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Buddy

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Re: 2015 sea ice area and extent data
« Reply #900 on: August 20, 2015, 03:12:13 PM »
Quote
Yeah well, personally I'm not at all convinced that the approach to effectively zero ice will be slow.

Once the volume gets so low....it would "seem" that it could go PDQ (pretty damn quick)...especially if it is spread out and without much thickness.

By the way....those two graphics you posted of August 4th and 19th are a pretty good "visual" of just how quickly things can go.
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Lou

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Re: 2015 sea ice area and extent data
« Reply #901 on: August 20, 2015, 03:42:00 PM »
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.

This may be the most accurate thing I've ever read on this site.

We are waaaaay out on the edge of our mental map re:theArctic, well into the "Here be dragons" area.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #902 on: August 20, 2015, 04:10:41 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
Thu        3.452810  3.448225
Fri -57.4  3.395408  -
Sat +44.5  3.439859  -

The CAB keeps dominating the daily changes, this time with a +57k3 increase. All very quiet elsewhere.

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).

seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #903 on: August 20, 2015, 04:31:45 PM »

Noting that SIE lost another century, now at 5.43 million km2.

From Wipneus' map above (much obliged), the Arm contributes its little bit to extent loss.

AmbiValent

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Re: 2015 sea ice area and extent data
« Reply #904 on: August 20, 2015, 04:35:06 PM »
I wonder whether the up and down is due to refreeze starting to balance the melting or whether that is just due to measuring problems.
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seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #905 on: August 20, 2015, 04:44:30 PM »
I wonder whether the up and down is due to refreeze starting to balance the melting or whether that is just due to measuring problems.
.
It is refreezing especially after surface melting of previous days,

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Re: 2015 sea ice area and extent data
« Reply #906 on: August 21, 2015, 04:23:51 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        3.395408  3.393833
Sat +44.9  3.440294  -
Sun +85.9  3.526231  -

Again the CAB is the region with most of the area action (+76k), helped by an increase of "lake ice" (+17k2).

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).

Bill Fothergill

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Re: 2015 sea ice area and extent data
« Reply #907 on: August 21, 2015, 07:55:12 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        3.395408  3.393833
Sat +44.9  3.440294  -
Sun +85.9  3.526231  -

Again the CAB is the region with most of the area action (+76k), helped by an increase of "lake ice" (+17k2).


Deja vu, or what?

Given the above rises over the next 2 days, that should mean that the CT SIA figure will only have dropped somewhere in the region of 60k between Days 224 - 233.

Rather reminiscent of last year's stall between Days 215 - 230, which saw a drop of only 150k.

'Tis a brave man - or woman - who thinks they know where 2015 is going to end up. (Well obviously, it's going to end up with the 31st of December, but that's not exactly what I had in mind.)   ;)

Tor Bejnar

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Re: 2015 sea ice area and extent data
« Reply #908 on: August 21, 2015, 08:36:46 PM »
December 31 - how culturally bound you are!   :o
There are so many calendars to choose from.  In some, 2015 ended a long time ago.  Nepal's Vikram Samvat calendar is over 56 years 'ahead' of the one our culture uses.  I think 2015 ended in what we would call April 1959.

So in Nepal, 2015 ended with lots of ice in the Arctic! :P
(Edit: was this also not what you had in mind?)
Arctic ice is healthy for children and other living things.

Bill Fothergill

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Re: 2015 sea ice area and extent data
« Reply #909 on: August 21, 2015, 09:13:52 PM »
how culturally bound you are!   :o


Well, you can't beat a bit of bondage. (I can't believe I've just typed that!)

By that measure, when I said "2015" or "215 - 230", I should really have confirmed that I was using denary, as opposed to octal, or Hex, or anything else for that matter.

 :-X

jdallen

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Re: 2015 sea ice area and extent data
« Reply #910 on: August 21, 2015, 09:37:38 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        3.395408  3.393833
Sat +44.9  3.440294  -
Sun +85.9  3.526231  -

Again the CAB is the region with most of the area action (+76k), helped by an increase of "lake ice" (+17k2).


Deja vu, or what?

Given the above rises over the next 2 days, that should mean that the CT SIA figure will only have dropped somewhere in the region of 60k between Days 224 - 233.

Rather reminiscent of last year's stall between Days 215 - 230, which saw a drop of only 150k.

'Tis a brave man - or woman - who thinks they know where 2015 is going to end up. (Well obviously, it's going to end up with the 31st of December, but that's not exactly what I had in mind.)   ;)

I'm suspicious of those numbers, but will reserve comment to see what follows.
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OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #911 on: August 22, 2015, 01:19:58 PM »
Another year bites the dust.

Today's drop of over 61K Km2 the ADR-NIPR SIE went below 2005's annual minimum.  At the current rate of loss, it won't be many days until we get below 2009.

Current SIE  21-Aug, 2015   5,137,974 KM2

Year      Day       SIE Minimum   +/- Todays SIE
2003   15-Sep     5,937,087        (799,113)
2004   11-Sep     5,625,046        (487,072)
2005   21-Sep     5,179,300        (41,326)

2009   12-Sep     5,054,055          83,919
2014   12-Sep     4,884,120        253,854
2013   12-Sep     4,809,288        328,686
2010   17-Sep     4,622,092        515,882
2008   9-Sep       4,500,623        637,351
2011   10-Sep     4,269,199        868,775
2007   17-Sep     4,065,759      1,072,215
2012   16-Sep     3,177,455      1,960,519
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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #912 on: August 22, 2015, 04:08:58 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        3.395408  3.393833
Sat +44.9  3.440294  -
Sun +86.2  3.526464  -
Mon +44.5  3.570962  -

The area increase in the CAB continues (+54k5), despite a loss in the Laptev region (-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 #913 on: August 22, 2015, 04:36:44 PM »
It's not at all unheard of to see such a large three-day increase in CT area in August, though it is unusual. The current 3-day rise of c. 177k is the largest August increase in a number of years. (By way of contrast, 2014 saw a decrease of 252k over the same period.)

Even after the increase, 2nd place is still reachable, though with decreasing chances. In fact, 2015 would have to mimic the behavior of 2014 or 2010 too get to second. A duplicate of 2009's to-minimum behavior would place 2015 in 4th; 2008- or 2012-like behavior would place us in 5th; and behavior like either 2011 or 2013 would leave 2015 in 6th, which is where it presently sits.

jdallen

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Re: 2015 sea ice area and extent data
« Reply #914 on: August 22, 2015, 07:05:06 PM »
It's not at all unheard of to see such a large three-day increase in CT area in August, though it is unusual. The current 3-day rise of c. 177k is the largest August increase in a number of years. (By way of contrast, 2014 saw a decrease of 252k over the same period.)

Even after the increase, 2nd place is still reachable, though with decreasing chances. In fact, 2015 would have to mimic the behavior of 2014 or 2010 too get to second. A duplicate of 2009's to-minimum behavior would place 2015 in 4th; 2008- or 2012-like behavior would place us in 5th; and behavior like either 2011 or 2013 would leave 2015 in 6th, which is where it presently sits.
All true.  I have confidence in Wipneus' numbers, but it's extremely perplexing.

The temp information doesn't suggest conditions supporting that level of increase.

(edit:  it also stands in contrast to the NSIDC SIA and IJIS SIE numbers, which are grinding downwards steadily at 40-90K/day)
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Peter Ellis

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Re: 2015 sea ice area and extent data
« Reply #915 on: August 22, 2015, 07:22:38 PM »
All true.  I have confidence in Wipneus' numbers, but it's extremely perplexing.

The temp information doesn't suggest conditions supporting that level of increase.

Yes it does.  The temperature across the majority of the ice pack is below zero (purple in your second image), as is typical for this time of year (white = zero anomaly in your first graph).  This means that surface melt has largely ceased, and all the melt ponds are beginning to freeze over across most of the pack in the high Arctic, with the remaining melt being bottom-melt at the fringes of the pack driven by warm waters.

(edit:  it also stands in contrast to the NSIDC SIA and IJIS SIE numbers, which are grinding downwards steadily at 40-90K/day)
NSIDC is also SIE, not SIA.  Extent is continuing to drop, as the fringe melts out.  Area is bottoming out as melt ponds freeze over.  Compactness will rise over the next few weeks.  This is absolutely normal for the time of year.

Buddy

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Re: 2015 sea ice area and extent data
« Reply #916 on: August 22, 2015, 07:58:12 PM »
Here's "another look".

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150821.png

You can see that volume per DMI has "started" at least a short term...if not long term.....turn UP.

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Richard Rathbone

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Re: 2015 sea ice area and extent data
« Reply #917 on: August 22, 2015, 08:30:14 PM »
This is normal for CICE based models. PIOMAS tends to keep going down into September but CICE tends to hit its minimum a month or so earlier. While you can look at PIOMAS at end August and expect its not quite mimimum yet, CICE volume probably has already passed it minimum.

jdallen

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Re: 2015 sea ice area and extent data
« Reply #918 on: August 22, 2015, 09:19:36 PM »
(edit:  it also stands in contrast to the NSIDC SIA and IJIS SIE numbers, which are grinding downwards steadily at 40-90K/day)
...NSIDC is also SIE, not SIA...
Ah, just so... I was conflating it with PIOMAS.  Blame the confusion on premature senility :P
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Neven

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Re: 2015 sea ice area and extent data
« Reply #919 on: August 23, 2015, 08:42:48 AM »
NSIDC is also SIE, not SIA.  Extent is continuing to drop, as the fringe melts out.  Area is bottoming out as melt ponds freeze over.  Compactness will rise over the next few weeks.  This is absolutely normal for the time of year.

It's normal for the time of year, but CAPIE is absolutely shooting through the roof:

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Nick_Naylor

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Re: 2015 sea ice area and extent data
« Reply #920 on: August 23, 2015, 02:52:58 PM »
It's normal for the time of year, but CAPIE is absolutely shooting through the roof:

I don't follow  :o If anything, in my mind that chart show only one year where anything like this has happened before - 2014, and in that case it was immediately reversed.

Peter Ellis

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Re: 2015 sea ice area and extent data
« Reply #921 on: August 23, 2015, 02:59:27 PM »
Look harder.  This year's line is almost exactly on top of 2012's. Other years with similar sharp jumps in CAPIE around this time of year include 2007, 2009 and 2011

Nick_Naylor

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Re: 2015 sea ice area and extent data
« Reply #922 on: August 23, 2015, 03:39:52 PM »
Actually, I misread Neven's comment. He wasn't saying it was normal for CAPIE to shoot through the roof, as I originally understood. Just normal for it to transition from declining to increasing.

The very few instances of similar quick large changes in the past have all represented short-term departures from a trend line. Expect CAPIE to revert to the 65-70 range within 5 days.

BornFromTheVoid

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Re: 2015 sea ice area and extent data
« Reply #923 on: August 23, 2015, 04:13:07 PM »
Update for the week to August 22nd

The current 5 day mean is on 5,381,600km2 while the 1 day extent is at 5,215,000km2.
The daily anomaly (compared to 81-10) is at -1,562,860km2, an increase from -1,461,340km2 last week. The anomaly compared to the 07, 11 and 12 average is at +543,067km2, an increase from +525,733km2 last week. We're currently 4th lowest on record, the same as last week.



The average daily change over the last 7 days was -65.8k/day, compared to the long term average of -51.3k/day, and the 07, 11 and 12 average of -68.3k/day.
The average long term change over the next week is -42.0k/day, with the 07, 11, and 12 average being -53.9k/day.



The loss so far this August is the 9th largest on record. To achieve the largest monthly drop, a daily loss of at least 123.2k/day is required, while the smallest drop requires an increase of more than 47.0k/day and an average drop requires a loss of 12.2k/day.

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

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #924 on: August 23, 2015, 04:21:43 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
Sun        3.526464  3.527725
Mon +44.5  3.570969  -
Tue +47.0  3.617941  -

The CAB tried to score a century gain (+92k5), but failed due to decline of "lake ice" (-23k1) and of ice  in Hudson (-16k9) and ESS (-11k1).

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).

Stephen

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Re: 2015 sea ice area and extent data
« Reply #925 on: August 24, 2015, 11:49:03 AM »
That's 4 consecutive days of increase.  Maybe we've seen the minimum.
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Peter Ellis

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Re: 2015 sea ice area and extent data
« Reply #926 on: August 24, 2015, 12:29:51 PM »
No chance.

AmbiValent

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Re: 2015 sea ice area and extent data
« Reply #927 on: August 24, 2015, 01:15:40 PM »
I think currently it's only the freshwater in melt ponds on the surface that is freezing. Meanwhile, bottom melt continues since the water is still warm enough. Saltwater will start to freeze in September, again starting from the center of the ice.
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OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #928 on: August 24, 2015, 01:48:56 PM »
ADS-NIPR SIE Update

It's another exciting day in the Arctic Sea Ice's race to oblivion.  2015 SIE is now below the annual minimum of 2009 and it is almost certain that it will go below 2013 and 2014 in the upcoming days as well as probably going below 2010 before the end of August. (See second table below for the difference between the current SIE and previous years annual minimum)

It is becoming more and more  likely that the 2015 SIE will finish no higher than 4th place by the end of the melt season.  The chances of finishing below 2011 for 3rd place is greater than finishing above 2008 in 5th place. (See first  table below for various projected loss scenarios)

It will take continuing record or near-record losses and a late finish for the melt season in order for the  2015 SIE to end  up below 2007.  However, it is no longer impossible to end up the year in 2nd place, just not a very wise bet. 





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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #929 on: August 24, 2015, 04:41:07 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        3.570969  3.571827
Tue +47.0  3.617943  -
Wed -19.7  3.598286  -

Back to the small declines perhaps, despite an increase of lake ice (+13k1). CAB showed a loss of -12k, other regions changed little.

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 #930 on: August 25, 2015, 05:38:50 PM »
NSIDC just updated their gridded sea ice concentration data from the 6th of August until yesterday. No dramatic changes AFAICS.

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Re: 2015 sea ice area and extent data
« Reply #931 on: August 25, 2015, 05:42:02 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        3.570969  3.571827
Tue +47.0  3.617943  -
Wed -19.7  3.598286  -
Thu -20.4  3.577931  -

The small decline was despite an increase in "lake" ice (+10k9). Laptev declined -15k5, other regions not much.

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).

seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #932 on: August 25, 2015, 05:50:03 PM »

Thank you Wipneus.
A lot of red around the Arm.

A century break in the NSIDC SIE. Leaving it just a tad above 5 million km2.

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Re: 2015 sea ice area and extent data
« Reply #933 on: August 25, 2015, 07:59:42 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        3.570969  3.571827
Tue +47.0  3.617943  -
Wed -19.7  3.598286  -
Thu -20.4  3.577931  -

The small decline was despite an increase in "lake" ice (+10k9). Laptev declined -15k5, other regions not much.

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).

So: CT SIA has--obviously--stalled, gaining 184k over the past six days, and losing less than 3k over the past 12 days.  By way of comparison, here are the sea ice area changes recorded during the same 12 day span for a few select years:

2014: -617k
2013: -362k
2012: -454k
2007: -491k

While it's still possible for 2015 to move up from current 6th place, it's increasingly unlikely at this point. In fact, of years from 2007 onward, only to-end behavior similar to 2010 would do so. IOW, while I wouldn't place any bets just yet--there are, after all, still three weeks left in the melt season--it looks as though sixth place it where 2015 will end up...




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Re: 2015 sea ice area and extent data
« Reply #934 on: August 25, 2015, 08:14:13 PM »
While it's still possible for 2015 to move up from current 6th place, it's increasingly unlikely at this point. In fact, of years from 2007 onward, only to-end behavior similar to 2010 would do so. IOW, while I wouldn't place any bets just yet--there are, after all, still three weeks left in the melt season--it looks as though sixth place it where 2015 will end up...

Points taken, but all of this is based entirely on looking at the past. Looking forward, the next few days have the potential to re-arrange the ice and stored energy quite noticeably.

Also, note that 2008 was nearly as high as 2015 around this date, so given the small sample it's not such a long shot even ignoring the forecast.

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #935 on: August 25, 2015, 09:17:16 PM »
Meanwhile ADS-NIPR is dropping like a rock, having lost  600,905 Km2 since the 15th of August, for a daily rate of 66,767 Km2.  It's only been 4 days since 2015 dropped below the annual minimum of 2005 and 2 days since it dropped below 2009. 

Looking ahead for the next week or so, if daily losses were to be 55k  Km2/day 2015 would drop below 2014 tomorrow (25th), 2013 two days later (27th), 2010 after another 3 days (30th) and 2008 after another 2 days (September 1st).

With the upcoming storms forecast for the Arctic and the SIE loss predictions of others commenters on the 2015 Melting Season topic, it seems quite possible that 2015 may start September in 4th place with reasonable chances of ending the season below 2011.  Going below 2007 will require well above average losses for the remainder of the season, however, it is no longer improbable. 

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epiphyte

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Re: 2015 sea ice area and extent data
« Reply #936 on: August 26, 2015, 06:04:22 AM »

So: CT SIA has--obviously--stalled, gaining 184k over the past six days, and losing less than 3k over the past 12 days. 

While it's still possible for 2015 to move up from current 6th place, it's increasingly unlikely at this point. [...]

...but look at wipneus' map. Every point on the perimeter of the ice sheet is red. That doesn't look like a stall to me; it looks like an indication that we're flirting with substantial collapse.

Look at the sentinel SAR images on the Atlantic side showing a totally amorphous surface all the way in to 84 degrees N, and large gaps in the ice sheet from laptev /kara down to >86 degrees N

Look at what Healy is reporting further west around 84 degrees - 30-60cm with very low resistance - i.e.slush.

Look at the SST maps - above zero almost all around the periphery.

Look at the weather forecast predicting a general stirring of the pot.

Yesterday I posted a comparison between 08/23 and 08/24 for obouy 9, showing CAB melt ponds which froze over during those 24 hours. That's what's causing the area increase - it is half-inch thick ice sitting on top of >30cm of liquid water sitting on top of  -well I don't know what, but it has no freeboard to speak of so it can't be much, and it won't be freezing hard for a at least a couple of weeks yet.

Meanwhile the edges are being relentlessly eroded. All in all if it doesn't end up in second or third, at least, IMO it will be by the skin of it's teeth...

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #937 on: August 26, 2015, 01:03:13 PM »
Another Year Bites the Dust!!

The ADS-NIPR SIE lost another 71K Km2 to go below 2014's annual minimum and we only need to lose another 42K Km2 to go below 2013's annual minimum.  At the current rate of losses, 2015 could easily go below 2010 before the end of August.

It's time to stock up on beer and snacks because we may have an exciting finish to the end of the melt season!!

Year      Day     SIE Minimum     +/- Todays SIE
2003   15-Sep     5,937,087       (1,086,124)
2004   11-Sep     5,683,663          (832,700)
2006   14-Sep     5,625,046          (774,083)
2005   21-Sep     5,179,300          (328,337)
2009   12-Sep     5,054,055          (203,092)
2014   12-Sep     4,884,120            (33,157)

2013   12-Sep     4,809,288              41,675
2010   17-Sep     4,622,092            228,871
2008   9-Sep       4,500,623            350,340
2011   10-Sep     4,269,199            581,764
2007   17-Sep     4,065,759            785,204
2012   16-Sep     3,177,455         1,673,508
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Richard Rathbone

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Re: 2015 sea ice area and extent data
« Reply #938 on: August 26, 2015, 01:26:22 PM »
Wipneus's map shows compaction rather than melt (and is based on UH rather than NSIDC). There's a lot of red round the outside because there's been a lot of compaction. The ice has been moving inwards a lot and melting rather less.

There's a lot of surface freeze still available to pull NSIDC area up higher. Its still some way below UH area and that gap is mainly down to wet ice/melt ponds being counted as open water.

See the graphs in the first post of the home brew thread. Extent dropped fast, area stalled, big upspike in compactness.

http://forum.arctic-sea-ice.net/index.php/topic,382.0.html

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #939 on: August 26, 2015, 02:43:28 PM »

So: CT SIA has--obviously--stalled, gaining 184k over the past six days, and losing less than 3k over the past 12 days. 

While it's still possible for 2015 to move up from current 6th place, it's increasingly unlikely at this point. [...]

...but look at wipneus' map. Every point on the perimeter of the ice sheet is red. That doesn't look like a stall to me; it looks like an indication that we're flirting with substantial collapse.

Look at the sentinel SAR images on the Atlantic side showing a totally amorphous surface all the way in to 84 degrees N, and large gaps in the ice sheet from laptev /kara down to >86 degrees N

Look at what Healy is reporting further west around 84 degrees - 30-60cm with very low resistance - i.e.slush.

Look at the SST maps - above zero almost all around the periphery.

Look at the weather forecast predicting a general stirring of the pot.

Yesterday I posted a comparison between 08/23 and 08/24 for obouy 9, showing CAB melt ponds which froze over during those 24 hours. That's what's causing the area increase - it is half-inch thick ice sitting on top of >30cm of liquid water sitting on top of  -well I don't know what, but it has no freeboard to speak of so it can't be much, and it won't be freezing hard for a at least a couple of weeks yet.

Meanwhile the edges are being relentlessly eroded. All in all if it doesn't end up in second or third, at least, IMO it will be by the skin of it's teeth...

I see what you're saying, but...2015 SIA is (by Wipneus' calculations) 3.577931M km2. If the melt season were to be over today, that's enough for 6th place. Now, in the following table, the five remaining rankings above 6th are listed, along with the year. The third column shows how much more ice was lost from this date through minimum for each of those years. The fourth column shows how much farther 2015 would have to fall to reach any of those spots.

5th      2010      571k      507k
4th      2008      235k      575k
3rd      2007      111k      660k
2nd      2011      79k      674k
1st      2012      409k      1,345k

Too, notice the very small separation between 6th and 2nd places. 6th place can be as low as 3.073M km2, while 2nd place can be as high as 2.905 km2--a total difference of only about 168k.

greatdying2

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Re: 2015 sea ice area and extent data
« Reply #940 on: August 26, 2015, 04:10:46 PM »
Another Year Bites the Dust!!

The ADS-NIPR SIE lost another 71K Km2 to go below 2014's annual minimum and we only need to lose another 42K Km2 to go below 2013's annual minimum.  At the current rate of losses, 2015 could easily go below 2010 before the end of August.

 :)  Or, to see it graphically (with NSIDC numbers, slightly different):
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 #941 on: August 26, 2015, 04:17:17 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        3.598286  3.597697
Thu -20.4  3.577931  -
Fri -34.7  3.543204  -

CAB (-11k8) and "lake ice" (-11k4) are the only significant contributors.

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).

TerryM

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Re: 2015 sea ice area and extent data
« Reply #942 on: August 26, 2015, 08:19:38 PM »
Keeping the Coriolis effect in mind the 65km winds flowing from the CAA towards Russia & the 35km winds sweeping from the ESAS toward the Laptev Sea should cause any ice to compact closer to the pole, or at least any ice that isn't melted by warm water being brought to the surface.    :)


Terry

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Re: 2015 sea ice area and extent data
« Reply #943 on: August 26, 2015, 08:39:01 PM »
I don't think we'll be seeing a lot of compaction.  This is a week out, but these two cyclones hitting the area after this one are really going to mess things up.   
FNORD

TerryM

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Re: 2015 sea ice area and extent data
« Reply #944 on: August 26, 2015, 09:32:45 PM »
If the above lows do come to pass, things will spiral out of control    :)


I'd been working off today's nullschool figures.


Terry

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Re: 2015 sea ice area and extent data
« Reply #945 on: August 27, 2015, 01:38:43 PM »
ADS-NIPR Extent:
4,713,460 km2 (26 August)
Down 9,228,600 km2 (66.19%) from 2015 maximum of 13,942,060 km2 on 15 February.
1,536,005 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 137,503 km2 (-2.83%) from previous day.
Down 534,615 km2  (-10.19%) over past seven days (daily average: -76,374 km2).
Down 1,850,402 km2  (-28.19%) for August (daily average: -71,169 km2).
1,121,300 km2 below 2000s average for this date.
120,863 km2 below 2010s average for this date.
565,664 km2 below 2014 value for this date.
1,031,853 km2 above 2012 value for this date.
4th lowest August to-date average.
3rd lowest value for the date.
64 days this year (26.89% year-to-date) have recorded the lowest daily extent.
32 days (13.45%) have recorded the second lowest.
33 days (13.87%) have recorded the third lowest.
129 days (54.2%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent/inconsistent 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.
3,543,204 km2 (27 August [Day 0.6521])
Down 9,731,351 km2 (73.31%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
1,309,195 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 34,585 km2 (-.97%) from previous day.
Up 149,371 km2 (4.4%) over past seven days (daily average: 21,339 km2).
Down 869,825 km2 (-19.71%) for August (daily average: -32,216 km2).
579,289 km2 below 2000s average for this date.
114,457 km2 above 2010s average for this date.
423,357 km2 below 2014 value for this date.
948,712 km2 above 2012 value for this date.
4th lowest August to-date average.
5th lowest value for the date.
7 days this year (2.93% year-to-date) have recorded the lowest daily area.
19 days (7.95%) have recorded the second lowest.
30 days (12.55%) have recorded the third lowest.
56 days in total (23.43%) have been among the lowest three on record.

« Last Edit: August 27, 2015, 01:44:26 PM by Jim Pettit »

OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #946 on: August 27, 2015, 02:26:28 PM »
With today's drop of 137K, it is now very likely that 2015 will finish this season no higher than third.  And if this current storm continues the damage in the  Beaufort Sea, there is a reasonable chance that 2015 will be in second place and might dip below 4M Km2.






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Re: 2015 sea ice area and extent data
« Reply #947 on: August 27, 2015, 03:43:43 PM »
I wonder if there will be a double century break in extent reported in a few minutes . . .

 ::)

-80k

 :-X
« Last Edit: August 27, 2015, 03:57:47 PM by seaicesailor »

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Re: 2015 sea ice area and extent data
« Reply #948 on: August 27, 2015, 04:38:22 PM »
Again NSIDC updated its gridded sea ice concentration data from 6-26 Aug. Some differences, nothing dramatic.

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
Thu        3.577931  3.577789
Fri -34.6  3.543364  -
Sat -45.9  3.497437  -

Contributions from the CAB (-29k9) and Beaufort (-16k9). The CAA increased by +10k8.

By extent the changes in these regions are somewhat bigger: Beaufort: -49k5, CAB: -41k5, CAA :+45k3.

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 #949 on: August 28, 2015, 02:34:04 PM »
With that second consecutive century drop, the current ADS-NIPR SIE is 4,584,969 Km2.  We are very closer to going below the annual minimum of 2008, which will certainly happen in the  next day or two.  As of today, 2015 is 146,253 Km2 below 2011 and only 16,567 Km2 above 2007.  The table below shows the difference between today's SIE and the annual minimums for previous years.  2007 is no longer safe from being surpassed this year.


Year    Day        SIE Minimum     +/- Todays SIE
2010   17-Sep    4,622,092           (37,123)
2008   9-Sep      4,500,623             84,346
2011   10-Sep    4,269,199            315,770
2007   17-Sep    4,065,759            519,210
2012   16-Sep    3,177,455           1,407,514
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