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Messages - Pagophilus

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1
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 03:28:45 AM »
Most of the southern ESS, from the coast to about 200 - 300km towards the pole, is now a mass of loose floes, in some places with significant open water.   And then a close-up.   Top image unaltered, bottom pushed for contrast on Photoshop.  It seems to be happening scarily fast.

Off (and off-line) to the mountains for a few weeks... back in Sept.  May the ice be with us...

2
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 06:27:36 PM »
Those rhomboid shaped floes is where PIOMASS sees thick, MYI, some of the thickest ice left in the CAB.
Given the location of much of that thicker ice, and given the fact that there has been much clockwise rotation of the main pack towards the Atlantic, it would follow that ice has been piling up on the poleward side of these islands for some time.   

I therefore cannot help wondering whether the extra thickness on the poleward sides of these islands is at least partly caused by extensive ice ridging in these areas thickening the ice rather than by MYI somehow occurring in relative isolation in these three areas.

3
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 06:04:39 PM »
Beautiful Worldview imagery of the Kara/Barentz today.

Rapidly melting 'rubble' ice in the N/E Kara Sea.  A little bit of (wind compacted) ice left in the S/W Kara Sea.

Streamers of melting ice coming off the remaining ice in the S/W Kara Sea (E Novya Zemlya in frame)

Sharp edges of wind-concentrated ice on the shrinking tongue of ice extending from E of FJL into the Barentz (winds came from the S) contrasting with the more ragged leeward side.  This must have reduced the AMSR2 extent figures a bit, given the other ice tongue was subject to the same winds.

The ice tongue off Svalbard is also almost gone (last image).

The Barentz may now start warming up more?

4
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 05:49:08 PM »
I doubt the 80N band remains saved from the onslaught, perhaps enjoying a temporary relief, by the SMOS map is pretty clear
Holy smoking toledos.  If the ice is that liquid on top, and the situation continues, then the subtler processes of melting (general ongoing energy input from above and below) may be all that's needed, no big storm/weather event drama required.  :o

5
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 02:22:33 AM »
Consider it fate, but Gerontocrat posted the daily extent losses for July 2012 on the data thread today. You'll see a couple of intervals of serious losses there as well.

Motivated by your graph, attached is NSIDC extent for July 4 2019 compared with Aug 4 2012.  It gives an idea of what would have to melt out for in the next month to keep pace with 2012.  It looks pretty feasible to me, but others have way more experience.

6
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 02:00:55 AM »
Laptev fast ice breaking up with great rapidity in the region of the Lena Delta.

The fast ice nearer the delta broke up extensively about a week ago (it disappeared long ago right next to the delta).  The ice now breaking up in the image was spotted by grixm yesterday.  Today, there are many more cracks in this area, which to me indicates ice that has passed a certain threshold of integrity and thinness.  Melting may be rapid from here.
July 8 Nullschool forecast, surface winds and temps.

Looking somewhat toasty for the ESS...

For both reasons, I think that the Northern Sea Route will open earlier this year. End of July? On the middle of july (10th. to 20th.)? Beginning of August? Any bets?

I see what you mean.  There is already almost a route there to be threaded from the Atlantic through the Laptev, with the only big obstacle being the ESS... That is a lot of ice though.  I have absolutely no idea really, but what the heck ... first week of August.

7
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 01:51:00 AM »
The fast ice nearer the delta broke up extensively about a week ago (it disappeared long ago right next to the delta).  The ice now breaking up in the image was spotted by grixm yesterday.  Today, there are many more cracks in this area, which to me indicates ice that has passed a certain threshold of integrity and thinness.  Melting may be rapid from here.
Do you think we will be able to use the upcoming piomas data to get the threshold where sea ice breaks apart this season?

An interesting idea!  Maybe this would be done retrospectively first... where did ice break up in the past and what was Piomas 'saying' at that point?  Are there correlations with indicated Piomas thickness and time of fracturing?
   
But all in all, I would be hesitant, since Piomas is modeled, not measured, and its output has a general quality to it (as would be expected).  And I imagine so much probably depends on ice quality as well as thickness when it comes to ice breaking up.  And also, are we maybe talking about fast ice in your question, because much of the pack ice is already pretty rubbly already?  Having shot my mouth off (something of a problem I regret to say) I now step aside and let the experts take charge.

8
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 01:41:32 AM »

Looking somewhat toasty for the ESS...

If Climate Reanalyzer is even close on its 3 day maximum temperature forecast, it will be more than toasty.

I couldn't find an understatement emoji...      ;)

9
Arctic sea ice / Re: The 2019 melting season
« on: July 05, 2019, 11:23:29 PM »
July 8 Nullschool forecast, surface winds and temps.

Looking somewhat toasty for the ESS...

10
Arctic sea ice / Re: The 2019 melting season
« on: July 05, 2019, 11:18:58 PM »
Laptev fast ice breaking up with great rapidity in the region of the Lena Delta.

The fast ice nearer the delta broke up extensively about a week ago (it disappeared long ago right next to the delta).  The ice now breaking up in the image was spotted by grixm yesterday.  Today, there are many more cracks in this area, which to me indicates ice that has passed a certain threshold of integrity and thinness.  Melting may be rapid from here.

11
Arctic sea ice / Re: The 2019 melting season
« on: July 05, 2019, 01:14:01 AM »
Looks like the Laptev fast ice is finally shattering fully. On the latest worldview shot you can see massive cracks everywhere there isn't clouds

grixm, nicely spotted!  It is a significant development.  I took a screenshot and bullied it around in Photoshop to bring out the cracks and 'see' through the clouds better.  Hope you don't mind. The extensive cracking of a huge area of fast ice is, I hope, even more visible.  Unlike the recent breakup of fast ice in the ESS, where there was nowhere for the ice to go, these floes can probably easily migrate into what is now a huge Laptev bite, filled with warmer water.

BTW, the ice is not really that blue... I pushed saturation in Photoshop to make the cracks stand out.

12
Arctic sea ice / Re: The 2019 melting season
« on: July 04, 2019, 12:05:19 AM »
June 28 - July 2.

2018.

These animations are, as usual, terrific.  Thanks.  The ice front is so visibly retreating on both the Atlantic and Pacific sides, and most particularly on the Pacific side, as several have noted.  Heat continues to flow in there, and ice continues to exit the Fram.  The Nullschool July 7 surface wind forecast favors both processes carrying on until at least then.  The shrinkage of the pack over just 4 days comes across powerfully.  Sometimes the weather does not have to be super-dramatic, just consistent, for significant changes to happen.   

13
Arctic sea ice / Re: The 2019 melting seas
« on: July 03, 2019, 11:40:39 PM »
As far as forecast interpretation, Michael’s one was not that outlandish (it’s a tad cooler) and Friv stopped posting, which correlates well with the change of weather.
That as long as outlandish is not “out of what the tribe thinks”.

+1      As long as a poster can back up their ideas and predictions with reasonable evidence and logic, then in my view they should be allowed to post without personal harassment.  If you disagree with someone, then debating that is one of the ways that science progresses -- just make the argument, not the accusation.   

14
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 06:42:26 PM »


Huge export of ice coming down into the Fram (I wonder how much of that is MYI).



Far less than in years past as there is far less MYI to export.

Good to have this experienced perspective.  It is also true, is it not, that the less MYI remains in the CAB, the more significant the loss of that remaining MYI becomes?

15
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 05:57:43 PM »

Ice south of the Fram is still counted in extent, area and volume regardless of whether it has a shipping label on it or not.
True but I think people are looking forward to the immediate future when talking about dispersion and ice export. The life expectancy of ice depends on where it is ? It is reasonable to assume that in July open water created in the CAB, for example, by Fram export will not freeze over, while the ice sent down the Fram is doomed to die pdq.

This is a problem that comes up over and over in science and in almost any discussion.  I think much can be clarified by people first defining the system they are analyzing.  So, if we define the system/area we are discussing as the CAB, then it becomes clear that spreading of ice in the CAB can be said to be dispersion, and ice spreading out the CAB can be said to be export.

16
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 05:48:08 PM »
So I was playing with the various tools trying to quantify in my own mind how likely it is we'll beat 2012 and came up with this... this is ice today vs 2012 one month from now, and then looking at the likely hood those areas will be gone as of a month from now... based on the current concentration on those areas..... and taken in the context of the weather / winds for the next week...and well YIKES! :o 

Please note I'm not saying it'll melt exactly like this and in a month it'll look exactly like 2012, (in fact I highly doubt it), but its very much in the realm of possibility that a lot of the area's that 2012 was missing a month from now is going to melt out to a greater extent in the next month...been mostly lurking here for years, and usually by around this point in the year, I'm starting to relax and think okay, so it probably wont be this year we beat 2012... this year though... exciting times :)

+1   Very nice.  I had not thought about doing future tense stuff in this manner.  Focuses the predictions in at least some direction if 2012 is seen as been similar in some ways to 2019.

17
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 05:40:10 PM »
It seems to me that we have been using the words dispersion and export quite happily for the last several years without having to wrangle about what the words actually specifically mean down in the Bayou.

As someone who speaks English as a second (or even third) language, I am at times amazed at the low quality English used by some of the native speakers on the forum, with grammatical non sequiturs, embarassing spelling mistakes and word salads that would stretch the abilities of the the greatest of sauciers to dress palatably.

Agree with you on many points, but surely getting clear on terms we use helps work against the 'word salad' responses you are writing about.
 
( It's embarRassing, by the way...   ;)    Not that spelling counts a whole lot, as long as the meaning itself is clear, but the irony was a little too delicious to pass over... sorry!)

18
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 03:36:00 PM »
Sea ice concentration, June 17 – July 1

Huge export of ice coming down into the Fram (I wonder how much of that is MYI).

ESS, Laptev, and Beaufort are lighting up.

CAA is continuing to dwindle away.
Thanks again for these vivid, useful animations.

Your emphasis on the Fram export is I think important.  That export is set to continue fairly strongly for the next three days, with winds driving export fading thereafter, but not reversing.  We only 'see' this Fram export on animations such as yours because the ice melts in the Greenland Sea about the same rate as it arrives.

One can almost sense the 'squeezing' of the main pack towards Greenland, and particularly the Fram area on your animation.  Perhaps subjective on my part

The continued disappearance of ice from the Kara and Chukchi, and the ever-wider yawning of the Laptev bite are also notable.  Will upcoming wind patterns send the ice a little more towards the Siberian side and close that yawn somewhat?


19
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 02:53:22 PM »
Pagophilus, I don't want to be snipped by the owner two days in a row so I'll just say, that's the way I understand dispersion vs export as used in this forum, and Fram Export in particular does not generally have to do with dispersion (as understood in this Forum)
I bow to your expertise.  I am just arguing that export, especially Fram export, is (on a system-wide basis) effectively a form of ice spreading out (and becoming more susceptible to melting). 

And I hope you don't get snipped -- I appreciate very much how your comments often go 'against the grain' of general sentiment, making us think more critically.

20
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 02:38:27 PM »
I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)
Here's the Bremen map for the 3rd July 2012.

Thanks for this.  The AMSR2 maps are terrific, but they are also notorious for showing fleeting areas of 'lower concentration', sometimes the result of temporary surface melting due to temporary weather conditions over the ice.  So, as you so effectively show, taking any one AMSR2 map and relying on it to show a long-term trend of the internal condition of the ice pack is risky at best.
 
AMSR2 images usually reliably indicate the boundaries of the ice IMO (although melt ponding can fool the sensors here too), but inferences about the internal condition of the pack usually require more data.   

21
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 02:11:48 PM »
The dispersion used here means "dispersion of the pack in floes separating to each other". The examples we have today is Beaufort and somehow Kara. Caused by storms, usually.
Many examples you bring are called Trasport, or export, ect
A useful clarification.  Thank you.  But I see Rich's point too.
>>I assume transport can just mean ice moving from A to B without necessarily becoming more spread out (dispersed).
>>Export I assume simply means ice leaving the area under discussion. 

But pragmatically, for the Arctic as a whole, doesn't export usually effectively mean dispersion too?  Ice floes spreading apart in the Beaufort and melting because they are separating does not seem much different (to me) than ice floes exiting the Fram and (usually) spreading apart and melting.  Is it not valid to say that the CAB ice that exits the Fram has effectively spread out (dispersed) over a larger area?

I get that the nomenclature has to be carefully applied (and you have helped me with this through your reply) but I think that in essence Rich is correct to raise the other issues.  We need to consider what is happening to the ice overall in terms of its 'spreading out' if we are to get a full picture of this season or any other.   Like Rich I noticed that in arguments above in this thread, the debate centered on melt ponding versus dispersion as indicators of a minimum.  Where does export fit into all of that?

22
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 01:14:15 AM »
June 26-30.

2018.

Thanks once more, Aluminium.  Your gifs show what cannot be adequately seen on Worldview (because of clouds). 

What strikes me is that the forecast strong Fram export is actually occurring apace (and is forecast to continue for three days or so).  That adds up to a lot of ice leaving the CAB.  Much of it MYI.

In addition, the whole Atlantic side now seems be be shrinking back rather alarmingly.   

23
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 07:44:27 PM »

As has been suggested several times already, this is not the appropriate thread, so I have replied in "Re: Arctic Ocean salinity, temperature and waves"

I have noted the suggestion that the threat of warm water pouring through the Bering Strait in 2019 does not belong in the 2019 melting season thread. The GFS is telling us that we should expect this flow to continue for at least 5 days.

If Neven says it doesn't belong here, I'll follow his lead. I'm not inclined to abandon a topic simply because it encounters some resistance nor will I persist simply for the sake of being stubborn.

If someone can prove that there is no risk of substantial amounts of water going over the ice edge, I'll back off.

I can't prove anything, but one of several things that puzzle me here is that, at present, in the Chukchi, there really is no ice 'edge' that I can see on Worldview.  Instead, the 'edge', as far as I can view it, consists largely of myriads of small floes.  These often stretch for about 10-20km before more solid-looking masses of ice (perhaps still floes but in contact with one another/frozen together) are seen in the ice pack.  Perhaps in some limited areas ice could conceivably be rigid and have water flood over it, but in most I would imagine the millions of floes would bob up and down in the water like boats in waves, gradually dampening any surge or other wave motion.   

24
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 03:03:02 AM »
Current forecast continues to be for improved conditions for ice retention.

Perhaps it is worth mentioning of the Atlantic margin of the ice, where the map you posted shows a generally strong positive temperature anomaly.
   
>>  3 day forecast is for winds that ensure sturdy export of ice through the Fram Strait. 
>>  Continued warm winds are forecast to keep entering the Kara Sea, which is rapidly becoming mostly open water. 
>>  The forecast winds will also favor the dispersal and therefore eventual melting of the ice tongues that extended into the Barentz.  These are becoming more attenuated already.




25
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 09:59:35 PM »
My impression from multiple expert posters is that it was the GAC of 2012 that mixed warmer waters up to the surface that provided the heat for the extraordinary melting that lead to the record low.  This was of course primed by the melt-ponding that you mention, but without the GAC, 2012 may have had a low ice minimum, it would not have been a record low.

I'm quite sure the records would have been broken big time anyway (see here). Maybe this year will allow for a comparison, if it can keep up for a few more weeks with 2012, and there is no GAC during August.

Just read the blog post you reference.  Thank you, and thanks for the response on N. Atlantic temps.  csnavywx, I also understand now where you were coming from.   I am now much better informed, and I also definitely have that 'the more you know the more you know you don't know' feeling (again).

It is a sobering thought that an extreme weather event may not be required for a new record low. 

26
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 30, 2019, 09:46:22 PM »
The High Arctic Seas graphs attached.
Poised for stardom? or mediocrity?

Definitely star quality.  Just needs the right agent. 

27
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 09:29:29 PM »
2012 transitioned to a much cloudier and cooler pattern after the 13th or so and never did get the raging dipole pattern again after that, yet the damage was largely done by that point and pack-wide ponding resulted comfortably in a new record anyhow.

My impression from multiple expert posters is that it was the GAC of 2012 that mixed warmer waters up to the surface that provided the heat for the extraordinary melting that lead to the record low.  This was of course primed by the melt-ponding that you mention, but without the GAC, 2012 may have had a low ice minimum, it would not have been a record low.  Maybe you intended this to be understood, or maybe there is something I am missing here...

28
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 09:18:18 PM »
I've taken some time out today to write a very extensive blog post on current events in the Arctic: June 2019, one hell of a month.

Conclusion:

Quote
In recent years, the Arctic has dodged bullets and cannonballs. It looks like this year, it may have to dodge a nuclear bomb.
How great to have an integrated summary!  Thank you.  I learned a lot from it -- I'll be revisiting and learning more.
Given how important SSTs are, do you think the situation of relatively cooler waters in the Atlantic is likely to persist this melting season?  Are warmer waters likely to eventually punch through to the Barentz and beyond?

29
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 06:57:47 AM »
No, the GAC did not compact the ice it MELTED it. The reason the dispersion curve dropped after the GAC is that dispersed ice was more prone to melting than ice piled up on the CAA.

The GAC was not a magic cyclone that violated the Coriolis effect, compacting dispersed ice.

Okay, then, that does seem a sounder explanation ... but it was a beautiful grenade.  And Gerontocrat's extent over area graph could be useful now, considering that 2019 is in 2nd place for the date... thus indicating high dispersion of ice and therefore higher vulnerablilty to melting.  It will be interesting to see how this ratio develops over the next few weeks. 

30
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 06:43:36 AM »
A quick and dirty insolation calculation could made by making a grayscale version of Worldview's truecolor image for the date, ...

It would definitely be quick and dirty.  Gerontocrat was not kidding when he talked about the cost of developing a model that would accurately account for the cloud effects on albedo. 

Clouds are very, very, very complicated.  They are all different.  Different clouds let in different wavelengths of light that have different energy.  Different clouds also block upwelling wavelengths of light and reflect them back to the surface.

There are many papers on this topic.  The take home message is that it is not a simple matter of saying it’s cloudy so the Ice is protected.  Sometimes the clouds make things worse.

Sure, clouds are complicated, hence the desire to not have to handle them

My suggestion is for a method to calculate raw insolation, not longwave and other processes. Quick and dirty, but also simple. My thought is that the whiter clouds are, the more sunlight they reflect,
Agreed, as per my #2837 reply.   The data sets of insolation might tell a very interesting story over an entire season, and be useful for comparisons between different melting seasons.

31
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 07:03:56 PM »
Meanwhile, how about a grenade?

DIspersion vs Concentration

Convention has it that the GAC smashed up the ice and sent it all over the place. Did it?

By end July 2012 Arctic Sea Ice was well on its way to a record low. Area was decreasing even faster than extent and thus the dispersion ratio increased strongly to record levels in early August not seen before or since. Thin fragmented dispersed ice everywhere.

Then from August 2nd to August 14 was the GAC.  From August 9th to end August dispersion crashed from nearly 170% to the 2010's average of 155%. This means area loss was below extent loss. The GAC did not disperse the ice, it shoved it together. Concentration (compaction) increased.
______________________________________________________________________
Contrast this with 2016. Dispersion increased to above 2012 levels until the sea ice minimum.
What will 2019 do? On this melting season thread most say - melt.
___________________________________________

That was a beautiful grenade.  And it might make sense... early dispersion produces lower ice concentrations in August, allowing for more extreme compaction by the GAC in the fall.  Just thinking aloud and admiring your ingenuity... 

32
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 06:30:56 PM »
Since I am still learning (old hands can roll their eyes and pass on to the next message) I only just found out what a fantastic tool the Corrective Reflectance Bands 7-2-1 Aqua-Modis filter is on Worldview.  The thicker clouds sure do POP UP.  'Normal' Worldview image for comparison below.

Third image is of the 7-2-1 image tweaked via Curves on Photoshp. 

PS   Still dreaming of a tool/data base that measures and maps when and where the sun has virtually unimpeded access to the ice and open water, even if it is a rough-and-ready one.  I think it would be useful and it seems possible... 

33
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 05:41:20 PM »
Amazing~
all gone!
click to animate~

Pretty amazing to compare the last frame with the EASE sea ice age
And, as others have noted, that more of that multi-year CAB ice is about to be express-mailed through the Fram Strait...

34
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 05:02:01 PM »

My last speculation is - all other things being equal - that minimum will be later than average this year (October 1 - only half-joking).


Daring!  The decadal trend 1979-2010 (Charctix interactive extent below) was towards a later minimum, but that reversed somewhat in the last decade (2011-2018).   This was counterintuitive to me.  But maybe if ice melts so far back that there is open ocean close to the pole, then that far north open ocean refreezes quickly as winter approaches??

35
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 04:48:41 PM »
Can't you just say humanity? I am offended by women exclusion, they're as bad as men.
No, maybe that should be hupersonity to be nonsexist.
No, wait, huperdaughterity?

Can we stop here?  I know it's "just joking around", but intentionally or not, this interchange is acquiring a tone that is mocking of the efforts of women (and men) to produce a world with more equality.  It also communicates a sense that this is forum where men dominate and women must accept their 'second place'.  We should avoid this.  Can we get back to the science? 

36
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 04:00:38 PM »

Anyone who doubts whether the Barents and Greenland Seas are up to the task of melting any ice flowing in from the CAB should look at this animation.

I for one do not doubt the ice in the Barentz and Greenland Seas will melt out.  It almost certainly will.  The question from my point of view is how far the ice on the Atlantic side will melt back within the CAB, given how far the ice is still out in the Barentz this year.   (I would lean to it melting back as far as the Barentz shelf, but again, I am not sure.)

37
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 08:19:03 PM »
Quote
Eyeballing the overall Arctic basin, and using the patented Pagophilus Cloud Meter (me) I would say that cloud cover has been very low over the past week.  So, lots of lovely summer solstice sunshine for the ice, 24 hours a day.

BTW, although I agree that cloud detection on an icy background is not an easy thing to do
Albedo over ice is small (low?) and putting clouds over it will reduce it some.  Clouds over open water, however, would be 'significant'.
Agreed!   Ocean albedo is very low, about 0.06 (maybe effectively higher in the Arctic because of the low angle of insolation, but not much.  Sea ice albedo varies from 0.5 to 0.7 so MUCH higher reflectance (50-70% incoming radiation).   However, it does therefore absorb 30-50%, and when we consider the vast area of Arctic ice that is a huge amount of energy on a daily basis.  I would argue that that is significant on a seasonal basis, if the ice pack remains under clear skies for a long period of time.  However, I don't have the experience to know how much this factors in compared to the other melting stressors the ice comes under at this time.   :)

38
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 06:59:23 PM »
How is that insolation anomaly created.

Are we using something to determine if there was clear skies or not
Tealight did it. Over simplified explanation below.
Uses the area data and applies the standard insolation parameters to each bit of data with albedo dependent on open water or ice.

It is Albedo Warming POTENTIAL. -  does not take into account cloudiness. So actuality by definition must be less. There must be clouds somewhere. If you have a few billion bucks lying around doing nothing I guess somwhere somone might sort the cloudiness thing out. But looks damn complicated given the varying natire of clouds.

But it is telling us that the direction of travel this year is DOWN even given average weather.

Eyeballing the overall Arctic basin, and using the patented Pagophilus Cloud Meter (me) I would say that cloud cover has been very low over the past week.  So, lots of lovely summer solstice sunshine for the ice, 24 hours a day.

BTW, although I agree that cloud detection on an icy background is not an easy thing to do, I think some sort of instrument might be readily adapted or built.  It might even use already-existing Worldview imagery.  At this point in the year, many clouds are brighter than the rapidly bluing/graying ice.  Even if the results were not fully definitive with respect to cloud cover, the data might provide a useful year on year basis of comparison.

(Pagophilus now leaps nimbly to the back of the group of posters lest he be volunteered for this task).   

39
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 06:48:00 PM »
Ummm... I have a question about the discussion of when we should pay attention to data or prediction. Shouldn't we pay prime attention to the present when considering new record bad conditions?

It seems to me that predictions are nice to have, but it's not like they're actual data, and it's also not like we could avert anything by knowing the prediction a few days in advance. And predictions that fail to manifest seem to harm credibility.

AmbiValent, you have a strong point about in your urging us to pay attention to actual data, in my view, and that is what the area and extent thread is all about, and the PIOMAS update thread to a lesser degree.  I have argued the point myself.  I think that most posters on this thread also pay close attention to data, but ... it is also interesting and instructive and just plain fun to look ahead.  Scientists don't just analyze data retroactively, they test their understanding by making predictions and seeing how they work out.  You are right, however, in saying that sometimes people get carried away and I agree this can trivialize this thread. 

Weather forecasts up to three or five days into the future are often reliable, and as we see those unfurl in real time I find I learn a lot.  As magna recently reminded us, and as Sterks does on a regular (and needed) basis, forecasts more than 5 days into the future are not so reliable, and if they are seized upon as near certainties then posters are often proven incorrect and this leads to the 'well it wasn't as bad as we thought' revisionism, or just plain unembarrassed radio silence.  The same can apply when a sudden event, like the recent ice fragmentation in the ESS, lead some of us to think 'Oh boy, this is it!' and then more experienced hands remind us that in fact the ice is often more resilient than we think.  I have been guilty of this myself, and am gradually learning and gaining experience.

So, agreed on the centrality of data.  But I think it is not just fine, but scientifically healthy to make well-reasoned, thoughtfully calibrated predictions.  And if some of those don't turn out to be 'true', that is the way it is with predictions and we are still actively learning ...


40
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 06:00:05 PM »
...
With a 1,000 miles of continuous 20knot winds blow through the strait, some of that warmth is moving east and then toward the ESS after it hits the Arctic.

How does it impact the ice in the near term? I'm not sure. The Bering Strait is pretty shallow so the heat may dissipate quickly when mixing with deeper water. There's also the possibility that the remainder of the coastal ice in the ESS will blink out pretty quickly.

Something to keep an eye on.
Actually there's another branch of surface  flow from the Bering Sea that feeds the Alaskan Coastal Current and mixes with Beaufort waters...

Woods Hole Oceanus article https://www.whoi.edu/oceanus/feature/a-ticking-time-bomb-in-the-arctic/  addresses a directly related issue: the warming of the Chuckchi sea via insolation, which must have been even more extreme this year given how early ice was lost there.  This issue is described as a 'ticking time bomb' by John Toole, a scientist at Woods Hole.   

The forecast weather event you describe will be layered on top of this.   

41
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 03:20:29 PM »
Some general global context for all that we see happening now in the Arctic, from NOAA
https://www.ncdc.noaa.gov/sotc/global/201905

"This was the second warmest March–May period for the global land and ocean surfaces in the 140-year record at 0.96°C (1.73°F) above the 20th century average and 0.15°C (0.27°F) less than the record set in 2016 (+1.11°C / +2.00°F)."

"Global land and ocean surface temperatures during the March–May period were warmer than average across much of the world's land and ocean surfaces. The most notable warm temperature departures from average were present across much of the high latitudes in the Northern Hemisphere, specifically across much of Alaska, northwestern Canada, and north-central and Far East Russia. The temperature departures from average in these locations were at least +3.0°C (+5.4°F)."

The NOAA June report is of course not out yet.

42
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 01:24:25 PM »
I agree that the ice thickness in mid July determines who will survive in Sep.

Are we going to be shot if our predictions are wrong?  :o
No. Worse.

You will be trapped in the circular meta-discussion gyre with no parole.


Gerontocrat, thanks for starting my morning with a belly laugh!

43
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 04:09:05 AM »
But given the confusion the Slater map causes, I have to wonder why they publish it all.

The map actually does show probabilistic predictions, as stated on the website:

Quote
One way to think about the plot is that for the area that shows 80% probability of being ice covered on the forecast date, 20% of that area is expected to be ice free.
http://cires1.colorado.edu/~aslater/SEAICE/about.html

However, the model is purposefully simple. It is just a projection (for the same calendar date in recent years) of the average observed 50-day survival probability of ice at each concentration. It takes no account of regions, so it has reduced skill in regions that have peculiar melt patterns, where it may tend to err high (e.g. Hudson due to geography) or low (e.g. Greenland due to export). (By design, these regions tend to cancel each other out in the integrated prediction.) Just ignore such regions and the map is useful. One way to think of it as an interestingly-colored concentration map.

In fact, the predictions for the Hudson at this time of year are actually interesting. It illustrates just how greatly local conditions contribute to melt. It also gives an indication of how quickly other regions being "torched" might melt out. E.g. The Hudson will be mostly melted in 2-3 weeks, so unless conditions cool down along the Russian coast, one might likewise expect most of the yellows and oranges there to melt out in a similar period.

Finally, even if the map were not useful, "they" would not (and should not) take it down because, as it says on the website, it's not an official product, but a personal project of (the now late) Andrew Slater.

Hey petm, thank you for this.  It was enlightening to learn how you find the map useful. 

"One way to think of it as an interestingly-colored concentration map" is pretty much how I see the Slater map, and I don't think that the it is necessary if one has the NSIDC concentration map or (better IMHO) if one looks closely and critically at the Bremen AMSR2 images.  If your expertise allows you to use the Slater map on a deeper level then of course I respect that. 

And, as I wrote earlier, if the Slater prediction model works well, then it is a valuable model, period. 

44
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 02:06:58 AM »
ESS and Laptev, June 20-27

Click to animate.

The ESS was blue with meltponding before this, then it went dull gray and began to crumble.  Looks like the Laptev may be following, currently entering the dull gray stage...

45
Arctic sea ice / Re: Arctic Image of the Day
« on: June 28, 2019, 01:18:44 AM »
Melting snowman agrees! Uncanny...
Excellent!  And I will try to raise you with...

"Alpine peaks and a glacier on a snowy evening"

by Worldview C.A.A.  July 27, 2019.

46
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 12:57:10 AM »

there won't be ice in hudson by then.

what would that take away from the 2nd place prediction ?

The Slater prediction has its value, but the Slater map, in my view, is pretty strange.  I would not base any specific interpretations upon it.

I covered this in Reply 1487 in significantly more detail but the Slater map is a map of the current conditions and does not depict the extent predicted.

Thanks for the clarification.  I know a lot of people respect the Slater prediction, so I will certainly respect that.  But given the confusion the Slater map causes, I have to wonder why they publish it all.  It is, as you state in Reply 1487 really just a differently colored version of the current NSIDC concentration map (they should state that this is the case, BTW).  The map only puzzles people who see it (Magna this year, myself last year), at least in this context.  And it made me mistrust what by all accounts is a pretty good predictive tool.   

47
The forum / Re: Forum Decorum
« on: June 27, 2019, 10:36:46 PM »
I haven't noticed, but I'm not following all the threads (which would be nigh impossible). If it gets out of hand, please, let me know.

Hi Neven,

First, thanks for the forum (I really like and value it) and all you do.  The melting thread is way better than last year in my view, when multiple posters were overly aggressive, underinformed, unwilling to learn and ludicrously hyperbolic.   

But issues still arise, and I have to agree with sidd.  I see posters such as Klondike Kat and Michael Hauber in particular advancing reasonable, well-supported arguments that go just a little against the grain of catastrophist arguments, and they are then sneered at for being denier trolls. 

The degree of seeming bitterness and verbal aggression towards people who may have a different and often more nuanced view of the melting of the ice is surprising to me.  It is also counter-productive on a scientific level.  I view those who reasonably challenge the ideas of others as essential to any serious intellectual discussion.   

48
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 10:14:19 PM »
The more I learn on this forum, the less I know, and I am less willing to predict anything. :)

+1 and then some...

49
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 27, 2019, 09:51:51 PM »
Average area loss over the last half of June is over 100k per day. That would get us to zero in September if we kept that pace. I'm guessing we'll slow down.

It's an impressive loss of area, but apparently not unusual for late June, since the slope on the area graph looks comparable to other years at this point.  We'll see what happens...

50
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 09:35:08 PM »
Slater model projected extent for Aug 16th: 5,12 m sq km (a solid second place)

nsidc extents on the same date :

2012: 4,77
2007: 5,39
2016:5,47
2017:5,42
2018:5,64

there won't be ice in hudson by then.

what would that take away from the 2nd place prediction ?

The Slater prediction has its value, but the Slater map, in my view, is pretty strange.  I would not base any specific interpretations upon it.

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