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Neven

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2018 sea ice area and extent data
« on: January 04, 2018, 04:50:55 PM »
Here's a new thread to replace the 2017 version.

Have at it, spread the data.

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Frosty

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Re: 2018 sea ice area and extent data
« Reply #1 on: January 05, 2018, 09:30:11 AM »
Obviously too early to draw any conclusions regarding what will happen this year.

That said, let us all take a moment to hope and pray for the best.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #2 on: January 05, 2018, 03:50:32 PM »
JAXA still not showing the graphs and the data for 2018, so I had a look at the NSIDC daily data spreadsheet.

This says extent on 4 Jan still 300 k km2 less than 4 Jan 2017, BUT extent stalled last year for a good few days from now.
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Tor Bejnar

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Re: 2018 sea ice area and extent data
« Reply #3 on: January 05, 2018, 07:43:07 PM »
Welcome to the posting world, Frosty.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #4 on: January 06, 2018, 07:55:07 PM »
JAXA still not showing the graphs and the data for 2018, so I had a look at the NSIDC daily data spreadsheet.

As at 5 Jan extent still lowest, but now by only about 150 k.
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Jim Pettit

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Re: 2018 sea ice area and extent data
« Reply #5 on: January 07, 2018, 02:27:37 PM »
NSIDC extent dropped quite a bit, pretty much removing yesterday's upward spike.



2017 extent barely grew over the second week of January, but shot upwards nearly a million km2 in the second half of the month. IOW, we can expect 2018 to fall into second place over the next day or two, and remain there until at least the 18th or so.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #6 on: January 07, 2018, 02:50:01 PM »
NSIDC extent dropped quite a bit, pretty much removing yesterday's upward spike.

2017 extent barely grew over the second week of January, but shot upwards nearly a million km2 in the second half of the month. IOW, we can expect 2018 to fall into second place over the next day or two, and remain there until at least the 18th or so.

From "aperson" on the freezing thread:-

Both GEFS and EPS ensembles are mostly in agreement on a synoptic setup that supports warm anomalies driven from subtropical advection on both the Atlantic and Pacific sides in the 5 day to 2 week mid range.

On the Pacific, a return of strong -EPO conditions starting around 5 days out will support another round of anomalies on the Pacific side. In the Atlantic, a strong pressure gradient along the NAO will transport subtropical moisture over the Greenland and Barents seas.

The 5 day cci-reanalyzer forecast also has both ends warming up.

So the question is - will this warmth slow down extent gain as in 2017, allowing 2018 to keep in first place to mid-month and later in the month to become ridiculously lower than 2017 ?
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #7 on: January 07, 2018, 03:10:52 PM »
JAXA 2018 data and extent graphs still not available., so I sent a polite e-mail to the Japanese National Institute of Polar Research to ask when it may appear.

Will they answer?
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Jim Pettit

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Re: 2018 sea ice area and extent data
« Reply #8 on: January 07, 2018, 10:25:08 PM »
JAXA 2018 data and extent graphs still not available., so I sent a polite e-mail to the Japanese National Institute of Polar Research to ask when it may appear.

Will they answer?

Not sure. But I follow their Twitter feed, and they're normally pretty good about keeping up-to-date in regard to outages. But there's been no such tweet lately, so I assume they're just on break, maybe?

A-Team

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Re: 2018 sea ice area and extent data
« Reply #9 on: January 08, 2018, 10:40:19 AM »
JAXA 2018 data and extent graphs still not available
Ditto NOAA's RASM-ESRL: it is still frozen on 26 Dec 17 with no advisory 13 days later about when or if it will resume. [[Update: forecasts to resume 14 Feb 18]]

The attached image, adapted form @zlabe, wraps up 2017 extent for the Chukchi. The definition of that sea is elusive, with boundary definitions varying widely by source. The inset shows a common choice that may be what NSIDC used for the data.

Researchers at NSIDC often do not use this boundary in their journal articles, more often taking a contour line such as -150 m as the northern extent, which makes more oceanographic sense than a latitude line oblivious to bathymetric shelves and basins. It is also common to see no definition, simply Chukchi text floating conceptually north of the Bering Strait.

The scale has been changed to percent of maximal possible extent as this is more to the point of seasonally ice-free. By pixel counts, 63% of maximal extent was realized over the year but only 44% over May-Dec and similarly over the insolation season. So we are about halfway there to 'seasonally ice extent-free' for the Chukchi and many of the consequences will have set in already.

On the admin oddities front, it appears that "viewed n times" is not working today.
« Last Edit: January 09, 2018, 04:18:55 PM by A-Team »

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #10 on: January 08, 2018, 12:55:49 PM »
JAXA 2018 data and extent graphs still not available., so I sent a polite e-mail to the Japanese National Institute of Polar Research to ask when it may appear.

Will they answer?

Not sure. But I follow their Twitter feed, and they're normally pretty good about keeping up-to-date in regard to outages. But there's been no such tweet lately, so I assume they're just on break, maybe?
Japan does well for National Holidays. Perhaps tomorrow may see some scientists and technicians stagger into work.
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Jim Pettit

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Re: 2018 sea ice area and extent data
« Reply #11 on: January 08, 2018, 02:07:03 PM »
NSIDC extent down yet again:

Click for up-to-date, full-size image:


Of course, record low winter extent doesn't mean record low summer extent (see: 2017).
« Last Edit: January 08, 2018, 02:36:24 PM by Jim Pettit »

Gray-Wolf

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Re: 2018 sea ice area and extent data
« Reply #12 on: January 08, 2018, 02:22:18 PM »
NSIDC extent down yet again:

Of course, record low winter extent doesn't mean record low summer extent (see: 2017).

Hi Jim!

Yes I think that we are seeing more of our degradation of the pack over the winter now with changes to the summer weather over the pack meaning the type of 07'/2012' summers are no longer there
In some ways this is far worse as a 'perfect melt storm' leading to a blue ocean event would see some recovery the following year
(if that pattern of weather does not repeat the following summer?)
Our pathway now will mean that a poor summer for melt/export will still lead to the blue ocean event and then it will probably repeat thereafter with only exceptional years retaining the 'over the million' in ice cover all summer?

That said I do see this as an ongoing change to summer weather over the basin as more heat/moisture becomes available so who knows what comes next?
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #13 on: January 08, 2018, 03:26:20 PM »
Last year at about this time, due to the slow 2017 extent gain in the Arctic,  there was discussion about the relative importance of sea ice loss in summer and winter, especially given that the September extent minimum has been going down at about 12.5 % per decade while the March maximum only at about 2.5 % per decade.

The question is - are we seeing an acceleration of winter extent loss ? If so, that leads to the question as to the relative importance of the oceans and the atmosphere, and then to what does this mean for summer ice.

Trouble is, I haven't the faintest idea of how to answer any of these questions.
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RikW

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Re: 2018 sea ice area and extent data
« Reply #14 on: January 09, 2018, 09:10:22 AM »
I still think in March extent will be low, and I guess we have a good (or bad...) chance it will be a record again, but I think the polar night will be so cold for decades to come, and the ocean not warm enough, that the top layer will still freeze, but it will lack thickness. But it is just a gut feeling/ based on simple logic without thorough understanding of all mechanics.

Neven

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Re: 2018 sea ice area and extent data
« Reply #15 on: January 09, 2018, 12:45:11 PM »
I had received an e-mail stating that something had been changed in the JAXA SIE data sheet, but now the ADS NIPR site can't be reached. Has anyone seen whether data had been updated? I know it's winter/hibernation time, but 10 days of no data is too much!  ;)
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #16 on: January 09, 2018, 01:25:50 PM »
I had received an e-mail stating that something had been changed in the JAXA SIE data sheet, but now the ADS NIPR site can't be reached. Has anyone seen whether data had been updated? I know it's winter/hibernation time, but 10 days of no data is too much!  ;)
I am encouraged that the site is now down - perhaps that means they are trying to fix the problem.

Meanwhile, my spreadsheets are dying from data malnutrition.
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Pmt111500

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Re: 2018 sea ice area and extent data
« Reply #17 on: January 09, 2018, 01:36:03 PM »
Hey-ho, we may still book passenger flights crossing arctic to get data :P .  Remember tuesday updates on windows-machines may be a bit more tricky this time around. For sure, some of JAXA stuff runs on Linux, but will the updates talk to each other?
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A-Team

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Re: 2018 sea ice area and extent data
« Reply #18 on: January 09, 2018, 04:27:00 PM »
10 days of no data is too much!
RASM_ESRL to resume its forecasts on 14 Feb 18. After a 50 day hiatus! No word on whether they will infill missing data days nor if algorithm is changing (and backwards-comparable). Possibly a good window to get in comments, feature requests and bug reports. Email contacts on web page.

https://www.esrl.noaa.gov/psd/forecasts/seaice/

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #19 on: January 09, 2018, 09:20:01 PM »
10 days of no data is too much!
RASM_ESRL to resume its forecasts on 14 Feb 18. After a 50 day hiatus! No word on whether they will infill missing data days nor if algorithm is changing (and backwards-comparable). Possibly a good window to get in comments, feature requests and bug reports. Email contacts on web page.

https://www.esrl.noaa.gov/psd/forecasts/seaice/
Life must be very difficult at NOAA at the moment - they still do not know how much they will be clobbered when the 2018 Federal Budget is decided. I understand that at the moment they are on 2017 pro-rata budget levels. Something might be decided at overall level in the next 10 days.
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DavidR

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Re: 2018 sea ice area and extent data
« Reply #20 on: January 09, 2018, 11:01:52 PM »
Hey-ho, we may still book passenger flights crossing arctic to get data :P .  Remember tuesday updates on windows-machines may be a bit more tricky this time around. For sure, some of JAXA stuff runs on Linux, but will the updates talk to each other?

Recently flew Tokyo to London and noticed that the plane did not cross into the Arctic despite it being the shortest route. so don’t go booking Arctic flights without checking if the plane goes there. is avoiding the Arctic normal practice for commercial jets?

Neven

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Re: 2018 sea ice area and extent data
« Reply #21 on: January 09, 2018, 11:30:39 PM »
I had another look at what numbers had changed in the JAXA SIE data file, so here's a provisional graph:
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Pmt111500

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Re: 2018 sea ice area and extent data
« Reply #22 on: January 10, 2018, 02:28:11 AM »
Hey-ho, we may still book passenger flights crossing arctic to get data :P .  Remember tuesday updates on windows-machines may be a bit more tricky this time around. For sure, some of JAXA stuff runs on Linux, but will the updates talk to each other?

Recently flew Tokyo to London and noticed that the plane did not cross into the Arctic despite it being the shortest route. so don’t go booking Arctic flights without checking if the plane goes there. is avoiding the Arctic normal practice for commercial jets?

Not in summer at least, i don't know of winters... Could of course be a matter of jet streams, the airlines like to use'em to save in fuel. Flying counterclockwise this might be more of an issue.
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Phil.

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Re: 2018 sea ice area and extent data
« Reply #23 on: January 10, 2018, 04:34:25 AM »
Definitely if you can get in the jet stream uses a lot less fuel and saves time, similarly if flying from London to NY you'd want to avoid it.

binntho

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Re: 2018 sea ice area and extent data
« Reply #24 on: January 10, 2018, 08:00:08 AM »
Well Jaxa is up and running again.

A-Team

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Re: 2018 sea ice area and extent data
« Reply #25 on: January 10, 2018, 11:18:08 AM »
Jim Petit wrote back in #637 of 2017:  I spend a few daysof the new year tweaking all my graphs and charts. I've read the suggestions for changing the baselines and so on; any changes incorporating those suggestions will be made public in early January.
@zlabe linked to the definitive meteorological article used to justify climate baseline definitions, anomaly charts, and what to do during periods of rapidly changing baselines, first article below. It has been cited 131 times; I chased through those to find the best five, all free full text.

The Definition of the Standard MO Climate Normal
The Key to Deriving Alternative Climate Normals
by A Arguez and RS Vose
http://journals.ametsoc.org/doi/pdf/10.1175/2010BAMS2955.1
131 cites since 2011

NOAA's 1981–2010 US Climate normals: an overview
A Arguez et al
http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-11-00197.1

Projecting “Normals” in a Nonstationary Climate
DS Wilks
http://journals.ametsoc.org/doi/pdf/10.1175/JAMC-D-11-0267.1
Discussion of "hinge" functions to represent changing normals

Performance of Alternative Normals for Tracking Climate Changes, Using
Homogenized and Nonhomogenized Seasonal U.S. Surface Temperatures
DS Wilk RE Livezey
Considers eleven alternatives to the annually updated 30-yr average for specifying climate normals

How well must climate models agree with observations?
D. Notz 2015
http://rsta.royalsocietypublishing.org/content/373/2052/20140164
Arctic sea ice-free timing used to illustrate ideas

Public Perception of Climate Change and the New Climate Dice
J Hansen M Sato R Ruedy
https://arxiv.org/pdf/1204.1286.pdf

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #26 on: January 10, 2018, 02:31:24 PM »
JAXA DATA AS AT 9 JAN 2018.   Hoorah..

                        Whoops !
Although extent loss   gain on average is 85% done, there is on average 66 days to go to maximum. Extent is still just lowest in the satellite record.

Historical data suggests a low or record low maximum, but over the last 10 years maximum has been reached any time from the 2nd to 31st March.

cci-reanalyzer forecasts high temp anomalies in the Arctic for the next five days, especially at both ends (Pacific and Atlantic) , weather-forecast.com shows a big push of wind from the South into the far north Atlantic this week and continuing stormy weather in the Bering Sea.  Slow or zero extent gain over the next few days ?
« Last Edit: January 10, 2018, 09:26:44 PM by gerontocrat »
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gregcharles

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Re: 2018 sea ice area and extent data
« Reply #27 on: January 13, 2018, 04:52:01 AM »
I'm trying to post my first image! It's the count of days for each year with the lowest JAXA (or NIPR or VISHOP) extent number for its date. 2018 has 11 first places finishes in 11 days. It looks like it will probably move to second for the next couple of days, then maybe get first place back.


gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #28 on: January 13, 2018, 11:51:06 AM »
JAXA DATA AS AT 12 JAN 2018.   Hoorah..

Extent gain on average is 86% done, there is on average 62 days to go to maximum. Extent is still just lowest in the satellite record, and as commented above, is likely to be second on the 13th for a couple of days, and then possibly to be lowest again.

Historical data still strongly suggests a low or record low maximum. We will see.
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Jim Pettit

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Re: 2018 sea ice area and extent data
« Reply #29 on: January 13, 2018, 02:28:44 PM »
JAXA DATA AS AT 12 JAN 2018.   Hoorah..

Extent gain on average is 86% done, there is on average 62 days to go to maximum. Extent is still just lowest in the satellite record, and as commented above, is likely to be second on the 13th for a couple of days, and then possibly to be lowest again.

Historical data still strongly suggests a low or record low maximum. We will see.

At the moment, a record low maximum is likely, though not a certainty:

Click for most recent full-size image:

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #30 on: January 15, 2018, 01:38:44 PM »
JAXA extent at 14 Jan now 90K km2 greater than 2017. This could easily change over the next week, as the graph indicates. A record low remains on the cards.
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DavidR

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Re: 2018 sea ice area and extent data
« Reply #31 on: January 16, 2018, 08:12:46 AM »
The third biggest January increase in the JAXA record has 2018 leaping by over 151K putting it well behind 2017 for the moment but still comfortably in second place. 

2006 is now the big challenger as it takes over as lowest on record on the 19th for 8 days.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #32 on: January 18, 2018, 08:27:07 PM »
JAXA DATA as at 17 Jan

150k increase immediately followed by 34 kn and 11k. Result ? No real change.
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