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jdallen

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Re: The 2023 melting season
« Reply #200 on: May 14, 2023, 10:24:23 AM »
I don’t remember observing during these past ten years or so such a swift decline of snow cover in Northern Canada and reaching so far North in May. Back in April snow cover in NA was anomalously large.

On the other hand, snow melting in Eurasia remains fairly average, which is actually an abnormal occurrence compared to the last years, when positive temperature anomalies in Siberia accelerated snow melt.
Watch for serious increases in the melt pond fraction in the Western  half of the Arctic.
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Niall Dollard

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Re: The 2023 melting season
« Reply #201 on: May 14, 2023, 11:11:17 PM »
DMI's 80N mean (complete with new colour plot and celsius scale) took a bit of a dip recently.

Looking back through previous years, a dip in May is quite common. e.g. in 2015 and 2013

Oddly there are some discontinuities showing on the graphs, for some reason.

gerontocrat

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Re: The 2023 melting season
« Reply #202 on: May 14, 2023, 11:44:26 PM »
DMI's 80N mean (complete with new colour plot and celsius scale) took a bit of a dip recently.

Looking back through previous years, a dip in May is quite common. e.g. in 2015 and 2013

Oddly there are some discontinuities showing on the graphs, for some reason.
DMI has been having some data problems - not for the first time. We might see the discontinuities magically disappear some time later.
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nadir

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Re: The 2023 melting season
« Reply #203 on: May 15, 2023, 03:43:11 AM »
While the Arctic itself remains relatively cool, especially around the North Pole, look at the record-smashing temperatures at these locations of the North of Canada.

Rodius

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Re: The 2023 melting season
« Reply #204 on: May 15, 2023, 04:05:36 AM »
While the Arctic itself remains relatively cool, especially around the North Pole, look at the record-smashing temperatures at these locations of the North of Canada.

Is that because the heat toward the tropics is attempting to reach the Arctic but is being blocked by wind?

peterlvmeng

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Re: The 2023 melting season
« Reply #205 on: May 15, 2023, 04:53:49 AM »
If you look at the global sst anomaly chart. It is interesting to see that the heat dome is so powerful in Canada even raising the sea surface temperature dramatically near the west coast from negative to positive anomaly. The heat dome definitely will promote the melt ponds in north Canada. Will the heat dome influence the development of ENSO?

Jim Hunt

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Re: The 2023 melting season
« Reply #206 on: May 15, 2023, 01:03:26 PM »
A quick scroll through Worldview suggests that 2016 was the last year in which melt ponds formed so early in the CAA.

However this year's Mackenzie River flow is a few days behind 2016:
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Comradez

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Re: The 2023 melting season
« Reply #207 on: May 15, 2023, 06:14:16 PM »
I've noticed on EOSDIS imagery a lot of wildfires breaking out in Western Canada recently.  It seems early in the season for that, no?  Also, to what extent will all of that smoke impede the warming up and melt, and partially compensate for the low snowcover over Canada currently?

HapHazard

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Re: The 2023 melting season
« Reply #208 on: May 15, 2023, 08:31:21 PM »
A bit early, but it's not uncommon to have fires in Alberta in May. However, we are in uncharted territory right now, in how quickly fire season has hit & in the sheer number & conditions. Alberta has declared a provincial state of emergency.


https://www.alberta.ca/alberta-wildfire.aspx

https://www.cbc.ca/news/canada/edmonton/alberta-wildfires-province-military-recovery-canada-1.6843182
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jdallen

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Re: The 2023 melting season
« Reply #209 on: May 15, 2023, 09:52:17 PM »
While the Arctic itself remains relatively cool, especially around the North Pole, look at the record-smashing temperatures at these locations of the North of Canada.
So much for any remaining North American snow cover.
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jdallen

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Re: The 2023 melting season
« Reply #210 on: May 15, 2023, 09:54:26 PM »
<snip> The heat dome definitely will promote the melt ponds in north Canada. Will the heat dome influence the development of ENSO?
Actually, I suspect the heat dome is a ->consequence<- of the ENSO shift, as northern hemisphere circulation is affected.
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Michael Hauber

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Re: The 2023 melting season
« Reply #211 on: May 15, 2023, 10:37:30 PM »
Last few months have seen high pressure over Canadian/Greenland side, and low pressure over Russia and good part of Arctic.  Dipole like and boosting Fram export and general transport of ice from Pacific side to Atlantic side.  Pattern currently changing to low pressure over Greenland side and central pole region, although still higher pressure towards Alaska.  This is the same pattern as slowed down the 2021 melt season promoting general transport towards Pacific side.  If pattern maintains will be slow start to the melt season proper but high pressure is pushing from Pacific side and might disrupt it.
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nadir

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Re: The 2023 melting season
« Reply #212 on: May 16, 2023, 12:46:47 AM »
Last few months have seen high pressure over Canadian/Greenland side, and low pressure over Russia and good part of Arctic.  Dipole like and boosting Fram export and general transport of ice from Pacific side to Atlantic side.  Pattern currently changing to low pressure over Greenland side and central pole region, although still higher pressure towards Alaska.  This is the same pattern as slowed down the 2021 melt season promoting general transport towards Pacific side.  If pattern maintains will be slow start to the melt season proper but high pressure is pushing from Pacific side and might disrupt it.

It’s already been a slow start IMO, but I think the heat over Canada is unprecedented and may lead to unprecedented effects.

The next interesting development is surface melt over Beaufort/Chukchi/ESS. Then we’ll see.

Jim Hunt

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Re: The 2023 melting season
« Reply #213 on: May 16, 2023, 01:34:17 AM »
The next interesting development is surface melt over Beaufort

Your wish is my command:

https://GreatWhiteCon.info/2023/05/facts-about-the-arctic-in-may-2023/#May-15
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jdallen

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Re: The 2023 melting season
« Reply #214 on: May 16, 2023, 01:36:13 AM »
Last few months have seen high <snip>... This is the same pattern as slowed down the 2021 melt season promoting general transport towards Pacific side.  If pattern maintains will be slow start to the melt season proper but high pressure is pushing from Pacific side and might disrupt it.

It’s already been a slow start IMO, but I think the heat over Canada is unprecedented and may lead to unprecedented effects.

The next interesting development is surface melt over Beaufort/Chukchi/ESS. Then we’ll see.

Even severe heat will have limited direct effect on the ice.

Key ways the heat dome may affect the the ice are (1) rapid development and expansion of melt ponds and (2) maintaining clear weather over the affected pack, increasing insolation update.

The direct application of heat to the ice by comparison will be trivial.
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jdallen

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Re: The 2023 melting season
« Reply #215 on: May 16, 2023, 02:36:45 AM »
The next interesting development is surface melt over Beaufort

Your wish is my command:

https://GreatWhiteCon.info/2023/05/facts-about-the-arctic-in-may-2023/#May-15
I assume Corrected Reflectance bands 7-2-1 on Worldview?  Tends to show surface melt pretty well when there isn't a lot of cloud cover.

(edit:)  I expect to see significant melt pond formation in the coastal (within 300KM or so)  Beaufort, Chukchi and inner/southern CAA over the next 10 days with similar in the western Kara.
I expect ice in the Bering and Okhotsk to mostly disappear entirely in the same time frame.

None of these are unusual alone in and of themselves, but could signal increased melt momentum.
« Last Edit: May 16, 2023, 02:54:09 AM by jdallen »
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binntho

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Re: The 2023 melting season
« Reply #216 on: May 16, 2023, 10:19:59 AM »
Even severe heat will have limited direct effect on the ice.

Key ways the heat dome may affect the the ice are (1) rapid development and expansion of melt ponds and (2) maintaining clear weather over the affected pack, increasing insolation update.

The direct application of heat to the ice by comparison will be trivial.
The melt ponds are very important as they change the albedo of the ice significantly and enable radiation to penetrate deeper, kicking off bottom melt.
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jdallen

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Re: The 2023 melting season
« Reply #217 on: May 16, 2023, 10:29:44 AM »
Even severe heat will have limited direct effect on the ice.

Key ways the heat dome may affect the the ice are (1) rapid development and expansion of melt ponds and (2) maintaining clear weather over the affected pack, increasing insolation update.

The direct application of heat to the ice by comparison will be trivial.
The melt ponds are very important as they change the albedo of the ice significantly and enable radiation to penetrate deeper, kicking off bottom melt.
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Jim Hunt

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Re: The 2023 melting season
« Reply #218 on: May 16, 2023, 10:34:52 AM »
I assume Corrected Reflectance bands 7-2-1 on Worldview?

Correct!

Meanwhile in Tuk:
« Last Edit: May 16, 2023, 11:00:37 AM by Jim Hunt »
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oren

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Re: The 2023 melting season
« Reply #219 on: May 16, 2023, 12:05:22 PM »
Large parts of the CAA appear quite toasty, relatively speaking.

Freegrass

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Re: The 2023 melting season
« Reply #220 on: May 16, 2023, 05:24:24 PM »
Latest Five Day Forecast + Last 5 Days
Wind + Temp @ Surface
And 30 day HYCOM
Large GiFs!
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Glen Koehler

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Re: The 2023 melting season
« Reply #221 on: May 16, 2023, 07:47:10 PM »
     Thanks for the HYCOM thickness animations Freegrass.  At risk of revealing myself as a Nares Strait fanboy, I see it actively sucking down some of the reddest thickest ice from the heart of the so-called "Last ice" area.  And letting my catastrophist spirits run free, I also see what could be "garlic press" movement of thick ice along the eastern coast of Banks Island into the CAA.  And farther to the east in the middle of the CAA - CAB boundary, some suspicious southward sagging of the thick ice line between Borden Island and Ellef Ringnes Island. 

     The current warming of the CAA could be consequential if it opens up new export gates from the CAB into the CAA, especially given that open doors along that boundary would expose the thin band of the thickest MYI ice to being moved south into a sure-fire melt zone.  The southern end of the CAA already looks like an active drain field.  As goes the CAA, so goes the ASI.
« Last Edit: May 16, 2023, 08:01:51 PM by Glen Koehler »
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Freegrass

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Re: The 2023 melting season
« Reply #222 on: May 16, 2023, 08:56:23 PM »
You're welcome Glen, but I wouldn't put too much faith in HYCOM when it comes to coastlines and the CAA. HYCOM is very bad at that. Uniquorn posted a paper on that in the HYCOM thread a while ago, but I'm not sure if they intend to correct HYCOM. Maybe someone can help me to figure this out? It sure would be good if HYCOM could get better at that.
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FishOutofWater

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Re: The 2023 melting season
« Reply #223 on: May 16, 2023, 09:39:37 PM »
These subsidence highs create ideal conditions for melting when the sun is relatively high in the sky as it is now. Shallow inversions form above the snow and ice heat that is taken up in that layer stays in that layer as the ice melts. Very little radiates back out to space because it stays cold in the inversion layer. When there's a melt pond, much of the energy goes into the water below the ice.

The impacts of early melt ponds in the CAA will be very interesting to watch.

Meanwhile, on the other side of the Arctic a huge subsidence high is beginning to become established over Scandinavia. Strong southerly winds from the north Atlantic and storms moving into the Arctic will cause a strong push back of the snow pack and the ice in the Barents and Kara seas.

Yes, this is the opposite of the 2007 dipole set up and sea ice extent is presently above recent decadal averages, but there will be strong melting and strong loss of albedo feed backs.

This summer won't be like 2007. SST and ocean heat patterns are more like 2006 or 2012 now.  The ocean heat content of the north Atlantic is very, very high now, especially on the eastern half.

Paul

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Re: The 2023 melting season
« Reply #224 on: May 17, 2023, 01:18:58 AM »
Meanwhile, on the other side of the Arctic a huge subsidence high is beginning to become established over Scandinavia. Strong southerly winds from the north Atlantic and storms moving into the Arctic will cause a strong push back of the snow pack and the ice in the Barents and Kara seas.

This is definitely the most interest aspect of the forecasts I'm seeing. The Kara sea looks like it's going to be hit by winds and warm air as soon as in  12-24 hours time although it looks like things will turn a bit cooler again however more widely perhaps as we head into the medium term is a period of southerly winds hitting the barants sea ice. Nothing exceptional but will be interesting how the ice responds to it.

The DMI temperature for what's it's worth is quite interesting at the moment, you could not get a contrasting set up to what we saw in 2020 in both temperature and air pressure but I'm not sure I would like too see this low continuing for too much longer otherwise we may start too see a repeat of the dispersion we saw in the ice last year. It was just fortunate the ice edge never reached the diffused area from the Atlantic side otherwise things may of got interesting.

After the first "warmth" for the Beaufort things are turning colder here and it looks like the CAA and Hudson Bay will be turning colder again so I'm not too convinced the early heat will have impacts later on in the melt season unless we see a real sustained period of high temperatures during the summer.

Brigantine

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Re: The 2023 melting season
« Reply #225 on: May 17, 2023, 01:31:41 AM »
The beginnings of (SMOS) surface wetness are showing in the Chukchi/Beaufort/CAB border area.


- Also Cambridge Bay, Hudson Bay, E Greenland sea and part of Laptev seem IMO to show surface melt
- Some other places with non-beige pixels are for now IMO better explained by thin ice in wind-driven polynyas
- The northern Barents /western Kara I won't guess whether it's surface wetness, ice thinness, or dispersion

P.S. standard disclaimer about not representing "ice thickness" in summer. Interpret the scale as wet <----> dry

Aluminium

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Re: The 2023 melting season
« Reply #226 on: May 17, 2023, 06:45:26 AM »
May 11-16.

2022.

Niall Dollard

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Re: The 2023 melting season
« Reply #227 on: May 17, 2023, 07:37:09 AM »
Thanks Aluminium. Good to see these charts again.

Freegrass

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Re: The 2023 melting season
« Reply #228 on: May 17, 2023, 11:25:27 AM »
May 11-16.

2022.
Good to have you back Aluminium!
Happy days...  :)
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Jim Hunt

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Re: The 2023 melting season
« Reply #229 on: May 17, 2023, 02:56:05 PM »
The Mackenzie River flow is suddenly off the charts.

It remains to be seen what the data looks like in a few years time after it's eventually been "reanalysed", but here is the (extremely!) preliminary version:
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Re: The 2023 melting season
« Reply #230 on: May 17, 2023, 07:55:41 PM »
The Mackenzie River flow is suddenly off the charts.

It remains to be seen what the data looks like in a few years time after it's eventually been "reanalysed", but here is the (extremely!) preliminary version:

This looks like a data anomaly, doesn't it? If it isn't then we've missed something big.
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HapHazard

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Re: The 2023 melting season
« Reply #231 on: May 17, 2023, 09:40:41 PM »
RE: Mackenzie talk above ^

https://www.cbc.ca/news/canada/north/fort-mcpherson-n-w-t-on-flood-watch-as-peel-river-rises-1.6844863





Fort MacPherson is located on the Peel River, near it's confluence with the Mackenzie. Lovely area, I hope to get back there soon.
« Last Edit: May 17, 2023, 09:45:46 PM by HapHazard »
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Renerpho

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Re: The 2023 melting season
« Reply #232 on: May 17, 2023, 10:27:58 PM »
I hope to get back there soon.

If you return there within the next 48 hours, maybe you can tell us what's going on.  ::)

On a more serious note, how unusual is flooding like what's reported there? Unusual enough to suggest that the spike is real?
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HapHazard

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Re: The 2023 melting season
« Reply #233 on: May 17, 2023, 10:52:25 PM »
If I started driving now, I could reach the (now useless) ferry just south of there in 3 days, so hang on!

Seems it's largely an ice jam, but it's much more severe than normal. I'm not sure, and a bit busy to check around at the moment. But I imagine when it finally lets go, there will be a pretty large pulse of melt water released down the Mackenzie.
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Jim Hunt

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Re: The 2023 melting season
« Reply #234 on: May 18, 2023, 12:22:00 AM »
This looks like a data anomaly, doesn't it? If it isn't then we've missed something big.

There are often erroneous gaps and/or spikes in the data during breakup. Here's the disclaimer:

https://wateroffice.ec.gc.ca/ice_conditions_e.html

However other gauges show something similar. The middle channel nearer the sea was also off the (previous) charts before the gauge gave up:
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oren

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Re: The 2023 melting season
« Reply #235 on: May 18, 2023, 01:17:12 AM »
Interesting, thanks for the updates.
It appears the recent warmth in Canada had at least one consequence.

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Re: The 2023 melting season
« Reply #236 on: May 18, 2023, 02:13:47 AM »
Quote
A large ice jam had been occupying the Mackenzie River between Norman Wells and Fort Good Hope
The water level should be real.
Though perhaps the flow rate is not correspondingly high, as the ice jam explains some of the water level?

Jim Hunt

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Re: The 2023 melting season
« Reply #237 on: May 18, 2023, 11:30:56 AM »
The water level should be real.

The gauge above Fort McPherson seems to be working again, and suggests that the Peel River water level is now slowly reducing:
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A-Team

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Re: The 2023 melting season
« Reply #238 on: May 18, 2023, 03:56:02 PM »
Quote
once thickness gets below 1 m the effects of faster melting rate/less melt resistance, less structural ice pack integrity, increasingly warm summers and winters, lower ice concentration will allow a rapid increase in export. A "great ASI flush" could exceed the 10-year great MYI decline. - Glen K
Would we even recognize a tipping point if we saw one? Rather unusual ice pack motion so far for 2023 as seen with Ascats at ten day intervals.

Much discussion of fitting trend lines to time series of numbers. Can we do that as well for the next couple of frames of an animation?

Jim Hunt

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Re: The 2023 melting season
« Reply #239 on: May 18, 2023, 04:29:51 PM »
Rather unusual ice pack motion so far for 2023 as seen with Ascats at ten day intervals.

As I idly wondered a couple of months ago:

Quote
How long do you suppose it will take for all the extra ice currently heading south past the east coast of Greenland to melt?
« Last Edit: May 18, 2023, 09:10:58 PM by Jim Hunt »
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Re: The 2023 melting season
« Reply #240 on: May 18, 2023, 05:21:43 PM »
Much discussion of fitting trend lines to time series of numbers. Can we do that as well for the next couple of frames of an animation?

This might be a starting point:

https://www.researchgate.net/publication/365635579_Intermediate_and_Future_Frame_Prediction_of_Geostationary_Satellite_Imagery_With_Warp_and_Refine_Network
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Re: The 2023 melting season
« Reply #241 on: May 18, 2023, 09:05:48 PM »
Are the deep blue areas along the CAA coast melt ponds? (Circled in red.) I'm not totally sure how to interpret these.

May 15 Worldview, Aqua/MODIS corrected reflectance bands 7-2-1.

Jim Hunt

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Re: The 2023 melting season
« Reply #242 on: May 18, 2023, 09:13:20 PM »
Are the deep blue areas along the CAA coast melt ponds?

Yes. IMHO!

https://forum.arctic-sea-ice.net/index.php/topic,3941.msg367171.html#msg367171

See also the Kara coast today.

P.S. And Greenland. I'm not sure what those darker blue areas represent, but it seems unlikely to be melt ponds.
« Last Edit: May 18, 2023, 09:52:52 PM by Jim Hunt »
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Re: The 2023 melting season
« Reply #243 on: May 18, 2023, 09:56:22 PM »
Thx for the link! (Also at https://arxiv.org/abs/2303.04405)

The authors put forth innovative ideas like dividing the future frame problem into an optical flow warp and a warped image refinement components. Training the deep-learning model on a human-centric view of the RGB channel is an attractive concept. As they note, that doesn't work with grayscale instruments such as Ascat.

Meanwhile OsiSaf offers us two-day gridded ice displacement vectors. Thus a pixel at coordinate m,n moves to p,q forcing narrow quantization of both angle and distance. So the future frame - in the least imaginative approach Newton's 1st for a rigid pack - just double downs on that for p,q moving to r,s.

On a consistently windy week, for a 500x400 pixel depiction of the Arctic Ocean (eg at Ascat's resolution), a feature's net change in position m-p,n-q might be something like 5 pixels over and 12 pixels down for a displacement of 13, so the same for the future frame.

Stephan recently dug into the numeric backside of OsiSaf in the course of estimating Fram export. Those numbers could be regridded graphically to the resolution of Ascat  as two floating layers that direct construction in a spreadsheet-like object of the warped future frame.

Since the ice rifts and rafts, not all the pixel are moving the same direction just in patches so many future frame pixels are superpositions. Future frame quality is easily tested by waiting a week and imaging subtracted pixel values ('grain extract' in Gimp).

Thus the shelf life of a future frame is very short. The main interest is proving a persistent trend: the imaged future frame error will be much smaller than during chaotic periods.

Below you can a sense of what the calculation needs to do with May 10 and May 17 to get at May 24 from the roughness of the third (differencing) pane.
« Last Edit: May 18, 2023, 10:04:58 PM by A-Team »

Freegrass

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Re: The 2023 melting season
« Reply #244 on: May 19, 2023, 02:55:58 AM »
Latest Five Day Forecast + Last 48h
Wind + Temp @ Surface
Large GiF!

Melt ponds should be showing up all over the place on the Pacific side now. We're definitely in the high arctic melting season now...
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jdallen

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Re: The 2023 melting season
« Reply #245 on: May 19, 2023, 05:16:30 AM »
Are the deep blue areas along the CAA coast melt ponds?

Yes. IMHO!

https://forum.arctic-sea-ice.net/index.php/topic,3941.msg367171.html#msg367171

See also the Kara coast today.

P.S. And Greenland. I'm not sure what those darker blue areas represent, but it seems unlikely to be melt ponds.
In the same vein, same filter, the Hudson from yesterday.  Most of that surface is covered by melt.  It should be mostly broken up by July.
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Re: The 2023 melting season
« Reply #246 on: May 19, 2023, 05:27:38 AM »
Quote
once thickness gets below 1 m the effects of faster melting rate/less melt resistance, less structural ice pack integrity, increasingly warm summers and winters, lower ice concentration will allow a rapid increase in export. A "great ASI flush" could exceed the 10-year great MYI decline. - Glen K
Would we even recognize a tipping point if we saw one? Rather unusual ice pack motion so far for 2023 as seen with Ascats at ten day intervals.

Much discussion of fitting trend lines to time series of numbers. Can we do that as well for the next couple of frames of an animation?

Nice to see you again A-Team.

Recognize?  Probably not, as I don't think it will be occuring in an easily recognizable time frame; that is, it probably won't be visible as a prompt event, but as a broader transition.

We may be seeing that, may not; it will be hard to sort until we get to the end point and can work our way back through events to see if we can link them up.

It *does* feel like there's a "death of a thousand cuts" taking place right now.  No single remarkable 2 or 3 sigma event, but rather an aggregate of moderate ones stacking up.

The Fram export is one of those - I don't recall seeing as long and proportionately high an outgoing flow as we've seen this winter and spring, nor the persistent circulatory setup.  Ice is no longer heading to the Beaufort, but rather joining a MYI rush to the exit heading east across the top of the CAA and Greenland.

As to fitting lines to curves for short time frame animations to make them predictive?  I think we're talking weather-model level number crunching of multiple factors.  Best test would be to run it against an earlier data set and see how it stacks up against the observed, of course, but I don't think we could derive it from just model output.
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Re: The 2023 melting season
« Reply #247 on: May 19, 2023, 11:09:28 AM »
GFS suggests that the basin will be occupied by a 977 hPa MSLP low tomorrow morning UTC.

It also confirms that the snow cover has departed from the dark blue areas visible on MODIS 7-2-1!
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Jim Hunt

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Re: The 2023 melting season
« Reply #248 on: May 19, 2023, 11:45:54 AM »
Bottom melt appears to have started in the western Beaufort Sea at 74.56 N, 155.4 EW!, the location of ice mass balance buoy 651330:
« Last Edit: May 20, 2023, 10:20:01 AM by Jim Hunt »
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Re: The 2023 melting season
« Reply #249 on: May 19, 2023, 12:55:34 PM »
Interesting. Still has 11cm snow and air temps dropped to -11C after the high of +3.1C.

According to Mercator 651330 is sitting over a warm eddy at 40m depth.
https://data.marine.copernicus.eu/-/n747la41su
« Last Edit: May 19, 2023, 01:03:43 PM by uniquorn »