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gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3550 on: August 25, 2020, 06:38:56 PM »
Walrus claimed low Sept ice (we say volume) means high March ice (volume). You chart (and common sense) says the opposite Gero. So how is Walrus right?
I am tired - I re-read the post by Walrus, said bad words,  and edited my post above.

Nevertheless the correlation looks good - but counter-intuitive. I for one, accepted that one might expect a rebound in sea ice after a low minimum, as open water releases ocean heat much more quickly.   

And now the correlation says the reverse.

I suppose I had better do the same exercise using JAXA extent data.
« Last Edit: August 25, 2020, 08:30:23 PM by gerontocrat »
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gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3551 on: August 25, 2020, 07:39:08 PM »
which I have done, using JAXA extent monthly averages, September & the following March deviations from the linear trend.

The result - zilch. No correlation.
The X-Y graph has similar numbers of data points in all 4 quadrants.
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The Walrus

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3552 on: August 25, 2020, 09:32:30 PM »
Gerontocrat,

Plotting by year makes the trend harder to see or measure.  Try plotting the minima on the x axis and the ensuing maxima on the y.  Using all years, the trend is small.  However, starting with the years with low minima (2002), the data points are not clustered equally throughout the four quadrants.  Compared to the trend, 7 years exhibited a lower minima and higher ensuing maxima, 5 showed a higher minima and lower maxima, 4 showed both a lower minima and maxima, and 2 both higher minima and maxima.  Twice as many data points appeared in the quadrants with opposite signs as those with similar signs.  Additionally, of the 9 years with a higher maxima, the 7 highest maxima where all preceded by lower minima.  The lower the minimum, the more likely that the ensuing maximum is higher.


binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3553 on: August 26, 2020, 12:04:58 PM »
I've been playing around with the numbers, but not sure if I'm doing it right.

I've taken the monthly JAXA extent averages for September and the following March, detrended them and plotted against each other, with Sept values on the x axis and March on y.

Below are two very ugly graphs, there seems to be a correlation and it is stronger since the turn of the century. So does this mean that there is a slightly bigger change of a larger maximum following a low minimum?

EDIT: it seems the odobenidae are leading by a whisker
« Last Edit: August 26, 2020, 01:18:54 PM by binntho »
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The Walrus

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3554 on: August 26, 2020, 01:54:04 PM »
Binntho,
That is similar to what I have gotten.  My answer is that there is a slightly bigger chance of a larger maximum following a low minimum.  I like your wording, so I am going with it.

This was the question that Colding asked originally, and many responses did not address the question.  I agree with those posters that higher minima have no reflection on the following maxima, but that was not the question posed.  The scientific evidence points to open water losing more heat that ice-covered, but is it enough to overcome the extra heat added?  The data is inconclusive (or ugly), but does point in that direction.  If next March, the maximum is slightly higher again, then we have one more data point in support.  If not, then the opposite.

Thank you for your comment, but I admit that I had to consult my dictionary.

binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3555 on: August 26, 2020, 02:29:38 PM »
...  but I admit that I had to consult my dictionary.
"walking by their teeth" is the literal meaning, referring to the way they use the tusks to help them crawl forward on ice or dry land.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

Glen Koehler

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3556 on: August 26, 2020, 04:42:04 PM »
<snip>I've taken the monthly JAXA extent averages for September and the following March, detrended them and plotted against each other, with Sept values on the x axis and March on y.

Below are two very ugly graphs, there seems to be a correlation and it is stronger since the turn of the century. So does this mean that there is a slightly bigger change of a larger maximum following a low minimum?
     Walrus was correct that I addressed the wrong issue in my previous post.  Perhaps a saving grace in my misdirected response is that regardless of the Sept. minimum's influence on the following March maximum, it really does not matter in the big picture because that March max has essentially no correlation with the NEXT Sept minimum.  But whether Sept affects the following March is of interest for understanding ice dynamics even if there is no long term effect, so pointing out the lack of long-term effect is really just to make me feel a bit less useless.

     Face-saving aside, I feel compelled to point out that with an R2 of 7% from a small number of data points the conclusion that there is a trend to discuss is a Hail Mary pass (if binntho can use an obscure scientific term, I can use one from American football) based on statistical noise.  In other words, that slope is almost certainly very far short of statistical signficance.  (binntho your graphing software probably either gave you a direct measure of significance or the variance needed to calculate it.  Sharing it would be informative.)
   
     Moreover, the visually imagined "trend" is highly leveraged by two data points on the extreme ends of the X axis.  Take either one of those points out and there is almost nothing trendy left (not that there is much in the complete set of data points anyway).  Take both out and what's left is the a classic example of random distribution.  There are procedures to identify and justify removal of overly leveraged data points.  I doubt either of those two points is egregious enough to meet those criteria, so this comment is reverse cherry picking.  But it's not nit picking.  Just because a trend line from a small set of data points has a slope does not mean that it indicates anything real.  Noise is more real than signal in such cases.  At least until one shows a numerical test of significance.  The human eye is really great at seeing things that are not there (e.g. the face on Mars etc.) 

      As for the orginal question, I think that for now we can conclude that we don't know, and won't know until we have 20 mores year of data.  At which point the Arctic will be so different that we will have to throw out the first 20 years of data and start over.
« Last Edit: August 27, 2020, 04:40:09 PM by Glen Koehler »

binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3557 on: August 26, 2020, 05:16:29 PM »
Glen, my statistical expertise is not signifcant although it has been trending upwards in the last few years.

I downloaded the JAXA CSV file, ran a program on them to get a two colum CSV with september average in the first column, following march average in the second column. This I then pasted into Excel.

Following this I detrended by the simplest method - taking the difference from one value to the next. Lastly I made a scattergraph and asked Excel to show the trendline, the equation and the R2 value.

To be honest, I have absolutely no idea how reliable, or even how real, this result is. But tentatively I suggested that perhaps it indicated that there was a slight change of a higher maximum following a lower minimum.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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The Walrus

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3558 on: August 26, 2020, 05:45:15 PM »
Glen,

I think we may have exhausted this topic for the time being.  We seem to be agreeing that there is a slight trend, but that it may not be real.  Any correlation may be small compared to other, longer term effects.  By the way, using the same data starting with the then-record low of 2002, the R2 was 24%.  Still nothing to write home about, but the Hail Mary can be thrown from a few yards closer.  Thanks for your posts.

karl dubhe2

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3559 on: November 03, 2020, 03:24:15 PM »
Finally found this thread again.  :)  I've a question, that might be both.   Although I'm a bit hesitant to ask, as it might infringe on the chemtrail nuttery.   

I was wondering what effect the lower number of trans-Arctic flights has had on the ice this last year?   Fewer aircraft flying over the pole would result in a bit less water vapour and CO2 up there, right?   Or that's what I'd suspect anyhow. 

Phil.

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3560 on: November 03, 2020, 05:07:29 PM »

oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3561 on: November 04, 2020, 03:22:55 AM »
There was a thread earlier this year that attempted to discuss this issue. It did infringe on the chemtrail nuttery though. Still you might find some useful stuff there, and perhaps add your own thoughts.

https://forum.arctic-sea-ice.net/index.php/topic,3181.0.html

Tom_Mazanec

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3562 on: November 05, 2020, 11:17:33 PM »
Here are a couple:
1) Is arctic sea ice frozen salt water and icebergs frozen fresh water?
2) How do we measure sea ice extent/area from space through clouds? I thought radar, but then remembered radar storm pictures, so I guess radar doesn't go through clouds?
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oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3563 on: November 06, 2020, 03:32:44 AM »
Arctic sea ice is frozen seawater with some of the salt excluded during the freezing process, and more of it excluded as time goes by. Icebergs are made of snow compressed under its own weight into freshwater ice.

Ice remote sensing is done via a passive microwave radiometer, meaning the satellite scans several frequencies for the typical emissions of ice.

http://www.remss.com/missions/amsr/

Quote
The Advanced Microwave Scanning Radiometer...

We have processed data from all these instruments to provide the typical RSS microwave radiometer ocean measurement product suite consisting of: Sea Surface Temperature(SST), Surface Wind Speeds (low and medium frequency), Atmospheric Water Vapor, Cloud Liquid Water, and Rain Rate.

A key feature of these AMSR instruments is the ability to see through clouds, thereby providing an uninterrupted view of ocean measurements.

The AMSR instruments are dual-polarized, conical scanning, passive microwave radiometers.  Each is placed in a near-polar orbit which allows for up to twice daily sampling of a given Earth location.  The eight instrument channels are summarized in the following tables.

We use an on-orbit calibration method developed by RSS to convert counts to brightness temperatures.

ReverendMilkbone

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3564 on: December 28, 2020, 08:42:43 PM »
How is the SSW/polar Vortex prediction from Severe-weather-EU playing out?

https://www.severe-weather.eu/global-weather/stratosphere-major-winter-warming-watch-january-2021-fa/

Glen Koehler

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3565 on: January 19, 2021, 03:36:05 PM »
     Are there different terms/names to distinguish between
1) broad retreat of CAB ice along the Atlantic front interface with Greenland, Barents, and Kara Seas
vs.
2) Atlantic water intrusion along the Siberian coast, now reaching into the ESS and perhaps the Chukchi Sea?

     My understanding is that "Atlantification" refers to #2.  If so, what is the name for #1?
"CAB-Atlantic side retreat"?

     Whatever it is called, the Atlantic side of CAB looks weak at present.  But in previous cases, Arctic variability has led me to believe that a large change was underway only to see the ice revert closer to "normal" later.  And even if Atlantic side of CAB is weak at present, there are 2-3 months of strong freezing and ice increase remaining this winter.  And last time I looked, the CAB volume statistics did not seem remarkably low. 

     Of course, the long term trend downward to less ice is indisputable.  But for today, the question is does the current amount, thickness and/or concentration of ice in the CAB along the Atlantic front appear to be significantly different from previous recent years?
« Last Edit: January 19, 2021, 07:14:47 PM by Glen Koehler »

gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3566 on: January 19, 2021, 04:47:21 PM »
     Are there different terms/names to distinguish between
1) broad retreat of CAB ice along the Atlantic front interface with Greenland, Barents, and Kara Seas
vs.
2) Atlantic water intrusion along the Siberian coast, now reaching into the ESS and perhaps Chucki Sea?

     My understanding is that "Atlantification" refers to #2.  If so, what is the name for #1?
"CAB-Atlantic side retreat"?
Atlantification originally was a term used specifically for the transition of the Barents Sea from cold, fresh Arctic waters to a warm, salty Atlantic regime.
https://www.carbonbrief.org/atlantification-arctic-sea-tipping-towards-new-climate-regime
https://www.nature.com/articles/s41558-018-0205-y.epdf


But it is often used more generically (and I am one of the culprits) to refer generally to the increasing influence of the Atlantic Ocean on the Arctic. And that includes warmer saltier water from the Atlantic pushing further along the Siberian coast, which Uniquorn amonagst others tracks for us.

As for the general retreat along the Atlantic front, is there a generally accepted name? I usually talk about retreat from and advance to 80 North along the Atlantic Front- in 2020 85 North.

But everything is temporary - in 50 years the Arctic Ocean may be no more - the Arctic Sea merely a part of the North Atlantic Ocean.
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binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3567 on: January 20, 2021, 11:29:50 AM »
     Are there different terms/names to distinguish between
1) broad retreat of CAB ice along the Atlantic front interface with Greenland, Barents, and Kara Seas
vs.
2) Atlantic water intrusion along the Siberian coast, now reaching into the ESS and perhaps Chucki Sea?

     My understanding is that "Atlantification" refers to #2.  If so, what is the name for #1?
"CAB-Atlantic side retreat"?
Atlantification originally was a term used specifically for the transition of the Barents Sea from cold, fresh Arctic waters to a warm, salty Atlantic regime.
https://www.carbonbrief.org/atlantification-arctic-sea-tipping-towards-new-climate-regime
https://www.nature.com/articles/s41558-018-0205-y.epdf


But it is often used more generically (and I am one of the culprits) to refer generally to the increasing influence of the Atlantic Ocean on the Arctic. And that includes warmer saltier water from the Atlantic pushing further along the Siberian coast, which Uniquorn amonagst others tracks for us.

Personally I would like to see the term "Atlantification" being used to describe what the word implies, i.e. when a patch of ocean takes on the general aspects of the Atlantic, and has thus been Atlantified.

Intrusion of warm waters along the Siberian coast is not Atlantification. I rather doubt that the Siberian seas can be Atlantified at all, given how shallow they are.

And as for Glen's question, his number 1 has more to do with the ongoing Atlantification of the Barents and possibly even parts oft the Kara. I'm not sure what he means by the "retreat of CAB ice along the Atlantic front interface with Greenland ...". Where is this to be found more precisely?

His number two should presumably be called "Atlantic water intrusion", I see no need for mongrelizing other words to describe what can be described perfectly by calling it what it is.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Glen Koehler

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3568 on: January 28, 2021, 02:45:21 PM »
<snip> I'm not sure what he means by the "retreat of CAB ice along the Atlantic front interface with Greenland ...". Where is this to be found more precisely?
    The edge of the CAB where it meets the Greenland, Barents, and Kara seas.  'CAB-[name of sea] peripheral retreat" would suffice if it needs a name.

     I stand corrected on "Atlantification" and agree that "Atlantic water intrusion" is a good name for that phenomenon. 
« Last Edit: January 28, 2021, 02:52:23 PM by Glen Koehler »

binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3569 on: February 01, 2021, 06:13:27 AM »
<snip> I'm not sure what he means by the "retreat of CAB ice along the Atlantic front interface with Greenland ...". Where is this to be found more precisely?
    The edge of the CAB where it meets the Greenland, Barents, and Kara seas.  'CAB-[name of sea] peripheral retreat" would suffice if it needs a name.

Thanks for the clarification.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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uniquorn

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3570 on: February 09, 2021, 04:49:20 PM »
It's generally accepted that anti-cyclonic winds cause ice to move towards the centre (ice to right of wind) sometimes described as compaction or compression.

What is the effect on the water beneath the ice?

crandles

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uniquorn

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3572 on: February 09, 2021, 08:05:52 PM »
What is the effect on the water beneath the ice?
https://en.wikipedia.org/wiki/Ekman_transport#Ekman_pumping

Quote
The third wind pattern influencing Ekman transfer is large-scale wind patterns in the open ocean.[1] Open ocean wind circulation can lead to gyre-like structures of piled up sea surface water resulting in horizontal gradients of sea surface height.[1] This pile up of water causes the water to have a downward flow and suction, due to gravity and the concept of mass balance. Ekman pumping downward in the central ocean is a consequence of this convergence of water.[1]

Also found this:
https://www.researchgate.net/publication/5415676_Comment_on_EddyWind_Interactions_Stimulate_Extraordinary_Mid-Ocean_Plankton_Blooms#pf2

gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3573 on: February 10, 2021, 07:55:55 PM »
Lots of stuff you can find out about conseuences when we have an SSW.

But what happens if there is a Sudden Stratospheric Cooling?
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kassy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3574 on: February 11, 2021, 12:07:30 AM »
But what happens if there is a Sudden Stratospheric Cooling?

This must be a theoretical question since we don´t have them. Heat seeks cold. SSWs are heat bubbles going to the pole from lower latitudes. You cannot have cold bubbles rising and doing that.

In fact look at the other side. Imagine a world about to go into an ice age. The effect is local and albedo driven. Once you establish year round ice it grows from there.
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gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3575 on: February 11, 2021, 01:39:01 PM »
But what happens if there is a Sudden Stratospheric Cooling?

This must be a theoretical question since we don´t have them. Heat seeks cold. SSWs are heat bubbles going to the pole from lower latitudes. You cannot have cold bubbles rising and doing that.
The Japanese Meteo Agency says..
The Stratospheric Sudden Warming (SSW) is a phenomenon characterized by a rapid increase in polar temperatures in the stratosphere.
i.e. the SSW is defined by the symptom, not by the cause as described by Kassy, nor by the effects that perhaps we are seeing now.

There has been a sudden stratospheric cooling. (See image attached). 10 hpa temperatures have dropped by 30C to well over 15 C below average in the last few days. So I ask the same question: what is the cause and what might be the effects, especially if 10 hpa temperatures drop even more and 30 hpa temps drop as well?

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/readme.html
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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3576 on: February 11, 2021, 03:01:58 PM »
Does the graph just show a brief SSW and then as it returns to normal there is a lot of noise as it does so? Not sure that should or could be called a SSCooling. I might be more convinced if the data was near trend then took a plunge.

Alumril

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3577 on: February 15, 2021, 04:45:05 PM »
Nitrous Oxide in 2020.

I was looking at the N2O trend at the Barrow Observatory and noticed the 2020 figures followed a much straighter trend than the more wavy trend of previous years.
Mona Loa is similar, South pole looks like its been doing this for the last 2 years.

Is it due to better equipment / methodology or is there another reason for the tighter data sets?

Appreciate it someone can point me in the right direction.


Stephan

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3578 on: February 15, 2021, 05:05:23 PM »
Could you re-post this thread in the Science\Trends in atmospheric N2O thread? It is better discussed there.

I tried to follow your screenshot but I was unable to create the graph you show. Could you send me a link to that, so I hopefully can answer.
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binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3579 on: February 16, 2021, 05:34:48 AM »
Regarding Fram export during winter: Another poster said something along the lines of "without any Fram export the Basin will fill with ice" which got me thinking: What is the real net contribution of Fram export during the freezing period?

When ice is exported through the Fram strait it leaves gaps in the ice pack within the basin proper. These gaps freeze over very fast, propably reaching half a meter or a meter within a few weeks. So the ice lost is replaced fairly quickly, with the addendum that exra ocean heat is lost through the gaps.

So as long as mostly first year ice is exported I'd guess that the net effect of Fram export is in fact very low during the freezing season - and even negative through two mechanisms:

1) The gaps that open up, even if fleetingly, in the basin itself lose extra ocean heat that would otherwise have been able to contribute to melt in the summer.

2) And secondly, Fram export through winter causes a colde winter climate further south which might concievably effect heat advection up the Northern Atlantic.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3580 on: February 16, 2021, 05:54:14 AM »
The problems are:
* It's not only or mostly FYI being exported. A lot of the exported ice comes from the vicinity of the Pole and is often MYI.
* Even if FYI is exported, the thickening from October is not the same as thickening from December or February or whatever the export date is. So full FYI being replaced by half FYI weakens the ice pack.

2020 began with a massive and sustained export event from the region between the Pole and the Lincoln Sea, around February-March, as can be seen in Ascat and other animations posted at the time. I am sure this had a serious effect on the ice pack and on the resulting melting season.

binntho

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3581 on: February 16, 2021, 07:17:06 AM »
The problems are:
* It's not only or mostly FYI being exported. A lot of the exported ice comes from the vicinity of the Pole and is often MYI.
* Even if FYI is exported, the thickening from October is not the same as thickening from December or February or whatever the export date is. So full FYI being replaced by half FYI weakens the ice pack.

2020 began with a massive and sustained export event from the region between the Pole and the Lincoln Sea, around February-March, as can be seen in Ascat and other animations posted at the time. I am sure this had a serious effect on the ice pack and on the resulting melting season.

All of which sounds very reasonable. But I am a longstanding suffererer from repeated attacks of contrariness, which at times makes me think that even the most reasonable line of reasoning sounds like "we have no idea, so let's turn it into an axiom and stop thinking about it".

So even if I am willing to accept, on basis of intuition and arm-chair reasoning, that Fram export is mostly on balance a negative feedback to the health of the ice, I still cant help but wonder if in reality it makes any difference at all. Is there any correlation between Fram ice export during winter and the following melt season? Has anybody checked? I'm too busy just now, but perhaps later.
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Freegrass

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3582 on: February 16, 2021, 01:23:32 PM »
Is there a significant effect on salinity with more or less Fram export? If a lot of ice gets exported through Fram strait, it takes a lot of fresh water with it, no? And if all that ice stays in the basin, salinity in the basin should drop a little, right?
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oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3583 on: February 16, 2021, 03:01:41 PM »
Binntho, nothing is cast in stone. You may be right, Fram export has several facets, including cooling the Greenland Sea as well as drawing ocean heat content up in the Arctic. However, my intuition tells me more export is worse than less export, especially if the feeding region comes from the left (Pole, Lincoln) rather than from the right (FYI from direction of Laptev, Kara).

FG, I don't know.

kassy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3584 on: February 16, 2021, 04:32:50 PM »
Is there a significant effect on salinity with more or less Fram export? If a lot of ice gets exported through Fram strait, it takes a lot of fresh water with it, no? And if all that ice stays in the basin, salinity in the basin should drop a little, right?

New ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone.


https://nsidc.org/cryosphere/seaice/index.html

So i don´t think it matters that much since it is mostly multiyear ice getting exported.

Also if you consider it is sea ice. So local Arctic salt water freezes:

In contrast to fresh water, the salt in ocean water causes the density of the water to increase as it nears the freezing point, and very cold ocean water tends to sink. As a result, sea ice forms slowly, compared to freshwater ice, because salt water sinks away from the cold surface before it cools enough to freeze. Furthermore, other factors cause the formation of sea ice to be a slow process. The freezing temperature of salt water is lower than fresh water; ocean temperatures must reach -1.8 degrees Celsius (28.8 degrees Fahrenheit) to freeze. Because oceans are so deep, it takes longer to reach the freezing point, and generally, the top 100 to 150 meters (300 to 450 feet) of water must be cooled to the freezing temperature for ice to form.

This sunken cold salty water is a protective layer for ice and the important bit for Arctic salinity.

We can also answer the question is there a significant effect on salinity with more or less Fram export in a general way.

All icebergs ever exported fresh water in a solid state from the Arctic. Did this ever do anything to salinity in the basin? I don´t think so.

The main reason why we watch the upper part is to check on the halocline.
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Something about hurricane energy and Arctic sea ice?
« Reply #3585 on: February 17, 2021, 07:01:03 AM »
Hi, I have read that hurricanes act as, in essence, a natural heat pump that redistributes large amounts of heat energy from lower latitudes to higher latitudes.
Disregarding cyclonic storms that exist around the Arctic, I'm curious if there are any discernible impacts from Atlantic hurricane seasons (higher season ACE) or even from large individual storms on the concurrent melt or freeze conditions in the Arctic?
Any ideas? Thanks!

oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3586 on: February 17, 2021, 05:03:04 PM »
Welcome, Jamesmustain. I have moved your question here, to avoid the creation of another thread.

SimonF92

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Re: Something about hurricane energy and Arctic sea ice?
« Reply #3587 on: February 17, 2021, 05:25:19 PM »
Hi, I have read that hurricanes act as, in essence, a natural heat pump that redistributes large amounts of heat energy from lower latitudes to higher latitudes.
Disregarding cyclonic storms that exist around the Arctic, I'm curious if there are any discernible impacts from Atlantic hurricane seasons (higher season ACE) or even from large individual storms on the concurrent melt or freeze conditions in the Arctic?
Any ideas? Thanks!

Hi Jamesmustain. Anecdotally, whenever the cyclone cannon blows something up toward the barents/kara sea in Autumn/Winter there will be a recession in the new ice forming there- this happens every year to a greater or lesser extent. So I guess tail-end storms of the hurricane season could directly affect ice formation. However, normally the ice surges back to where it was displaced from fairly quickly.

Regarding impacts in June-September, peak hurricane season- they might not be so obvious on the satellite images but any wind/wave driving over the melting pack is surely going to be damaging- both from motion increasing fragmentation/dispersion and by driving thermocline mixing.

Every year someone will call a GAC, a 'great-Arctic-cyclone', which is apparently the harbinger of death for the ice, but it never quite goes like that
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gerontocrat

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3588 on: February 18, 2021, 02:53:48 PM »
But what happens if there is a Sudden Stratospheric Cooling?

This must be a theoretical question since we don´t have them. Heat seeks cold. SSWs are heat bubbles going to the pole from lower latitudes. You cannot have cold bubbles rising and doing that.

There has been a sudden stratospheric cooling, if it can be defined by the data, i.e. suddenly to well below average, and causing a change in wind patterns. (See images attached).

10 hpa temperatures dropped very quickly by 30C to well over 15 C below average and have stayed down in the last few days.

The effect has reached down to 30 hpa. Temperatures have dropped plunged to around 7+ degrees below average for the time of year.


So I ask the same question: what is the cause and what might be the effects, especially as 10 hpa temperatures have stayed down and 30 hpa temps have dropped as well?

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/
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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3589 on: February 20, 2021, 07:11:43 PM »
So I ask the same question: what is the cause and what might be the effects, especially as 10 hpa temperatures have stayed down and 30 hpa temps have dropped as well?
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/
No idea but here is a comparison of 10hPa and 30hPa Zonal temps. 1979-2021 sep-feb.
A lot of variation over the years.

Aluminium

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3590 on: February 21, 2021, 05:31:51 PM »
Has the Gulf of Mexico any ice in history?

kassy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3591 on: February 21, 2021, 06:47:58 PM »
This is a reply to Gerontocrats query in #3588 from the melting season thread.


Elsewhere I have seen that a colder stratosphere tends to favour a stronger polar vortex.

But the fact remains that temps at 10hpa are about 20C below average, and 10C below average at 30hpa. This is at a time when rapid temp increases is the norm. Has anybody any thoughts on the effect of a "sudden stratospheric cooling" on lower altitudes?

I know nothing about this but I guess the current cooling is due to the polar vortex finally "restarting" after having collapsed spectacularly in January (and it stayed collapsed for unusually long). So it is a sort of pendulum-effect: it was down and out for long so it returned in strength.
Now a strong vortex favours ice retention if I am correct BUT with the current extreme heat intrusion into the North Pole region that might not be true.
Anyway, the Pole-region seemed very vulnerable even before this event and now looks even more so.
So, as I said I know nothing.

First of this is as stated a laymen opinion but this is my line of thinking too. The question is actually interesting but actually we cannot answer it with current graphs alone. Is this uncommon? Ideally you need graphs from a whole bunch of events.

The temps first spike up to temps higher then SEP. Would be interesting to see the same graph with the priors year(s). Or plotting the general downtrend after spikes etc.

Short version: a work in progress i guess.  ;)

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crandles

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3592 on: February 21, 2021, 07:29:38 PM »
Has the Gulf of Mexico any ice in history?

any ice?
I am sure someone will have spilt a cocktail  ;) ;D

before the Late Triassic, the Gulf of Mexico did not exist (~200Mya)
https://en.wikipedia.org/wiki/Gulf_of_Mexico#History

The Snowball Earth hypothesis proposes that during one or more of Earth's icehouse climates, Earth's surface became entirely or nearly entirely frozen, sometime earlier than 650 Mya (million years ago)
https://en.wikipedia.org/wiki/Snowball_Earth

Last glacial maximum seems the coldest in last 200 million years.
https://en.wikipedia.org/wiki/Timeline_of_glaciation


https://en.wikipedia.org/wiki/Quaternary_glaciation

doesn't suggest it gets that far south, but I assume that is glaciation and there is likely to be several particularly cold winters during that period so I would suggest some temporary sea ice might well be possible but I have no idea really.
« Last Edit: February 21, 2021, 07:38:34 PM by crandles »

kassy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3593 on: February 22, 2021, 04:33:29 PM »
To the picture you can also add the waters flowing in:
https://en.wikipedia.org/wiki/North_Equatorial_Current

I am pretty sure it never got cold enough there for sea ice to form.
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Tony Mcleod

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3594 on: February 25, 2021, 11:15:02 AM »
Can someone help me with the question of thermal flux into the Arctic? How much is oceanic versus atmospheric? I can vaguely remember they both contribute but I can't find a link to it.

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3595 on: March 10, 2021, 04:31:00 PM »
The most recent in the current sequence of cyclones appears to have bottomed out with a central MSLP of 960 hPa according to Environment Canada:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-10

Quote
By way of comparison note that the “Great Arctic Cyclone” of August 2012 reached a minimum MSLP of 966 hPa.
      960 in the summer would be a huge impact.  What effect does it have near the peak of winter refreeze?  This is not a leading question, I truly have no clue and am wondering.

     I don't see how a winter storm over continuous ice cover would stir up much subsurface heat.  I suppose it can move the ice around, but with a continuous ice cover how much traction does the wind get with a relatively smooth surface?  I suppose strong winds create ridging even from continuous ice cover, and that the ridging of course creates area of thicker ice.  But the ice piled into ridge is at the expense of area from whence the ridged ice came.  What is the net effect of a winter low pressure system on the ASI?

oren

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3596 on: March 10, 2021, 06:24:29 PM »
I think it mostly results in breakup and some transport. Any new leads opened cause some thin ice gain. At this late stage of winter I would assume it weakens the ice more than it strengthens it overall.
Check out uniquorn's post in the Home Brew thread. I believe the "lift off" was a result of the cyclone.
https://forum.arctic-sea-ice.net/index.php/topic,382.msg302611.html#msg302611

Jim Hunt

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3597 on: March 10, 2021, 07:27:55 PM »
What is the net effect of a winter low pressure system on the ASI?

In this case the most obvious effect is the opening up of this "crack" in the East Siberian Sea:
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Glen Koehler

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3598 on: March 11, 2021, 08:39:45 PM »
Hanging around waiting for the melting season to start is.....Boring!         
     I doubt anyone would disagree that melt season is more exciting, but there is something to chew on in this waning freezing season.  The total JAXA Extent increase since September minimum for 2020-2021 freezing season at 10.68 km2 is tied for 2nd place with 2007-2008.  The gain since minimum is more than 10% above all other years except for good ole 2012-2013 in 1st place at a seemingly unreachable 11.29 km2.

     It is easy to understand how a low September minimum sets the system up for a large amount of winter refreeze gain.  But the degree to which the ASI maximum returns to an almost homeostatic level for winter maximum is impressive nonetheless.
 
     The "Slow Transition" folks are probably feeling pretty smug right now.  I'm more of the "We're on the edge of cataclysm" tribe myself.  So I wonder if these compensatory rebounds are about to run out of steam as qualitative changes in the Arctic erode the system from the inside out.  I would like to be wrong about this.  While we wait for the starting gun on melt season, comments and civil arguments welcomed about what the strong 2020-2021 freezing season tells us.
« Last Edit: March 11, 2021, 10:34:32 PM by Glen Koehler »

kassy

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Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« Reply #3599 on: March 11, 2021, 09:02:19 PM »
What if you plot all the extents vs the long term volume plot?
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