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Author Topic: Latest PIOMAS update (September, mid-monthly update)  (Read 1493666 times)

Wipneus

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Re: Latest PIOMAS update (June)
« Reply #3650 on: June 04, 2021, 06:28:37 PM »
PIOMAS gridded thickness data was updated to the 31st of May (day 151 of 2021).
Volume calculated form this thickness was 19,76 [1000km3], which is the 7th lowest value for that day of the year.

Here is the animation for May 2021:

Wipneus

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Re: Latest PIOMAS update (June)
« Reply #3651 on: June 04, 2021, 06:31:49 PM »
The update Fram volume export graph.

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Re: Latest PIOMAS update (June)
« Reply #3652 on: June 04, 2021, 06:34:07 PM »
The updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (June)
« Reply #3653 on: June 04, 2021, 06:37:40 PM »
Thickness map, compared with previous years and their diff's.

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gerontocrat

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Re: Latest PIOMAS update (June)
« Reply #3655 on: June 05, 2021, 09:02:52 PM »
Here's hoping this is good use of the Wipneus data

PIOMAS  Volume as at 31 May 2021  19,761 KM3

- Volume loss from maximum on this date is 2,789 km3, 272 km3, (9%),  less than the 10 year average of 3,061 km3.

- Volume is at position #7 in the satellite record

- Volume is  170 km3 MORE than 2012
- Volume is  1,665 km3 MORE than 2017
- Volume is  60 km3 MORE than 2020
- Volume is  53 km3 LESS than 2010's average
Projections.

Average remaining volume loss (of the last 10 years) would produce a minimum volume in Sept 2021 of 4,788 km3, 1,115 km3 above the 2012 record low minimum volume of 3,673 km3.

This minimum would be 8th lowest in the 43 year satellite record.
___________________________________________________________
N.B. Click on image  for full-size
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cesium62

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Re: Latest PIOMAS update (June)
« Reply #3656 on: June 10, 2021, 10:26:04 AM »
If others want to use a different approach please have a go - the data is there courtesy of Wipneus & Dr. Zhang of the Polar Science Center.

The graph attributed to you shows 2012 sep monthly volume below 4.0.  Wipneus (https://sites.google.com/site/arctischepinguin/home/global-sea-ice  https://sites.google.com/site/arctischepinguin/home/giomas/data/giomas-sumdata.csv.txt?attredirects=0) shows 5.023.

So as long as you aren't expecting the raw data to be the same...  The following graphs have consistent trend lines.







gerontocrat

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Re: Latest PIOMAS update (June)
« Reply #3657 on: June 10, 2021, 11:28:02 AM »
If others want to use a different approach please have a go - the data is there courtesy of Wipneus & Dr. Zhang of the Polar Science Center.

The graph attributed to you shows 2012 sep monthly volume below 4.0.  Wipneus (https://sites.google.com/site/arctischepinguin/home/global-sea-ice  https://sites.google.com/site/arctischepinguin/home/giomas/data/giomas-sumdata.csv.txt?attredirects=0) shows 5.023.

So as long as you aren't expecting the raw data to be the same...  The following graphs have consistent trend lines.
We have a data problem.

The file you use says in the header data "# Last Update 2019/02/01" with as you say a Sep 2012 volume of 5.023

The monthly file from the Polar Science Center can be downloaded from http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/data/.

The Sep 2012 volume in this file is 3.78746

The monthly regional file from Wipneus which he provides every month is for each regional sea. The total September 2012 volume in that file is 3.788.

I think Wipneus has to have a look at that file. As far as I am concerned my data is consistent with the data directly from the Polar Science Center (who wrote the system, manage the system and produce the data) and the data that Wipneus then creates and sends the link to the ASIF once a month for monthly data and twice monthly for daily data.

I attach an image (click image to enlarge for readability) of the Polar Science center data and a .csv file.


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Re: Latest PIOMAS update (June)
« Reply #3658 on: June 11, 2021, 08:51:22 AM »

___________________________________________________
If others want to use a different approach please have a go - the data is there courtesy of Wipneus & Dr. Zhang of the Polar Science Center.

The graph attributed to you shows 2012 sep monthly volume below 4.0.  Wipneus (https://sites.google.com/site/arctischepinguin/home/global-sea-ice  https://sites.google.com/site/arctischepinguin/home/giomas/data/giomas-sumdata.csv.txt?attredirects=0) shows 5.023.

So as long as you aren't expecting the raw data to be the same...  The following graphs have consistent trend lines.

We have a data problem.

Please note the data is "giomas", not PIOMAS?

Giomas is the same idea as PIOMAS, same university group. It is older, has less resolution (expect less precision) yet is has global coverage (includes Southern Hemisphere). It is also less frequently updated, sometimes after a request from me.

G/P trends are comparable , I can agree with that.

oren

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Re: Latest PIOMAS update (June)
« Reply #3659 on: June 11, 2021, 09:07:52 AM »
Hello Wipneus, as usual many thanks for all the outputs of PIOMAS (as well as other data) you provide. I have a question/request - is it possible to generate a chart of export through the FJL/Svalbard gap, similar to the Fram export chart? It appears that lately this export is becoming quite important, due to the increased mobility of the ice in that sector of the CAB.
I notice that the 80N latitude circle between ~27E and ~47E can be defined as the approximate export line, which might make calculations easier.

gerontocrat

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Re: Latest PIOMAS update (June)
« Reply #3660 on: June 11, 2021, 11:57:30 AM »

___________________________________________________
If others want to use a different approach please have a go - the data is there courtesy of Wipneus & Dr. Zhang of the Polar Science Center.

The graph attributed to you shows 2012 sep monthly volume below 4.0.  Wipneus (https://sites.google.com/site/arctischepinguin/home/global-sea-ice  https://sites.google.com/site/arctischepinguin/home/giomas/data/giomas-sumdata.csv.txt?attredirects=0) shows 5.023.

So as long as you aren't expecting the raw data to be the same...  The following graphs have consistent trend lines.

We have a data problem.

Please note the data is "giomas", not PIOMAS?

Giomas is the same idea as PIOMAS, same university group. It is older, has less resolution (expect less precision) yet is has global coverage (includes Southern Hemisphere). It is also less frequently updated, sometimes after a request from me.

G/P trends are comparable , I can agree with that.
Thanks, Wipneus, for the enlightenment.

I had forgotten entirely that GIOMAS existed. I do not think I will use it for Arctic analyses. Any chance of an update? Would be interesting to look at it for the Antarctic data, especially as in the last few years the sea ice there has gone from record highs to record lows and is on the upswing again. Do they produce data by the 5 regions?
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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3661 on: June 19, 2021, 07:35:47 PM »
PIOMAS has updated gridded thickness data up to day 166 (15th of June). Volume calculated from the thickness on that day was 16.8 [1000 km3], which is 6th lowest for that day compared with previous years.

Here is the animation for June so far.

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3662 on: June 19, 2021, 07:38:29 PM »
The updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3663 on: June 19, 2021, 07:39:27 PM »
The updated Fram volume export graph.

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3664 on: June 19, 2021, 07:40:08 PM »
Some people have good use for the updated regional data files:

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz

gerontocrat

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3665 on: June 19, 2021, 08:29:06 PM »
Some people have good use for the updated regional data files:

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz
hullo Wipneus,

Unless I am making a fool of myself, the file is still only to day 151.
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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3666 on: June 21, 2021, 01:01:01 PM »
Some people have good use for the updated regional data files:

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz
hullo Wipneus,

Unless I am making a fool of myself, the file is still only to day 151.

Google complained about lack of rights.  It seems to have fixed its self.

gerontocrat

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3667 on: June 21, 2021, 03:00:20 PM »
Some people have good use for the updated regional data files:

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz
hullo Wipneus,

Unless I am making a fool of myself, the file is still only to day 151.

Google complained about lack of rights.  It seems to have fixed its self.
Thanks Wipneus.
Google has been a pain recently. It blocked access to ftp files a month or two ago but now suddenly I can access some, but only some, of them.
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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3668 on: June 21, 2021, 06:32:56 PM »
So here is the PIOMAS data analysed in the same as I do for JAXA sea ice

PIOMAS  Volume as at 15 Jun 2021  16,840 KM3

- Volume loss from maximum on this date is 5,710 km3, 164 km3, (3%),  less than the 10 year average of 5,875 km3.

- Volume is at position #6 in the satellite record

- Volume is  838 km3 MORE than 2012
- Volume is  1,228 km3 MORE than 2017
- Volume is  138 km3 LESS than 2020
- Volume is  158 km3 LESS than 2010's average
Projections.

Average remaining volume loss (of the last 10 years) would produce a minimum volume in Sept 2021 of 4,680 km3, 1,007 km3 above the 2012 record low minimum volume of 3,673 km3

This minimum would be 8th lowest in the 43 year satellite record.
_________________________________________________
NSIDC sea ice area measurements are a major driver of the PIOMAS model. You can see this in the daily ice volume loss graph PIOMAS - vol-2. For the week June 8 to 14 sea ice area losses were below average. On the 15th sea ice area loss accelerated. The Vol-2 graph reflects this.

From the 5 days since, sea ice area losses have been very much above average. It will be interesting to see how the PIOMAS model deals with this.

___________________________________________________________
N.B. Click on image  for full-size
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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3669 on: June 21, 2021, 08:01:25 PM »
Volume and Thickness - Kara & the CAB

A bit of a contrast here. With the at least partial revovery of ice extent and area in the freezing season 20-21 I expected to see the CAB with hih volume and thickness. As usual, I was wrong. Both volume and thickness of the CAB have been consistently below the 2010's average.

The Kara sea, in a recent science paper was declared as having crossed the Rubicon in that ocean heat gained in the melting season is enough to prevent full ice recovery in the freezing season. It seems that this is not true this year. Volume and thickness are very much above the 2010's average.

ps: The colour scheme in the CAB thickness graph is awful. But I'm not changing it.

click images to enlarge
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VeliAlbertKallio

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3670 on: June 22, 2021, 01:17:01 AM »
Interestingly, Piomas places the thickest ice behind Nunavut where as other models suggest the thickest ice near Alaskan coast on the Beaufort Sea. Cryosat suggested it have been pushed to throat of the Fram Strait - the parking area between the straight and the North Pole. I just keep wondering where is the thickest ice, and where it isn't.

PIOMAS has updated gridded thickness data up to day 166 (15th of June). Volume calculated from the thickness on that day was 16.8 [1000 km3], which is 6th lowest for that day compared with previous years. Here is the animation for June so far.
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gerontocrat

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Re: Latest PIOMAS update (June, mid-monthly update)
« Reply #3671 on: June 23, 2021, 11:39:21 PM »
For those interested in the daily volume minimum (as opposed to the September Monthly Average) attached is the graph from 1979 to the current estimate for 2021 (data to June 15).

The 2021 current estimated volume at minimum is 4.680 thousand km3, some 738 km3 above the long-term linear trend value of 3.942 thousand km3.

However, this could change very quickly, even from the stronger melt that occurred in the week from 15th June to now.
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Wipneus

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Re: Latest PIOMAS update (July)
« Reply #3672 on: July 05, 2021, 09:18:13 AM »
PIOMAS has updated gridded thickness data to the 30th of June (2021, day 181). Volume calculated from thickness on that last day was 12.9 [1000km3]. Compared with previous years that is the fifth lowest value.
Here is the animation for June.

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Re: Latest PIOMAS update (July)
« Reply #3673 on: July 05, 2021, 09:26:11 AM »
Updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (July)
« Reply #3674 on: July 05, 2021, 09:28:40 AM »
Update Fram volume export graph.

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Re: Latest PIOMAS update (July)
« Reply #3675 on: July 05, 2021, 09:31:15 AM »
Thickness map, compared with previous years and their diffs.

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Re: Latest PIOMAS update (July)
« Reply #3677 on: July 05, 2021, 09:40:01 AM »
On request I made a version of the PIOMAS monthly volume graphs, plotted per month with linear trends.
I like it much better than the "old" version with exponential declines, but see for yourself.
Attaching old and new.

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Re: Latest PIOMAS update (July)
« Reply #3678 on: July 05, 2021, 08:30:02 PM »
Thanks, Wipneus, for both the exponential and the linear trend lines.  (I hadn't asked.)  If one added a +/- 2 standard deviation cone to the linear trend, a 'likely' first blue ocean event projects to (per my eye-balling) later this decade.
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Re: Latest PIOMAS update (June)
« Reply #3679 on: July 05, 2021, 09:56:55 PM »
How can anyone believe that there is more ice volume now than in 2017?

Seriously.

The updated volume and volume-anomaly graphs.

oren

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Re: Latest PIOMAS update (July)
« Reply #3680 on: July 05, 2021, 10:47:27 PM »
Early 2017 was highly anomalous. 2016 finished the melting season very near 2012's sea ice area minimum, and the autumn and winter saw extremely slow freezing, with the Chukchi specifically staying partially open into January. It is no wonder PIOMAS gave 2017 as the lowest volume max on record. This provided an advantage for a while despite the rather weak melting season, and I do believe 2017 had a volume lead during winter and spring, but it did not last through the summer.

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Re: Latest PIOMAS update (June)
« Reply #3681 on: July 05, 2021, 10:53:57 PM »
How can anyone believe that there is more ice volume now than in 2017?

Seriously.
That is what the PIOMAS data says - by 711km3 as at 30th June
___________________________________________________
Meanwhile, PIOMAS data in gerontiocrat's standard fomat

PIOMAS  Volume as at 30 Jun 2021  12,864 KM3

- Volume loss from maximum on this date is 9,686 km3, 203 km3, (2%),  more than the 10 year average of 9,483 km3.

- Volume is at position #5 in the satellite record

- Volume is  569 km3 MORE than 2012
- Volume is  711 km3 MORE than 2017
- Volume is  88 km3 MORE than 2020
- Volume is  543 km3 LESS than 2010's average
Projections.

Average remaining volume loss (of the last 10 years) would produce a minimum volume in Sept 2021 of 4,313 km3, 640 km3 above the 2012 record low minimum volume of 3,673 km3.

This minimum would be 5th lowest in the 43 year satellite record.
_______________________________
For most of the seond half of June daily volume losses well above average.
And, of course, the timimg of the big sea ice extent losses in early July means we have to wait a couple of weeks to see how PIOMAS deals with that. (sigh)

___________________________________________________________
N.B. Click on image  for full-size
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Re: Latest PIOMAS update (July)
« Reply #3682 on: July 06, 2021, 05:17:33 PM »
We have monthly averages sea by sea of sea ice volume going back to 1979 courtesy of The Polar Science Center & Wipneus.

So far I have only done graphs for the Total Arctic, The High Arctic, the Peripheral Seas and the CAB, which I attach.

To me of note is...
- the decadal averages show a continuous acceleration in volume loss.
- The total graph shows volume loss since 1979 in winter is lower than in summer.
- The Peripheral Seas have lost at least 25% of their winter ice maximum since 1979, and the summer ice minimum approaches zero (probably what remains is mostly in the Greenland Sea).
- The seven seas of the High Arctic have also lost at least 25% of their winter ice maximum since 1979, and approaching 70% of the summer ice minimum.

- The CAB, the unassailable ice fortress of yesteryear, has lost 25% of its winter ice maximum, and over 50% of its summer ice minimum.

click images to enlarge

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Tor Bejnar

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Re: Latest PIOMAS update (July)
« Reply #3683 on: July 06, 2021, 06:31:18 PM »
2021 CAB ice volume has the largest April to May increase of periods shown in the graph. 

If all that growth is under a meter of ice, that other ice must be colder than usual.  If it's colder, it will requiring warming before it can melt.

If all the growth is in repeatedly opening leads, then it is thin and warm and won't require much heat to melt.

Possibly a mixture of the two, with no net consequences....  :-\
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Re: Latest PIOMAS update (July)
« Reply #3684 on: July 06, 2021, 07:16:25 PM »
The linear fit is better. Immediately after 2012 we didn't realize how anomalous 2012 was. We thought that the rate of volume decline might be accelerating. By now it is clear that the rate of decline is pretty much the same.

One thing to remember is that the percentage of first year ice has increased so the porosity and salinity of the ice, on average, has been increasing over the decades. The melting zone in the Beaufort sea has changed the nature of the ice pack by melting out the old ice.

The ice we have now is not more stable. It is better protected by its location near the pole than old ice that rotated into the Beaufort sea.

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Re: Latest PIOMAS update (June)
« Reply #3685 on: July 16, 2021, 07:38:08 PM »
Hello Wipneus, as usual many thanks for all the outputs of PIOMAS (as well as other data) you provide. I have a question/request - is it possible to generate a chart of export through the FJL/Svalbard gap, similar to the Fram export chart? It appears that lately this export is becoming quite important, due to the increased mobility of the ice in that sector of the CAB.
I notice that the 80N latitude circle between ~27E and ~47E can be defined as the approximate export line, which might make calculations easier.

Hi Oren, I looked at it and the situation does not look that easy as you think. The PIOMAS grid does not follow normal lat/lon lines. While I could draw a straight vertical line (in PIOMAS coordinates) in the Fram, no such line is possible in the FJL/Svalbard gap.

See attached map for the PIOMAS grid, Fram boundary, FJL and Svalbard.


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Re: Latest PIOMAS update (July)
« Reply #3686 on: July 17, 2021, 05:32:09 PM »
Thanks a lot for the response, Wipneus.
Maybe an approximation is possible? Ice that nears the Svalbard-FJL gap is at high risk of melt/export, and quite possibly already meets the Atlantic influence before it crosses that line. So if you were to draw two lines (one horizontal, one vertical) that form a triangle of sorts that protrudes into the CAB, can you calculate the volume that crosses into that region?
Please see attached image in faint red lines.

Aluminium

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Re: Latest PIOMAS update (July)
« Reply #3687 on: July 17, 2021, 06:39:40 PM »
I have an idea.

oren

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Re: Latest PIOMAS update (July)
« Reply #3688 on: July 17, 2021, 07:55:07 PM »
Interesting idea. As some of the exported ice already melts before it crosses the export barrier, due to higher temperature and salinity in the adjacent region, moving the export barrier to the north could also serve to "catch" some of the export that is now undocumented.
In any case, I would move your line a few pixels to the south, starting from the tip of the last tiny island.

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Re: Latest PIOMAS update (July)
« Reply #3689 on: July 17, 2021, 08:21:42 PM »
It seems factible to calculate the fluxes along a PIOMAS “parallel” and then along a PIOMAS “meridian”, just two integrations instead of one, one of them changing the u by the v and the v by -u, or something like that.

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Re: Latest PIOMAS update (July)
« Reply #3690 on: July 17, 2021, 09:02:17 PM »
Perhaps someone should ask Wipneus if
a) he is willing to do it and
b) the practical difficulties involved and his preferred methodology.
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Re: Latest PIOMAS update (July)
« Reply #3691 on: July 17, 2021, 10:14:41 PM »
Perhaps someone should ask Wipneus if
a) he is willing to do it and
b) the practical difficulties involved and his preferred methodology.
I agree! As far as I can see it, nobody here knows the PIOMAS data better than Wipneus. And it is his work.

@Wipneus:
I'd still be curious. If you are willing to do it, I would suggest a side-by-side comparison of standard Fram export, and the line drawn by Aluminium. Firstly because it looks like the simplest of the suggested solutions (no triangles); secondly because of what Oren said. What do you think about the idea?
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

oren

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Re: Latest PIOMAS update (July)
« Reply #3692 on: July 18, 2021, 12:49:07 AM »
Perhaps someone should ask Wipneus if
a) he is willing to do it and
b) the practical difficulties involved and his preferred methodology.
To be clear, I did ask both upthread and in pm to Wipneus. Obviously it's his decision alone.

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Re: Latest PIOMAS update (July)
« Reply #3693 on: July 19, 2021, 02:38:35 PM »
Perhaps someone should ask Wipneus if
a) he is willing to do it and
b) the practical difficulties involved and his preferred methodology.
To be clear, I did ask both upthread and in pm to Wipneus. Obviously it's his decision alone.

Yes, I must be clear about this.
 a) yes it is interesting and I am willing to spend some time on it;
 b) the practical difficulties means it will take significant time that I at this moment do not have. Any implementation will not be possible for some time (couple of months).
About the preferred method: some interesting paths have been proposed, but I would like to go for the "shortest path" (like drawing a straight line on a pixelated display). Once you have handled one corner, the step to "n" corners should be easy.

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Re: Latest PIOMAS update (July)
« Reply #3694 on: July 19, 2021, 02:48:16 PM »
Thanks a lot for the response, Wipneus.
If and when you find the time, I think a straight line (in PIOMAS coordinates) covering both Fram and Barents gap could be the easiest solution and quite useful too, as proposed by Aluminium above, maybe shifted slightly south as seen in the attached (thick red line).

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Re: Latest PIOMAS update (July, mid-monthly update)
« Reply #3695 on: July 19, 2021, 07:54:58 PM »
Meanwhile PIOMAS gridded thickness data had a mid-monthly update up to 15th July (day of year 196). Volume calculated from thickness was  9.47 [1000km3], 6th lowest value or day 196 of all years.

Here is the animation.

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Re: Latest PIOMAS update (July, mid-monthly update)
« Reply #3696 on: July 19, 2021, 07:59:29 PM »
Here are the updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (July, mid-monthly update)
« Reply #3697 on: July 19, 2021, 08:03:52 PM »
Updated Fram volume export graph.

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Re: Latest PIOMAS update (July, mid-monthly update)
« Reply #3698 on: July 19, 2021, 08:05:59 PM »
Some people have good use for the updated regional data files:

daily:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz

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Re: Latest PIOMAS update (August)
« Reply #3699 on: August 04, 2021, 06:51:39 PM »
PIOMAS has updated gridded thickness data to the 31st of July (2021, day 212). Volume calculated from thickness on that last day was  7.06[1000km3]. Compared with previous years that is the sixth lowest value.
Here is the animation for July.