Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Neven on July 08, 2019, 10:49:30 PM

Title: 2019 vs 2012
Post by: Neven on July 08, 2019, 10:49:30 PM
We're entering what will be a highly educative event. I've just ended the latest PIOMAS update (https://neven1.typepad.com/blog/2019/07/piomas-july-2019.html) on the ASIB with this:

Quote
The only question on my mind right now, is: Can 2019 beat 2012? No, wait, I know it can. Allow me to rephrase. The only question on my mind right now, is: Will 2019 beat 2012?

2012 and 2019 are very similar in their respective horrible states, but there are differences. This thread is about those differences. For more general talk about 2019 conditions and weather forecasts, use the 2019 melting season (https://forum.arctic-sea-ice.net/index.php/topic,2591.msg211935.html#msg211935) thread. For off-topic banter, theories and discussions about wider implications use the meaningless chatter (https://forum.arctic-sea-ice.net/index.php/topic,2274.msg211928.html#msg211928) thread (please, use it).

This thread is about 2012 vs 2019, and what I would like to see most of all, are graphs, maps and satellite images that highlight the differences. And so I'll kick off with the following:

1) PIOMAS June sea ice volume
2) PIJAMAS average sea ice thickness
3) NSIDC compactness
4) JAXA melt extent ratio
Title: Re: 2019 vs 2012
Post by: pearscot on July 08, 2019, 11:06:05 PM
I decided to go back and check out the sea surface anomalies since Alaska has seen record breaking heat this year and to be honest I'm amazed at 2012 - I thought this year was warm, but looking at these two years side by is certainly enlightening (to me at least).


Title: Re: 2019 vs 2012
Post by: Neven on July 08, 2019, 11:06:32 PM
SAT anomalies July 1-6:
Title: Re: 2019 vs 2012
Post by: Neven on July 08, 2019, 11:13:39 PM
I decided to go back and check out the sea surface anomalies since Alaska has seen record breaking heat this year and to be honest I'm amazed at 2012 - I thought this year was warm, but looking at these two years side by is certainly enlightening (to me at least).

This offers a better perspective from the top of the world, instead of Mercator projection:
Title: Re: 2019 vs 2012
Post by: Rich on July 09, 2019, 01:14:40 AM
Atmospheric CO2 levels are currently ~ 15 ppm higher than 2012.

This is most relevant toward the latter portion of melting season when heat escape becomes a bigger factor.
Title: Re: 2019 vs 2012
Post by: Tunnelforce9 on July 09, 2019, 01:19:37 AM
Greenland's melt is cooling the ocean maybe that explains the huge difference in sst anomaly

http://climato.be/cms/index.php?climato=the-2019-melt-season-over-greenland-as-simulated-by-marv3-9
Title: Re: 2019 vs 2012
Post by: prokaryotes on July 09, 2019, 01:19:50 AM
Atmospheric CO2 levels are currently ~ 15 ppm higher than 2012.

This is most relevant toward the latter portion of melting season when heat escape becomes a bigger factor.
What about the winds up there, is it very stormy?
Title: Re: 2019 vs 2012
Post by: petm on July 09, 2019, 02:34:46 AM
In addition to a strong setup (thin ice and heat accumulation, which both 2012 had and 2019 has), I think cyclones are needed. 2012 had several significant ones in July and then of course the big one in early August. A few days after each of them, the damage was obvious. So far, 2019 has had only a few, mostly in the Beaufort (which is suffering accordingly). But the waters are warm and the air humid, so it seems likely we should see some soon. Waiting...
Title: Re: 2019 vs 2012
Post by: Rod on July 09, 2019, 03:44:24 AM
July 8 is very clear in Worldview for both 2012 and 2019 on the pacific side.  These are the comparisons that continue to strike me as the most important currently if we are talking about “extent” as our endpoint.

If the Beaufort becomes a killing zone as most believe it will, it looks like 2019 will definitely beat 2012 on this side of the arctic.

The current situation around Wrangel Island is incredible.



Title: Re: 2019 vs 2012
Post by: Juan C. García on July 09, 2019, 06:08:23 AM
By looking at ADS (JAXA) 2011 and 2012 trajectories, I think that 2019 will compete with 2011 to be the lowest on record until July 23rd, but 2012 will be the 3rd or 4th lowest until the 23rd.
Title: Re: 2019 vs 2012
Post by: ArcticMelt2 on July 09, 2019, 06:20:55 AM
https://twitter.com/kevpluck

(https://pbs.twimg.com/media/D-zSuT3XsAUktpr.png)
Title: Re: 2019 vs 2012
Post by: Rod on July 09, 2019, 06:49:46 AM
AM2.  That is Kevin Pluck’s map.  We have already discussed it in the melting season thread and established it has errors.

I contacted him on Twitter, and he posted on the forum a few days ago and explained his data set. 

He used a dataset that can not be reliably used for climatological purposes.  That is why the Hudson area is wrong.

There are several posts discussing this in the melting season thread.

To be clear, I think Kevin Puck is a really smart guy who makes great images!  However, this one is just not completely accurate.
Title: Re: 2019 vs 2012
Post by: ArcticMelt2 on July 09, 2019, 06:53:18 AM
AM2.  That is Kevin Pluck’s map.  We have already discussed it in the melting season thread and established it has errors.

I contacted him on Twitter, and he posted on the forum a few days ago and explained his data set. 

He used a dataset that can not be reliably used for climatological purposes.  That is why the Hudson area is wrong.

There are several posts discussing this in the melting season thread.

How big are these mistakes? A simple comparison of images shows that the map is generally correct.
Title: Re: 2019 vs 2012
Post by: Rod on July 09, 2019, 06:54:47 AM
The main errors were in the Hudson.  I think everything else is pretty much correct.
Title: Re: 2019 vs 2012
Post by: ArcticMelt2 on July 09, 2019, 06:59:58 AM
The main errors were in the Hudson.

I agree. In 2012, there was no ice there.

https://sites.google.com/site/arcticseaicegraphs/concentration-maps/sic0707

So it’s still worse than it seemed to me before.
Title: Re: 2019 vs 2012
Post by: Rod on July 09, 2019, 07:07:11 AM
You also need to give people credit when you copy their work off of Twitter.  You keep copying Rick Thoman’s graphs without properly giving him credit.   He watches these forums.  You need to provide his name when you post his work so that people know where it came from.
Title: Re: 2019 vs 2012
Post by: ArcticMelt2 on July 09, 2019, 07:12:14 AM
You also need to give people credit when you copy their work off of Twitter.  You keep copying Rick Thoman’s graphs without properly giving him credit.   He watches these forums.  You need to provide his name when you post his work so that people know where it came from.

The authorship of the image indicated on her. But I added a link to his twitter.
Title: Re: 2019 vs 2012
Post by: oren on July 09, 2019, 08:00:34 AM
Making a probable summation, Beaufort + ESS + CAA should be around 250 km3 by the minimum (compared to 50km3 for 2012), and Greenland Sea another 250 km3. Adding the CAB should get the total to less than 4400 km3, with the lower limit not well defined.

Overall, I expect 2019 to pass 2016 (4400 km3) and 2011 (4300 km3) and reach 2nd place in volume. I'd be quite surprised if it manages to break 2012's 3670 km3 record.

I've posted regional charts and the above heuristic conclusion on the PIOMAS thread.
Title: Re: 2019 vs 2012
Post by: BenB on July 09, 2019, 08:54:56 AM
To add a bit of context to the Piomas comparisons from 30 June, here is a comparison of the ice edge at 30 June and 7 July (latest available) this year. Apart from the retreat in the Chukchi, what is striking is how much has been lost from the areas where the big positive anomalies were in the Barents and edge of the Kara:
Title: Re: 2019 vs 2012
Post by: BenB on July 09, 2019, 09:43:18 AM
And another comparison. This time the latest data from this year is compared with 3 weeks forward in time in 2012 (July 7 vs July 28). It looks like there's a lot of ice that needs to melt, but I think 2019 will be ahead on the 28th, at least in the areas that matter to the final extent. This year, a huge swathe of ice south of 75N between the New Siberian Islands and the eastern edge of Chukchi is vulnerable. Not all of it will melt out, but a lot will. Sea by sea:

Kara/Barents: 2019 is far behind, but these areas are melting rapidly. 2012 will stay ahead at 28 July, but not by very much.
Laptev: The areas by the Lena delta and between the Laptev bite and Severnaya Zemlya will again melt out completely. The Laptev bite will extend further into the CAB. 2019 a bit ahead, if you include the Laptev sector of the CAB.
ESS: The area south-east of the New Siberian Islands will melt out fully, as will most of the eastward extension of the Laptev bite. In addition, there will be significant melt along the Siberian coast. 2019 well ahead.
Chukchi: 2019 is already ahead and will extend its lead. 2019 far ahead.
Beaufort: there's some thicker ice here, so I think the two years will be similar.
CAA: 2012 had earlier momentum, so I think it will be significantly ahead.
Baffin: not really relevant to the final extent, but I think 2019 will also melt out fully by 28 July. Equal.
Hudson: again not relevant, but 2019 may not melt out fully by 28 July. 2012 possibly a bit ahead.

Even if I'm right and 2019 is ahead on 28 July, 2012 has the GAC to come, so for me the final outcome is still very uncertain. 2019 could end up significantly ahead or behind 2012. The latest forecasts suggest cooler weather is coming...
Title: Re: 2019 vs 2012
Post by: gmrocher on July 09, 2019, 11:05:10 AM
Hi,
I am a weekly follower of this blog for the past years, but never got to comment anything. The work here is too good! I just finished my PhD in stream biogeochemistry and CO2 evasion in arctic rivers, so this is a bit tangential for me but I am familiar with the scientific method of course.

I have been following the the ice front in the CCA and Greenland, and something that is evolving worryingly fast is a large crack that seems to appear now already over greenland. This part is much more developed than 2012 by the same dates.

(I attached an image, not sure is visible in the post yet)
Title: Re: 2019 vs 2012
Post by: Neven on July 09, 2019, 12:56:34 PM
Thanks for all those comparisons, especially the satellite images. That comparison of the Pacific side is just... wow.

Not very relevant, but still, here's a comparison of the DMI 80N SAT graphs:
Title: Re: 2019 vs 2012
Post by: oren on July 09, 2019, 01:00:46 PM
Welcome, gmrocher.
This crack is more the effect of winds and ice mobility than of melting. But it's still worrisome nevertheless.
Title: Re: 2019 vs 2012
Post by: b_lumenkraft on July 09, 2019, 01:10:56 PM
Welcome, gmrocher.
This crack is more the effect of winds and ice mobility than of melting. But it's still worrisome nevertheless.

But isn't the increased ice mobility due to thinner ice and therefore due to melting? Melting that occurred in recent seasons rather than this season i mean.

And to you Gmrocher, hello and welcome to the forum! :)
Title: Re: 2019 vs 2012
Post by: oren on July 09, 2019, 01:21:17 PM
You are correct. I mean it's not in situ melting near the coast of the CAA and Greenland that has finished off the 3m thick floes found there, but rather melting elsewhere that has enables this ice to move away.
Title: Re: 2019 vs 2012
Post by: Paddy on July 09, 2019, 01:25:46 PM
I'd put the chances of this year ending up lower than 2012 at a fair bit less than 50%, given that the loss from this point on in 2012 (5.08million sq km) was the highest loss over that period in the past ten years and quite a bit more than the average of 4.11m sq km. There's a definite possibility, but so much depends on the weather, and 2012's July/August melting conditions were pretty exceptional.
Title: Re: 2019 vs 2012
Post by: b_lumenkraft on July 09, 2019, 01:29:09 PM
Right, Oren! :) 🖖🏽
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 09, 2019, 09:55:06 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F20st6k9.gif&hash=87d47961d3ded10adc7ad649e5b7c0fa)
From NSIDC archive of daily Arctic sea ice concentration images

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2012/07_Jul/N_20120708_conc_v3.0.png
vs.
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019/07_Jul/N_20190708_conc_v3.0.png

FWIW - Some amateur opinions for consideration and feedback:
1) to my eye July 8 2019 ASI concentration looks more vulnerable than same date 2012.  The few areas where 2019 has more ice are doomed by Sept. anyway.

2) I don't think the extent and area metrics we use to compare between years fully reflect the degraded ice condition in 2019.  Volume has a better chance of reflecting actual situation, but of course it has its own issues.

3) There is still a lot of melt season weather left to go, and as reported in the forum, late July-August 2012 weather was conducive to melt.  While June 2019 was blistering, it remains to be seen what remainder of 2019 melt weather will be like, but it will be hard for 2019 to match late-season 2012.  So that's gives an edge to 2012 in terms of the Sept. minimum extent/area/volume.

4)  And 2012 had the Great Arctic Cyclone. I have to assume that an event of that impact is unlikely in 2019.  But 2019 may bring its own events -- perhaps a couple of less intense events will have cumulatively equal impact as the 2012 GAC.  A return of an Arctic dipole hinted at in the 10-12 day forecast yesterday is an example of hits 2019 could yet deliver to the weakened ice fortress.
   
 5) Of greatest importance -- 2019 includes 7 additional years of a) continued decline of anchoring multi-year sea ice, b) what appears to be qualitative functional changes in ocean heat incursion, c) increased ice pack mobility, d) polar vortex weakening, e) higher atmospheric CO2e, and f) higher global SAT -- by about 0.3C increase between 2012 to 2019.  That's a huge amount of extra energy in the surface layer of the climate system (not even counting the energy buried in the ocean, some of which could affect Arctic sea ice melting this year).  There is a lot of additional heat embedded in the Arctic and surrounding system in 2019 vs. 2012.
   
   6)  Because of #5, I think we really can't know how close to the cliff we are.  But we can be sure that we are getting closer to that cliff every subsequent year of not only persistent elevated GHG level, and not just year-on-year additions, but increases in the rate of increase of GHG loading. 
 
   7) So... 2019 vs. 2012?  A toss up for Sept minimum only because 2012 was such a blow out.  But on the current trajectory it's just a question of when, not if, cumulative progression will push the system below 2012 and make every year below 2012. 

  8) It's natural to focus on  landmarks like Sept. minimum extent/area/volume, but in case you missed it, see the 365-day running average extent the industrious and appreciated gerontocrat posted at https://forum.arctic-sea-ice.net/index.php/topic,2533.msg211770.html#msg211770 (https://forum.arctic-sea-ice.net/index.php/topic,2533.msg211770.html#msg211770).  And the even more dramatic 365-day running average volume posted at https://forum.arctic-sea-ice.net/index.php/topic,119.msg211798.html#msg211798 (https://forum.arctic-sea-ice.net/index.php/topic,119.msg211798.html#msg211798).
     More than the ASI status on a single September day, those trends show the larger story of what we are doing to a critical part of our climate system. 

     The world needs the people informed by this forum to spread the news of this existential threat to family, friends, neighbors, colleagues, and politicians.  Please talk about it, that is the essential first step.       

Title: Re: 2019 vs 2012
Post by: Neven on July 10, 2019, 12:07:46 AM
For those interested in anecdotal evidence of what happened in 2012 around this time, I can highly recommend my own writings (someone has to do it) on the ASIB at the time: ASI 2012 Update 6: piggy bank (https://neven1.typepad.com/blog/2012/07/asi-2012-update-6-piggy-bank.html)
Title: Re: 2019 vs 2012
Post by: magnamentis on July 10, 2019, 12:09:49 AM
....The world needs the people informed by this forum to spread the news of this existential threat to family, friends, neighbors, colleagues, and politicians.  Please talk about it, that is the essential first step.     

a superb resume, thanks.

from time to time some of the main ingredients to the soup have to be resumed the way you just did to bring structure into the discussion that is often driven by tiny standalone day to day events.

that's worth one of my sparse likes LOL
Title: Re: 2019 vs 2012
Post by: Neven on July 10, 2019, 11:06:17 PM
In anticipation of tomorrow's data, 2019 is leading 2012 by 157K for JAXA SIE, and 2012 had a 133K drop reported for the 10th. 2012 had another century break reported the day after, but this was followed by four slower days (two of which were 49 and 47K), so if 2019 can keep up the pace for a while longer, it may build up something of a buffer. FWIW.

Below is the build-up so far this month:
Title: Re: 2019 vs 2012
Post by: Bruce Steele on July 10, 2019, 11:43:43 PM
gmrocher, Welcome to the forum . Maybe you could help us on the" Carbon Cycle "page on occasion ?
I try to educate myself on biogeochemistry but without the sounding board that academia provides it is hard to know when I have gone off the tracks. 
Title: Re: 2019 vs 2012
Post by: D-Penguin on July 11, 2019, 12:10:14 AM
....
     The world needs the people informed by this forum to spread the news of this existential threat to family, friends, neighbors, colleagues, and politicians.  Please talk about it, that is the essential first step.     

I really enjoy reading Glen's postings that are always so well constructed and presented.

In particular, the above concluding paragraph is so important. I wish that some multi-media outlet would 'adopt', say, the Extent, Area and Volume Thread and pay Neven a handsome 'royalty payment' for the privileged of being associated and connected to such an informative source of information.

If only scientists were also well schooled in marketing...!

If OT I apologize, will remove and look for a more appropriate thread.
Title: Re: 2019 vs 2012
Post by: Neven on July 11, 2019, 10:27:35 AM
In anticipation of tomorrow's data, 2019 is leading 2012 by 157K for JAXA SIE, and 2012 had a 133K drop reported for the 10th.

A drop of 113K was reported for the 10th, 20K less than 2012, and so the difference is now 137K. For the 11th 2012 had a 111K century break.
Title: Re: 2019 vs 2012
Post by: gmrocher on July 11, 2019, 10:31:19 AM
gmrocher, Welcome to the forum . Maybe you could help us on the" Carbon Cycle "page on occasion ?
I try to educate myself on biogeochemistry but without the sounding board that academia provides it is hard to know when I have gone off the tracks.

Yes of course! I'm no expert but it is my topic yes. I wasn't aware of these other pages of the forum, so much info here
Title: Re: 2019 vs 2012
Post by: pleun on July 11, 2019, 10:50:46 AM

     The world needs the people informed by this forum to spread the news of this existential threat to family, friends, neighbors, colleagues, and politicians.  Please talk about it, that is the essential first step.   
 

absotively true, but everytime I bring this up, I see eyes rolling up. People just don't want to hear about catastrophe unless it's on their doorstep...
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 11, 2019, 08:51:18 PM
absotively true, but everytime I bring this up, I see eyes rolling up. People just don't want to hear about catastrophe unless it's on their doorstep...

Agreed, but it still needs to be said.  And I bet your bringing it up makes a difference to those people (like kids who don't seem like they listen  then 10 years later they remind of something you said that shows they really were hearing you all along).  https://thinkprogress.org/the-most-important-thing-you-can-do-right-now-to-fight-climate-change-according-to-science/ (https://thinkprogress.org/the-most-important-thing-you-can-do-right-now-to-fight-climate-change-according-to-science/)

The AIDS campaigners pegged it - Silence is death.  Politicians have told me they'd do more on climate crisis but they just don't hear about it from constituents.  I think the tide is changing on that in U.S.   With 2020 election ramping up, climate is getting some respect for the first time.  Still only 14 minutes in first 4 hours of Dem candidate debates.  But that 14 minutes is more than TOTAL discussion of climate during all of the 2016 debates. 

Social change studies show that things don't change, and don't change, and don't change, until... seemingly in a flash, for no obvious reason, they do change very quickly.  But that slow incremental process from 1 to 2 to 3% etc. was what made it possible.  Gay marriage in the U.S. is a striking example.

Studies also show that only 10% of population needs to adopt an idea before it catches like wildfire.   While much more than 10% are already aware and concerned about climate, we need to get over the 10% hump of population ready to take on the large scale systemic change needed -- that WWII type mobilization often cited as the model for what needs to happen.  So yes, 95% may act like they aren't listening, but having it in conversation over and over is the way we get to that 10% threshold IMHO.  We gotta try. 
Title: Re: 2019 vs 2012
Post by: Oscillidous on July 11, 2019, 10:57:53 PM
Studies also show that only 10% of population needs to adopt an idea before it catches like wildfire.   While much more than 10% are already aware and concerned about climate, we need to get over the 10% hump of population ready to and take on the large scale systemic change needed ... 95% may act like they aren't listening, but having it in conversation over and over is the way we get to that 10% threshold IMHO.  We gotta try. 

Agreed. I would argue that the biggest issue is that while many know about climate change, they aren't familiar with the rate of change that is occurring. They are under the impression that in 2050 it will be messy, some even believe we don't have to worry until 2100.

My uneducated analysis of this year vs 2012 is that while the amount of ice loss is pretty similar, the overall quality of ice was much better and more resilient to bad conditions in 2012. This year, it looks like the entire pack is slushy and mobile (obviously some pieces being larger than others).

I have a hard time envisioning this season resulting in any substantial rebound of the ice, another big difference from 2012. I think next year's melt season will start earlier and I imagine refreeze will start later this year. The biggest difference with this year vs 2012 is we lost similar amounts of ice without a GAC. Keep in mind though, this is coming from someone who still can't identify a dipole on a geopot chart :x
Title: Re: 2019 vs 2012
Post by: Stephan on July 11, 2019, 10:59:00 PM
[...]
     The world needs the people informed by this forum to spread the news of this existential threat to family, friends, neighbors, colleagues, and politicians.  Please talk about it, that is the essential first step.     
I use a whiteboard in the hallway in my office building and the first thing I do every morning before I open my office I write down the actual JAXA arctic + antartic extent difference compared to the 2000s average, together with a short list of #1, #2, #3 and #40 and #41 years with the biggest difference to that average. Most of the colleagues look at the numbers, and climate change is one of the main topics in of the discussions during coffee breaks [I have to confess there are some deniers among them].
Title: Re: 2019 vs 2012
Post by: Neven on July 12, 2019, 10:08:44 AM
A drop of 113K was reported for the 10th, 20K less than 2012, and so the difference is now 137K. For the 11th 2012 had a 111K century break.

A drop of 'only' 67K was reported for the 11th, 44K less than 2012, and so the difference is now 93K. For the 12th, 2012 had a 93K drop.
Title: Re: 2019 vs 2012
Post by: Neven on July 13, 2019, 10:35:44 PM
A drop of 'only' 54K was reported for the 12th, 39K less than 2012, and so the difference is now 54K. For the 13th, 2012 had a 49K drop.

And here's SAT and SLP this month so far:

Title: Re: 2019 vs 2012
Post by: Neven on July 13, 2019, 10:39:01 PM
On the NSIDC front, 2019 is still leading 2012 by 46K for extent and 2012 is leading by 9K for area.

2012 is 0.5% lower than 2019 for compactness:
Title: Re: 2019 vs 2012
Post by: JayW on July 13, 2019, 10:49:57 PM
Pacific side comparison, July 12.
Chick to run
Title: Re: 2019 vs 2012
Post by: Comradez on July 14, 2019, 09:44:22 PM
I did an in-depth video analysis of 2012 vs. 2019 with regards to a portion of the Central Arctic Basin around 80N and 150W that borders on the Beaufort and Chukchi.
https://youtu.be/Dda9agEL7Is

I think 2019 actually looks worse than 2012 in this important region.  Even without a Great Arctic Cyclone, 2019 may challenge 2012 everywhere outside of the CAA, where 2012 will probably have an edge.
Title: Re: 2019 vs 2012
Post by: Neven on July 14, 2019, 10:38:41 PM
Very nice, Comradez! This is exactly the kind of stuff I was hoping to see when opening this thread. I've written a quick blog post on the ASIB, linking to your video, called Comparing (https://neven1.typepad.com/blog/2019/07/comparing.html).
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 15, 2019, 06:46:19 PM
(https://i.ibb.co/3vpq1SP/Arctic-sea-ice-concentration-NSIDC-July-14-2012-vs-2019.png)
Title: Re: 2019 vs 2012
Post by: gerontocrat on July 15, 2019, 07:00:16 PM
If 2019 remaining area loss is average, NSIDC minimum area will come in at or a bit less than 200,000 more than 2012.

2019 extent minimum, given average remaining loss, will be at at least 800,000 km2  more than 2012.

The reason for this difference is that in 2012 the ice was more concentrated. You see the same in 2016. So maybe the main difference between 2012 and today is the ice is so much more dispersed. Extent as a measure becomes increasingly misleading as dispersion increases?



Title: Re: 2019 vs 2012
Post by: jai mitchell on July 15, 2019, 10:05:03 PM
We will know if 2019 will approach 2012 levels in about 3 weeks.  I doubt it as the unusual rapid decline in surface ice cover around the first week of August has not been repeated since. 

Until the early august rate of cover loss decrease is broken, we won't cross 2012 for some time yet.

Title: Re: 2019 vs 2012
Post by: Killian on July 16, 2019, 04:53:18 AM
Per a response to someone somewhere on these fora re short periods of melt having a large impact on ice minimums, anyone have a clear idea why there was such massive loss of ice from Aug 2nd to Aug 9, 2012?

Extent was 6.03M km sq on the 2nd and fell to 5.04M km sq by the 9th for a loss of 990k km sq in 7 days, averaging 141.4k km sq/day. The weeks before and after that drop were decidedly normal:

7/26 ~ 8/2 = 6.51 - 6.03 = 480 / 7 = 68.57k km sq/day
8/9 ~ 8/16: 5.04 - 4.47 = 570 / 7 = 81.4k km sq/day.

These two weeks averaged 75k km sq  or 525k km sq on average vs 990k km sq, almost double.

2012 had another big loss earlier in the season from 6/06~6/13 falling from 11.17M km sq to 10.22M km sq, or 950k km sq, an average of 135k km sq/day. The average of these two weeks is 970k km sq or 445k km sq more per week than more typical weeks for excess loss of 990k km sq.

2016 had remarkably consistent trend line averaging 74km sq from 6/14 to 9/03 with no week-long periods of accelerated losses.  Even the early season was fairly similar to the late season melt. From 4/17~6/3, 47  days, the melt was from 13.13M km sq to 10.35M km sq or 59.15k km sq/day for only a 15k km sq/day difference.

2007's pattern was completely different, though it also had no huge short-term drops. It did, however, start the season with a consistent slope averaging -109k km sq over 34 days from 6/24 (10.13M km sq) to 7/28 (6.41M km sq) before slowing over the summer.

That 990k km sq excess loss exceeds the difference between the 2012 minimum and the 2016 minimum and equals the difference between 2012 and 2007. That is, less those two extraordinary weeks, 2012 is tied for second lowest in the record, not first.

Seems to me identifying the anomalous conditions during those two weeks might provide significant insight into interpreting ASI overall, and particularly for predicting minimums given certain scenarios.

I don't have the familiarity with the data sets to suss this out, but the pattern really jumped out from the charts. Anybody want to give it a shot?
Title: Re: 2019 vs 2012
Post by: binntho on July 16, 2019, 06:17:59 AM
If 2019 remaining area loss is average, NSIDC minimum area will come in at or a bit less than 200,000 more than 2012.

2019 extent minimum, given average remaining loss, will be at at least 800,000 km2  more than 2012.

The reason for this difference is that in 2012 the ice was more concentrated. You see the same in 2016. So maybe the main difference between 2012 and today is the ice is so much more dispersed. Extent as a measure becomes increasingly misleading as dispersion increases?
I must admit that these area numbers are quite an eye opener. I've been wondering what it was about 2012 that made it loose so very much more ice than the other years, turns out that it didn't.

Extent is indeed beginning to look a bit misleading, being so sensitive to winds and weather causing dispersion or compaction, but the steady loss of area will, i guess, eventually show up in loss of extent.
Title: Re: 2019 vs 2012
Post by: UCMiami on July 16, 2019, 07:00:27 AM
Killian - three letters GAC = Great Arctic Cyclone which hit on Aug2 and devastated huge sections of ice - mostly by bringing deeper warmer waters to the surface and stirring/dispersing the ice.

To be noted also in your listing of rapid extent loss weeks - we just experienced one in July this year losing 1M km2 in a week - 9M to 8M

As posted by Philopek here in the melt season thread:
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg213000.html#msg213000
Title: Re: 2019 vs 2012
Post by: Killian on July 16, 2019, 07:44:21 AM
I've been wondering what it was about 2012 that made it loose so very much more ice than the other years, turns out that it didn't.

You'd need to include a look at area and/or volume to determine that, not extent.

As for extent, the difference between '12 and '16 comes down to two weeks, one in Spring, one in early July, with nearly 1M km sq reductions. The latter, i was just reminded, was the period of the Great Arctic Cyclone, so there was definitely some very real ice loss during that week. Perhaps not during the first one in Spring.

See above.
Title: Re: 2019 vs 2012
Post by: binntho on July 16, 2019, 07:57:01 AM
I've been wondering what it was about 2012 that made it loose so very much more ice than the other years, turns out that it didn't.

You'd need to include a look at area and/or volume to determine that, not extent.

Yes, well that was the whole point, the point I was trying to make: You need to look at area to come to that conclusion.

I've been wondering why a year like 2019 is struggling so hard to get any where near 2012 extent wise - based on the misconception that the 20% difference in extent between 1st and 2nd place was based on 2012 loosing 20% more ice than 2016, and struggling to see where such a massive difference in melt could have come from.

But when you look at area, the difference is only 8%. Still a decent number, but nowhere near as massively different compared to 2016 or indeed other years. And most of the difference extent wise is just random (if not quite Brownian) movement of existing ice.
Title: Re: 2019 vs 2012
Post by: Killian on July 16, 2019, 07:58:19 AM
Killian - three letters GAC = Great Arctic Cyclone which hit on Aug2 and devastated huge sections of ice - mostly by bringing deeper warmer waters to the surface and stirring/dispersing the ice.

Ah. Right. I should have made that connection. Well, then, the debate about whether it mattered much to 2012 and/or will matter in this or future years is pretty much settled. As I noted above, remove that and the other springtime big loss week, and the difference between '16 and '12 disappears.

But what dropped the extent @ 1M km sq in the spring for the other half of the difference?

Quote
To be noted also in your listing of rapid extent loss weeks - we just experienced one in July this year losing 1M km2 in a week - 9M to 8M

Yes. Well aware. It was pretty warm, and until recently export via Fram and and Nares has been high. Westerlies and the dipoles have always been discussed as the primary causes of the great loss in 2012, but now I'm not so sure - unless those were the causes of the spring 2012 big melt week. I think they explain '12 being otherwise equal to '07 and 2nd to '16 - note the upside-down, flattened Bell Curve shape showing larger than normal losses at the end of the melt season - but the real losses that drove '12 almost 1M km sq lower than 2016 would be came long before Sept.
Title: Re: 2019 vs 2012
Post by: grixm on July 16, 2019, 08:35:43 AM
DMI's thickness model shows pretty different results to PIOMAS. Where PIOMAS has 2012 and 2019 pretty much tied for volume at this point, 2019 is lagging pretty far behind according to DMI: (click to play)

I asked what the difference between these models are in the PIMOAS thread and why no one seems to talk about DMI, didn't get a response.
Title: Re: 2019 vs 2012
Post by: oren on July 16, 2019, 09:00:15 AM
A. 2016 also had a GAC of sorts, that contributed a lot to late season area loss. The GAC was later than 2012's.
B. 2016 nearly tied 2012 for area in the CAB, per the UH AMSR2 measure. The difference with 2012 was in other regions (CAA, ESS and maybe others) that didn't clear out in 2016. The CAB "tie" came late and went away fast.
C. 2016 had a very early min date, while 2012 managed to linger to a late min date. On Sep 8th the 2012-2016 difference was much smaller.
D. The early min in 2016 came about partly because of lots of open water and low concentration ice in the region near the pole.
Title: Re: 2019 vs 2012
Post by: binntho on July 16, 2019, 09:02:51 AM
I asked what the difference between these models are in the PIMOAS thread and why no one seems to talk about DMI, didn't get a response.

I think it's one of those things where only a few people really know the answer, and they've answered it already several times through the years.

But I seem to remember the DMI model being considerered somewhat dubious compared to PIOMAS and CryoSAT. And there is actually a whole discussion about those two, PIOMAS vs CrySat (https://forum.arctic-sea-ice.net/index.php/topic,8.0.html)
Title: Re: 2019 vs 2012
Post by: Yuha on July 16, 2019, 09:17:07 AM
2012 was not unusually compact in September but pretty close to other years except 2016.
The abnormal year in terms of compactness is 2016, which had very exceptional dispersion in late August and early September.
Title: Re: 2019 vs 2012
Post by: Neven on July 16, 2019, 10:46:00 AM
I can now do a good comparison for July 15 2012 vs 2019, DMI SST anomalies:
Title: Re: 2019 vs 2012
Post by: DrTskoul on July 16, 2019, 12:06:49 PM
I can now do a good comparison for July 15 2012 vs 2019, DMI SST anomalies:

Same magnitude, different distribution.... Pacific is burning and there is no ice export to save the winter ....
Title: Re: 2019 vs 2012
Post by: Richard Rathbone on July 16, 2019, 12:34:45 PM
DMI's thickness model shows pretty different results to PIOMAS. Where PIOMAS has 2012 and 2019 pretty much tied for volume at this point, 2019 is lagging pretty far behind according to DMI: (click to play)

I asked what the difference between these models are in the PIMOAS thread and why no one seems to talk about DMI, didn't get a response.

DMI uses CICE (and HYCOM for the weather forecast), PIOMAS uses PIOMAS.

DMI is a model to predict extent, PIOMAS is a model to measure total volume. Either can be used for another purpose, but its rather more likely to be bad at it than its primary purpose.

DMI don't publish much on their model so my diagnosis of their weaknesses may miss something important and these weaknesses may not be the critical ones.

CICE is a model developed for GCMs which is portable into weather forecast models rather than climate models, and DMI isn't the only group that has had trouble keeping it numerically stable. (I reckon the stability issue probably arises from calculated salinity being extremely sensitive to measurement error in assimilated temperature.)  DMI publish on their model rather less than they tweak it, so its not possible to be sure just what they are doing at the moment, but last time I found something on it they were assimilating a large chunk of climatology as well as data.

DMI has an issue with melting momentum. They hit volume minimum too early and have a much too steep melting curve during the summer. I think this probably derives from their sea model being a weather forecast model rather than an ice melt model and heat that should be going into a near surface sea layer in June/July and getting back to the melt ice in August/September, is being put directly into melting ice.

If you use the same DMI model to compare 2012 and 2019, its probably not too misleading, but you need to be sure its a reanalysis of 2012 using the 2019 model, because otherwise you'll be looking at the difference between their 2012 model and their 2019 model rather than the ice. (and if its a big difference, you'll can't tell whether its real or whether the model is having one of the years in which it goes haywire)
Title: Re: 2019 vs 2012
Post by: echoughton on July 16, 2019, 12:50:28 PM
Terrific, Comradez!! As for myself, a complete non-scientist who LOVES this stuff and Neven's forum, this is what I'd like to see more of: Videos with narration showing me exactly what I want to see and learn. Keep it up...perhaps edited down a bit more
 8) 8) 8) 8) 8) 8)
Title: Re: 2019 vs 2012
Post by: oren on July 16, 2019, 12:55:02 PM
RR, thanks for the detailed response about the DMI volume. I know it's very unreliable but couldn't really explain why...
Title: Re: 2019 vs 2012
Post by: UCMiami on July 16, 2019, 05:18:09 PM
Neven - find the SST anomaly charts very interesting.
Question on this latest - How much do you think the ocean currents vary in the arctic basin both in flow and temperature year to year (not decade to decade as obviously there are world wide changes due to AGW)?

I ask because I wonder how much these anomaly temp charts reflect large melt season variations - where a arctic sea has continued import of ice or slower melt then average the water temp is going to remain depressed. For example I believe the early temp anomaly in the Beaufort was quite high, but as CAB ice export/dispersion has been very high into the beaufort, that anomaly has decreased significantly compared to 2012. Same is seen in Kara but in that case because of slower melt in that seas. But the anomalies seem to quite quickly expand in the same way as soon as ice disappears. I guess it is a chicken and egg sort of issue - does SST rise follow ice loss or does SST rise drive ice loss?
Title: Re: 2019 vs 2012
Post by: Neven on July 16, 2019, 07:59:43 PM
The things with anomalies is that when a place that would normally be covered with ice in the base period, melts out, SST anomalies will automatically jump through the roof. In that sense, for those DMI maps, SST rise follows ice loss.

Quote
How much do you think the ocean currents vary in the arctic basin both in flow and temperature year to year (not decade to decade as obviously there are world wide changes due to AGW)?

Ocean currents and the heat they transport into the Arctic, are the big known unknown. A couple of years ago, I wrote an extensive blog post on Ocean Heat Flux (https://neven1.typepad.com/blog/2012/06/ocean-heat-flux.html), and my guess is nothing has changed much since then.
Title: Re: 2019 vs 2012
Post by: Neven on July 16, 2019, 08:04:53 PM
I have a special treat for this thread, and that's the old MODIS composite (https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/latest-conditions/products-guides/satellite-images-mosaics-animations.html#modis) maps from Environment Canada. Unfortunately, the archive (https://ice-glaces.ec.gc.ca/prods/MODISCOM-F/) doesn't seem to be complete, but I referred to these maps a lot in 2012, so I managed to retrieve an old image from the ASIB that can be compared to the latest period for this year. Unfortunately it's not in high resolution.

Shapes are different and 2012 seems to have more holes towards Siberia. As said by others in the melting season thread, the ice seemed to look worse in the CAA and western Beaufort in 2012, but it's not easy to make out (click for a larger version):
Title: Re: 2019 vs 2012
Post by: ArcticMelt2 on July 17, 2019, 03:47:53 AM
https://twitter.com/seaice_de

Quote
#Arctic sea ice is now similar to the year 2012 in terms of total area and extent.
However, the regional pattern is different: the Chuckchi, parts of East Siberian, and Laptev Sea are rapidly melting while there is more ice left in the Barents Sea, Beaufort Sea, and Hudson Bay.

(https://pbs.twimg.com/media/D_n-GwQUYAAVwXh.jpg)
Title: Re: 2019 vs 2012
Post by: FishOutofWater on July 17, 2019, 04:29:26 AM
SST, ice and weather are coupled and non-linear so you need to look at them together, not as independent things and not just in the Arctic. Warming in the north Pacific combined with southerly winds into Alaska has advected heat into the Arctic and the Bering strait over the last 2 years. The loss of ice in that region appears to working its way north, leading to more ocean heat and the potential for more ice loss. This all may be coupling with shifting storm tracks.

Moreover, El Niños are getting stronger releasing more heat. Some of the warm water from an El Niño works it way up the Pacific coast to the coast of Alaska. We can see that effect now on the SST anomaly maps.
Title: Re: 2019 vs 2012
Post by: oren on July 17, 2019, 04:32:15 AM
Cross posting NSIDC sea ice age animations from the melting season thread, for posterity's sake.

* What happened in 2012 between end-June and the late minimum. Lots of old ice was eaten up, especially in the Beaufort/Western CAB. FYI from the direction of Siberia was eaten up despite small initial Laptev bite. Note age was advanced by 1 year in the second image.
* What happened in 2016 between end-June and the early minimum. Lots of old ice was eaten up, especially in the Beaufort/Western CAB.  FYI from the direction of Siberia was eaten up despite small initial Laptev bite.
* Comparing end-June between 2012, 2016 and 2019. This year has much less old ice, and a lot of it is at the border of the Atlantic. With a bit of wind or current, this ice could be gone, the Western CAB could be eaten faster than previous years, and the FYI from Siberia to the pole might offer no resistance, with a larger initial Laptev bite.

Click to animate.
Title: Re: 2019 vs 2012
Post by: El Cid on July 17, 2019, 09:47:59 AM
Uni Bremen misses pics from 2012, the first available is 2012 July 23 (shown on second pic). I compared it to 2019 July 16 (first pic). I know there is still one week to go and the comparison is therefore not totally fair but I would say that 2012 looked much-much worse than 2019
Title: Re: 2019 vs 2012
Post by: Killian on July 17, 2019, 02:21:19 PM
I made these to make my arguments/comments visual as I can be too verbose and am impatient with editing. I wasn't going to post them, but it is being argued elsewhere that the GAC didn't do diddly squat. It certainly did more than did and squat, so far as I can tell.

Hopefully, these help clarify what I think I happened in 2012 and what the real difference was - that week in June and the week of the GAC. Everything else seems to be relatively common, and randomly present or not, for all of the low extent years.

That is, some forcings dominant some years, other forcing dominant others, but 2012 had two anomalous weeks compared to '07 and '16.

Cheers
Title: Re: 2019 vs 2012
Post by: FrostKing70 on July 17, 2019, 02:53:35 PM
Oren,

Looks like the 2019 picture was replaced with a duplicate of the 2012.   Would you please update the post to show 2019?
Title: Re: 2019 vs 2012
Post by: Juan C. García on July 17, 2019, 02:58:20 PM
Oren,

Looks like the 2019 picture was replaced with a duplicate of the 2012.   Would you please update the post to show 2019?
I thought that too, but if you click them, you will notice that they are different.
Title: Re: 2019 vs 2012
Post by: Klondike Kat on July 17, 2019, 03:20:01 PM
Very nice Killian.  You may want to add 2011 for comparison, especially from mid-June through July.
Title: Re: 2019 vs 2012
Post by: FrostKing70 on July 17, 2019, 03:22:45 PM
Yes, you are correct.  I thought they were static, didn't realize they were clickable!
Title: Re: 2019 vs 2012
Post by: gerontocrat on July 17, 2019, 04:16:40 PM
I thought to have another look at 2012, specifically August and the GAC. So no comparison with 2019.

You can see from the graph that in August extent reduced by far more than area. hence dispersion was greatly reduced.
You can see by the gif that the ice that remained at the end of August was far more compact than at the beginning.

That says to me that the 2012 extent minimum flatters to deceive. Remaining ice, though definitely at a record low, was not completely a freak event.

Title: Re: 2019 vs 2012
Post by: gerontocrat on July 17, 2019, 04:45:14 PM
And by the way, when is comes to dispersion, 2019 at the moment is following 2012 pretty closely.
Title: Re: 2019 vs 2012
Post by: philopek on July 17, 2019, 07:26:46 PM
Uni Bremen misses pics from 2012, the first available is 2012 July 23 (shown on second pic). I compared it to 2019 July 16 (first pic). I know there is still one week to go and the comparison is therefore not totally fair but I would say that 2012 looked much-much worse than 2019

One week is a lot of time and then please consider the fact that 2019 does have very little dark purple left where 2012 was still very dark, compact and concentrated.

This hints at something we may have difficulties to asses right now because it's a first of it's kind.
Apparently 90% of the remaining ice is not at 100% concentration anymore but lower, in parts even significantly lower.

Adding this fact and the missing 7 days makes me take your assumption with a grain of salt.

Also we have to be careful not to compare apples with pears. Distribution is much different, the area where a surplus of ice, compared to 2012 is located, (Atlantic side) storms are frequent and violent and can total several weeks in total until the end of the melting season and last but not least, the ice in general is thinner and more fractured.

I'm not saying this is correct and that is not, I'm just saying that one can look at the same picture form more than one side, let's wait and see.

Title: Re: 2019 vs 2012
Post by: Killian on July 18, 2019, 12:06:57 AM
...2012 extent... Remaining ice, though definitely at a record low, was not completely a freak event.

This is a Straw Man argument. I can't recall anyone claiming a freak accident, or even implying it or anything like it.

What I - I won't speak for others, but I get the sense you are responding to my points primarily - have said is the *difference* between '12 and '07/'16 can be explained by the excess -950k loss during two anomalous periods, one of which has not been addressed by anyone. The GAC only accounts for half the difference in final extent. The June massive loss must also be accounted for. All else seems to be mostly explained by general weather variations, all the things we talk about that are dominant one year, not the next and vice-versa. They seem to kind of balance over seasons/years.

'07 lost slowly early then accelerated. '16 lost steadily over a long period of seemingly somewhat higher than average loss, and '12 had two big drops and an extended end of season trough compared to '16's nearly V shape.

That is, it's all just variation, but nothing too specific that is that one big gotcha. 2019 is tracking '11, '16 and '07 pretty well. Then there's '12.

To put this simply, address the average losses the weeks before and after the GAC and the double the average loss the week of the GAC.... or don't. But until someone does, it's all just a bunch of statistics supporting already-held beliefs.

I think two things we can do will help elucidate the 2012 and 2019 seasons differences *and* tell us some interesting things about the ASI in general:

1. What caused the June 6~13, 2012 ASIE 900k+ drop happen? Why do no such drops occur in any other low year, '10, '11, '16?

2. Do we see the same patterns for those two weeks in ASIA? Do any such drops occur in ASIA in any other low year, '10, '11, '16?
Title: Re: 2019 vs 2012
Post by: Killian on July 18, 2019, 12:35:54 AM
Very nice Killian.  You may want to add 2011 for comparison, especially from mid-June through July.

Thanks. 2011 and 2007 are really very similar. They diverge a bit in June and July, and '11 has a nearly perfect inverted bell shape while '07 is skewed a little to the right, but really track quite closely to each other, so '11 doesn't seem to add any info except to reinforce the abnormality that was 2012.

Cheers
Title: Re: 2019 vs 2012
Post by: gerontocrat on July 18, 2019, 06:52:27 AM
...2012 extent... Remaining ice, though definitely at a record low, was not completely a freak event.

This is a Straw Man argument. I can't recall anyone claiming a freak accident, or even implying it or anything like it.

I get the sense you are responding to my points primarily -

Er, no, I was not. Nor to anybody else's. I was responding to that I noticed that while 2012 extent minimum was 800,000 km2 (20%) less than 2016 (the 2nd lowest year), area minimum was only 200,000 km2 (5%) less than 2016, i.e. simply following up my own observation.

Looking at the graphs suggested that this happened in August, and during the GAC. So I had a look at what happened in August to extent and area. The answer was that low concentration ice was destroyed and the remaining ice was left as a compact triangle. Hence area decreased far less than extent and dispersion decreased, instead of increasing until minimum as is "normal".

That makes 2012 very unusual, perhaps unique in the satellite record, freakish, if not a freak. I am debating with myself the extent of 2012's freakishness, not with anyone else. Extent loss from now to minimum in 2012 was 28% more than average, far more than any other year. Freaky. Area loss from now was just 8% above average, not freakish at all.

So 2012 is like the Curate's Egg, freakish in parts.
Title: Re: 2019 vs 2012
Post by: Killian on July 18, 2019, 09:06:22 AM
...2012 extent... Remaining ice, though definitely at a record low, was not completely a freak event.

This is a Straw Man argument. I can't recall anyone claiming a freak accident, or even implying it or anything like it.

I get the sense you are responding to my points primarily -

Er, no, I was not. Nor to anybody else's.

My poor assumption.

Quote
I was responding to that I noticed that while 2012 extent minimum was 800,000 km2 (20%) less than 2016 (the 2nd lowest year), area minimum was only 200,000 km2 (5%) less than 2016,

JAXA and NSIDC, respectively, it seems. Interesting divergence, but 2012 was when most of us realized the future usefulness of extent data was possibly going to be dubious. As you and Friv are pointing out, a lot of loose ice got munched by the conditions then the GAC, so it makes sense, really.

For me, the interesting question is what is most different between the various years that might hint that, when we see that sort of event it might signal something. As I've said, take out those two weeks of extent losses where 2012 falls nearly 1M km, there is virtually no difference with '16, '11, '07. and they all spend big chunks of the year somewhat in sync.

Put another way, if the June drop never happens, the difference is cut in half or more. Why such a big drop that time of year when no other year has a similar drop?  I think we get the GAC thing: Preconditioned ice with extraordinarily dispersed >15% concentration ice that was exterminated by the cyclone. Friv is right about that, as you noted here also. (Whether that ice would have melted anyway is somewhat (a tiny bit) debatable; maybe it would have compacted, etc...)

But, there have been cyclones before and since.... why so different?

And what the heck happened from June 6th to the 13th?

Quote
Extent loss from now to minimum in 2012 was 28% more than average, far more than any other year. Freaky.

Yeah, but you already know why, as you stated above.

In case you haven't seen it, from now till the the end of the post-GAC drop in 2012, Aug 9th, the differential between 2012 and 2018 is only -103k/day vs. 100k/day. Now *that's* weird. Why similar? '18 had pretty steady, nearly monotonic losses while 2012 had really slowed down and was meandering all over, barely losing any extent (though apparently losing a lot of area) until the GAC.

Over 23 days they vary by only 3k a day... wow. You're right, '12 was weird.

What was going on the 2nd week of June?
Title: Re: 2019 vs 2012
Post by: oren on July 18, 2019, 10:26:57 AM
And what the heck happened from June 6th to the 13th?

What was going on the 2nd week of June?
2012 had a lot of extra ice in the Bering, and it went poof. Basically meaningless. When you come from high, you have lots to fall.
And the Kara + Hudson + Baffin + Barents started major losses. And some movement in Beaufort. And the Laptev Opened. My initial bet is that a wind pattern caused some of these losses.

In general, I think looking for patterns in extent is problematic. Extent is not real ice. IMHO area would be much better to analyze (and of course volume/thickness even better, if we had accurate data).
Title: Re: 2019 vs 2012
Post by: bluice on July 18, 2019, 12:39:27 PM
Uni Bremen misses pics from 2012, the first available is 2012 July 23 (shown on second pic). I compared it to 2019 July 16 (first pic). I know there is still one week to go and the comparison is therefore not totally fair but I would say that 2012 looked much-much worse than 2019
I find it interesting that the ”triangle” of ice that remained at Sep 2012 minimum was visible as solid purple ice already in late July. Everything else melted, including the enormous strong purple ridge north of 70N from Beaufort to Chukchi to ESS.

Even though the average ice condition may be better this year than 2012 (which is debatable), the triangle isn’t really solid anymore. There are weaknesses all the way to the pole as well as along the northern shores of Greenland and Ellesmere. Just as preconditioning + weather took everybody by surprise in 2012, I believe that given the right circumstances 2019 might surprise us but in a different way.

I don’t know about extent or area records, but it would be huge to get serious melt and/or polynyas inside the 2012 triangle. That would have far bigger consequences for the future regardless if the record was not made because some areas of, say CAA or Barents, didn’t fully melt this year.

Edit: corrected to 2012 minimum
Title: Re: 2019 vs 2012
Post by: Klondike Kat on July 18, 2019, 01:54:32 PM
And what the heck happened from June 6th to the 13th?

What was going on the 2nd week of June?

In general, I think looking for patterns in extent is problematic. Extent is not real ice. IMHO area would be much better to analyze (and of course volume/thickness even better, if we had accurate data).

It would be nice to have accurate data in these areas.  Until then, extent is the most accurate, as problematic as it may be. 

Title: Re: 2019 vs 2012
Post by: Phil. on July 18, 2019, 02:53:28 PM
Uni Bremen misses pics from 2012, the first available is 2012 July 23 (shown on second pic). I compared it to 2019 July 16 (first pic). I know there is still one week to go and the comparison is therefore not totally fair but I would say that 2012 looked much-much worse than 2019
I find it interesting that the ”triangle” of ice that remained at Sep 2019 minimum was visible as solid purple ice already in late July. Everything else melted, including the enormous strong purple ridge north of 70N from Beaufort to Chukchi to ESS.


I assume you mean 'at Sep 2012 minimum'
Title: Re: 2019 vs 2012
Post by: bluice on July 18, 2019, 03:05:22 PM

I assume you mean 'at Sep 2012 minimum'
Thanks. Now fixed.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 03:41:39 AM
Screenshots from
"Arctic Sea Ice Score Card: Extent, Area, Concentration, Volume, & Thickness - 2019 vs. 2012"
17-page PDF at http://204.197.0.54/MEmodel/NSIDC-PIOMAS2012vs2019-July26.pdf (http://204.197.0.54/MEmodel/NSIDC-PIOMAS2012vs2019-July26.pdf)
(but that server is misbehaving 7/27/2019, should be fixed by Monday).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi65.tinypic.com%2F2a4zf60.gif&hash=9aea2bb3104f80d0a2fc7149c339e178)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi65.tinypic.com%2F2i8ekwx.gif&hash=5440e4f51350e3147988a3f02f2c28de)

2012vs2019 NSIDC concentration images (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi68.tinypic.com%2F2z4wvvk.gif&hash=c8de6df7207dd630a7c1cb2c48d3ba7d)
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 03:55:56 AM
4 more screenshots - Area, Concentration (opposite of Dispersion), Volume, Thickness
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi66.tinypic.com%2F3165kz9.gif&hash=bdfaf4d256ce4755acb8af46eede0a2f)

 (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi64.tinypic.com%2Fl85ya.gif&hash=7cc9074145e8adad0dcb01d9c80f020f)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi65.tinypic.com%2F2zhdwqs.gif&hash=343dce2236851e766aacaaaf9859a88f)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi65.tinypic.com%2F2rhmvmh.gif&hash=a1712680418057d0acfdd64fc6a3dc78)
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 04:08:00 AM
Last of 3 posts (and a half dozen updates to fix glitches).
   Yearly average ratios across Extent-Area-Volume-Thickness
...and the winner (so far) is.... (but you already knew)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F6ti5ab.gif&hash=25303c8d00c5a8c91c400bf359739754)
 
Observations/Speculation: 
   -- 2012 stands alone as the lowest overall with two 1st place and two 2nd place rankings among the four categories.
   -- 2019 is second to lowest, with two 1st, one 2nd, and one 3rd place rankings.  2019 would require a lot of catching up in Extent and Area in the remaining weeks of melt season to take 1st place away from 2012.
   -- 2016 and 2011 are close to each other for 3nd lowest overall ranking, followed by 2017 and 2010 in a virtual tie. 
   -- The sequential rankings of 2010 (#6), 2011 (#4), and 2012 (#1) suggest that the 2012 minimum record was the culmination of a three year sequence of predisposing bad melt years vs. being entirely due to conditions in 2012 alone.
   -- Volume rankings are closely correlated with Extent and Area.  Thickness rankings less so.
   -- Nine of the 10 lowest ranking years have been in the last decade (all except 2007 at #9). 

Definition of terms, caveats, top 20 rankings for each category, and a few other things in the full PDF. Including a still photo from great video of what ice looks like at the edge of the Extent line. https://www.youtube.com/watch?v=EyM06_ZvGbo (https://www.youtube.com/watch?v=EyM06_ZvGbo)
Figure 2.  Ice condition near edge of the Extent limit.  Photo taken at 75N, 150W on October 29, 2016.  Credit: “Waves propagating through Arctic sea ice.”  By IBWOvids. 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi64.tinypic.com%2F154828i.gif&hash=002e623d8f1bb4af2d4c662ffd0f2267)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F67uqgx.gif&hash=73e51fecabf5461e35f6999f76fb09f8)

Lots of calcs involved and done in a hurry, so errors possible.  Corrections and suggestions appreciated.  Now that the spreadsheet is set up, occasional updates should be pretty easy if folks are interested.

Title: Re: 2019 vs 2012
Post by: binntho on July 28, 2019, 07:57:03 AM
Great posts! There is definitely less ice this year than 2012 so far (volume) and it is also thinner even if spread over a smaller extent. But then, area is more or less the same now as 2012.

Exciting to see how this pans out!
Title: Re: 2019 vs 2012
Post by: oren on July 28, 2019, 08:09:21 AM
Thank you GK. Impressive.
Title: Re: 2019 vs 2012
Post by: Neven on July 28, 2019, 12:28:11 PM
Very nice, Glen. That's the way to do it.
Title: Re: 2019 vs 2012
Post by: echoughton on July 28, 2019, 12:42:53 PM
Excellent, Glenn!!
Now are those numbers on the scorecard rankings? Like ...there were 16 other years when the temperature was warmer? 11 other when the volume was less? etc (not sure if I recalled those exact numbers correctly)
Thanks,
Eric
Title: Re: 2019 vs 2012
Post by: cognitivebias2 on July 28, 2019, 02:58:01 PM
Loved your post Glenn.


Not to discount any of the work you've done, but the combined ratios ranking felt a little unfair.  My reasoning is that you have 2 types of ranking, 2D and 3D.  Perhaps the value rather than the ranking is more relevant.

A simple example of how this might look:

2D ratios = f(Ra, Re)
3D ratios = f(Rv, Rt)

Fitness Ranking --> f(f(Ra, Re), f(Rv,  Rt))

EX: 
   Let f(Ra, Re) = avg(Ra, Re)
   Let f(Rv, Rt) = avg(Rv, Rt)
   Let f(f(Ra, Re), f(Rv,  Rt)) = avg(Ra, Re) * avg(Rv, Rt)

2012: 1.035
2019: 1.185
2016: 1.175*1.19 =  1.398
...   

Just a thought, and thanks for the excellent post.

Edit: the 2nd year listed above was supposed to be 2019, changed from a repeated 2012
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 05:18:28 PM
Now are those numbers on the scorecard rankings?

Hi Eric
  Left column of each table is ordinal rank.  Ratio is each year's minimum relative to the all time minimum for that measure.  The projected 2019 volume is the all time low volume, so its ratio for volume is 1.00 (i.e it matches itself).  The 2012 min volume was 5% larger than that so it has a ratio of 1.05 for volume.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 05:55:32 PM
Perhaps the value rather than the ranking is more relevant.

2D ratios = f(Ra, Re)
3D ratios = f(Rv, Rt)

Fitness Ranking --> f(f(Ra, Re), f(Rv,  Rt))

EX: 
   Let f(Ra, Re) = avg(Ra, Re)
   Let f(Rv, Rt) = avg(Rv, Rt)
   Let f(f(Ra, Re), f(Rv,  Rt)) = avg(Ra, Re) * avg(Rv, Rt)

2012: 1.035
2019: 1.185
2016: 1.175*1.19 =  1.398

Hi cognitive
   I just took the simple average of the 4 ratios for each year.  Those ratios are based on values not ranks.

   I can see utility in separating out the 2D and 3D combined ratios.  I don't see advantage of multiplying the 2D * 3D vs. to get the overall combined score vs. just taking the average of the 2D and 3D scores.  They each have two components so every measure gets the same weight by using simple average.  Same is true for multiplying.  I don't think multiplying would change the combined rankings and the final value would be less intuitive, i.e. more difficult to relate to the individual component values.  But if there is an advantage to multiplying 2D * 3D I will consider an explanation for what that advantage is and use if it makes sense to me.

   I thought about differential weighting since Volume seems to me to be the best overall indicator for health of the ice.  But every measure has its pros and cons.

    Extent gets blown up and down by the wind, so in some sense isn't a strong indicator.  But it is the only one that is directly lmeasured.

    Area has more info, but in the full document I repeat cautions from NSIDC about Area getting fooled by melt ponds.

    Volume would be the best if we had a direct measure, but we don't.  We have the PIOMAS model which is an estimate subject to errors as are all model estimates.

    Thickness as I understand it is extrapolated from a relatively small number of direct measures so also has estimate error.

     If I sound like I know what I'm talking about, don't be fooled.  This is just how it all looks to me from reading at NSIDC and PIOMAS sites and ASIF of course.

    By the way, full document did not get the final corrections.  Will try to get the finalized PDF version posted tonight.  The tables shown in the post above have all the corrections I could find. 
     I hope to update all the estimates when the July PIOMAS Volume and Thickness data come out in early August.  I wish there was daily update of PIOMAS Vol and Thick, or even weekly. Great to have Wipneus providing mid month Vol.  Did not see his mid month Thickness value, so most recent I had was from way back in June 30.

    One thing that jumps out to me is the notion that 2012 had help from 2010 and 2011 softening up the ice.  Heading into 2012, 2011 and 2010 were #1 and #2 in the all time combined ranking.  Heading into 2020, it looks like 2018 and 2019 will be #7 and #2 (and 2017 at #5).  Less of a setup than 2012 had. 

    But apart from all the number crunching the big picture is obvious and alarming.  The ship is taking on water, the house is on fire.  Pick your favorite metaphor and talk about what you see in Neven's most excellent ASIF with people you interact with.  Political action requires people talking about it as  the necessary first step. Research shows most people never talk about the climate crisis. Politicians tell me they don't hear much about it from their constituents, and that only the squeaky wheel gets attention and action.  As the AIDS activists realized, silence is death.  It is already too late to prevent bad consequences, but we can prevent worse consequences.  We have to try.
 What else ya gonna do? (end of sermon).
Title: Re: 2019 vs 2012
Post by: cognitivebias2 on July 28, 2019, 06:13:48 PM
Apologies Glen...

I had focused on "
 -- 2012 stands alone as the lowest overall with two 1st place and two 2nd place rankings among the four categories.
   -- 2019 is second to lowest, with two 1st, one 2nd, and one 3rd place rankings.  2019 would require a lot of catching up in Extent and Area in the remaining weeks of melt season to take 1st place away from 2012."

and thought you were using the total of the ranking ordinals rather than the combined ratios to rank years.  I retract my suggestion. 

I should have studied it more before posting. 
Title: Re: 2019 vs 2012
Post by: UCMiami on July 28, 2019, 06:37:12 PM
Ton of data and nicely organized.
It is important to note that the numbers displayed for 2019 are simply applying the average ending to 2019. The numbers missing are the average lost to date for 2011-2018 rather than the average of the total loss to minimum so a percentage loss from maximum at this date is available.

I would have liked to see that number so as to create a ranking of 2019 and then use that concept to adjust 2019 projection based on how 2019 has fared vs. average remaining melt.

That sounds a little convoluted - more simply put: If 2019 melt season to date has been above average, then why project the 2019 end of season as being just average rather than projecting it to be equally above average? Gerontocrat's post for today identifies extent loss for 2019 as 6.9% greater than average from the 2019 maximum. Would it not be more reasonable to use that same 6.9% greater than average loss for the rest of the year.

It is all projection and as they say in investing past performance is no guarantee of future performance but it would make more sense to base the projections on the current year than on an average of past years wouldn't it? There is some validity to the current year building momentum and to the current condition of ice compared to ice from what ice was on average over the past 8 years.

EDIT : I think this was the issue Neven expressed with the NSIDC 2019 projection from a few weeks back - it was simply concluding 2019 would be average at year end, when it was not average to that date.
Title: Re: 2019 vs 2012
Post by: philopek on July 28, 2019, 07:49:58 PM
Ton of data and nicely organized.
It is important to note that the numbers displayed for 2019 are simply applying the average ending to 2019. The numbers missing are the average lost to date for 2011-2018 rather than the average of the total loss to minimum so a percentage loss from maximum at this date is available.

I would have liked to see that number so as to create a ranking of 2019 and then use that concept to adjust 2019 projection based on how 2019 has fared vs. average remaining melt.

That sounds a little convoluted - more simply put: If 2019 melt season to date has been above average, then why project the 2019 end of season as being just average rather than projecting it to be equally above average? Gerontocrat's post for today identifies extent loss for 2019 as 6.9% greater than average from the 2019 maximum. Would it not be more reasonable to use that same 6.9% greater than average loss for the rest of the year.

It is all projection and as they say in investing past performance is no guarantee of future performance but it would make more sense to base the projections on the current year than on an average of past years wouldn't it? There is some validity to the current year building momentum and to the current condition of ice compared to ice from what ice was on average over the past 8 years.

EDIT : I think this was the issue Neven expressed with the NSIDC 2019 projection from a few weeks back - it was simply concluding 2019 would be average at year end, when it was not average to that date.

I second this suggestion because it makes sense, perhaps one could even place the numbers
side by side, means on column with the numbers based on average future melt and another column with the 7% higher melt.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 28, 2019, 11:37:59 PM
If 2019 melt season to date has been above average, then why project the 2019 end of season as being just average rather than projecting it to be equally above average? Gerontocrat's post for today identifies extent loss for 2019 as 6.9% greater than average from the 2019 maximum. Would it not be more reasonable to use that same 6.9% greater than average loss for the rest of the year.
It is all projection and as they say in investing past performance is no guarantee of future performance but it would make more sense to base the projections on the current year than on an average of past years wouldn't it? There is some validity to the current year building momentum and to the current condition of ice compared to ice from what ice was on average over the past 8 years.

I third that idea.  Would be interesting to add to the 2011-2018 avg remaining losses to minimum for parallel projections.  Gets at the issue that Arctic behavior could be in new functional state such that even recent past averages are not the best or at least not the only reasonable expectation for current situation. 

This stuff is certainly interesting, I just wish it did not bring with it such dread.  Great to have community to collectively chew on tthe details and the scary prospects for my kids and all of of us.  Would be even more disturbing to watch this train wreck unfold alone, would be maddening actually. 

mini-speech (again) - I work in the natural sciences (ag & biology), and if people think that the general scientist community is fully aware of the pace and prospects of what's happening our spaceship Earth, my observation is that they would be wrong.  Heck even some of the people I do climate adaptation work with do not fully get the urgency.  The scientists and other smart people I interact with know the basic trajectories, but like like all of us, our  rains focus on the day to day issues.  Hard to save the world between breakfast and dinner.

 The climate crisis is so big that it is hard to react to in specific ways. But we have to take any steps we can to push a survival agenda.  In case it's news, we are heading for deep doo doo friends.

 I'm off topic for this thread and becoming a pain in the butt with yet another iteration of this speech.  Sorry, I just can't help preaching to the choir.  I just hope all us who visit the ASIF will become irritants even if it makes us irritating and predictable to our family, friends and our larger social network.   If not those of us who watch the unfolding epic changes in minute detail, then who else? Thanks for considering this request.  I will try to stick to the data hereafter -- for a while at least.
Title: Re: 2019 vs 2012
Post by: Richard Rathbone on July 29, 2019, 02:05:35 PM
Glen, did you do any testing for negative skill on your techniques? If you use anomaly persistence from far enough out it has negative skill and these look like variants on the that sort of technique.

Using only relatively recent data for comparison may be good enough to avoid that problem, and 2011 makes sense as a starting year, but I wondered if there was any analysis behind that choice.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 29, 2019, 02:29:03 PM
Hi Richard - I chose 2011-2018 simply because those are the most recent years with enough years in the set  - 8 - to get a reasonably well defined (low StdDev) average.  Zero testing.  I did want the epic 2012 in the set.  I now think that it would be good to include 2010 in the recent avg because it was also a big loss year -- #6.
Title: Re: 2019 vs 2012
Post by: Klondike Kat on July 29, 2019, 05:03:07 PM
I did a similar analysis, but went back to 2007, because that was the first big loss year. 

Using NSIDC extent data, the average loss over that time frame was 10.37m km2, with 2012 leading the way with 11.91m, followed by 2008 at 10.71, 2010 at 10.67, and 2007 at 10.61.  2016 was fifth with 10.39m. 

Using the same data on July 19, the average date at which 2/3 of the ice has melted, only 2012 retains its position at 7.78m km2.  2011 and 2013 were next, but both had their melt curtailed at the end of the summer.  Conversely, 2008 was at the low end, but witnessed enhanced melt through late September. 

Consequently, melt to date is a poor indicator of additional melt.  Hence, assuming a continued melt rate through minimum is no better than assuming average melt. 

By the way, using the current rate of melt, the minimum this year would be 3.77m, second lowest after 2012.  Using average melt, the minimum would be a little higher at 3.98m, still second lowest.  However, using the last two years of high early melt (2011 and 2013) as the benchmark for late season melt, then the minimum would be much higher at 4.48m km2. Therefore, my final projection is for a range between 3.77 and 4.48m km2 at minimum.
Title: Re: 2019 vs 2012
Post by: BenB on July 29, 2019, 06:44:44 PM
One of the areas where 2012 had significantly less ice extent on this date is the eastern Beaufort. However, on closer comparison the situation is more nuanced, and arguably 2019 looks more likely to melt out further north. In the event, 2012 then experienced quite strong melt, whereas the forecast is less "favourable" this year, so we'll have to wait and see what happens.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on July 30, 2019, 12:10:47 AM
Consequently, melt to date is a poor indicator of additional melt.  Hence, assuming a continued melt rate through minimum is no better than assuming average melt.

Thanks Klondike.  I think I'll stick with using past average remaining losses from previous years and retract adding the complication of also showing estimates based on this year's anomaly vs. that average. 

Richard Rathbone comment about negative skill by using years from too far back in the average to estimate remaining losses from current date to minimum has me thinking why not just use most recent years as they must be the most relevant in a rapidly and monotonically evolving system.  So instead of 8 prior years, I might go down to the previous 5 years.  Should still be a large enough set to smooth out any single year outlier effect.  I don't really need a small standard deviation for the average.  I'm not doing probability distribution,  just a simple guess at final annual minimum based on average of remaining losses from current date to end of melt season in previous years.

I even thought of using just the most recent 3 years, but that would allow values from flukey conditions in a single year to have too much influence vs. having the average provide a good estimate of what is most likely to occur in the current year. 

I'm just guessing at all of this of course.  Not enough time or expertise to really suss out the best method, but open to suggestions.

Title: Re: 2019 vs 2012
Post by: petm on July 30, 2019, 03:59:03 AM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).
Title: Re: 2019 vs 2012
Post by: jdallen on July 30, 2019, 06:46:18 AM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).
Viewed like this, 2012 doesn't look like it's that far ahead.
Title: Re: 2019 vs 2012
Post by: bbr2314 on July 30, 2019, 06:47:47 AM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).
Viewed like this, 2012 doesn't look like it's that far ahead.
Well, it is actually behind 2019, so that may be why...
Title: Re: 2019 vs 2012
Post by: petm on July 30, 2019, 06:49:31 AM
Viewed like this, 2012 doesn't look like it's that far ahead.

Indeed. Rather 2012 looks considerably and increasingly behind 2019. But what happens in a week when the effects of the 2012 GAC kick in?
Title: Re: 2019 vs 2012
Post by: jdallen on July 30, 2019, 06:51:16 AM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).
Viewed like this, 2012 doesn't look like it's that far ahead.
Well, it is actually behind 2019, so that may be why...
My point, obscured by my attempt at being droll.
Title: Re: 2019 vs 2012
Post by: petm on July 30, 2019, 06:52:01 AM
Oh for a second I read troll...  ;D
Title: Re: 2019 vs 2012
Post by: binntho on July 30, 2019, 06:57:45 AM
Was thinking about the effects of the GAC in 2012 and whether we will be able to prove or disprove that it had a large effect on the minimum that year.

My take is that if we have no GAC this year, then the GAC effect is only proved in the positive (by there not being a new record).

But there is no outcome this year that will be able to disprove the GAC effect since so many other variables are pushing for a record.
Title: Re: 2019 vs 2012
Post by: petm on July 30, 2019, 07:07:25 AM
Was thinking about the effects of the GAC in 2012

I think so too (with the caveat that one point cannot make a trend). If no GAC and the melt slows in the next week or two, it's decent evidence the GAC was important. If no GAC and melt does not slow -- well this year already looks worse so it's hard to say.

My guess is still that the GAC was more imprtant than many people claim, and that as a result we will see a slow-down relative to 2012 starting in about a week and persisting to minimum. But every day I grow less convinced...
Title: Re: 2019 vs 2012
Post by: bbr2314 on July 30, 2019, 07:25:06 AM
Was thinking about the effects of the GAC in 2012

I think so too (with the caveat that one point cannot make a trend). If no GAC and the melt slows in the next week or two, it's decent evidence the GAC was important. If no GAC and melt does not slow -- well this year already looks worse so it's hard to say.

My guess is still that the GAC was more imprtant than many people claim, and that as a result we will see a slow-down relative to 2012 starting in about a week and persisting to minimum. But every day I grow less convinced...
Both GFS and CMC show a significant low pressure event (sub-980mb) in the D7-10 range at 00z. Let's see if 00z EURO follows along.
Title: Re: 2019 vs 2012
Post by: petm on July 30, 2019, 07:42:02 AM
Both GFS and CMC show a significant low pressure event (sub-980mb) in the D7-10 range at 00z. Let's see if 00z EURO follows along.

If we did have a GAC this year (or anything close), I'd be very surprised if we didn't see new extent and area records (possibly by a wide margin).
Title: Re: 2019 vs 2012
Post by: binntho on July 30, 2019, 07:58:20 AM
Both GFS and CMC show a significant low pressure event (sub-980mb) in the D7-10 range at 00z. Let's see if 00z EURO follows along.

If we did have a GAC this year (or anything close), I'd be very surprised if we didn't see new extent and area records (possibly by a wide margin).
I agree - but that would still leave us guessing as to the effect of the GAC or whether all that melt was built in and would have happened anyway.
Title: Re: 2019 vs 2012
Post by: El Cid on July 30, 2019, 08:27:07 AM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).

Wow. I was saying that 2019 gets the silver but on these pictures 2019 looks to be everywhere (except for the Atlantic front) ahead of 2012. Starting to think about that gold medal...
Title: Re: 2019 vs 2012
Post by: BenB on July 30, 2019, 09:50:45 AM
There's a lot of talk about average melt between now and the rest of the season. That's useful for keeping the discussion grounded in reality, but you also have to look at the current conditions:

SSTs - very important to bottom melt in the run-in of the season
volume/thickness - important for obvious reasons
current ice surface conditions/albedo - makes a huge difference to how much insolation is absorbed into the system
dispersion
the weather forecast for the coming week

I would say all of these factors suggest above average melt between now and the minimum. Not necessarily equal to 2012, but almost certainly higher than usual.

For SSTs, last year Neven handily posted a comparison of conditions on 28 July for 4 recent years. I've added 2019. 2012 and 2016 both lost significantly more extent than normal between 28 July and minimum. 2017 and 2018 lost less. Which is 2019 most similar to?

(https://neven1.typepad.com/.a/6a0133f03a1e37970b022ad3a4e1e4200b-pi)
Title: Re: 2019 vs 2012
Post by: sja45uk on July 30, 2019, 12:19:48 PM
For SSTs, last year Neven handily posted a comparison of conditions on 28 July for 4 recent years. I've added 2019. 2012 and 2016 both lost significantly more extent than normal between 28 July and minimum. 2017 and 2018 lost less. Which is 2019 most similar to?

In my biased/unbiased opinion 2019 is closest to 2012 and perhaps more extreme!
Title: Re: 2019 vs 2012
Post by: philopek on July 30, 2019, 08:20:34 PM
For a sense of what may be to come...

Single image of the median of 3 days ending July 28, 2019

vs.

Gif of 5 day lagging median, July 28 - Sept 14, 2012 (click to animate, large file).
Viewed like this, 2012 doesn't look like it's that far ahead.

It's 300k behind today, not ahead and has been a bit less but still ahead on the 28th.

Edit: I see it's a ninja post, this was said further down the quoted post, sorry.
Title: Re: 2019 vs 2012
Post by: philopek on July 30, 2019, 08:24:50 PM
Viewed like this, 2012 doesn't look like it's that far ahead.

Indeed. Rather 2012 looks considerably and increasingly behind 2019. But what happens in a week when the effects of the 2012 GAC kick in?

Since the current gap is around 300k in favor of 2019 and considering 1M loss in 7 days in 2012, an average loss of 100k will bring them to par.

But then the reminder in 2019 will be more fragmented and thinner than 2012. So chances are high that 2019 remains in the lead, especially when putting into account that there are still 3 days to go where 2012 was a stalling a bit and the gap could increase from 300k to 500k even, provided that 2019 won't suffer a similar slow down during the next 3 days which is the unknown today.
Title: Re: 2019 vs 2012
Post by: Klondike Kat on July 30, 2019, 08:26:17 PM
My eyeballing of the five graphs yielding the following ratings for each region from worst (warmest/least ice) to best (coldest/most ice):


Beaufort: 2012, 19, 17, 16, 18
Chukchi:     19, 17, 18, 16, 12
E. Siberian: 17, 16, 19, 18, 12
Laptev:       12, 19, 18, 17, 16
Kara:          16, 12, 19, 17, 18
Barents:      16, 18, 12, 19, 17
Greenland:  16, 17, 18, 12, 19
Baffin:         12, 19, 16, 17, 18

2019 appears to be faring a little better on the Atlantic side, but worse elsewhere.  Anyone else?
Title: Re: 2019 vs 2012
Post by: Sterks on July 30, 2019, 08:36:50 PM
Beaufort: 2012, 16, 19, 17, 18
That image doesn’t make justice to the level of melting going on in Beaufort in 2016.
Title: Re: 2019 vs 2012
Post by: Tor Bejnar on July 30, 2019, 09:55:07 PM
Taking KK's rankings and providing an inverse weighting (1st place gets 5 points, 2nd - 4, etc.), I get "How bad it is" weighted values:

Year   Weighted
          Value
2012     26
2016     27
2017     23
2018     18
2019     26

This makes 2019 look tied with 2012.  2016 'had the potential' but later faded.
Title: Re: 2019 vs 2012
Post by: petm on July 31, 2019, 12:37:35 AM
Since the current gap is around 300k in favor of 2019 and considering 1M loss in 7 days in 2012, an average loss of 100k will bring them to par.

But then the reminder in 2019 will be more fragmented and thinner than 2012. So chances are high that 2019 remains in the lead

I'm not so sure. It seems likely that effects of the GAC lasted for not just a week, but right through to minimum (and beyond).
Title: Re: 2019 vs 2012
Post by: philopek on July 31, 2019, 12:55:29 AM
Since the current gap is around 300k in favor of 2019 and considering 1M loss in 7 days in 2012, an average loss of 100k will bring them to par.

But then the reminder in 2019 will be more fragmented and thinner than 2012. So chances are high that 2019 remains in the lead

I'm not so sure. It seems likely that effects of the GAC lasted for not just a week, but right through to minimum (and beyond).

Agree, I'm also not so sure. I don't dare to look out to far from now because there is so much time left for storms and other things to surprise us ;)

My outlook was meant about 20 days out, should have mentioned it, thanks for this important add-on.
Title: Re: 2019 vs 2012
Post by: BenB on August 01, 2019, 10:38:13 AM
Taking KK's rankings and providing an inverse weighting (1st place gets 5 points, 2nd - 4, etc.), I get "How bad it is" weighted values:

Year   Weighted
          Value
2012     26
2016     27
2017     23
2018     18
2019     26

This makes 2019 look tied with 2012.  2016 'had the potential' but later faded.

Accepting KK's rankings, it's interesting that those results tie in with what actually happened. Correlation, but not necessarily causation. Incidentally, I'd say that 2019 is worse than 2012 in Greenland, and only clearly behind 2016, because although the ice front is slightly further south, there's much more heat in the adjoining waters. But these things are subjective, and in general KK's rankings look about right.
Title: Re: 2019 vs 2012
Post by: Killian on August 03, 2019, 11:38:49 AM
8/01/2019 = -51k
                = 5.91M km sq., a record low for the date.

8/02/2019 = -60k, or 5.85M

Daily Change to Exceed 2012 Record Daily Lows

8/03/2012 = 6.03M km sq.
8/02/2019 = Gain of < 180k km sq. required for the record.

 Call it -65k+/-10k to 5.785 (5.79).

Analysis: I don't see anything that's going to change the daily numbers much for 8/03. We've had a 40k, 50k, and 60k day in the last three days largely because, imo, the wind direction favors expansion of the sea ice, particularly in areas where concentration is low allowing for easy wind effect. That still holds: Winds coming off of the CAA and Greenland aid compaction, but there's precious little space to move with the main ice pack sitting there; winds from Svalbard to Russia generally favor expansion, but the island chain is there and there are some crossing winds muching things up. There's a cyclone straddling the Bering Strait which currently  should be creating a net expansion of ice. Later in the day this one moves north of the CAA and another is entering the Bering Strait... cancelling each other out?

A push. Another middling day mostly because all the mush on the Pacific side and along Siberia should continue melting, plus a little help along the CAA and Greenland.

Caveat: All that mush. A bunch of it could melt away due to the cyclones.

Daily Changes Needed to Exceed 2012 low on Aug. 10. (Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 113.75k km sq. for a record low on this post-GAC date. (9 days.)

I fully expect 2019 to have a higher extent than 2012 sometime between the 5th and 7th, and much more likely the 5th or 6th than the 7th except for the "caveat" above. We could see very little actual ice loss over the next 8 days and still see a huge drop in extent if that mush melts away.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15. (Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 60.68k km sq. for a record low on this date. (45 days)

This still has a fair chance of happening, but gets less likely each day these small meltouts happen. The caveat is... the above caveat. There's an awful lot of low concentration ASI right now and if that all melts out, things will be getting interesting.

Will 2019 get it's "big week in June" and/or "big week in August?"
Title: Re: 2019 vs 2012
Post by: Shared Humanity on August 03, 2019, 02:01:01 PM
nice analysis...
Title: Re: 2019 vs 2012
Post by: Stephan on August 03, 2019, 09:18:39 PM
Yes, I agree. Nice analysis and a 'Like' earned.
Title: Re: 2019 vs 2012
Post by: Killian on August 04, 2019, 12:58:55 PM
8/03/2012 = 6.03M km sq.
8/02/2019 = Gain of < 180k km sq. required for the record.

 Call it -65k+/-10k to 5.785 (5.79).

Came in at... 8/03/19 > 5.785.

No. Effing. Way. And that, Dear Readers, is why we try new things. No, this doesn't mean I've become the Great ASIE Whisperer (more wrong than even within the ballpark so far, I'm pretty sure), but it does say, hey, this may be within the realm of possibility.

All that said...

-----------------------------
Daily Change to Exceed 2012 Record Daily Lows

8/04/2012 = 5.79M km sq.
8/03/2019 = Loss of > 10k km sq. required for the record. (10k is just a round number acknowledging using only two decimal poiints leaves significant daily error.)

Call it -75k +/-15k km sq.

Analysis:

What a tough day to call. We've got a big cyclone crossing from the Beaufort to north of the CAAS/Greenland over the day, thus affecting ice over a wide area and turning wind different directions during different parts of the day.

Early in the day the winds are mostly for expansion, but later in the day more for compaction. And then there's all that mush.

Quote
Caveat: All that mush. A bunch of it could melt away due to the cyclones.

I don't see much change in that mush for what is currently visible on Worldview. Weirdly, the ice in the Beaufort around the US/Can border... isn't moving, or there's an artifiact from the timing of slices of the mosaic. Elsehwhere, it's expanding, going sideways, contracting... holy hell...

What there does seem to be is a lot of heat entering still (by a lot I mean 1 - 5C, depending) according to NullSchool. I think the effects of the large cyclone will manifest more during the following days than the 4th with stirring up a little bit of heat, plus all the arm air around the edges. Honestly, I think this is much more an ASI Area killer than an ASIE killer.

I really don't know what to expect for the 4th. Going with gut as much as anything.... highly scientific... so the large error range.

Daily Changes Needed to Exceed 2012 low on Aug. 10. (Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 121.43k km sq. for a record low on this post-GAC date. (9 days.)

Quote
I fully expect 2019 to have a higher extent than 2012 sometime between the 5th and 7th, and much more likely the 5th or 6th than the 7th except for the "caveat" above. We could see very little actual ice loss over the next 8 days and still see a huge drop in extent if that mush melts away.

Nothing new here to say.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15. (Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 60.70k km sq. for a record low on this date. (45 days)

Nothing new here to discuss...
Title: Re: 2019 vs 2012
Post by: Neven on August 04, 2019, 02:48:11 PM
2019 warmer overall than 2012 during July, much warmer on Atlantic, slightly more warming on Pacific, cooler on Siberian, much cooler on Canadian:
Title: Re: 2019 vs 2012
Post by: Killian on August 04, 2019, 03:36:57 PM
Positive feedback appreciated. Part of the reason I do this is these are numbers that work for me, that I want to see, so I assumed at least a few others would, also.

As they say, and as a teacher, I mean it, if I help even one...

Cheers
Title: Re: 2019 vs 2012
Post by: Yuha on August 04, 2019, 03:52:51 PM
Positive feedback appreciated.

The ice disagrees.  ;D
Title: Re: 2019 vs 2012
Post by: Killian on August 05, 2019, 03:34:49 AM
Positive feedback appreciated.

The ice disagrees.  ;D

No kidding. Think we're near the limit for positive feeback loops.
Title: Re: 2019 vs 2012
Post by: Killian on August 05, 2019, 06:59:36 AM
Call it -75k +/-15k km sq.

Another reasonably good call. ASIE dropped 70k (about 66k actual, I think) to 5.72, within my *generous* margin of error. Nice, though, that the rounded error is within 5k since I use the rounded numbers from the JAXA graph. Even the unrounded came in at less than a 10k deviation and I usually use a 10k +/- error . I think we get to call this a victory, eh?

Note on Method:

1. Look at wind directions and temps via Nullschool. Primary data.
2. Look at Worldview actual ice movement. Mostly the previous day's ice, but I can see a little of the day being predicted at the time I predict, which can help confirm the wind forecasts.
3. Look at info posted by others on the forums here, so whatever others happen to post.

This is enough to get reasonably accurate predictions on occasion. I've not been able to make it any more sophisticated than that, so far, but for extent, wind, currents and bottom melt will be key because we don't need any change in area or volume to get changes in extent; ice movement is enough, so ultimately I decided winds are the central data needed. Energy in the system - heat - is likely what I'd look at for area with storms next.

FYI, in case anyone is curious and it wasn't already obvious.

-----------------------------

Daily Change to Exceed 2012 Record Daily Lows

8/05/2012 = 5.65M km sq.
8/04/2019 = Loss of > 70k km sq. required for the record.

*Note the very large 140k drop for 2012.*

Call it -85k +/-10k km sq.

Analysis:
There seems to be/may be a lot of the slush ice melting because of the high temps flowing in to the Chukchi, ESS, Laptev and Beaufort Seas. And that, quite simply, tells the tale for 8/05.

Looks like 2019 has at least a 50% chance of retaining the record one more day. No more than that, I'm fairly certain. Look for '19 and '12 to be very, very close on the 5th. If my prediction is correct, '19 should be lower by a smidgen.

Daily Changes Needed to Exceed 2012 low on Aug. 10. (Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 129.83k km sq. for a record low on this post-GAC date. (7 days.) (Sorry... yesterday's was 8, not 9.)

Done. This just isn't going to happen. However, with the reduction - if my prediction holds - and the fluff in the Chukchi and Beaufort starting, on the 5th, to really diminish, it's worth watching to the end. The way the extent edge is determined means there's a lot of area that can suddenly disappear still.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15. (Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 60.45k km sq. for a record low on this date. (42 days) <-- Also wrong yesterday.

Without some big days over the next week, it gets a lot less likely '19 challenges the record. that number has to be down to 20k by Sept 1.
Title: Re: 2019 vs 2012
Post by: petm on August 06, 2019, 01:33:23 AM
Looks like we'll be getting something of an answer to the controversy over how important the GAC was to the record melt in 2012. This date in 2012 was when the GAC hit and the melt rate (area/extent decline), which had been starting to shallow out like most years, picked up again.

This year, although it's difficult to directly compare years, today we have nearly equal area, extent and PIOMAS volume as 2012. And we have no major storms in the forecast. So, if area/extent begin shallowing out now (at least until a storm hits if one does), as seems very likely to me, does it provide evidence that the 2012 GAC was decisive or at least important in the 2012 records?

Aug4 2019 vs. 2012, 5-day lagging median, cross-fade gif att. (Click)
Title: Re: 2019 vs 2012
Post by: oren on August 06, 2019, 03:06:36 AM
So, if area/extent begin shallowing out now (at least until a storm hits if one does), as seems very likely to me, does it provide evidence that the 2012 GAC was decisive or at least important in the 2012 records?
IMHO that would not be enough evidence. As Friv says, 2012 was primed to lose a lot of vulnerable ice on the ESS side. The thing is, 2019 is in the same situation, though the amount of ice on the block is somewhat lower. So should a GAC come along, all that ice is gone in a flash, but if no GAC arrives, that ice will still melt out in a couple of weeks. So immediate slowdown vs. 2012 is not proof enough - it shows the GAC brought the melt forward, not that it made a difference to the record.
The question is: does it take a GAC to sustain melt momentum into late August and Sept. in 2012 and 2016 the GACs were the immediate suspects of such late melting, what we need is 2019 to serve as the control group - lots of warmth, lots of momentum, no GAC, possibly season tapers off and dies down. Good for the ice, good for the experiment. Still not sure it will happen though - there could be a GAC, or there could be continued melt without a GAC. We'll know in a few weeks.
Title: Re: 2019 vs 2012
Post by: peterlvmeng on August 06, 2019, 03:31:01 AM
So, if area/extent begin shallowing out now (at least until a storm hits if one does), as seems very likely to me, does it provide evidence that the 2012 GAC was decisive or at least important in the 2012 records?
IMHO that would not be enough evidence. As Friv says, 2012 was primed to lose a lot of vulnerable ice on the ESS side. The thing is, 2019 is in the same situation, though the amount of ice on the block is somewhat lower. So should a GAC come along, all that ice is gone in a flash, but if no GAC arrives, that ice will still melt out in a couple of weeks. So immediate slowdown vs. 2012 is not proof enough - it shows the GAC brought the melt forward, not that it made a difference to the record.
The question is: does it take a GAC to sustain melt momentum into late August and Sept. in 2012 and 2016 the GACs were the immediate suspects of such late melting, what we need is 2019 to serve as the control group - lots of warmth, lots of momentum, no GAC, possibly season tapers off and dies down. Good for the ice, good for the experiment. Still not sure it will happen though - there could be a GAC, or there could be continued melt without a GAC. We'll know in a few weeks.

Oren, I think the storm comes from either warmer SST or cold troposphere. As you can see storm form frequently in the periphery of arctic region because of warm SST. In 2016, the troposphere in Arctic is not warm maybe even cold so we also see lots of storm. As the arctic SST is rising and troposphere is cooling. Trust me, we will see numerous strong cyclone in arctic region in the late August.
Title: Re: 2019 vs 2012
Post by: petm on August 06, 2019, 03:50:14 AM
As Friv says, 2012 was primed to lose a lot of vulnerable ice on the ESS side.

I'm ambivalent about this proposition. It seems to suggest that a *slower* melt on the periphery (or at least the ESS) should lead to a lower minimum. Also, this year has more vulnerable ice in the Beaufort, CAB, Atlantic, and Greenland sea. If 2012 had not had the GAC, wouldn't that ESS ice have been protective of the adjacent CAB ice. Look how long it's taking the few final wisps of the ESS to melt out this year compared to how suddenly the far more substantial ESS ice melted out in 2012.

Quote
The question is: does it take a GAC to sustain melt momentum into late August and Sept. in 2012 and 2016 the GACs were the immediate suspects of such late melting, what we need is 2019 to serve as the control group - lots of warmth, lots of momentum, no GAC, possibly season tapers off and dies down.

I'd say yes, and that it is not a separate question from the question of immediate melt. Sure, we shall see...
Title: Re: 2019 vs 2012
Post by: Alphabet Hotel on August 06, 2019, 04:54:17 AM

Oren, I think the storm comes from either warmer SST or cold troposphere. As you can see storm form frequently in the periphery of arctic region because of warm SST. In 2016, the troposphere in Arctic is not warm maybe even cold so we also see lots of storm. As the arctic SST is rising and troposphere is cooling. Trust me, we will see numerous strong cyclone in arctic region in the late August.

That's my gut feeling as well. All that heat has to go somewhere, and a storm (or storms) are the usual way to dissipate it.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 06, 2019, 09:01:21 AM
    Arctic Sea Ice Scorecard updated for Extent and Area through August 4.
Part 1 of 3 posts. 
     Still using 2011-2018 average losses from current date to September minimum as baseline for predicting 2019 minimums. 
    Post by Klondike Kat indicated that season to date anomaly vs. average loss rate was not a good predictor for remainder of year losses.  KK data also indicated that due to variability between years, using a more recent but smaller set of years would not give a reliable average.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi67.tinypic.com%2Fngbxcj.gif&hash=39becf272423f8d627729a29bcfe1fa8)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi67.tinypic.com%2F2wnz7lu.gif&hash=4db080930d4c4b968ee049ebf13e9dcf)


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi67.tinypic.com%2F2aki8sn.gif&hash=3f5faf384dbdef7e2f0e5d51f15b4fb5)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F6nz87p.jpg&hash=0fa8c56405f5d4b22aee958c337d0632)

Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 06, 2019, 09:07:50 AM
Arctic Sea Ice Scorecard --  Volume and Thickness* values updated through July 31.
Post 2 of 3.
  (* There was an error in Thickness values in the first scorecard posted on July 26.  Thickness values corrected in this edition.)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F2cypr0x.gif&hash=b96fa122ebea7266a977fee7ff8e254e)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi68.tinypic.com%2F2q0u649.gif&hash=0e3c14eadeb6142af76518ad44c1e1a2)
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 06, 2019, 09:59:09 AM
Arctic Sea Ice Scorecard
Post 3 of 3.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi68.tinypic.com%2Fvo9aba.gif&hash=68a6dcef51f2ac30928068c2ac8a300a)

Observations/Speculation: 
-- 2012 stands alone as the lowest overall with 1st place ordinal rankings for all four measures.  (Technically, 2019 minimum thickness was lower, but only by insignificant margin.) 
The index value for each year is based on its average of ratios to the minimum value observed in 1979-2019 for each measure, not by the average ordinal ranking.

-- 2019 is second to lowest, with one 1st, and three 2nd place rankings.  The estimated 2019 minimums for Extent and Area are substantially larger than for 2012.  The 2019 and 2012 minimums for Volume and Thickness are similar. 

-- 2016 and 2011 are close to each other for 3nd lowest overall ranking, followed by 2010 and 2017 in a virtual tie for 4th place. 

-- Heading into 2012, the prior two years -- 2010 and 2011  -- were ranked #2 and #1 (now 5 and 4), which suggests that the 2012 minimum records may have been the culmination of a three year sequence of predisposing bad melt years vs. being entirely due to conditions in 2012. 
 
-- Except for 2007, there is a high degree of congruence between the 2D measures (Extent, Area) and the the 3D measures (Volume, Thickness). 

-- Nine of the 10 lowest ranking years have been in the last decade (all except 2007 at #9).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi66.tinypic.com%2Fwhe2o6.gif&hash=d006bc3f25efa46af41e599693a53b41)

This report is not sanctioned by the National Snow and Ice Date Center, the Polar Science Center, or any other institution.  This report is a personal effort to make the situation of Arctic sea ice decline easier to understand as an indicator for the rapidly progressing and accelerating planetary climate crisis. 

Perspectives:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi65.tinypic.com%2F2vuarzk.gif&hash=bd44c5a60ce798e48b1c8492592dc380)

---------------------

The following image shows Arctic albedo loss across 7 years. 
But it is outdated now because it only includes 3 of the top ten smallest minimum Extent years.  Current albedo reductions relative to a 2000-2004 baseline must be much higher.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi68.tinypic.com%2F2qn3zn4.gif&hash=da2ad2fde4860eb3fb21692356693bab)
Title: Re: 2019 vs 2012
Post by: philopek on August 06, 2019, 12:48:49 PM
@glen

Absolutely top notch contribution, one of the most impressing I've seen kudos.

Perhaps a remark that doesn't mean to take anything away from the data you provided, just
slightly different angle from where i look at things:

- We shall see most certainly ABOVE average melt, not just average

To me that means that we shall see a tighter race while i currently see the final result like your
calculations do, just tighter and i could imagine that volume will be lowest this year, not only thickness.

Title: Re: 2019 vs 2012
Post by: Killian on August 06, 2019, 01:01:26 PM
8/04/2019 = Loss of > 70k km sq. required for the record.

There seems to be/may be a lot of the slush ice melting because of the high temps flowing in to the Chukchi, ESS, Laptev and Beaufort Seas. And that, quite simply, tells the tale for 8/05.

Call it -85k +/-10k km sq.

Correct analysis, wrong number. Fell 107k to 5.61M km sq., 12k more than my max. Encouraging: Got the increased melt,/lower extent right.

Daily Change to Exceed 2012 Record Daily Lows

8/06/2012 = 5.49M km sq.
8/05/2019 = Loss of > 120k km sq. required for the record.

*Note the very large 160k drop for 2012.*

Call it -75k +/-10k km sq.

And, that, Dear Readers, would be the end of 2019's record run, likely for the rest of the melt season. With the huge drops coming for 2012, there's really no chance 2019 holds the record after the 6th, but we could see that 120k given the 5ths 107k. But don't count on it.

Analysis:
Quote
There seems to be/may be a lot of the slush ice melting because of the high temps flowing in to the Chukchi, ESS, Laptev and Beaufort Seas. And that, quite simply, tells the tale
for 8/06, too. The difference is a lot less balance in wind directions supporting compaction vs expansion. Temps are pretty high in the Laptev and Chukchi, the only areas with solid chances of compaction, flowing into the ice, though, and some of the strongest winds for the day flow in those two areas.

The caveat is, as always, that wispy mush melting or not. Could have a huge drop if it goes poof. 150k? Worldview suggests it isn't going to happen on the 6th, though.

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 134k km sq. for a record low on this post-GAC date. (5 days.)

Despite the 107k loss for the day, the daily average rose bc of the large drop, and there are 5 straight 100k+ days coming with a 150k, 160k, and a 190k day all ahead.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 59.27k km sq. for a record Sept. low. (41 days)

After 7 days sitting at 60k, the avg finally dropped to 59k, but without some big days over the next week, it gets a lot less likely '19 challenges the record.
Title: Re: 2019 vs 2012
Post by: Klondike Kat on August 06, 2019, 03:12:35 PM
@glen

Absolutely top notch contribution, one of the most impressing I've seen kudos.

Perhaps a remark that doesn't mean to take anything away from the data you provided, just
slightly different angle from where i look at things:

- We shall see most certainly ABOVE average melt, not just average

To me that means that we shall see a tighter race while i currently see the final result like your
calculations do, just tighter and i could imagine that volume will be lowest this year, not only thickness.

Agree.  Glen did an excellent job.  I believe in his calculations that he is using above average melt, as he is assuming that the melt to date (which is above average) will constitute the same overall fraction of the total melt as previous years.  I am curious to see how his numbers match with the final tally.
Title: Re: 2019 vs 2012
Post by: binntho on August 06, 2019, 03:21:57 PM
Agree, very interesting.
Title: Re: 2019 vs 2012
Post by: philopek on August 06, 2019, 03:24:21 PM
@glen

Absolutely top notch contribution, one of the most impressing I've seen kudos.

Perhaps a remark that doesn't mean to take anything away from the data you provided, just
slightly different angle from where i look at things:

- We shall see most certainly ABOVE average melt, not just average

To me that means that we shall see a tighter race while i currently see the final result like your
calculations do, just tighter and i could imagine that volume will be lowest this year, not only thickness.

Agree.  Glen did an excellent job.  I believe in his calculations that he is using above average melt, as he is assuming that the melt to date (which is above average) will constitute the same overall fraction of the total melt as previous years.  I am curious to see how his numbers match with the final tally.

Ok, thanks, that evaded me, perhaps the frequent occurrence of the word "average" made me partially blind for details. Your help is much appreciated.
Title: Re: 2019 vs 2012
Post by: dnem on August 06, 2019, 07:16:19 PM
It looks to me like he's using the average 2011-2018 melt to make his prediction.  Extent on August 4, 2019=5.76, Average melt from 2011-2018= 1.87, 5.76-1.87=3.89.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 06, 2019, 08:21:34 PM
Right dnem. 
I used the 2011-2018 average reduction from latest observation date to the value at Sept. minimum Extent/Area/Volume/Thickness for those years and subtracted it from the value 2019 had on latest observation date.

Prior posts discussed idea of extending currently season anomaly above (or below, if that were the case) the 2011-2018 losses until the end of the melt season.  Thus, if 2019 losses were 5% greater than average losses from start of melt season to latest 2019 observation date, then the average 2011-2018 losses until minimum would be multiplied x 105%.

That seemded like a good idea until Klondike Kat showed an analysis that the anomaly above average melt rates in early season was NOT a good predictor of higher melt rates for remainder of season.  So I stuck with the original method.  That makes sense in that just because June was above average warmth/sunshine etc., that does not mean August will be too.  Just because a stock went up Tue. doesn't mean it will keep going up Wed, Thur, Fri.

But as is often discussed in the ASIF, "melting momentum" is a real thing.  Once ice gets preconditioned by strong melting forces, accelerated melt rate can continue for a long time afterward.

I am going to stick with the simple 2011-2018 average remaining losses as the most reliable predictor for remainder of current year (just my guess), and it is simple to understand.  But I can add a second 2019 estimated Sept. minimum value for Extent/Area/Volume/Thickness that pays heed to melting momentum.  I can do that by dividing the year to date 2019 losses for each measure by the 2011-2018 average for those dates to get the anomaly percentage for 2019 Ext/Ar/Vol/Thick losses up to current date.  Then use those anomaly percentages to multiply x the 2011-2018 average losses for remainder of year to create another estimate for 2019 that assumes continued ice loss anomaly.  I can add them to table without an ordinal number so as not to mess up the rankings by having two ordinal ranks for a single year.  But it's location in the table would show all that anybody wants to know -- how does 2019 compare to 2012 and other years.

Can't do it now, out of time.  But after August 14 which marked the end of GAC in 2012, another update comparing 2019 to 2012 and other years would be interesting and I can show estimates for 2019 minimums using both methods.

Sorry that the 2012 vs 2019 NSIDC conc. map posted so large.  First time I saved it, the size was normal, as is the 1980 vs 2012 Sept. min. image.  I don't know how to control size of the image when added to forum post.
Title: Re: 2019 vs 2012
Post by: philopek on August 06, 2019, 09:05:35 PM
Right dnem. 
I used the 2011-2018 average reduction from latest observation date to the value at Sept. minimum Extent/Area/Volume/Thickness for those years and subtracted it from the value 2019 had on latest observation date.


That is closing the gap significantly and only volume remains kind of to tight to tell then.

Thanks for elaboration ;)

Good job either way as mentioned ;)
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 07:11:18 AM
I used the 2011-2018 average reduction from latest observation date to the value at Sept. minimum Extent/Area/Volume/Thickness for those years and subtracted it from the value 2019 had on latest observation date.

You've probably addressed the issue of why those years, but I don't have time to read back through all your posts, sorry. I see 2011's level as a result of the momentum from the phase change and conditioning of 2005~2010. Weather in 2007 and 2010 (less so) was highly anomalous, but I think the preconditioning of the time period partly made 2011 possible.

2012 is a true statistical anomaly in the truest scientific sense. Had it been a normal part of anything we'd have approached those numbers again at some point in the last 7 years. That is, have you considered simply dismissing 2012 and/or assigning it an average?

There is a very important, never-discussed issue that is a pet of mine. Both 2012 and 2016 were strong El Nino years. The scientific literature in 2012 said EN's do not affect ASI. They're wrong, IMO. As you can see here...

Quote
I went further back, eyeballing from an extent graph through 2010 or so with poor detail (what I could find) and a list of ENSO years and intensities. This is the rough. If anyone has more detailed resources and can nail this down better, please do.

Here is what I found going all the way back to the beginning of ASIE decline @ 1953-ish.

EN ’51 – ’54 = inception of ASI Extent decline.
EN ’57 – ’59 = Near New Low/New Low
EN ’65 – ’66 = Near New Low/New Low
EN ’68 – ’70 = New Low
EN ’72 – ’73 = possible correlation, some delay
EN ’76 – ’78 = New Low
EN ’79 – ’80 = New Low
EN ’82 – ’83 = New Low
EN ’86 – ’88 = New Low (’89,’90)
EN ’94 – ’95 = New Low
EN ’97 – ’98 = Drop from Previous (?)
EN ’04 – ’05 = Near New Low/New Low
EN ’04 – ’05/’06 – ’07 = New Low
EN ’09 – ’10 = New Low (’10, ’12)
EN ’15 – ’16 = New Low ’16,’17?
http://www.realclimate.org/index.php/archives/2015/08/unforced-variations-aug-2015/comment-page-5/#comment-635199

...I predicted the near new low (2nd in the record) of 2016 a full year ahead, in August 2015. How? An EN was brewing and was expected to be strong. I looked back through the data all the way back to the 1950's and noticed a correlation between ENs and ASI changes. However, as we know, it takes time for energy to propogate through a system, particularly the oceans. It was when I used a two-year post-EN window that the correlation jumps out. The year of the EN it is occurring during the melt season, but in the Pacific, not the Arctic. It takes time for that energy to propagate and takes time for ice to react. Bottom melt, as we all know, dominates.

Since 2012, and since my theory was posited 4 years ago, two studies have found that Pacific heat and moisture affect ASI. The tie is not as equivocal as my theory, but nobody is looking at my theory because the conventional wisdom EN's don't affect ASI is set. But they do, imo. The combination of the EN, the GAC and the high export gave us 2012. It's not normal. As any good scientist is taught, sometimes you have to throw out the outlier. It does not serve as a good model for a year with no GAC, no EN (though June's and July's high heat might be considered proxies for the EN), and higher but not exceptional export.

That is, I wonder if your method might consider using the clear phase change that came after the EN of 2015/2016 given the clustering of patterns since that time.

FYI, FYC (for your consideration).

Cheers
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 07:22:14 AM
<snip>
There is a very important, never-discussed issue that is a pet of mine. Both 2012 and 2016 were strong El Nino years.
</snip>
Well, 2012 certainly wasn't a "strong El Nino year", in fact the beginning of 2010 to the end of 2014 saw two back-to-back La Ninas followed by a child-free period of almost 3 years.
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 07:39:33 AM
<snip>
Quote
I went further back, eyeballing from an extent graph through 2010 or so with poor detail (what I could find) and a list of ENSO years and intensities. This is the rough. If anyone has more detailed resources and can nail this down better, please do.

Here is what I found going all the way back to the beginning of ASIE decline @ 1953-ish.

EN ’51 – ’54 = inception of ASI Extent decline.
EN ’57 – ’59 = Near New Low/New Low
EN ’65 – ’66 = Near New Low/New Low
EN ’68 – ’70 = New Low
EN ’72 – ’73 = possible correlation, some delay
EN ’76 – ’78 = New Low
EN ’79 – ’80 = New Low
EN ’82 – ’83 = New Low
EN ’86 – ’88 = New Low (’89,’90)
EN ’94 – ’95 = New Low
EN ’97 – ’98 = Drop from Previous (?)
EN ’04 – ’05 = Near New Low/New Low
EN ’04 – ’05/’06 – ’07 = New Low
EN ’09 – ’10 = New Low (’10, ’12)
EN ’15 – ’16 = New Low ’16,’17?
http://www.realclimate.org/index.php/archives/2015/08/unforced-variations-aug-2015/comment-page-5/#comment-635199
This list seems strangely incomplete, right from the start there is an error in counting the two ENs of 1951 and 1953 as one and the 1963 EN is not mentioned. The EN events are also vastly different, 76-78 saw two small ENs, 79/80 an almost non-EN while the 1982/3 was a decent sized one and 88-86 a real humdinger.

A good overview of the appearances of the two siblings can be found here https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

As for the claims on lows extent wise (going by the following graph from https://sites.google.com/site/arcticseaicegraphs/longterm), 82 or 83 certainly did not see any new lows, nor did 86, 87 or 88.

The first claim that I find that could be said to be in the ballpark is that 1995 seems to have matched the previous record from 90 (which by the way is not included in the claims above).

Eyeballing graphs with bad resolution is not a good method, and I for one am not convinced that there is a causal link between El Ninos and low sea ice minimums, but I'm open to the possibility.
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 08:15:59 AM
Took it here https://forum.arctic-sea-ice.net/index.php/topic,2274.msg219815.html#msg219815
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 07, 2019, 12:34:53 PM
very lazy superimposition of both data sets

[sorry the jpeg of that was horrible quality]

[edit, theyre both awful  8) ]
Title: Re: 2019 vs 2012
Post by: DrTskoul on August 07, 2019, 12:36:34 PM
I don’t really see any correlation...
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 07, 2019, 12:41:02 PM
I don’t really see any correlation...

One may argue that a la nina precedes a recovery, I may plot this properly in R
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 12:45:06 PM
I don’t really see any correlation...

One may argue that a la nina precedes a recovery, I may plot this properly in R
Let's take this out of here and over here https://forum.arctic-sea-ice.net/index.php/topic,2274.msg219815.html#msg219815
Title: Re: 2019 vs 2012
Post by: Archimid on August 07, 2019, 01:05:04 PM
When considering the influence of teleconnections it is important to consider that the Arctic is not the same system in the 2010's than it was in the 20th century.

When the ice was thick, extent large and the jetstream strong and stable and when ENSO was not being fed by decades of AGW  the correlation was different than it is now.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 02:40:58 PM
<snip>
There is a very important, never-discussed issue that is a pet of mine. Both 2012 and 2016 were strong El Nino years.
</snip>
Well, 2012 certainly wasn't a "strong El Nino year", in fact the beginning of 2010 to the end of 2014 saw two back-to-back La Ninas followed by a child-free period of almost 3 years.

Sorry. It was the "moderate" '09-'10 EN. As I said, a 2-year window. Ended in 2010, low in 2010 and 2012, fitting the theory.

Thanks for the correction, but full context is important.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 02:43:37 PM
I went further back, eyeballing from an extent graph through 2010 or so with poor detail (what I could find) and a list of ENSO years and intensities. This is the rough.

This list seems strangely incomplete, right from the start there is an error in counting the two ENs of 1951 and 1953 as one

Sorry, not the case. Note the start date of the Mauna Loa data...

Quote
and the 1963 EN is not mentioned.

Look at the list. Why wouldn't it have been? The issue is not how EN's *don't* affect the ASI....

Etc.

Your feedback is in error. Could you check your comment then repost? Or, when I have more time and have had less beer, I will address them. Do note the post is from four years ago, so I am unlikely to remember every decision made then, and errors are certainly likely.

Cheers
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 02:56:50 PM
When considering the influence of teleconnections it is important to consider that the Arctic is not the same system in the 2010's than it was in the 20th century.

When the ice was thick, extent large and the jetstream strong and stable and when ENSO was not being fed by decades of AGW  the correlation was different than it is now.

Yup. And I called 2016, anyway. EN is a global phenomenon which I think makes it a meta, not macro, input to the system.
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 02:57:26 PM
<snip>
Quote
I went further back, eyeballing from an extent graph through 2010 or so with poor detail (what I could find) and a list of ENSO years and intensities. This is the rough.

This list seems strangely incomplete, right from the start there is an error in counting the two ENs of 1951 and 1953 as one

Sorry, not the case. Note the start date of the Mauna Loa data...

Quote
and the 1963 EN is not mentioned.

Look at the list. Why wouldn't it have been? The issue is not how EN's *don't* affect the ASI....

Etc.

Your feedback is in error. Could you check your comment then repost? Or, when I have more time and have had less beer, I will address them. Do note the post is from four years ago, so I am unlikely to remember every decision made then, and errors are certainly likely.

Cheers
Ciao Killian, in a few hours it's gonna be the beers on this side of the globe. Don't worry too much, it's not an important issue - but I did check against the actual numbers to which I've included links. Other than that, I think we should move this discussion, which is off topic for this thread, to here: https://forum.arctic-sea-ice.net/index.php/topic,2274.msg219815.html#msg219815
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 02:58:44 PM
I don’t really see any correlation...

One may argue that a la nina precedes a recovery, I may plot this properly in R
Let's take this out of here and over here https://forum.arctic-sea-ice.net/index.php/topic,2274.msg219815.html#msg219815

No. For obvious reasons.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 03:00:13 PM
I don’t really see any correlation...

One may argue that a la nina precedes a recovery, I may plot this properly in R

Interesting. I only considered them as related to lows and there was zero correlation. Literally in the 50/50 range.
Title: Re: 2019 vs 2012
Post by: binntho on August 07, 2019, 03:01:15 PM
I don’t really see any correlation...

One may argue that a la nina precedes a recovery, I may plot this properly in R
Let's take this out of here and over here https://forum.arctic-sea-ice.net/index.php/topic,2274.msg219815.html#msg219815

No. For obvious reasons.
Well, this has nothing to do with 2012 vs. 2019 and it's just one of those silly bickerings about minor points of interest. So let's do the bickering where the bickering belongs.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 03:08:02 PM
Quote from: binntho link=topic=2792.msg219860#msg219860 date=1565182646is
Ciao Killian, in a few hours it's gonna be the beers on this side of the globe.

It *is* the beers where I am, so consider that WRT my post quality.

Quote
it's not an important issue

Unless it is...

Quote
...which is off topic for this thread

Well.... the idea is not to prove or disprove my theory, but to give someone else the chance to improve their model. That is, the main point is helping Glen constrain which years to include in his modeling/analysis. I suppose we should let him chime in?
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 07, 2019, 04:11:21 PM
No analysis.  I simply used 2011-2018 because 8 years is enough to get a reasonably defined average.  And those are the most recent years, so the best we have to reflect any functional changes in the system.  I wanted 2012 in the mix because it happened once so it can, and likely will, happen again.  But by being mixed in with 7 other years, 2012 is only a partial influence.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 04:48:43 PM
Correct analysis, wrong number.

History repeats. I said...

Quote
Call it -75k +/-10k km sq.

but it came in 16k lower than my lowest possible at 5.51M, for the reasons stated, so far as I can tell. I also said...

Quote
And, that, Dear Readers, would be the end of 2019's record run, likely for the rest of the melt season.

...and damned if the two didn't cross, though at a little lower level. (The lesson I would share here is patterns, while not everything, are something, and having what we in permaculture call "pattern literacy" is vital to analysis. Not a hard call, right? However, I did first make a little while back.)

Daily Change to Exceed 2012 Record Daily Lows

8/07/2012 = 5.38M km sq.
8/06/2019 = Stands at 5.51M. Loss of > 130k km sq. needed to set a daily record for this date.

Analysis: What stands out is how the ice is not responding strongly to the winds, but seems to be driven by the melt momentum almost exclusively bc the winds in no way supported a drop so large, but the melt season and surface temps did.

For 8/07/19? Not a clue. Worldview is all clouds. SST's are only high on the Pacific side... where much of the junk ice is. Winds indicate compaction on the Pacific side and expansion from Greenland to Siberia.

I really don't know where the 110k came from except melt. Seeing the visible movement on the Atlantic side for expansion and the negligible movement on the Pacific side, but keeping in mind momentum... Let's weight it towards little stuff saying their goodbye's and call it...

-90k+/-10k.

On the positive side of things, 2019 did give up the lead to 2012 as predicted, and I hold, shakily, to the contention that that's it for 2019 in terms of a possible new minimum.

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 142.5k km sq. for a record low on this post-GAC date. (4 days.)

This has become absurd. 2019 cannot meet 2012's low on Aug. 10. I'd put every cent I have on that. Four days over 142k? Yeah, right. I'll ride this horse to the end, but... just to follow through.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 58.24k km sq. for a record Sept. low. (40 days)

Meh... still within the realm of possibility, but must fall by 38k per day by Sept. Don't hold your breath. Good thing I called 2nd behind 2012 back in July, along with many others.
Title: Re: 2019 vs 2012
Post by: Killian on August 07, 2019, 04:51:02 PM
But by being mixed in with 7 other years, 2012 is only a partial influence.

But if something truly is anomalous, it should not be used to analyze norms, no?
Title: Re: 2019 vs 2012
Post by: dnem on August 07, 2019, 06:32:30 PM
I tend to think of the weather in each of past eight years (or whatever span) as having been drawn from some distribution of possible weather years.  The conditions that prevailed in 2012 got drawn from the distribution that year, and they'll come up again in the future.  And the odds of a "super melt" year will only increase in the future.  I think it would be foolish to remove 2012 from the average. 
Title: Re: 2019 vs 2012
Post by: gerontocrat on August 07, 2019, 06:59:19 PM
But by being mixed in with 7 other years, 2012 is only a partial influence.

But if something truly is anomalous, it should not be used to analyze norms, no?
Not good to exclude a piece of data because in your opinion it is an anomaly.
But it is OK to exclude it if it is part of a generally accepted methodology.

e.g. The DMI often exclude the highest and lowest variation from the average from their graphs (e.g. Greenland SMB graphs).

So I tried that (result attached). i.e. sum the last 10 years, subtract  the max and min values and divide the result by eight. Simple projection of JAXA minimum comes in at 50 k km2 higher.
It's the same as just using just the last 5 years
_______________________________________________________
A Cautionary tale ( and I believe not a shaggy dog story) about anomalies.

The scientists using the satellite system measuring ozone levels in the atmosphere way back when decided, that as there was a lot of noise in the data, to get the analysis program to automatically ignore the raw data outside certain parameters.

Later, a scientist with a bee in his bonnet decided to check the raw data, and quickly published a letter ion a scientific journal saying - "There is a big hole in the ozone layer above Antarctica". He was roundly poo-hoohed and generally derided, scoffed at.

Eventually cooler heads prevailed, the data was analysed again, new data collected, and of course he was right. Panic stations.
Title: Re: 2019 vs 2012
Post by: Killian on August 08, 2019, 09:46:41 AM

But if something truly is anomalous, it should not be used to analyze norms, no?
Not good to exclude a piece of data because in your opinion it is an anomaly.

Everything about '12 is... IMO.

LOL...

However, if, as many of us expect, 2019 will come in as the new 2nd lowest, then keeping '12 in the stats gets the closest result to a sub-'16 number. If we're wrong and '19 ends up kissin' cousin to '07 and '16, then... keeping '12 is still more accurate. Ergo, I'll shut up now.

  8   4.53                          8   4.53   
  9   5.05                          9   5.05   
14   4.88                        10   4.62   
13   4.81                        11   4.27   
10   4.62                        12   3.18   
17   4.47                        13   4.81   
18   4.45                        14   4.88   
11   4.27                        15   4.26   
15   4.26                        16   4.02   
16   4.02                        17   4.47   
12   3.18                        18   4.45   
                                   -H/L                                    -H/L
5 yr             4.04          4.18        5 yr          4.42      4.39
5 yr – 12      4.29               
4 yr – 12      4.25               

10 yr            4.40        4.47       10 yr           4.40     4.47
  9 yr – 12    4.54                       9 yr – 12   4.54   
10 yr – 12     4.54                    10 yr – 12    4.54   
Title: Re: 2019 vs 2012
Post by: Killian on August 08, 2019, 11:39:46 AM
Correct analysis, wrong number.

History repeats.

Again: Called -90k+/-10k. and got -107k to 5.42M. Lower than the previous day, not as low as I expected. Momentum really does seem to be the thing here. But, then, why the low days just a few days ago? That seems to have been mostly winds, so... ASI... argh...

--------------------------------------

Daily Change to Exceed 2012 Record Daily Lows

Quote
8/07/2012 = 5.38M km sq.
8/06/2019 = Stands at 5.51M. Loss of > 130k km sq.... to set record.

So 2012 leads by @ -40k. 24 hours later it'll be more like -140k, then 200k, then... Oh, my.

8/08/2012 = 5.19M km sq. after a huge 190k km sq fall.
8/07/2019 = Stands at 5.42M. Loss of > 230k km sq. needed to set a daily record for this date.

Analysis:
Little point in an analysis given that gap. It simply will not, cannot, happen. But, then, that's not really the point of this, is it? Nope. Let's try to get as close as we can to a correct number for the 8th, shall we?

Everything looks very much like today, just weaker winds and more surface heat further north, so I'll go with...

8/08/2019 = -90k+/-10km sq or 5.33M km sq.

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 160k km sq. for a record low on this post-GAC date. (3 days.)

This really has become absurd. Might be some strong melt in a couple days, but 2012 lost a LOT of ice over the same time period.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 57.44k km sq. for a record Sept. low. (40 days)

Even if the average keeps dropping at 1k/day, it ends up nowhere near 20k/day by Sept. 1. However, there is some serious warmth coming in over the Laptev Sea, noted by subgeometer on the 2019 melt season thread, that will likely do some damage to the Siberian side of the CAB, maybe deep into the center. The next 3 or 4 days might tell us quite a lot.
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 08, 2019, 02:59:21 PM
There are tests you can perform to detect outliers. Usually I leave them in my datasets because a reviewer may very well shit on you for asserting something is an outlier and basically send you back to the bench.

Any statistician will tell you that they have a strong distaste for outlier tests and I am inclined to agree, especially when that dataset is changing over time anyway- such as is the case for ASI.
Title: Re: 2019 vs 2012
Post by: dnem on August 08, 2019, 03:52:04 PM
Well sure, Simon. You can't just throw out a data point.  But we're talking about 7 years of weather here.  Hardly a robust data set from which you can make much of a prediction.  Plus, as you say, the baseline is shifting every year.  Obviously we need to consider the big melt years and the slow (rebound?) years as we think about what's to some.  But make a statistically valid prediction based on the weather since 2007, or 2011 or whatever recent year? Nah.
Title: Re: 2019 vs 2012
Post by: petm on August 08, 2019, 03:58:40 PM
A Cautionary tale ( and I believe not a shaggy dog story) about anomalies.

The scientists using the satellite system measuring ozone levels in the atmosphere way back when decided, that as there was a lot of noise in the data, to get the analysis program to automatically ignore the raw data outside certain parameters.

Later, a scientist with a bee in his bonnet decided to check the raw data, and quickly published a letter ion a scientific journal saying - "There is a big hole in the ozone layer above Antarctica". He was roundly poo-hoohed and generally derided, scoffed at.

Eventually cooler heads prevailed, the data was analysed again, new data collected, and of course he was right. Panic stations.

Indeed. From what I understand, it wasn't until after British Antarctic Survey scientists published a Nature paper about the hole in 1985 that the Americans (NASA) took their satellite data at face value.
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 08, 2019, 04:13:48 PM
Well sure, Simon. You can't just throw out a data point.  But we're talking about 7 years of weather here.  Hardly a robust data set from which you can make much of a prediction.  Plus, as you say, the baseline is shifting every year.  Obviously we need to consider the big melt years and the slow (rebound?) years as we think about what's to some.  But make a statistically valid prediction based on the weather since 2007, or 2011 or whatever recent year? Nah.

Hence why year on year the ASIF members June predictions of the September-minima are invariably negatively skewed!

Its my personal belief that a state-change occurred around 2000 and that fitting any kind of regression from 1979 is not valid any more. Nor is comparing pre-2000s el-ninos with post-2000s el ninos.
Title: Re: 2019 vs 2012
Post by: Klondike Kat on August 08, 2019, 05:14:41 PM
Well sure, Simon. You can't just throw out a data point.  But we're talking about 7 years of weather here.  Hardly a robust data set from which you can make much of a prediction.  Plus, as you say, the baseline is shifting every year.  Obviously we need to consider the big melt years and the slow (rebound?) years as we think about what's to some.  But make a statistically valid prediction based on the weather since 2007, or 2011 or whatever recent year? Nah.

Hence why year on year the ASIF members June predictions of the September-minima are invariably negatively skewed!

Its my personal belief that a state-change occurred around 2000 and that fitting any kind of regression from 1979 is not valid any more. Nor is comparing pre-2000s el-ninos with post-2000s el ninos.

It may have been a state change, or it may just be that the peripheral ice has all melted, and the core remains.  The core will be more difficult to melt, hence the slowdown.  Then again, maybe there was some systematic change in the oceans.  Whatever the reason, there has been a change.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 04:40:02 AM
But we're talking about 7 years of weather here.  Hardly a robust data set from which you can make much of a prediction.

You mean 7 years of data isn't enough to predict weather? That would b a wild assertion given the short-term nature of weather forecasting. I'm assuming you mean seven years of weather is not enough to forecast climate?

Either way, this would be incorrect. First, in any given year, the majore forcing for the ASI minima is weather, but overall the climatic changes are setting the context. I would suggest that climate forcing is changing so fast and at such magnitude, it is having noticeable yearly effects. Still, most of the year-to-year differences will be weather. Climate is found in the trends.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 05:19:26 AM
Well sure, Simon. You can't just throw out a data point.  But we're talking about 7 years of weather here.  Hardly a robust data set from which you can make much of a prediction.  Plus, as you say, the baseline is shifting every year.  Obviously we need to consider the big melt years and the slow (rebound?) years as we think about what's to some.  But make a statistically valid prediction based on the weather since 2007, or 2011 or whatever recent year? Nah.

Hence why year on year the ASIF members June predictions of the September-minima are invariably negatively skewed!

Its my personal belief that a state-change occurred around 2000 and that fitting any kind of regression from 1979 is not valid any more. Nor is comparing pre-2000s el-ninos with post-2000s el ninos.

It may have been a state change, or it may just be that the peripheral ice has all melted, and the core remains.  The core will be more difficult to melt, hence the slowdown.  Then again, maybe there was some systematic change in the oceans.  Whatever the reason, there has been a change.

Simon can dismiss what he likes, but I suggest he's making logical errors in doing so. Claiming 1. there was a phase change in 2000 and 2. ignoring the biggest EN happened in '98 is not a tenable position. The EN's bring water energy to the surface. It does not suck it back in the way it rapidly ejects it. It's essentially a tide raiser for climate change.

It is no accident the lows of '05, '07, '10, '11 '12 and '16 are all associated with EN's. Not only do the EN's pump energy into the atmosphere in general, affecting *global* weather, but they must send energy into the Arctic, also. The ENs are a Pacific phenomenon and it is Pacific waters flowing into Chukchi and feeding the Transpolar current across Siberia. Is it any accident the Siberian coast has the least ice when it is fed by the Pacific inflow? The Beaufort is also clearly effected by this as the gyre sucks water around into the Beaufort.

Note, also, there were a lot of ENs in the 2000's and the range of minima was huge, 3M km, while the 2010's range has fewer ENs and a range of 1.8M or so. Take out 2012 and it's less than 1M. Let's go back to the potential outlier. I had forgotten 2010 *and* 2011 were record years. No wonder we thought 2012 was the end of the ice! We'd seen a mild (in retrospect) new low in 2005, a bigger one in 2007, then '10 and '11 came along, and the differential was quite large: @ 350k km sq between '10 and '11.

In this context, we must see the preceding lows as preconditioning for 2012 which made the very unusual weather patterns for 2012 particularly impactful. All those EN's pumped a lot of energy into the global system.

Also, there is absolutely nothing that says ENs function differently pre- and post-2000, so no rationale for treating them differently.
Title: Re: 2019 vs 2012
Post by: Michael Hauber on August 09, 2019, 05:58:48 AM

It is no accident the lows of '05, '07, '10, '11 '12 and '16 are all associated with EN's.

Nino 3.4 index for September for the above years:

2005 -0.08
2007 -1.04
2010 -1.56
2011 -0.76
2012 +0.44
2016 -0.46

Warmest nino 3.4 index for 12 months prior to September for the above years:

2005 +0.71
2007 +1.1
2010 +1.81
2011 -0.23
2012 +0.44
2016 +2.57

None of those minimums occurred during el nino events.  Four of those six minimums occurred within 12 months after an el nino event, which is only one more than half.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 06:05:08 AM
Daily Change to Exceed 2012 Record Daily Lows
8/08/2012 = 5.19M km sq. after a huge 190k km sq fall.
8/07/2019 = Stands at 5.42M. Loss of > 230k km sq. needed to set a daily record for this date.

8/08/2019 = -90k+/-10km sq or 5.33M km sq.

On the nose. Good. Whew...

8/09/2012 = 5.04M km sq. after a large 150k km sq fall.
8/08/2019 = Stands at 5.33M. Loss of > 290k km sq. needed to set a daily record for this date.

Winds shift more to favorable for compaction except along the Svalbard, et al., archipelago, where export should be stronger, but similar to the previous day. That should be balanced by more heat energy flowing in from the Beaufort around to the Laptev and more favorable winds for compaction there, generally, too. I'm tempted to call 90k again bc of the export/expansion, but the winds and heat should eat up some of that remaining whispy stuff. Losing ice in the CAA, too.

Call it 105k+/-10k.

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 160k km sq. for a record low on this post-GAC date. (2 days.)

Let the absurdity roll: -190k/day with 2 days to go.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 56.38k km sq. for a record Sept. low. (38 days)

Steady drops, bad weather maybe on the way according to the folks who keep tabs on the long-range forecasts. The ice looks like poop. Lots of ice going bye-bye in the CAA. Still at record low PIOMAS volume.

Could still be interesting.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 06:06:54 AM

It is no accident the lows of '05, '07, '10, '11 '12 and '16 are all associated with EN's.

Nino 3.4 index for September for the above years:

2005 -0.08
2007 -1.04
2010 -1.56
2011 -0.76
2012 +0.44
2016 -0.46

Warmest nino 3.4 index for 12 months prior to September for the above years:

2005 +0.71
2007 +1.1
2010 +1.81
2011 -0.23
2012 +0.44
2016 +2.57

None of those minimums occurred during el nino events.  Four of those six minimums occurred within 12 months after an el nino event, which is only one more than half.

Why are you commenting if you don't understand the theory?
Title: Re: 2019 vs 2012
Post by: Michael Hauber on August 09, 2019, 06:11:34 AM


Why are you commenting if you don't understand the theory?

I know enough about ENSO to correctly identify which years were el nino influenced and which were not.
Title: Re: 2019 vs 2012
Post by: binntho on August 09, 2019, 07:58:29 AM


Why are you commenting if you don't understand the theory?

I know enough about ENSO to correctly identify which years were el nino influenced and which were not.
Yes, it's a bit weird continuing to claim things that do not verify. If you have a theory that you are working from, how about some explanations and then we can see if the theory holds by comparing it to actual data.

<snip>
It is no accident the lows of '05, '07, '10, '11 '12 and '16 are all associated with EN's
</snip>

Associated how?

'05 was preceded by three years with positive ENSO index, including two minor EN
'07 preceded by five years positive ENSO index,  three minor EN and one minor LN
'10 was not a low - one year positive ENSO, 2 years negative. Since '07 two LN and one EN
'11 was not a low - preceded by one year negative, 1 positive, 2 negative, three LN and one EN
'12 preceded by 2 negative, 1 positive, 2 negative.
'16 in the middle of a massive EN, including previous year, preceded by a decade of negative ENSO index (with the exception of 2009)

I'm not seeing any rythm here.

Quote
Not only do the EN's pump energy into the atmosphere in general, affecting *global* weather, but they must send energy into the Arctic, also.
Must they? Well, yes, of course, as a part of their general contribution to global warming. But not as a discernible direct causal effect. Or are we missing something? What?
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 09, 2019, 11:06:28 AM
Killian, if you feel so strongly about it and so readily rebut other's opinions  (which is fair enough), why not collate your data and submit it as a paper? Cryology is clearly lacking a cohesive and strong argument either way- why not contribute?

Submit it for a peer review and see what comes back.
Title: Re: 2019 vs 2012
Post by: oren on August 09, 2019, 12:16:30 PM
Killian - I believe you are making a wrong statement about the relationship of EN and sea ice minima, not supported by the data, as so many above have already rebutted. However, as you are intent on your claim, and assuming submitting a peer-reviewed paper is not your thing, why not at least start a new thread (or dig up an existing one) dealing specifically with the effect of ENSO on sea ice? This thread here was started by Neven specifically to compare 2012 and 2019, and should not be derailed by a side scientific discussion, as interesting as it might be.
Title: Re: 2019 vs 2012
Post by: Archimid on August 09, 2019, 12:41:27 PM
My reply To ENSO/ASI discussion here:

https://forum.arctic-sea-ice.net/index.php/topic,405.0.html

I invite you to continue this, IMHO, highly relevant discussion there. If you have a better thread let me know.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 02:25:03 PM
Killian, if you feel so strongly about it and so readily rebut other's opinions  (which is fair enough), why not collate your data and submit it as a paper? Cryology is clearly lacking a cohesive and strong argument either way- why not contribute?

Submit it for a peer review and see what comes back.

Not my job. Not a scientist. I bring things to people's attention. Let them that do that sort of thing do so. Not being flippant; I do not have the chops to do a scientific paper on this. I'm a systems, patterns, meta thinker, not a data, fine details sort. One half of a great team, maybe, but not both halves on my own.

Others,

The issue WRT EN has evolved re it's relevance here. My theory, in specific, need not be gone over any further on this thread. I would ask that people who this interests pay attention to the *seeming* correlation of ENs, their "goosing" of the global system (and the more disturbed a systm becomes the more sensitive to changes, so maybe that's why we've seen a potential change in impacts post-2000 (1998 in my book)?) and longer-term effects on sea ice.

BTW, it's not about directly melting ice, per se, so much as it's about energy broadly distributed and preconditioning.

I'll try to find the two papers on Pacific heat and moisture affecting sea ice that would seem to lend peripheral support to this concept.

What still most interests me re 2012 vs 2019 is the anomalous aspects of 2012 and the fact 2019 has had none like 2012, but has 1 or two of it's own.

Specifically, the two periods of very high, short-term extent loss from June 6th to the 13th or so and the period of the GAC in 2012. The latter has been beaten pretty wellm though I think a somewhat more nuanced discussion might be had there tha would bring everyone to agreement. The June event needs some discussion.

I finally, after wallowing around trying to figure out how to get info on the conditions for that second week in June (because literally not one person ever responded about it in any way, shape, or form), just went to Worldview and looked. Et viola! VERY sunny skies just during that period. We all learned only recently about a strong correlation between June insolation and Sept. minima. Well, there's your smoking gun. While June 2019 blew the doors off, there was a solid 8 days in early June 2012 with almost all sun... and a 930k km sq, iirc, drop.

If you use JAXA's interactive ASIE graph and pull up only 2019 and 2012... or 2012 and any other years, you can see those two weeks very clearly.

Cheers
Title: Re: 2019 vs 2012
Post by: binntho on August 09, 2019, 02:36:08 PM
The issue WRT EN has evolved re it's relevance here. My theory, in specific, need not be gone over any further on this thread. I would ask that people who this interests pay attention to the *seeming* correlation of ENs, their "goosing" of the global system (and the more disturbed a systm becomes the more sensitive to changes, so maybe that's why we've seen a potential change in impacts post-2000 (1998 in my book)?) and longer-term effects on sea ice.

Well I think this was OT from the start, EN has no bearing on any comparison between 2012 and 2019 given how radically different the ENSO index has been in the lead up to those two years, e.g.  2008-2012 (0.1) and 2015-2019 (0.9)

So a bit more OT: Your theory, "in specific", has not been gone over at all on this thread. There is no "seeming" correlation of ENs, and what in earth does "goosing" have to do with this? Will we be "gandering" soon as well?
Title: Re: 2019 vs 2012
Post by: AndyW on August 09, 2019, 03:23:51 PM

We can dumb down the 2019 v 2012 argument simply to Occams razer, and that is that so far there in 2019 there has not been any severe  weather so far that could create enough of a change either way, up or down, to provide an outlier as 2007 and 2012 had.

2007 had an anomalously large number of sunny days coupled with a warm southerly wind from the Russian side,  2012 had warm conditions plus cyclonic wind that provided dispersion and melting.

It would be best to actually ignore these two outliers completely and instead concentrate on the other years in the last 15 years to compare 2019 to.


Andy
Title: Re: 2019 vs 2012
Post by: Aluminium on August 09, 2019, 04:16:41 PM
It becomes more and more interesting.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 06:01:24 PM
The issue WRT EN has evolved re it's relevance here. My theory, in specific, need not be gone over any further on this thread. I would ask that people who this interests pay attention to the *seeming* correlation of ENs, their "goosing" of the global system (and the more disturbed a systm becomes the more sensitive to changes, so maybe that's why we've seen a potential change in impacts post-2000 (1998 in my book)?) and longer-term effects on sea ice.

Well I think this was OT from the start, EN has no bearing on any comparison between 2012 and 2019 given how radically different the ENSO index has been in the lead up to those two years, e.g.  2008-2012 (0.1) and 2015-2019 (0.9)

So a bit more OT: Your theory, "in specific", has not been gone over at all on this thread. There is no "seeming" correlation of ENs, and what in earth does "goosing" have to do with this? Will we be "gandering" soon as well?

I'm not going to go over the entire history of it all to deal with your lack of insight or awareness. You don't see, so it doesn't exist. Got it. God, thank you.

Now, not-God, Since I had clearly stated I wasn't going to discuss it anymore, your post is a perfect example of trolling/blowing on the embers. It was let lie, but you could not.

Get you ego and your arrogance out of the equation, please, and pay attention to what people say. I said I was happy to let it go. Suggest you do, too, particularly when you have exactly zero to add to the conversation other than, "Uh-uh!"

Criminy....
Title: Re: 2019 vs 2012
Post by: binntho on August 09, 2019, 06:24:13 PM
Temper, Killian. I wasn't the one filling the thread with OT unsupported claims that were simply wrong as has been repeatedly shown.

I did suggest several times to move this over into another thread, but no, you apparently felt your claims were too important. Yet somehow very difficult to substantiate.

Anyway, I'm happy to leave this subject, since it's clearly been battered out of existence by lack of evidence.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 07:07:13 PM
Temper, Killian. I wasn't the one filling the thread with OT unsupported claims that were simply wrong as has been repeatedly shown.

I did suggest several times to move this over into another thread, but no, you apparently felt your claims were too important. Yet somehow very difficult to substantiate.

Anyway, I'm happy to leave this subject, since it's clearly been battered out of existence by lack of evidence.

Seriously, get over yourself. Stop posting comments that serve nothing but your ego.

Someone said there is a way to mute people... I don't like jerks.
Title: Re: 2019 vs 2012
Post by: Killian on August 09, 2019, 07:10:52 PM


Why are you commenting if you don't understand the theory?

I know enough about ENSO to correctly identify which years were el nino influenced and which were not.

It is not your theory, thus you are completely incorrect. I stated clearly you must look at a two-year period, you responded discussing only a one-year period making your response irrelevant.

And your statement is an opinion which you state as fact, so doubly incorrect.
Title: Re: 2019 vs 2012
Post by: Sterks on August 09, 2019, 07:33:23 PM


Why are you commenting if you don't understand the theory?

I know enough about ENSO to correctly identify which years were el nino influenced and which were not.

It is not your theory, thus you are completely incorrect. I stated clearly you must look at a two-year period, you responded discussing only a one-year period making your response irrelevant.

And your statement is an opinion which you state as fact, so doubly incorrect.

Of couse Niños elevate the tide of AGW and I agree some direct impact can be observed (such as 2016 a year with no June sun, a stormy July and a GACCY August, where shear warmth of the NH post Niño was also noticeable pulling a Nr 2 in area). I can also understand for the same reason 2000 low post 98.

But the rest is weak stuff. It’s there, it affects sea icesomehow, but the numerology you manage I don’t follow. Anyway, if you look at a period of two years, the probability of catching a Niño is pretty high.
Drop it here anyway.
Title: Re: 2019 vs 2012
Post by: binntho on August 10, 2019, 07:00:21 AM
Someone said there is a way to mute people... I don't like jerks.
Go to Profile, Modify Profile, Buddies/Ignore List, Edit Ignore List. It's not easy to find! I've only ever ignored one poster, and I certainly won't ignore you Killian but feel free to ignore me whenever you feel like it!
Title: Re: 2019 vs 2012
Post by: Killian on August 10, 2019, 10:22:24 AM
8/09/2012 = 5.04M km sq. after a large 150k km sq fall.
8/08/2019 = Stands at 5.33M. Loss of > 290k km sq. needed to set a daily record for this date.

...Call it 105k+/-10k.

And we ended up with... 5.239 or a drop of 95k. Nice. Within range. But, that's the 3rd time I didn't go with my gut and ended up wider of the mark than I would have. Ah... trusting your intuition is a hard thing to learn to do. 

8/10/2012 = 4.94M km sq. after a 100k drop, the last of the GAC -100+ days.
8/09/2019 = Stands at 5.24M. Loss of > 300k km sq. needed to set a daily record for this date.

Call it 95k+/-10k.

Analysis: The loose ice in the Beaufort gyre just doesn't move much of late. I suspect this is due to the winds being opposite of the gyre currents, so call that a draw. From the mid-Alaskan shore to the Strait it's one side of a cyclone and from there further into the Chukchi it's the other side of the cyclone. Call it a draw. Winds comeing off of Siberia over the western half of the ESS and over the Laptev are toward the ice pack, and stronger than some recent days. Winds headed out over Svalbard into the Barents are going to be strong, but the ice there doesn't repsond much to winds, either. At least not recently. And over the Kara they'll be toward the CAB.

So... more momentum and with higher winds over the most mobile ice off of parts of Siberia, we get a nice little sub-100k day of ASIE, noted above. Could be a pretty low day, so don't be surprised if I'm high by quite a bit, particularly if the Atlantic side gets into motion.

The 11th looks really interesting...

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

8/10/2012 stood at 4.94M km sq.
2019 needs a drop of > 299k km sq. for a record low on this post-GAC date. Final day! Thank the gods!  This number does tell us something of interest, however, if we bring 2016 into the picture. The magnitude of 2019 so far is clear when we consider '19 is +200 to 2012, but -420 to '16. So far, as if we didn't know, '19 really is unusual because it has been so normal. The only outstanding element so far is the sheer amount of heat in the system; two straight all-time hottest months and a June with record insolation, I believe, and the scientific finding that June insolation correlates well with Sept. minima.

That heat's not an Arctic phenomenon, it's very much a global one. But imagine if the huge outlier that is 2012 had never happened and 2019 came along? We'd be treating it like the end of all ice, like some thought back in '12.

I believe 2016 pumped so much energy out of the oceans and to the surface that it initiated/pushed a number of feedbacks into gear/higher gear. For '17 and '18 I think maybe this exhibited in the Arctic primarily as low winter ASI accumulation.

415ppm, folks, is looking deadly.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 55.65k km sq. for a record Sept. low. (37 days)
Title: Re: 2019 vs 2012
Post by: binntho on August 10, 2019, 10:32:11 AM
<snip>
But imagine if the huge outlier that is 2012 had never happened and 2019 came along? We'd be treating it like the end of all ice, like some thought back in '12.
</snip>

So true!
Title: Re: 2019 vs 2012
Post by: SimonF92 on August 10, 2019, 01:03:52 PM
2012 has the advantage peripherally, 2019 has the advantage toward the core
Title: Re: 2019 vs 2012
Post by: Random_Weather on August 10, 2019, 01:29:48 PM
For some Folks not uninteresting

(https://s18.directupload.net/images/190810/mxy4yw38.png) (https://www.directupload.net)
Data: ftp://ftp.remss.com/sst/daily/mw_ir/v05.0/netcdf/ (need for registry)
Red: 2019 warmer
Blue: 2019 cooler

(https://s18.directupload.net/images/190810/z7kb2uav.png) (https://www.directupload.net)
https://seaice.uni-bremen.de/data/amsr2/asi_daygrid_swath/n6250/netcdf/

Red: 2019 more SIC
Blue: 2019 less SIC
Title: Re: 2019 vs 2012
Post by: binntho on August 10, 2019, 01:33:27 PM
For some Folks not uninteresting

For me very interesting!
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 10, 2019, 07:59:49 PM
Thanks Random, very interesting views
Title: Re: 2019 vs 2012
Post by: D-Penguin on August 10, 2019, 08:46:53 PM
QUOTE from Killian on: Today at 10:22:24 AM
"9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 55.65k km sq. for a record Sept. low. (37 days)"

If the date of minimum extent for 2019 is extended by 8 days compared to 2012 because of the additional heat energy in the Arctic system:-

2019 would need an average daily drop of > 45.76k km sq. for a record September low (45 days)

Presumably the soot deposits from current forest fires in the Arctic region will increase to some degree top melting during the period of diminishing insolation until the September equinox adding to side and bottom melt.

Whatever the outcome of the present melting season, the onset of the 2019/20 re-freezing season will be very interesting.
Title: Re: 2019 vs 2012
Post by: Neven on August 10, 2019, 10:03:59 PM
For some Folks not uninteresting

Very nice, RW! I wish I knew how to do that kind of stuff.
Title: Re: 2019 vs 2012
Post by: Random_Weather on August 11, 2019, 06:51:58 AM
Neven,

Thats very easy, you just need to download: https://www.giss.nasa.gov/tools/panoply/

I wonder that most people here dont know about?
Title: Re: 2019 vs 2012
Post by: DrTskoul on August 11, 2019, 07:07:33 AM
Actually first mentioned in 2013: https://forum.arctic-sea-ice.net/index.php/topic,384.msg16282.html#msg16282 version 3.

I guess after a while these useful links get buried/forgotten
Title: Re: 2019 vs 2012
Post by: Killian on August 11, 2019, 07:10:43 AM
QUOTE from Killian on: Today at 10:22:24 AM
"9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 55.65k km sq. for a record Sept. low. (37 days)"

If the date of minimum extent for 2019 is extended by 8 days compared to 2012 because of the additional heat energy in the Arctic system:-

2019 would need an average daily drop of > 45.76k km sq. for a record September low (45 days)

No way to know how long the melt season will go, of course. I base that number on the first day JAXA reaches 3.18 bc the comparison is with the 2012 low, but the next day is likely a few k km lower, though also 3.18 on their chart. Anything from the 15th to 17th would likely be ok. And, sure, if it goes on another week or two, that changes things quite a bit.

Note, however, that bc most of the melt happens before Sept, the daily average needs to be about 20k per day remaining by Sept. 1 to be close to a new record.
Title: Re: 2019 vs 2012
Post by: Killian on August 11, 2019, 07:13:33 AM
2012 has the advantage peripherally, 2019 has the advantage toward the core

Suggests higher chance of record low area/volume than extent, maybe?
Title: Re: 2019 vs 2012
Post by: Killian on August 11, 2019, 07:50:50 AM
8/10/2012 = 4.94M km sq. after a 100k drop, the last of the GAC -100+ days.
8/09/2019 = Stands at 5.24M. Loss of > 300k km sq. needed to set a daily record for this date.

Call it 95k+/-10k.

Or not. -130k. 25k beyond my range ain't bad, is it? LOL...

Quote
The 11th looks really interesting...

At least that is still true...

8/11/2012 = 4.89M km sq. after a 50k drop. Exhausted after the GAC, I guess.
8/10/2019 = Stands at 5.11M. Loss of > 220k km sq. needed to set a daily record for this date.

2019's 130k drop helped tighten things up a bit. Another 100k+ day would go a long way towards making this look like a horse race again.

Analysis:

There are so many cyclonic forces going on right now, it's impossible to sort out what in the world is going to happen. To make it even more ambiguous, despite all the cyclones/anti-cyclones, most of the wind direction at the surface is going *across* the ice edges for the most part for most of the 11th - according to NullSchool. What in the world does wind across the ice edge do, tickle it to death? The exception for the day seems to be the area of the Fram Strait and Svalbard, so we may get some export. I don't think that will affect etent much.

The one thing that might keep the loss over 100k is the surface heat, though not esceptionally high, is over a very large area, with, as others have noted, particular incursion over the Laptev where there isn't much ice near shore, but a lot of mushy stuff. Coming with the winds and heat is... soot. Holy melt, Batman, if that stuff gets onto the ice! Of course, if it stays up in the air it will block sunlight and maybe cool the area it's over.

Let's go with momentum and heat: 110k+/-10k.

Zero confidence in this prediction.

-------------------------------

Daily Changes Needed to Exceed 2012 low on Aug. 10.
(Related to effect of GAC and it's import vs. 2019's melt cycle.)

Quote
8/10/2012 stood at 4.94M km sq.
2019 needs a drop of > 299k km sq. for a record low on this post-GAC date. Final day!

Ding-dong the GAC is dead, the GAC is dead, the GAC is dead!

Got a -130k drop and ended up 170k higher. I said a good while back if 2019 was below or near 2012 on this date there'd be a good chance of a new record. 170k higher adds a bit less than 5k to the daily average melt needed. Not small, but within reach.

Anywho... that's the end of this run.

Daily Changes Needed to Exceed 2012 Record Low on Sept. 15.
(Related to comparison of 2012 vs 2019's melt cycle.)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 53.61k km sq. for a record Sept. low. (36 days)

For perspective, on Sept. 1 the average melt needed to the 15th is about 20k. 2019 needs to eat up 23.61k/day over the next 21 days. Well, hell, if Sept can chew up the equivalent of 20k/day for 15 days, August can chew up 23 or 24 per day over 21.

I think we have ourselves a horse race.
Title: Re: 2019 vs 2012
Post by: Killian on August 11, 2019, 07:53:32 AM
Anyway, if you look at a period of two years, the probability of catching a Niño is pretty high.
Drop it here anyway.

As I've mentioned, and so needs to be checked.
Title: Re: 2019 vs 2012
Post by: D-Penguin on August 11, 2019, 12:57:56 PM
8 or 10 days added to the average minimum date could be the deciding factor as to whether or not 2019 produces a new record minimum.

If 2018/19 and 2020 show progressive extensions of the minimum date, 20-20 vision is not required to see what happens next! SSTs and advection regardless of solar insolation in the Arctic.

What happens in the Arctic does not stay in the Arctic.
More importantly:-
What happens outside the Arctic does not stay outside the Arctic!!!
Title: Re: 2019 vs 2012
Post by: AndyW on August 11, 2019, 07:34:01 PM
The interesting feature at the moment is that the tongue of ice into the east siberian sea, which had older ice due to failure to melt last few years,  has now almost melted out it seems.

Big loses extent wise always favourable to the Russian side.   



Title: Re: 2019 vs 2012
Post by: uniquorn on August 11, 2019, 10:51:00 PM
Not sure it this is helpful but here attempting to overlay unihamburg amsr2-uhh 2012 onto 2019, aug1-10.
2012 lower ice concentration has been colorised purple and is overlayed at 60% transparent to allow 2019 ice edge to show through. 2012 0% concentration (usually dark blue) has been set to fully transparent.
7days/sec is quite fast but helps to identify which year is which.

Concentration shouldn't be seen as meaningful as 2012 has been enhanced somewhat to bring out the ice edge and the overlay of white on white distorts concentration nearer the pole.
tech note: edge detect was too messy in this case
Title: Re: 2019 vs 2012
Post by: Sterks on August 11, 2019, 11:09:57 PM
Not sure it this is helpful but here attempting to overlay unihamburg amsr2-uhh 2012 onto 2019, aug1-10.
2012 lower ice concentration has been colorised purple and is overlayed at 60% transparent to allow 2019 ice edge to show through. 2012 0% concentration (usually dark blue) has been set to fully transparent.
7days/sec is quite fast but helps to identify which year is which.

Concentration shouldn't be seen as meaningful as 2012 has been enhanced somewhat to bring out the ice edge and the overlay of white on white distorts concentration nearer the pole.
tech note: edge detect was too messy in this case
This week, while the pacific edge was being severely affected by the GAC in 2012, it has been an immobile and relatively cold week for this edge in 2019. Extent has continued dropping but note that 2012 started higher in extent.
Next week is the one where 2019 won’t really follow the pace, although it will follow a vigorous pace for the time of the year given the weather.
Title: Re: 2019 vs 2012
Post by: TeaPotty on August 11, 2019, 11:29:32 PM
Not sure it this is helpful but here attempting to overlay unihamburg amsr2-uhh 2012 onto 2019, aug1-10.
2012 lower ice concentration has been colorised purple and is overlayed at 60% transparent to allow 2019 ice edge to show through. 2012 0% concentration (usually dark blue) has been set to fully transparent.
7days/sec is quite fast but helps to identify which year is which.

Concentration shouldn't be seen as meaningful as 2012 has been enhanced somewhat to bring out the ice edge and the overlay of white on white distorts concentration nearer the pole.
tech note: edge detect was too messy in this case
This week, while the pacific edge was being severely affected by the GAC in 2012, it has been an immobile and relatively cold week for this edge in 2019. Extent has continued dropping but note that 2012 started higher in extent.
Next week is the one where 2019 won’t really follow the pace, although it will follow a vigorous pace for the time of the year given the weather.

Sterks is on a mission!
Even as 2019 and 2012 remain tightly competitive, lol 😂
Title: Re: 2019 vs 2012
Post by: Sterks on August 11, 2019, 11:44:55 PM
Not sure it this is helpful but here attempting to overlay unihamburg amsr2-uhh 2012 onto 2019, aug1-10.
2012 lower ice concentration has been colorised purple and is overlayed at 60% transparent to allow 2019 ice edge to show through. 2012 0% concentration (usually dark blue) has been set to fully transparent.
7days/sec is quite fast but helps to identify which year is which.

Concentration shouldn't be seen as meaningful as 2012 has been enhanced somewhat to bring out the ice edge and the overlay of white on white distorts concentration nearer the pole.
tech note: edge detect was too messy in this case
This week, while the pacific edge was being severely affected by the GAC in 2012, it has been an immobile and relatively cold week for this edge in 2019. Extent has continued dropping but note that 2012 started higher in extent.
Next week is the one where 2019 won’t really follow the pace, although it will follow a vigorous pace for the time of the year given the weather.

Sterks is on a mission!
Even as 2019 and 2012 remain tightly competitive, lol 😂

Yeah, whatever. Go back to lurking if you don't really have anything to positively contribute with.
Title: Re: 2019 vs 2012
Post by: uniquorn on August 12, 2019, 01:18:16 AM
This week, while the pacific edge was being severely affected by the GAC in 2012, it has been an immobile and relatively cold week for this edge in 2019. Extent has continued dropping but note that 2012 started higher in extent.
Next week is the one where 2019 won’t really follow the pace, although it will follow a vigorous pace for the time of the year given the weather.
As a relative newcomer to the forum, with 2012's reputation, it's amazing to see how much ice is left in the chukchi.
Title: Re: 2019 vs 2012
Post by: HapHazard on August 12, 2019, 08:11:51 AM
Looking at the most recent extent graphs in the data thread, using a cycling analogy: It kinda looks like the 2012 GAC amounts to a breakaway while 2019 is the peloton, going steady. Will 2019 chase it down? Did 2012 break too early & lose steam? Very interesting!

Here's my graphical scientific representation of 1 potential outcome (exaggerated for clarity):

Title: Re: 2019 vs 2012
Post by: BenB on August 12, 2019, 09:41:34 AM
SST update for 11 August 2012 vs 2019. The next few days will see warm, humid air and warm waters push north into the Laptev sector of the CAB. Meanwhile, northerlies will transport/export ice into the Chukchi, on one side of the Arctic, and into the Barents/Greenland seas on the other. I would expect area declines to pick up, but extent may hold up better initially. We could also see more areas of open water near the Pole as the ice is pushed apart.
Title: Re: 2019 vs 2012
Post by: peterlvmeng on August 12, 2019, 09:51:33 AM
SST update for 11 August 2012 vs 2019. The next few days will see warm, humid air and warm waters push north into the Laptev sector of the CAB. Meanwhile, northerlies will transport/export ice into the Chukchi, on one side of the Arctic, and into the Barents/Greenland seas on the other. I would expect area declines to pick up, but extent may hold up better initially. We could also see more areas of open water near the Pole as the ice is pushed apart.

Good comparison!
Title: Re: 2019 vs 2012
Post by: philopek on August 12, 2019, 06:40:40 PM
Looking at the most recent extent graphs in the data thread, using a cycling analogy: It kinda looks like the 2012 GAC amounts to a breakaway while 2019 is the peloton, going steady. Will 2019 chase it down? Did 2012 break too early & lose steam? Very interesting!

Here's my graphical scientific representation of 1 potential outcome (exaggerated for clarity):

This was what one of the guests posted back in spring and I think the steady decline in 2019 could indeed be key feature of this season.

Also in contrast to other opinions i think there is a lot of dispersed ice left to melt and the easy ice is not gone yet by far.

Weather, as it always has been, will define the outcome when it comes to 1st or 2nd while I think that for a 3rd place an extreme weather on the ice-friendly side would be needed and that's simply not in sight yet and in 2 weeks we are gonna see the 2016 low valu if things continue just a little longer like they do now.
Title: Re: 2019 vs 2012
Post by: Sterks on August 12, 2019, 07:00:26 PM
Yes, there's a lot of ice to go, on the order of 1M km2 to maybe 1.5M km2. That is a lot.
But not 2M as in 2012.
Title: Re: 2019 vs 2012
Post by: petm on August 12, 2019, 07:13:33 PM
It says a lot that we're in the 2nd week of August and this is still a very open question, even without any major weather event (or at least no GAC).
Title: Re: 2019 vs 2012
Post by: JUST ICE on August 14, 2019, 12:19:06 AM
Has anyone given any consideration to the fact that 2012 was a leap year?. Because of the additional "leap day" we are, in essence, comparing 2019's todays with 2012's tomorrows. In the race to the bottom 2012 has been given a one day head start but it's just an illusion of our imperfect calendar.

I know NSIDC has considered this as their Chartic graph shows 2012 dats points (and those of all leap years) offset by one day. After leap day, that is.
Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 14, 2019, 07:20:43 AM
Post 1 of 2
     As per request I added an alternate version of the 2019 projected minimum based on extending the melt season to date anomaly vs. 2011-2018 average.  Thus if 2019 reduction in that measure to date was 5% higher than in 2011-2018, then the remaining projected losses to minimum would also be 5% higher instead of using the 2011-2018 average losses from latest observation date to annual minimum.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F2u7ymv4.gif&hash=98b6cc4a7f3bc62d9ef939286a08b32d)





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FWIW - August  12,  2019 has more ice on the Russian side which is surprising with the persistent high temperatures in coastal Siberia earlier this summer.  But 2019 has less ice in core of what used vto the MYI triangular fortress from norther Greenland  to North Pole and Down to Ellesmere Island.  Even though 2019 does not look to break the 2012 records for Extent and Area, it seems that the condition of the CAB is substantially weaker.  Also the high concentration/low spread CAB ice in 2019 is perched closer to the Fram Strait exit ramp.  I guess too late this year for it to get shuttled out of the Arctic and who knows where that ice will be next June.   But that location seems to be more bad news for ASI.



EDIT -- Dang - forgot to update 2019 projected min Extent and Areas based on 2011-2018 remaining losses in the tables.  Can't fix right now, away from computer.  Values in text section above tables are the correct ones.  The yellow shaded Extent in table should be 3.80 & 114%.  Yellow shaded AREA should 2.60 & 117%.
   Thus, since August 4 Extent got closer to 2012, but Area fell farther behind.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi68.tinypic.com%2F2h37n14.gif&hash=1aec97816e945e1bc64f3ace3d93d73a)
 

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Title: Re: 2019 vs 2012
Post by: Glen Koehler on August 14, 2019, 07:26:01 AM
Post 2 of 2
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F35lye8o.gif&hash=27ff9c09b699afa4745a8d8bc319d36e)

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The 2019 average index calculated by current melt season anomalies is marked with * and is shaded green.  The projected 2019 minimum Extent, Area, Volume, and Thickness values based on current melt season anomalies appear to less reliable predictors than the 2011-2018 average remaining losses.  The average ratio for based on the 2019 melt season anomaly estimates is included in the table to show relative position, but to avoid assigning two ordinal ranks to a single year, only the 2019 minimums based on 2011-2018 average remaining losses are assigned a rank vs. other years.  Likewise, the color coding for 1st, 2nd, etc. lowest values does not include the 2019 melt season anomaly values.

EDIT -- Dang part 2.  Away from computer and can,t fix right now.  Forgot to edit the yellow shaded 2019 values based on 2011-2018 average remaining losses in table below.  Extent ratio should be 1.14 and Area ratio should 1.17.  COMBINED AVERAGE stayed at 1.08. 
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi67.tinypic.com%2F316afb9.gif&hash=e3ff76f99fd96212d3150d4dca89d726)

The index value for each year is based on its average of ratios to the minimum value observed in 1979-2019 for each measure, not by the average ordinal ranking.

Observations/Speculation: 
-- 2012 stands alone as the lowest overall with 1st place ordinal rankings for all four measures.  (Technically, 2019 minimum thickness was lower, but only by insignificant margin.) 

-- 2019 is second to lowest, with one 1st, and three 2nd place rankings.  The estimated 2019 minimums for Extent and Area are substantially larger than for 2012.  The 2019 and 2012 minimums for Volume and Thickness are similar.
      The *2019 minimum Extent, Volume, and Thickness estimates based on the current season anomaly are lower than the estimate based on 2011-2018 average losses from latest observation date to minimum.  But the Area estimate is higher.  While 2019 still finishes second to 2012 for the average ratio, the gap is much narrower. 

-- 2016 and 2011 are close to each other for 3nd lowest overall ranking, followed by 2010 and 2017 in a tie for 4th place. 

-- The sequential rankings of 2010 (#5), 2011 (#4), and 2012 (#1) suggest that the 2012 minimum record may have been the culmination of a three year sequence of predisposing bad melt years vs. being entirely due to conditions in 2012. 
 
-- Except for 2007, there is a high degree of congruence between the 2D measures (Extent, Area) and the 3D measures (Volume, Thickness). 

-- Nine of the 10 lowest ranking years have been in the last decade.  All of the top ten ranks, except 2007 at #9, have occurred in 2010-2019.  At rank #12, 2014 is the only year in the most recent decade to not be in the top ten for lowest index overall value. 
Title: Re: 2019 vs 2012
Post by: Phil. on August 14, 2019, 04:21:58 PM
Has anyone given any consideration to the fact that 2012 was a leap year?. Because of the additional "leap day" we are, in essence, comparing 2019's todays with 2012's tomorrows. In the race to the bottom 2012 has been given a one day head start but it's just an illusion of our imperfect calendar.

I know NSIDC has considered this as their Chartic graph shows 2012 dats points (and those of all leap years) offset by one day. After leap day, that is.

It's better to use the Chartic approach and plot with respect to 'day of year' rather than calendar date.
Title: Re: 2019 vs 2012
Post by: sja45uk on August 14, 2019, 06:34:39 PM
It's better to use the Chartic approach and plot with respect to 'day of year' rather than calendar date.
Surely that just changes when the day jump occurs to the year after the leap year instead of the year of the leap year, and any use of day numbers as time axis labels would be bad.
Title: Re: 2019 vs 2012
Post by: petm on August 14, 2019, 07:00:35 PM
True about leap years, except... What's actually happening is the days are shifting relative to the astronomical calendar (e.g. summer solstice) every year. Leap years just reset this drift, in effect jumping back about 3/4 of a day relative to the previous year. Actually it's even worse, since to stay aligned with the astronomical calendar, the leap year has to be skipped 3 out of every 4 centuries.

I have the feeling that using day of year vs. date just makes it easier to plot Feb. 29th.

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

(https://gurvicharcom.files.wordpress.com/2018/01/gregorian-accuracy.jpg)
Title: Re: 2019 vs 2012
Post by: gerontocrat on August 14, 2019, 07:31:39 PM
LEAP YEARS -

I simply disappeared 29 Feb from the data from 1980 onwards.
Not a big deal as Feb 29 is at the end of the season so area / extent daily changes are minimal. Though in one year one of the minima or maxima was on Feb 29. Too bad.

In 2020 29 Feb will not exist in my data. So a day's holiday for me on March 1.

But 2020 will be a pain from March 1 onwards as I use the date to count the number of days so far in millions of "=offset(expression)" formulae. My spreadsheets, like topsy, just grew, and I failed to make a standard parameter sheet so one change would fix everything.

Shocking to be so cavalier.
Title: Re: 2019 vs 2012
Post by: petm on August 14, 2019, 07:37:03 PM
You murdered a whole day!?! :-0
Title: Re: 2019 vs 2012
Post by: gerontocrat on August 14, 2019, 08:14:38 PM
You murdered a whole day!?! :-0

Mass murderer!

One day every 4 years . 9 to date. Double figures next year!
Title: Re: 2019 vs 2012
Post by: Killian on August 21, 2019, 08:26:37 PM
Things have really calmed down compared to 2012, as we see on the charts, but here are the recent trends in numbers.

Current JAXA '19 - '12 extent: @ +370k.

Average JAXA extent change for August: @ -74k.
Average JAXA extent change for August prior to last seven days: @ -91k.
Average JAXA extent change over the last seven days: @ -44k.

Strong downward trend.

Same numbers for 2012:
Average JAXA extent change for August: @ -102k.
Average JAXA extent change for August prior to last seven days: @ -114k.
Average JAXA extent change over the last seven days: @ -81k.



Average JAXA daily extent change required to equal 2012 low: @ -51.5k.
(Average JAXA daily extent change required to equal 2016 low: @ -25.79k.)

Average JAXA daily extent change for Sept. 2012: @ -20k.
Things really slow down in September, so we'd need to see +11.5k more melt per day than we've seen the last week for the rest of the month. That +370k has to be gone by September, pretty much.

------------------------------------------------------------------

NSIDC Data

Current NSIDC '19 - '12 extent: @ +421k. (+330k 5-Day Avg.)
(Numbers are raw daily numbers, no averaging.)

Average NSIDC extent change for August: @ -67k.
Average NSIDC extent change for August prior to last seven days: @ -86k.
Average NSIDC extent change over the last seven days: @ -33k.

Strong downward trend here, too.

Same numbers for 2012:
Average NSIDC extent change for August: @ -102k.
Average NSIDC extent change for August prior to last seven days: @ -114k.
Average NSIDC extent change over the last seven days: @ -81k.


(Wow. I thought I'd made a copy/paste error, but no: Those NSIDC and JAXA 2012 numbers are that similar.)

Average NSIDC daily extent change required to equal 2012 low: @ -53.6k.
(Average NSIDC daily extent change required to equal 2016 low: @ -35.7k.)
Title: Re: 2019 vs 2012
Post by: AndyW on August 22, 2019, 08:48:35 AM
The Atlantic side near Spitzbergen shows more ice than the last couple of years currently.

In regards to 2012 I don't think 2019 is comparable at all due to the unusual weather in 2012  which 2019 has not had. 2019 is now following the general trend for August (so far) but will still be a very low year.

Personally I always ignore 2007 and 2012 as outliers and just look at the general trend.

Once the Arctic gets down to 2012 ice extent levels  repetitively, like it has compared to 2007 now, then that is worth noting.
Title: Re: 2019 vs 2012
Post by: seaice.de on August 22, 2019, 11:11:23 AM
Difference of August 22nd 2012 and 2019 (AMSR2 data so far until 5:18 UTC).