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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #750 on: July 26, 2015, 04:07:35 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Fri       5.072222
Sat -43.6  5.028612
Sun -86.9  4.941706
Mon -183.1  4.758563
Tue -85.0  4.673542

Support mostly by CAB (-46k), then nothing and then Laptev and Hudson ( both -13k).

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 #751 on: July 26, 2015, 04:30:26 PM »
Update for the week to July 25th

The current 5 day mean is on 7,553,400km2 while the 1 day extent is at 7,320,000km2.
The daily anomaly (compared to 81-10) is at -1,306,980km2, an increase from -1,052,840km2 last week. The anomaly compared to the 07, 11 and 12 average is at +438,553km2, a decrease from +754,867km2 last week. We're currently 6th lowest on record, up from 7th last week.



The average daily change over the last 7 days was -125.5k/day, compared to the long term average of -89.0k/day, and the 07, 11 and 12 average of -80.2k/day.
The average long term change over the next week is -85.1k/day, with the 07, 11, and 12 average being -76.7k/day.



The loss so far this July is the 5th largest on record. To achieve the largest monthly drop, a daily loss of at least 148.1k/day is required, while the smallest drop requires an increase of at least 102.9k/day and an average drop requires a loss of 6.4k/day.


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Re: 2015 sea ice area and extent data
« Reply #752 on: July 26, 2015, 11:44:25 PM »
Stands a good chance of finishing 4th.

DavidR

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Re: 2015 sea ice area and extent data
« Reply #753 on: July 27, 2015, 04:07:19 PM »
A 15k uptick on NSIDC extent today. I  suspect its just  windy.   I  can't wait to see what the area does.
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Re: 2015 sea ice area and extent data
« Reply #754 on: July 27, 2015, 04:10:07 PM »
NSIDC Daily Extent:

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

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361k
2012,    07,  22,      7.184,  -113k....2015,     07,   23,     7.548,   -110k.....+364k
2012,    07,  23,      7.118,   -66k.....2015,     07,  24,      7.434,   -114k.....+316k
2012,    07,  24,      7.035,   -83k.....2015,     07,  25,      7.320,   -114k.....+285k
2012,    07,  25,      6.931,  -104k....2015,     07,  26,      7.335,   + 15.......+404
2012,    07,  26,      6.809,  -122k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #755 on: July 27, 2015, 05:32:25 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Sun       4.942303
Mon -183.1  4.759160
Tue -85.0  4.674158
Wed -54.4  4.619771

The Wednesday's decline was mainly caused by a -30k5 decline in the CAB, with a -12k3 hand from Kara. Only small ++ and -- in other regions.

Curiously extent increased (calculated by the NSIDC method) by the same regions: CAB (+2k6) and Kara (+21k3). Here Hudson and Laptev need to be mentioned, canceling each other with a +14k4  and -14k1 respectively.

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

jdallen

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Re: 2015 sea ice area and extent data
« Reply #756 on: July 27, 2015, 05:37:51 PM »
A 15k uptick on NSIDC extent today. I  suspect its just  windy.   I  can't wait to see what the area does.
Indeed, absolutely some dispersion; a grab from earth.nullschool.net surface winds suggests it.

Area probably is still dropping much as it has been - 80-120K KM2/day.
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BornFromTheVoid

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Re: 2015 sea ice area and extent data
« Reply #757 on: July 27, 2015, 07:15:05 PM »
The 5 day mean NSIDC extent has just dipped below the 1980 September minimum and is within 500k of 7 other minima.


Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #758 on: July 27, 2015, 09:37:45 PM »
The 5 day mean NSIDC extent has just dipped below the 1980 September minimum and is within 500k of 7 other minima.

...And while we're at it: according to Wipneus' calculations, CT SIA has dropped below the minima recorded from 1980-1990, plus those recorded in 1992, 1994, 1996, and 1997. Next three on deck: 2001, 1993, and 1991, all of which should be overtaken sometime in the next four or five days.

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #759 on: July 28, 2015, 01:04:40 PM »
ADS-NIPR Extent:
6,843,550 km2 (27 July)
Down 7,098,510 km2 (50.91%) from 2015 maximum of 13,942,060 km2 on 15 February.
3,666,095 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 75,329 km2 (-1.09%) from previous day.
Down 678,958 km2  (-9.03%) over past seven days (daily average: -96,994 km2).
Down 2,638,766 km2  (-27.83%) for July (daily average: -97,732 km2).
793,791 km2 below 2000s average for this date.
58,948 km2 above 2010s average for this date.
254,357 km2 below 2014 value for this date.
477,432 km2 above 2012 value for this date.
7th lowest July to-date average.
4th lowest value for the date.
64 days this year (30.77% year-to-date) have recorded the lowest daily extent.
32 days (15.38%) have recorded the second lowest.
32 days (15.38%) have recorded the third lowest.
128 days (61.54%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
4,619,771 km2 (28 July [Day 0.5698])
Down 8,654,784 km2 (65.2%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,385,762 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 53,771 km2 (-1.15%) from previous day.
Down 573,269 km2 (-11.04%) over past seven days (daily average: -81,896 km2).
Down 2,835,050 km2 (-38.03%) for July (daily average: -101,252 km2).
785,102 km2 below 2000s average for this date.
66,436 km2 below 2010s average for this date.
513,022 km2 below 2014 value for this date.
320,666 km2 above 2012 value for this date.
5th lowest July to-date average.
4th lowest value for the date.
7 days this year (3.35% year-to-date) have recorded the lowest daily area.
19 days (9.09%) have recorded the second lowest.
29 days (13.88%) have recorded the third lowest.
55 days in total (26.32%) have been among the lowest three on record.

Vergent

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Re: 2015 sea ice area and extent data
« Reply #760 on: July 28, 2015, 03:53:05 PM »
NSIDC Daily Extent:

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

2012,    07,  14,      7.868..............2015,     07,  15,      8.615,   -131k.....+747k
2012,    07,  15,      7.705,  -163k....2015,     07,  16,      8.403,   -212k
2012,    07,  16,      7.606,   -99k.....2015,     07,  17,      8.271,   -132k
2012,    07,  17,      7.481,  -125k....2015,     07,  18,      8.120,   -151k
2012,    07,  18,      7.420,   -61k.....2015,     07,  19,      7.932,   -188k
2012,    07,  19,      7.350,   -70k.....2015,     07,  20,      7.903,   - 29k
2012,    07,  20,      7.340,   -10k.....2015,     07,  21,      7.807,   - 96k
2012,    07,  21,      7.297,  -113k....2015,     07,  22,      7.658,   -149k.....+361k
2012,    07,  22,      7.184,  -113k....2015,     07,   23,     7.548,   -110k.....+364k
2012,    07,  23,      7.118,   -66k.....2015,     07,  24,      7.434,   -114k.....+316k
2012,    07,  24,      7.035,   -83k.....2015,     07,  25,      7.320,   -114k.....+285k
2012,    07,  25,      6.931,  -104k....2015,     07,  26,      7.335,   + 15.......+404k
2012,    07,  26,      6.809,  -122k....2015,     07,  27,      7.236,    - 99.......+427k
2012,    07,  27,      6.677,  -132k
2012,    07,  28,      6.600,   -77k
2012,    07,  29,      6.478,  -122k
2012,    07,  30,      6.400,   -78k
2012,    07,  31,      6.368,   -32k

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Wipneus

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Re: 2015 sea ice area and extent data
« Reply #761 on: July 28, 2015, 04:12:31 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):

Tue       4.674303
Wed -54.4  4.619916
Thu -57.1  4.562800

Thursday's half century was brought to you by the CAB (-16k), Hudson (-14k) and Baffin (-11k).

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 #762 on: July 29, 2015, 04:23:08 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):

Tue       4.674303
Wed -54.4  4.619916
Thu -57.2  4.562677
Fri -30.0  4.532652

Frisday's 30k includes a -18k2 by the Hudson, offset by a +12k7 from Baffin and lots of little contributions (5-8k) from other regions.

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).

Sourabh

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Re: 2015 sea ice area and extent data
« Reply #763 on: July 29, 2015, 04:35:03 PM »
Wipneus,

Is it a temporary slowdown or does it look similar to what 2013 and 2014 experienced around the same time ?

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #764 on: July 29, 2015, 05:51:24 PM »
Wipneus,

Is it a temporary slowdown or does it look similar to what 2013 and 2014 experienced around the same time ?

Sorry that I cannot tell you what is going to happen. Some increase again is quite likely (that uptick in the Baffin will surely come back), but as you say a slow down is normal.
On the other hand we have seen it before when that did not happen and instead of a slowdown it went up! Now how likely (or even possible ) is that?

In the 2012 animation the blue's are area in melting, deeper blue mean more melting by area.

« Last Edit: July 29, 2015, 05:56:27 PM by Wipneus »

Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #765 on: July 29, 2015, 09:50:54 PM »
Wipneus,

Is it a temporary slowdown or does it look similar to what 2013 and 2014 experienced around the same time ?

That's a huge question. Day 0.5753--30 July-- was the last day 2014's late-July plateau; SIA dropped 54k over the following five days before entering a two-week period with a total decrease of just 114k (followed by an eight-day loss of 587k).  For 2013, Day 0.5753 marked the halfway spot of the eight-day 82k increase, which was followed by a ten-day loss of 683k. And, of course, on Day 0.5781, 2012 began a remarkable GAC-aided 12-day period that saw a loss of 1.14 million.

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Re: 2015 sea ice area and extent data
« Reply #766 on: July 30, 2015, 02:47:12 AM »
Jim,
not happening this year....



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slow wing

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Re: 2015 sea ice area and extent data
« Reply #767 on: July 30, 2015, 08:36:26 AM »
Those two graphs are comparing apples to oranges, or - to be more accurate - browns to oranges.

The colour scale is completely different between the two plots.

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Re: 2015 sea ice area and extent data
« Reply #768 on: July 30, 2015, 08:39:05 AM »
Here are just apples, from the latest ASI update on the blog:

Quote
Things continue to heat up everywhere, although I expected much more heat on the Pacific side of the Arctic, given the situation two weeks ago when SST anomaly was off the scale in that part of the Arctic. Still, it's comparable to the situation on July 28th 2012, August 4th 2014 (ie one week from now), and much, much warmer than July 26th 2014:




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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #769 on: July 30, 2015, 12:57:06 PM »
ADS-NIPR Extent:
6,730,052 km2 (29 July)
Down 7,212,008 km2 (51.73%) from 2015 maximum of 13,942,060 km2 on 15 February.
3,552,597 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 63,818 km2 (-.94%) from previous day.
Down 571,840 km2  (-7.83%) over past seven days (daily average: -81,691 km2).
Down 2,752,264 km2  (-29.03%) for July (daily average: -94,906 km2).
740,857 km2 below 2000s average for this date.
83,866 km2 above 2010s average for this date.
163,436 km2 below 2014 value for this date.
527,019 km2 above 2012 value for this date.
7th lowest July to-date average.
5th lowest value for the date.
64 days this year (30.48% year-to-date) have recorded the lowest daily extent.
32 days (15.24%) have recorded the second lowest.
32 days (15.24%) have recorded the third lowest.
128 days (60.95%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
4,532,652 km2 (30 July [Day 0.5753])
Down 8,741,903 km2 (65.85%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,298,643 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 30,148 km2 (-.66%) from previous day.
Down 539,570 km2 (-10.64%) over past seven days (daily average: -77,081 km2).
Down 2,922,169 km2 (-39.2%) for July (daily average: -97,406 km2).
754,312 km2 below 2000s average for this date.
66,915 km2 below 2010s average for this date.
655,532 km2 below 2014 value for this date.
296,785 km2 above 2012 value for this date.
5th lowest July to-date average.
5th lowest value for the date.
7 days this year (3.32% year-to-date) have recorded the lowest daily area.
19 days (9.%) have recorded the second lowest.
29 days (13.74%) have recorded the third lowest.
55 days in total (26.07%) have been among the lowest three on record.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #770 on: July 30, 2015, 04:33:01 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):

Thu       4.562689
Fri -30.1  4.532572
Sat -119.4  4.413175

Saturday's century is mostly the result of the CAB (-63k4). Smaller contributions from Baffin(-17k), CAA (-15k) and Laptev (-14k).

Some of the concentration drop seems to align with the heating over the north of CAA and the bordering CAB.

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

Neven

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Re: 2015 sea ice area and extent data
« Reply #771 on: July 30, 2015, 04:43:54 PM »
If I'm not mistaken that's this year's 43rd century break, just as much as 2013 at this point, and one more than 2012. But 2012 saw 5 CBs in August, and 2013 only 2.

This century break will cause another drop on CAPIE.
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Re: 2015 sea ice area and extent data
« Reply #772 on: July 30, 2015, 04:59:05 PM »
Notably, area is now less than 200k above the 2012 value. Given that we are still offset by slightly more than that in Hudson and Baffin, I'd call that quite impressive  (though admittedly we are just before the big 2012 loss).

Also notable: We are now 20 days ahead of 2014, and 10 days ahead of 2013.

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Re: 2015 sea ice area and extent data
« Reply #773 on: July 30, 2015, 06:16:14 PM »
If I'm not mistaken that's this year's 43rd century break, just as much as 2013 at this point, and one more than 2012. But 2012 saw 5 CBs in August, and 2013 only 2.

This century break will cause another drop on CAPIE.

Using a slightly different metric: that's the 41st CB since this year's maximum, where 2012 had but 39 from its maximum through now. However--and this is probably somewhat telling--this year has had only two double century breaks since the maximum, while 2012 had counted seven by now.

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Re: 2015 sea ice area and extent data
« Reply #774 on: July 31, 2015, 04:17:55 AM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Thu       4.562689
Fri -30.1  4.532572
Sat -119.4  4.413175

Wondering if Sunday is going to be a big loss as well? Maybe even bigger? That is from looking at the trend in U.Bremen concentration maps, ending with the map for 30 July (which will correspond to Sunday's update, if I am understanding correctly).

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #775 on: July 31, 2015, 07:57:29 AM »

Wondering if Sunday is going to be a big loss as well? Maybe even bigger? That is from looking at the trend in U.Bremen concentration maps, ending with the map for 30 July (which will correspond to Sunday's update, if I am understanding correctly).

You understand correctly. Also in the latest updates of Uni Hamburg SIC, Jaxa SIC and ADS-NIPR AMSR2 thickness/melting , the slow down is nowhere to be found.

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Re: 2015 sea ice area and extent data
« Reply #776 on: July 31, 2015, 09:46:31 AM »

Wondering if Sunday is going to be a big loss as well? Maybe even bigger? That is from looking at the trend in U.Bremen concentration maps, ending with the map for 30 July (which will correspond to Sunday's update, if I am understanding correctly).

You understand correctly. Also in the latest updates of Uni Hamburg SIC, Jaxa SIC and ADS-NIPR AMSR2 thickness/melting , the slow down is nowhere to be found.

And compactness is still lowest too, everywhere except on CAPIE:

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Re: 2015 sea ice area and extent data
« Reply #777 on: July 31, 2015, 04:20:49 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Thu       4.562689
Fri -30.1  4.532572
Sat -119.3  4.413302
Sun -127.4  4.285889

So no slowdown on Sunday. The hardest hit is for CAB (-56k8). Kara, ESS , Baffin and CAA all contribute around -11k.

Remaining ice area of Hudson and Baffin regions is 194k (about normal for the 1981-2010 period).

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

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Re: 2015 sea ice area and extent data
« Reply #778 on: July 31, 2015, 04:38:39 PM »
According to my  figures that  puts SIA at  second lowest;  just  50K km^2 above 2012. and NSIDC compaction (SIA/SIE) at 4.3% below 2012.  (66.2% vs 61.9%).

That  suggests there is plenty of room for further rapid reductions.
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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #779 on: July 31, 2015, 06:05:14 PM »
According to my  figures that  puts SIA at  second lowest;  just  50K km^2 above 2012. and NSIDC compaction (SIA/SIE) at 4.3% below 2012.  (66.2% vs 61.9%).

That  suggests there is plenty of room for further rapid reductions.
Are you sure about that second place? Using Wipneus' numbers, my records show CT SIA as 4th place for Day 0.5835, 371k behind 2012:

2012: 3,915,334 km2
2011: 4,186,187 km2
2007: 4,270,627 km2
2015: 4,285,889 km2

OTOH, 2015 SIA is now a pretty comfortable 512k ahead of 2013, and a remarkable 728k km2 ahead of 2014. (So much for the "rebound").

My take: 2015 almost certainly won't catch 2012; at this point, that would require an further loss of greater thasn 2 million km2. But beating 2007 for second is a very real possibility at this point; to do so, we'd need to see another 1.37 million km2 of loss over the next six weeks or so, an average of roughly 35k per day. (For the record, 2007 lost 1.35 million km2 between now and that year's maximum; 2013 dropped by an additional 1.244 million; 2014 lost another 1.53 million; and 2012 squeezed out another 1.68 million.)


seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #780 on: July 31, 2015, 06:18:03 PM »
NDSIC SIE fell 140+
Singular
With all the mess in the Pacific side

plinius

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Re: 2015 sea ice area and extent data
« Reply #781 on: July 31, 2015, 06:34:40 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Thu       4.562689
Fri -30.1  4.532572
Sat -119.3  4.413302
Sun -127.4  4.285889

So no slowdown on Sunday. The hardest hit is for CAB (-56k8). Kara, ESS , Baffin and CAA all contribute around -11k.

Remaining ice area of Hudson and Baffin regions is 194k (about normal for the 1981-2010 period).

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).

aren't you one day off? Friday is day 210, and cryosphere shows 4.08 for day 212 in 2012, so the truth is between you two. Though of course I agree it is not probable that we catch 2012, given the very high losses 2012 showed over the next days.

dmarcus

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Re: 2015 sea ice area and extent data
« Reply #782 on: July 31, 2015, 08:37:37 PM »
"aren't you 1 day off?"

Is this a leap year issue? If you compare July 31, 2015 to July 31, 2012 you get one result. If you compare day 210 of 2015 to day 210 of 2012 you get a (slightly) different result. Is one better than the other, or are they just different? They each create a potential problem: If you compare dates, then it's hard to compare to February 29. If you compare days of the year, it's hard to compare to Day 366.

plinius

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Re: 2015 sea ice area and extent data
« Reply #783 on: July 31, 2015, 08:52:25 PM »
Could interpolate values onto true date in the solar year, if one wants to go for that. So, our day 210 in 2015 is in truth the day 210.75.

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Re: 2015 sea ice area and extent data
« Reply #784 on: July 31, 2015, 08:57:30 PM »
Or just choose one of the two straightforward methods, with an exclusionary rule: "No comparisons allowed on February 29, or on Day 366!"  ;)

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Re: 2015 sea ice area and extent data
« Reply #785 on: July 31, 2015, 09:21:29 PM »
Wow, amazing. July 2015 saw the first century break average, for the first time since at least 2006 (my spreadsheet doesn't go back further): 101,093 km2 per day on average.

And 2015 now has the most century breaks for the year to date: 44 (2013 is second with 43, and 2012 is third with 42 CBs).
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Re: 2015 sea ice area and extent data
« Reply #786 on: August 01, 2015, 12:52:45 AM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Thu       4.562689
Fri -30.1  4.532572
Sat -119.4  4.413175

Saturday's century is mostly the result of the CAB (-63k4). Smaller contributions from Baffin(-17k), CAA (-15k) and Laptev (-14k).

Some of the concentration drop seems to align with the heating over the north of CAA and the bordering CAB.

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).
I'm surprised that there are significant concentration drops in what is traditionally the most solid ice area next to Greenland. That we have a low compactness isn't a surprise to me at all, given the way the ice is broken up but no strong melt front has been established.

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Re: 2015 sea ice area and extent data
« Reply #787 on: August 01, 2015, 01:26:43 AM »
According to my  figures that  puts SIA at  second lowest;  just  50K km^2 above 2012. and NSIDC compaction (SIA/SIE) at 4.3% below 2012.  (66.2% vs 61.9%).

That  suggests there is plenty of room for further rapid reductions.
Are you sure about that second place? Using Wipneus' numbers, my records show CT SIA as 4th place for Day 0.5835, 371k behind 2012:

2012: 3,915,334 km2
2011: 4,186,187 km2
2007: 4,270,627 km2
2015: 4,285,889 km2

OTOH, 2015 SIA is now a pretty comfortable 512k ahead of 2013, and a remarkable 728k km2 ahead of 2014. (So much for the "rebound").

My take: 2015 almost certainly won't catch 2012; at this point, that would require an further loss of greater thasn 2 million km2. But beating 2007 for second is a very real possibility at this point; to do so, we'd need to see another 1.37 million km2 of loss over the next six weeks or so, an average of roughly 35k per day. (For the record, 2007 lost 1.35 million km2 between now and that year's maximum; 2013 dropped by an additional 1.244 million; 2014 lost another 1.53 million; and 2012 squeezed out another 1.68 million.)

Jim,
You are right. I have your figures listed for the 1st of August  ie day 213 or 0.5835 by Cryosphere's fascinating numbering system.  Wipneus's reference latest  figure is for day 211 which is Thursday 30th.  This could mean that I have aligned the dates for this year against actual dates and in previous years have still got the figures aligned against CT days.  (Checked that and thats what  has happened!! So do I  want the convenience of having the values listed against the same day as their extent  equivalents or do I  leave them misaligned!)
« Last Edit: August 01, 2015, 01:42:46 AM by DavidR »
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OldLeatherneck

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Re: 2015 sea ice area and extent data
« Reply #788 on: August 01, 2015, 02:03:15 PM »
During the last 16 days of July, the ADR-NIPR Sea Ice Extent lost a whopping 1,646,110 KM2, which is the most ever lost in the 2003-2014 time frame. Looking ahead to the first half of August, during the first 15 days the average losses are just over 70K/day. So if we see any century or near-century drops, we can gain ground against 2007 and 2011. For all practical purposes 2012's record will not be matched this year. It was August of that year when 2012 lost just sort of 2.6M KM2. Below are the current SIE chart as well as an updated table of simulated projections thru September 15th.



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Re: 2015 sea ice area and extent data
« Reply #789 on: August 01, 2015, 04:25:23 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):

Sat       4.413029
Sun -127.4  4.285616
Mon -39.7  4.245879

Only the ESS has a substantial contribution for Monday's slow decline: -19k8. The CAA  ice area even increased somewhat (+13k3).

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 #790 on: August 01, 2015, 05:05:09 PM »

NSIDC SIE down around 90k

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Re: 2015 sea ice area and extent data
« Reply #791 on: August 01, 2015, 06:31:09 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):

Sat       4.413029
Sun -127.4  4.285616
Mon -39.7  4.245879

Only the ESS has a substantial contribution for Monday's slow decline: -19k8. The CAA  ice area even increased somewhat (+13k3).

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).

The last holdout for pre-2000 is 1999: 4.2044988. So in the very likely(?) event that Tuesday is over 41.4 k, then 2015 is firmly in 2000' territory (no surprise).
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Subjectivist

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Re: 2015 sea ice area and extent data
« Reply #792 on: August 02, 2015, 05:32:36 AM »
As I understand it the cold fresh melt water is more buoyant than the salt water just beneath it so in calm conditions it floats on top and spread out in a very thin layer until mixing in and effectively dissipating.  However when high winds or stormy weather mixes things up the fresh melt water is quickly mixed into the saltier water just below dissipating it quickly.

Is this an accurate picture of how the mixing process works?

If so does the mixing slow down the formation of first year ice by removing the easily frozen fresh water from the surface layer?

TIA

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Re: 2015 sea ice area and extent data
« Reply #793 on: August 02, 2015, 01:37:09 PM »
Mixing can cause more immediate surface ice melt. If no mixing occurs then the warmer salt water can got moved under the thicker ice causing it to lose its thickness. Now when freezing comes if the water is mixed then the heat from the water is lost to the air those freezing water faster. If on the othr hand you do have a layer of fresh water that will freeze , but the warmer salt water will take much longer to freeze and slow down the freezing process.
Very simplified explanation and probably missing some very important factors, but do believe that is the general idea what does happen.
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Jim Pettit

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Re: 2015 sea ice area and extent data
« Reply #794 on: August 02, 2015, 02:17:41 PM »
ADS-NIPR Extent:
6,468,143 km2 (01 August)
Down 7,473,917 km2 (53.61%) from 2015 maximum of 13,942,060 km2 on 15 February.
3,290,688 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 95,719 km2 (-1.46%) from previous day.
Down 533,649 km2  (-7.62%) over past seven days (daily average: -76,236 km2).
Down 95,719 km2  (-1.46%) for August (daily average: -95,719 km2).
739,268 km2 below 2000s average for this date.
13,990 km2 below 2010s average for this date.
264,241 km2 below 2014 value for this date.
385,743 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
64 days this year (30.05% year-to-date) have recorded the lowest daily extent.
32 days (15.02%) have recorded the second lowest.
32 days (15.02%) have recorded the third lowest.
128 days (60.09%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
4,245,879 km2 (02 August [Day 0.5836])
Down 9,028,676 km2 (68.01%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
2,011,870 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 40,010 km2 (-.93%) from previous day.
Down 512,395 km2 (-10.77%) over past seven days (daily average: -73,199 km2).
Down 167,296 km2 (-3.79%) for August (daily average: -83,648 km2).
819,742 km2 below 2000s average for this date.
133,049 km2 below 2010s average for this date.
624,353 km2 below 2014 value for this date.
458,683 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
7 days this year (3.27% year-to-date) have recorded the lowest daily area.
19 days (8.88%) have recorded the second lowest.
29 days (13.55%) have recorded the third lowest.
55 days in total (25.7%) have been among the lowest three on record.

Wipneus

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Re: 2015 sea ice area and extent data
« Reply #795 on: August 02, 2015, 04:14:30 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):

Sat       4.413029
Sun -127.4  4.285616
Mon -40.1  4.245564
Tue -119.6  4.125955

Yet another century on Tuesday, thanks goes to the contributors CAB (-35k7), Beaufort (-19k), CAA (-18k5), Baffin (-13k), Laptev (-11k) and Hudson (-10k).

It is the first of the month of course and some of the drops will be caused by the August ocean masks. My guess it is not much though.

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 #796 on: August 02, 2015, 05:34:42 PM »
Update for the week to August 1st

The current 5 day mean is on 6,943,200km2 while the 1 day extent is at 6,712,000km2.
The daily anomaly (compared to 81-10) is at -1,321,970km2, an increase from -1,306,980km2 last week. The anomaly compared to the 07, 11 and 12 average is at +365,200km2, a decrease from +438,553km2 last week. We're currently 5th lowest on record, up from 6th last week.



The average daily change over the last 7 days was -87.2k/day, compared to the long term average of -85.1k/day, and the 07, 11 and 12 average of -76.7k/day.
The average long term change over the next week is -74.7k/day, with the 07, 11, and 12 average being -92.6k/day.



The loss so far this August is the 6th largest on record. To achieve the largest monthly drop, a daily loss of at least 89.0k/day is required, while the smallest drop requires a loss of no more than 37.8k/day and an average drop requires a loss of 55.7k/day.



The extent loss this July was the 4th largest on record, while the average extent was the 7th smallest on record.




seaicesailor

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Re: 2015 sea ice area and extent data
« Reply #797 on: August 02, 2015, 07:06:49 PM »
How misleading cold data can be sometimes:



You see this plot and the word "recovery", that is beyond rebound if you ignore statistics, may come to your mind.

And there is general agreement (almost certainty) that July has been one of the worst months for the ice, that the rebound years are gone and past, and that the state of the ice is really really bad


Wipneus

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Re: 2015 sea ice area and extent data
« Reply #798 on: August 03, 2015, 04:11:19 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Mon       4.246491
Tue -119.7  4.126767
Wed +9.6  4.136411

A small increase this Wednesday, "caused" by "lake ice" increasing +14k5. Of the other regions only CAA changed significantly: -17k6.

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 #799 on: August 04, 2015, 04:18:43 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):

Tue       4.126390
Wed +9.6  4.136031
Thu -52.2  4.083793

The semi-century drop on Thursday came with help from lake ice (-12k8). Conventional regions that contributed are CAA (-13k3) and Beaufort (-10k5).

Extent drops are much bigger especially in the Beaufort and the bordering part of the CAB where all these stretches of open water are now being captured by  the (relatively) coarse grid used by NSIDC.
 
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).