2014 sea ice area and extent data

[Jim Pettit]

IJIS Extent:

7,186,066 km2 (25 July)

Down 7,262,350 km2 (50.26%) from 2014 maximum of 14,448,416 km2 on 20 March.

4,008,611 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).

Down 68,159 km2 from previous day.

Down 332,478 km2 over past seven days (daily average: -47,497 km2).

Down 1,871,491 km2 for the month of July (daily average: -71,980 km2).

536,592 km2 below 2000s average for this date.

321,003 km2 above 2010s average for this date.

246,437 km2 above 2013 value for this date.

674,559 km2 above 2012 value for this date.

Fourth lowest July to-date average.

Seventh lowest value for the date.

11 days this year (5.31% year-to-date) have recorded the lowest daily extent.

14 days (6.76%) have recorded the second lowest.

56 days (27.05%) have recorded the third lowest.

81 days (39.13%) in total have been among the three lowest on record.

[Siffy]

Fourth lowest July to-date average.

When you say this do you mean the fourth slowest extent loss for july to date?

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area increase next Tuesday of about +41k.

Again the sea ice area of the CAB is massively increasing (+76k). Declines in Kara (-25k) and by lake "ice (-10k) don't help enough.

By extent Kara has big decline as well (-35k), ESS decline is even larger (-38k). Other regions add enough to make the total a fat century.

Details:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2014-07-26 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  4388.6   -3.3   -31.1    822.3  -37.7   +44.8    121.0  -13.5  -397.7
               Kara Sea             Barents Sea           Greenland Sea
   320.9  -34.5  -186.2     77.5   -4.9   -66.5    254.8  -15.3  -121.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    65.8  -20.3  -222.9      0.0   +0.0    +0.0    178.9   -6.3   -75.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   596.8  -15.0   -43.1    282.3   -7.5   -96.5    267.6   +0.8   -38.9
             Bering Sea          Sea of Okhotsk                   Lakes
     3.6   -2.4    +2.2     23.5   -1.5   +23.5    120.1  -30.4    -2.1
          Other regions       Total (ex. lakes)
    28.0   +5.8   +28.0   7431.5 -155.7 -1181.4

Area (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  3541.9  +75.6  -141.0    539.5   -4.8   +46.7     59.8   -5.2  -254.2
               Kara Sea             Barents Sea           Greenland Sea
   163.1  -24.5  -135.6     28.9   +0.3   -31.5    100.8   -8.6   -76.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    24.9   -4.8   -98.0      0.0   +0.0    +0.0     64.9   -4.6   -43.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   377.4   +6.7   -32.5    147.7  +19.7   -85.8    133.5   +4.9   -38.6
             Bering Sea          Sea of Okhotsk                   Lakes
     1.1   -0.0    +0.7      8.2   -0.1    +8.2     78.1  -10.4   +24.4
          Other regions       Total (ex. lakes)
     6.7   +1.6    +6.7   5198.7  +56.2  -874.9

[Wipneus]

Now with the period in 2013 starting that ice area sharply increased I thought the ice area in the Central Arctic Basin region would finally dip below 2013, it seems that 2014 starts doing the same!

(legend: black NSIDC 2014, green 2013, yellow 2012, red 2007)
 

[Jim Pettit]

Fourth lowest July to-date average.

When you say this do you mean the fourth slowest extent loss for july to date?

Fourth lowest, not slowest. And by that I mean that of the periods from 01 July through 26 July (inclusive) in the JAXA extent record, that period in 2014 has seen the fourth lowest average. Here are the actual top(bottom?) ten numbers by rank:

2011: 7,648,024
2012: 7,729,847
2007: 7,916,093
2014: 7,952,416
2013: 8,011,391
2010: 8,045,588
2006: 8,279,650
2009: 8,500,952
2005: 8,595,499
2008: 8,637,274

[crandles]

CT area with Wipneus' updates:
5.261 - 0.149 + 0.011 + 0.041 = 5.164

which then compares with
2012.5698  -1.7668682   4.2991047
2011.5698  -1.6336946   4.4889936
2007.5698  -1.6328344   4.4898539
2010.5698  -1.4181185   4.7045698
2013.5698  -1.2506790   4.8720093
2008.5698  -0.9059530   5.1600199
2014
2005.5698  -0.9052811   5.217407
2009.5698  -0.8969593   5.225729
2006.5698  -0.8484545   5.2742338

Down to 7th lowest for day (from 6th lowest).
Up to 865k above 2012.

Losses from day .5698 to minimum and where we end if losses from now on are the same
2005   1.126   4.038
2006   1.244   3.92
2007   1.57   3.594
2008   2.156   3.008
2009   1.801   3.363
2010   1.632   3.532
2011   1.584   3.58
2012   2.065   3.099
2013   1.318   3.846
      
07+Average   1.732   3.432 (7th lowest)
07+Average+3sd   2.620   2.544 (2nd lowest)
07+Average+2sd   2.324   2.84 (2nd lowest)
07+Average+sd   2.028   3.136 (6th lowest)
07+Average-sd   1.436   3.728 (8th lowest)
07+Average-2sd   1.141   4.023 (8th lowest)

Further CT losses of 1.1 to 2.2 is still quite a range. Typical reductions like years 2007 onwards leads to 6th to 8th lowest area. Dropping to become lowest on record is about a 4sd event and therefore seems exceedingly unlikely.

[Frivolousz21]

Don't worry 2014 will be recommence the cliff diving shortly.

[BornFromTheVoid]

Update for the week to July 26th

The current 5 day mean is on 7,606,530km2 while the 1 day extent is at 7,431,630km2.

The daily anomaly (compared to 81-10) is at -1,168,450km2, a decrease from -1,392,040km2 last week. The anomaly compared to the 07, 11 and 12 average is at +577,770km2, a change from +416,680km2. We're currently 7th lowest on record, down from 5th last week.
The average daily change over the last 7 days was -56.3k/day, compared to the long term average of -88.3k/day, and the 07, 11 and 12 average of -79.3k/day.

The average long term change over the next week is -86.1k/day, with the 07, 11, and 12 average being -73.8k/day.

The loss so far this July is the 16th largest on record. To achieve an average July loss, a drop of 81.2k/day is required, with the largest loss requiring -250.4k/day and the smallest requiring an increase of 50.1k/day.

[jdallen]

From area calculated from NSIDC sea ice concentration I expect a CT-area increase next Tuesday of about +41k.

Again the sea ice area of the CAB is massively increasing (+76k). Declines in Kara (-25k) and by lake "ice (-10k) don't help enough.

By extent Kara has big decline as well (-35k), ESS decline is even larger (-38k). Other regions add enough to make the total a fat century.

I am scratching my head trying to figure out how, under current conditions, the CAB can be increasing so dramatically, and other regions not dropping, that we can have a net increase in area.

It makes utterly no sense.  Look at these temperatures.  There just isn't any heat sink available to pick up all the energy which would be released by the freeze.  There is *still* almost insolation, running close to 400W/M2 minimum.

No sense what so ever.

http://weather.gc.ca/data/analysis/351_50.gif

[Wipneus]

No sense what so ever.

jd, remember the CAB had a huge decline (-126k, just two days ago) so, if you choose so, consider this as a statistical fluke followed by a return to normal.

On the other hand I like to consider more physical reasons (rather than comment on instrumental noise).
It goes like this:
These data are produced using the so called NASA Team algorithm. The data compared with other algorithms (Jaxa: Bootstrap, Uni Hamburg: ASI) is very sensitive to the surface conditions. So ice getting wet due to melting (temp goes above 0^oC) and later freezing again ( temp goes below 0^oC) over a sufficient large area is sufficient explanation: just a temp change of 0^oC will do. Same argument goes with rain fall, or perhaps even snow.

[Jim Pettit]

IJIS Extent:

7,097,907 km2 (27 July)

Down 7,350,509 km2 (50.87%) from 2014 maximum of 14,448,416 km2 on 20 March.

3,920,452 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).

Down 88,159 km2 from previous day.

Down 391,809 km2 over past seven days (daily average: -55,973 km2).

Down 1,959,650 km2 for the month of July (daily average: -72,580 km2).

539,434 km2 below 2000s average for this date.

325,094 km2 above 2010s average for this date.

215,295 km2 above 2013 value for this date.

731,789 km2 above 2012 value for this date.

Fourth lowest July to-date average.

Seventh lowest value for the date.

11 days this year (5.29% year-to-date) have recorded the lowest daily extent.

14 days (6.73%) have recorded the second lowest.

56 days (26.92%) have recorded the third lowest.

81 days (38.94%) in total have been among the three lowest on record.

CT Area:

5,096,162 km2 (27 July [Day 0.5671])

Down 8,391,175 km2 (62.22%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].

2,862,152 km2 above record minimum area of 2,234,010 km2 (14 September 2012).

Down 7,323 km2 from previous day.

Down 438,782 km2 over past seven days (daily average: -62,683 km2).

Down 2,443,317 km2 for the month of July (daily average: -90,493 km2).

338,795 km2 below 2000s average for this date.

375,427 km2 above 2010s average for this date.

269,045 km2 above 2013 value for this date.

728,130 km2 above 2012 value for this date.

Seventh lowest July to-date average.

Sixth lowest value for the date.

12 days this year (5.77% year-to-date) have recorded the lowest daily area.

21 days (10.1%) have recorded the second lowest.

17 days (8.17%) have recorded the third lowest.

50 days in total (24.04%) have been among the lowest three on record.

Lower than 1979, 1980, 1982, 1983, 1986, 1987, 1988, and 1996 minimums

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area increase next Wednesday of about +38k.

It is again the CAB that is causing the "recovery": +36k. Lastev has the biggest decline (-16k).

By extent it is also Laptev that leads, now with a very big -42k it widens the Laptev Bite.

The details:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2014-07-27 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  4378.8   -9.8   -38.4    807.8  -14.5   +42.7     79.3  -41.7  -428.9
               Kara Sea             Barents Sea           Greenland Sea
   331.0  +10.1  -166.8     76.1   -1.4   -62.1    261.3   +6.5  -107.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    71.7   +5.9  -204.1      0.0   +0.0    +0.0    169.2   -9.7   -74.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   608.6  +11.8   -25.9    288.0   +5.7   -87.4    269.9   +2.3   -30.2
             Bering Sea          Sea of Okhotsk                   Lakes
     1.2   -2.4    -0.1     23.4   -0.1   +23.4    142.4  +22.3   +20.6
          Other regions       Total (ex. lakes)
    26.8   -1.1   +26.8   7393.0  -38.5 -1133.5

Area (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  3578.4  +36.4   -99.0    541.5   +2.0   +58.2     43.8  -16.0  -261.5
               Kara Sea             Barents Sea           Greenland Sea
   158.2   -4.9  -132.9     27.9   -1.0   -29.7    103.8   +3.0   -69.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    25.7   +0.9   -90.8      0.0   +0.0    +0.0     63.2   -1.8   -39.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   390.7  +13.4   -12.5    140.4   -7.4   -90.0    139.8   +6.3   -27.1
             Bering Sea          Sea of Okhotsk                   Lakes
     0.3   -0.9    -0.2      8.3   +0.0    +8.3     86.4   +8.3   +32.8
          Other regions       Total (ex. lakes)
     6.1   -0.7    +6.1   5228.0  +29.3  -780.9

[Wipneus]

The delta image shows the extent decline in Laptev.

[crandles]

CT area with Wipneus' updates:
5.096 + 0.041 + 0.038 = 5.175

which then compares with
2012.5726  -1.7719828   4.2368927
2007.5726  -1.6576205   4.4083524
2011.5726  -1.6460997   4.4198732
2010.5726  -1.4632245   4.602748
2013.5726  -1.2035657   4.8624072
2008.5726  -0.8923165   5.1165590
2014
2005.5726  -0.8597575   5.2062154
2009.5726  -0.9036895   5.1622834
2006.5726  -0.8347760   5.231196


Remains 7th lowest for day.
Up to 938k above 2012.

Losses from day .5726 to minimum and where we end if losses from now on are the same
2005   1.114   4.061
2006   1.201   3.974
2007   1.5   3.675
2008   2.113   3.062
2009   1.738   3.437
2010   1.531   3.644
2011   1.515   3.66
2012   2.003   3.172
2013   1.308   3.867
      
07+Average   1.673   3.502 (7th lowest)
07+Average+3sd   2.551   2.624 (2nd lowest)
07+Average+2sd   2.259   2.916 (3rd lowest)
07+Average+sd   1.966   3.209 (6th lowest)
07+Average-sd   1.38   3.795 (8th lowest)
07+Average-2sd   1.087   4.088 (9th lowest)

Further CT losses of 1.1 to 2.1 is still quite a range. Typical reductions like years 2007 onwards leads to 6th to 8th lowest area. Dropping to become lowest on record is more than a 4sd event and therefore seems exceedingly unlikely.

[Wipneus]

Plot of area, calculated from NSIDC sea ice concentration data. Basically CT-area but without lake ice and two day earlier.

For five days SIA has hardly changed. If the decline restarts then it is not unusual, if not, a repeat of 2013.

[Jim Hunt]

Hasn't CT day 0.5643 gone missing? 5,260,618  =>   5,103,485

[Jim Pettit]

Hasn't CT day 0.5643 gone missing? 5,260,618  =>   5,103,485

The 0.5643 update was very late in arriving--in fact, I didn't see it until this morning--so I skipped posting it and went directly to 0.5671. However, for those keeping score at home  :

CT Area:

5,103,485 km2 (26 July [Day 0.5643])

Down 8,383,852 km2 (62.16%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].

2,869,476 km2 above record minimum area of 2,234,010 km2 (14 September 2012).

Down 157,133 km2 from previous day.

Down 502,751 km2 over past seven days (daily average: -71,822 km2).

Down 2,435,993 km2 for the month of July (daily average: -93,692 km2).

392,744 km2 below 2000s average for this date.

377,161 km2 above 2010s average for this date.

307,750 km2 above 2013 value for this date.

762,113 km2 above 2012 value for this date.

Seventh lowest July to-date average.

Sixth lowest value for the date.

12 days this year (5.8% year-to-date) have recorded the lowest daily area.

21 days (10.14%) have recorded the second lowest.

17 days (8.21%) have recorded the third lowest.

50 days in total (24.15%) have been among the lowest three on record.

[Jim Hunt]

However, for those keeping score at home  :

Actually I'm keeping score with "Steve Goddard" on Twitter and at the erroneously named "Real Science" blog. My "prediction" came true

https://twitter.com/jim_hunt/statuses/493484244992544768

[Jim Pettit]

IJIS Extent:

7,003,772 km2 (28 July)

Down 7,444,644 km2 (51.53%) from 2014 maximum of 14,448,416 km2 on 20 March.

3,826,317 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).

Down 94,135 km2 from previous day.

Down 435,392 km2 over past seven days (daily average: -62,199 km2).

Down 2,053,785 km2 for the month of July (daily average: -73,349 km2).

549,814 km2 below 2000s average for this date.

308,089 km2 above 2010s average for this date.

226,320 km2 above 2013 value for this date.

711,001 km2 above 2012 value for this date.

Fourth lowest July to-date average.

Seventh lowest value for the date.

11 days this year (5.26% year-to-date) have recorded the lowest daily extent.

14 days (6.7%) have recorded the second lowest.

56 days (26.79%) have recorded the third lowest.

81 days (38.76%) in total have been among the three lowest on record.

CT Area:

5,132,793 km2 (28 July [Day 0.5698])

Down 8,354,545 km2 (61.94%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].

2,898,783 km2 above record minimum area of 2,234,010 km2 (14 September 2012).

Up 36,631 km2 from previous day.

Down 317,200 km2 over past seven days (daily average: -45,314 km2).

Down 2,406,686 km2 for the month of July (daily average: -85,953 km2).

272,081 km2 below 2000s average for this date.

433,299 km2 above 2010s average for this date.

260,783 km2 above 2013 value for this date.

833,688 km2 above 2012 value for this date.

Seventh lowest July to-date average.

Sixth lowest value for the date.

12 days this year (5.74% year-to-date) have recorded the lowest daily area.

21 days (10.05%) have recorded the second lowest.

17 days (8.13%) have recorded the third lowest.

50 days in total (23.92%) have been among the lowest three on record.

[Jim Pettit]

Actually I'm keeping score with "Steve Goddard" on Twitter and at the erroneously named "Real Science" blog. My "prediction" came true

https://twitter.com/jim_hunt/statuses/493484244992544768

Excellent! In the past things I've written have been the featured subject/target of "Goddard's" inane blog, so I know the feeling. 

[Jim Hunt]

Excellent! In the past things I've written have been the featured subject/target of "Goddard's" inane blog, so I know the feeling. 

Excellent (if you see what I mean)! I've taken the liberty of mentioning your name in my latest critique of the denialistas mathematical capabilities:

http://forum.arctic-sea-ice.net/index.php/topic,578.msg32720.html#msg32720

[Jim Pettit]

I find it odd/flukish that CT SIA chose to screech to a halt on the same day it did last year--0.5616--and to experience similar results after that. It'll be very interesting to watch over the next week or so to see whether 2014 enters August at a dead stop as did 2013. Over the next six days in 2013, area increased by 6k. By comparison, the same period in 2012 saw a drop of 640k.

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area increase next Thursday of about +11k.

The uptick when realized can be said to be caused by lake "ice": +16k. Otherwise there is a big drop of -28k in the CAA and ( another) uptick in the CAB.

By extent it is the ESS with a very big -44k drop, followed at a distance by Beaufort and Chukchi (-21k each). Kara has a +19k uptick.

All the details:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2014-07-28 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  4369.6   -9.2   -44.9    763.6  -44.2   +11.7     89.1   +9.8  -408.6
               Kara Sea             Barents Sea           Greenland Sea
   350.1  +19.1  -139.0     74.3   -1.8   -57.9    268.1   +6.8   -94.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    63.9   -7.7  -199.2      0.0   +0.0    +0.0    161.1   -8.1   -72.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   596.8  -11.8   -32.0    267.2  -20.8  -104.5    248.7  -21.2   -44.6
             Bering Sea          Sea of Okhotsk                   Lakes
     2.4   +1.2    +1.2     21.8   -1.6   +21.8    190.1  +47.7   +68.8
          Other regions       Total (ex. lakes)
    27.9   +1.0   +27.9   7304.5  -88.5 -1135.6

Area (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  3594.9  +16.5   -77.2    536.0   -5.5   +62.4     43.9   +0.0  -252.9
               Kara Sea             Barents Sea           Greenland Sea
   170.6  +12.5  -113.1     28.2   +0.2   -26.7    107.2   +3.4   -62.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    23.3   -2.5   -87.2      0.0   +0.0    +0.0     60.0   -3.2   -37.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   362.7  -28.0   -34.0    143.5   +3.2   -83.5    135.5   -4.3   -26.3
             Bering Sea          Sea of Okhotsk                   Lakes
     0.5   +0.2    +0.1      8.0   -0.2    +8.0    102.1  +15.7   +48.6
          Other regions       Total (ex. lakes)
     6.2   +0.2    +6.2   5220.6   -7.4  -725.1

[crandles]

CT area with Wipneus' updates:
5.133 + 0.038 +0.011 = 5.182

which then compares with
2012.5753  -1.7226093   4.2358670
2011.5753  -1.7050449   4.3038306
2007.5753  -1.6614076   4.347467
2010.5753  -1.5289704   4.4799051
2013.5753  -1.1519138   4.8569617
2008.5753  -1.0137799   4.9446964
2009.5753  -1.0406138   4.9682617
2006.5753  -0.8360760   5.172799
2014
2005.5753  -0.7686426   5.240232

Down to 9th lowest for day (from 7th).
Up to 946k above 2012.

Losses from day .5726 to minimum and where we end if losses from now on are the same
2005   1.148   4.034
2006   1.143   4.039
2007   1.428   3.754
2008   1.344   3.838
2009   1.520   3.662
2010   1.896   3.286
2011   1.575   3.607
2012   2.002   3.180
2013   1.303   3.879
      
07+Average   1.581   3.601 (8th lowest)
07+Average+3sd   2.391   2.791 (2nd lowest)
07+Average+2sd   2.121   3.061 (5th lowest)
07+Average+sd   1.851   3.331 (6th lowest)
07+Average-sd   1.311   3.871 (8th lowest)
07+Average-2sd   1.041   4.141 (10th lowest)
      
Further CT losses of 1.1 to 2.1 is still quite a range. Typical reductions like years 2007 onwards leads to 6th to 8th lowest area. Dropping to become lowest on record is more than a 4sd event and therefore seems exceedingly unlikely.

Edit error corrections

[jdallen]

I would really love to understand how extent can drop 94k, and area can increase 36k on the same day, while half the basin is being blasted by some of the best melting conditions since June.

I understand the mechanics of how it might happen, but it does not seem to me that there is a lot of compaction going on, nor does it seem there are regionally cold enough temperatures to create ice when so much energy is going *into* it.

I mean, look at the temperatures?

http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php

http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-temperature/

It just does not seem to me that it is cold enough across areas with enough open water to explain the freezing of an area which logically (to offset melting which demonstrably is happening in some areas) would need to be the size of the state of Washington.

[jdallen]

I feel a need to expand a bit further.

Extent is a pretty straight forward measurement - it's moderately easy to gauge, and in some ways is less prone to complications in measurement like cloud and changes in concentration.

Lots of things mess with area. So much so that with recent numbers I'm questioning the utility of measuring area on short time frames during melt season.  At this juncture of the season it seems to me the sensing systems used suffer significant challenges in skillfully determine changes up, *or* down.  That makes me wonder about our understanding of volume, and our assessments of the quality of the ice. 

I'm worried we are missing something important hidden in whatever mechanism(s) jerk(s) around the measurements.

[John_The_Elder]

The most probable answer to why area has increased is that with all the melt, the ice can no longer contain the large melt ponds  and they have drained. The bottom of the melt ponds are recognized as ice and area goes up. The ice (at the bottom of the pond) is probably not in good condition and may be prone to melting out in the near future. Then area will go back down.....
John

[sofouuk]

extent is traditionally the main metric because area is difficult to measure accurately. such limitations are why crude measurements like monthly averages are still widely used. there's no mystery here - the detail is often inaccurate but if there's no systematic bias the big picture will be reasonable approximation. what is that unsatisfying?

[seattlerocks]

A few days ago, the region above Fram was hit with warm wind and reversed flow of warm water. Concentration was reduced by a lot, but probably not so much extent reduction. Back to normal, refreezing-- and even in a few days there may be normal Fram export --. Can this be one cause of the uptick?

[ktonine]

John_The_Elder and sofouuk have given the probable answers.  We are dealing with large uncertainties in both measurements.  Area uncertainties can be double-digit percent at times.  Extent may reach as high as 7%.

Day-to-day changes are simply not that important.  There is a reason why multi-day averages are the norm and monthly averages used by most scientists.

It's hard to watch daily numbers and not get excited or perplexed, but there are times you just have to ignore them ... and wait.

[jdallen]

The most probable answer to why area has increased is that with all the melt, the ice can no longer contain the large melt ponds  and they have drained. The bottom of the melt ponds are recognized as ice and area goes up. The ice (at the bottom of the pond) is probably not in good condition and may be prone to melting out in the near future. Then area will go back down.....
John

I'm familiar with the ice pond hypothesis, and have become increasingly skeptical of it generally.  I've read all sorts of anecdotal discussion; I haven't seen anything written up about it.

In the case of the last few days, I'm also skeptical because of the scale of ponding that would have to drain to cause the 200K KM2 swing.  It implies consistent behavior in a chaotic system; if conditions are conducive to drain ponds, they are also conducive to *creating* them at near or better the rate.

I'm also skeptical of any sort of refreeze.  It would require similarly consistent conditions changing over areas which have meltponding; where the weather *has* been below zero in the last 24 hours *hasn't* tended to be where we have ponds.  Further, the general level of heat blowing its way into the arctic is is completely crosswise to large areas cooling off.

The quality of the ice has me suspicious as well.consider below.  It isn't from the central basin - I can't find cloud free areas to follow.  However, it illustrates how in an area, where there is active melting, conditions can produce the illusion of increasing area (Chukchi).  It seems to me it shows very weak ice disintegrating and expanding over a larger surface:






So, In short, I'm not convinced its melt ponds.  I'm also not convinced the increasing ice area implies the ice is more robust.  I'm also not yet convinced its *worse*, but am concerned that what's going on calls into question some of the metrics we are deriving from area.

[Wipneus]

I would really love to understand how extent can drop 94k, and area can increase 36k on the same day, while half the basin is being blasted by some of the best melting conditions since June.

Please supply evidence your claim that half of the basin is "blasted". I see nothing that bad. The links you supply show temperatures below and around 0^oC over most of the basin. The simple mean http://ocean.dmi.dk/arctic/meant80n.uk.php shows lower than normal and a break to even lower temperatures at the same time as the increases in NSIDC area.

Where is the "blasting" in half of the basin in attached NOAA temp anomaly image?

I understand the mechanics of how it might happen, but it does not seem to me that there is a lot of compaction going on, nor does it seem there are regionally cold enough temperatures to create ice when so much energy is going *into* it.

...

It just does not seem to me that it is cold enough across areas with enough open water to explain the freezing of an area which logically (to offset melting which demonstrably is happening in some areas) would need to be the size of the state of Washington.

Maybe you have *not* understood the issue. Once you understand that *this* particular ice index can seriously underestimate area under melting conditions, it is *not* necessary to have *any* open water for area to jump up, if it is just a return to normal. As an example, whet ice turning to ice with a dry surface can do the explanation, with temperatures around zero that is exactly what you expect.

This is also the reason why I compare with other sea ice area indexes, Jaxa's and Uni Hamburg's sea ice concentration are far less sensitive to the surface conditions and these don't show this extreme area increase (https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png).

[Wipneus]

The most probable answer to why area has increased is that with all the melt, the ice can no longer contain the large melt ponds  and they have drained. The bottom of the melt ponds are recognized as ice and area goes up. The ice (at the bottom of the pond) is probably not in good condition and may be prone to melting out in the near future. Then area will go back down.....
John

John, all sea ice concentration products that I know of react the same way on melt ponds: they see water and treat it as such.
The NSIDC sea ice concentration (and consequently CT area) shows an uptick where eg. Jaxa and Uni Hamburg do not, that needs an other explanation than melt ponds.

[Jim Pettit]

IJIS Extent:

6,893,488 km2 (29 July)

Down 7,554,928 km2 (52.29%) from 2014 maximum of 14,448,416 km2 on 20 March.

3,716,033 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).

Down 110,284 km2 from previous day.

Down 466,876 km2 over past seven days (daily average: -66,697 km2).

Down 2,164,069 km2 for the month of July (daily average: -74,623 km2).

577,421 km2 below 2000s average for this date.

264,076 km2 above 2010s average for this date.

164,261 km2 above 2013 value for this date.

690,455 km2 above 2012 value for this date.

Fourth lowest July to-date average.

Fifth lowest value for the date.

11 days this year (5.24% year-to-date) have recorded the lowest daily extent.

14 days (6.67%) have recorded the second lowest.

56 days (26.67%) have recorded the third lowest.

81 days (38.57%) in total have been among the three lowest on record.

CT Area:

5,173,348 km2 (29 July [Day 0.5726])

Down 8,313,989 km2 (61.64%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].

2,939,339 km2 above record minimum area of 2,234,010 km2 (14 September 2012).

Up 40,556 km2 from previous day.

Down 167,748 km2 over past seven days (daily average: -23,964 km2).

Down 2,366,130 km2 for the month of July (daily average: -81,591 km2).

191,796 km2 below 2000s average for this date.

514,294 km2 above 2010s average for this date.

310,941 km2 above 2013 value for this date.

936,456 km2 above 2012 value for this date.

Seventh lowest July to-date average.

Eighth lowest value for the date.

12 days this year (5.71% year-to-date) have recorded the lowest daily area.

21 days (10.%) have recorded the second lowest.

17 days (8.1%) have recorded the third lowest.

50 days in total (23.81%) have been among the lowest three on record.

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area decline next Friday of about -43k.

Another big increase in the CAB (+64k) is offset by a giant (because its small size) area decline in the ESS (-62k) are the main ingredients, it is spiced up by a +29k uptick in the CAA and smaller declines in most other regions.

In extent the ESS also scored mega big (-83k), joined by Greenland Sea and Hudson (-30k each) but offset by uptick in Barents and the CAA.

All the details:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2014-07-29 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  4362.4   -7.2   -49.6    680.7  -82.8   -58.7     72.2  -16.9  -415.3
               Kara Sea             Barents Sea           Greenland Sea
   349.2   -0.8  -130.9     88.1  +13.8   -38.2    238.5  -29.6  -118.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    57.8   -6.1  -192.7      0.0   +0.0    +0.0    131.8  -29.3   -92.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   620.3  +23.5    -2.8    270.4   +3.2   -97.8    245.5   -3.2   -40.8
             Bering Sea          Sea of Okhotsk                   Lakes
     3.6   +1.2    +2.5     23.9   +2.1   +23.9    167.7  -22.5   +46.2
          Other regions       Total (ex. lakes)
    22.8   -5.0   +22.8   7167.3 -137.2 -1188.0

Area (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  3658.8  +63.8    -8.4    474.1  -61.9    +9.7     32.3  -11.6  -256.8
               Kara Sea             Barents Sea           Greenland Sea
   156.0  -14.6  -120.7     32.7   +4.6   -19.4    101.1   -6.2   -65.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    21.6   -1.6   -83.0      0.0   +0.0    +0.0     46.0  -14.0   -47.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   391.5  +28.8    +1.2    136.2   -7.4   -87.6    128.1   -7.4   -28.5
             Bering Sea          Sea of Okhotsk                   Lakes
     0.7   +0.2    +0.3      8.1   +0.1    +8.1     93.7   -8.3   +40.3
          Other regions       Total (ex. lakes)
     5.2   -1.0    +5.2   5192.3  -28.4  -692.5

[Wipneus]

Here is a delta image showing where those number come from.

[crandles]

CT area with Wipneus' updates:
5.173 + 0.011 - 0.043 = 5.141

which then compares with
2012.5781  -1.8080810   4.0850444
2007.5781  -1.7100575   4.2484188
2011.5781  -1.6878045   4.2706718
2010.5781  -1.5438268   4.4146495
2008.5781  -1.1025327   4.7905927
2013.5781  -1.1418674   4.8166089
2009.5781  -1.0773251   4.8811512
2006.5781  -0.8919851   5.0664911
2014
2005.5781  -0.7752234   5.1832528


Remains 9th lowest for day.
Up to 1056k above 2012.

Losses from day .5781 to minimum and where we end if losses from now on are the same
2005   1.091   4.050
2006   1.037   4.104
2007   1.329   3.812
2008   1.787   3.354
2009   1.457   3.684
2010   1.343   3.798
2011   1.366   3.775
2012   1.851   3.290
2013   1.262   3.879
      
07+Average   1.485   3.656 (8th lowest)
07+Average+3sd   2.193   2.948 (4th lowest)
07+Average+2sd   1.957   3.184 (6th lowest)
07+Average+sd   1.721   3.420 (6th lowest)
07+Average-sd   1.249   3.892 (8th lowest)
07+Average-2sd   1.013   4.128  (10th lowest)

   
Further CT losses of 1.0 to 1.9 is still quite a range. Typical reductions like years 2007 onwards leads to 6th to 8th lowest area. Dropping to become lowest on record is just about a 6sd event and therefore seems exceedingly unlikely.

[jdallen]

I believe I have arrived; I've just been lamb-basted by someone on the the forums I respect.

 

Serves me right for getting carried away by Friv's excitement.

Ok, "Blasted" probably is an overstatement, but it does stand that current weather was considered by many on the forums to be especially conducive for melt, and that it was going to affect most of the Pacific side of the basin; that was the source of my assertion.  I'm fine being proven wrong with it.

To be clear, my concern isn't over just rising area numbers, but over *dropping* numbers as well.  Insecurity with increases in area does absolutely imply similar problems with decreases as well.  I dislike the situation exactly because it makes us less skillful, not that it shows the ice going in the "wrong" direction.

It is also clear that yes, I do not understand what is happening.  I just haven't yet felt the explanations I've seen fully explain what seems to be excess volatility in the measurements.

I value the effort you put into the numbers you post greatly, Wipneus.  Please don't take my posts as any sort of criticism of that effort.

I would really love to understand ...

Please supply evidence your claim that half of the basin is "blasted".
...
Maybe you have *not* understood the issue.
...
This is also the reason why I compare with other sea ice area indexes,
...

[Jim Pettit]

IJIS Extent:

6,811,403 km2 (30 July)

Down 7,637,013 km2 (52.86%) from 2014 maximum of 14,448,416 km2 on 20 March.

3,633,948 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).

Down 82,085 km2 from previous day.

Down 520,531 km2 over past seven days (daily average: -74,362 km2).

Down 2,246,154 km2 for the month of July (daily average: -74,872 km2).

547,177 km2 below 2000s average for this date.

232,067 km2 above 2010s average for this date.

78,074 km2 above 2013 value for this date.

679,214 km2 above 2012 value for this date.

Fourth lowest July to-date average.

Fifth lowest value for the date.

11 days this year (5.21% year-to-date) have recorded the lowest daily extent.

14 days (6.64%) have recorded the second lowest.

56 days (26.54%) have recorded the third lowest.

81 days (38.39%) in total have been among the three lowest on record.

CT Area:

5,188,184 km2 (30 July [Day 0.5753])

Down 8,299,153 km2 (61.53%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].

2,954,174 km2 above record minimum area of 2,234,010 km2 (14 September 2012).

Up 14,835 km2 from previous day.

Down 103,566 km2 over past seven days (daily average: -14,795 km2).

Down 2,351,295 km2 for the month of July (daily average: -78,376 km2).

98,781 km2 below 2000s average for this date.

575,234 km2 above 2010s average for this date.

331,222 km2 above 2013 value for this date.

952,317 km2 above 2012 value for this date.

Seventh lowest July to-date average.

Ninth lowest value for the date.

12 days this year (5.69% year-to-date) have recorded the lowest daily area.

21 days (9.95%) have recorded the second lowest.

17 days (8.06%) have recorded the third lowest.

50 days in total (23.7%) have been among the lowest three on record.

[Siffy]

I am so confused at the increases in CT area over the last four days.

 

[Jim Pettit]

I am so confused at the increases in CT area over the last four days.

 

What seems oddly coincidental is that this year's late-July paused started on precisely the same day--0.5616--on which last year's similar pause got underway. Area has now increased four of the past six days, for a six-day total of decrease of just 39k.

Over the next four days in 2012, SIA dropped by 576k. In fact, 2012 SIA dropped almost exactly 2 million km2 after this date. I'm going to go out on a limb here and predict that neither of those disappearing acts are going to be repeated this year...

[greatdying2]

I am so confused at the increases in CT area over the last four days.

 

Although it may have more to do with instrument limitations (cloud, melt pond vs. ocean water, etc.), I also think of this: Take a shot of tequila, juice of lime, sugar, water, and either (a) a cube of ice or (b) a cube of ice pureed in a blender. Which has more area (and extent), (a) on the rocks or (b) slushy? And which will melt first and no longer be delicious?

[Buddy]

Take a shot of tequila, juice of lime, sugar, water, and either (a) a cube of ice or (b) a cube of ice pureed in a blender. Which has more area (and extent), (a) on the rocks or (b) slushy? And which will melt first and no longer be delicious?

OK.....I'm on thee fourth round of the experiment.....and now I have forgotten what the experiment was about....

[greatdying2]

OK.....I'm on thee fourth round of the experiment.....and now I have forgotten what the experiment was about....

Cheeeeeers!   

[rwmsrobertw]

Take a shot of tequila, juice of lime, sugar, water, and either (a) a cube of ice or (b) a cube of ice pureed in a blender. Which has more area (and extent), (a) on the rocks or (b) slushy? And which will melt first and no longer be delicious?

OK.....I'm on thee fourth round of the experiment.....and now I have forgotten what the experiment was about....

You'd better be careful there, Buddy. Let this be a warning to you: http://www.smbc-comics.com/?id=3366 .

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area decline next FriSaturday of about -140k.

That is in part because the CAB decided to make a u-turn (-60k), partly because the ESS has dropped -52k. CAA is third at some distance (-23k).

Same picture in extent, with less extreme drops, and a big contribution in Kara (-30k). Honorable mention goes to Chukchi for a -21k contribution.

All the details:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2014-07-30 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  4330.9  -31.5   -78.6    658.3  -22.4   -69.3     59.2  -13.0  -418.8
               Kara Sea             Barents Sea           Greenland Sea
   319.5  -29.7  -151.5     79.9   -8.2   -40.2    246.5   +8.0  -104.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    60.4   +2.6  -177.3      0.0   +0.0    +0.0    145.7  +13.9   -68.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   594.8  -25.4   -22.2    265.9   -4.4   -98.8    224.6  -21.0   -54.3
             Bering Sea          Sea of Okhotsk                   Lakes
     3.0   -0.6    +2.0     25.0   +1.0   +25.0    179.4  +11.7   +57.3
          Other regions       Total (ex. lakes)
    20.6   -2.2   +20.6   7034.2 -133.1 -1236.4

Area (value, one day change, anomaly):
           Arctic Basin       East Siberian Sea              Laptev Sea
  3599.2  -59.6   -63.2    422.4  -51.7   -33.4     27.9   -4.4  -254.4
               Kara Sea             Barents Sea           Greenland Sea
   148.5   -7.5  -121.3     35.5   +2.8   -13.8    102.8   +1.7   -61.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
    23.7   +2.0   -74.9      0.0   +0.0    +0.0     50.7   +4.8   -37.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   368.9  -22.5   -14.9    134.3   -1.9   -86.3    113.1  -14.9   -38.2
             Bering Sea          Sea of Okhotsk                   Lakes
     0.6   -0.2    +0.2      7.8   -0.3    +7.8     98.7   +4.9   +45.0
          Other regions       Total (ex. lakes)
     4.5   -0.8    +4.5   5039.8 -152.5  -786.4

[Neven]

From area calculated from NSIDC sea ice concentration I expect a CT-area decline next Friday of about -140k.

As they say in Dutch: hè, hè (=finally).

[deep octopus]

NSIDC one-day extent down to 7,034,360 km², now virtually tied with 2013, slightly above 2009 and 2010, and further above 2007, 2011, and 2012. Still below 2008.

If the trends continue (and forecasts indicate they will for now), 2014 will fall below 2009 and 2013 within the next day or two, as 2009 and 2013 both hit slow patches here.

For long range perspective, 2014 is now below the final minima of 1980, 1982, 1983, 1986, 1988, 1992, and 1996.

[Wipneus]

From area calculated from NSIDC sea ice concentration I expect a CT-area decline next Friday of about -140k.

As they say in Dutch: hè, hè (=finally).

Some may consider it is a coincidence, but the large areas of below 0^oC T2 temperatures have mostly disappeared.

[Jim Hunt]

From area calculated from NSIDC sea ice concentration I expect a CT-area decline next Friday of about -140k.

Should that be Saturday? You've already called Friday!