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bbr2314

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Re: The 2018/2019 freezing season
« Reply #750 on: November 19, 2018, 01:26:29 AM »
Compare the earliest HB refreeze in recent years (2015) with 2018 and you can see how this year's momentum is finally showing. But it has been very obvious for a while. 2015 stalled fairly majorly after this point (and other years were not as close), the differential will finally become very noticeable within the next week.





2018 has ice ringing almost the entirety of HB and the snowcover this year has also been vastly more impressive. In fact, we are now well over +50% vs. normal SWE for North America.

Also: here is an update on current Great Lakes SSTs vs. last two years, looks like with all the crazy the past few weeks, drops have begun accelerating again.

Lake, vs 2017, vs 2016

Superior: -1.6F, -4.4F
Michigan: -2.2F, -5.3F
Huron: -2.0F, -4.7F
Erie: -3.2F, -6.8F
Ontario: -2.2F, -3.6F

oren

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Re: The 2018/2019 freezing season
« Reply #751 on: November 19, 2018, 01:28:36 AM »
bbr, if you have a point to make about HB and EOSDIS, why don't you post a comparison of EOSDIS images for 2018 vs. 2015, 2014, 2017, 2013? These are years where UH AMSR2 area data shows similar values. The best would be an animation. Instead of capitalizing messages and making sure to post the last word, you could try to actually prove your point.
Calling UH AMSR2 data "some random computer's output" on this forum is not going to cut it.

Shared Humanity

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Re: The 2018/2019 freezing season
« Reply #752 on: November 19, 2018, 01:28:48 AM »
The refreeze will be mostly done in a few days.

I'm guessing no based on this extent map. I guess we will know in a few days

bbr2314

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Re: The 2018/2019 freezing season
« Reply #753 on: November 19, 2018, 01:35:17 AM »
bbr, if you have a point to make about HB and EOSDIS, why don't you post a comparison of EOSDIS images for 2018 vs. 2015, 2014, 2017, 2013? These are years where UH AMSR2 area data shows similar values. The best would be an animation. Instead of capitalizing messages and making sure to post the last word, you could try to actually prove your point.
Calling UH AMSR2 data "some random computer's output" on this forum is not going to cut it.
Go here and swap out the year for the year you want to compare with for a uniform and easy way to gauge comparisons between years: (link may say unsecure) I would do a GIF but they save as .gifs so screenshotting etc is too much work.

https://www.natice.noaa.gov/pub/ims/ims_v3/ims_gif/ARCHIVE/USA/2018/ims2018322_usa.gif

It is clear (browsing back through the end) that the only comparable recent years are 2015 and 2017 also comes close. As mentioned, 2015 lost momentum following the early surge, and 2017 also saw a pause. I do not think we see a pause this year as momentum has been building for much longer and per the EURO, SSTs are much colder than 2017.

Also: we now have the first ice on both Huron and Superior! Very little, but still an early start.



« Last Edit: November 19, 2018, 01:41:06 AM by bbr2314 »

litesong

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Re: The 2018/2019 freezing season
« Reply #754 on: November 19, 2018, 02:15:45 AM »
Can’t be sure what’s driving this since temps in arctic are not below average.
Much of the over-heating in the Arctic & High Arctic, usually comes from temperate & even tropical lower latitudes, during this time of complete Arctic darkness. Presently however, cold that has been in almost all of fall Canada, dipping at times into the U.S., strengthened a week or two ago. Parts of the mid U.S., at times, were 20degC below average, with some cold dipping into Mexico. Also, the Canadian cold pushed into the Arctic & even to the High Arctic. The High Arctic for the past two months, being as high as 10degC over normal, has not only dropped precipitously in degC, but even fell further, as much as 7degC below anomalous high levels, during this period of fall complete Arctic darkness. 
« Last Edit: November 20, 2018, 11:00:21 PM by litesong »

HapHazard

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Re: The 2018/2019 freezing season
« Reply #755 on: November 19, 2018, 03:29:52 AM »
It's been "in a few days" for a few weeks now.  ;) (please stop quoting people who are on my blocklist, folks!)
« Last Edit: November 19, 2018, 04:35:35 AM by HapHazard »

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Re: The 2018/2019 freezing season
« Reply #756 on: November 19, 2018, 07:08:23 AM »
GFS has the temperature anomalies in NH and world rising quickly through the rest of November. Not sure what that means if anything for the freeze up, being new here, but it seems relevant given bbr's claims.
« Last Edit: November 19, 2018, 07:50:23 AM by wdmn »

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Re: The 2018/2019 freezing season
« Reply #757 on: November 19, 2018, 09:46:29 AM »
Aluminium, is it not possible to make it a little bit bigger ? So that we can see what happens east end west of greenland .
I don't want to change area. Any area may be a little bit bigger. Current size is convenient for me and includes main part of the Arctic Ocean.

November 14-18.

uniquorn

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Re: The 2018/2019 freezing season
« Reply #758 on: November 19, 2018, 10:22:08 AM »
amsr2-uhh, husdon bay, foxe basin, nov10-18
edit: added worldview-hudson-nov19
« Last Edit: November 19, 2018, 10:34:56 AM by uniquorn »

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Re: The 2018/2019 freezing season
« Reply #759 on: November 19, 2018, 11:54:12 AM »
The freezing season is very strong of late. After falling to lowest ever 2018 is now in 11th place, exceeding every year since 2006 in ice extent except 2008 and 2014. Can’t be sure what’s driving this since temps in arctic are not below average.

I was wondering about the exact same thing. could it maybe have something to do with the Mpemba effect (warmer water freezes quicker than cold water) ?

https://arxiv.org/ftp/arxiv/papers/1310/1310.6514.pdf


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Re: The 2018/2019 freezing season
« Reply #760 on: November 19, 2018, 12:31:09 PM »
I am sure Hudson Bay will freeze up quickly over the next few days, and ice area will be well above the 2010's average and probably the 2000's average as well.

But, GFS, wunderground.com etc predict a significant weather change as warmth spreads West to East across N. America (but not the extreme NE). By Friday /Saturday extreme cold will have lessened greatly in much of Central Canada including south of Foxe Basin. This could slow freezing of the southern half  of Hudson Bay considerably.

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Re: The 2018/2019 freezing season
« Reply #761 on: November 19, 2018, 01:21:13 PM »
The freezing season is very strong of late. After falling to lowest ever 2018 is now in 11th place, exceeding every year since 2006 in ice extent except 2008 and 2014. Can’t be sure what’s driving this since temps in arctic are not below average.

I was wondering about the exact same thing. could it maybe have something to do with the Mpemba effect (warmer water freezes quicker than cold water) ?

https://arxiv.org/ftp/arxiv/papers/1310/1310.6514.pdf

I think the Mpemba effect was discredited recently and can be explained through measurement error. With regards to the freezing season 'above average' may be a bit misleading in a rapidly warming arctic. Was it above average with respect to more recent years? And I suppose even if it was as long as the peripheries are colder than normal we can still have a faster than normal freezing season.

litesong

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Re: The 2018/2019 freezing season
« Reply #762 on: November 19, 2018, 06:06:01 PM »
In only a few days, the gap between 2016 & 2018 ripped wider by 4/10ths of a million square kilometers to a total difference of 1.2 million square kilometers. As wide a gap as this most recent diversion from each other is, it can be expected that even wider 2016-2018 splits in sea ice quantities will occur in the next days ahead.
As expected, in 1 day the 2016-2018 sea ice extent gap ripped open further, now to almost 1.5 million square kilometers. Most of the sea ice gap ripping was due to the present High Arctic & Arctic atmospheric chilling, funneling from Canada. However, the extreme to-date 2016 anomalous heating also caused sea ice extent LOSS, contributing to the wild splaying 2016-2018 sea ice extent separation. Should be more 2016-2018 sea ice extent widening coming.   

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Re: The 2018/2019 freezing season
« Reply #763 on: November 19, 2018, 07:20:58 PM »
Aluminium, thanks anyway. It's pretty amazing to see the Arctic change from day to day.

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Re: The 2018/2019 freezing season
« Reply #764 on: November 19, 2018, 09:06:50 PM »
Aluminium, is it not possible to make it a little bit bigger ? So that we can see what happens east end west of greenland .
I don't want to change area. Any area may be a little bit bigger. Current size is convenient for me and includes main part of the Arctic Ocean.

November 14-18.
No problem. I block you until June. Your now irrelevant half a mega is currently inconvenient for me when loading the page. Merry Christmas and happy 2019!

oren

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Re: The 2018/2019 freezing season
« Reply #765 on: November 19, 2018, 09:31:57 PM »
Just to put in a different opinion, I find Aluminium's animations still quite useful. I do note they are not posted daily anymore, but actually every two days which is better in the current season. The developments in the Chukchi and Barents/Kara/Svalbard regions are still relevant and informative.
Later on, it's best either to increase animation size to show the peripheral areas, or even better to quit posting these animations until changes return to the central regions. Or post them every 5-10 days.
During the main season these were the posts I most looked forward to, besides the area/extent numbers.
« Last Edit: November 20, 2018, 01:14:50 AM by oren »

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Re: The 2018/2019 freezing season
« Reply #766 on: November 19, 2018, 09:43:17 PM »
Just to put in a different opinion, I find Aluminium's animations still quite useful. I do not they are not posted daily anymore, but actually every two days which is better in the current season. The developments in the Chukchi and Barents/Kara/Svalbard regions are still relevant and informative.

Ditto. Thank, Aluminium.

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Re: The 2018/2019 freezing season
« Reply #767 on: November 19, 2018, 10:17:22 PM »
Or post them every 5-10 days.
It's highly likely. Changes in the central Arctic will be minimal but the Barents Sea and, possible, the Bering Strait still could be interesting in winter.

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Re: The 2018/2019 freezing season
« Reply #768 on: November 19, 2018, 11:12:24 PM »
I am sure Hudson Bay will freeze up quickly over the next few days,By Friday /Saturday extreme cold will have lessened greatly in much of Central Canada including south of Foxe Basin. This could slow freezing of the southern half  of Hudson Bay considerably.

my thoughts exactly hence sorry to share your property [Just Kidding]

in such cases it's at times good to look at temps instead of anomalies because anomalies of +20C in winter can mean -20C still cold enough for a full freeze but it's not the case here. it will be above zero over southern HB and everything what you already said +1

bbr2314

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Re: The 2018/2019 freezing season
« Reply #769 on: November 20, 2018, 12:27:22 AM »
I am sure Hudson Bay will freeze up quickly over the next few days,By Friday /Saturday extreme cold will have lessened greatly in much of Central Canada including south of Foxe Basin. This could slow freezing of the southern half  of Hudson Bay considerably.

my thoughts exactly hence sorry to share your property [Just Kidding]

in such cases it's at times good to look at temps instead of anomalies because anomalies of +20C in winter can mean -20C still cold enough for a full freeze but it's not the case here. it will be above zero over southern HB and everything what you already said +1
That is a 213 hour forecast map and the GFS has had a very warm bias over Hudson Bay in recent months. It does not have dynamic ice-atmospheric coupling so it remains with the starting ice #s for the duration of its run (that is to say, it still has 00z hr ice coverage by D10 in Hudson Bay, when that is most definitely inaccurate and likely wildly so).

uniquorn

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Re: The 2018/2019 freezing season
« Reply #770 on: November 20, 2018, 11:58:03 AM »
Or post them every 5-10 days.
It's highly likely. Changes in the central Arctic will be minimal but the Barents Sea and, possible, the Bering Strait still could be interesting in winter.
The Atlantic ice front and the Fram Strait are also quite interesting. :)

jdallen

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Re: The 2018/2019 freezing season
« Reply #771 on: November 20, 2018, 07:19:35 PM »
The freezing season is very strong of late. After falling to lowest ever 2018 is now in 11th place, exceeding every year since 2006 in ice extent except 2008 and 2014. Can’t be sure what’s driving this since temps in arctic are not below average.
Quick from the hip theory - less imported humidity from lower latitudes, thus less to impede outbound longwave radiation, *and* lower humidity would permit greater evaporation, which is a very local energy transfer directly from the water surface that would drop sea surface temperatures even with "warmer" atmosphere.

Here is the thing  though - relating to discussion on the area/extent thread - that exchange halts the moment the ice forms, and we change the primary transfer mechanism from primarily convective to primarily conductive.  The "R" value of ice is surprisingly high, and permits snow accumulation, which makes prospects worse for heat loss.

Collapse repeat something else I've said...  I think we are on the cusp of major deep system changes.  As we reach and start breaking the system symmetry, its overallbehavior will become more volatile, especially considering the huge increases in total energy available (see: pentajoule-scale increases in total oceanic enthalpy).

In short, the rapid ice return is not reassuring.  I may we rethink that if it happens 5 years running, but I don't think ill get that chance.
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gerontocrat

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Re: The 2018/2019 freezing season
« Reply #772 on: November 20, 2018, 08:25:08 PM »

That is a 213 hour forecast map

No it was not. More like 120 hrs in the future (from yesterday).

And here is a GFS map for Saturday Nov 24 - about 100 hrs from now. A blip in Hudson Bay freezing is possible. It also suggests some reduction in the extreme cold in NE Canada in the days after.
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bbr2314

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Re: The 2018/2019 freezing season
« Reply #773 on: November 20, 2018, 08:26:12 PM »

That is a 213 hour forecast map

No it was not. More like 120 hrs in the future (from yesterday).

And here is a GFS map for Saturday Nov 24 - about 100 hrs from now. A blip in Hudson Bay freezing is possible. It also suggests some reduction in the extreme cold in NE Canada in the days after.
It was 213 hours, it says so on the upper top, initialized 11/19 and forecast date: 11/28...

Literally pasting this here because I'm not wrong / it's ironic to see the people screaming about posts D5+ posting spot output for a certain hour with a model that has known biases that make it completely unreliable by that point for that specific region.


gerontocrat

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Re: The 2018/2019 freezing season
« Reply #774 on: November 20, 2018, 08:29:08 PM »

That is a 213 hour forecast map

No it was not. More like 120 hrs in the future (from yesterday).

And here is a GFS map for Saturday Nov 24 - about 100 hrs from now. A blip in Hudson Bay freezing is possible. It also suggests some reduction in the extreme cold in NE Canada in the days after.
It was 213 hours, it says so on the upper top, initialized 11/19 and forecast date: 11/28...

Literally pasting this here because I'm not wrong / it's ironic to see the people screaming about posts D5+ posting spot output for a certain hour with a model that has known biases that make it completely unreliable by that point for that specific region.
My map was not. One, I suppose, should be entirely specific to avoid such disputes.
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Brigantine

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Re: The 2018/2019 freezing season
« Reply #775 on: November 20, 2018, 10:40:21 PM »
The garlic press is now closed, according to the Russians. (but if Canada disagrees tomorrow, I'll follow them)

Svaalbard must be an eerie place at the moment - No light, (sun 6*+ below the horizon at all times) but at the same time no ice.

uniquorn

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Re: The 2018/2019 freezing season
« Reply #776 on: November 20, 2018, 11:41:05 PM »
Agreed. It looks like there is only movement in the Nares now.
Here is a comparison of 2017 and 2018, using amsr2-uhh, from oct1 to nov19. 2017 is outlined in green.

Ice Shieldz

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Re: The 2018/2019 freezing season
« Reply #777 on: November 21, 2018, 07:24:36 AM »
In regards to the well-known trend of increased relative cold and snow in the subarctic/midlatitudes, let's clear up the oh-my-god-look-at-the-upcoming-glaciation misnomer and put this trend back into perspective. This trend has been ongoing since 1990 as discussed via WACC and its surmised drivers, e.g. Arctic Amplification, sea ice loss and greater flux or disruption in the AO, polar vortex and jet stream. https://www.esrl.noaa.gov/psd/people/lantao.sun/publications/2016_SPH_GRL.pdf

Quote
The results of this study lead to an important conclusion. The true forced pattern of NH temperature change since 1990—given the trajectory of observed sea ice loss, SST variations, and overall radiative forcing—is characterized as “Warm Arctic, Warm Continents”. In consequence, the observed 24 year trend pattern of winter temperatures since 1990 should not be interpreted as expressing a sustainable trajectory of climate. Rather, the so-called “Warm Arctic, Cold Continents” regime is transient and is becoming increasing unlikely as climate continues to warm.

The perspective that jdallen has regarding all this seems most spot on to me. That being we are amidst a kind of interim chaotic state change where wild fluctuations represent an ongoing drastic shift in our climate and arctic sea ice formation. (hope i paraphrased JD correctly?) My concern and inquiry, with the relative increased continental cold and corresponding decreased atmospheric pressures, is to what degree does WACC create its own positive feedback loop - especially related to the increased cold/decreased pressures that builds in Siberia? Seems like Cohen might be on to something there.
« Last Edit: November 21, 2018, 08:39:02 AM by Ice Shieldz »

Aluminium

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Re: The 2018/2019 freezing season
« Reply #778 on: November 21, 2018, 08:10:40 AM »
November 16-20.

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Re: The 2018/2019 freezing season
« Reply #779 on: November 21, 2018, 09:18:22 AM »
Quote from another topic:

To put current events a bit in perspective: The last time the daily JAXA arctic sea ice extent did not rank in the top 11 was 25th April 2012. Since then, every single day was in the lowest 11 at the time - until yesterday.

That's a great signal for the ice. But on the other hand, we all know what happened the months after the last time it was this "high" in 2012.

Perfect preconditioning for a disastrous melt season?

El Cid

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Re: The 2018/2019 freezing season
« Reply #780 on: November 21, 2018, 10:53:48 AM »
I believe that temperatures tell us the real story about the state of the Arctic. Attached is the November to October (12 months) average temperature 70N-90N (ie, the last data plot is the average temp from 2017 Nov to 2018 Oct). Nothing to cheer at, things are actually worse than 2012 or 2007:
 

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Re: The 2018/2019 freezing season
« Reply #781 on: November 21, 2018, 11:29:25 AM »
I believe that temperatures tell us the real story about the state of the Arctic. Attached is the November to October (12 months) average temperature 70N-90N (ie, the last data plot is the average temp from 2017 Nov to 2018 Oct). Nothing to cheer at, things are actually worse than 2012 or 2007:

It seems a paradox to be getting warmer while the freeze is so fast.
I really have no idea, but is it something to to do with the melting water being fresh and on the surface? Fresh water freezing "better" than saline water?
If there is extra fresh water on top, it freezes fast, leaving saline water underneath potentially holding more heat. Is that a correct line of thinking on a basic level?

If so, is the ice more likely to be thinner and weaker?

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Re: The 2018/2019 freezing season
« Reply #782 on: November 21, 2018, 11:39:56 AM »
Looking at the regional charts, two things stand out:

1) Refreeze in the Central Arctic Basin started very late but vas extremely fast once it began.

2) Only a very few seas are or have been "ahead" of the curve (2012 - 2017): CAA (fully frozen over by now), Beaufort Sea (ditto), Baffin/Newfoundland Bay and Hudson Bay (finally!)

Admittedly the regional charts only show back to 2012, but judging from them the very rapid refreeze has been mostly the Central Arctic catching up (which it hasn't quite managed yet) and the current "surplus" pushing 2018 into 11th place is to be found in Baffin/Newfoundland, Hudson  and (until now) Beaufort.
« Last Edit: November 21, 2018, 11:48:50 AM by binntho »
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binntho

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Re: The 2018/2019 freezing season
« Reply #783 on: November 21, 2018, 11:50:32 AM »
Note that the "high fliers" are all on the Canadian side, in bbr's "reglaciation" area.
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Re: The 2018/2019 freezing season
« Reply #784 on: November 21, 2018, 01:07:38 PM »
It seems a paradox to be getting warmer while the freeze is so fast.

So is the Mpemba effect.

There is no end of study into how mixing affects melt and upwelling of warm water.  I doubt that there has been very large amount of study into the re-freeze in the same way, but I could be wrong.

One of the studies to try and understand the Mpemba effect shows that suddenly stirring very cold water can cause flash freezing.  We know that the pack protects the water from the worst effects of storms.  What we don't know is how weather is affecting water sitting at -1.8c and giving up its heat before freezing.

I'm sure this will be studied in time but, today, we're in fairly uncharted territory.
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uniquorn

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Re: The 2018/2019 freezing season
« Reply #785 on: November 21, 2018, 01:28:07 PM »
I think FOoW mentioned something about storms and ocean heat loss in winter.

2018 catching up with (and overtaking) 2017.
amsr2-uhh, oct21 and nov11 for the two years, 2018 on the left.
oct21:  Beaufort freezing earlier. Laptev/Kara and CAA later
nov11: Beaufort freezing earlier, ESS earlier, Baffin earlier.

There has been a lot of attention on CAA, Baffin and Hudson, but noting the export into the CAA and probable increased meltwater in the Baffin to assist quicker refreeze, the accelerated freeze in the Hudson may just be weather rather than a shift in climate.

edit in italics
« Last Edit: November 21, 2018, 06:06:17 PM by uniquorn »

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Re: The 2018/2019 freezing season
« Reply #786 on: November 21, 2018, 03:11:31 PM »
Agreed. It looks like there is only movement in the Nares now.
Here is a comparison of 2017 and 2018, using amsr2-uhh, from oct1 to nov19. 2017 is outlined in green.

This animation is very, very nice. I wish I could 'like' it twice.
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Re: The 2018/2019 freezing season
« Reply #787 on: November 21, 2018, 03:37:34 PM »
(pentajoule-scale increases in total oceanic enthalpy)

Should be petajoule

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Re: The 2018/2019 freezing season
« Reply #788 on: November 21, 2018, 03:46:53 PM »
Agreed. It looks like there is only movement in the Nares now.
Here is a comparison of 2017 and 2018, using amsr2-uhh, from oct1 to nov19. 2017 is outlined in green.

This animation is very, very nice. I wish I could 'like' it twice.


+1   (+2 is not possible)  ;)
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.

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Re: The 2018/2019 freezing season
« Reply #789 on: November 21, 2018, 04:43:13 PM »
In regards to the well-known trend of increased relative cold and snow in the subarctic/midlatitudes, let's clear up the oh-my-god-look-at-the-upcoming-glaciation misnomer and put this trend back into perspective. This trend has been ongoing since 1990 as discussed via WACC and its surmised drivers, e.g. Arctic Amplification, sea ice loss and greater flux or disruption in the AO, polar vortex and jet stream. https://www.esrl.noaa.gov/psd/people/lantao.sun/publications/2016_SPH_GRL.pdf

Quote
The results of this study lead to an important conclusion. The true forced pattern of NH temperature change since 1990—given the trajectory of observed sea ice loss, SST variations, and overall radiative forcing—is characterized as “Warm Arctic, Warm Continents”. In consequence, the observed 24 year trend pattern of winter temperatures since 1990 should not be interpreted as expressing a sustainable trajectory of climate. Rather, the so-called “Warm Arctic, Cold Continents” regime is transient and is becoming increasing unlikely as climate continues to warm.

The perspective that jdallen has regarding all this seems most spot on to me. That being we are amidst a kind of interim chaotic state change where wild fluctuations represent an ongoing drastic shift in our climate and arctic sea ice formation. (hope i paraphrased JD correctly?) My concern and inquiry, with the relative increased continental cold and corresponding decreased atmospheric pressures, is to what degree does WACC create its own positive feedback loop - especially related to the increased cold/decreased pressures that builds in Siberia? Seems like Cohen might be on to something there.
The trend towards warm arctic cold continents began in 2012. It has accelerated since. Throwing random research and data points instead of reading everything that has been written since is fine. But adding that tidbit re: Cohen is absurd -- he is not onto anything, "SAI" is nonsense, it is simply the same feedback that has always existed that has kicked into higher gear since 2012. Hansen has knowledge, Cohen only produces nonsense acronyms.

bbr2314

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Re: The 2018/2019 freezing season
« Reply #790 on: November 21, 2018, 04:46:36 PM »
PS where is that random new person who screamed at me and hurled insults when I said the models showed severe mid-November cold across North America? LOL.

I just don't see it in the forecast.  To me it looks like the PV at any level is displaced, and the timing is coincident with the influence of an extratropical cyclone entering the arctic.  As the GFS outlook has evolved, the PV moves away from the north pole toward Svalbard and Siberia, but quickly recovers around Nov 15

I wouldn't predict necessarily but it seems to indicate milder weather mid-month for the Eastern US and Canada.
« Last Edit: November 21, 2018, 05:00:02 PM by bbr2314 »

Ice Shieldz

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Re: The 2018/2019 freezing season
« Reply #791 on: November 21, 2018, 05:20:38 PM »
Quote
The trend towards warm arctic cold continents began in 2012
Did you even read the article i posted?  It defines WACC beginning in 1990 and shows actual data that clearly backs up the trend.

Quote
But adding that tidbit re: Cohen is absurd -- he is not onto anything, "SAI" is nonsense, it is simply the same feedback that has always existed that has kicked into higher gear since 2012.
What?  This is exactly what i'm referring to about WACC having a positive feedback, i.e. accelerating itself and making it even more of a climatological flash in the pan - so to speak. What is your point and where is your science and data?
« Last Edit: November 21, 2018, 06:27:07 PM by Ice Shieldz »

Shared Humanity

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Re: The 2018/2019 freezing season
« Reply #792 on: November 21, 2018, 07:24:34 PM »
It's been a few days. Thought I would review the freeze progress for Hudson Bay. Rapid freezing continues but it looks like it may be a few more days before the freeze is "mostly done".

Tor Bejnar

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Re: The 2018/2019 freezing season
« Reply #793 on: November 21, 2018, 08:11:59 PM »
BBR,
If I understand your November 13 prediction (#685 in this thread), Hudson Bay (HB) is going to have 75% ice coverage by 11/15 (plus 6 days, because we are among friends) using NATICE.  I found a few references to "NATICE" in this thread, but no links.  Can you provide one, so that we can connect your prediction with the reference you specified?  Today is the day, but tomorrow (or the next day, I presume) will show today's extent.  (The ASIG-regional [a different calibration, for sure], as SH posted, shows for HB less than 50% extent as of yesterday.)
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gerontocrat

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Re: The 2018/2019 freezing season
« Reply #794 on: November 21, 2018, 08:38:50 PM »
BBR,
If I understand your November 13 prediction (#685 in this thread), Hudson Bay (HB) is going to have 75% ice coverage by 11/15 (plus 6 days, because we are among friends) using NATICE.  I found a few references to "NATICE" in this thread, but no links.  Can you provide one, so that we can connect your prediction with the reference you specified?  Today is the day, but tomorrow (or the next day, I presume) will show today's extent.  (The ASIG-regional [a different calibration, for sure], as SH posted, shows for HB less than 50% extent as of yesterday.)

As at 20 Nov -
NSIDC Area circa 25% of max,
NSIDC extent circa 50% of max

and that's all I'm going to say about that
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uniquorn

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Re: The 2018/2019 freezing season
« Reply #795 on: November 21, 2018, 08:57:52 PM »
Worldview, north of Svalbard, brightness temperature, band15,night, nov20-21.
The lower concentration ice near to the eddy (circled) still clearly visible over recent days. They look like goodbye waves and cloud streets along the ice front. Large floes on the ice edge ~-28C.

For those who missed it first time round, some cloud street info from A-Team

"cloud streets" in the Barents (associated with cold winds of a meandering central anti-cyclonic high) will continue out to March 25th and beyond, per GFS.

Twitter can confuse these with with blowing Antarctic ice needles or katabatic Greenland winds but Zach notes correctly today these are parallel bands of cumulus clouds that form as cold winds from the north blow off the ice edge onto warmer ocean waters.

OK, but why now, why cumulus mediocris, and what causes the street banding? 

The temperature differential between cold air blowing off the ice and the sea surface water, either open leads or more commonly beyond the ice edge, can easily exceed 20ºC in March. Thermal columns of moist heated air rise off the sea surface until they hit a denser warmer lid of air (provided a temperature inversion is present).

As the thermals are advected downwind and sink or rise according to ambient density differences, they form parallel pairs of counter-rotating cylinders of air. On the upper surface of rising air, water vapor cools and condenses into flat-bottomed, fluffy-topped clouds (ie cumulus: https://en.wikipedia.org/wiki/Cumulus_cloud). On the downdrafts, condensates evaporate giving clear skies on the sides of the clouds, the banding.

Surprisingly, the alignment of vortices alone does not reliably indicate wind direction. Stably stratified environments have lines 30° off CCW to the left; only an unstably stratified (ie convective) situation has bands parallel to mean wind.

Cloud streets are technically called horizontal convective rolls. The most favorable conditions for them occur when the lowermost layer of air is unstable, driven by a moderate wind and capped by a stable inversion, a common situation when upper air is subsiding, such as under recently prevailing anticyclonic conditions.

https://en.wikipedia.org/wiki/Horizontal_convective_rolls turbulent momentum flux in PBL
<snip>

Tech note: brightness/contrast adjusted and clahe applied to the worldview images

bbr2314

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Re: The 2018/2019 freezing season
« Reply #796 on: November 21, 2018, 09:49:18 PM »
BBR,
If I understand your November 13 prediction (#685 in this thread), Hudson Bay (HB) is going to have 75% ice coverage by 11/15 (plus 6 days, because we are among friends) using NATICE.  I found a few references to "NATICE" in this thread, but no links.  Can you provide one, so that we can connect your prediction with the reference you specified?  Today is the day, but tomorrow (or the next day, I presume) will show today's extent.  (The ASIG-regional [a different calibration, for sure], as SH posted, shows for HB less than 50% extent as of yesterday.)

As at 20 Nov -
NSIDC Area circa 25% of max,
NSIDC extent circa 50% of max

and that's all I'm going to say about that
Those are 5 day trailing averages so that is not fair.

Re: NATICE --

https://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_usa.gif

jdallen

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Re: The 2018/2019 freezing season
« Reply #797 on: November 21, 2018, 11:01:21 PM »
(pentajoule-scale increases in total oceanic enthalpy)

Should be petajoule
Thank you for the correction.  I plead haste and fatigue.
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uniquorn

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Re: The 2018/2019 freezing season
« Reply #798 on: November 22, 2018, 12:36:46 AM »
Very long leads across the CAB recently, best seen from nov14-16 on worldview bt15n.
https://tinyurl.com/ybynxmdl
A large catchment area for Fram Strait export as well

Tor Bejnar

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Re: The 2018/2019 freezing season
« Reply #799 on: November 22, 2018, 02:09:22 AM »
Thanks BBR.
NATICE for today.  Is HB 75% covered?  I don't think so, but I don't have a pixel counter.
NOAA's NATICE
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