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DavidR

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Re: 2015 sea ice area and extent data
« Reply #850 on: August 14, 2015, 03:54:23 PM »
...
I have looked at a different metric which far from precise in any way may still give some hints. I calculated the average day of minimum (day  255  = Sep 12) and then calculated the needed daily loss just using an unrealistic straight line. Obviously the melt currently must exceed that daily average (see last two columns):
:
Rank Year Month Day DoY Area Total loss Days to go Daily loss
1 2012 9 13 257 2.2340095 -1.8446062 38 -48542
2 2011 9 11 254 2.9047396 -1.1738761 38 -30892
3 2007 9 8 251 2.9194391 -1.1591766 38 -30505
4 2008 9 8 252 3.0035558 -1.0750599 38 -28291
5 2010 9 9 252 3.0721295 -1.0064862 38 -26487
6 2009 9 10 253 3.4245975 -0.6540182 38 -17211
7 2014 9 11 254 3.4831684 -0.5954473 38 -15670
8 2013 9 11 254 3.5543971 -0.5242186 38 -13795
9 2006 9 24 267 4.0169191 -0.0616966 38 -1624
10 2002 9 7 250 4.0347104 -0.0439053 38 -1155
11 2015 8 5 217 4.0786157 0 38 0

Update on the table shown above:
:
Rank Year Month Day DoY Area Needed loss Days to go Daily loss
1 2012 9 13 257 2.2340095 -1.3527329 30 -45091.1
2 2011 9 11 254 2.9047396 -0.6820028 30 -22733.4
3 2007 9 8 251 2.9194391 -0.6673033 30 -22243.4
4 2008 9 8 252 3.0035558 -0.5831866 30 -19439.6
5 2010 9 9 252 3.0721295 -0.5146129 30 -17153.8
6 2009 9 10 253 3.4245975 -0.1621449 30 -5404.8
7 2014 9 11 254 3.4831684 -0.1035740 30 -3452.5
8 2013 9 11 254 3.5543971 -0.0323453 30 -1078.2
9 2015 8 13 225 3.5867424 0 30 0

Some notes: there is a cluster at around 3.4-3.5 (2009, 2014 and 2013), which will presumably soon be passed (need only 162k which is perhaps a week or less?). The next cluster is at 2.9-3.1 (2011, 2007, 2008, 2010) which needs about 680k to pass. There are still 30 days of melt till the average day of minimum, and if the minimum will be late then perhaps up to 40 days. The last "cluster" is of course the 2012 outlier at 2.23.
plg ,
these figures are out by  a couple of days as the current SIA figures we have are for 11 Aug so there are 32 days to  the 12th Sept. 
The AVERAGE decline between now and then since 2007  has been 750K km^2 meaning that the only  year  that  is safe from an average melt is 2012 , and a stronger than average melt will take the figures down near 2012.

plg

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Re: 2015 sea ice area and extent data
« Reply #851 on: August 14, 2015, 04:02:02 PM »
...
...

Some notes: there is a cluster at around 3.4-3.5 (2009, 2014 and 2013), which will presumably soon be passed (need only 162k which is perhaps a week or less?). The next cluster is at 2.9-3.1 (2011, 2007, 2008, 2010) which needs about 680k to pass. There are still 30 days of melt till the average day of minimum, and if the minimum will be late then perhaps up to 40 days. The last "cluster" is of course the 2012 outlier at 2.23.
plg ,
these figures are out by  a couple of days as the current SIA figures we have are for 11 Aug so there are 32 days to  the 12th Sept. 
The AVERAGE decline between now and then since 2007  has been 750K km^2 meaning that the only  year  that  is safe from an average melt is 2012 , and a stronger than average melt will take the figures down near 2012.

True, my mistake. I was using the data directly from CT, not Wipneus latest, and did not adjust the dates.

Re the average decline in recent years, that would make a second place very likely(?).
If you are not paranoid you just do not have enough information yet.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #852 on: August 14, 2015, 06:10:43 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):

day   chg  estimate  CT-value
Fri        3.587187  3.586742
Sat  -5.7  3.581451  -
Sun -11.3  3.570197  -

Another slow day, a decline just because the "lake ice" dropped -19k. The CAB saw an increase of +17k8.

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).

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #853 on: August 15, 2015, 04:10:54 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):

day   chg  estimate  CT-value
Sat        3.581451  3.580919
Sun -11.5  3.569984  -
Mon +40.8  3.610802  -

Relative large uptick is caused by an increase of area in the CAB (+61k6). The decline in the Beaufort (-13k4) eased it a bit.

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).

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #854 on: August 16, 2015, 02:26:41 PM »
The ADR-NIPR Extent losses have really tapered off in the last week, which  is somewhat normal for this time of the year.  The average daily loss for the first 15 days of August, 2015, was 69,404 KM2, which  is only slightly below the 2003-2014 average of 70,118 KM2/day..

In looking ahead to the last 16 days of August the average daily losses are only 47,007 KM2.  The maximum average daily loss of  64,991 KM2 was in 2012.

It will take well above average losses for the  remainder of the melt season for 2015 to go below 2011 and record losses to end up 2nd below 2007.  It looks more likely that 2015 will end up 4th.  See latest chart and my table of projections below:




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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #855 on: August 16, 2015, 02:53:57 PM »
The ADR-NIPR Extent losses have really tapered off in the last week, which  is somewhat normal for this time of the year.  The average daily loss for the first 15 days of August, 2015, was 69,404 KM2, which  is only slightly below the 2003-2014 average of 70,118 KM2/day..

In looking ahead to the last 16 days of August the average daily losses are only 47,007 KM2.  The maximum average daily loss of  64,991 KM2 was in 2012.

It will take well above average losses for the  remainder of the melt season for 2015 to go below 2011 and record losses to end up 2nd below 2007.  It looks more likely that 2015 will end up 4th.

It's much the same story with CT SIA. After a two-week period that saw area drop by 945k, it's now increased by 24k over the past three days. Of course, last year saw a rise of 36k over the same three-day period, which contrasts with the 46k lost in 2013, the 146k lost in 2012, and the 314k lost in 2007. All of that to say: second and even third place are becoming more unlikely by the day, so 4th place may indeed by the result.

budmantis

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Re: 2015 sea ice area and extent data
« Reply #856 on: August 16, 2015, 03:25:50 PM »
If the recent slowdown continues, 2008 could very well catch up and surpass this year, resulting in a fifth place finish for 2015.

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Re: 2015 sea ice area and extent data
« Reply #857 on: August 16, 2015, 03:34:58 PM »
FOX (TASS) News....."The Trump Channel.....where truth and journalism are dead."

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Re: 2015 sea ice area and extent data
« Reply #858 on: August 16, 2015, 04:10:13 PM »
If the recent slowdown continues, 2008 could very well catch up and surpass this year, resulting in a fifth place finish for 2015.

Here are the CT area losses from this day through the annual minimum for each of the previous ten seasons, with a third column showing where 2015 would end up were it to follow each of those years from here on out, and a 4th column showing final rank:

YEAR   LOSS TO END   IF REPEATED   RANK
2014   1.0883119   2.4816721   2nd
2013   0.5946255   2.9753585   4th
2012   0.7335148   2.8364692   2nd
2011   0.5325577   3.0374263   5th
2010   0.9297531   2.6402309   2nd
2009   0.6761916   2.8937924   2nd
2008   0.6316180   2.9383660   4th
2007   0.3827111   3.1872729   6th
2006   0.5312524   3.0387316   5th
2005   0.2562065   3.3137775   6th

Note that the space between 2nd place and 6th place is very thin: 2.903M would put 2015 in 2nd, while just 3.073--about 170k higher--would leave 2015 in 6th.

It's like watching Arctic Sea Ice Roulette: round and round it goes, and where it stops, nobody knows...
« Last Edit: August 16, 2015, 04:15:55 PM by Jim Pettit »

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #859 on: August 16, 2015, 04:39:29 PM »
If the recent slowdown continues, 2008 could very well catch up and surpass this year, resulting in a fifth place finish for 2015.

Here are the CT area losses from this day through the annual minimum for each of the previous ten seasons, with a third column showing where 2015 would end up were it to follow each of those years from here on out, and a 4th column showing final rank:

YEAR   LOSS TO END   IF REPEATED   RANK
2014   1.0883119   2.4816721   2nd
2013   0.5946255   2.9753585   4th
2012   0.7335148   2.8364692   2nd
2011   0.5325577   3.0374263   5th
2010   0.9297531   2.6402309   2nd
2009   0.6761916   2.8937924   2nd
2008   0.6316180   2.9383660   4th
2007   0.3827111   3.1872729   6th
2006   0.5312524   3.0387316   5th
2005   0.2562065   3.3137775   6th

Note that the space between 2nd place and 6th place is very thin: 2.903M would put 2015 in 2nd, while just 3.073--about 170k higher--would leave 2015 in 6th.

It's like watching Arctic Sea Ice Roulette: round and round it goes, and where it stops, nobody knows...


Jim,

It is amazing how that small difference could make such a big difference in how the pundits will view, and comment on, this year's melt season.  If 2015 ends up in 2nd place, the WUWT crowd will have trouble claiming that the Arctic ice is recovering.  On the other if 2015 ends up in 6th place, we will have more trouble trying to convince people that the Arctic ice is rapidly declining.
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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #860 on: August 16, 2015, 05:30:20 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):

day   chg  estimate  CT-value
Sat        3.581451  3.580919
Sun -11.5  3.569984  -
Mon +40.9  3.610883  -
Tue -16.8  3.594115  -

Back to the small declines, despite continuing increases in the CAB (+18k1). Beaufort dropped -11k9.

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 #861 on: August 16, 2015, 05:52:12 PM »
Update for the week to August 15th

The current 5 day mean is on 5,842,220km2 while the 1 day extent is at 5,706,000km2.
The daily anomaly (compared to 81-10) is at -1,461,340km2, an increase from -1,359,140km2 last week. The anomaly compared to the 07, 11 and 12 average is at +525,733km2, an increase from +453,267km2 last week. We're currently 4th lowest on record, the same as last week.



The average daily change over the last 7 days was -77.3k/day, compared to the long term average of -62.7k/day, and the 07, 11 and 12 average of -87.7k/day.
The average long term change over the next week is -51.3k/day, with the 07, 11, and 12 average being -68.3k/day.



The loss so far this August is the 7th largest on record. To achieve the largest monthly drop, a daily loss of at least 98.2k/day is required, while the smallest drop requires a loss of no more than 2.3k/day and an average drop requires a loss of 35.6k/day.


budmantis

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Re: 2015 sea ice area and extent data
« Reply #862 on: August 16, 2015, 06:16:12 PM »
Maybe you should take a look at volume....:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150815.png



Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.

budmantis

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Re: 2015 sea ice area and extent data
« Reply #863 on: August 16, 2015, 06:23:41 PM »
If the recent slowdown continues, 2008 could very well catch up and surpass this year, resulting in a fifth place finish for 2015.

Here are the CT area losses from this day through the annual minimum for each of the previous ten seasons, with a third column showing where 2015 would end up were it to follow each of those years from here on out, and a 4th column showing final rank:

YEAR   LOSS TO END   IF REPEATED   RANK
2014   1.0883119   2.4816721   2nd
2013   0.5946255   2.9753585   4th
2012   0.7335148   2.8364692   2nd
2011   0.5325577   3.0374263   5th
2010   0.9297531   2.6402309   2nd
2009   0.6761916   2.8937924   2nd
2008   0.6316180   2.9383660   4th
2007   0.3827111   3.1872729   6th
2006   0.5312524   3.0387316   5th
2005   0.2562065   3.3137775   6th

Note that the space between 2nd place and 6th place is very thin: 2.903M would put 2015 in 2nd, while just 3.073--about 170k higher--would leave 2015 in 6th.

It's like watching Arctic Sea Ice Roulette: round and round it goes, and where it stops, nobody knows...


Jim: It was about this time last year that I made my first post on the forum. It looked at that time that 2014 would end up finishing higher than 2005. I noticed that if this year has an equal amount of melt as 2014 going forward, it would finish in second place! I guess the last thirty days of the melt season can make a big difference after all. Bud

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #864 on: August 16, 2015, 07:45:32 PM »
It is amazing how that small difference could make such a big difference in how the pundits will view, and comment on, this year's melt season.  If 2015 ends up in 2nd place, the WUWT crowd will have trouble claiming that the Arctic ice is recovering.  On the other if 2015 ends up in 6th place, we will have more trouble trying to convince people that the Arctic ice is rapidly declining.

Good points, OLN. But then again, if if all the ice melted out this year, silly people would still claim October's refreeze as proof of a recovery. ;)

It was about this time last year that I made my first post on the forum. It looked at that time that 2014 would end up finishing higher than 2005. I noticed that if this year has an equal amount of melt as 2014 going forward, it would finish in second place! I guess the last thirty days of the melt season can make a big difference after all. Bud

Yes, indeed. About the only thing I'd bet on at this point is that 2015 SIA will not make first place, nor will it wind up further back than sixth place. Aside from those near-certainties, it's all still pretty much up in the air at this point.

seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #865 on: August 17, 2015, 01:47:13 AM »
SIE fell by 500K in 6 days. Another week and the daily extent will be below the '13 and '14 Sep averages.

Bill Fothergill

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Re: 2015 sea ice area and extent data
« Reply #866 on: August 17, 2015, 02:46:53 PM »
The CT Arctic SIA for 2015.6219 has just been posted as 3.612 million sq kms.

However, the date stamp has jumped from 2015.6165 thus stepping over the expected value of 2015.6191 for Day 226. There may therefore be a correction published, as the numbers posted earlier by Wipneus suggest that we should see an intermediate value of around 3.57 prior to the uptick to approx 3.612

Lou

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Re: 2015 sea ice area and extent data
« Reply #867 on: August 17, 2015, 03:40:32 PM »
Maybe you should take a look at volume....:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150815.png



Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.


Taking a step or three back from the daily Arctic horse race(s), I think this volume vs. area/extent relationship will continue to be the norm.  The ice will continue to thin but not plummet in area or extent until we're very close to a Blue Arctic Event.  When we make that final plunge in the weeks before the first BAE humanity has ever seen it could be one of the largest and most dramatic examples of a tipping points imaginable.

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Re: 2015 sea ice area and extent data
« Reply #868 on: August 17, 2015, 04:12:51 PM »
The CT Arctic SIA for 2015.6219 has just been posted as 3.612 million sq kms.

However, the date stamp has jumped from 2015.6165 thus stepping over the expected value of 2015.6191 for Day 226. There may therefore be a correction published, as the numbers posted earlier by Wipneus suggest that we should see an intermediate value of around 3.57 prior to the uptick to approx 3.612

Bill, welcome to the forum.

This usually (always until now) gets corrected. Note that the 3.612 is probably correct for the Monday data release, but the average value (last column) is the value for Sunday!

crandles

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Re: 2015 sea ice area and extent data
« Reply #869 on: August 17, 2015, 04:24:59 PM »
Maybe you should take a look at volume....:


Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.


Taking a step or three back from the daily Arctic horse race(s), I think this volume vs. area/extent relationship will continue to be the norm. 


What  'this relationship' is that?

eg


or



both from http://dosbat.blogspot.co.uk/2013/01/a-correction-from-brink.html

or something else?

Well obviously it cannot be a continuation of the first graph as you cannot have positive area and negative volume. However you comment seem to suggest we continue to get substantial area until suddenly one year we don't.

I think a constant ratio of area to thickness resulting in the second graph is much more plausible.

To add to this, your sudden disappearance seems possible if the sea ice is of more or less constant thickness and it gradually thins over the years then suddenly it all disappears. However the reality is that the ice is more wedge shaped getting thinner towards the edges so you lose area as well as thickness over time. It is more complicated to see this if you imagine lots of leads and broken ice but similar distribution of sizes of pieces just moving towards smaller sizes over time also fits with the second graph rather than the first graph.

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Re: 2015 sea ice area and extent data
« Reply #870 on: August 17, 2015, 04:31:45 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):

day   chg  estimate  CT-value
Mon        3.610883  3.612094
Tue -16.7  3.594170  -
Wed -81.9  3.512253  -

Wednesday's decline came from the CAB (-53k3), CAA (-17k5) and the Greenland Sea (-10k9)

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 #871 on: August 17, 2015, 05:02:55 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):

day   chg  estimate  CT-value
Mon        3.610883  3.612094
Tue -16.7  3.594170  -
Wed -81.9  3.512253  -


Nice. Thanks. So that will put current area more than a million square kilometers below last year's value for the same day. And with about a month still left for ice to disappear, area has already dropped below 2013's annual minimum (and the minimums recorded in all other years prior to 2007).

Huh. I gotta tell you, that's some recovery, ain't it, Anthony? ;)

For the record, 2015's August average is already lower than those recorded for the full month in 2014, 2013, 2010, 2009, and every year prior to 2007. Now let's see what the next two weeks can bring...
« Last Edit: August 17, 2015, 05:08:29 PM by Jim Pettit »

Buddy

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Re: 2015 sea ice area and extent data
« Reply #872 on: August 17, 2015, 05:24:45 PM »
The "concentration map" provided by Wipneus above....shows a LOT of area that has lost MORE than 7% concentration.

Next couple weeks could prove interesting......

Between THAT.....and the Antarctic sea ice level BELOW the average level from 1979 - 2010....this is not setting up to be a good year for those who don't believe in science (Snthony Watts, Joe Bastardi, FOX Noise, Sean Hannity, almost all the Republican candidates for US President, etc.)

They are REALLY going to hate it when the most important issue in the 2016 presidential election is climate change...:)

What happens NEXT YEAR when the ice sheet takes a dive to new record lows TWO MONTHS BEFORE THE ELECTION?

Next 13 months will be interesting.....
FOX (TASS) News....."The Trump Channel.....where truth and journalism are dead."

oren

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Re: 2015 sea ice area and extent data
« Reply #873 on: August 17, 2015, 05:54:01 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):

day   chg  estimate  CT-value
Mon        3.610883  3.612094
Tue -16.7  3.594170  -
Wed -81.9  3.512253  -

Wednesday's decline came from the CAB (-53k3), CAA (-17k5) and the Greenland Sea (-10k9)

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).

Parts of the Beaufort and Greenland Sea have taken a big hit.

Nick_Naylor

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Re: 2015 sea ice area and extent data
« Reply #874 on: August 17, 2015, 06:04:00 PM »
They are REALLY going to hate it when the most important issue in the 2016 presidential election is climate change...:)

What happens NEXT YEAR when the ice sheet takes a dive to new record lows TWO MONTHS BEFORE THE ELECTION?

Don't get your hopes up - this is heaven to these guys. They're like F. Lee Bailey or Johnnie Cochran. The more obviously guilty their client and the more high-profile the debate, the more they love it.

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Re: 2015 sea ice area and extent data
« Reply #875 on: August 17, 2015, 10:01:27 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):

day   chg  estimate  CT-value
Mon        3.610883  3.612094
Tue -16.7  3.594170  -
Wed -81.9  3.512253  -


I will be interested to see how those losses in area will impact the extent  measurements for those days.

Nice. Thanks. So that will put current area more than a million square kilometers below last year's value for the same day. And with about a month still left for ice to disappear, area has already dropped below 2013's annual minimum (and the minimums recorded in all other years prior to 2007).

Huh. I gotta tell you, that's some recovery, ain't it, Anthony? ;)

For the record, 2015's August average is already lower than those recorded for the full month in 2014, 2013, 2010, 2009, and every year prior to 2007. Now let's see what the next two weeks can bring...
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Re: 2015 sea ice area and extent data
« Reply #876 on: August 17, 2015, 10:45:24 PM »
The more obviously guilty their client and the more high-profile the debate, the more they love it.

Yes....absolutely true.  But I like playing poker against someone when I have a royal flush....and I know they don't even have a pair of deuces.

They are paid to lie...and they lie as long or longer than the tobacco industry.  I almost (but not quite:) feel sorry for someone that lies for a living.  But then.....look how easy it is for FOX News to fill their roster of "fake journalists."
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Re: 2015 sea ice area and extent data
« Reply #877 on: August 18, 2015, 12:26:24 AM »
Dont think sea ice votes.... Nor do I think politics belong in thread about area and extent of sea ice.

Michael J

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Re: 2015 sea ice area and extent data
« Reply #878 on: August 18, 2015, 01:05:00 AM »
The "concentration map" provided by Wipneus above....shows a LOT of area that has lost MORE than 7% concentration.

Next couple weeks could prove interesting......

Between THAT.....and the Antarctic sea ice level BELOW the average level from 1979 - 2010....this is not setting up to be a good year for those who don't believe in science (Snthony Watts, Joe Bastardi, FOX Noise, Sean Hannity, almost all the Republican candidates for US President, etc.)

They are REALLY going to hate it when the most important issue in the 2016 presidential election is climate change...:)

What happens NEXT YEAR when the ice sheet takes a dive to new record lows TWO MONTHS BEFORE THE ELECTION?

Next 13 months will be interesting.....

Do we have an idea of how much of the pink areas is actual ice loss and how much is it the ice just rearranging itself?

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Re: 2015 sea ice area and extent data
« Reply #879 on: August 18, 2015, 02:47:15 AM »
They are REALLY going to hate it when the most important issue in the 2016 presidential election is climate change...:)

What happens NEXT YEAR when the ice sheet takes a dive to new record lows TWO MONTHS BEFORE THE ELECTION?

Don't get your hopes up - this is heaven to these guys. They're like F. Lee Bailey or Johnnie Cochran. The more obviously guilty their client and the more high-profile the debate, the more they love it.
The three big environment  issues for 2016 will be:
1: Farewell to 400: The last time CO2 levels fall below 400ppm in our lifetimes.

2: The temperature record trifecta: 2014 - 2016 all setting global temperature records. Its worth remembering that the El Nino that caused 1998 to set a global temperature record actually  finished in Apr 1998. With this one predicted to finish in Apr 2016 there is a strong  possibility of a third successive global record next year.

3: Record Arctic Sea Ice low: Given the El Nino and this years conditions I believe this is now highly  probable.

slow wing

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Re: 2015 sea ice area and extent data
« Reply #880 on: August 18, 2015, 06:51:46 AM »
What do I know?

I thought the extent would have been dropping fast over the past week or so. However, it looks like there simply isn't enough heat in the system.

   Looking at Worldview, even the gap inside the Beaufort Arm appears to retain lots of broken up sludge. So the temperature at the water's surface will be constrained to be the melting temperature of the ice - i.e. somewhere between 0 and around -2 degrees C, depending how much salt is in the ice.

 To address the areas that actually are melting out, the Beaufort Arm is slowly dissolving away. And out in the fringes, much of the ice in the Greenland Sea is being eaten away.

 But the rest of the ice in the Central Arctic seems to be mostly blowing around with not too much area loss. Certainly there are patchy gaps, here and there, now showing over much of the ice pack and extending pretty much all the way to the Pole.

But there are no big areas of melt in the main ice pack - no regions showing green on the map for under 50% concentration. Unless there is a big storm, it looks like the bottom melt will probably be 'too little, too late' for any dramatic changes.

  Look at the example of the ice edge on the Atlantic side. It has hardly budged over the past 10 days.

  I'm thinking now that the extent is going to remain relatively large. The pack may compact. Equally though, it may instead expand out into open waters in some parts of its perimeter.

 And then it will refreeze.


Click on gif to animate the U. Bremen concentration maps for the past 10 days:


jdallen

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Re: 2015 sea ice area and extent data
« Reply #881 on: August 18, 2015, 06:57:44 AM »
What do I know?

I thought the extent would have been dropping fast over the past week or so. However, it looks like there simply isn't enough heat in the system.

   Looking at Worldview, even the gap inside the Beaufort Arm appears to retain lots of broken up sludge. So the temperature at the water's surface will be constrained to be the melting temperature of the ice - i.e. somewhere between 0 and around -2 degrees C, depending how much salt is in the ice.

 To address the areas that actually are melting out, the Beaufort Arm is slowly dissolving away. And out in the fringes, much of the ice in the Greenland Sea is being eaten away.

 But the rest of the ice in the Central Arctic seems to be mostly blowing around with not too much area loss. Certainly there are patchy gaps, here and there, now showing over much of the ice pack and extending pretty much all the way to the Pole.

But there are no big areas of melt in the main ice pack - no regions showing green on the map for under 50% concentration. Unless there is a big storm, it looks like the bottom melt will probably be 'too little, too late' for any dramatic changes.

  Look at the example of the ice edge on the Atlantic side. It has hardly budged over the past 10 days.

  I'm thinking now that the extent is going to remain relatively large. The pack may compact. Equally though, it may instead expand out into open waters in some parts of its perimeter.

 And then it will refreeze.


Click on gif to animate the U. Bremen concentration maps for the past 10 days:
Au Contraire! My friend...

Judging from Jim Petitt's posts, CT Area suggests we have a very good chance of blowing by both 2007 and 2011 end of season area numbers.  Only 590K or so required, and easily 2 weeks to go in the season.  I'm thinking there is plenty of heat left to do that.

Now here's the thing; we could be in a very odd position.  We *could* see the season end with 2015 4th or even 5th in extent, but 2nd in SIA.

(o.O)

A very strange and very disturbing season for sure...
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seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #882 on: August 18, 2015, 08:35:41 AM »
Amen JD. I was gonna reply myself, maybe later.
And then it will refreeze. That, is true. The rest, ahem.

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Re: 2015 sea ice area and extent data
« Reply #883 on: August 18, 2015, 08:49:21 AM »
Oops! I was meaning to post that on the 'melting season' thread. I just did, but I will also leave it here as you have already replied. Sorry.


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Re: 2015 sea ice area and extent data
« Reply #884 on: August 18, 2015, 07:19:06 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):

day   chg  estimate  CT-value
Tue        3.594170  3.594853
Wed -81.9  3.512301  -
Thu -57.7  3.454562  -

Thursday's decline can be near fully attributed to the CAB which dropped -57k.

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 #885 on: August 18, 2015, 08:25:52 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):

day   chg  estimate  CT-value
Tue        3.594170  3.594853
Wed -81.9  3.512301  -
Thu -57.7  3.454562  -

Thursday's decline can be near fully attributed to the CAB which dropped -57k.

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).

Thanks, Wipneus. That moves 2015 SIA ahead of 2013, and into 7th place. If the remainder of the melt season follows the trajectories of 2014, 2012, 2010, or 2008, 2015 will end up in 2nd place, while copying the ending behavior of 2013, 2011, or 2009 would leave 2015 in 5th.

Here's an updated list of how much further CT area needs to fall to move into each of the six remaining ranks:

6th   29966
5th   382434
4th   451007
3rd   535124
2nd   549823
1st   1220554

As said before, with nearly a month left in the loss season, 6th place is a shoe-in, while first is all but impossible (knock on wood ice). That leaves 2nd through 5th places up for grabs--and note that the average to-minimum loss for the post-2007 years has been 614k km2.

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Re: 2015 sea ice area and extent data
« Reply #886 on: August 19, 2015, 12:39:07 AM »
As said before, with nearly a month left in the loss season, 6th place is a shoe-in, while first is all but impossible (knock on wood ice). That leaves 2nd through 5th places up for grabs--and note that the average to-minimum loss for the post-2007 years has been 614k km2.
Jim,
given that 2007 is one of the years in play wouldn't it  be better to include 2007 in your average and analysis.  Including 2007 lowers the average loss to 569k km^2 and a drop in line with that of 2007 would leave us in 6th place.

Having said that I am still happy with my  poll prediction of 2.5 - 2.75.

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #887 on: August 19, 2015, 04:40:01 AM »
Jim,
given that 2007 is one of the years in play wouldn't it  be better to include 2007 in your average and analysis.  Including 2007 lowers the average loss to 569k km^2 and a drop in line with that of 2007 would leave us in 6th place.

Having said that I am still happy with my  poll prediction of 2.5 - 2.75.

Well, in this case, the term 'better' seems subjective. How about 'different' instead? And in that case, yes, including 2007 would produce a different result than not including it. The same can be said, of course, about 2006, or 2005, or 2004, or 1997, or 1986, or any other year. Using 2008 onward, then, was a simple judgement call, one intended to avoid having 2007's weirdness skew the results either way...

DavidR

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Re: 2015 sea ice area and extent data
« Reply #888 on: August 19, 2015, 06:16:36 AM »
Jim,
given that 2007 is one of the years in play wouldn't it  be better to include 2007 in your average and analysis.  Including 2007 lowers the average loss to 569k km^2 and a drop in line with that of 2007 would leave us in 6th place.

Having said that I am still happy with my  poll prediction of 2.5 - 2.75.

Well, in this case, the term 'better' seems subjective. How about 'different' instead? And in that case, yes, including 2007 would produce a different result than not including it. The same can be said, of course, about 2006, or 2005, or 2004, or 1997, or 1986, or any other year. Using 2008 onward, then, was a simple judgement call, one intended to avoid having 2007's weirdness skew the results either way...
I think the difference is that (as at 17th August) 2006 would not  be in the lowest 10 years and no other year before 2007 would be in the lowest 8 but  2007 sits at second and is clearly part of the current group of low ice years. 

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #889 on: August 19, 2015, 12:47:00 PM »
ADS-NIPR Extent:
5,328,130 km2 (18 August)
Down 8,613,930 km2 (61.78%) from 2015 maximum of 13,942,060 km2 on 15 February.
2,150,675 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 91,717 km2 (-1.69%) from previous day.
Down 394,502 km2  (-6.89%) over past seven days (daily average: -56,357 km2).
Down 1,235,732 km2  (-18.83%) for August (daily average: -68,652 km2).
848,733 km2 below 2000s average for this date.
51,313 km2 above 2010s average for this date.
346,731 km2 below 2014 value for this date.
1,021,922 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
64 days this year (27.83% year-to-date) have recorded the lowest daily extent.
32 days (13.91%) have recorded the second lowest.
32 days (13.91%) have recorded the third lowest.
128 days (55.65%) 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.
3,454,562 km2 (19 August [Day 0.6301])
Down 9,819,993 km2 (73.98%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
1,220,553 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 56,782 km2 (-1.62%) from previous day.
Down 215,687 km2 (-5.88%) over past seven days (daily average: -30,812 km2).
Down 958,467 km2 (-21.72%) for August (daily average: -50,446 km2).
868,428 km2 below 2000s average for this date.
203,037 km2 below 2010s average for this date.
1,041,188 km2 below 2014 value for this date.
577,103 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
7 days this year (3.03% year-to-date) have recorded the lowest daily area.
19 days (8.23%) have recorded the second lowest.
30 days (12.99%) have recorded the third lowest.
56 days in total (24.24%) have been among the lowest three on record.
« Last Edit: August 19, 2015, 08:37:23 PM by Jim Pettit »

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #890 on: August 19, 2015, 03:17:06 PM »
Difference between today's ADR-NIPR SIE and previous years final minimum

18 August, 2015 SIE - 5,328,130 KM2

Year      Day     SIE Minimum     +/- Todays SIE
2003   15-Sep     5,937,087       (608,957)
2004   11-Sep     5,683,663       (355,533)
2006   14-Sep     5,625,046       (296,916)

2005   21-Sep     5,179,300         148,830
2009   12-Sep     5,054,055         274,075
2014   12-Sep     4,884,120         444,010
2013   12-Sep     4,809,288         518,842
2010   17-Sep     4,622,092         706,038
2008   9-Sep       4,500,623         827,507
2011   10-Sep     4,269,199      1,058,931
2007   17-Sep     4,065,759      1,262,371
2012   16-Sep     3,177,455      2,150,675

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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #891 on: August 19, 2015, 03:35:02 PM »
Difference between today's ADR-NIPR SIE and previous years final minimum

18 August, 2015 SIE - 5,328,130 KM2

Year      Day     SIE Minimum     +/- Todays SIE
2003   15-Sep     5,937,087       (608,957)
2004   11-Sep     5,683,663       (355,533)
2006   14-Sep     5,625,046       (296,916)

2005   21-Sep     5,179,300         148,830
2009   12-Sep     5,054,055         274,075
2014   12-Sep     4,884,120         444,010
2013   12-Sep     4,809,288         518,842
2010   17-Sep     4,622,092         706,038
2008   9-Sep       4,500,623         827,507
2011   10-Sep     4,269,199      1,058,931
2007   17-Sep     4,065,759      1,262,371
2012   16-Sep     3,177,455      2,150,675



Thanks, OLN. The average remaining ADR-NIPR SIE decrease from now until minimum for the past ten years:

2014: 791k
2013: 790k
2012: 1,129k
2011: 886k
2010: 975k
2009: 852k
2008: 1,091k
2007: 929k
2006: 479k
2005:  714k
-------------
AVRG: 863k

If the rest of the year follows the 10-year average trajectory, then, 2015 will end up in 4th place, just ahead of 2008. Overtaking 2011 for 3rd is reachable, but not likely; and 5th place is still a real possibility. So, as with all other sea ice metrics: we'll have to watch and wait...

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Re: 2015 sea ice area and extent data
« Reply #892 on: August 19, 2015, 04:31:32 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):

day   chg  estimate  CT-value
Wed        3.512301  3.511344
Thu -59.5  3.452810  -
Fri -57.1  3.395717  -

Cooperating regio's are CAB (-26k8), CAA (-18k7) and Laptev (-11k9)

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 #893 on: August 19, 2015, 05:19:20 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):

day   chg  estimate  CT-value
Wed        3.512301  3.511344
Thu -59.5  3.452810  -
Fri -57.1  3.395717  -

Cooperating regio's are CAB (-26k8), CAA (-18k7) and Laptev (-11k9)

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).

Thanks, Wipneus. That moves 2015 SIA ahead of 2014, and into 6th place. If the remainder of the melt season follows the trajectories of 2014, 2012, 2010, or 2008, 2015 will end up in 2nd place, while copying the ending behavior of 2013 or 2011 would leave 2015 in 5th, while copying 2009 would leave this year in 4th.

Here's an updated list of how much further CT area needs to fall to move into each of the six remaining ranks:

5th   324k
4th   393k
3rd   477k
2nd   491k
1st   1,162k

There is, obviously, a ways to go before 2015 can move into the 5th place spot currently held by 2010. But note that the average to-minimum loss from this day forward over the past ten years has been 466k, while over the past five years that's been 583k. Meaning, one supposes, that while first place is out of the running, 2nd through 5th places are all up for grabs.

Bill Fothergill

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Re: 2015 sea ice area and extent data
« Reply #894 on: August 19, 2015, 06:06:13 PM »


Bill, welcome to the forum.

This usually (always until now) gets corrected. Note that the 3.612 is probably correct for the Monday data release, but the average value (last column) is the value for Sunday!

Thanks for the welcome :)

I had noticed that the Average figure had stepped by the appropriate value, so it did look like a simple data-drop. As at today, the "jitter" has been picked up by  the team at UIUC and the 3 datasets (Arctic, Antarctic, Global) look back in sync.

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #895 on: August 20, 2015, 03:10:33 AM »


Difference between today's ADR-NIPR SIE and previous years final minimum

18 August, 2015 SIE - 5,328,130 KM2

Year      Day     SIE Minimum     +/- Todays SIE
2003   15-Sep     5,937,087       (608,957)
2004   11-Sep     5,683,663       (355,533)
2006   14-Sep     5,625,046       (296,916)

2005   21-Sep     5,179,300         148,830
2009   12-Sep     5,054,055         274,075
2014   12-Sep     4,884,120         444,010
2013   12-Sep     4,809,288         518,842
2010   17-Sep     4,622,092         706,038
2008   9-Sep       4,500,623         827,507
2011   10-Sep     4,269,199      1,058,931
2007   17-Sep     4,065,759      1,262,371
2012   16-Sep     3,177,455      2,150,675



Thanks, OLN. The average remaining ADR-NIPR SIE decrease from now until minimum for the past ten years:

2014: 791k
2013: 790k
2012: 1,129k
2011: 886k
2010: 975k
2009: 852k
2008: 1,091k
2007: 929k
2006: 479k
2005:  714k
-------------
AVRG: 863k

If the rest of the year follows the 10-year average trajectory, then, 2015 will end up in 4th place, just ahead of 2008. Overtaking 2011 for 3rd is reachable, but not likely; and 5th place is still a real possibility. So, as with all other sea ice metrics: we'll have to watch and wait...

Jim,

I will update that table every time 2015 goes below another one of the previous years or if it's at least a week since I last posted it.  There is no sense in posted this info on a daily basis.

Now back to other issues related to 2015.  I've noticed on this topic and other topics on the Forum about the chances that 2015 will have an extended melting season, based on SST anomalies and the current El-Nino.  While those facts are true, I can only paraphrase what Neven said in today's ASIB post.  The end of the season's melting is almost entirely dependent on the winds in the Arctic regions. If they blow from the right direction, extent losses will accelerate. If they blow from
the wrong direction, extent losses will slow down rapidly.  The only way SSTs and El-Nino can impact this years melting is if the winds are blowing favorably to melt the most vulnerable ice.  In order to  go lower than 2011 and maybe 2007, it will probably take massive losses (~500K Km2), in September, like 2010.  Other that those  scenarios 2015 will end up 4th (or 5th).
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greatdying2

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Re: 2015 sea ice area and extent data
« Reply #896 on: August 20, 2015, 06:02:52 AM »
Maybe you should take a look at volume....:

Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.

Taking a step or three back from the daily Arctic horse race(s), I think this volume vs. area/extent relationship will continue to be the norm. 

To add to this, your sudden disappearance seems possible if the sea ice is of more or less constant thickness and it gradually thins over the years then suddenly it all disappears. However the reality is that the ice is more wedge shaped getting thinner towards the edges so you lose area as well as thickness over time.

Except we have a good counter-example this year in Beaufort, which melted from the inside out, seemingly due to strips of thick and thin ice. What if this happens again but more extensively, shredding the pack into ribbons and greatly increasing the edge length? Seems like it could lead to a rapid increase in melt rate.
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Re: 2015 sea ice area and extent data
« Reply #897 on: August 20, 2015, 12:59:51 PM »
Maybe you should take a look at volume....:

Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.

Taking a step or three back from the daily Arctic horse race(s), I think this volume vs. area/extent relationship will continue to be the norm. 

To add to this, your sudden disappearance seems possible if the sea ice is of more or less constant thickness and it gradually thins over the years then suddenly it all disappears. However the reality is that the ice is more wedge shaped getting thinner towards the edges so you lose area as well as thickness over time.

Except we have a good counter-example this year in Beaufort, which melted from the inside out, seemingly due to strips of thick and thin ice. What if this happens again but more extensively, shredding the pack into ribbons and greatly increasing the edge length? Seems like it could lead to a rapid increase in melt rate.

I think there is at least a couple of things mixed up in what I am trying to say:
1. The trend will be a slow approach towards low or zero ice in a year. This is Chris Reynolds 'slow transition', and

2. As we get closer to negligible ice free minimums, area will decrease at roughly same rate as thickness unlike the recent past where thickness has declined at a faster rate than area. The past involves lots of MYI thinning and disappearance which can be different to situation with FYI. In addition, there is consideration of distribution of size and shape of the ice.

Your 'good counter-example' does not appear to have caused all that low a level of ice this year so it isn't a brilliant counter-example.

With a trend of slow approach towards zero ice, you can still get the odd exceptional year which might give a surprise rapid drop to zero or close to it and yet only be a single year such that it doesn't affect the trend much. What you are suggesting happening once in a while seems quite possible perhaps likely if given enough chances/times to occur. This would seem like it could just be such an odd exceptional year but not really changing the slow approach trend.

Happening extensively and also repeatedly seems to me to be possible for several years near or after the trend has reached negligible levels so I am thinking probably not for a while yet because most years have seen a pattern where winds and gyre have kept the pack reasonably contiguous. Also there is the effect of edges melting more quickly due to wave action, temperature of water not surrounded by ice tending to be warmer and warmer air temperatures if winds have not travelled over ice. Therefore this year seems to me to be more likely to be an exception than the start of a new pattern.

Therefore I don't see this possibility as refuting what I was saying unless it starts happening extensively, repeatedly and soon which I don't think is likely.  But who knows, maybe it will start happening.

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Re: 2015 sea ice area and extent data
« Reply #898 on: August 20, 2015, 01:50:36 PM »

Difference between today's ADR-NIPR SIE and previous years final minimum

18 August, 2015 SIE - 5,328,130 KM2

Year      Day     SIE Minimum     +/- Todays SIE
2003   15-Sep     5,937,087       (608,957)
2004   11-Sep     5,683,663       (355,533)
2006   14-Sep     5,625,046       (296,916)

2005   21-Sep     5,179,300         148,830
2009   12-Sep     5,054,055         274,075
2014   12-Sep     4,884,120         444,010
2013   12-Sep     4,809,288         518,842
2010   17-Sep     4,622,092         706,038
2008   9-Sep       4,500,623         827,507
2011   10-Sep     4,269,199      1,058,931
2007   17-Sep     4,065,759      1,262,371
2012   16-Sep     3,177,455      2,150,675



Thanks, OLN. Thanks Jim. Discounting the last two measures that are obviously wrong (in the style of denialists) and the first two since 2007 hadn't happened yet gives the average to be

2012: 1,129k
2011: 886k
2010: 975k
2009: 852k
2008: 1,091k
2007: 929k

-------------
AVRG: 977k

Thus placing 2015 firmly in the 4th place with some possibilities to become the third. First it won't be unless something horrendous happens.
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Re: 2015 sea ice area and extent data
« Reply #899 on: August 20, 2015, 02:20:27 PM »
Maybe you should take a look at volume....:

Point taken. From a volume standpoint, this year looks a lot worse than it does versus area and extent.

Taking a step or three back from the daily Arctic horse race(s), I think this volume vs. area/extent relationship will continue to be the norm. 

To add to this, your sudden disappearance seems possible if the sea ice is of more or less constant thickness and it gradually thins over the years then suddenly it all disappears. However the reality is that the ice is more wedge shaped getting thinner towards the edges so you lose area as well as thickness over time.

Except we have a good counter-example this year in Beaufort, which melted from the inside out, seemingly due to strips of thick and thin ice. What if this happens again but more extensively, shredding the pack into ribbons and greatly increasing the edge length? Seems like it could lead to a rapid increase in melt rate.

I think there is at least a couple of things mixed up in what I am trying to say:
1. The trend will be a slow approach towards low or zero ice in a year. This is Chris Reynolds 'slow transition', and

2. As we get closer to negligible ice free minimums, area will decrease at roughly same rate as thickness unlike the recent past where thickness has declined at a faster rate than area. The past involves lots of MYI thinning and disappearance which can be different to situation with FYI. In addition, there is consideration of distribution of size and shape of the ice.

Your 'good counter-example' does not appear to have caused all that low a level of ice this year so it isn't a brilliant counter-example.

Yeah well, personally I'm not at all convinced that the approach to effectively zero ice will be slow. Once the thick ice is melted, that (ever increasing) heat will become available to melt the thin ice even faster. Rather than a slow approach, that would seem far more likely to cause the opposite: an acceleration of area and extent losses.

My counter example was in relation to your "wedge" premise. The area in which it occurred actually did suddenly melt on a large scale. It created its own edge from within the pack and then melting outwards in both directions along it. Thus it seems to contradict your wedge melt premise. But perhaps I misunderstand that premise.

In any case, this event happened without being predicted or as far as I have seen being well explained. Imagine something similar happening again, but on an even larger scale.

Just because we haven't seen it happen before, doesn't mean it might not be just around the corner. This is a highly complex, poorly understood system that is undergoing rapid change. No one should be confident of predictions.

Who knows? Indeed.
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.