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Author Topic: Latest PIOMAS update (August 2019)  (Read 1002764 times)

Neven

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Re: Latest PIOMAS update (January)
« Reply #1250 on: January 08, 2017, 09:07:52 PM »
PIOMAS January 2017 is up on the ASIB.
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DrTskoul

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Re: Latest PIOMAS update (January)
« Reply #1251 on: January 08, 2017, 10:04:25 PM »
Based on these figures we are starting 2017 with approximately 20% less ice than 2012.  That  suggests we have a lot of catching up to do to to  recover to  2012 levels.

Can you please explain how a drop of 12,195km3 (Dec 2012) to 11,200km3 (Dec 2016) results in 20% less ice? It doesn't in any type of mathematics that I know.

20℅ less than start of 2016..

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1252 on: January 09, 2017, 12:29:34 AM »
Here is the year 2016 in review from Zack. December over the years may be available tomorrow; November was posted a while back.
« Last Edit: January 09, 2017, 12:35:07 AM by A-Team »

DavidR

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Re: Latest PIOMAS update (January)
« Reply #1253 on: January 09, 2017, 03:15:43 AM »
Based on these figures we are starting 2017 with approximately 20% less ice than 2012.  That  suggests we have a lot of catching up to do to to  recover to  2012 levels.

Can you please explain how a drop of 12,195km3 (Dec 2012) to 11,200km3 (Dec 2016) results in 20% less ice? It doesn't in any type of mathematics that I know.
It's closer to 12 percent. That number (20%) evidently came from mistakenly combining a daily value with an average which made the difference seem larger.
You  are comparing the Dec 2012 figure with Dec 2016. You  need to  compare the Dec 2011 figure with  Dec 2016 to see how much worse the situation is at the start  of 2017 compared with the start  of 2012.  It  is as I  pointed out  about  a 20% difference.
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Re: Latest PIOMAS update (January)
« Reply #1254 on: January 09, 2017, 04:53:50 AM »
You  are comparing the Dec 2012 figure with Dec 2016. You  need to  compare the Dec 2011 figure with  Dec 2016

A classic "off-by-one error", as we like to say in computer science. :-)

Tigertown

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Re: Latest PIOMAS update (January)
« Reply #1255 on: January 09, 2017, 05:00:59 AM »
@ DavidR
You are right that is what we were comparing, but the difference in the beginning of 2012 compared to the beginning of 2017 is still only about 13%. Nobody on here is stating whether they are referencing daily values or monthly averages, and that causes a lot of confusion. The only way to get close to 20% that I see is to take the daily value of the last day of 2011 or first day of 2012 and compare it to the Dec. 2016 monthly average of 11,200 instead of the daily value of Dec. 31st which is 13,078. Not that we are that much better off. Anyway, if I am doing something wrong, please let me know what, so I can get it straightened out. I am just going by the numbers that I have.
« Last Edit: January 09, 2017, 05:08:49 AM by Tigertown »

DavidR

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Re: Latest PIOMAS update (January)
« Reply #1256 on: January 09, 2017, 05:19:44 AM »
@ DavidR
You are right that is what we were comparing, but the difference in the beginning of 2012 compared to the beginning of 2017 is still only about 13%. Nobody on here is stating whether they are referencing daily values or monthly averages, and that causes a lot of confusion. The only way to get close to 20% that I see is to take the daily value of the last day of 2011 or first day of 2012 and compare it to the Dec. 2016 monthly average of 11,200 instead of the daily value of Dec. 31st which is 13,078. Not that we are that much better off. Anyway, if I am doing something wrong, please let me know what, so I can get it straightened out. I am just going by the numbers that I have.
My Original estimate was taken from eyeballing the 2000 K difference between the EOY  figures on the graph. I rather foolishly calculated that as about 20% of the 2016 eoy figure rather than 15%  of the 2011 EOY figure. The key take out  is the big discrepancy  between Dec 2011 and Dec 2016.
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Tigertown

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Re: Latest PIOMAS update (January)
« Reply #1257 on: January 09, 2017, 05:28:21 AM »
Well, I hope you don't think I was trying to show you up by any means, as that was not my intention. It was simply bugging the daylights out of me trying to figure  out where the discrepancy was. I agree with your assessment of the situation. It does not look good. As jai mitchell pointed out, it looks like we are on an exponential rate of volume decline after all.

anthropocene

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Re: Latest PIOMAS update (January)
« Reply #1258 on: January 09, 2017, 07:55:13 AM »
@ DavidR
You are right that is what we were comparing, but the difference in the beginning of 2012 compared to the beginning of 2017 is still only about 13%. Nobody on here is stating whether they are referencing daily values or monthly averages, and that causes a lot of confusion. The only way to get close to 20% that I see is to take the daily value of the last day of 2011 or first day of 2012 and compare it to the Dec. 2016 monthly average of 11,200 instead of the daily value of Dec. 31st which is 13,078. Not that we are that much better off. Anyway, if I am doing something wrong, please let me know what, so I can get it straightened out. I am just going by the numbers that I have.
My Original estimate was taken from eyeballing the 2000 K difference between the EOY  figures on the graph. I rather foolishly calculated that as about 20% of the 2016 eoy figure rather than 15%  of the 2011 EOY figure. The key take out  is the big discrepancy  between Dec 2011 and Dec 2016.


Ah, OK now I see where the figure is coming from. Apologies, I was most probably being picky. It's just that the state of the ice is bad enough. A statement like "ice volume is now 20% below 2012 (which was record low)" is one of those memes that can quickly take off across the internet. If the statement can then be proven to be an exaggeration by deniers then it  can be used to damage the climate change narrative. I don't want this site to be the source of such memes.
So we don't need to be eyeballing figures - can we have a permanent link to PIOMAS figures which come before those listed on the first page of this thread e.g. Make a more explicit link to the table at the bottom of https://sites.google.com/site/arctischepinguin/home/piomas/ and update the table for Nov & Dec 2016?  Comparison to the previous minimum(s) is a common task (although it seems 2012 won't be the minimum(s) for long  :( ).

johnm33

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Re: Latest PIOMAS update (January)
« Reply #1259 on: January 09, 2017, 11:21:36 AM »
Looking at Zacks animation posted above by A-Team l'm wondering if the concentration of mass north of Greenland is caused by wave action, [generated on Greenlands north shore by ice movement?], that's driving the larger peices off the continental shelf?

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1260 on: January 09, 2017, 02:35:17 PM »
Here is the latest monthly death spiral from Andy Lee Robinson. The points represent monthly average; it would be vastly more complex to have the daily intermediate points but not look that different (?) in the end. The original is slightly larger and located at the link below.

https://haveland.com/share/arctic-death-spiral.png

Peter Wadhams gave a lucid summary on Sept 16th of the developments we discuss here at such length:

http://e360.yale.edu/feature/as_arctic_ocean_ice_disappears_global_climate_impacts_intensify_wadhams/3037/

The central feature shown in recent Piomas monthly and November daily data conflicts strongly with traditional CAA thickest ice (as shown still in hycom thickness).

The animation below looks at the vastly improved resolution of a 06 Jan 17 Sentinel 1A observational scene (which neither Piomas nor Hycom utilize). Even at 1/6th of its full resolution (first overview frame with red lat-long grid), there seems to be no correlation of either its ice features or gray tones with the thickness and age maps, a bit disturbing to say the least.

The second frame is at full resolution 'as-is' from PolarView. Subsequent frames investigate the very dark ice by bumping contrast in steps, not with entry-level global adjustment tools but rather using staged CLAHE adaptive local contrast from ImageJ.

These frames establish that even the darkest areas are indeed ice, perhaps former open water between floes that froze in at some point and now is smooth because of this history and presumably at lesser thickness than the old white floes (which have had the same thermodynamic opportunities to thicken).

Alternatively, as discussed earlier from AMSR2 appearance and persistence, these may represent snow, snow melt, or after effects of rain on snow from the moisture event around 24 Dec 16.

The coarse products we use here, eg those with the perpetually confusing "15%" rule, are using pixels far too large to resolve anything shown in any of these frames. This is the second year of Sentinel coverage; the purpose of continuing with these products escapes me. We need to get on with what is really out there.

It would be helpful to have Cryosat or IceBridge observational thickness overlays even though these are just thin scan lines (transects). Unfortunately neither serves data from a user-friendly portal; IceBridge may not fly in mid-winter.

Some of these projects, despite every penny coming from the public, seek to bury the data so that scientists involved get a publication 'scoop' even though it may take two years or more to appear and not be what we need even then.
« Last Edit: January 09, 2017, 03:16:28 PM by A-Team »

seaicesailor

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Re: Latest PIOMAS update (January)
« Reply #1261 on: January 09, 2017, 02:52:41 PM »
...
The central feature shown in recent Piomas monthly and November daily data conflicts strongly with traditional CAA thickest ice (as shown still in hycom thickness).
...

The site
http://www.cpom.ucl.ac.uk/csopr/seaice.html
permits to select some tiles to see a more detailed representation of Cryosat data. The attached tiles (merging data from December 10 October 12 to January 6) show indeed regions where the output thickness is pretty low interspected with the thicker ice that one would expect North of Greenland and CAA.
A very difficult state of ice to be modelled maybe? Something intermediate between HYCOM and PIOMAS
« Last Edit: January 09, 2017, 03:01:56 PM by seaicesailor »

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1262 on: January 09, 2017, 05:55:13 PM »
Thanks for the link! The portal has been greatly improved. The date convention is parochial and ambiguous and needs to be fixed, as does the pole-hole clutter; the projection is compatible with Hycom, WorldView and PolarView though the orientation is off by -45º; palette errors are minor; single time-stamped tracks appear to be requestable, a proper variety of file formats are available for download, and volume swath integrals are provided.

But merging orbital thickness tracks over 27 days? It would seem to compare early orbits with later, possibly 'adjacent' orbits by which the ice has thickened, seen as radial streaks in Cryosat below. And we've seen ice move so much in a single day that everything would be thrown out of register a few orbits later.

Is there a practical way to correct for that motion? Yes, use the same scheme as UWisc did to advect TPW, it's open source and daily motion vectors are at NSIDC. That could yield thickness time series for individual parcels.

Meanwhile, a comparison is needed of the 10 Dec 15 to 06 Jan 17 Cryosat merger to the same 28 dates for daily Hycom ice thickness (being careful that none of the dates used there are forecasts, eg by unoptimizing the last 365 day product served on Jan 9th and deleting down to the date range).

Note first because Hycom, Cryosat and commonsensical cold-pole FDD independently agree along the CAA, it follows that Piomas is very wrong about December and appears not worth pursuing in this context.

However Piomas too provides a daily whole Arctic map series over this same time interval whereas Cryosat (like all narrow swath near-polar satellites) has a data pole-hole. So it may be worth looking at where and why Piomas is going wrong and perhaps how to correct and use it.

Neither CPOM nor Hycom are in standard 'Greenland down' position, differing by ±45º. Both have palette errors, meaning you cannot pull up all the ice of a given thickness range; the Cryosat is not bad whereas Hycom remains deep in the digital cartographic past. Since neither color scheme was worth preserving, both are re-oriented below into Nasa/NSIDC position with a 206.20% scale increase for Hycom.

To facilitate comparison, ideally both would be assigned the same thickness color scheme. That hasn't been feasible since neither uses a rational palette scheme; below Cryosat is held constant over the date range, as colored and as inverted, while Hycom is run through each date in turn.

The second animation shows a differencing scheme of thickness comparison (to Jan 6th Hycom only) that is not entirely satisfactory either.

The third shows SMOS ice thinness of Jan 6th compared to Hycom of the same date and Cryosat over the 28 day range ending on the 6th. There's fair agreement but inconsistency all around.

There's a trick for exiting palette silos, so the question is what makes for the best hybrid thickness model, eg SMOS on thin, Cryosat elsewhere, as modified by morphing ice. However even if were spot-on accurate and Arctic ice volume crashing, it's not clear who is listening. P Wadhams has said it all already and very well:

http://e360.yale.edu/feature/as_arctic_ocean_ice_disappears_global_climate_impacts_intensify_wadhams/3037/
« Last Edit: January 09, 2017, 07:38:01 PM by A-Team »

DrTskoul

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Re: Latest PIOMAS update (January)
« Reply #1263 on: January 09, 2017, 08:19:38 PM »
Differences notwithstanding, a lot of thick ice is poised for Fram export!

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1264 on: January 09, 2017, 10:58:11 PM »
Here are comparisons of December ice thickness per Piomas and volume loss during the satellite era (both from wwizard @ZLabe).

Glenn Tamblyn

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Re: Latest PIOMAS update (January)
« Reply #1265 on: January 10, 2017, 07:23:45 AM »
The difference between Dec 2011 and Dec 2016 is 1783 km^3.

So if the 2017 season just matches 2012 for delta V, that puts it at around 2000 km^3 for Sep 2016. Nearly half!

budmantis

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Re: Latest PIOMAS update (January)
« Reply #1266 on: January 10, 2017, 07:30:52 AM »
Great visuals A-Team. Thanks!

Juan C. García

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Re: Latest PIOMAS update (January)
« Reply #1267 on: January 10, 2017, 06:47:42 PM »
Great visuals A-Team. Thanks!

The true is that I miss Wipneus visuals on this month.
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.

FishOutofWater

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Re: Latest PIOMAS update (January)
« Reply #1268 on: January 10, 2017, 10:33:32 PM »
The thickest ice well north of Greenland is caused by wind convergence. Usually the thickest ice is near the shores of Greenland and the Canadian archipelago as the transpolar drift caused by winds blowing off of Siberia piles up ice on the North American side of the Arctic ocean. This year the storms in the Barents sea that pushed into the central Arctic have changed the convergence patterns. Now the ice is piled up on its way to the Fram out of the Arctic.

Not good.

Image shows that anomalous southerly winds blew into the Arctic from the Barents and Kara seas. This caused a pile up of ice where it converged with ice being taken by currents towards the Fram strait.


Wipneus

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Re: Latest PIOMAS update (January)
« Reply #1269 on: January 11, 2017, 08:34:03 AM »
Great visuals A-Team. Thanks!

The true is that I miss Wipneus visuals on this month.

Me too! Still no daily gridded data update yet.

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1270 on: January 11, 2017, 11:34:55 AM »
Quote
Me too! Still no daily gridded data update yet.
Meanwhile, the show goes on at CPOM Cryosat. Some progress on extracting ice thickness data for forum-level analysis:

-- Using open source GUI freeware Panoply to open the netCDF file, it is quite easy make nice displays and also to export the data to plain csv text. There it seems the various orbital tracks are run together but using the lat,lon it would be feasible to extract a single orbit (ie a transect of your region of interest) and compare ice thicknesses to Piomas on the same dates as that becomes available.

-- The geotiff file provided opens directly in Google Earth Pro freeware using the 'Import' command as a properly positioned overlay over the Arctic Ocean. The issue is transparency: somewhere along the line the alpha channel has been lost. This causes the CPOM geotif to have a white background off-orbit, rather than allow a clear overlay. The workaround below takes two screenshots, one with the import suppressed and another with it opaque. The two are layered in Gimp with the white on top; it is is then removed to let google earth shine through.

Geotiff is one of many annoying 'bundled' file formats in which all sorts of extraneous metadata (~ commented-out lines in code) prefaces the image pixel data. This siloing causes all sorts of problems in photoshop-type software, which will open the geotiff but delete its metadata. That's because common operations like cropping, rotation, and resizing don't know how to co-transform the geo information.

However this means a great many important enhancements that leave the image compatible with its geo referencing data can't be done without the major nuisance of removing the geo and putting it back in at the end. And let's face it, most gis software doesn't come remotely close to replicating photoshop.

Putting aside Cryosat vs Hycom vs Piomas ice thickness comparisons for the moment, I looked at putting Sentinel-1AB into a common meeting ground provided by google earth. In effect, this would lay ice thicknesses over specific floes and tonal features provided timestamps were close enough. However reprojection  degrades image quality too much.

It is easier to overlay Cryosat onto Roberto Saldo's fabulous collection of one-day Sentinel-1AB 1km mosaics at DTU http://www.seaice.dk. The links to those -- and Envisat for multi-year comparisons -- can be built by editing the sample urls below. Saldo has been at this since 2005 and today is processing 400 mega images a day into cross-correlated motion.

The animation shows export towards the Fram and Nares in the Lincoln Sea area between 20 Dec 16 and 10 Jan 17, using DTU mosaics reprocessed as inverted, adaptively re-contrasted, false color 6-bit. The ice in this area jiggles around quite a bit but does not much net transport out of the Arctic over this time frame

http://www.dtu.dk/english/service/phonebook/person?fr=1&id=2950&mr=100&qt=dtupublicationquery&tab=2#tabs

http://north.seaice.dk/2017/01/10/20170110.s1ab.1km.n.mos.jpg
http://north.seaice.dk/2017/01/09/20170109.s1ab.1km.n.mos.jpg
http://north.seaice.dk/2017/01/08/20170108.s1ab.1km.n.mos.jpg

http://north.seaice.dk/2007/01/10/20070110.envisat.n.GMMmos.jpg
http://north.seaice.dk/2011/01/10/20110110.envisat.n.GMMmos.jpg
http://north.seaice.dk/2012/01/10/20120110.envisat.n.GMMmos.jpg

FishOutofWater

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Re: Latest PIOMAS update (January)
« Reply #1271 on: January 11, 2017, 05:47:33 PM »
The orange blue contrast is great for visualization. The flow out the Nares is impressive in the animation. The imagery would need to be extended eastwards to see exactly how much ice is flowing out the Fram, but it's clear there is a surge late in the animation.

jdallen

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Re: Latest PIOMAS update (January)
« Reply #1272 on: January 11, 2017, 07:38:13 PM »
The orange blue contrast is great for visualization. The flow out the Nares is impressive in the animation. The imagery would need to be extended eastwards to see exactly how much ice is flowing out the Fram, but it's clear there is a surge late in the animation.
Nares is also notable for the fact that its driven primarily by current rather than weather.

With the ice thinning as it has, we no longer have the Lincoln sea "Arch" of thicker ice getting set up to protect the pack from that flow.  Without it, we may be approaching 1000KM2/day of ice exiting that route.

That pales compared to the flow out of the Fram and elsewhere, but it's like a slowly leaking tear in some important blood vessel that can't be repaired.

-J
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shmengie

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Re: Latest PIOMAS update (January)
« Reply #1273 on: January 11, 2017, 07:52:05 PM »
The orange blue contrast is great for visualization. The flow out the Nares is impressive in the animation. The imagery would need to be extended eastwards to see exactly how much ice is flowing out the Fram, but it's clear there is a surge late in the animation.

The impression I get is that the "flow" is stifled by tidal surge.  But I'm no fish  ;-)
Professor Trump, who'd thought it was that complicated?

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1274 on: January 11, 2017, 10:57:36 PM »
The 'eastern' part of the 20 Dec - 10 Jan 17 Fram export was posted earlier over at the 2016/17 melt season forum, along with the plan for measuring area, compression, and volume during the course of the impending storm (especially if it materializes!).

As mentioned earlier, Roberto Saldo of DTU posted some fancy longer term animations and also provides Envisat mosaics for much earlier years. See http://www.seaice.dk for links:

Sentinel 1A Lincoln Sea animations 2014/15
Sentinel 1A Lincoln Sea animations 2015/16
Sentinel 1A North Greenland/Arctic Sea animations 2015/16
Sentinel 1A Arctic animations 2015/16

Does any of this really provide a seasonal or 'climate' baseline by which we could say wow export really soared an unprecedented amount during the storm, by xxx% over the daily mean for this date for σ = y.z standard deviations and this -- being pqr% of the residual ice thicker than 1.5m -- implies blah blah blah about the next melt season?

The focus for now has to be on just documenting the event. That monitoring will probably need to continue for five days or more after the storm to provide context that reaches out beyond mere export. Although hundreds of journal articles have studied Fram export, those will not provide much future guidance for what comes next.

http://forum.arctic-sea-ice.net/index.php/topic,1611.msg98824.html#msg98824

« Last Edit: January 11, 2017, 11:24:21 PM by A-Team »

seaicesailor

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Re: Latest PIOMAS update (January)
« Reply #1275 on: January 11, 2017, 11:46:08 PM »
It is for day 6 now, ecmwf showing the ~940 hPa low, but starting in day 5 already pretty low ~960 hPa right over Fram Straight and then wandering around the Arctic for two or three days below 970 hPa.
May or may not be that strong but I think we are going to see some action
PS. It animates after a click

Tigertown

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Re: Latest PIOMAS update (January)
« Reply #1276 on: January 11, 2017, 11:56:30 PM »
That made me dizzy.

magnamentis

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Re: Latest PIOMAS update (January)
« Reply #1277 on: January 12, 2017, 12:03:30 AM »
TROPICAL Tidbits LOL, let's hope that:  "Nomen ≠ Omen" in the near future referring to tropical storms, not yet to tropical temps.  8) ;)


jdallen

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Re: Latest PIOMAS update (January)
« Reply #1278 on: January 12, 2017, 12:32:10 AM »
It is for day 6 now, ecmwf showing the ~940 hPa low, but starting in day 5 already pretty low ~960 hPa right over Fram Straight and then wandering around the Arctic for two or three days below 970 hPa.
May or may not be that strong but I think we are going to see some action
PS. It animates after a click
960 is plenty bad enough.
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FishOutofWater

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Re: Latest PIOMAS update (January)
« Reply #1279 on: January 12, 2017, 02:40:11 AM »
It looks like a large amount of thin ice has been melted by storms and waves before it reached the Fram strait. Much of the cold fresh melt water on the Greenland side of the Arctic ocean will be transported out of the Arctic along with the remaining ice.

I'm trying to follow the storage and transport of fresh water in the Arctic.  This storm track may drive fresh water through the CAA "garlic press".

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1280 on: January 12, 2017, 06:21:00 PM »
Quote
trying to follow the storage and transport of fresh water in the Arctic.  This storm track may drive fresh water through the CAA "garlic press".
Presumably referencing here the many papers of oceanographer Andrey Proshutinsky on surface freshwater accumulation attributable to Ekman pumping consequent to the (former?) Arctic High anticyclonic circulation centered on Beaufort Gyre. He has the freshwater exiting to the North Atlantic, so to the CAA would be a new twist; that region unfortunately has infrequent Sentinel-1AB mosaic coverage.

http://www.whoi.edu/oceanus/feature/signs-of-big-changes-in-the-arctic

"For at least half a century and probably longer, the climate in the Arctic has run like a clock. As reliably as a pendulum, it has oscillated every five to seven years between two distinct self-regulating phases that shift the region’s winds, ice, currents, and other conditions.

But in a new study ("Arctic Circulation Regimes": http://rsta.royalsocietypublishing.org/content/373/2052/20140160), scientists say the system has been stuck in one phase since 1997. The monkey wrench that’s jamming the works, they suspect, may be warming temperatures that are accelerating the melting of the Greenland Ice Sheet.

Arctic climate is regulated by an intricate series of interconnected mechanisms, said Andrey Proshutinsky, a physical oceanographer at Woods Hole Oceanographic Institution (WHOI) and lead author of the new study. At the center of the whole Arctic climate system is the Beaufort Gyre—a swirling wind-driven circulation cell north of the Beaufort Sea that encircles an area larger than the Gulf of Mexico.

It works like this: During some multiyear periods, the Arctic is cold and dry and dominated by high atmospheric pressure that sets in motion strong anticyclonic (clockwise) winds over the Beaufort Gyre region. The winds drive the powerful clockwise-circulating Beaufort Gyre. The cold thickens sea ice. The gyre encircles a huge reservoir of sea ice and fresh water that drains into the region from many big northern rivers and the Bering Strait. The gyre corrals this pool of ice and fresh water, preventing it from flowing southward into the North Atlantic Ocean.

During other periods, however, this complex ocean-ice-atmosphere system shifts gears. Cyclonic storm systems that form in the North Atlantic move up into the Arctic, bringing heat and moisture. The Arctic atmosphere becomes relatively warm and humid. Atmospheric pressure decreases, causing winds to reverse. The gyre weakens and its circulation turns counterclockwise.

The huge pool of trapped sea ice and fresh water then leaks out and flows out of the Arctic Ocean and into the North Atlantic. This creates a layer of cold but less dense water that caps the surface of some parts of the North Atlantic. The layer blocks heat from the ocean from escaping into the atmosphere and tempering wintertime climate in the North Atlantic region..."
« Last Edit: January 12, 2017, 06:48:27 PM by A-Team »

FishOutofWater

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Re: Latest PIOMAS update (January)
« Reply #1281 on: January 12, 2017, 06:41:56 PM »
Yes, A.P.'s work has also been an important part of the "Arctic Report Cards".

It is critical work in understanding the linkages between weather and sea ice. Modest fresh water surges can slow down the AMOC for several years or more, affecting NH weather.

jai mitchell

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Re: Latest PIOMAS update (January)
« Reply #1282 on: January 12, 2017, 07:44:13 PM »
I recall Beaufort Gyre movement in a strong clockwise motion this year, more than I have ever seen.

well. . . until we had open water. . . :o

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Re: Latest PIOMAS update (January)
« Reply #1283 on: January 14, 2017, 12:29:55 PM »
Gridded daily PIOMAS thickness data for December is in.

First the average thickness for December map, compared with previous years.

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Re: Latest PIOMAS update (January)
« Reply #1284 on: January 14, 2017, 12:35:19 PM »
And here is the animated sequence for December. Click to start.

oren

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Re: Latest PIOMAS update (January)
« Reply #1285 on: January 14, 2017, 12:39:43 PM »
I must say the PIOMAS location of the thick ice is very strange.

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Re: Latest PIOMAS update (January)
« Reply #1286 on: January 14, 2017, 01:55:08 PM »
I must say the PIOMAS location of the thick ice is very strange.

Indeed. What happens to that thickest ice when the thin(ner) fast ice along the shore disappears? Does it speed southeast toward and through the Fram Strait like a house fly in a bathtub headed toward the drain? Does it ground itself along the shores of Greenland and Ellesmere once that thin ice is gone? Or does it slowly melt in situ?

Going to be an, er, "interesting" year.

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Re: Latest PIOMAS update (January)
« Reply #1287 on: January 14, 2017, 02:09:28 PM »
Below, the multi-year comparison is re-worked into an animation at slightly larger size. Below that the December daily is cropped to the Arctic Ocean and shown in conjunction with simultaneous SMOS thin ice. It might actually make sense to cover up piomas on the edges with SMOS as accuracy would be complimentary (or so they say).
« Last Edit: January 14, 2017, 03:04:27 PM by A-Team »

Wipneus

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Re: Latest PIOMAS update (January)
« Reply #1288 on: January 14, 2017, 03:31:36 PM »
Side by side animation PIOMAS and ADS/Jaxa thickness. Needs a click.

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1289 on: January 14, 2017, 06:29:26 PM »
Does ADS/Jaxa thickness provide near real-time daily thickness maps up to 13 Jan 17 at a convenient link?

In the multiplexed triphasic animation below which is done for synchronization and compressional information integration, the embedded SMOS thin ice map continues the ADS/Jaxa map (which stops on 31 Dec 16) up to Jan 12th whereas the Hycom modeled thickness continues into six days of forecasting beyond that ending on Jan 17th.
« Last Edit: January 14, 2017, 09:51:30 PM by A-Team »

Wipneus

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Re: Latest PIOMAS update (January)
« Reply #1290 on: January 14, 2017, 07:09:53 PM »
Does ADS/Jaxa thickness provided near real-time daily thickness maps up to 13 Jan 17 at a convenient link?

https://ads.nipr.ac.jp/vishop/data/jaxa/data/201701/AM2SI20170113D_SIT_NP.png
and
https://ads.nipr.ac.jp/vishop/data/jaxa/data/201701/AM2SI20170113A_SIT_NP.png

change year/month on two places and day once for other dates.

A-Team

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Re: Latest PIOMAS update (January)
« Reply #1291 on: January 14, 2017, 10:28:36 PM »
Quote
change year/month on two places and day once for other dates.
Thx for links, very helpful. The A and D files for the same date refer to ascending and descending orbits.

Have you looked into differencing Piomas and ADS/Jaxa? It seems the palette colors and thickness bins are not conducive to this as it stands. So it might be necessary to go back to adam & eve with the .nc arrays, do the differencing there, and re-map.

Regardless of interpretability, below this is done splitting the side by side pair provided in #1288.

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Re: Latest PIOMAS update (January)
« Reply #1292 on: January 15, 2017, 01:57:50 AM »
Side by side animation PIOMAS and ADS/Jaxa thickness. Needs a click.
I'm fascinated by the JAXA animation - it appears a large block of thicker ice was destroyed by being forced into the "hot zone" north of Svalbard.
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A-Team

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Re: Latest PIOMAS update (January)
« Reply #1293 on: January 15, 2017, 01:47:29 PM »
Quote
it appears a large block of thicker ice was destroyed at the 'hot front' north of Svalbard
Good spotting. Note too in the Lincoln Sea that the persistent loop of thicker ice shown in Hycom appears in ADS-Jaxa as well.

The 16-17 Dec 16 event is shown enlarged 3x below. On these, sometimes an abrupt change in palette color can create the appearance of a dramatic event that was actually a gradual transition in thickness. However that wasn't the case here, though the issue of thickness accuracy remains unsettled in view of contradictory thickness products.

To follow up further, you might (1) retrieve the ADS/Jaxa days for November and October to see where the thick block came from (ie de novo or longstanding), (2) tie into the 1990-2016 NASA ice age video (which is weekly and extends to the end of November), (3) retrieve DTU mosaics sandwiching the event, (4) retrieve the higher resolution Sentinel-1AB from PolarView and the originals from ESA if needed, and (5) bring in Cryosat and reanalyses of SST, 2m air, MSLP and wind for the applicable dates.

This will work out because of the nature of near-polar orbits -- the region of interest receives daily or even twice daily coverage at ~10m resolution regardless of weather.
« Last Edit: January 15, 2017, 02:10:54 PM by A-Team »

epiphyte

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Re: Latest PIOMAS update (January)
« Reply #1294 on: January 15, 2017, 09:14:12 PM »
Quote
it appears a large block of thicker ice was destroyed at the 'hot front' north of Svalbard
[...]
To follow up further, you might (1) retrieve the ADS/Jaxa days for November and October to see where the thick block came from (ie de novo or longstanding), (2) tie into the 1990-2016 NASA ice age video (which is weekly and extends to the end of November), (3) retrieve DTU mosaics sandwiching the event, (4) retrieve the higher resolution Sentinel-1AB from PolarView and the originals from ESA if needed, and (5) bring in Cryosat and reanalyses of SST, 2m air, MSLP and wind for the applicable dates.
[/quote]
Just from eyeballing the last few frames of 2) above it looks to have been open water just to the southwest of the laptev bite in early Sep 2014, led a charmed life as rubble somewhere just east of the pole through 2015, firmed up almost on top of the pole over winter 2015/2016, and headed directly south along the meridian over last summer, winding up north of Svalbard in Sep 2016. (see below)

Given that it has spent much of its existence under dubious freezing conditions at best, might one speculate that it wasn't as robust as the models might expect for third year ice? If so, that might help explain why it didn't put up much of a fight...

« Last Edit: January 15, 2017, 09:19:54 PM by epiphyte »

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Re: Latest PIOMAS update (January)
« Reply #1295 on: January 16, 2017, 12:42:33 AM »
The one that is the real scientific treasure trove is this 1990-2016 Nasa treatment of M Tschudi's sea ice age (~thickness) data: mesmerizing to watch at full screen. It was in the 2016 Report Card too. You're quite right that un/remarkable needs further work to sort out here.

https://www.climate.gov/news-features/videos/old-ice-arctic-vanishingly-rare

"In the 2016 Arctic Report Card, scientists wrote:

In 1985, 16% of the ice pack (relative to the total sea ice areal coverage) was four years old and older, but by March 2016 old ice only constituted 1.2% of the ice pack. First-year ice now dominates the ice cover, comprising about 78% of the March 2016 ice pack, compared to about 55% in the 1980s."

Surely the data underlying youtube has been reprocessed somewhere for vorticity, shear, and velocity fields (since Tschudi/NSIDC made it by particle tracking) but it may only surface in some dry static journal figure rather than a dynamic format.
« Last Edit: January 16, 2017, 12:49:51 AM by A-Team »

magnamentis

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Re: Latest PIOMAS update (January)
« Reply #1296 on: January 16, 2017, 11:07:36 AM »
The one that is the real scientific treasure trove is this 1990-2016 Nasa treatment of M Tschudi's sea ice age (~thickness) data: mesmerizing to watch at full screen. It was in the 2016 Report Card too. You're quite right that un/remarkable needs further work to sort out here.

https://www.climate.gov/news-features/videos/old-ice-arctic-vanishingly-rare

"In the 2016 Arctic Report Card, scientists wrote:

In 1985, 16% of the ice pack (relative to the total sea ice areal coverage) was four years old and older, but by March 2016 old ice only constituted 1.2% of the ice pack. First-year ice now dominates the ice cover, comprising about 78% of the March 2016 ice pack, compared to about 55% in the 1980s."

Surely the data underlying youtube has been reprocessed somewhere for vorticity, shear, and velocity fields (since Tschudi/NSIDC made it by particle tracking) but it may only surface in some dry static journal figure rather than a dynamic format.

great find  ;)

Wipneus

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Re: Latest PIOMAS update (February)
« Reply #1297 on: February 04, 2017, 08:47:42 AM »
PIOMAS updated, so I updated my graphics as well, see the top post

No surprise, PIOMAS confirms that the ice growth is dramatically less than in previous winters. I attach the yearly volume graph, and the yearly volume anomaly graphs.

Gridded thickness data is available as well, maps will be posted later.
« Last Edit: February 04, 2017, 08:53:05 AM by Wipneus »

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Re: Latest PIOMAS update (February)
« Reply #1298 on: February 04, 2017, 10:40:10 AM »
Insane...

Not you, Wipneus, I mean PIOMAS.  ;)
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Re: Latest PIOMAS update (February)
« Reply #1299 on: February 04, 2017, 10:57:48 AM »
Climatlogist Brian Brettschneider tweets that there is "Open water just northeast of Pt. Barrow and near Pt Hope - in February"

And from Zack Labes tweet at [url]https://twitter.com/ZLabe/status/827723158278922241]


And from Zack Labes tweet at https://twitter.com/ZLabe/status/827723158278922241 he says we are more than 1100 km3 below the previous record low January.

And finally, the sea ice thickness graph from PIOMAS shows how way off we are so far. And only about 1½ month until maximum should occur.