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Author Topic: Latest PIOMAS update (April, mid-monthly update)  (Read 1359153 times)

gerontocrat

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Re: Latest PIOMAS update (January)
« Reply #3550 on: January 05, 2021, 11:43:25 AM »
data from Wipneus / PIOMAS - a bit more

I attach the PIOMAS Volume December Monthly Average graph.
At 11,799 km3, the 2020 December average is 2nd lowest in the satellite record, some 362 km3 less than the linear trend value. The lowest December average was in 2016, at 11,206 km3.

I also attach a table and graph of the 365 day trailing average volume. At the current rate of decline of the trailing average, a new record low average volume is likely in mid-2022, 5 years after the current record low in late August 2017.

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oren

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Re: Latest PIOMAS update (January)
« Reply #3551 on: January 06, 2021, 03:43:20 AM »
Finally, in its last gasp 2020 managed to break away from 2016, though this did not suffice to cross above 2012.
The main region to thank is the Siberian sector. Laptev and Kara have both left record low territory at last. In the Pacific sector one could have a hoped for a higher year-end result, considering the high volume throughout the summer. The CAB is still very low but not as bad as 2016.
Looking at daily record lows, 2020 had a respectable showing, but is still behind 2012, 2019, and 2017. 2010 has finally lost its only daily record and was kicked of of the chart.
Hopefully, early 2021 will see better volume growth than early 2017 had.

My next update will require the annual hell of adding a new line to all charts and fixing colors.
The usual thanks to Wipneus, without whom the regional data would not be available anywhere.

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3552 on: January 20, 2021, 09:32:42 AM »
PIOMAS gridded thickness data was updated to day 15 (15th January). Volume calculated from thickness was 15.56 [1000km3], second lowest for that day of year.

Here is the animation for January so far.

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3553 on: January 20, 2021, 11:18:48 AM »
Updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3554 on: January 20, 2021, 12:07:37 PM »
The updated Fram volume export graph.

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3555 on: January 20, 2021, 12:09:54 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

BornFromTheVoid

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3556 on: January 20, 2021, 12:41:09 PM »
Appreciated as always, Wipneus.

Here's my contribution
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gerontocrat

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3557 on: January 20, 2021, 01:57:47 PM »
Some people have good use for the updated regional data files.
Good use of the data or not here is an analysis as at 15 jan.

PIOMAS  Volume as at 15 Jan 2021  15,557 KM3

- Volume gain from minimum on this date is 11,528 km3, 175 km3, (1%),  less than the 10 year average of 11,703 km3.

- Volume is at position #2 in the satellite record

- Volume is  157 km3 LESS than 2013
- Volume is  986 km3 MORE than 2017
- Volume is  754 km3 LESS than 2020

Projections.

Average remaining volume gain (of the last 10 years) would produce a maximum volume in April 2021 of 21,833 km3, 1,051 km3 above the 2017 record low maximum volume of 20,782 km3.
___________________________________________________________
N.B. Click on image  for full-size
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gerontocrat

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Re: Latest PIOMAS update (January, mid-monthly update)
« Reply #3558 on: January 20, 2021, 06:31:50 PM »
More analysis derived from the PIOMAS data from Wipneus

The January monthly average graph is attached, using actual data to 15 Jan and average volume gain from 10 to 31 Jan giving a monthly average of 15.6 thousand km3. This is 120 km3 less than the trend value - less than half a year ahead of trend. This would be 2nd lowest in the satellite record, 975km3 more than Jan 2017.

It should be noted that the Jan 2017 was 2,200 km3 or 8 years below the linear trend. One way looking at the 2021 Jan average is that over half that 2017 2,200km3 deviation has been clawed back by Jan 2021.

Also attached is a table and graph of the 365 day trailing average volume . It is still 891 km3 above the record low on 31 August 2017, but is currently declining at 2km3 per day, some 2 1/2 times the long-term average. It is certainly possible that a new record low could be reached in 2022, but in 2021? - highly unlikely.
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Re: Latest PIOMAS update (February)
« Reply #3559 on: February 04, 2021, 11:12:25 AM »
PIOMAS gridded thickness data was updated. Volume calculated for the last day (31st Jan) was 17.6 [1000km3], which is the third lowest figure for that day.

Attached is the animation for January.

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Re: Latest PIOMAS update (February)
« Reply #3560 on: February 04, 2021, 12:10:32 PM »
The updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (February)
« Reply #3561 on: February 04, 2021, 12:11:20 PM »
Update Fram volume export graph.

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Re: Latest PIOMAS update (February)
« Reply #3563 on: February 04, 2021, 12:16:26 PM »
Thickness map for January + comparison with previous years + their diff's.

BornFromTheVoid

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Re: Latest PIOMAS update (February)
« Reply #3564 on: February 04, 2021, 01:34:06 PM »
Looks like the Russian Arctic coastline is doing very well, but the CAB has now dropped to lowest on record.
Thanks as always, Wipneus.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gerontocrat

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Re: Latest PIOMAS update (February)
« Reply #3565 on: February 04, 2021, 02:00:17 PM »
Here is a post based on the JAXA analysis format.

PIOMAS  Volume as at 31 Jan 2021  17,634 KM3

- Volume gain from minimum on this date is 13,605 km3, 205 km3, (2%),  more than the 10 year average of 13,400 km3.

- Volume is at position #3 in the satellite record

- Volume is  99 km3 LESS than 2013
- Volume is  1,474 km3 MORE than 2017
- Volume is  649 km3 LESS than 2020

Projections.

Average remaining volume gain (of the last 10 years) would produce a maximum volume in April 2021 of 22,213 km3, 1,431 km3 above the 2017 record low maximum volume of 20,782 km3.
___________________________________________________________
From 10th Jan daily volume change switched from below to above average.
___________________________________________________________
N.B. Click on image  for full-size
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gerontocrat

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Re: Latest PIOMAS update (February)
« Reply #3566 on: February 04, 2021, 09:55:06 PM »
I thought I would give the thickness grapohs an airing** , starting with 3 graphs for the total volume and area for - all seas, the High Arctic and the Peripheral Seas.

They all show thickness low but not lowest. But they give an ratehr nice illustration of the drop in average thickness in the first month or two of the freezing season. This is due to that bottom melting still continues, while sea ice area increases strongly. As thickness = volume divided by area, arithmetic demands that thickness declines until bottom melting reduces and freezing from the top is sufficient.

Note also how thickness keeps rising well into the melting season. Thin ice at the sea ice edges melts quickly but only reduces volume slightly, so the average keeps on rising. Arithmetic rules, OK.
_________________________________________
**I cannot do this for all seas as my NSIDC data has significantly different boundaries for 5 of the 7 High Arctic regions from those defined in the Wipneus PIOMAS data.
______________________________________
click images to enlarge
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gerontocrat

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Re: Latest PIOMAS update (February)
« Reply #3567 on: February 04, 2021, 10:48:42 PM »
It's late, I am tired - one more set of graphs for individual seas. Note that the thickness graphs for individual seas have lots of wobbles - especially when volume is low. One day (maybe) I will try using 5-day PIOMAS trailing average volume to match the NSIDC 5 day trailing average area- it might make a difference.

KARA Thickness recovered quickly despite the very late freeze.

Barents Thickness also shows how late the freeze was in 2020. The year to year variation is very high - Atlantification has its ups and downs.

Greenland Area is high this year, but thickness not.

CAA Thickness very much at 2010's average, but it does show the reduction from the 2000's decadal average.
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3568 on: February 19, 2021, 06:40:00 PM »
PIOMAS gridded thickness data was updated to the 15th of February (day 46 of 2021). Volume calculated from thickness on that day was 19.3 [1000km3], which is the third lowest for that day.

Here is the animation for February sofar.

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3569 on: February 19, 2021, 06:41:05 PM »
The updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3570 on: February 19, 2021, 06:44:27 PM »
Updated Fram volume export graph.

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3571 on: February 19, 2021, 06:45:59 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

gerontocrat

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3572 on: February 20, 2021, 05:44:13 PM »
This one has use for the files.
Life plays tricks - get volume data to the 15th then extent and area data goes bonkers on the 17th.

PIOMAS  Volume as at 15 Feb 2021  19,324 KM3

- Volume gain from minimum on this date is 15,295 km3, 587 km3, (4%),  more than the 10 year average of 14,708 km3.

- Volume is at position #3 in the satellite record

- Volume is  142 km3 LESS than 2013
- Volume is  1,944 km3 MORE than 2017
- Volume is  339 km3 LESS than 2020

Projections.

Average remaining volume gain (of the last 10 years) would produce a maximum volume in April 2021 of 22,595 km3, 1,813 km3 above the 2017 record low maximum volume of 20,782 km3.
______________________________________________________________
In the last 4 weeks daily volume gain is consistently greater than the 10 year average.
___________________________________________________________
N.B. Click on image  for full-size
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3573 on: February 21, 2021, 09:21:22 AM »
A few volume  graphs
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gerontocrat

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3574 on: March 03, 2021, 11:19:52 AM »
I suspect the lack of NSIDC data has consequences
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3575 on: March 03, 2021, 01:40:22 PM »
No "February Update" just yet, but the PSC site seems back to normal now?
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3576 on: March 03, 2021, 03:07:50 PM »
No "February Update" just yet, but the PSC site seems back to normal now?
I still say (and hope i am wrong) that without NSIDC DMSP F18 data there can be no PIOMAS update because...

From http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/
Quote
PIOMAS is a numerical model with components for sea ice and ocean and the capacity for assimilating some kinds of observations. For the ice volume simulations shown here, sea ice concentration information from the NSIDC near-real time product are assimilated into the model to improve ice thickness estimates and SST data from the NCEP/NCAR Reanalysis are assimilated in the ice-free areas.
Follow the link for "NSIDC near-real time product" to https://nsidc.org/data/nise
Near-Real-Time SSM/I-SSMIS EASE-Grid Daily Global Ice Concentration and Snow Extent, Version 5
Quote
This NISE Version 5 product contains DMSP-F18, SSMIS-derived sea ice concentrations and snow extents derived from the Special Sensor Microwave Imager/Sounder (SSMIS) aboard the Defense Meteorological Satellite Program (DMSP) F18 satellite

Parameter(s):   
Spatial Coverage:   N: 90, S: -90, E: 180, W: -180
Platform(s):   DMSP 5D-3/F18
Spatial Resolution:   25 km x 25 km
Sensor(s):   SSMIS

And just to add to the gaiety of nations,  https://nsidc.org/data/nise says

On Wednesday, March 3rd from 9:00 a.m. to 1:00 p.m. (USA Mountain Time), the following data collections may not be available due to planned system maintenance: AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, ICESat-2, MEaSUREs, MODIS, NISE, SMAP, SnowEx, and VIIRS.
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3577 on: March 03, 2021, 03:24:07 PM »
I still say (and hope i am wrong) that without NSIDC DMSP F18 data there can be no PIOMAS update because...

However OSI-SAF have been happily processing F18 data for several days now.

Quote
OSI SAF service message #2225
Sent on Tue, 23/02/2021 - 12:07 UTC

Title : Resuming product Global Sea Ice Concentration (SSMIS) OSI-401-b

Message :

Dear OSI SAF Sea Ice Concentration User,

In regards to our previous message, we came to the following conclusion:

After the interruption in incoming DMSP SSMIS data that took place last Friday, 19th Feb., the input data started to come slowly again since Monday 22nd around 00:27 UTC. However, there were many missing sectors and that led to missing data in the final product.

More importantly, for the SSMIS Ice Concentration product* (OSI-401-b), three sensors are used, namely F-16, F-17 and F-18, we found out that F-16 contains corrupted data, and that led to corrupted data in the final product.

From now on we will be using only F-17 and F-18.
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gerontocrat

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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3578 on: March 03, 2021, 04:12:46 PM »
I still say (and hope i am wrong) that without NSIDC DMSP F18 data there can be no PIOMAS update because...

However OSI-SAF have been happily processing F18 data for several days now.

Quote
OSI SAF service message #2225
Sent on Tue, 23/02/2021 - 12:07 UTC

Title : Resuming product Global Sea Ice Concentration (SSMIS) OSI-401-b

Message :

Dear OSI SAF Sea Ice Concentration User,

In regards to our previous message, we came to the following conclusion:

After the interruption in incoming DMSP SSMIS data that took place last Friday, 19th Feb., the input data started to come slowly again since Monday 22nd around 00:27 UTC. However, there were many missing sectors and that led to missing data in the final product.

More importantly, for the SSMIS Ice Concentration product* (OSI-401-b), three sensors are used, namely F-16, F-17 and F-18, we found out that F-16 contains corrupted data, and that led to corrupted data in the final product.

From now on we will be using only F-17 and F-18.
Which then leads me to ask - if F-17 and F-18 are working OK, how come NSIDC are not producing  the sea ice data files?
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Re: Latest PIOMAS update (February, mid-monthly update)
« Reply #3579 on: March 03, 2021, 05:04:10 PM »
Which then leads me to ask - if F-17 and F-18 are working OK, how come NSIDC are not producing  the sea ice data files?

That remains a mystery!
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Re: Latest PIOMAS update (March)
« Reply #3580 on: March 03, 2021, 06:39:46 PM »
PIOMAS gridded thickness data was updated up to the 28th of February. Volume calculated from thickness was 20.4 [1000km3], third lowest for that day of year.

Here is the animation.

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Re: Latest PIOMAS update (March)
« Reply #3581 on: March 03, 2021, 06:41:27 PM »
Updated volume and volume-anomaly graphs.

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Re: Latest PIOMAS update (March)
« Reply #3582 on: March 03, 2021, 06:45:11 PM »
Updated Fram volume export graph. During some days it was negative (import), also visible in the animation above.

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Re: Latest PIOMAS update (March)
« Reply #3584 on: March 03, 2021, 06:51:13 PM »
The 28 February thickness map, comparison with previous years and their differences.

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Re: Latest PIOMAS update (March)
« Reply #3585 on: March 03, 2021, 07:23:13 PM »
I was a bit surprised reading today's comments.

NSIDC f18 based sea ice concentration data is available except for 20/21 Feb., 19 & 22 Feb data may be partly missing.

NSIDC seems not to trust the data fully as their latest message that I am aware of is this:

https://nsidc.org/arcticseaicenews/2021/02/sea-ice-processing-errors/
https://twitter.com/NSIDC/status/1365358720591405060

Quote
Sea ice processing is currently having problems. Daily Sea Ice Index/Arctic Sea Ice News and Analysis values after February 19 are erroneous. NSIDC is investigating the issue and will correct it as soon as possible.

That was on the 26th, nothing since. But similar issues like the F17 took weeks, so that says not much.

The F17 data is as far as I know not trusted by NSIDC, this old message is still on the site:
http://nsidc.org/the-drift/data-update/nsidc-halts-production-of-the-near-real-time-dmsp-ssmis-daily-polar-gridded-sea-ice-concentrations-f17-data/

My calculated extent and area data are here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_arc_nt_main.txt

regional data file is nsidc_arc_nt_detail.txt in the same directory.

substitute ant for arc for the SH data.

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Re: Latest PIOMAS update (March)
« Reply #3586 on: March 03, 2021, 08:09:00 PM »
Update:
Quote
NSIDC continues to investigate errors in our sea ice processing, and we are upgrading software to address the errors. Daily Sea Ice Index/Arctic Sea Ice News and Analysis values after February 19 are erroneous. We will post new data as soon as the software upgrades are implemented.

https://nsidc.org/arcticseaicenews/2021/03/nsidc-continues-to-investigate-sea-ice-processing-errors/
https://twitter.com/NSIDC/status/1367183249382854656

gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3587 on: March 03, 2021, 09:25:14 PM »
Nice to know I was wrong about NSIDC problems preventing the PIOMAS update, but on the other hand a reminder that we are dependent on three very old satellites that do have problems from time to time.
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Re: Latest PIOMAS update (March)
« Reply #3588 on: March 03, 2021, 10:17:31 PM »
Wipneus while we are at it, vould you please update the regional area/extent charts to include 2021?
Thanks a lot for all the data you enable.

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Re: Latest PIOMAS update (March)
« Reply #3589 on: March 03, 2021, 11:01:23 PM »
      And if not too much bother please add 2020 to the PIOMAS annual minimum charts (at least the straight-line version) at https://sites.google.com/site/arctischepinguin/home/piomas
Thanks!

BornFromTheVoid

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Re: Latest PIOMAS update (March)
« Reply #3590 on: March 04, 2021, 10:26:11 AM »
A few graphs from me
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3591 on: March 04, 2021, 05:16:42 PM »
PIOMAS  Volume as at 28 Feb 2021  20,356 KM3

- Volume gain from minimum on this date is 16,327 km3, 582 km3, (4%),  more than the 10 year average of 15,745 km3.

- Volume is at position #3 in the satellite record

- Volume is  547 km3 LESS than 2013
- Volume is  1,756 km3 MORE than 2017
- Volume is  423 km3 LESS than 2020

Projections.

Average remaining volume gain (of the last 10 years) would produce a maximum volume in April 2021 of 22,590 km3, 1,808 km3 above the 2017 record low maximum volume of 20,782 km3.
__________________________________________
In the second half of Feb volume change mirrored changes in sea ice area - gains falling below average as sea ice area declined and then rsing to above average as sea ice area rapidly increased.
___________________________________________________________
N.B. Click on image  for full-size
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gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3592 on: March 04, 2021, 07:29:41 PM »
PIOMAS - a bit more using data from Wipneus

The Wipneus data includes a file of monthly averages going back to 1979 - including by each sea.
This gives the opportunity to look in greater detail going back before the year 2000 - the limit for daily data by individual seas.

I attach 4 graphs of monthly average data:-
- all Arctic,
- the 7 central seas of the High Arctic,
- the 7 peripheral seas of the Arctic,
- the Central Arctic Basin.

From these graphs you can see
- that volume loss has accelerated decade by decade.
- that volume maximum tends to occurs in Mid-April in the High Arctic, and mid-march in the periphery
- volume variation year by year is much higher in the periphery,
- The Central Arctic Basin volume Feb Average is lowest in the satellite record, just below 2017.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3593 on: March 04, 2021, 07:44:50 PM »
More PIOMAS from Wipneus's data files

I attach the February monthly averages graph. Feb 21 volume, at 19,125 km3, is 3rd lowest in the PIOMAS record, some 440km3 less than in Feb 20, but still 430km3 above the linear trend value  and about 1,750km3 greater than the 2017 record low Feb average.

I also attach the table and graph of 365 day trailing average, that shows steady reduction in this average but still 827km3 above the record low on 31 Aug 2017.

And because I like the graph here is the plume of projected changes in volume from previous years' daily change.
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gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3594 on: March 05, 2021, 05:12:33 PM »
I have started to process Wipneus' data files on NSIDC area and extent. In my universe 29 Feb does not exist so I deleted those days. The Wipneus regional analysis uses a wider boundary than NSIDC for the Central Arctic Basin, which signifcantly reduces the area of the Beaufort, Chukchi, ESS and Laptev seas (see attached last image).

NSIDC also include part of the Sea of Japan in their Okhosk data, while this is shown separately in the Wipneus area and extent data.
Qu: Does the Wipneus volume data in the Regional files for the Okhotsk Sea include or exclude Sea of japan volume?

Using Wipneus defined boundaries for both volume and area data allows a meaningful calculation of thickness over time. As we have monthly regional data of volume back to 1979, and monthly area data tables are relatively simple to construct from daily data, it is possible to graph trends in volume and thickness going back to 1979. The downside is that short-term daily variations are smoothed away. I attach the thickness graph from daily changes to demonstrate (complete with ghastly colour scheme).

I attach graphs for the CAB going back to 1979.

click image to enlarge
« Last Edit: March 05, 2021, 05:55:10 PM by gerontocrat »
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oren

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Re: Latest PIOMAS update (March)
« Reply #3595 on: March 05, 2021, 05:49:31 PM »
These are the regions in the Wipneus volume file:
Ocean Okhot Berng Beauf Chukc ESS   Laptv KaraS Baren GrnLS CAB    CAA   Baffn Hudsn StLaw Land

I believe Wipneus uses the same demarcations for all his processing (using the Cryosphere Today boundaries), so if Sea of Japan is separate for area/extent it should be the same for volume. Perhaps it is included in Ocean. Or I am wrong on the demarcations.

gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3596 on: March 05, 2021, 06:14:54 PM »
These are the regions in the Wipneus volume file:
Ocean Okhot Berng Beauf Chukc ESS   Laptv KaraS Baren GrnLS CAB    CAA   Baffn Hudsn StLaw Land

I believe Wipneus uses the same demarcations for all his processing (using the Cryosphere Today boundaries), so if Sea of Japan is separate for area/extent it should be the same for volume. Perhaps it is included in Ocean. Or I am wrong on the demarcations.
And here are the demarcations in his regional extent and area file
The 14 seas (ignore .e)
cabs.e   esis.e   lapt.e   kara.e   bars.e   grls.e   baff.e   stlb.e   
huds.e   cana.e   beau.e   chuk.e   bers.e   sokh.e   

followed by the bits and pieces
pacf.e         japn.e          alsk.e          atln.e          main.e      balt.e         lake.e
0.028058   0.083518   0.009233   0.002202   0.011146   0.095369   0.268538 million km2 (2 Mar)

I am ignoring the bits and pieces unless otherwise advised.
ps: Some of these bits and pieces are included in NSIDC's total extent and area data although not identified in individual seas data - Meier told me about 200k in winter so presumably does not include "lake.e" (and maybe not the Baltic).

Such things are sent to confuse us amateurs..
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binntho

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Re: Latest PIOMAS update (March)
« Reply #3597 on: March 06, 2021, 05:15:27 AM »
Gero, your "monthly average thickness" graph two posts up is presumably using meters as a unit, rather than thousands of cubic kilometers? 8)
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Wipneus

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Re: Latest PIOMAS update (March)
« Reply #3598 on: March 06, 2021, 09:35:27 AM »
Attached image shows the regional map that I use. I hope it is clear enough what is what. It is a simple extension of the Cryosphere Today map (shown above) with some extra regions defined where they were not in the CT map. They do occasionally have sea ice concentration >0.

So the Japanese Sea is apart from the Okhosk region.

The regions used for the PIOMAS volume files are based on the CT regions. The PIOMAS datamap is smaller than the NSIDC, I suspect the Japanese Sea is not even in it. 

I looked for a date 29 February 2021, but I could not find it.

The NSIDC regions differ somewhat with a smaller CAB, but larger Beaufort and others. Should I use that instead?

gerontocrat

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Re: Latest PIOMAS update (March)
« Reply #3599 on: March 06, 2021, 09:53:05 AM »
Attached image shows the regional map that I use. I hope it is clear enough what is what. It is a simple extension of the Cryosphere Today map (shown above) with some extra regions defined where they were not in the CT map. They do occasionally have sea ice concentration >0.

So the Japanese Sea is apart from the Okhosk region.

The regions used for the PIOMAS volume files are based on the CT regions. The PIOMAS datamap is smaller than the NSIDC, I suspect the Japanese Sea is not even in it. 

I looked for a date 29 February 2021, but I could not find it.

The NSIDC regions differ somewhat with a smaller CAB, but larger Beaufort and others. Should I use that instead?
29 Feb 2021 ? I meant I deleted the lines in your data files for 29 Feb 2020, 2016 etc to give me a standard 365 day year for all years. Makes the little algorithms for producing tables much simpler.

I don't think you should change from your adapted CT boundaries to the NSIDC map boundaries. It would produce inconsistencies with all the analyses done previously. There's an old saying "don't change horses in mid-stream".

Thanks again for all the clarifications (and the data)
"Para a Causa do Povo a Luta Continua!"
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