were always going to completely melt out (albeit late, throwing all kinds of wrenches in comparisons of overall melt amounts for particular time periods...). What actually matters is better represented for example in the following graphs, which suggest that like 2012, this year may be starting to diverge from the last two years in area and extent measures (thanks yet again to Wipneus). The next couple of weeks will be key, and it seems the weather this week at least is forecast to be conducive to higher than normal reductions.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png
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.

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Re: 2015 sea ice area and extent data
« Reply #709 on: July 21, 2015, 07:54:48 AM »
Thank you for wipneus links. And you are right. There are still 400 km2 remaining in Hudson/baffin area. But if u look to former years, the last 100 km2 for each region disapearing slowly with some rebounds. So i think, we can only see max. 200 km2 of fast melt. Perhaps it will take longer for baffin, so the effect gets even smaller the next days for these regions.

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #710 on: July 21, 2015, 02:09:38 PM »
ADS-NIPR Extent:
7,522,508 km2 (20 July)
Down 6,419,552 km2 (46.04%) from 2015 maximum of 13,942,060 km2 on 15 February.
4,345,053 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 139,308 km2 from previous day.
Down 813,073 km2 over past seven days (daily average: -116,153 km2).
Down 1,959,808 km2 for the month of July (daily average: -97,990 km2).
713,856 km2 below 2000s average for this date.
177,611 km2 above 2010s average for this date.
32,792 km2 above 2014 value for this date.
365,712 km2 above 2012 value for this date.
8th lowest July to-date average.
6th lowest value for the date.
64 days this year (31.84% year-to-date) have recorded the lowest daily extent.
32 days (15.92%) have recorded the second lowest.
32 days (15.92%) have recorded the third lowest.
128 days (63.68%) in total have been among the three lowest on record.


CT Area:
NOTE: due to inconsistent updates of official CT sea ice area data, I'll be using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
5,193,609 km2 (21 July [Day 0.5507])
Down 8,080,946 km2 (60.88%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,959,600 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 115,637 km2 from previous day.
Down 744,071 km2 over past seven days (daily average: -106,296 km2).
Down 2,261,212 km2 for the month of July (daily average: -107,677 km2).
713,438 km2 below 2000s average for this date.
52,892 km2 above 2010s average for this date.
256,384 km2 below 2014 value for this date.
535,762 km2 above 2012 value for this date.
5th lowest July to-date average.
4th lowest value for the date.
7 days this year (3.47% year-to-date) have recorded the lowest daily area.
19 days (9.41%) have recorded the second lowest.
29 days (14.36%) have recorded the third lowest.
55 days in total (27.23%) have been among the lowest three on record.

Vergent

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Re: 2015 sea ice area and extent data
« Reply #711 on: July 21, 2015, 04:02:27 PM »

NSIDC Daily Extent:

2015,    07,  14,      8.746,
2015,    07,  15,      8.615,   -131k   
2015,    07,  16,      8.403,   -212k
2015,    07,  17,      8.271,   -132k
2015,    07,  18,      8.120,   -151k
2015,    07,  19,      7.932,   -188k
2015,    07,  20,      7.903,   - 29k

6 day loss: 843K, averaging -140/day.

For reference 2012:

2012,    07,  14,      7.868..............2015,    07,  14,      8.746, ...................+878k   
2012,    07,  15,      7.705,  -163k....2015,    07,  15,      8.615,   -131k
2012,    07,  16,      7.606,   -99k.....2015,    07,  16,      8.403,   -212k
2012,    07,  17,      7.481,  -125k....2015,    07,  17,      8.271,   -132k
2012,    07,  18,      7.420,   -61k.....2015,    07,  18,      8.120,   -151k
2012,    07,  19,      7.350,   -70k.....2015,    07,  19,      7.932,   -188k..........+582k
2012,    07,  20,      7.340,   -10k.....2015,    07,  20,      7.903,   - 29k...........+563k
2012,    07,  21,      7.297,  -113k
2012,    07,  22,      7.184,  -113k
2012,    07,  23,      7.118,   -66k
2012,    07,  24,      7.035,   -83k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg


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Re: 2015 sea ice area and extent data
« Reply #712 on: July 21, 2015, 04:15:40 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):

Sun       5.491770
Mon -93.7  5.398043
Tue -88.8  5.309246
Wed -115.6  5.193628
Thu -47.1  5.146514

The lower decline on Thursday has the support of ESS (-20k8), CAB (-18k7). Laptev (-11k7) and CAA (-10k8).
Hudson that showed some huge declines in the last few days slightly rebounded (+8k7), even more by extent (calculated as NSIDC calculates it) of +20k4.

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).

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Re: 2015 sea ice area and extent data
« Reply #713 on: July 22, 2015, 12:47:35 PM »
CT replaced the image with the date "2015-07-18" (not sure about the corresponding ice date) with a serious defect, quickly by another with corrected ice concentrations.

Vergent

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Re: 2015 sea ice area and extent data
« Reply #714 on: July 22, 2015, 04:06:16 PM »
NSIDC Daily Extent:



2012,    07,  14,      7.868..............2015,    07,  14,      8.746, ...................+878k   
2012,    07,  15,      7.705,  -163k....2015,    07,  15,      8.615,   -131k
2012,    07,  16,      7.606,   -99k.....2015,    07,  16,      8.403,   -212k
2012,    07,  17,      7.481,  -125k....2015,    07,  17,      8.271,   -132k
2012,    07,  18,      7.420,   -61k.....2015,    07,  18,      8.120,   -151k
2012,    07,  19,      7.350,   -70k.....2015,    07,  19,      7.932,   -188k..........+582k
2012,    07,  20,      7.340,   -10k.....2015,    07,  20,      7.903,   - 29k...........+563k
2012,    07,  21,      7.297,  -113k....2015,    07,  21,      7.807,   - 96k...........+580k
2012,    07,  22,      7.184,  -113k
2012,    07,  23,      7.118,   -66k
2012,    07,  24,      7.035,   -83k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #715 on: July 22, 2015, 04:15:48 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):

Sun       5.491770
Mon -93.7  5.398043
Tue -88.8  5.309246
Wed -115.6  5.193628
Thu -46.9  5.146720
Fri -73.6  5.073109

Friday's -73.6 has been offset by a +20k6 bump in "lake ice". It did not affect NSIDC extent as they do not include lake ice. The regions that showed most of the area decline are ESS (-26k4), CAB (-16k1), Kara (-10k9) and Beaufort (-10k2). Of those Beaufort saw an increase in extent (calculated as NSIDC calculates extent) of +11k3.

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).

greatdying2

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Re: 2015 sea ice area and extent data
« Reply #716 on: July 22, 2015, 04:37:43 PM »
The regions that showed most of the area decline are ESS (-26k4), CAB (-16k1), Kara (-10k9) and Beaufort (-10k2). Of those Beaufort saw an increase in extent (calculated as NSIDC calculates extent) of +11k3.
So Beaufort is spreading out even more and the ice edge is being pushed outwards, towards the warm Mackenzie river outflow.
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.

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Re: 2015 sea ice area and extent data
« Reply #717 on: July 22, 2015, 04:52:07 PM »
The regions that showed most of the area decline are ESS (-26k4), CAB (-16k1), Kara (-10k9) and Beaufort (-10k2). Of those Beaufort saw an increase in extent (calculated as NSIDC calculates extent) of +11k3.
So Beaufort is spreading out even more and the ice edge is being pushed outwards, towards the warm Mackenzie river outflow.

I'd be not so sure about that, having been set clockwise rotation. We'll see next couple of days.

If low pressure system over Beaufort is confirmed later in a few days, what you say might happen.

Which does not mean the ice is going to melt right away.

No matter what, more MYI is slowly creeping in into the region from the CAA right now if the drift maps of the ASIG are to be trusted.

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Re: 2015 sea ice area and extent data
« Reply #718 on: July 22, 2015, 06:00:37 PM »
Which does not mean the ice is going to melt right away.
Of course, but I guess the Mackenzie will be dumping heat into the ocean for many more weeks, well beyond the period when insolation has much impact.
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.

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Re: 2015 sea ice area and extent data
« Reply #719 on: July 22, 2015, 06:48:49 PM »
Which does not mean the ice is going to melt right away.
Of course, but I guess the Mackenzie will be dumping heat into the ocean for many more weeks, well beyond the period when insolation has much impact.

Much of the ice will eventually melt, but I'd have said "all the ice" a week ago. I am starting to lean to the side that maybe some Beaufort MYI might survive the season.

To follow up with the floe I talked about yesterday (first pic), a second pic from today's Uni Hamburg AMSR2 images (courtesy of Wipneus who generates these images). It is very close to the river delta, still its area evolves very slowly day after day, in waters supposed to be 4ºC plus (my estimate was 6ºC)

« Last Edit: July 22, 2015, 06:55:37 PM by seaicesailor »

Tor Bejnar

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Re: 2015 sea ice area and extent data
« Reply #720 on: July 22, 2015, 07:18:18 PM »
If (some of) the large remaining floes in the Beaufort Sea are genuine old fashioned multiyear ice (MYI), they might be 5 or 10 m thick and not be honeycombed ("rotten") yet.  It will take a while for them to melt, even in 'warm' water.  Think Boston's pile of snow in June.
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Neven

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Re: 2015 sea ice area and extent data
« Reply #722 on: July 22, 2015, 07:41:25 PM »

Much of the ice will eventually melt, but I'd have said "all the ice" a week ago. I am starting to lean to the side that maybe some Beaufort MYI might survive the season.

To follow up with the floe I talked about yesterday (first pic), a second pic from today's Uni Hamburg AMSR2 images (courtesy of Wipneus who generates these images). It is very close to the river delta, still its area evolves very slowly day after day, in waters supposed to be 4ºC plus (my estimate was 6ºC)

Remember the work Epiphyte did last year following a large floe in the Laptev Sea. When these large floes, they go suddenly.

Poof, it's gone

Quote
The floe we are looking at here is a contiguous, high-albedo (snow-covered?) ~300km^2 chunk of ice at the edge of the pack. It remains so from 01-26 jul. On Jul 27, it becomes a little less bright and loses 10% of its area. Three days later - poof. It's gone.



Keep an eye on that ice floe, seaicesailor!
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oren

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Re: 2015 sea ice area and extent data
« Reply #723 on: July 22, 2015, 11:42:00 PM »
Just by looking at the regional charts without any physics/weather, I expect Beaufort will not melt out this year, as melting thus far has been too slow. On the other hand the ESS seems well on its way to melting out completely. The CAA and the CAB haven't reached their big inflection points yet.

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Re: 2015 sea ice area and extent data
« Reply #724 on: July 23, 2015, 12:08:41 AM »

Much of the ice will eventually melt, but I'd have said "all the ice" a week ago. I am starting to lean to the side that maybe some Beaufort MYI might survive the season.

To follow up with the floe I talked about yesterday (first pic), a second pic from today's Uni Hamburg AMSR2 images (courtesy of Wipneus who generates these images). It is very close to the river delta, still its area evolves very slowly day after day, in waters supposed to be 4ºC plus (my estimate was 6ºC)

Remember the work Epiphyte did last year following a large floe in the Laptev Sea. When these large floes, they go suddenly.

Poof, it's gone

Quote
The floe we are looking at here is a contiguous, high-albedo (snow-covered?) ~300km^2 chunk of ice at the edge of the pack. It remains so from 01-26 jul. On Jul 27, it becomes a little less bright and loses 10% of its area. Three days later - poof. It's gone.



Keep an eye on that ice floe, seaicesailor!

Nice! Thank you Neven and Epiphyte for that study. The more interesting to follow this.

Michael Hauber

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Re: 2015 sea ice area and extent data
« Reply #725 on: July 23, 2015, 01:14:13 AM »
IJIS extent stats show that in the last week2012's lead has been cut in half (600k to 310k), and that 2014 has now been overtaken.  Both Hudson and East Siberian (ESS) have been in freefall, and Hudson is nearly at bottom, so is about to stop.  Although there is not a lot of ice left in the ESS the melt can keep going into the central Arctic.  Although the high pressure system is moving towards the Siberian side of the Arctic, overall temperatures look to remain quite high.  I have noticed that although the charts show high pressure and heat the Arctic has been cloudy of late and hard to get a good view.  Fog or low level cloud from the extra sea water vapor perhaps?  There seems to be a lot of similarity between this year in 2007 with the very strong melt in the ESS, and it looks a good chance now that 2015 will join 2007 and 2012 as the only other previous years in which the tongue of ice towards and into ESS that usually remains at minimum is completely wiped out.

In common with 2012 we currently have a large area of sea ice that has been dispersed and is mixed with significant amounts of open water.  In both years the dispersal coincided with a low pressure system around 20 June, and it is my belief that this dispersal makes the ice more vulnerable to solar radiation being absorbed by the water in between the floes.   The dispersed ice in 2012 had a larger area, with a lot of the ice in the Laptev sector also being dispersed in 2012, but looking reasonably solid (in 2 dimensions) on MODIS in 2015.  There did not seem to be any significant dispersal in 2007. 

To challenge 2012 I think we will need to see strong melt in the Laptev region as well.  Winter patterns seemed to lead to very thin ice in this sector, but so far I'd say the conditions seem to have been average, and regional extent and area figures are trailing a little.  The forecast movement of the high towards the Siberian side might give a better MODIS view of this sector which has been mostly covered by clouds, and perhaps some extra sunshine will help the melt along.

I do get the impression of two Arctics - the Pacific side which is very dispersed and will continue to melt rapidly, and the central and Atlantic side which shows minimal dispersion, and may not melt as fast.  As a guess I think we may see continued fast melt through to mid August, but once much of the Pacific side ice is gone melt will slow down for an average finish to the melt season, and a final result somewhere near 2007.  I'll be looking at MODIS images in coming weeks for evidence of weakening that may support continued strong melt beyond the currently dispersed area.

edit:  oops, I thought I was posting in the current melt season thread....
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Neven

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Re: 2015 sea ice area and extent data
« Reply #726 on: July 23, 2015, 01:30:10 AM »
Post it there too, MH. :-)

Nice! Thank you Neven and Epiphyte for that study. The more interesting to follow this.

Maybe we should continue this Beaufort floe discussion over in the Melting season thread as well from now on. It's interesting, like you say. On the one hand it's MYI in the Beaufort, on the other hand, it's only July 23rd. I'll also try to keep an eye on it, if clouds permit.
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Re: 2015 sea ice area and extent data
« Reply #727 on: July 23, 2015, 04:11:06 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):

Sun       5.491770
Mon -93.7  5.398043
Tue -88.8  5.309246
Wed -115.6  5.193628
Thu -46.9  5.146720
Fri -73.5  5.073213
Sat -43.5  5.029723

The slower decline on Saturday is mainly caused by an uptick in the CAB (+34k5). Regions with significant declines are ESS (-22k8),  Kara (-16k5) and Baffin (-10k5).

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).

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Re: 2015 sea ice area and extent data
« Reply #728 on: July 23, 2015, 04:32:09 PM »
Very interesting. CT SIA decrease is showing signs of levelling off, even though weather conditions are remaining basically unchanged (perhaps slightly less heat), which is also causing CAPIE to level off.
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Re: 2015 sea ice area and extent data
« Reply #729 on: July 23, 2015, 04:34:58 PM »
NSIDC Daily Extent:

2012 was a leap year, now comparing same Julian days.

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361
2012,    07,  22,      7.184,  -113k....
2012,    07,  23,      7.118,   -66k
2012,    07,  24,      7.035,   -83k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg
« Last Edit: July 23, 2015, 04:59:04 PM by Vergent »

BornFromTheVoid

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Re: 2015 sea ice area and extent data
« Reply #730 on: July 23, 2015, 05:04:49 PM »
We're already approaching some of the older September minimum values. Just 339k off the 1980 minimum.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

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Re: 2015 sea ice area and extent data
« Reply #731 on: July 23, 2015, 07:22:05 PM »
We're already approaching some of the older September minimum values. Just 339k off the 1980 minimum.

Where CT SIA is concerned--and using Wipneus' numbers--2015 has already dropped below the annual minimums recorded in 1979, 1980, 1982, 1983, 1986, 1987, 1988, and 1996.

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Re: 2015 sea ice area and extent data
« Reply #732 on: July 23, 2015, 10:06:19 PM »
In regards to ADS-NIPR (formerly IJIS) Sea Ice Extent, the last 7 days have seen a loss of slightly over 908K Km2.  It will be interesting to watch if 2015 will continue have above average losses through the middle of August.  Personally, I can not see any path for 2015 to eclipse 2012.  As for 2011 & 2007, they are vulnerable but not yet seriously threatened.  Will update and post my graphs and projections sometime over the weekend.
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Re: 2015 sea ice area and extent data
« Reply #733 on: July 24, 2015, 01:41:14 PM »
ADS-NIPR Extent:
7,201,855 km2 (23 July)
Down 6,740,205 km2 (48.34%) from 2015 maximum of 13,942,060 km2 on 15 February.
4,024,400 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 100,037 km2 (-1.37%)from previous day.
Down 853,064 km2  (-10.59%) over past seven days (daily average: -121,866 km2).
Down 2,280,461 km2  (-24.05%) for July (daily average: -99,150 km2).
759,008 km2 below 2000s average for this date.
94,470 km2 above 2010s average for this date.
130,079 km2 below 2014 value for this date.
262,717 km2 above 2012 value for this date.
8th lowest July to-date average.
5th lowest value for the date.
64 days this year (31.37% year-to-date) have recorded the lowest daily extent.
32 days (15.69%) have recorded the second lowest.
32 days (15.69%) have recorded the third lowest.
128 days (62.75%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
5,029,723 km2 (24 July [Day 0.559])
Down 8,244,832 km2 (62.11%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,795,714 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 43,386 km2 (-0.86%) from previous day.
Down 585,919 km2 (-10.43%) over past seven days (daily average: -83,703 km2).
Down 2,425,098 km2 (-32.53%) for July (daily average: -101,046 km2).
601,598 km2 below 2000s average for this date.
146,046 km2 above 2010s average for this date.
197,054 km2 below 2014 value for this date.
580,316 km2 above 2012 value for this date.
5th lowest July to-date average.
5th lowest value for the date.
7 days this year (3.41% year-to-date) have recorded the lowest daily area.
19 days (9.27%) have recorded the second lowest.
29 days (14.15%) have recorded the third lowest.
55 days in total (26.83%) have been among the lowest three on record.

« Last Edit: July 24, 2015, 01:52:50 PM by Jim Pettit »

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Re: 2015 sea ice area and extent data
« Reply #734 on: July 24, 2015, 03:56:28 PM »
NSIDC Daily Extent:

2012 was a leap year, now comparing same Julian days.

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361k
2012,    07,  22,      7.184,  -113k....2015,    07,   23,      7.548,   -110k.....+364k
2012,    07,  23,      7.118,   -66k
2012,    07,  24,      7.035,   -83k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg
« Last Edit: July 24, 2015, 04:23:50 PM by Vergent »

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Re: 2015 sea ice area and extent data
« Reply #735 on: July 24, 2015, 04:13:49 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):

Fri       5.072222
Sat -43.6  5.028612
Sun -87.0  4.941621

Sunday's decline (increased by "lake ice" -10k4) is supported by the CAB(-20k6), ESS (-20k3) and Kara (-14k9).

Beaufort drops in extent (-15k8 NSIDC calculation) yet the area increases a little (+7k5 CT calculation).

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).

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Re: 2015 sea ice area and extent data
« Reply #736 on: July 25, 2015, 03:57:18 PM »
NSIDC Daily Extent:

2012 was a leap year, now comparing same Julian days.

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361k
2012,    07,  22,      7.184,  -113k....2015,     07,   23,     7.548,   -110k.....+364k
2012,    07,  23,      7.118,   -66k.....2015,     07,  24,      7.434,   -114k.....+316k
2012,    07,  24,      7.035,   -83k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg

Bob Wallace

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Re: 2015 sea ice area and extent data
« Reply #737 on: July 25, 2015, 04:50:14 PM »
In regards to ADS-NIPR (formerly IJIS) Sea Ice Extent, the last 7 days have seen a loss of slightly over 908K Km2.  It will be interesting to watch if 2015 will continue have above average losses through the middle of August.  Personally, I can not see any path for 2015 to eclipse 2012.  As for 2011 & 2007, they are vulnerable but not yet seriously threatened.  Will update and post my graphs and projections sometime over the weekend.

If you look at Wip's graph for the central basin 2015 extent is lower than 2012 at this time.  This doesn't say that 2015 will finish lower, but it does leave the possibility that weather similar to 2012 could take the melt to a new low.


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Re: 2015 sea ice area and extent data
« Reply #738 on: July 25, 2015, 04:59:52 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):

Fri         5.072222
Sat  -43.6  5.028612
Sun  -86.9  4.941706
Mon -183.3  4.758386

The large day-to-day changes seem to back. The big decline on Monday (which includes a -17k from "lake ice") is mainly brought by the CAB (-60k), CAA (-29k), Baffin (-25k). Smaller contributions (~-12k) by Laptev, ESS and Greenland Sea.

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).

Neven

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Re: 2015 sea ice area and extent data
« Reply #739 on: July 25, 2015, 05:09:46 PM »
So much for signs of levelling off. With that 183K drop 2015 dips below 2013, in 4th position now. And depending on JAXA SIE, CAPIE will drop some more too.
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Re: 2015 sea ice area and extent data
« Reply #740 on: July 25, 2015, 05:41:12 PM »
Days like this makes such a difference. 2014 is already firmly distanced and 2013 starts going uphill from here. The chance of 2015 finishing above those years has now reached statistically insignificant, as far as I can see, that goes for 2009 as well.

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Re: 2015 sea ice area and extent data
« Reply #741 on: July 25, 2015, 05:44:41 PM »
The chance of 2015 finishing above those years has now reached statistically insignificant, as far as I can see, that goes for 2009 as well.

Be careful, RC! Anything is possible in the Arctic, but that goes both ways, of course.
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Re: 2015 sea ice area and extent data
« Reply #742 on: July 25, 2015, 06:20:15 PM »
Yes, just as regions with little relevance have been giving the last they had very fast (Baffin and Hudson), regions with a lot of potential to turn the balance in either direction are being slow (Chukchi and Beaufort).

ESS is a rocket, just opposite to previous years.
Laptev finally going down fast.

Chukchi front (which is entering the CAB, or so), is especially slow compared to 10 days ago.

Edit: talking about extent.

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Re: 2015 sea ice area and extent data
« Reply #743 on: July 25, 2015, 07:08:22 PM »
So much for signs of levelling off. With that 183K drop 2015 dips below 2013, in 4th position now. And depending on JAXA SIE, CAPIE will drop some more too.

Poof.

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #744 on: July 25, 2015, 09:38:35 PM »
So much for signs of levelling off. With that 183K drop 2015 dips below 2013, in 4th position now. And depending on JAXA SIE, CAPIE will drop some more too.

Yes. And with that drop, 2015 has dropped below the area minimums recorded in 1979-1983, 1985-1989, 1992, 1994, 1996, and 1997.

That 183k drop is the third largest post-25 July single-day decrease recorded in the previous ten years. (How's that for obscure?)

Tor Bejnar

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Re: 2015 sea ice area and extent data
« Reply #745 on: July 25, 2015, 10:52:09 PM »
Quote
(How's that for obscure?)
Sounds like you are attempting to get us to fact check your statement. :D
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Re: 2015 sea ice area and extent data
« Reply #746 on: July 26, 2015, 02:12:51 PM »
ADS-NIPR Extent:
7,001,792 km2 (25 July)
Down 6,940,268 km2 (49.78%) from 2015 maximum of 13,942,060 km2 on 15 February.
3,824,337 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 115,285 km2 (-1.62%) from previous day.
Down 765,209 km2  (-9.85%) over past seven days (daily average: -109,316 km2).
Down 2,480,524 km2  (-26.16%) for July (daily average: -99,221 km2).
796,865 km2 below 2000s average for this date.
55,300 km2 above 2010s average for this date.
252,433 km2 below 2014 value for this date.
384,485 km2 above 2012 value for this date.
7th lowest July to-date average.
5th lowest value for the date.
64 days this year (31.07% year-to-date) have recorded the lowest daily extent.
32 days (15.53%) have recorded the second lowest.
32 days (15.53%) have recorded the third lowest.
128 days (62.14%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
4,758,386 km2 (26 July [Day 0.5643])
Down 8,516,169 km2 (64.15%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,524,377 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 183,235 km2 (-3.71%) from previous day.
Down 640,224 km2 (-11.86%) over past seven days (daily average: -91,461 km2).
Down 2,696,435 km2 (-36.17%) for July (daily average: -103,709 km2).
737,843 km2 below 2000s average for this date.
26,718 km2 above 2010s average for this date.
345,099 km2 below 2014 value for this date.
417,014 km2 above 2012 value for this date.
5th lowest July to-date average.
4th lowest value for the date.
7 days this year (3.38% year-to-date) have recorded the lowest daily area.
19 days (9.18%) have recorded the second lowest.
29 days (14.01%) have recorded the third lowest.
55 days in total (26.57%) have been among the lowest three on record.

Neven

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Re: 2015 sea ice area and extent data
« Reply #747 on: July 26, 2015, 02:24:09 PM »
And as expected, CAPIE dips, despite a century break from IJIS (I'll start calling them differently next year):
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Re: 2015 sea ice area and extent data
« Reply #748 on: July 26, 2015, 02:41:05 PM »
The last 10 days has seen a loss of slightly more than 1.2M Km2 of SIE according to ADR-NIPR.  I think it's safe to say that the rebound is finally over.  With the current forecasts and the general state of the ice, 2015 will most probably finish the season between 3rd and 5th lowest on record.  With well above average losses in August, there's even a possibility of eclipsing 2007.  The reason 2012 is so difficult to beat is that it lost almost 2.6M Km2 in August.

Below are my updated charts and a table of projected loss scenarios, based on the average losses of years 2003-2014.



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Re: 2015 sea ice area and extent data
« Reply #749 on: July 26, 2015, 03:54:01 PM »
NSIDC Daily Extent:

2012 was a leap year, now comparing same Julian days.

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361k
2012,    07,  22,      7.184,  -113k....2015,     07,   23,     7.548,   -110k.....+364k
2012,    07,  23,      7.118,   -66k.....2015,     07,  24,      7.434,   -114k.....+316k
2012,    07,  24,      7.035,   -83k.....2015,     07,  25,      7.320,   -114k.....+285k
2012,    07,  25,      6.931,  -104k
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

Verg