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Author Topic: Latest PIOMAS update (July mid-monthly update)  (Read 754951 times)

Jim Hunt

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Re: Latest PIOMAS update (June)
« Reply #1850 on: June 14, 2017, 11:17:01 AM »
Jim, did Chris Reynolds define the various 'seas' anywhere ?

He did indeed. See this new thread on the Developer's Forum:

PIOMAS gridded thickness and regional volume

P.S. See also Wipneus' latest post!



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Jim Hunt

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Re: Latest PIOMAS update (June)
« Reply #1851 on: June 14, 2017, 11:24:12 AM »
Using the regional mask from Chris I have made a daily regional volume data file:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz No checks, but the data looks plausible.

Thanks very much Wipneus. It seems we were typing simultaneously. Astonishingly quick work!

Since the relevant data already exists my plan B might now be to experiment with Zack's code for drawing pretty maps. Have you ever used matplotlib and basemap?

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Wipneus

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Re: Latest PIOMAS update (June)
« Reply #1852 on: June 14, 2017, 12:22:33 PM »
Using the regional mask from Chris I have made a daily regional volume data file:
https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional.txt.gz No checks, but the data looks plausible.

Thanks very much Wipneus. It seems we were typing simultaneously. Astonishingly quick work!

Since the relevant data already exists my plan B might now be to experiment with Zack's code for drawing pretty maps. Have you ever used matplotlib and basemap?

matplotlib: yes, basemap:no

That is probably because I have not attempted to plot maps with python (except dumping arrays to disk as PNG files).

BTW, uploaded https://sites.google.com/site/arctischepinguin/home/piomas/data/PIOMAS-regional-monthly.txt.gz for monthly regional data starting at 1979.

oren

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Re: Latest PIOMAS update (June)
« Reply #1853 on: June 14, 2017, 12:55:04 PM »
Wipneus, thank you x 10. I've been wanting to analyze regional data for a while but couldn't get past the PIOMAS binary files.
Here's a first graph, comparing core Arctic Ocean vs. peripheral volume for end-May (day 151). Interestingly, all of 2017's lead is in the core, leading further credence to the possibility of a new record.
« Last Edit: June 15, 2017, 08:18:18 PM by oren »

oren

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Re: Latest PIOMAS update (June)
« Reply #1854 on: June 14, 2017, 02:25:21 PM »
And a couple more:
The Pacific side volume is running at record low. Some of the missing volume belongs here.
The Atlantic side is running high, with the Greenland Sea at a surprising record high since the year 2000.
It seems the drift/export machine that has been humming for months has taken its toll on volume distribution.

Shared Humanity

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Re: Latest PIOMAS update (June)
« Reply #1855 on: June 14, 2017, 03:31:02 PM »
Wipneus, thank you x 10. I've been wanting to analyze regional data for a while but couldn't get past the PIOMAS binary files.
Here's a first graph, comparing core Arctic Ocean vs. peripheral volume for end-May (day 151). Interestingly, all of 2017's lead is in the core, leading furtherr credence to the possibility of a new record.

Also clear evidence of the fragmentation and increased mobility of the ice pack and the resultant increase in dispersion. The polar ice cap has transitioned into an entirely new state which is easy to see when looking at close up satellite images. Fragmented everywhere.

Shared Humanity

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Re: Latest PIOMAS update (June)
« Reply #1856 on: June 14, 2017, 03:32:00 PM »
I do believe this new state exposes the ice to a flash melt that will shock us when it occurs. Maybe not this year but soon.

Shared Humanity

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Re: Latest PIOMAS update (June)
« Reply #1857 on: June 14, 2017, 03:37:01 PM »
And a couple more:
The Pacific side volume is running at record low. Some of the missing volume belongs here.
The Atlantic side is running high, with the Greenland Sea at a surprising record high since the year 2000.
It seems the drift/export machine that has been humming for months has taken its toll on volume distribution.

What does the Baffin Sea look like?

Neven

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Re: Latest PIOMAS update (June)
« Reply #1858 on: June 14, 2017, 04:52:09 PM »
Thanks for those graphs, oren (and Wipneus, as always, for making all that info available). I've missed those regional PIOMAS graphs, since Chris stopped producing them.
Compare, compare, compare

oren

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Re: Latest PIOMAS update (June)
« Reply #1859 on: June 14, 2017, 04:56:06 PM »
What does the Baffin Sea look like?
Ho hum. Nothing to write home about.

Tor Bejnar

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Re: Latest PIOMAS update (June)
« Reply #1860 on: June 14, 2017, 07:05:20 PM »
What does the Baffin Sea look like?
Ho hum. Nothing to write home about.
I'm not certain about that  :)
With no intra-Nares Strait ice bridge this past winter, Nares Strait has been exporting lots of thin ice into Baffin Bay that it normally doesn't do.  Despite all this extra ice, Baffin Bay is only 'reverting to the mean'.  (The Lincoln Sea ice bridge breaking about May 10 would have had virtually no effect on Baffin Bay ice volume on May 31st, but would have some effect now.)

Interesting that 2007 was also a year with no intra-Nares Strait ice bridge.  It also had Baffin Bay ice volume only 'reverting to the mean.' 

Clearly there are other influences that are significant in determining Baffin Bay ice volume.
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Reallybigbunny

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Re: Latest PIOMAS update (June)
« Reply #1861 on: June 14, 2017, 09:20:18 PM »
According to recent posts in Nares Strait Thread there is a lot of 5-8m ice floating off Newfoundland. This is thought to have been transported via Nares Strait??? Could it possibly have been transported that far since the Nares has been open this year? 

DavidR

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Re: Latest PIOMAS update (June)
« Reply #1862 on: June 15, 2017, 09:05:15 AM »
According to recent posts in Nares Strait Thread there is a lot of 5-8m ice floating off Newfoundland. This is thought to have been transported via Nares Strait??? Could it possibly have been transported that far since the Nares has been open this year?

This seems unlikely. Ice that thick is unlikely to melt out in a single year so it  is quite possible it  has been drifting down Baffin for two or three years. Unless it is concentrated and  covers a particularly large area > 1 km it would not necessarily cross the 15% threshold  to be recorded as extent.  So  Baffin could be reported ice free even with many large icebergs drifting down.
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Jim Hunt

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Re: Latest PIOMAS update (June)
« Reply #1863 on: June 15, 2017, 04:55:33 PM »
It is quite possible it  has been drifting down Baffin for two or three years.

It is even possible that the lumps of old ice arrived via the CAA:

http://GreatWhiteCon.info/2016/09/is-the-northwest-passage-freezing-or-melting/

This is from September 26th last year:
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

FishOutofWater

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Re: Latest PIOMAS update (June)
« Reply #1864 on: June 15, 2017, 09:20:00 PM »
The passages of the CAA opened up last August and September. I tracked blocks of ice from the Arctic into those passages for weeks. I think Jim is onto something. That ice could have worked its way down to Newfoundland. Then again, I wouldn't be surprised if it was Arctic ice from the previous summer that had worked its way into the passages then moved through when the CAA opened up last year.

The thickest ice in the CAA has broken up over the past 2 summers and it may be in even worse shape now.

Rob Dekker

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Re: Latest PIOMAS update (June)
« Reply #1865 on: June 16, 2017, 09:06:07 AM »
Wipneus and Oren, thank you guys !
You are so fast in producing valuable information.

Jim Hunt

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Re: Latest PIOMAS update (June)
« Reply #1866 on: June 17, 2017, 11:17:51 AM »
My own first draft of a "Chris Reynolds style" regional volume graph, based on the monthly data for May:

http://GreatWhiteCon.info/2017/06/facts-about-the-arctic-in-june-2017/#Jun-16

As Wipneus said:

No checks, but the data looks plausible.

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Juan C. García

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Re: Latest PIOMAS update (June)
« Reply #1867 on: June 17, 2017, 01:44:12 PM »
My own first draft of a "Chris Reynolds style" regional volume graph, based on the monthly data for May:

http://GreatWhiteCon.info/2017/06/facts-about-the-arctic-in-june-2017/#Jun-16


Interesting graph Jim. Thanks for making it!

I still see weakness analysing PIOMAS volume. It is interesting that the Central Arctic has lower volume than ever. Also, peripheral places like Greenland Sea, have more volume than normal.

Given that the ice on Greenland Sea will tend to melt and the Central Basin is also weak, seems to me that 2017 have some problems to keep the ice on the Arctic, even if there has been not melt ponds this year.
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.

Tor Bejnar

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Re: Latest PIOMAS update (June)
« Reply #1868 on: June 17, 2017, 06:07:49 PM »
Projecting (via eyeballing) the "Chris Reynolds style" regional volume graph's past 20 years into the future, the CAB may be ice-free in May in 40 or 50 years.
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Re: Latest PIOMAS update (June)
« Reply #1869 on: June 17, 2017, 06:13:07 PM »
Projecting (via eyeballing) the "Chris Reynolds style" regional volume graph's past 20 years into the future, the CAB may be ice-free in May in 40 or 50 years.

The projected additional forcing due to Albedo change from this would be slightly more than a doubling of CO2, except that globally averaged forcing would be focused entirely on the CAB with an average increase of forcing at about +80 W/m^2 per year.
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Re: Latest PIOMAS update (June)
« Reply #1870 on: June 18, 2017, 04:02:14 AM »
Is that assuming that the sky would always be clear?

Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1871 on: June 18, 2017, 12:58:01 PM »
Gridded daily PIOMAS thickness data (hiday) was updated up to 15th June.

By volume here are the data from day 152-166:

 [1000 km3]
array([ 17.957,  17.792,  17.654,  17.509,  17.367,  17.217,  17.069,
        16.888,  16.692,  16.522,  16.346,  16.194,  15.996,  15.814,
        15.624])

First observation: the volume gap with 2012 has been deminished from about 1. 48 down do 0.38 [1000 km3]

Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1872 on: June 18, 2017, 01:03:13 PM »

Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1873 on: June 18, 2017, 01:27:05 PM »
Very little Fram net export in the first half of June, import nearly matches export.

Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1874 on: June 18, 2017, 01:35:55 PM »
The animated thickness for first half of June.

Jim Pettit

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1875 on: June 18, 2017, 01:36:54 PM »
First observation: the volume gap with 2012 has been deminished from about 1. 48 down do 0.38 [1000 km3]

Indeed:


As always: thanks, Wipneus!

Richard Rathbone

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1876 on: June 18, 2017, 01:41:41 PM »
Anomaly looks almost but not quite at a record, though its almost certain to happen, this would be really early for the annual anomaly peak and the blob looks to still be making a contribution, so if anything I reckon the anomaly peak should be late.

oren

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Re: Latest PIOMAS update (June)
« Reply #1877 on: June 18, 2017, 02:57:21 PM »
So I made a "prediction" of sorts for mid-June using the crude indicator of DMI temps.
2010, 2011 and 2016 all cluster at 2.72-2.84 while 2012 dropped 3.59 (1000 km3). As 2017 appears to follow the more usual DMI trajectory, I can extrapolate 2017 to mid-June at 15.34. If this happens 2017 should still lead but by a much smaller lead, ~700 km3.
An updated chart, thanks to the relentless Wipneus. The lead has shrunk even further than my crude extrapolation.
« Last Edit: June 18, 2017, 03:03:17 PM by oren »

Neven

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1878 on: June 18, 2017, 04:11:52 PM »
First observation: the volume gap with 2012 has been deminished from about 1. 48 down do 0.38 [1000 km3]

Holy guacamole!
Compare, compare, compare

jai mitchell

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Re: Latest PIOMAS update (June)
« Reply #1879 on: June 18, 2017, 04:24:42 PM »
Is that assuming that the sky would always be clear?

no
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Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1880 on: June 18, 2017, 04:55:24 PM »
Here are a couple of my "standard" PIOMAS graphs based on merged data.

Wipneus

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1881 on: June 18, 2017, 04:57:03 PM »
A gap can disappear as quickly as it was formed.

ghoti

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1882 on: June 18, 2017, 05:24:04 PM »
The June 15 gridded PIOMAS seems to show solid ice volume in regions where Worldview is showing lots of open water. For example eastern and northeastern Hudsons Bay areas seem to show visible open water. Does it lag or is there some kind of averaging being done across grid cells?

magnamentis

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1883 on: June 18, 2017, 05:33:27 PM »
The June 15 gridded PIOMAS seems to show solid ice volume in regions where Worldview is showing lots of open water. For example eastern and northeastern Hudsons Bay areas seem to show visible open water. Does it lag or is there some kind of averaging being done across grid cells?

well observed, unfortunately each year we come to the point where we can see with our eyes (sat images) that the reality differs from some graphs and semi-official data. still piomas seems to be the most reliable source for volume, all others are even worse, so we have to live with it and use/develop common sense through the help/use of additional input (like sat-images and more)

interestingly sooner or later things fit again, perhaps the error quota, which i cannot quantify, is related to fast developments, means fast decreas/increase combined with alternating states of the ice like in area, extent, fragmentation and mobility.

it would be helpful for us non-scientists if someone how has the necessary know-how and skills would look into this repeating issue and come up with possible explanation or, perhaps, proof those wrong who see a discrepancy. all is possible.
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Jim Hunt

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1884 on: June 18, 2017, 06:23:26 PM »
I updated the daily regional volume data file

Thanks Wipneus. Here's the regional graph for day 166:

http://GreatWhiteCon.info/2017/06/facts-about-the-arctic-in-june-2017/#Jun-18
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Darvince

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1885 on: June 18, 2017, 07:26:12 PM »
Is that assuming that the sky would always be clear?

no
Thanks, I didn't know, as you provided no link, and we see lots of models making some very curious simplifications...

oren

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1886 on: June 18, 2017, 07:28:11 PM »
The June 15 gridded PIOMAS seems to show solid ice volume in regions where Worldview is showing lots of open water. For example eastern and northeastern Hudsons Bay areas seem to show visible open water. Does it lag or is there some kind of averaging being done across grid cells?
My layman understanding: PIOMAS is based on NSIDC grid which is coarse resolution. It uses sea ice concentration data as one of its inputs, so there can't be a discrepancy. However, what you see is the average cell thickness, which includes several thickness bins as well as open water.

Magamentis, I must comment that you are being too suspicious of highly valuable scientific data sources. All explanations are readily available on the web, for scientists and non-scientists alike.

Darvince

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1887 on: June 18, 2017, 07:30:00 PM »
A gap can disappear as quickly as it was formed.
This is very curious, as it almost makes it seem like summer and winter in the Arctic have nothing to do with each other.

StopTheApocalypse

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1888 on: June 18, 2017, 07:35:06 PM »
A gap can disappear as quickly as it was formed.
This is very curious, as it almost makes it seem like summer and winter in the Arctic have nothing to do with each other.

Eh, the gap disappearing seems mostly due to the exceptional melt season of 2012. Seems like 2017 roughly kept pace with many other years.

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1889 on: June 18, 2017, 07:38:38 PM »
The closure of that gap somehow reminds me of the upcoming bicycle racing season - Giro and Tour de France show you almost every day how fast a big advantage can diminish ...
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Re: Latest PIOMAS update (June - mid month update)
« Reply #1890 on: June 18, 2017, 10:40:21 PM »
I updated the daily regional volume data file

Thanks Wipneus. Here's the regional graph for day 166:

http://GreatWhiteCon.info/2017/06/facts-about-the-arctic-in-june-2017/#Jun-18

Ok, so in this thread we see that the anomaly went from 1.48 to .38.  That seems to be pretty indicative of a significant slow down in the pace of melting.  But from my layman's point of view, I would like to point out a couple of things based on Jim's chart and to re-assert the likelihood of a volume minimum in the next month. 

Look at the areas that are higher in volume compared to 2016.  We have Barents, Kara, Greenland and Baffin (leaving aside the CAA).  Based on historical SIE/SIA averages these areas
are going to either melt out or come close to it.  So, yes, I'm intermingling extent/area with volume but despite mixing these metrics, what I would point to is that even with slightly higher than average thickness, given the SIE/SIA current data we would expect volume in these areas to revert to the 2016 figures in the coming month.

The point being that while the slope of the volume curve has moderated significantly recently, I would expect it to still dip well below the record low volume figure in the next 2 to 4 weeks given the extent/area conditions of the regions that I mentioned.

(PS The wild cards, in my way of thinking, are the CAA and the central basin which I don't have a good feel for in the next 2 to 4 weeks.  With that said, this is lurker analysis so take it with a grain of salt.)

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1891 on: June 18, 2017, 10:59:46 PM »
With 2012 catching up that fast I think that there is very little chance the volume record will be broken this year.

From what I have seen, June is the most critical melt month. There is virtually no way to recover from a lack of melt in June. Also, 2012 had a monster August which other years can't expect to duplicate. Even if 2017 roughly traces 2012 over the next 1.5 months I would still give it less than a 10% chance to break the record.

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1892 on: June 18, 2017, 11:45:52 PM »
This is comparison of apples with candyfloss. Weve seen here this week confirmation that the ice is now layers of snow with melted and refrozen crusts that fool sat sensors into believing its all ice beneath them. The insulation means warm salt slush is the majority of what has formed beneath. The salt ice slurry will chill the floating snow for a while to below zero. But volume is certainly lower than piomass is calculating due to density and freeboard ramifications. Likely there will be a sudden crash as soon as a decent stir is administered by a wet warm cyclone.
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Re: Latest PIOMAS update (June - mid month update)
« Reply #1893 on: June 19, 2017, 12:04:01 AM »
Likely there will be a sudden crash as soon as a decent stir is administered by a wet warm cyclone.

As right now?
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A-Team

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1895 on: June 19, 2017, 02:16:02 AM »
Wow! Great progress above.

Do we have Chris’s 2013 regional mask in the form of a piomas grid cell color markup (first image below, from wip’s #1613)?

While regional seas will inevitably be somewhat arbitrary, other groups using other definitions have data resources eg for ‘Chukchi Sea’ that we would like to integrate with sea ice thickness.

I looked at the Beaufort Gyre to see if that could form an objective  basis for defining ‘Beaufort Sea’ but it is completely unworkable. The two deep passages across the Lomonosov Ridge that affect ocean flow structure do not lend themselves to defining regional sea boundaries either.

Probably the best physical considerations for defining natural boundaries are bathymetry and slope, notably the 150m depth contour which defines the continental shelf break-point to the abyss. This generally steers incoming currents and governs tidal vertical eddy and surface wind mixing, and so has a lot to do with peripheral ice bottom melting. The shelf shows up in M Jakobsson’s segmentation analysis of 2003 but the traditional seas not so much.

https://www.researchgate.net/profile/Martin_Jakobsson2/publications

As Hyp notes above, a lot of other mechanisms come in to play as thinner and weaker first-year ice comes to predominate, notably ice freeboard dipping below sea level, turning snow layers into slush and then into 'snow-ice', which might then be covered by later snow. Rain and melt events in both the Arctic and Antarctic may become more frequent, with new layers having odd effects on inputs to the piomas algorithm which is not currently configured to interpret them.

N-ICE2015 also documented storm-induced break-up of snow-loaded floes and loss of buoyancy after basal ice melt. The ice cores below show, in polarized light, how complicated the vertical ice structure can become even 100 km internal to the ice edge.

Snow contribution to first-year and second-year Arctic sea ice mass balance north of Svalbard
MA Granskog et al
http://onlinelibrary.wiley.com/doi/10.1002/2016JC012398/full free
Observations of flooding and snow-ice formation in a thinner Arctic sea ice regime during the N- ICE2015 campaign: influence of basal ice melt and storms
Christine Provost et al  DOI 10.1002/2016JC012011

NSIDC has a new (for me) display tool for Tschudi's sea ice age algorithm (which is largely based on older ice being lighter than newer on radar). Sea ice age has been shown, unsurprisingly, to be highly correlated with ice thickness. However the maps correlate rather poorly with piomas thickness. It would be good to have both as compatible overlays; the one below is in the widely used epsg4326.

http://nsidc.org/soac/sea-ice-age-year.html#seaiceagesequential
« Last Edit: June 19, 2017, 02:36:31 AM by A-Team »

Jim Hunt

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1896 on: June 19, 2017, 11:42:51 AM »
Do we have Chris’s 2013 regional mask in the form of a piomas grid cell color markup (first image below, from wip’s #1613)?

Not that I'm aware of. According to Chris:

Quote
Regions have been calculated by using the Cryosphere Today graphic of regions as a template

I don't think much in the way of "physical considerations for defining natural boundaries" went into defining those
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

oren

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1897 on: June 19, 2017, 12:14:29 PM »
Quote
Regions have been calculated by using the Cryosphere Today graphic of regions as a template
I don't think much in the way of "physical considerations for defining natural boundaries" went into defining those
If I understand correctly the regional masks are supplied in the PIOMAS files and are the NSIDC regions.

Jim Hunt

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Re: Latest PIOMAS update (June - mid month update)
« Reply #1898 on: June 19, 2017, 12:24:34 PM »
If I understand correctly the regional masks are supplied in the PIOMAS files and are the NSIDC regions.

According to Wipneus:

Using the regional mask from Chris I have made a daily regional volume data file

If I understand correctly, "the PIOMAS files" from PSC don't include regional masks.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Thomas Barlow

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Re: Latest PIOMAS update (June)
« Reply #1899 on: June 19, 2017, 02:11:32 PM »
My own first draft of a "Chris Reynolds style" regional volume graph, based on the monthly data for May:

http://GreatWhiteCon.info/2017/06/facts-about-the-arctic-in-june-2017/#Jun-16

Looking at that volume graph for Arctic Ocean only, if I am not mis-reading it, the Kara, Laptev, Beaufort, and Barents are all up a bit, but Arctic Basin, Chukchi and ESS are down, and may wipe out the gains. I think this year volume in the Arctic Ocean is what counts if summer is warm and melt-season is extended. I think there could be a tipping point in the Arctic Ocean volume this year or next year, may not even show up as much on overall extent. What goes on in Greenland Sea and Northwest Passage will be irrelevant if volume plummets in the ocean.
( I sure hope I am wrong.)
« Last Edit: June 19, 2017, 03:54:49 PM by Thomas Barlow »