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Author Topic: Latest PIOMAS update (February update)  (Read 683632 times)

miki

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Re: Latest PIOMAS update (January update)
« Reply #2250 on: January 06, 2018, 06:50:14 AM »
I've posted the latest PIOMAS update on the ASIB, including stuff about CryoSat and the situation wrt temps and snow cover: PIOMAS January 2018.

Thanks so much, Neven. Excellent summary, as usual.

A-Team

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Re: Latest PIOMAS update (January update)
« Reply #2251 on: January 09, 2018, 05:09:18 PM »
wip: thickness animation for the last month. It seems you need to click, even with size less than 700x700, for the animation to start.
I tested sizes on a tiny 3-frame animation over at DevCorner. It seems 601 width and above will not animate properly any more. 600 animates irregularly. 599 and below animate as before.

Note these slightly larger animation still load fully and take up exactly the same amount of server storage space, they just need a click-tab to get going. They do not record visitor view counts otherwise.

There was an admin setting shown once upon a time where the 700x700 was displayed as the choice. Maybe Neven changed that? Or it got defaulted down to 600x600 in the course of other admin changes?

https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138340.html#msg138340

Neven

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Re: Latest PIOMAS update (January update)
« Reply #2252 on: January 09, 2018, 11:34:08 PM »
There was an admin setting shown once upon a time where the 700x700 was displayed as the choice. Maybe Neven changed that?

Maybe he did. Just to be sure he changed it back to 700x700.
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jdallen

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Re: Latest PIOMAS update (January update)
« Reply #2253 on: January 16, 2018, 05:44:23 AM »
Having a mad thought (tm) about ice thickness calculations/estimation, as I ponder ways to track heat transfer through the arctic..  It ties back to a few questions.  Bear with me, this may be redundant.

(1) Is snow depth on ice something which can be easily derived?  Are there gridded data sets which are able to provide that based on some sort of reasonably reliable sensor?

(2) Can we reasonably derive the ice/snow surface temperature either through estimated 2M temperatures?

(3) Alternatively, how good is the gridded temperature as derived from observed upwelling IR?

(4) Under the ice, can we reasonably assume the ice-water interface temp to be -1.8C?

It follows by this that we may be able to proxy ice thickness by comparing the heat flow as indicated by the observed temperature of the snow surface and subtracting out estimated flow through the snow using an average thermal transfer value, and then plugging that into an inverted equation for heat flow through ice, solving instead for thickness.

Anyone aware of research/modelling utilizing something like this strategy?  I'd rather not re-invent the wheel here.

I may want to start a separate thread for this, but I wanted to plant a seed here first.
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Neven

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Re: Latest PIOMAS update (January update)
« Reply #2254 on: January 16, 2018, 10:13:59 AM »
(1) Is snow depth on ice something which can be easily derived?  Are there gridded data sets which are able to provide that based on some sort of reasonably reliable sensor?

If only!  :(
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Michael

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Re: Latest PIOMAS update (January update)
« Reply #2255 on: January 16, 2018, 10:45:44 AM »
(1) Is snow depth on ice something which can be easily derived?  Are there gridded data sets which are able to provide that based on some sort of reasonably reliable sensor?
The the usual approach is to use climatology based on Warren 1999, modified to to allow for the increase in FYI.
http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%281999%29012%3C1814%3ASDOASI%3E2.0.CO%3B2

Lord M Vader

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Re: Latest PIOMAS update (January update)
« Reply #2256 on: January 31, 2018, 08:46:34 AM »
Seems like the mid-January update was cancelled. Anyone who know why? Looking forward to the February update soon! :)

Wipneus

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Re: Latest PIOMAS update (February update)
« Reply #2257 on: February 03, 2018, 01:58:20 PM »
Gridded PIOMAS model data has been updated. The "official" volume data and graphs not yet, as far as I can tell.

Estimated from the thickness data, the latest value is from 31st of January: 17.57 [1000 km3], which is the second lowest value for that day, 2017 is lowest by a rather large margin at 16.16   [1000 km3].

Attached the animation for January.

Wipneus

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Re: Latest PIOMAS update (February update)
« Reply #2258 on: February 03, 2018, 02:19:48 PM »
Thickness map on 31st Jan 2018, compared with previous years.

Wipneus

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Re: Latest PIOMAS update (February update)
« Reply #2259 on: February 03, 2018, 04:44:45 PM »
2018 versions of volume and volume-anomaly graphs.

Wipneus

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Re: Latest PIOMAS update (February update)
« Reply #2260 on: February 03, 2018, 05:53:31 PM »
Fram export graph updated.


oren

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Re: Latest PIOMAS update (February update)
« Reply #2262 on: February 03, 2018, 07:12:17 PM »
Thanks Wipneus. It seems 2018 is already headed into trouble.

A-Team

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Re: Latest PIOMAS update (February update)
« Reply #2263 on: February 03, 2018, 08:20:17 PM »
Export volume (area under the curve relative to 4 million possible) gives 0.8 million cu km exported for Oct, Nov, Dec, Jan.

The last 8 years of Fram export for these months are shown in the simulcast below:

Pavel

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Re: Latest PIOMAS update (February update)
« Reply #2264 on: February 04, 2018, 12:04:47 PM »
Thanks for the update. This year we have the stronger ice along the Siberian coast than last year. But we remember the 2017 snowy June and late melt ponds formation in the Laptev sea fast ice. I'm curious to see what we'll have this year

Richard Rathbone

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Re: Latest PIOMAS update (February update)
« Reply #2265 on: February 04, 2018, 02:11:39 PM »
Looks like the biggest pile up against Siberia for over a decade. If that persists through the maximum some of that ice might make it through the summer, but there will be big holes on the other side.

Jim Hunt

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Re: Latest PIOMAS update (February update)
« Reply #2266 on: February 04, 2018, 06:15:39 PM »
Looks like the biggest pile up against Siberia for over a decade.

CryoSat-2's version of events. 2014 looks to have been the worst in their records, but that's later in the season. I'll check my records to see if I have something more directly comparable.
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Blizzard92

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Re: Latest PIOMAS update (February update)
« Reply #2267 on: February 06, 2018, 09:57:59 PM »
UC Irvine - Earth System Science Ph.D. Candidate
Cornell University - Atmospheric Sciences B.Sc.

Twitter: @ZLabe
Website: http://sites.uci.edu/zlabe/

A-Team

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Re: Latest PIOMAS update (February update)
« Reply #2268 on: February 07, 2018, 10:47:14 PM »
CryoSat-2's version of events
Ascat's version of events, for the 124 days between 30 Sep 17 to 31 Jan 18. Here four of wipneus' monthly summary animations are butted end to end, then side by side with the same days of Ascat ice backscatter of C-band radar (roughly sea ice age, very roughly thickness). An awful lot of structural details are missing from Piomas.

The static png compares Jan 31st for the three sources. Cryosat has been rotated 45º ccw to match the Greenland down orientation of the other two. Blizzard92's has been rotated 45º cw. The Topaz product shown @seaice_de is so not readily re-oriented.

However here's a very nice animation comparing SMOS and Piomas in January from 2011-18.

http://www.seaice.de/PIOMAS_SMOS_Jan_2018.gif

« Last Edit: February 08, 2018, 08:47:13 PM by A-Team »

Neven

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Re: Latest PIOMAS update (February update)
« Reply #2269 on: February 07, 2018, 11:05:17 PM »
PIOMAS February 2018 is up on the ASIB.
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gerontocrat

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Re: Latest PIOMAS update (February update)
« Reply #2270 on: February 07, 2018, 11:32:53 PM »
PIOMAS February 2018 is up on the ASIB.
Thanks Neven, for the monthly fix. With no mid-month update I was having violent PIOMAS withdrawal symptoms.

ps: On the Northern Hemisphere Snow thread you have started, I posted graphs from Environment Canada -Snow Water Equivalent well up (though extent not so much).
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oren

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Re: Latest PIOMAS update (February update)
« Reply #2271 on: February 08, 2018, 01:53:50 AM »
Thanks Neven. An interesting read as usual.

jdallen

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Re: Latest PIOMAS update (February update)
« Reply #2272 on: February 08, 2018, 07:22:13 AM »
PIOMAS February 2018 is up on the ASIB.
Succinct as usual.

Regarding snow cover - it won't help much on the Atlantic side if the huge areas in the Barentsz and around FJL remain open through the rest of the refreeze and begin immediately taking up insulation weeks early which previously got bounced back out of the atmosphere.

If the storms continue, that snow and thinner ice will be more vulnerable to rainfall events. That buffer provided by snow cover could vanish in hours.

We are once again hoping we don't get a bad dice roll.
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A-Team

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Re: Latest PIOMAS update (February update)
« Reply #2273 on: February 08, 2018, 09:17:52 PM »
SMOS ice thinness classes of >0.3m, >0.6m, >1.0m compare rather well to Piomas monthly averages for January for the last nine years, downsized to the forum from https://twitter.com/seaice_de and presented there at a much larger scale:

http://www.seaice.de/PIOMAS_SMOS_Jan_2018.gif

However differencing the Jan 2018's tells a somewhat different story. Here the scale is too small for the Arctic Ocean proper (the rest melts out so who cares), especially since the interest is on the ice pack periphery. SMOS of course is available in netCDF but I've not seen Piomas in standard format. Panoply could do the quantitative subtractive display if both were there.

The key really is percent difference. If ice 0.5 m thick is off by 0.1 m, that is already 20%. How do we follow subtle trends in ice volume year-ion-year in this environment? And what does average thickness even mean when the ice can be moving by at 45 km a day, across a couple of grid cells: what ice are we talking about after a month of this? In the Beaufort, we have a 1000 km stringer of sparse 3 m floes sprinkled in amongst late FYI. What should be monitored in this situation?

Most eyes will be on the Beaufort this coming melt season. It looks especially weak in SMOS with the difference with Piomas seeming significant. The Chukchi is a lost cause, the Kara will melt out as it always does, and the Barents Edge will retreat early as its periphery is largely extruded immature ice from the Kara.

Technical note: Radial coordinates can be unwrapped but the AO is so lopsided with respect to latitude that the little gained by discarding unused interior to better compare peripheries would be offset by the confusion engendered.
« Last Edit: February 09, 2018, 12:43:05 AM by A-Team »