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Author Topic: Latest PIOMAS update (April)  (Read 413854 times)

seaicesailor

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Re: Latest PIOMAS update (September)
« Reply #1100 on: September 05, 2016, 09:09:52 AM »
Hi folks,

A few points on PIOMAS:
  • it's silly to compare PIOMAS and AMSR2 charts. PIOMAS is based on NSIDC data (you know, the 25km res. data?). It's produced from the same source as the "blue marble" SIC chart from Aug 25, 2016 attached below
  • PIOMAS claims +/- 1 M km^3 accuracy. They are primarily concerned with representing the trend reliably, not the varagies of seasonal wx
  • if you REALLY want some insight into current volume, you should be looking at SMOS thickness data. When sea ice is <50 cm thick, SMOS is quite accurate, it's not a model (it's DATA), it's released daily, and there's lot's of <50 cm thick sea ice out there ATM.
Have fun storming the Castle, boys (and girls)!

Cheers,
Lodger
Nice
It's not so much comparing 3D data to 2D data but a reality check. If PIOMAS shows ice where visible images show almost open ocean, well...
Only saying hey it may be a bit on the high side because of this. Within its range of validity overall? Most probably.
If the concern is only on longe range trends why publishing daily results each month? Which is cool btw
Can I ask where can you get the historical NSIDC map?

Edit. Latest SMOS map I found is April 2016
« Last Edit: September 05, 2016, 09:18:04 AM by seaicesailor »

Artful Dodger

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Re: Latest PIOMAS update (September)
« Reply #1101 on: September 05, 2016, 12:10:27 PM »
Lodger:

...I think you meant "Vagaries".

Cheers,

Bud

Yeah Buddy, I mean a lot of things in retropect... :D

To paraphrase Rev. Spooner, 'if you throw enough shit against the wall some of it will stink'

Cheers!
Lodger
Cheers!
Lodger

Jim Hunt

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Re: Latest PIOMAS update (September)
« Reply #1102 on: September 05, 2016, 04:37:52 PM »
if you REALLY want some insight into current volume, you should be looking at SMOS thickness data.


But much like CryoSat 2, SMOS doesn't work in summer? The most recent data I can see is from April 16th:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#SMOS
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

OSweetMrMath

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Re: Latest PIOMAS update (September)
« Reply #1103 on: September 07, 2016, 07:43:57 PM »
My updated anomaly (or residual) graph is below. As always, this is computed against the long term trend, so if the anomaly value is the same on two different years, that implies a lower volume in the most recent year. All years are plotted, 2010-2015 are colored sequentially red through purple, and 2016 is the thick black line. After the anomaly rose in July, it fell again in August, corresponding to the quite low current ice volume.


Michael

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Re: Latest PIOMAS update (September)
« Reply #1104 on: September 23, 2016, 02:42:02 PM »
The PIOMAS gridded data have been partially updatedup to 12 Sep 2016. Below are unofficial figures for Volume (103 km3) and Average Thickness (m) derived from giceday data. These figures should be regarded as provisional and will probably be revised upwards in the official figures.
                    Day    Volume     Avg Thickness
31-Aug-16 244 4.62641.0962
01-Sep-16 245 4.56931.1005
02-Sep-16 246 4.51171.1011
03-Sep-16 247 4.47031.0955
04-Sep-16 248 4.4441.0938
05-Sep-16 249 4.41131.0897
06-Sep-16 250 4.38821.0918
07-Sep-16 251 4.39211.0914
08-Sep-16 252 4.39981.0934
09-Sep-16 253 4.40581.0944
10-Sep-16 254 4.42511.0956
11-Sep-16 255 4.44821.0972
12-Sep-16 256 4.47221.0957
« Last Edit: September 25, 2016, 05:12:53 PM by Michael »

slow wing

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Re: Latest PIOMAS update (September)
« Reply #1105 on: September 25, 2016, 02:53:57 AM »
Thank you Michael, appreciated!

Tigertown

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Re: Latest PIOMAS update (September)
« Reply #1106 on: September 25, 2016, 04:04:48 AM »
Correct me if I'm wrong, but don't these numbers really tell a better story of how bad this melt season was;better than extent and area have told us, I mean?

crandles

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Re: Latest PIOMAS update (September)
« Reply #1107 on: September 25, 2016, 02:10:34 PM »
So looking like 3rd lowest:

Following mixes gridded data versus daily data - hopefully not much different.

2012 261   3.673
2011 253   4.302
2016 6Sept  4.388
2010 251   4.630

2nd lowest on daily extent, perhaps 3rd lowest or higher on Sept average extent, 3rd lowest on daily volume. Seems like a similar story regardless of metric this year.

jdallen

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Re: Latest PIOMAS update (September)
« Reply #1108 on: September 25, 2016, 08:39:42 PM »
So looking like 3rd lowest:

<snippage>

2nd lowest on daily extent, perhaps 3rd lowest or higher on Sept average extent, 3rd lowest on daily volume. Seems like a similar story regardless of metric this year.
Based on previous discussion of PIOMAS, and the very different mechanical behavior of the ice this season, I suspect this number is off on the high side; possibly enough to put it into the same ball park as 2012.

However, that is just a technical quibble.  Being published as a statistical tie with 2011 is still unhappy news, and portends badly for the future.
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Tealight

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Re: Latest PIOMAS update (September)
« Reply #1109 on: September 25, 2016, 11:49:07 PM »
Based on previous discussion of PIOMAS, and the very different mechanical behavior of the ice this season, I suspect this number is off on the high side; possibly enough to put it into the same ball park as 2012.

However, that is just a technical quibble.  Being published as a statistical tie with 2011 is still unhappy news, and portends badly for the future.

In my "forecast model volume calculations" 2016 is in 2nd place. All values are higher than in PIOMAS though. I don't claim to have a better model, but as you said PIOMAS tends to overestimate volume in areas with low ice concentration which 2016 has plenty of. Second place is therfore highly likely.

2012   3.869
2016   4.477
2011   4.653
2010   5.190
2007   5.284


Michael

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Re: Latest PIOMAS update (September)
« Reply #1110 on: October 03, 2016, 11:47:56 AM »
PIOMAS have released the September gridded data.

Updated figures for PIOMAS volume derived from hiday gridded data.

    Day    Volume    AVG Thickness
31-Aug-16    244    4.638    1.1006
01-Sep-16    245    4.581    1.1054
02-Sep-16    246    4.524    1.1036
03-Sep-16    247    4.483    1.0991
04-Sep-16    248    4.457    1.0957
05-Sep-16    249    4.424    1.0909
06-Sep-16    250    4.401    1.0949
07-Sep-16    251    4.404    1.0944
08-Sep-16    252    4.412    1.0955
09-Sep-16    253    4.418    1.0977
10-Sep-16    254    4.436    1.0996
11-Sep-16    255    4.459    1.1011
12-Sep-16    256    4.484    1.1021
(hiday.H2016)

September monthly Volume :  4.529 (heff.H2016)

Wipneus

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Re: Latest PIOMAS update (October)
« Reply #1111 on: October 03, 2016, 05:25:17 PM »
Gridded thickness data is available at the usual place. Here is an animated thickness of the month.

Wipneus

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Re: Latest PIOMAS update (October)
« Reply #1112 on: October 03, 2016, 07:01:10 PM »
September thickness 2006 to present and differences with 2016.

Click for bigger pictures.

Neven

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Re: Latest PIOMAS update (October)
« Reply #1113 on: October 03, 2016, 10:56:14 PM »
Thanks, Wipneus. The comparison is interesting. It shows the big difference with 2011 and 2012 may very well get transported to the Atlantic over the winter.
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Wipneus

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Re: Latest PIOMAS update (October)
« Reply #1114 on: October 05, 2016, 08:36:58 AM »
PIOMAS data is now in, both the official daily volume and the gridded thickness data.

For the volume data I updated my graphics, see the top post

Also the graphs that depend on the September minimum, so they change only once every year, are updated. I have attached them to this post. The different linear and non-linear fits have changed little. Exponential fit reached zero 9 months later, linear fit 6 months earlier.

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1115 on: October 05, 2016, 02:39:30 PM »
Thanks, wipneus
The animations below enlarge the map panels provided above, rotate them into NSIDC/WorldView/AMSR2 configuration, and bring them to the same scale ...

Blizzard92

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Re: Latest PIOMAS update (October)
« Reply #1116 on: October 11, 2016, 05:12:28 PM »
Just tweaking around with some figures... masked out September PIOMAS SIT <1.5 meters over times series (via... http://sites.uci.edu/zlabe/arctic-sea-ice-volumethickness/)
 
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Juan C. García

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Re: Latest PIOMAS update (October)
« Reply #1117 on: October 11, 2016, 06:05:01 PM »
Just tweaking around with some figures... masked out September PIOMAS SIT <1.5 meters over times series

Great view of what is happening with the thicker ice!
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

oren

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Re: Latest PIOMAS update (October)
« Reply #1118 on: October 11, 2016, 07:37:42 PM »
Just tweaking around with some figures... masked out September PIOMAS SIT <1.5 meters over times series
Shocking when viewed like this.

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1119 on: October 11, 2016, 11:02:18 PM »
September PIOMAS SIT <1.5 meters
Awesome animation, very effective palette and background plus a generous scale (provided in the download). Miracle that it ran on this forum as 1800 x 1200 when the limit is 700 x 700 (perhaps all the black did little to file size).

We are trying to post stuff here as 'Greenland down' (EPSG:3413) to facilitate overlays with WorldView, AMSR2, nullschool, hycom, buoy locations etc. The scale on the Piomas seems to match AMSR2 sea ice concentratioon, Sept 15th shown, after a 45º rotation and an enlargement by 150.00%, if so a nice touch.

It's clear we are about to rappel right off the end of the rope, not realizing that that dangling icicle (thin ice) is providing a false sense of security extension.

Seems like the Lincoln Sea is not right in 2016 -- that should have some of the thickest ice of all. It appears palette wandered off to a straight black R,G,B = 0,0,0 that cannot be distinguished from background black (no ice). This affected other years as well.

i'm really skeptical though that the ice is anywhere near 8 m thick in the Lincoln Sea. That needs to be reconciled with multi-year mooring data in the Fram (and also Nares) that measured the thicknesses of ice floes passing overhead. These could not plausibly have changed much in thickness after a few days of passage.
« Last Edit: October 12, 2016, 12:18:45 AM by A-Team »

Blizzard92

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Re: Latest PIOMAS update (October)
« Reply #1120 on: October 12, 2016, 05:07:10 AM »
Very neat modification A-Team! Very eye-opening seeing the cumulative changing spatial extent also.

Here's another PIOMAS visualization of SIV... although I need to update it as this animation is for August(s). (available via http://sites.uci.edu/zlabe/arctic-sea-ice-figures/)

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Jim Hunt

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Re: Latest PIOMAS update (October)
« Reply #1121 on: October 12, 2016, 11:46:02 AM »
Seems like the Lincoln Sea is not right in 2016 -- that should have some of the thickest ice of all. It appears palette wandered off to a straight black R,G,B = 0,0,0 that cannot be distinguished from background black (no ice).

According to Wipneus' daily gridded PIOMAS volume thickness "the thickest ice of all" had moved north by September 30th, leaving <1.5 meter thick ice in its wake. See also SMOS from September 28th & an ASCAT animation:
« Last Edit: October 12, 2016, 04:49:51 PM by Jim Hunt »
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A-Team

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Re: Latest PIOMAS update (October)
« Reply #1122 on: October 12, 2016, 03:35:59 PM »
the thickest ice of all had moved north by September 30th, leaving <1.5 meter thick ice in its wake

Very curious. Where did the this new (thin) ice come from, newly frozen? Not really seeing bulk  movement confirmation out of the Lincoln Sea on AMSR2 during this time frame. Export through Nares and Fram were fairly minimal this season.

The other area where I am really skeptical of Piomas is around Kaffeklubben Island, off extreme northern Greenland and six even smaller rocks even farther north. (The island was discovered by Peary in 1900; Danish researcher Lauge Koch first landed and named after the coffee club in the Mineralogical Museum in Copenhagen in 1931.)

Espen and I looked into that in depth a while back on one of the Greenland forums when a rare 15 m Landsat-8 surfaced, LC80372452013137LGN01. It seems adventurers who have walked up there report ankle-deep water over rock, minimal ice build-up. Am recalling that Piomas shows super thick ice there. Ice of any thickness going out the Fram must go up and around this area or shoal out. A detailed map is posted at http://forum.arctic-sea-ice.net/index.php/topic,1474.msg69693.html#msg69693

The second image squeezes all 38 years of ice thicknesses onto a single 700 pixel image for easier comparison. The third looks at the crossed palette differences (inset), 300 distinct colors from 24 bins which is too complex for interpreting year pair interactions. Gif can only hold 256 colors.

It would be great to have the Piomas ice thickness classes scored for total area within each year (4th image), a process that would benefit from automation with this many bins and this many years.
« Last Edit: October 12, 2016, 10:39:26 PM by A-Team »

oren

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Re: Latest PIOMAS update (October)
« Reply #1123 on: October 13, 2016, 08:39:18 AM »
At the end of the melt season the ice north of the NE corner of Greenland started cracking and moving, turning the corner towards the Fram. As PIOMAS gives an average, with all these spaces between the thick floes could this explain why it shows low thickness in that area?

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1124 on: October 15, 2016, 01:39:38 PM »
the ice north of the NE corner of Greenland started cracking  As PIOMAS gives an average, with all these spaces between the thick floes could this explain why it shows low thickness in that area?
Yes, that could the explanation for areas with large leads. The reason Piomas is always shown as a postage stamp is because both its resolution and accuracy are so-so. For the Lincoln Sea, it does not offer many pixels of coverage. Its bizarre choice of a coordinate system centered in Greenland surfaces in a differencing bias artifact (fig 1 below from #1115 differencing, concentric circles in polar stereographic coords).

In this case Piomas was just plain wrong in the Lincoln Sea, which while minor in area is important to old and thick refugium ice. While some dramatic leads opened up in Sept 2016, these were unremarkable in historic context -- it happens a half dozen times each year and so far has portended little. Maybe some day, opening leads will be the first sign of a total blowout through the Fram.

Hycom has it right -- the ice has been 5-6 m thick there the last 30 days, as it has been for decades. There is no way to average in 10% open leads with 90% 5 m ice to get below 1.5 m as shown in Bliz92's Piomas image. https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif

Now Hycom has some issues of its own. Its palette appears to use 'black' for its heavy-handed text, coordinate grid, ice/land boundary, ice near 1.4 m thick, and ice 5 m thick. Each color in a map is supposed to have a unique meaning so 5 uses of 'black' is a total cartographic no-no.

But in fact the too-dark bin colors are not pure black: the thickest bin is RGB = 25 0 0 and the 1.4 m bin is a peculiar blue, RGB = 2 32 57. These two colors need to be lightened to fall within the human eye color gamut (see below, colorbrewer2.org)

Hycom animations uses 100 color bins to display ice thickness classes between zero and five meters, ie 0.05 m distinctions in thickness. That's already questionable in view of its inherent ground accuracy which would be lucky to get within 20% of true floe thicknesses. Twenty color bins would have been plenty (0.25 m increments); 100 bins is for downstream smoothing aesthetics.

However the Hycom map does not use its palette colors in its ice thickness map to any extent. The image below shows the residual 86 colors remaining after each of the palette colors is replaced by magenta. This means users cannot click on a map pixel itself to look up its thickness, the error is coloring the data grid (which isn't provided) instead of coloring the map.

AMSR2 UHH maps of sea ice concentration prove the Hycom map error is gratuitous -- every pixel on a AMSR2 map corresponds uniquely to a color on the concentration key, as it should. AMSR2 uses the Arctic standard projection put forth by NSIDC, as it should; the Hycom map can be rotated into this from anglocentric meridional view but only with further degradation of colors.

In the old days of printed journals and CMYK dithering, it didn't matter. For the last 20 years though, we've used the internet for color. All imagery software has provided a color selecting tool (called 'magic wand' in photoshop) that selects all pixels of the same color as a clicked pixel (or to within a user-set radius of that pixel in RGB color space).

A Hycom frame has 188 colors in total, well within the 255 limit of gif format. It does not dither text (anti-aliasing) like so many products we see, text lifts off when pure black RGB =000 is substituted. Open ocean is represented by a pure gray RGB 254 254 254; lakes are a single tan. The palette also has a bounding box of one pure black pixel.

Importantly for complex areas like the Lincoln Sea, the boundary between land and ocean is also pure black. That means it can be replaced by land brown to reduce confusion between boundary and dark thickness bin pixels.

Thus the template (receiving base map) is done correctly -- except for the fact that two of the color bins are the wrong size, 8 pixels high instead of 6 like the other ninety eight bins. (It also  lacks tick marks on the side associated with scale depth number; color bins are actually depth ranges.) This is a very strange error suggesting unsystematic construction of the color key.

The colors are a total hack, looking at them as HSV or RGB  progressions or in human eye gamut (below). It is better to construct palettes numerically in a spreadsheet or using precision gradient tricks, as described in previous posts or with visual discrimination ramping. It is easy to crank out palettes by the billions; this one was likely furnished anonymously within the software as a menu option.

The fourth image shows a technical analysis of the Hycom sea ice thickness display. This proves Hycom is showing the very thickest ice in the Lincoln Sea -- not a land boundary or the too dark blue but something above yellow and red. However the display can't be fixed by indexed color table replacement (which may require separate treatment of each frame!); it would have to be redrawn from raw data.

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1125 on: October 15, 2016, 02:09:32 PM »
Here is a curious bit about the Lincoln Sea that has to affect ice movement, namely Beaumont  Island on the east side. This has been a bone of contention between Denmark and Canada in terms of divvying up the Arctic Ocean for drilling that will never happen, Canada declaring it just a rock barely sticking out of the sea (though it's 10 km2).

However the peak at Beaumont is 0ver 400 meters above sea level and that of John Murray is 800. The whole area between these, Elison and the Greenland mainland -- should its ice volume be assigned to the Lincoln Sea or to an extension of Victoria Fjord?

One thing is for sure: this area is a dead end for ice moving from west to east (ie towards the Fram Strait). It would have to pass up and around, similarly to the KaffeKlubben shoals. It's conceivable that the Innuitan Ice Sheet left glacial striations on Beaumont but that seems to have been much farther to the south. There have been landings but nothing seems published.

Michael

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Re: Latest PIOMAS update (October)
« Reply #1126 on: October 15, 2016, 02:22:02 PM »
PIOMAS gridded data has again had a partial interim update, here are my unofficial figures based on these provisional data.
The volume will undoubtedly be increased when the final official figures are released but this gives a reasonable indication of how the model sees the current situation.

Date    Day    Volume    Avg Thickness
30 Sep 2016    274    4.8508    1.0662
1 Oct 2016    275    4.8917    1.068
2 Oct 2016    276    4.9327    1.068
3 Oct 2016    277    4.9447    1.062
4 Oct 2016    278    4.9647    1.0604
5 Oct 2016    279    4.9704    1.0603
6 Oct 2016    280    4.989    1.0608
7 Oct 2016    281    5.01    1.063
8 Oct 2016    282    5.0419    1.058
9 Oct 2016    283    5.0796    1.0576
10 Oct 2016    284    5.1146    1.0589
11 Oct 2016    285    5.1746    1.0507
12 Oct 2016    286    5.2291    1.0472

[giceday.H2016]

budmantis

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Re: Latest PIOMAS update (October)
« Reply #1127 on: October 16, 2016, 05:45:37 AM »
A-Team: That old satellite image of the Lincoln Sea and Beaumont Island is striking because of widespread fracturing of the pack ice, similar to what happened in the Beaufort Sea earlier this year. Any idea of when that image was taken?
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Re: Latest PIOMAS update (October)
« Reply #1128 on: October 16, 2016, 03:57:54 PM »
For yet another perspective see also the Global Ocean Forecast System (GOFS) 3.1 "HYCOM+CICE" nowcasts for September 30th & October 15th:

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

This one shows 3-4 meter thick ice in the Lincoln Sea, but once again a remarkably small area over 1.5 meters thick Arctic wide.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1129 on: October 17, 2016, 05:38:07 PM »
date of that old satellite image of the Lincoln Sea?
No, it did not come with an associated date. It may be part of the file name but I've lost track of the url, probably came from a google image search for Lincoln Sea, a long runaround. Probably mid 1990's. [Lodger tracks this down below to a Modis from March 2012].

You are quite right, these massive fracture events are not a new development. The ice pack is floating and surprisingly mobile over even a day or two. This thicker ice may be have some anchors along the CAA coast and also, being stronger, be more prone to brittle fracture.

Dispersion is not really an option for it as it is for central areas of loose floes (ice of intermediate concentration). A group actually drilled Lincoln Sea ice during the 1990's so thicknesses are known from direct measurement for those dates. A fixed camp out there seems a bit dicey.

The static image below shows shows the Lincoln Sea at full UH AMSR2 resolution, with sea ice concentration averaged from the fall equinox to the 14th of October. The lower panel is a straight average, the top panel has this enhanced to separate the whites, and the middle false-colors the top to bring out Lincoln Sea regions (notably the area adjacent to Ellesmere which was less that 100% concentration over this period).

 The animation shows the whole Arctic Ocean context for this averaging process with various index color treatments that bring out boundaries within the ice pack. Some of the fringe could be the first gray ice that forms, or pancake ice -- it may be that a satellite signature exists for these (to be discovered by unsupervised k-means classification or support vector machine).
« Last Edit: October 18, 2016, 04:04:28 PM by A-Team »

Artful Dodger

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Re: Latest PIOMAS update (October)
« Reply #1130 on: October 18, 2016, 06:26:43 AM »
A-Team: That old satellite image of the Lincoln Sea... Any idea of when that image was taken?


Hi folks,

A quick Google Image search reveals this image was taken 2012-03-13, approx. 90 min before this one (notice the sea smoke at the N. entrance to Nares Straight, and the position of various unique sea ice floes and leads):

http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201202261322.NOAA.jpg

Hat tip to forum member Arctic.io for the original blog post, still available on their website.  8)

Cheers,
Lodger
« Last Edit: October 18, 2016, 06:31:56 AM by Artful Dodger »
Cheers!
Lodger

budmantis

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Re: Latest PIOMAS update (October)
« Reply #1131 on: October 18, 2016, 07:02:31 AM »
Thanks Lodger! By the way, has the era of procrastination come to a close yet?

Regards,

Bud

P.S. Question: Why don't you post more often? I've always enjoyed your contributions to the blog and forum.
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Re: Latest PIOMAS update (October)
« Reply #1132 on: October 19, 2016, 01:05:11 PM »
Thanks Lodger! By the way, has the era of procrastination come to a close yet?

Hi Bud,

As Winston Churchill once said:
Now this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning.

The ratification of Paris 2015 is IMHO the end of the beginning. Don't expect Big Carbon to give up without a fight though. Inertia wasn't just discovered by Newton, but also by Machiavelli (deniers fight to keep the status quo and prevent action).

: budmantis
P.S. Question: Why don't you post more often? I've always enjoyed your contributions to the blog and forum.

Ahaha, good question! In fact, you may notice that I am User ID #4 on this site, behind Fred (the Administrator), Admin (Fred's other account), and Neven (our Grand Poobah).  :-*

This site has grown in size and influence. Joe Romm, founder of the Climate Progress blog, reposts articles and visualizations created by our membership. We have PhD scientists as regular contributors. We have strength in ideas and in strength in numbers. We have achieved critical mass.

Like Lise Meitner's big idea, our ideas can no longer be ignored. Indeed, Big Carbon and their political henchmen ignore them at our peril. I'd blame Wall Street, but they're too coked up to notice we're about to slam into that wall at 500 kts ppm.

Personally, I like Elon Musk's approach. Use the mechanisms of banking and big business to green the economy. Indeed, let's build the machine that takes down the climate denier machine. That's why I post here. It's what I can do.

But I don't post here for personal agrandization. Ego is a trap, just like excessive wealth, or carbon. When I see a unique opportunity to contribute, I do post (2 new ideas coming soon).

But you guys are already so good, and on top of things all the time. That is my personal satisfaction, seeing the people of good faith contributing openly in this forum.

Thanks, everyone! ;)

P.S. Joe Romm is also fond of saying we need a WWII level of mobilization to deploy green energy solutions. An apropriate analogy, indeed.

Let's ROLL!

Frank Capra Why We Fight (1943) - Youtube 3:50"
« Last Edit: October 19, 2016, 01:42:50 PM by Artful Dodger »
Cheers!
Lodger

abbottisgone

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Re: Latest PIOMAS update (October)
« Reply #1133 on: October 22, 2016, 05:04:52 AM »
Procrastination is next to stagnation: 9-11 happened so of course procrastination is over.

The idea of Jevons Paradox is that the more efficiently we learn to use a resource then the more of that resource we will actually use... imagine if we learnt to use our brains!

I would say more than a world war 2 effort awaits with society taking as long as it needs to change.

Instead of letting polar bears go and kill things in the arctic the new artisans will be saying we must lock them up and start breeding programs: no, wait: let us ( a l s o  ::)) give the polar bear peepholes to protect their privacy in the arctic  :o :o :o :o :o :o :o :o :o <very un-lol>

 :'(
..
But I left school and grew my hair
They didn't understand
They wanted me to be respected as
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seaicesailor

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Re: Latest PIOMAS update (October)
« Reply #1134 on: October 22, 2016, 11:42:03 AM »
It seems to me looking at posts above that for whatever reasons, in this moment HYCOM ACNFS is giving a qualitatively similar picture of the ice thickness as PIOMAS, with Cryosat, SMOS, Ascat. Significant differences but at least they can be compared.
DMI is absolutely inconsistent with all other measure/model ice thickness products. 2m+ ice "blossoming" everywhere like Lovelock's daisies? Invalid and useless.
Hycom GLB is also inconsistent, it basically shows razon-thin ice almost everywhere.
« Last Edit: October 22, 2016, 11:50:10 AM by seaicesailor »

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1135 on: October 22, 2016, 09:13:22 PM »
DMI is absolutely inconsistent with all other measure/model ice thickness products. 2m+ ice "blossoming" everywhere
I just look at the color key to the thicknesses. When there are a dozen uncorrected boners in that already -- in a  palette scheme known already to the ancient Sumerians -- you can expect that the ice thickness graphic will be, as W Pauli put it more recently, not even wrong.

Feeltheburn

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Re: Latest PIOMAS update (October)
« Reply #1136 on: October 23, 2016, 06:16:26 AM »
It seems to me looking at posts above that for whatever reasons, in this moment HYCOM ACNFS is giving a qualitatively similar picture of the ice thickness as PIOMAS, with Cryosat, SMOS, Ascat. Significant differences but at least they can be compared.
DMI is absolutely inconsistent with all other measure/model ice thickness products. 2m+ ice "blossoming" everywhere like Lovelock's daisies? Invalid and useless.
Hycom GLB is also inconsistent, it basically shows razon-thin ice almost everywhere.


I'm not sure I understand how DMI is that different than SMOS:

http://www.iup.uni-bremen.de:8084/smos/
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seaicesailor

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Re: Latest PIOMAS update (October)
« Reply #1137 on: October 23, 2016, 10:24:01 AM »
It seems to me looking at posts above that for whatever reasons, in this moment HYCOM ACNFS is giving a qualitatively similar picture of the ice thickness as PIOMAS, with Cryosat, SMOS, Ascat. Significant differences but at least they can be compared.
DMI is absolutely inconsistent with all other measure/model ice thickness products. 2m+ ice "blossoming" everywhere like Lovelock's daisies? Invalid and useless.
Hycom GLB is also inconsistent, it basically shows razon-thin ice almost everywhere.


I'm not sure I understand how DMI is that different than SMOS:

http://www.iup.uni-bremen.de:8084/smos/

You are right. It was not fair to include SMOS as invalidating DMI. SMOS measurements  about 1 m are invalid, and to avoid the problem uni bremen places the maximum of the range at 0.5 m. In that respect, the maps do not disagree.

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Re: Latest PIOMAS update (October)
« Reply #1138 on: October 23, 2016, 11:28:38 AM »
DMI is absolutely inconsistent with all other measure/model ice thickness products. 2m+ ice "blossoming" everywhere
I just look at the color key to the thicknesses. When there are a dozen uncorrected boners in that already -- in a  palette scheme known already to the ancient Sumerians -- you can expect that the ice thickness graphic will be, as W Pauli put it more recently, not even wrong.

Uh, the only clueless thing is taking a compressed PNG graphic designed to give a quick visual overview and assuming that the actual scientific models and outputs are based on that graphic rather than vice versa. This is the same shit Tony Heller pulls. Stop it.

A-Team

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Re: Latest PIOMAS update (October)
« Reply #1139 on: October 23, 2016, 02:39:24 PM »
the only clueless thing is taking a compressed PNG graphic
Please...png has lossless compression. These are tiny files to begin with.  We're well into the internet age distribution now, not CMYK print journals. The color keys to a map can and should jibe with colors used in the map, period. The UH AMSR2 sea ice concentration maps show there is no effort cost associated to this.

So why do it wrong?  The one dithered here is a classical scientific palette provided at wikipedia. It's just as easy to make a scientific illustration as to make low-grade, dead-end eye candy.

Note tick marks should never be placed within the palette over-writing the key. The boundary box should never be dithered into the palette. The width of tick marks should correspond to bin width (two in the palette below). Thickness values should be clearly tethered to their bin. The number of bins should correspond to the resolving power inherent to the data --  0.01 bin resolution doesn't make sense if thickness resolution error is 0.25m.

In most cases, the palette should be scored for usage of each bin within the data of the map, how much ice is 1.0-1.1 m thick etc etc. Pretty basic to analysis, no? ImageJ will count pixels out into spreadsheet columns. It requires a clean product however.

I can't see the basis for "leaving analysis to IPCC experts" who so far have gotten the Arctic ice, methane, tundra, jet stream, AMOC, Thwaites, etc etc so deadly wrong.

There's actually a technical to trick to making map scoring possible on these crappy visuals: first greatly enlarge the center strip of the palette with no interpolation, then drop from RGB to indexed color at say 4x bin-specified numbers. This forces the tens of thousands of distinct map colors into the nearest (in the natural metric of the color space) bin because index color collapse looks at color usage to determine allowed colors. Now the scoring can go forward, with needless additional error though.

Almost no one ever looks at raw scientific data; the map is all they have time for. So it's best practice to make the map scientific, it costs nothing and a reader might take the next step in exploring the data. Science gets done by people exploring pictured data (ie at the graphical GIS level). They record the steps and re-run the script on the netCDF for slightly better accuracy to make the final graphic product. The exploration stage doesn't get mentioned in the journal article any more than da Vinci's ceiling scaffolding gets mentioned by the Vatican.

It all comes down to suppression, indifference or facilitation of collaboration. Frankly, we can't afford the first two any more -- the pace of climate change is way too fast.

One reason we have so much difficulty comparing daily comparisons of six different ice thickness products is the variable choices of projections, scale, color, and archival location. We've got some rather gross discrepancies here -- what purpose is served by obfuscating comparison? Some of these products are WAY off the mark.

Perhaps you can demonstrate for us how easy it is to compare products at the raw netCDF level by posting a comparison of today's ice thicknesses? Your first problem will be even locating the files.

I'm waiting, Peter. Put up or shut up.
« Last Edit: October 23, 2016, 04:25:08 PM by A-Team »

Pmt111500

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Re: Latest PIOMAS update (October)
« Reply #1140 on: October 23, 2016, 04:49:00 PM »
 
... then drop from RGB to indexed color at say 4x bin-specified numbers. ...

Having done this to a couple of graphs I'd welcome a software which would do this to exactly 12, 22, 42, 52 or 102 colors the extra two being black/white. I know people don't like decimals so not requesting 35. But even that would be easier to use than scan of a photocopy of a jpg.
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Juan C. García

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Re: Latest PIOMAS update (October)
« Reply #1141 on: October 31, 2016, 03:13:14 PM »
Far (no exaggeration here)  below anything else (in my limited set of years) at this time of year:

Update 20161030.

Extent: -26.6 (-1456k vs 2015, -1847k vs 2014, -1786k vs 2013, -716k vs 2012)
Area: -34.9 (-1415k vs 2015, -1782k vs 2014, -1807k vs 2013, -741k vs 2012)

(the 2012 compare is with UniH SSMIS 12.5km, which should be close to the real AMSR2 data when available)

Today's drops in area and extent are partly (CAA dropped fast too) caused by the continuing battle on the Wrangel/Chukchi arms:

With the incredible low refreeze figures that the ASI is having on October 2016, I cannot wait to see the new PIOMAS volume estimates!!!
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

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Re: Latest PIOMAS update (November)
« Reply #1142 on: November 05, 2016, 06:34:30 PM »
Gridded daily thickness data for October is available. From this (hiday file) I estimate that volume for day 305 is 6.534 [1000 km3].

If confirmed, that is lowest for the day, a hair below the value in 2012: 6.547.


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Re: Latest PIOMAS update (November)
« Reply #1143 on: November 05, 2016, 06:48:12 PM »
The animated thickness map. Uncompressed, it seems that some people prefer that.

Therefore you must click the picture to load the 2.6M animation and start it.

Other maps will be posted tomorrow.

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Re: Latest PIOMAS update (November)
« Reply #1144 on: November 06, 2016, 02:22:44 PM »
Thickness maps for October and differences with 2016.

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Re: Latest PIOMAS update (November)
« Reply #1145 on: November 06, 2016, 02:58:15 PM »
Wipneus


Magnificent, as always, but scary as hell.


Any explanation for the apparent loss of thickness in the ice north of Prince Patrick Island in the animation?


Thanks
Terry

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Re: Latest PIOMAS update (November)
« Reply #1146 on: November 06, 2016, 03:34:07 PM »
Great work, as always, Wipneus. Thanks for giving us an analysis as soon as the first numbers appeared on Piomas!

2016 should pass as the year in which we had the lowest extent on the ASI average for the whole year, reaching then the lowest October volume on record (it could be concluded as volume tie with 2012 on October, if some of you prefer this point of view). 2016 should not be cataloged as "being fifth lowest in the satellite record", as NSIDC concludes on their October 5th analysis and as surely will appear on other several analysis, based on this NSIDC conclusion.
« Last Edit: November 06, 2016, 03:51:07 PM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

Juan C. García

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Re: Latest PIOMAS update (November)
« Reply #1147 on: November 06, 2016, 03:44:39 PM »
It is a shame that Piomas erases their comments every month. So, just to keep the information, these are their conclusions for the September 2016 data (published on October):

September 2016 sea ice  volume was 4,500 km3 , about 1300 km3 below the 2015  value and the third lowest for September on record with 2012 being the lowest and 2011 nearly tying 2016.  2016. September  volume was 73% below the maximum September ice volume in 1979,  60% below the 1979-2015 mean, and about 0.5 standard deviations below  the long term trend line.
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

Wipneus

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Re: Latest PIOMAS update (November)
« Reply #1148 on: November 06, 2016, 04:44:59 PM »
The official volume data is now in as well. PIOMAS data is now in. 2016 went below 2012 just at the last day (Day 305).

I updated my graphics, see the top post

The very low volume growth is reflected in the anomaly graph as it is developing into a second minimum.

OSweetMrMath

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Re: Latest PIOMAS update (November)
« Reply #1149 on: November 07, 2016, 04:59:24 PM »
Wipneus, the graphs in the first post do not appear to have the October data. Perhaps there's a cache problem somewhere.

Also, I missed posting my anomaly graph (which computes the anomalies after subtracting the linear trend) last month, but here it is for this month. The slow growth in volume in October is clearly visible as a sharp downturn in the anomaly. A fall in the anomaly this late in the year is quite unusual. Basically the only other year like this was 2007.