2018 sea ice area and extent data

[Wipneus]

Here are the area numbers.

NSIDC:
NH Area
1 2012-09-12 2.228429
2 2016-09-07 2.400654
3 2011-09-05 2.916451
4 2017-09-11 2.939311
5 2007-09-07 2.952352
6 2010-09-07 3.071674
7 2008-09-08 3.079552
8 2015-09-07 3.139137
9 2018-09-09 3.156973
10 2009-09-08 3.547109


Uni Hamburg:
1 2012-09-07 2.691880
2 2016-09-08 3.025680
3 2015-09-08 3.515583
4 2017-09-01 3.670791
5 2018-09-08 3.752504
6 2014-09-14 4.127480
7 2013-09-09 4.266727


Uni Bremen:
1 2016-09-08 3.037657
2 2017-09-01 3.673478
3 2018-09-08 3.758840
4 2012-07-31 4.795841
5 2014-10-20 6.832352
6 2015-07-01 8.158377
7 2013-11-23 9.611285

[lurkalot]

Thank you so much, Wipneus,  what would we do without you? These tables certainly cast doubt on JAXA showing 2018 extent above 2017.

But you also remind us that comparisons with all but the most recent years are somewhat suspect and so Bremen and JAXA charts should carry a 'health warning' (but don't).

[colchonero]

I don't see any doubt really. JAXA extent has it above 2017, about the same km2 amount, as NSIDC has 2018 area above the 2017.

Uni Hamburg area has it also above 2017.

Uni Bremen chart doesn't make any sense since it shows the 7th lowest area on record to be 9.6 mio km2 and it shows November 23rd as the date. Plus, as Wipneus wrote, we don't have data.

All charts show that there is a bit more ice now (excluding volume, cause these numbers are just area and extent, volume has its own thread) than a year ago(all area numbers plus JAXA and NSIDC extent, though NSIDC extent is really neck on neck race), some of them just show that last year had ice a bit more dispersed (bit more extent even if area is behind).

Since Uni Hamburg has no data before 2012, if you would put 2007,08,10 and 11 under 2018 as NSIDC shows, you would land on pretty much the same spot. (5th  + 4 = 9th)

And if I had to guess where that dispersion is, I would pick the Atlantic side of course, since this year we have the ice edge further north than in most (if not all) of the years before.

[gerontocrat]

JAXA & NSIDC data follow each other pretty closely, but my understanding is the AMSR2 resolution as used by JAXA is so much better than that on the NSIDC #F18 satellite that, especially when there is loads of slushy and low concentration ice around (as is the situation now), the JAXA data may well be more accurate.

But no matter what, I will continue to use both JAXA and NSIDC data (in separate analyses) until such time the scientific community say that a new benchmark is to be used.

Life is confusing enough already.

[Dharma Rupa]

JAXA & NSIDC data follow each other pretty closely, but my understanding is the AMSR2 resolution as used by JAXA is so much better than that on the NSIDC #F18 satellite that, especially when there is loads of slushy and low concentration ice around (as is the situation now), the JAXA data may well be more accurate.

But no matter what, I will continue to use both JAXA and NSIDC data (in separate analyses) until such time the scientific community say that a new benchmark is to be used.

Life is confusing enough already.

I think the word you are looking for is "incommensurable"

[gerontocrat]

I am moving my thoughts on this to "When Will The Arctic Go Ice Free" after this posting, apart from occasional posts on sea ice vs. open water as at the current date.

TRENDS IN OPEN WATER AS A PERCENTAGE OF ARCTIC SEAS AREA

After some false starts, and with some help from comments received, herewith the first graphs of "a new metric that belongs to me".

First, the definition and calculation methodology.

Basis of The Chosen Measure
Sea Ice Area is the measure that best shows for each of the 14 Arctic Seas (and the Arctic Ocean in total) the amount of the ocean covered by ice. It is that measure as a proportion of the total area of the ocean that indicates the balance between a maritime or sea-ice climate environment. So the total area of each sea is the measure against which sea ice area is to be measured.

Calculating the measure of “Atlantification” or “Pacification”? (or in general the trend to a maritime sea environment).

This is the simplest part.
1.    Average Daily Ice Area for each year = Sum of the area for the 365 days of the year and  divide by 365
2.   Divide by the area of the sea to give the proportion of sea covered by ice during the year.
3.   Then Open Water Percentage is 1 minus the proportion of sea covered by ice during the year expressed as a percentage.
This has also been done for
- March, when sea ice is at the maximum,
- September, when sea ice is at the minimum,
- The year to date, to justify posting onto the Extent and Area Data on the current thread.

Example Results 1979 to 2018 ( 4 graphs attached)

The Total Arctic graph is much as expected, gradual increases in open water in summer, winter and the total calendar year. This disguises great differences in individual seas. To note is that in September the proportion of open water has risen from 60% to 80%. Suddenly a BOE looks a bit closer.

The Baffin Sea, although a  peripheral sea, shows no trend to melt.

For the Central Arctic Sea (by far the largest) it is a story of losing ice in summer.

For the Barents Sea, our poster child for Atlantification, the loss of winter ice is dramatic.

[gerontocrat]

JAXA & NSIDC data follow each other pretty closely, but my understanding is the AMSR2 resolution as used by JAXA is so much better than that on the NSIDC #F18 satellite that, especially when there is loads of slushy and low concentration ice around (as is the situation now), the JAXA data may well be more accurate.

But no matter what, I will continue to use both JAXA and NSIDC data (in separate analyses) until such time the scientific community say that a new benchmark is to be used.

Life is confusing enough already.

I think the word you are looking for is "incommensurable"

Sounds like a definition of life

incommensurable

adjective
1.
not able to be judged by the same standards; having no common standard of measurement.
"the EDIT two many types of EDIT science just about anything: are incommensurable and thus cannot be integrated"
2.
MATHEMATICS
(of numbers) in a ratio that cannot be expressed as a ratio of integers.
noun
1.
an incommensurable quantity.

[Juan C. García]

[ADS-NIPR-JAXA] ASI Extent.

September 12^th, 2018: 4,545,005 km², a drop of -26,168 km².
2018 is the 8^th lowest on record.

[Wherestheice]

Wonder how long the melt will continue.... The Arctic could drop to 4th/5th/6th here soon if it does continue

[oren]

TRENDS IN OPEN WATER AS A PERCENTAGE OF ARCTIC SEAS AREA

I am sure I speak not just for myself - thank you for this wonderful analysis.

[Wipneus]

More to get confused, here are my Jaxa AMSR2 numbers (no ADS/NIPR/IJIS, Jaxa level 3 sea ice concentration (10x10km grid) used in my calculation of extent and area, no averaging whatsoever).

Jaxa extent.
1 "20120915" 3.209009
2 "20160902" 3.979547
3 "20150913" 4.259656
4 "20180911" 4.435505
5 "20170909" 4.461843
6 "20130912" 4.818514
7 "20140915" 4.901092

Jaxa Area
1 "20120912" 2.658249
2 "20160902" 3.08724
3 "20150907" 3.610253
4 "20180908" 3.85872
5 "20170905" 3.89612
6 "20140908" 4.242224
7 "20130909" 4.30679

[oren]

Thank you Wipneus for clarifying the data situation.
May I remind everyone who thinks 2012 was a statistical fluke, to look at 2016's JAXA area and see how far it was from other years and how (relatively) close it was to 2012.

[Rob Dekker]

More to get confused, here are my Jaxa AMSR2 numbers (no ADS/NIPR/IJIS, Jaxa level 3 sea ice concentration (10x10km grid) used in my calculation of extent and area, no averaging whatsoever).

Jaxa extent.
1 "20120915" 3.209009
2 "20160902" 3.979547
3 "20150913" 4.259656
4 "20180911" 4.435505
5 "20170909" 4.461843
6 "20130912" 4.818514
7 "20140915" 4.901092

Wipneus, I'm confused.
Juan Garcia just posted this :



Why are your JAXA numbers different from Juan Garcia's JAXA numbers ?

[gerontocrat]

JAXA ARCTIC EXTENT  4,545,005 km2（September 12, 2018）

Just to add to Juan's post...
- Extent is now 161 k km2  (3.6%) above the 2010's average extent and 42 k (0.9%) above 2017 on this date. (2017 was past its minimum by now, i.e. extent was increasing)
- Extent loss to date is now a very large 557 k km2 (5.6 %) below the 2008-2017 average.

The resulting minimum from average remaining melt is 4.51 million km2. Range of results from last ten years remaining melt is 4.36 to 4.55 million km2. 

Now maybe is the time to switch a lot of the attention to which seas continue melting and which commence refreeze.

[Krakatoa]

More to get confused, here are my Jaxa AMSR2 numbers (no ADS/NIPR/IJIS, Jaxa level 3 sea ice concentration (10x10km grid) used in my calculation of extent and area, no averaging whatsoever).

Jaxa extent.
1 "20120915" 3.209009
2 "20160902" 3.979547
3 "20150913" 4.259656
4 "20180911" 4.435505
5 "20170909" 4.461843
6 "20130912" 4.818514
7 "20140915" 4.901092

Wipneus, I'm confused.
Juan Garcia just posted this :



Why are your JAXA numbers different from Juan Garcia's JAXA numbers ?

Check the dates. Wipneus shows the minimum and Juan Garcia shows the data on September 12.

[colchonero]

Check the dates. Wipneus shows the minimum and Juan Garcia shows the data on September 12.

No that's not it. Wipneus' chart shows 2012 at 3.209  and Juan's shows 2012 at 3.206 . So it clearly can't be the minimum. As Wipneus said, his JAXA chart doesn't include something, but I'm not an expert in that field, so I can't explain exactly what

[oren]

Wipneus is using the same raw data but is removing a layer of filtering and averaging, and perhaps adding his own (better) filtering algorithm.

[Juan C. García]

The ADS/NIPR numbers are as they are. They undoubtedly use Jaxa data, but which data and how it is processed I have not been able to figure out.

I think that the data comes from different sources and that is the reason to have the differences. Wipneus data is directly from JAXA, while the data that I published is from JAXA, but changed by ADS/NIPR. Wipneus data is the minimum of the year for JAXA (3.209 on Sep 15, 2012). The ADS/NIPR minimum is lower (3,177M km2 for Sep 16, 2012). No Wipneus, no me, know all about the ADS/NIPR algorithm.

The 3.207M km2 is ADS/NIPR for Sep 12, 2012. I'm comparing the values for the last day that we have on 2018, not the minimums.

[colchonero]

Does the Wipneus data only have the last 7 years(from starting with 2012)?

[Wipneus]

Trying to minimize the confusion, let me confirm

- My lists are annual minimums, Juan lists are all the same date.

- AMSR2 started operating in 2012, NSIDC data is available from November 1978.

- Juan's "Jaxa" data are prepared by ADS/NIPR using data from Jaxa. Which data that actually is (brightness data? sea ice concentration data? which level (Level 2 is swath data, Level 3 is on a grid, two grids available)), I do not know. Neither do I know the details of the extent calculation and whether/how they have homogenized the older data from SMMR, SSM/I, SSMIS, AMSR-E and Windsat.

- I have not been able to reproduce the ADS/NIPR extent numbers accurately, like I did with the Cryosphere Today numbers.  That is a situation that I do not really like, but for now a fact.

- to add to the confusion, there is yet another Jaxa extent. My impression is that it is a calculation done all by Jaxa (any department). It is a five day average, which is enough to make it different from all other extents. Data needs free registration here:
http://kuroshio.eorc.jaxa.jp/JASMES/climate/index.html
Rough graph is here:

[gerontocrat]

NSIDC Total Area as at 12 September (5 day trailing average) =  3,201,385  km2

This is down to 148 k above the 2010-2017 average total area for this date
NOTE: The minimum area of the 2010-17 average was reached on 10th September

Total Area loss             9 k , 12 k above average for the day,

Central Seas loss         10 k,                                 
Peripheral Seas gain    1 k, all seas <5% of max.
Other Seas loss           0 k, all seas <5% of max.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 3 k, area 28 k, < 5% of max.
Atlantic Side
- Baffin Sea gain 1 k, area 22 k, <5% of max,
- Greenland Sea gain 0 k km2 , area 55 k,
- Barents Sea - finished,
- The Kara Sea area loss 0 k, area 27 k, < 5% of maximum.
- The Laptev Sea area gain 1 k, area 13 k, <5% of maximum.

CAB
- Beaufort Sea loss 1 k,
- The Canadian Archipelago loss 4 k,
- East Siberian Sea loss 8 k .
- The Central Arctic Sea gain 5 k

Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0 k, Area  7 k,
- The Okhotsk Sea - finished .

Eastern Siberian Sea still losing ice - graph attached.

The season is nearly over. Nowt to do but watch day by day.
[/quote]

[gerontocrat]

Too many datasets about the same thing - the sea ice.

Me, I am going to stick with:

JAXA daily extent,
NSIDC 5-day trailing average area to look at individual seas.

because these are the datasets on which  built the little database inside my laptop and consistency is perhaps more important for my analyses than the search for greater accuracy.

Mind you, with ice-sat2 being launched on September 15, there may well be a new benchmark being established over time.

[Pmt111500]

Too many datasets about the same thing - the sea ice.

Demands of absolute certainty are always funny when it comes to science, and not saying you're demanding it.

[Ned W]

Wonder how long the melt will continue.... The Arctic could drop to 4th/5th/6th here soon if it does continue

For JAXA extent, 6th is most likely (53%), followed by 8th (27%) and 7th (20%). 

4th or 5th would be extremely unlikely (under 1% chance). 

The big question is whether we end up below last year, or above.  Pretty close to 50-50 right now.

[gerontocrat]

You may have seen my recent posts on comparing sea ice area with the total area of each arctic sea to give the open water percentage. I emailed NSIDC to get the area of each of the Arctic Seas as defined in the NSIDC spreadsheets, as some seas,e.g. Greenland Sea, are partly bounded by the ice free ocean.

I also asked them if there was a plan in place for if/when the last satellite DMSP F-18 fails (it is operating beyond its design life).

Here is the reply.

Hi Matthew,

Thank you for contacting NSIDC. We have not documented the area of each sea ice region. However, we do have tools for you to do this, and they are described in the documentation at
https://nsidc.org/sites/nsidc.org/files/files/data/noaa/g02135/Sea-Ice-Analysis-Spreadsheets-Overview.pdf

As for the satellite series, we are investigating the alternatives, but we don't have any information published yet.

Please let me know if you have additional questions.

Best regards,
Lisa
NSIDC User Services
CIRES, 449 UCB
University of Colorado

I admit to being taken aback that such a basic piece of data is not available. I have not the skills to do it myself. The last fortran programme I wrote was in 1975 in Ffortran IV  for an IBM-360 mainframe with 64kb memory including a 12kb operating system. Those were the days.

I also admit that I am not entirely reassured by the reply on plans to keep the NSIDC data series going if that satellite goes kaput. One satellite, one sensor. That's all we've got.

[TerryM]

TRENDS IN OPEN WATER AS A PERCENTAGE OF ARCTIC SEAS AREA

I am sure I speak not just for myself - thank you for this wonderful analysis.

Good Stuff!!
Appreciated by all
Terry

[Juan C. García]

[ADS-NIPR-JAXA] ASI Extent.

September 13^th, 2018: 4,583,173 km², an increase of 38,168 km².
2018 is the 8^th lowest on record.

[Cid_Yama]

I have always gone with the AMSR.  E then 2.

https://seaice.uni-bremen.de/data/amsr2/today/extent_n_running_mean_amsr2_previous.png

https://seaice.uni-bremen.de/data/amsr2/today/extent_n_running_mean_amsr2_regular.png

I think I'll stick with the recognized sources.

The agenda of anonymous individuals on the internet remain suspect. (Except Wipneus who seems clearly apolitical, and unbiased.)  No insult intended.

American data sources are clearly suspect.  Especially during an election year.  The people we could trust were all purged.   

[gerontocrat]

JAXA ARCTIC EXTENT 4,583,173 km2（September 13, 2018）

Just to add to Juan's post...
- The increase in extent of 38k was well above average,
- Extent is now 203 k km2  (4.4%) above the 2010's average extent and 89 k (1.9%) above 2017 on this date. (2017 was past its minimum by now, i.e. extent was increasing)
- Extent loss to date is now a very large 597 k km2 (6.0 %) below the 2008-2017 average.

The resulting minimum from average remaining melt is 4.56 million km2, which is an invalid result. The spreadsheet loses its integrity when extent is dithering around the minimum (or the maximum). Range of results from last ten years remaining melt is 4.40 to 4.55 million km2. 

Now is the time to switch the attention to which seas continue melting and which commence refreeze (which probably means there will be a late burst of melt to make me wrong again).

[Ned W]

The resulting minimum from average remaining melt is 4.56 million km2, which is an invalid result. The spreadsheet loses its integrity when extent is dithering around the minimum (or the maximum). Range of results from last ten years remaining melt is 4.40 to 4.55 million km2. 

Hmm.  If you're looking at the last 10 years, then in six of the past ten years the minimum had been reached by this date, meaning there was 0 remaining melt.  In the other four years, there was still ice loss, which could be measured either in terms of the difference between today's value and the final minimum, or the difference between the minimum-to-date and the final minimum.  Using those two methods (call them A and B, respectively) and averaging in the six years of zero remaining melt, I get:

Resulting minimum from average remaining melt over the past 10 years = 4.53 (both methods)
Range of results from the past 10 years = 4.40 (A) or 4.45 (B), to 4.55 (both).  No invalid results, and no loss of integrity.  You just need to set the remaining melt to 0 for any year that has already reached its minimum.

[gerontocrat]

Hmm.  If you're looking at the last 10 years, then in six of the past ten years the minimum had been reached by this date, meaning there was 0 remaining melt.  In the other four years, there was still ice loss, which could be measured either in terms of the difference between today's value and the final minimum, or the difference between the minimum-to-date and the final minimum.  Using those two methods (call them A and B, respectively) and averaging in the six years of zero remaining melt, I get:

Resulting minimum from average remaining melt over the past 10 years = 4.53 (both methods)
Range of results from the past 10 years = 4.40 (A) or 4.45 (B), to 4.55 (both).  No invalid results, and no loss of integrity.  You just need to set the remaining melt to 0 for any year that has already reached its minimum.

The loss of integrity in looking forward to further extent loss is because "in six of the past ten years the minimum had been reached by this date, meaning there was 0 remaining melt. ". In other words, extent gain from this date is as likely, or more likely, than extent loss. So the minimum could well be the extent on Sept 12th.

So from now my posts will be silent on further extent loss (or gain) possibilities.

[gerontocrat]

NSIDC Total Area as at 13 September (5 day trailing average) =  3,199,720  km2

This is down to 125 k above the 2010-2017 average total area for this date
NOTE: The minimum area of the 2010-17 average was reached on 10th September, i.e. average now gains in ice
 3,199,720    -1,665     982    -2,186    -461

Total Area loss             2 k , 12 k above average for the day,

Central Seas loss         2 k,                                 
Peripheral Seas gain    1 k, all seas <5% of max.
Other Seas loss           0 k, all seas <5% of max.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 2 k, area 25 k, < 5% of max.
Atlantic Side
- Baffin Sea gain 1 k, area 23 k, <5% of max,
- Greenland Sea gain 0 k km2 , area 55 k,
- Barents Sea - finished,
- The Kara Sea area gain 1 k, area 28 k, < 5% of maximum.
- The Laptev Sea area gain 1 k, area 14 k, <5% of maximum.

CAB
- Beaufort Sea gain 3 k,
- The Canadian Archipelago loss 4 k,
- East Siberian Sea loss 6 k .
- The Central Arctic Sea gain 5 k

Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0.5 k, Area  6 k,
- The Okhotsk Sea - finished .

The season is nearly over. Nowt to do but watch day by day.

[Juan C. García]

[ADS-NIPR-JAXA] ASI Extent.

September 14^th, 2018: 4,570,758 km², a drop of -12,415 km².
2018 is the 8^th lowest on record.

[gerontocrat]

JAXA ARCTIC EXTENT 4,570,758 km2（September 14, 2018）

Just to add to Juan's post...

- Extent is now 181 k km2  (4.0%) above the 2010's average extent and 72 k (1.6%) above 2017 on this date.
- Extent loss to date may now be irrelevant as the minimum (4.55 million km2) may have happened on September 12.

The spreadsheet loses its integrity when extent is dithering around the minimum. However, if the remaining melt in 2010 was repeated this year the minimum would be  4.41 million km2. 

[gerontocrat]

NSIDC Total Area as at 14 September (5 day trailing average) = 3,210,664 km2

This is down to 104 k above the 2010-2017 average total area for this date

I think that maybe the melting season is done (at least on this measure)

Total Area GAIN 11 k ,

Central Seas GAIN    11 k,                                 
Peripheral Seas gain    0 k, all seas <5% of max.
Other Seas loss           0 k, all seas <5% of max.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 4 k, area 22 k, < 5% of max.
Atlantic Side
- Baffin Sea gain 0 k, area 23 k, <5% of max,
- Greenland Sea gain 0 k km2 , area 55 k,
- Barents Sea - finished,
- The Kara Sea area gain 1 k, area 29 k, < 5% of maximum.
- The Laptev Sea area gain 1 k, area 15 k, <5% of maximum.

CAB
- Beaufort Sea gain 7 k,
- The Canadian Archipelago loss 2 k,
- East Siberian Sea loss 7 k .
- The Central Arctic Sea gain 14 k

Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0.5 k, Area  6 k,
- The Okhotsk Sea - finished .

The season is nearly over. Nowt to do but watch day by day to see which seas still melt, which gain.

[Stephan]

ESS is still losing ice day by day. I wonder how long this will go on...

[Juan C. García]

[ADS-NIPR-JAXA] ASI Extent.

September 15^th, 2018: 4,546,800 km², a drop of -23,958 km².
2018 is the 8^th lowest on record.

PS: The 2018 mínimum continues to be September 12^th with 4,545,005 km², a difference of only 1,795 km² with today's value.
.
 

[gerontocrat]

JAXA ARCTIC EXTENT 4,546,800 km2（September 15, 2018）

Just to add to Juan's post...

- Extent is now 142 k km2  (3.1 %) above the 2010's average extent and 6 k (0.1%) above 2017 on this date (2018 extent loss & 2017 extent gain on the day).
- The minimum (4.55 million km2) may have happened on September 12.

The spreadsheet loses its integrity when extent is dithering around the minimum. However, if the remaining melt in 2010 was repeated this year the minimum would be  4.43 million km2.

[gerontocrat]

NSIDC Total Area as at 15 September (5 day trailing average) = 3,224,398 km2

This is down to EDIT - whoops 834 83k above the 2010-2017 average total area for this date

I think that maybe the melting season is done (on this measure - not on extent)

Total Area GAIN 14 k ,

Central Seas GAIN    14 k,                                 
Peripheral Seas gain    0 k, all seas <5% of max.
Other Seas loss           0 k, all seas <5% of max.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 4 k, area 17 k, < 5% of max.
Atlantic Side
- Baffin Sea loss 1 k, area 22 k, <5% of max,
- Greenland Sea gain 0 k km2 , area 55 k,
- Barents Sea - finished,
- The Kara Sea area gain 0 k, area 29 k, < 5% of maximum.
- The Laptev Sea area gain 1 k, area 16 k, <5% of maximum.

CAB
- Beaufort Sea gain 12 k,
- The Canadian Archipelago gain 1 k,
- East Siberian Sea loss 6 k .
- The Central Arctic Sea gain 10 k

Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0 k, Area  6 k,
- The Okhotsk Sea - finished .

The season is nearly over. Nowt to do but watch day by day to see which seas still melt (currently the Chukchi and ESS), and which gain. There may be more surprises.

There is a contrast with Daily Extent - that has lost 87k on this day, and 35k the day before, and is below the 2017 minimum by 75 k.

[gerontocrat]

Here are the latest area graphs for the Chukchi and the ESS, the last two seas losing area of any consequence.

[Steven]

NSIDC daily sea ice area is currently 3.26 million km2, which is 6th lowest for the date:



The minimum this year (so far) was 3.16 million km2 on 9 September 2018, which is the 9th lowest minimum on record, as already posted upthread:

Here are the area numbers.

NSIDC:
NH Area
1 2012-09-12 2.228429
2 2016-09-07 2.400654
3 2011-09-05 2.916451
4 2017-09-11 2.939311
5 2007-09-07 2.952352
6 2010-09-07 3.071674
7 2008-09-08 3.079552
8 2015-09-07 3.139137
9 2018-09-09 3.156973
10 2009-09-08 3.547109

[Hautbois]

Running back chart update. 2018 showing how to fake left then go right. 

[NACK]

It makes it clear that there is a difference...I guess noting the way the lines bend at the decade is a bit too pedantic.

This is fine.

The data is arranged so I can do the time series for each year from 1980 without too much grief.
Probably the second effort when phase 1 is done. But also (Neven's 4 regions) vs. Atlantic periphery, Pacific periphery, the CAB and those 3 seas not really connected to the Arctic Ocean (Lawrence, Okhotsk, Hudson)) to consider.

But here a taster of phase 2

But cut some slack to this poor clapped out analyst and his poor clapped out laptop. Weep, sniffle, reach for handkerchief.

Genocrat,

Did you notice that the total arctic chart, over the last couple of decades, indicates an approximate 4-year cyclical feature that I found interesting. Does anyone have any possible explanation of this curious feature.

I would really like to see an area specific chart of the CAA if possible.

[gerontocrat]

Genocrat,

Did you notice that the total arctic chart, over the last couple of decades, indicates an approximate 4-year cyclical feature that I found interesting. Does anyone have any possible explanation of this curious feature.

I would really like to see an area specific chart of the CAA if possible.

Go to "when will the arctic  go ice-free" thread for all my postings on this over the last few days.

[Juan C. García]

[ADS-NIPR-JAXA] ASI Extent.

September 16^th, 2018: 4,513,511 km², a drop of -33,289 km².
2018 is the 6^th lowest on record.

[Juan C. García]

[ADS-NIPR-JAXA] ASI Minimum extent by year.

Data until September 16^th, 2018:

[Sterks]

Given the weather conditions, the last table may end placing 2018 to 6th as well, but anything can happen (does it really matter?)
Thank you Juan Carlos and Gerontocrat (and the rest that add value here) for keeping us so well informed every day.

[gerontocrat]

JAXA ARCTIC EXTENT 4,513,511 km2（September 16, 2018）

Just to add to Juan's post...

- Extent is now 114 k km2  (2.5 %) above the 2010's average extent and 64 k (1.4%) below 2017 on this date (2018 extent loss & 2017 extent gain on the day).
- It is a new minimum (4.51 million km2).

However, if the remaining melt in 2010 was repeated this year the minimum would be 4.45 million km2, causing anguish to a few pollsters and joy to others.

Any more surprises in store?

[gerontocrat]

NSIDC Total Area as at 16 September (5 day trailing average) = 3,233,213  km2

This is down to 58 k above 2010-2017 and 4k less than 2017 for this date

I think that maybe the melting season is done (on this measure - not on extent)

Total Area GAIN 9 k ,

Central Seas GAIN      7 k,                                 
Peripheral Seas gain    2 k, all seas <5% of max.
Other Seas loss           0 k, all seas <5% of max.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 3 k, area 15 k, < 5% of max.
Atlantic Side
- Baffin Sea loss 0 k, area 23 k, <5% of max,
- Greenland Sea gain 1 k km2 , area 56 k,
- Barents Sea - finished,
- The Kara Sea area loss 1 k, area 28 k, < 5% of maximum.
- The Laptev Sea area gain 0 k, area 17 k, <5% of maximum.

CAB
- Beaufort Sea gain 12 k,
- The Canadian Archipelago gain 0 k,
- East Siberian Sea loss 3 k .
- The Central Arctic Sea gain 2 k

Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0 k, Area  6 k,
- The Okhotsk Sea - finished .

The season is nearly over. Nowt to do but watch day by day to see which seas still melt (currently the Chukchi and ESS), and which gain. There may be more surprises.

There is a contrast with Daily Extent - that has lost 7k on this day, and 87k, 35k the days before, and the 5 day trailing average extent is below the 2017 minimum by 90 k.

[Juan C. García]

I am not having access to ADS-NIPR page...
There will be not update from myself until tomorrow (It is 11:00 pm in Mexico).
A shame! Today could be a new low… 

https://ads.nipr.ac.jp/vishop/#/extent