Support the Arctic Sea Ice Forum and Blog

Author Topic: Atmospheric connections, structure, and long range weather forecasting  (Read 86271 times)

sark

  • Guest
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #400 on: October 20, 2020, 08:59:17 PM »
Find me another single month that is split at 500mb in the NH as I have shown repeatedly and I would reconsider this stat as a measure of anything.  feel free to adjust the scale, it may be not what I am imagining.

pointing at a massive average of the geopotential heights is not yet useful, and when it becomes apparent that annual or even seasonal averages are split at 500mb, I'm not confident we will retain the capacity to observe it.

The Earth is still round.. Is that the test?

Is splitting at 500mb a useful test?  It's a valid question.
« Last Edit: October 20, 2020, 09:22:01 PM by sark »

sark

  • Guest
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #401 on: October 20, 2020, 09:28:50 PM »
It seems that what would clear things up is a simple vorticity heat map of the hemisphere.  This might show that the split in heights is accompanied by a split in vorticity, which is really the issue.  Anyone got that?

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #402 on: October 20, 2020, 11:10:20 PM »
you are right
2020 October is highly unusual

sark

  • Guest
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #403 on: October 21, 2020, 12:37:41 AM »
Wow, it really is.  Hopefully a lot of this fills in as we had peak events around the 4th and 17th of the month.

sark

  • Guest
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #404 on: October 22, 2020, 07:36:03 AM »
Building in positive AAM could change the polar blocking situation in coming months, but unlike last year, our La Nina episode favors more negative AAM.

Looks like we're coming into a seasonal acceleration,  but in La Nina perhaps not as much as last year.

https://www.aer.com/science-research/earth/earth-mass-and-rotation/special-bureau-atmosphere/

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #405 on: October 29, 2020, 11:34:16 PM »
Warmer climate and Arctic sea ice in a veritable suicide pact https://yaleclimateconnections.org/2020/10/warmer-climate-and-arctic-sea-ice-in-a-veritable-suicide-pact/

----------------------------------
      Excerpt:  “Ever since the record-smashing summer of 2012, Arctic scientists have watched melt seasons unfold with bated breath: Will this year break the record again? Will this year bring the long-anticipated sea-ice-free summer?” said climate scientist Jennifer Francis of the Woodwell Climate Research Center. “And almost every August, the rate of ice loss came to a screeching halt, averting a new record minimum. But why?”

"What froze the death spiral?
      Francis and her co-author Bingyi Wu of Fudan University in Shanghai have a theory that the rapid warming in the Arctic prompted a change in the polar jet stream, the narrow band of strong wind circling the region; they theorize that this change helped preserve some sea ice. Their new study in Environmental Research Letters notes that the winter and spring sea ice extent reached record low levels nearly every year since 2012 … but then the trajectory took a sharp turn late into the summer season, with the loss curbing early and therefore avoiding setting a new record low annual minimum in September.

      Francis and Wu identified a common pattern in atmospheric air circulations during many of the summers since 2012: Low-pressure systems would develop in the Arctic, forming clouds that kept temperatures cool by blocking sunlight and generating winds that spread out the remaining ice."

      The study discussed is available via open access at https://iopscience.iop.org/article/10.1088/1748-9326/abc047/pdf
----------------------------------
 
      Good article, but I don't think ASIF vets have been very surprised that the devastating 2012 freak-cyclone bottom-fell-out crash has not been repeated in the few years since.  Maybe Francis should call sark for additional insight on those jet stream patterns.

      What is more notable than the 2012 records lasting this long is that due to continuation of the long-term trends, both 2019 and 2020 approached the same melt levels as 2012 without input from freak events.  The GAC 2012 certainly made its mark, but because it used up some stored heat in doing so, the subsequent years saw a regression back to the trend line.  But now even the "new normal" levels are near (and going below in 2021?) what used to be freakishly low record-breaking levels less than a decade before.  Welcome to the future.  It didn't take very long to get here. 

       So that I can tell myself I'm not just kvetching, here is my attempt at an inspiring conclusion: - Do not go quietly into this dark night, talk about it, and please make sure that you, and folks in your social networks, vote climate wherever you live at every opportunity.  This insanity won't end until we make it end.  The infrastructure and other changes required to remake society (Make Earth Great Again?  :-\) is not only essential, it is the perfect opportunity to address many other interconnected social, economic and environmental problems.  To the guy who recently said "We can do this", I'll add "We HAVE to do this."
« Last Edit: October 30, 2020, 01:45:06 AM by Glen Koehler »
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #406 on: October 31, 2020, 10:20:38 AM »
I have long thought that as the Arctic seas remain open longer during autumn, the Aleutian Low will be displaced. I think this might be happening this year. When you have very warm seas and continental land masses cool during October, cold air moves toward the warm seas and rises, creating our well know Icelandic and Aleutian Lows. What happens though when the Siberian seas are very warm? It seems that the Aleutian low is displaced and a new, Siberian Seas Low is created (I believe that eventually this will morph into the Arctic Low when we reach BOE). You can see this year's air pressure chart on the first pic, and the climatological average on the second. The Aleutian low is very weak, and there is a new low in the Siberian Seas.

The loss of the Aleutian Low has significant consequences for NH weather. The Aleutian Low used to push wet, mild air into Canada, warming it and separating colder, Arctic airmasses from the US. As you can see on the third picture, the lack of these airmasses led to cold breakouts into the US this year. Also, as warm Atlantic air is no longer pushed towards Mongolia but instead into Northern Siberia/ESS region, the inner parts of Eurasia are also cooler than average.
« Last Edit: October 31, 2020, 10:30:11 AM by El Cid »

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #407 on: October 31, 2020, 10:28:52 AM »
To elaborate on the above, I think it is easier to understand what I try to convey if I draw the current (old) setup during autumn with the Aleutian and Icelandic Lows, and the proposed new setup with a unified Arctic Low. This would likely lead to a significantly warmer Alaska, cold breakouts into the USA, and Europe staying warm.

Any comments are welcome

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #408 on: October 31, 2020, 03:13:56 PM »
In your second map, I think the green arrow should be pointing down on the Rockies / towards the Glacier National Park and Yellowstone vicinity / arcing down the Rockies, but I think your points are cogent and likely correct.  :)

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #409 on: October 31, 2020, 05:19:15 PM »
     El Cid - you asked for comments, so here goes from someone who knows little about the air mass dynamics.  Even with the Siberian seas warming, it seems that the net difference and thus interaction between the Siberian seas and the very cold Siberian land mass in winter may not change that much, or may change in the other direction. 

       With a more insulating CO2-enhanced atmosphere, the winter land mass must also be warming by as much or more than the Siberian seas are warming.  Globally, land masses are warming faster than the oceans.  So presumably that is also true around the Arctic Ocean.  If so, how does that affect your hypothesis?
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #410 on: October 31, 2020, 09:43:15 PM »
  Globally, land masses are warming faster than the oceans.  So presumably that is also true around the Arctic Ocean.  If so, how does that affect your hypothesis?

Well, it's not true. Sea pic. The Arctic seas are warming more than Siberia during autumn

BTW, my main point really is a replacement of the Aleutian Low in the future by a generalized Arctic Low during open seas (likely Sep-Oc-Nov), leading to changed atmospheric circulation. 2020 October is showing a pattern like that.

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #411 on: October 31, 2020, 10:21:51 PM »
     That temperature map is not convincing.  A temperature map of the Arctic Ocean and surrounding landmass is needed, not a side view with the Arctic gets crushed into a thin slice at the top.  From what I recall Siberian land temperatures have frequently been 10C or more above historical norms in 2020 vs. Siberian sea temperature anomalies much lower than that.  So based on that larger net difference, I would say Siberian land mass is warming faster than Siberian seas. 

     Again, the whole field is out of my league, so I have no opinion about how relative land vs sea temperatures might affect air pressure distribution, variability, timing, or resulting weather.  I'm just questioning the assertion that Siberian seas are warming faster than land.  On a global basis that is not the case, so it would be odd for the Arctic to follow a different pattern.  But I just re-read your original message, and your hypothesis does not require seas to be warming more than land, just that cold air coming off of land now overlays seas that were warmer than they used to be.  Which is certainly the case for open water vs. ice covered sea.  So I'm outta here!
« Last Edit: October 31, 2020, 10:46:11 PM by Glen Koehler »
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

be cause

  • Nilas ice
  • Posts: 2441
    • View Profile
  • Liked: 1012
  • Likes Given: 1034
Conflict is the root of all evil , for being blind it does not see whom it attacks . Yet it always attacks the Son Of God , and the Son of God is you .

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #413 on: October 31, 2020, 10:48:27 PM »
Once upon a time at this time of year we would be looking at a snow covered frosty Siberia seamlessly merging into the snow covered frozen Siberian Seas.

As the years have rolled by things have changed until  we now look at a pretty much snow-covered Siberia looking over a vast area of open water from the ESS to the Kara.

I guess that has a climatic effect, including a big increase in the temperature gradient from the deeply frozen high Arctic Siberian land to the above freezing open water until such time that open water is frozen. And as the years roll by open water will last longer. Hence the shift in the lows and highs until everywhere is frozen again.

That is my speculation that belongs to me even if it is stolen from El Cid
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #414 on: October 31, 2020, 10:53:15 PM »
 
current Siberian anomaly for example ? ..  https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=290316;image
   You got me on that one!  I was focused on global year-round land vs ocean warming.  I look at the Arctic Ocean temp. anomaly on CR regularly, so you'd think the ocean vs land difference would have sunk in.  Useful to be reminded of my ability to misperceive or misplace evidence. 8)
« Last Edit: October 31, 2020, 10:59:42 PM by Glen Koehler »
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

Positive retroaction

  • New ice
  • Posts: 51
    • View Profile
  • Liked: 29
  • Likes Given: 160
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #415 on: November 02, 2020, 12:06:09 AM »
I have read several things about the consequences of the retreat of arctic ice on Western Europe, but very little certainty is there it seems.
But I also wanted to have your opinion
Is there a risk that there will be colder autumns and winters (which was expected due to the slowing down of the gulf stream and which did not happen)?
Sorry, excuse my bad english

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #416 on: November 02, 2020, 07:52:11 AM »

Is there a risk that there will be colder autumns and winters (which was expected due to the slowing down of the gulf stream and which did not happen)?

Hansen et al had a study about the slowing of AMOC and colder winters. I wouldn't put too much weight on localized forecasts though. Our current climate models still wrongly "backcast" Europe's Holocene optimum precipitation and temperature patterns and they are also unable to replicate the Green Sahara that is obvious from paleodata. Both happened within 10 000 years.

I think the generalized view for winter is that with the Arctic warming, the Siberian High should weaken, which should reduce major cold breakouts from there and that should warm Europe up. At the same time however, the jetstream would be wavier which should create more Arctic (cold) and more African (warm) intrusions during winter. Good thing is that with the Arctic warming, those cold breakouts (though more numerous) should be not as cold as in the past.

My speculation that belongs to me (wording copyright by gerontocrat)  is therefore that the weather should be more changeable with some weeks of very, but not record cold weather but average temperatures will be going up (and weeks of November-like temperatures) . So far, that seems to be the case as shown for the past years when the Arctic was warm=Siberia was warm=Europe was warm

Positive retroaction

  • New ice
  • Posts: 51
    • View Profile
  • Liked: 29
  • Likes Given: 160
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #417 on: November 02, 2020, 12:21:17 PM »

Is there a risk that there will be colder autumns and winters (which was expected due to the slowing down of the gulf stream and which did not happen)?

Hansen et al had a study about the slowing of AMOC and colder winters. I wouldn't put too much weight on localized forecasts though. Our current climate models still wrongly "backcast" Europe's Holocene optimum precipitation and temperature patterns and they are also unable to replicate the Green Sahara that is obvious from paleodata. Both happened within 10 000 years.

I think the generalized view for winter is that with the Arctic warming, the Siberian High should weaken, which should reduce major cold breakouts from there and that should warm Europe up. At the same time however, the jetstream would be wavier which should create more Arctic (cold) and more African (warm) intrusions during winter. Good thing is that with the Arctic warming, those cold breakouts (though more numerous) should be not as cold as in the past.

My speculation that belongs to me (wording copyright by gerontocrat)  is therefore that the weather should be more changeable with some weeks of very, but not record cold weather but average temperatures will be going up (and weeks of November-like temperatures) . So far, that seems to be the case as shown for the past years when the Arctic was warm=Siberia was warm=Europe was warm

Thank you El Cid
I had not thought of the descents of less cold air of Siberia
However in recent years the synoptic means that this happens infrequently
On the other hand, the changes on the jet stream you are talking about also confirm what I had read
The studies also said that there could be more descent of polar air in Western Europe.
This year in October we had several descents of cold air coming from the north, with strongs and catastrophic rainfall, because of a jet which is shifted towards the south and less strong, whereas for several years we had very beautiful beginning of autumn.
Thank you
It therefore appears that warming can cause a recurring event (warms autumns without rain) but then an increase in warming possibly can reverse this event.(cooling autumns and rain)
I find it fascinating, Europe is not the only example
Sorry, excuse my bad english

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #418 on: November 02, 2020, 01:15:09 PM »
This is a good piece of research:

https://www.researchgate.net/publication/307767206_The_influence_of_atmospheric_circulation_on_the_mid-Holocene_climate_of_Europe_a_data-model_comparison

I had quoted it before on some other thread.

This one shows how wrong models get (the likely as warm as or somewhat warmer than present) Holocene Optimum in Europe probably due to changes in atmospheric circulation.
N-Europe seems to have been much warmer during winter than models suggest and S-Europe much wetter and cooler during summer:


El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #419 on: November 11, 2020, 05:02:16 PM »
Back to my pet theory about the loss of the Aleutian low and its replacement by a big Arctic Low. And its consequences. We see this beautifully on the next 10 day GFS average forecast. One huge Arctic Low ,no Aleutian Low. Result: cold NA, warm Europe and Siberia.

Tfitz

  • New ice
  • Posts: 1
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #420 on: November 13, 2020, 03:24:37 PM »
This blog has weekly winter forecasts that attempt to integrate all kinds of data including arctic sea ice and subsequent geopotential heights. It also goes in depth into the behavior of the polar jet. I assume people have already seen it, but if not, here is the link. Judah Cohen, the writer of the blog, is a climatologist.

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

I apologize if this doesn't fit the theme of this thread, feel free to delete it away if so.

oren

  • Moderator
  • First-year ice
  • Posts: 9805
    • View Profile
  • Liked: 3584
  • Likes Given: 3922
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #421 on: November 14, 2020, 12:07:43 AM »
Welcome, Tfitz.

FishOutofWater

  • Nilas ice
  • Posts: 1088
    • View Profile
  • Liked: 696
  • Likes Given: 332
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #422 on: November 14, 2020, 12:15:07 AM »
Sark, that 500mb map at the top of the page shows the tropospheric polar vortices which normally split, one in Siberia and one in Canada. It's relate to cold air over the continents and warm air over the N Pac ant N Atl. It helps to do background reading to understand the climatology before you start talking about anomalous behavior.

There are large positive GPH anomalies over the Barents and Kara seas because of theocean heat there warming the atmosphere, but the Siberian vortex and Canadian vortex are not by themselves anomalous.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #423 on: November 20, 2020, 04:43:29 PM »
Observation:

Since 2007, whenever the Hudson freezes over early, winters are usually milder in Europe. May have something to do with the "Pole of Cold" being displaced to the American side saving Europe from the cold...

SimonF92

  • Grease ice
  • Posts: 592
    • View Profile
  • Liked: 210
  • Likes Given: 87
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #424 on: November 20, 2020, 05:27:30 PM »
Observation:

Since 2007, whenever the Hudson freezes over early, winters are usually milder in Europe. May have something to do with the "Pole of Cold" being displaced to the American side saving Europe from the cold...

I was curious about this, so I graphed it. One is DJF, one is JFM
Bunch of small python Arctic Apps:
https://github.com/SimonF92/Arctic

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #425 on: November 20, 2020, 09:49:50 PM »
Observation:

Since 2007, whenever the Hudson freezes over early, winters are usually milder in Europe. May have something to do with the "Pole of Cold" being displaced to the American side saving Europe from the cold...

I was curious about this, so I graphed it. One is DJF, one is JFM

Two things.

1) I should have said that I used Dec 1 values
2) I think you might have mixed up the numbers, because for example the 2019 Dec 1 ice extent values need to be paired with 2019 Dec, 2020 Jan 2020 Feb temparatures (3,4C anomaly not 1,2 C as seen on your chart). I think you paired it with 2018Dec, 2019Jan, 2019Feb

here is my chart where Dec1 Hudson ice cover is paired with Copernicus European DJF anomaly:

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #426 on: November 20, 2020, 09:58:11 PM »
What's more, my observation is that the more open the Chukchi and the more iced over the Hudson, the warmer it is in Europe during winter. So here I plot Hudson % ice cover minus Chukchi %icecover on Dec 1, and European winter temp anomaly. Lo and behold

SimonF92

  • Grease ice
  • Posts: 592
    • View Profile
  • Liked: 210
  • Likes Given: 87
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #427 on: November 20, 2020, 10:26:45 PM »
Observation:

Since 2007, whenever the Hudson freezes over early, winters are usually milder in Europe. May have something to do with the "Pole of Cold" being displaced to the American side saving Europe from the cold...

I was curious about this, so I graphed it. One is DJF, one is JFM

Two things.

1) I should have said that I used Dec 1 values
2) I think you might have mixed up the numbers, because for example the 2019 Dec 1 ice extent values need to be paired with 2019 Dec, 2020 Jan 2020 Feb temparatures (3,4C anomaly not 1,2 C as seen on your chart). I think you paired it with 2018Dec, 2019Jan, 2019Feb

here is my chart where Dec1 Hudson ice cover is paired with Copernicus European DJF anomaly:


Ah, i stupidly did those plots and then didnt save the script, so I cant double check- but I am sure you are correct given you have the data to hand. My mistake!
Bunch of small python Arctic Apps:
https://github.com/SimonF92/Arctic

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #428 on: November 20, 2020, 10:41:37 PM »
What's more, my observation is that the more open the Chukchi and the more iced over the Hudson, the warmer it is in Europe during winter. So here I plot Hudson % ice cover minus Chukchi %icecover on Dec 1, and European winter temp anomaly. Lo and behold
This is fantastic work!

I wonder if the correlation is stronger in Nov / can you do .... 11/20?

And include the % of ice in Hudson this year? (but not on the graph), I think we are above 2018...

Based on where we already are, I would bet Europe is +1.5C or greater this winter.

Is it also possible to include North America in this in a separate graph?

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #429 on: November 21, 2020, 07:53:26 AM »
I do think it is a very important teleconnection and I have never read about it anywhere, so I might eventually get the Nobel Prize for this :) :) :)

Anyway, I don't have the NA temp anomaly data at hand but if you can point it to me, I'll do the math. (my main interest was and is Europe as I live here)

As for dates: Nov 20 works worse. It seems to me that Dec 1 is the best.

As for current numbers: Hudson minus Chukchi % is currently below 2017,18,19, but above all other years. Would suggest a warmer European winter

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #430 on: November 21, 2020, 02:01:24 PM »
I do think it is a very important teleconnection and I have never read about it anywhere, so I might eventually get the Nobel Prize for this :) :) :)

Anyway, I don't have the NA temp anomaly data at hand but if you can point it to me, I'll do the math. (my main interest was and is Europe as I live here)

As for dates: Nov 20 works worse. It seems to me that Dec 1 is the best.

As for current numbers: Hudson minus Chukchi % is currently below 2017,18,19, but above all other years. Would suggest a warmer European winter
Thank you! Let's see how they look 12/1 I guess...! And I wish you luck on the Nobel  ;D

kassy

  • First-year ice
  • Posts: 8235
    • View Profile
  • Liked: 2042
  • Likes Given: 1986
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #431 on: November 21, 2020, 04:36:40 PM »
Since you wrote ´since 2007´ is this a pattern that does not hold in the years before 2007 or have you only looked at from that date?
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #432 on: November 21, 2020, 05:07:46 PM »
No, it did not work before 2007, and yes it might be a coincidence.

However, I think it has some merit, because it there is some logic behind it: the Arctic seas have become very hot (vs the past) and 2007 seems to have been a sort of regime change.
The very hot seas likely change the course of the jet stream and push cold air either into Siberia or NA (or keep the cold air there). If the Chukchi is very much open and the Hudson is iced over then it means that the cold is diverted to NA and the Siberian cold pole is not as strong as usual, making European winters warmer.
I am not a climate scientist, so there might be weak spots in my argument though

kassy

  • First-year ice
  • Posts: 8235
    • View Profile
  • Liked: 2042
  • Likes Given: 1986
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #433 on: November 21, 2020, 07:27:08 PM »
Probably not a coincidence more like patterns establishing.

I would love to see the years for your dots on both graphs.

And since maybe you looked at it how does it correlates with the beasts from the east...there was one DEC 2016 and FEB 2018. First one should correlate better then the second?
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #434 on: November 21, 2020, 09:51:58 PM »
here it goes with labels... plus I attach a European temp anomaly (7yrs moving average) chart just to point out the amazing changes that have happened the past few years: European winters suddenly became much warmer!

kassy

  • First-year ice
  • Posts: 8235
    • View Profile
  • Liked: 2042
  • Likes Given: 1986
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #435 on: November 21, 2020, 11:58:46 PM »
It also relates to declining siberian land ice cover declining.

Wayne from EH2R (and frequent ASIB commenter) used to write a lot about cold poles and how they move about. They used to be on the arctic ice or move over it and that does not happen any more.

The american side is near the Greenland cold spot and where some remnant ice usually is so usually it is colder then siberia. This sets up a pattern. There is a cold spot there now but it is weaker then Greenland/NA.

In the summer season you now see lots of weather/clouds just shoot over the asian continent.
In the old days it would have ran into the cold, maybe come down as snow but that is happening later and later.

I think the teleconnection works because it is a good proxy for setting up the cold poles on the american side which pulls relatively more heat from the siberian side.




Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #436 on: November 22, 2020, 04:21:44 AM »
It also relates to declining siberian land ice cover declining.

Wayne from EH2R (and frequent ASIB commenter) used to write a lot about cold poles and how they move about. They used to be on the arctic ice or move over it and that does not happen any more.

The american side is near the Greenland cold spot and where some remnant ice usually is so usually it is colder then siberia. This sets up a pattern. There is a cold spot there now but it is weaker then Greenland/NA.

In the summer season you now see lots of weather/clouds just shoot over the asian continent.
In the old days it would have ran into the cold, maybe come down as snow but that is happening later and later.

I think the teleconnection works because it is a good proxy for setting up the cold poles on the american side which pulls relatively more heat from the siberian side.
Agree with this, this is also why the ice keeps detaching from the Siberian front, as the downsloping katabatic winds from the mountains / plateaus adjacent are now much more frequent and much warmer due to what you have described.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #437 on: November 22, 2020, 07:08:45 AM »

I think the teleconnection works because it is a good proxy for setting up the cold poles on the american side which pulls relatively more heat from the siberian side.

that is what I think too but I don't have the atmospheric physics knowledge to (sort of) prove it...

uniquorn

  • First-year ice
  • Posts: 5117
    • View Profile
  • Liked: 2163
  • Likes Given: 388
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #438 on: November 22, 2020, 01:40:37 PM »
Ice detaching from the Siberian front, amsr2-uhh, sep2019-jul2020. Wind played a big part, later refreeze in the ESS didn't help. (click 10MB)

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #439 on: November 23, 2020, 10:17:10 AM »
What's more, my observation is that the more open the Chukchi and the more iced over the Hudson, the warmer it is in Europe during winter. So here I plot Hudson % ice cover minus Chukchi %icecover on Dec 1, and European winter temp anomaly. Lo and behold

     Quotes below are from
"Warm Arctic, Cold Continents? It Sounds Counterintuitive, but Research Suggests it’s a Thing"
https://insideclimatenews.org/news/20112020/warm-arctic-cold-continents-climate-change

    "Low sea ice in the Chukchi Sea, north of Alaska, seems to match up with severe winter conditions in Eastern North America, and low sea ice in the Barents and Kara Seas, north of Siberia, match with cold winters over Asia."

    But there is disagreement about the strength of the effect, with Jennifer Francis and James Screen expressing different views.

    And this from Judah Cohen:
    ""I'm not arguing that winters are getting colder, I'm saying winters are colder than the models predict, and I think that will continue," he said. "The models are constantly being updated, every winter and the divergence between their projections and the observations is striking." By contrast, he added, the model predictions for summers are nearly perfect."
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #440 on: November 23, 2020, 11:05:11 AM »
I think that there were actually two regimes since the end of 2006:

1) The Barents opened up suddenly in 2006 autumn (The Barents was on average 47% iced over on Dec 1 between 1990-2005, since 2006 it is 23% iced over on average). This destabilized the polar vortex, made the jetstream wavier , made Siberia very cold during winter and led to cold outbursts from Siberia into Europe. This lasted until 2013. First picture is 2006-13 winter temperature anomaly, you can see this. Most studies (eg. Francis) were written using data from this period, noting how cold winters have become (or how unusual cold breakouts we experience at times) .
 
2) Since 2014 the Chukchi opened up. Between 2006-13 the Chukchi was on average 77% iced over on Dec1. Since 2014 it has been on average 53% iced at the same date. This led to warm intrusions from the Pacific side, stopping breakouts towards Asia, leaving Greenland/Canada the new Cold Pole. This can be seen on the second picture (winters between 2014-2020). This regime keeps NA cold, but Eurasia is warm. Since Judah Cohen is based in the USA he seems biased by his own experience of cold winters.

The third picture shows the difference between 2014-20 and 2006-13. Very stark differences can be seen

To sum it up: if you see a very much open Chukchi and iced over Hudson, then chances are that we are in the "new regime", which keeps Siberia warm, and thereby Europe as well.
« Last Edit: November 23, 2020, 11:14:19 AM by El Cid »

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #441 on: November 23, 2020, 05:28:28 PM »
I wonder if the third domino to fall is Hudson, but in the reverse order, with the shift beginning in 2015, and accelerating in 2017-2018?

And then maybe then this is the trigger for Laptev and / or Kara then following the Barentz...

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #442 on: November 26, 2020, 09:28:18 PM »
I wonder if the third domino to fall is Hudson, but in the reverse order, with the shift beginning in 2015, and accelerating in 2017-2018?


Interesting thought. This is Hudson ice extent on Dec1. 2018 was the highest value since 2004. 2020 (red line, expected value for Dec 1) seems to be following 2018 closely.

New Pole of Cold forming there?

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #443 on: November 27, 2020, 02:59:06 AM »
I wonder if the third domino to fall is Hudson, but in the reverse order, with the shift beginning in 2015, and accelerating in 2017-2018?


Interesting thought. This is Hudson ice extent on Dec1. 2018 was the highest value since 2004. 2020 (red line, expected value for Dec 1) seems to be following 2018 closely.

New Pole of Cold forming there?
Maybe highest value since early 90s this year.

This was as of 11/23 and the ice has expanded rapidly. It appears way ahead of 2018, which started quickly but then stalled by the end of the month for a bit.



https://worldview.earthdata.nasa.gov/?v=-3357835.265805248,-3583799.319646948,-789643.2658052479,-2294352.9196469486&p=arctic&l=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #444 on: November 27, 2020, 07:40:23 AM »
We are roughly equal to 2018 now (see pic). Other than that we are ahead of all years since 1995 in terms of Hudson (as of 11/25)

bbr2315

  • Grease ice
  • Posts: 580
    • View Profile
  • Liked: 73
  • Likes Given: 77
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #445 on: November 27, 2020, 03:53:34 PM »
We are roughly equal to 2018 now (see pic). Other than that we are ahead of all years since 1995 in terms of Hudson (as of 11/25)
I think we are now ahead. 2018 stalled or shrank from here to 12/1, I think? We are going to be very far ahead of all years since 1995 by then, IMO, the refreeze at that point should be nearing 80-100%.

Glen Koehler

  • Grease ice
  • Posts: 931
    • View Profile
  • Liked: 738
  • Likes Given: 1413
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #446 on: December 01, 2020, 10:27:43 PM »
I am not sure these seasonal forecasts are good for anything....
If you are right about that, that's an awful lot of highly skilled time...wasted...

     A couple of years ago I did some home-brew testing of the skill of  short-term and "seasonal" (=3 month groupings) forecasts for temperature and precipitation.  The criterion was how much improvement the forecasts/outlooks provided compared to a simple climatology estimate as to whether the period would be in the upper, middle, or lower third relative to <edit> the 30 year historical average the ca. 100 years in the historical record.  Thus the climatology estimate was a 33.3% chance of each.  A 10% improvement would mean that the forecast tool picked the right tercile 36.6% of the time.  A 20% improvement represents picking the right tercile almost 40% of the time.

     Results are shown in charts below.  Note that the testing is done on NOAA forecasts and outlooks for the Northeastern United States, not the Arctic.  Also note that the scales on the two charts are different. 

     The first chart shows that at the 1-month range, forecast skill is down to around 10% improvement over climatology.  The skill decay shown on the chart is relative to the very high skill for the short-range forecasts.  So it is a glass half-full vs. half-empty situation.  Short-range temperature forecasting is really good, so it is not surprising that longer-range outlooks have less skill. 

     I was surprised that the 1-3 and 2-4 month temperature outlooks were better than the 1-month outlooks.  That may be a fluke, but it may be because they benefit from estimating temperature over a longer, and therefore less specific, time period. 

     If we consider 10% improvement over climatology as a threshold for useful improvement, then the first chart shows that temperature outlooks, with skill improvement of ca. 15-20% out to at least 2-to-4 months, have some long-range skill for the northeastern U.S.  Conversely, precipitation forecasts run out of skill between 14 days and 1-month.  That lines up with some studies I've seen that found long-range precip forecasting losing skill at about 3 weeks.  But that's just me waving my arms about stuff I don't keep up with or in detail, so buyer beware.

     The second chart (using a more compressed vertical axis scale) shows that within the multi-month outlooks, the temperature outlooks stayed above 10% improvement out to the 4-to-6 month range, whereas precipitation skill bumps around the floor of statistical noise at every range from 1-to-3 months and beyond, thus again indicating a lack of long-range precipitation forecast skill (but they at least avoided negative scores which were possible).

     That uptick at 7-9 months for temperature forecasts is intriguing.  It could just be statistical noise.  But it could also reflect ENSO (El Nino/La Nina) forecasts actually having some slight (remember, we are talking about a mere 10% improvement over random guessing) skill at nudging the prediction in the right direction.

     A few years ago at a climate modeling workshop in Florida I met lots of folks from the southeast U.S. and got a different view of things vs. my home turf where there seems to be little attention given to local impact of ENSO forecasts.  But those southeastern U.S. folks absolutely worship the ENSO forecasts.  With good reason, as there is much higher correlation for their region with regard to the ENSO effects on temperature, and especially precipitation, in the following months.  That highlights the fact that my informal (not subjected to statistical significance) testing for the northeastern U.S. does not necessarily apply to even other U.S. regions, much less the entire planet.
« Last Edit: December 02, 2020, 04:46:27 PM by Glen Koehler »
“What is at stake.... Everything, I would say." ~ Julienne Stroeve

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #447 on: December 02, 2020, 08:41:06 AM »
That is great work Glen!

Looking at your data, in my book it still says that long term forecasts are mostly crap

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #448 on: December 02, 2020, 12:58:43 PM »
That is great work Glen!

Looking at your data, in my book it still says that long term forecasts are mostly crap
But an improvement on totally crap?
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: Atmospheric connections, structure, and long range weather forecasting
« Reply #449 on: December 02, 2020, 01:55:40 PM »
That is great work Glen!

Looking at your data, in my book it still says that long term forecasts are mostly crap
But an improvement on totally crap?

 :) :) :)