Support the Arctic Sea Ice Forum and Blog

Author Topic: Latest PIOMAS update (December)  (Read 856189 times)

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2650 on: November 20, 2018, 09:15:21 AM »
Here are the updated volume and volume-anomaly graphs.
« Last Edit: December 04, 2018, 08:15:00 AM by Wipneus »

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (November mid-monthly update)
« Reply #2651 on: November 20, 2018, 09:21:07 AM »
No new Fram export graph, the ice velocity data is missing.

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

Neven

  • Administrator
  • ASIF Royalty
  • *****
  • Posts: 6092
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 244
  • Likes Given: 174
Re: Latest PIOMAS update (November mid-monthly update)
« Reply #2652 on: November 20, 2018, 12:13:11 PM »
Still more or less following 2011.
Compare, compare, compare

gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (November mid-monthly update)
« Reply #2653 on: November 20, 2018, 11:20:32 PM »
Here is the PIOMAS data for mid-Nov from Wipneus  as tables & graphs in the sane format as I use for JAXA extent postings.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Tealight

  • ASIF Citizen
  • Posts: 332
    • View Profile
    • CryosphereComputing
  • Liked: 30
  • Likes Given: 1
Re: Latest PIOMAS update (November mid-monthly update)
« Reply #2654 on: December 03, 2018, 02:12:10 AM »
The November coldness seems have had an impact on the ice. Both thickness and volume increased way above previous years.

Full size images + gif +November netcdf at:
https://sites.google.com/site/cryospherecomputing/amsr2-sea-ice-volume

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2655 on: December 04, 2018, 08:24:05 AM »
PIOMAS data has been updated, both the "official" volume data and graphs as the gridded thickness data.

Volume on 30th November was 11.453 [1000 km3], which is the sixth lowest value for that day.

As I am still downloading the gridded data, we start with the volume and volume-anomaly graphs.

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2656 on: December 04, 2018, 09:14:05 AM »
Here is the animation for November.

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2657 on: December 04, 2018, 09:18:18 AM »
The Fram export graph. During the last few days the export has increased noticeable, which I think is visible in the animation above.

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2659 on: December 04, 2018, 09:28:34 AM »
Thickness map for the 30rd of November, compared with recent years and their diff's.

binntho

  • ASIF Citizen
  • Posts: 267
    • View Profile
  • Liked: 46
  • Likes Given: 27
Re: Latest PIOMAS update (December)
« Reply #2660 on: December 04, 2018, 09:43:19 AM »
The Atlantic front seems way off by several hundreds of thousands of square km. North of Svalbard, at the northern end of Novaya Zemlya towards Franz Josef Land and in the southernmost part of the Kara sea.

oren

  • ASIF Governor
  • Posts: 2975
    • View Profile
  • Liked: 320
  • Likes Given: 596
Re: Latest PIOMAS update (December)
« Reply #2661 on: December 04, 2018, 11:28:43 AM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (December)
« Reply #2662 on: December 04, 2018, 12:15:11 PM »
The Fram export graph. During the last few days the export has increased noticeable, which I think is visible in the animation above.

And here is the Wipneus Fram Strait export graph alongside the Greenland Ice Area (NSIDC 5-day trailing average)
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

binntho

  • ASIF Citizen
  • Posts: 267
    • View Profile
  • Liked: 46
  • Likes Given: 27
Re: Latest PIOMAS update (December)
« Reply #2663 on: December 04, 2018, 12:16:54 PM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

Well this version from NSIDC certainly has lower accuracy, but is still much closer to the Bremen map than to the PIOMAS map.


gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (November mid-monthly update)
« Reply #2664 on: December 04, 2018, 01:38:14 PM »
Here is the PIOMAS data for End-Nov from Wipneus  as tables & graphs in the sane format as I use for JAXA extent postings. A lot of days with above average volume gain in November.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Niall Dollard

  • ASIF Citizen
  • Posts: 293
    • View Profile
  • Liked: 32
  • Likes Given: 9
Re: Latest PIOMAS update (December)
« Reply #2665 on: December 04, 2018, 05:25:07 PM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

I agree with Binntho. No gridded cells could explain that difference.

But in fairness, the PIOMAS is a better effort than the AMSR volume chart posted earlier by Tealight.

Look at the two areas circled in black. Parts of Area A in the Laptev were still not fully ice covered in early November and now it is supposed to be nearing 150cm thick ! PIOMAS puts the same area in the 75cm to 1m bin. Which is probably even a little generous.

Meanwhile Area B shows a river of blue going right up the centre of the Arctic Basin. That's less than 50cm thick. Clearly incorrect. 
« Last Edit: December 04, 2018, 05:31:38 PM by Niall Dollard »

Juan C. García

  • ASIF Middle Class
  • Posts: 887
    • View Profile
  • Liked: 153
  • Likes Given: 223
Re: Latest PIOMAS update (November)
« Reply #2666 on: December 04, 2018, 05:44:14 PM »
Same comment than last month:

Focusing on what has happened…

I started contact with Neven in May or June 2012 and I was shocked with the ASI drop on August, after the Great Arctic Cyclone. I was also impressed by the 2012 PIOMAS Volume graph made by Wipneus. So, when on the first months of 2013 appeared cracks on the ASI, well, several of us were concern of what could happen that year. Finally, 2013 was a good year for the ice and 2014 was even better. It had passed 6 years since 2012 and the collapse has not happened.

Or it has happened?  :o

On extent, the ASI has not even able to break the 2007 record, not to mention the 2012 record. So, there are some people saying that 2012 is an outlier and even 2007 will be difficult to break. But I don’t like extent! Yes, it is important to measure the effect of the Arctic Ocean albedo. But to measure the ASI drop, I am convinced that we should use volume, even if it is harder to measure than extent.

So, what do I see on volume?

First, [September] volume on 2007 has been broken several times. On volume, 2007 is the ninth lowest on record! And even that September 2012 is still the lowest, the difference between 2012 with 2010-2011 and 2016-17 is not that big.

But on the other hand, while 2012 has not been broken, the decadal average show us that we
have a very different Arctic. By example, look at Aug-Oct average on a decadal basis.  The 1990-99 average of 93.6% changed to 68.5% on 2000-09 and to 39.5% on 2010-18.

So, do we need a catastrophe to prove a catastrophe? From my point of view, the catastrophe has already happened. The [Aug-Oct] 39.5% ice that we have on 2010-18, versus the 1979-2000 baseline, is climate change, not just one year, not weather change.
« Last Edit: December 04, 2018, 05:50:18 PM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (December)
« Reply #2667 on: December 04, 2018, 05:55:48 PM »
Herewith a graph of avearge arctic sea ice thickness month by month 19179 to 2018 (PIOMAS volume & NSIDC Monthly Average Extent & Area data)
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

bbr2314

  • ASIF Upper Class
  • Posts: 1234
    • View Profile
  • Liked: 70
  • Likes Given: 13
Re: Latest PIOMAS update (November)
« Reply #2668 on: December 04, 2018, 07:30:28 PM »
Neven, please delete if this is not relevant, however I do believe this is relevant!

<Sorry, PIOMAS data has just been updated, not the place to talk about snow; N.>
« Last Edit: December 04, 2018, 11:09:03 PM by Neven »

gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (December)
« Reply #2669 on: December 04, 2018, 07:36:00 PM »
bbr,
Are you ever going to give links to the data you insert/attach?

There are many people who come to this forum to expand their knowledge not just from our words of wisdom but also by following the links most people provide.

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

bbr2314

  • ASIF Upper Class
  • Posts: 1234
    • View Profile
  • Liked: 70
  • Likes Given: 13
Re: Latest PIOMAS update (December)
« Reply #2670 on: December 04, 2018, 07:45:44 PM »
bbr,
Are you ever going to give links to the data you insert/attach?

There are many people who come to this forum to expand their knowledge not just from our words of wisdom but also by following the links most people provide.
I apologize!

https://climate.rutgers.edu/snowcover/index.php


gerontocrat

  • ASIF Governor
  • Posts: 3653
    • View Profile
  • Liked: 362
  • Likes Given: 7
Re: Latest PIOMAS update (December)
« Reply #2671 on: December 04, 2018, 08:54:38 PM »
bbr,
Are you ever going to give links to the data you insert/attach?

There are many people who come to this forum to expand their knowledge not just from our words of wisdom but also by following the links most people provide.
I apologize!

https://climate.rutgers.edu/snowcover/index.php
Looking down his nose over his half-moon glasses like Judge Jeffrys on a bad day, he said :-

"by your actions ye shall be judged"

(perhaps Neven should think about the following when considering forum decorum rules)
Quote
____________________________________________________________________
The Bloody Assizes were a series of trials started at Winchester on 25 August 1685 in the aftermath of the Battle of Sedgemoor, which ended the Monmouth Rebellion in England.

There were five judges – Sir William Montague (Lord Chief Baron of the Exchequer),[1] Sir Robert Wright,[1] Sir Francis Wythens (Justice of the King's Bench),[1] Sir Creswell Levinz (Justice of the Common Pleas)[1] and Sir Henry Pollexfen, led by Lord Chief Justice George Jeffreys.

Over 1,000 rebels were in prison awaiting the trials, which started in Winchester on 26 August.[1] The first notable trial was that of an elderly gentlewoman named Dame Alice Lyle.[2] The jury reluctantly found her guilty, and, the law recognising no distinction between principals and accessories in treason, she was sentenced to be burned. This was commuted to beheading, with the sentence being carried out in Winchester market-place on 2 September 1685.[1]

From Winchester the court proceeded through the West Country to Salisbury, Dorchester and on to Taunton, before finishing up at Wells on 23 September. More than 1,400 prisoners were dealt with and although most were sentenced to death, fewer than 300 were hanged or hanged, drawn and quartered.
________________________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Richard Rathbone

  • ASIF Citizen
  • Posts: 460
    • View Profile
  • Liked: 11
  • Likes Given: 6
Re: Latest PIOMAS update (December)
« Reply #2672 on: December 04, 2018, 10:39:08 PM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

Well this version from NSIDC certainly has lower accuracy, but is still much closer to the Bremen map than to the PIOMAS map.

Unless Wipneus has done some processing to trim the PIOMAS map back to match a 15% extent contour, which I don't think he has, you aren't comparing like contours.

Niall Dollard

  • ASIF Citizen
  • Posts: 293
    • View Profile
  • Liked: 32
  • Likes Given: 9
Re: Latest PIOMAS update (December)
« Reply #2673 on: December 05, 2018, 12:25:22 AM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

Well this version from NSIDC certainly has lower accuracy, but is still much closer to the Bremen map than to the PIOMAS map.

Unless Wipneus has done some processing to trim the PIOMAS map back to match a 15% extent contour, which I don't think he has, you aren't comparing like contours.

There is also a large lump of ice showing on the Piomas chart just to the west of Cape Farewell.that doesnt really exist. Shows up also on the animations.

uniquorn

  • ASIF Middle Class
  • Posts: 537
    • View Profile
  • Liked: 222
  • Likes Given: 35
Re: Latest PIOMAS update (December)
« Reply #2674 on: December 05, 2018, 12:28:06 AM »
<snippage>
But in fairness, the PIOMAS is a better effort than the AMSR volume chart posted earlier by Tealight.
Accurate feedback. Replied here to keep Neven happy ;)
https://forum.arctic-sea-ice.net/index.php/topic,2268.msg183195.html#msg183195

binntho

  • ASIF Citizen
  • Posts: 267
    • View Profile
  • Liked: 46
  • Likes Given: 27
Re: Latest PIOMAS update (December)
« Reply #2675 on: December 05, 2018, 07:05:03 AM »
binntho, I doubt if it explains everything, but for a more valid comparison you need to compare PIOMAS to  NSIDC extent, which has much larger grid cells and lower accuracy.

Well this version from NSIDC certainly has lower accuracy, but is still much closer to the Bremen map than to the PIOMAS map.

Unless Wipneus has done some processing to trim the PIOMAS map back to match a 15% extent contour, which I don't think he has, you aren't comparing like contours.

Well, I've no idea what that means. I guess the whole point of my posting was to point out that the two (now three) maps did not show "like contours" and that the PIOMAS map was showing several hundreds of thousands of km2 that simply arent' there according to the extent maps.

Not that it makes that much difference to the total volume, the "extra" ice is very thin and would perhaps inflate the total by 10 km3. But I'd still like an explanation. Is the area between e.g. Svalbard and the ice-edge 200km away covered in small but thick floes that when averaged out would cover the whole area by say 20 cm of ice, but are at the same time to small to register on the extent maps? Does the same apply to the other "extras"?

oren

  • ASIF Governor
  • Posts: 2975
    • View Profile
  • Liked: 320
  • Likes Given: 596
Re: Latest PIOMAS update (December)
« Reply #2676 on: December 05, 2018, 07:20:35 AM »
Well, I've no idea what that means. I guess the whole point of my posting was to point out that the two (now three) maps did not show "like contours" and that the PIOMAS map was showing several hundreds of thousands of km2 that simply arent' there according to the extent maps.

Not that it makes that much difference to the total volume, the "extra" ice is very thin and would perhaps inflate the total by 10 km3. But I'd still like an explanation. Is the area between e.g. Svalbard and the ice-edge 200km away covered in small but thick floes that when averaged out would cover the whole area by say 20 cm of ice, but are at the same time to small to register on the extent maps? Does the same apply to the other "extras"?
I'm intrigued as well. I guess only Wipneus is qualified enough to explain this discrepancy. As far as I know PIOMAS corrects itself using NSIDC concentration data, and I seem to recall it also cuts off at the 15% threshold, but I could be wrong.

Wipneus

  • ASIF Governor
  • Posts: 3845
    • View Profile
    • Arctische Pinguin
  • Liked: 219
  • Likes Given: 0
Re: Latest PIOMAS update (December)
« Reply #2677 on: December 05, 2018, 03:17:32 PM »
I'm intrigued as well. I guess only Wipneus is qualified enough to explain this discrepancy. As far as I know PIOMAS corrects itself using NSIDC concentration data, and I seem to recall it also cuts off at the 15% threshold, but I could be wrong.

Not much help I am afraid. The assimilation used in PIOMAS is described here:
https://doi.org/10.1175/JTECH1871.1

The assimilation of sea ice concentration (from NSIDC) does not mean it is instantly copied into the model, it is more "nudged" to the measured values. Smaller absolute values of concentration are nudged less than larger values.

The influence on volume, probably the most important output of PIOMAS, is likely small. My favorite glitch is the ice on the SW coast of Greenland, sometimes present when temperatures are well above zero.

And no, there are no 15% cut-offs. Not in my graphs, not in those of the PSC (to the best of my knowledge).

binntho

  • ASIF Citizen
  • Posts: 267
    • View Profile
  • Liked: 46
  • Likes Given: 27
Re: Latest PIOMAS update (December)
« Reply #2678 on: December 05, 2018, 03:26:11 PM »
I'm intrigued as well. I guess only Wipneus is qualified enough to explain this discrepancy. As far as I know PIOMAS corrects itself using NSIDC concentration data, and I seem to recall it also cuts off at the 15% threshold, but I could be wrong.

Not much help I am afraid. The assimilation used in PIOMAS is described here:
https://doi.org/10.1175/JTECH1871.1

The assimilation of sea ice concentration (from NSIDC) does not mean it is instantly copied into the model, it is more "nudged" to the measured values. Smaller absolute values of concentration are nudged less than larger values.

The influence on volume, probably the most important output of PIOMAS, is likely small. My favorite glitch is the ice on the SW coast of Greenland, sometimes present when temperatures are well above zero.

And no, there are no 15% cut-offs. Not in my graphs, not in those of the PSC (to the best of my knowledge).

I've got a nagging feeling that I've asked this same question before, and gotten answers as well, but anyway thanks for the answer (again) Wipneus and keep up the good work! And I agree, it doesn't really make any significant difference to the total.

Note to self: Don't ask the same silly questions every few months!

Tor Bejnar

  • ASIF Upper Class
  • Posts: 2160
    • View Profile
  • Liked: 84
  • Likes Given: 24
Re: Latest PIOMAS update (December)
« Reply #2679 on: December 05, 2018, 06:05:37 PM »
Further to Binntho's observation of different products' ice edge, here is a PolarView location map (highlighted yellow box with yellow ice edge) and the imaged area (from 2018-12-04-T17:07:13) with my interpretation written in. On the scale of the location map, the ice edge appears to be pretty exact, and I presume this 'neatness' extends across the Atlantic front (which PolarView doesn't fully cover).  With increased scale, the edge gets fuzzier, of course.
Arctic ice is healthy for children and other living things.

Stephan

  • ASIF Citizen
  • Posts: 196
    • View Profile
  • Liked: 29
  • Likes Given: 24
Re: Latest PIOMAS update (December)
« Reply #2680 on: December 06, 2018, 11:00:25 PM »
I just did some big data treatment on extent, volume and thickness [Dicke], divided into 8 packs, each of them including five years, to look for the long-term trends on extent, volume and thickness of Arctic sea ice. To do this I calculated the average of 1979 to present for every month and averaged the deviations for each month ("Abw." in the graph) for each of the five-year-packs of these three measures.
Whereas extent seems to decrease more or less constantly in each five-year period, volume doesn't do that in the same fashion, thus thickness (calculated from division of volume by extent) also follows a more step-wise decrease than a "smoothy" one. For a better visualisation I used a second (right) y-axis for the deviation of volume.

See attached graph.

Neven

  • Administrator
  • ASIF Royalty
  • *****
  • Posts: 6092
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 244
  • Likes Given: 174
Re: Latest PIOMAS update (December)
« Reply #2681 on: December 07, 2018, 12:07:49 AM »
I've just posted PIOMAS December 2018 on the ASIB.
Compare, compare, compare