Support the Arctic Sea Ice Forum and Blog

Author Topic: The 2019 melting season  (Read 1161516 times)

aperson

  • Frazil ice
  • Posts: 171
    • View Profile
  • Liked: 75
  • Likes Given: 115
Re: The 2019 melting season
« Reply #6600 on: September 16, 2019, 01:15:41 AM »
@aperson
It's not a denialist mistake to be wrong. Everybody is wrong sometimes with their predictions. It's just a mistake. What do we call people who voted for BOE option THIS YEAR, during this melting season. Or do you think that was more realistic than weatherdude's prediction. They were just wronglike him. That is it. No conspiracies or hidden meanings behind every false prediction. Some are more realistic, some are less.

Hi colchonero, I agree with you. Regardless, I don't think you understand the context for this specific poster. They post denialist rhetoric on other forums like americanwx and then disappear whenever SIE or SIA goes back to low values. They seem to have registered here to do the same.

I agree with making falsifiable predictions and verifying them, in fact I have one coming up in just a few days that may bust that I will be posting about! It is not his prediction I have a problem with, it is his hubris: "Despite all of the hyperbole and wish casting, 2019 will not be in the top 3 lowest sea ice minimums on record in area or extent."

And note that this is not the first time this specific user has done this on this forum or elsewhere. Without this surrounding context I would have not been so judgmental.
computer janitor by trade

Rod

  • Frazil ice
  • Posts: 305
    • View Profile
  • Liked: 140
  • Likes Given: 8
Re: The 2019 melting season
« Reply #6601 on: September 16, 2019, 03:15:13 AM »
Bbr - you have some crazy predictions, but at least you always try to back them up and have some data to support your theories. 

Most of the posts on this forum for the last couple of months are not even worth reading. 

It is too bad.  I have loved following these discussions for the last few years. Anyway, keep pitching your theory. It is probably wrong in my opinion, but at least you provide something to consider.

Most of the other posts these days don’t provide anything other than opinions that have no factual basis.  That is why I stopped commenting, and why I don’t read these forums much anymore.

Good luck to you Bbr!   I have always respected your tenacity.  Keep posting the data so that others can consider what it means. 

Rod

  • Frazil ice
  • Posts: 305
    • View Profile
  • Liked: 140
  • Likes Given: 8
Re: The 2019 melting season
« Reply #6602 on: September 16, 2019, 03:48:52 AM »
PS. In case it wasn’t clear, I would rather read posts from someone who understands the science and posts his theories, even if I don’t agree with them, than keep reading all the BS from people who have made no effort to understand the science.

The discussion on this forum about the condition of the ice over the last few weeks has not been grounded in science. 

Zeug Gezeugt

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 9
  • Likes Given: 16
Re: The 2019 melting season
« Reply #6603 on: September 16, 2019, 06:05:31 AM »
I was wondering when you guys were going to wake up at the tail end of this season :) it's very interesting.

Totally, and 2019 has now fallen past the 2016 Jaxa extent minimum by 11,228km2 with just another 6,037km2 drop to go to join 2012 in the sub 4 million bracket.

How's that compacting high looking? Maybe good for another 48hrs? Anyone see any signs of decent refreeze yet?

Yossarian80

  • New ice
  • Posts: 6
    • View Profile
  • Liked: 11
  • Likes Given: 26
Re: The 2019 melting season
« Reply #6604 on: September 16, 2019, 08:27:03 AM »
How's that compacting high looking? Maybe good for another 48hrs? Anyone see any signs of decent refreeze yet?

All things equal the HP should expedite the refreeze this time of year, as associated clear skies allow IR and heat to escape to space.  But so far compaction and perhaps some stubborn bottom melt have been winning out.  I’d expect extent numbers to go a little lower from compaction as the high is forecast to stick around over the pack for a while, but it’s really just a guessing game.   It’s all just cosmetic as the ice is clearly trash... but it’s interesting to watch the forces compete and track where the final numbers end up.

The bad news is that the current pattern, and forecast for the next 5 days, looks closer to a typical dipole anomaly.  The high is forecast to slowly drift towards the Beaufort/NA side while low pressure moves towards the Kara.  If this pattern persists beyond 5 days we could quickly lose a lot of the thickest MYI to export.

sark

  • Frazil ice
  • Posts: 317
  • not a scientist
    • View Profile
  • Liked: 141
  • Likes Given: 77
Re: The 2019 melting season
« Reply #6605 on: September 16, 2019, 09:19:01 AM »
I was wondering when you guys were going to wake up at the tail end of this season :) it's very interesting.

Totally, and 2019 has now fallen past the 2016 Jaxa extent minimum by 11,228km2 with just another 6,037km2 drop to go to join 2012 in the sub 4 million bracket.

How's that compacting high looking? Maybe good for another 48hrs? Anyone see any signs of decent refreeze yet?

From 500mb down there is a packet of high height atmosphere trapped at the north pole up to 10 days out.
I am not a scientist

uniquorn

  • Nilas ice
  • Posts: 1452
    • View Profile
  • Liked: 696
  • Likes Given: 145
Re: The 2019 melting season
« Reply #6606 on: September 16, 2019, 10:05:24 AM »
Wipneus regional extent updated today.  https://sites.google.com/site/arcticseaicegraphs/regional
2019 CAB extent looking likely to join 2018 (brown) in a later refreeze. Not a trend yet but perhaps 2012 (yellow) was an indication of the shape of things to come.

edit: osisaf ice drift, sep8-15. Compaction in many areas, especially on the atlantic side west of FJL.
« Last Edit: September 16, 2019, 10:57:43 AM by uniquorn »

Jim Hunt

  • Young ice
  • Posts: 4267
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 264
  • Likes Given: 27
Re: The 2019 melting season
« Reply #6607 on: September 16, 2019, 10:48:57 AM »
JAXA/ViSHOP extent has now fallen below the 2016 minimum:

http://GreatWhiteCon.info/2019/09/the-2019-arctic-sea-ice-metric-minima/#Sep-16

Only 2012 left to beat!
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

El Cid

  • Grease ice
  • Posts: 526
    • View Profile
  • Liked: 157
  • Likes Given: 41
Re: The 2019 melting season
« Reply #6608 on: September 16, 2019, 02:31:43 PM »
No wonder this melt-season keeps on pushing: the seas are hot! The picture shows 20190913 SST vs the average of 2016,17,18 on the same day. Refreeze will likely be very slow based on this

Alexander555

  • Grease ice
  • Posts: 820
    • View Profile
  • Liked: 42
  • Likes Given: 34
Re: The 2019 melting season
« Reply #6609 on: September 16, 2019, 02:35:44 PM »
If you take the water north of Greenland, and i hope it's not a stupid question. The top layer, let's say the first meter. Is that colder or warmer than meltwater from Greenland ?

Aleph_Null

  • New ice
  • Posts: 92
    • View Profile
  • Liked: 45
  • Likes Given: 176
Re: The 2019 melting season
« Reply #6610 on: September 16, 2019, 02:40:43 PM »
Updated full-size versions available in the Nullschool Animations thread:
https://forum.arctic-sea-ice.net/index.php/topic,2905.msg228895.html#msg228895

Hindcast: 9/12 to 9/16, Forecast: 9/16 to 9/20. Wind + IWPD @ 850hPa (tiny version)

Iain

  • New ice
  • Posts: 62
    • View Profile
  • Liked: 18
  • Likes Given: 7
Re: The 2019 melting season
« Reply #6611 on: September 16, 2019, 03:07:23 PM »
2019 on 4.220 Million km2

Next nearest minima are: 2016 4.165; 2007 4.163.

"Here's the throw, here's the play at the plate, Holy cow....."
"If I have seen further than others, it is by standing upon the shoulders of giants." Isaac Newton

Davidsf

  • New ice
  • Posts: 22
    • View Profile
  • Liked: 5
  • Likes Given: 125
Re: The 2019 melting season
« Reply #6612 on: September 16, 2019, 03:30:53 PM »
Hello, I've been offline for several days in a small town on the CA coast without Internet.

+1 to the comments upstream in support of Jim H, Gerontocrat, Oren, Shared H, and others in effort to have a more science-based discussion.

Ossifrage

  • New ice
  • Posts: 27
    • View Profile
  • Liked: 73
  • Likes Given: 2
Re: The 2019 melting season
« Reply #6613 on: September 16, 2019, 03:31:20 PM »
Hey folks, sorry I've been away for a bit. Unfortunately, discussing the CAA ice here is necessarily low on my list of obligations. There's been some question about how the current ice regime will interact with the traditional "garlic press" process of the CAA. Short story: there's not much garlic left to press.

The way the garlic press is supposed to work, thick MYI at the southern boundary of the CAB gets forced into the steep channels of the CAA resulting in additional ridging and compaction. Over a number of years, that ice is eventually delivered south into melt-accessible areas. All of this works because the average prevailing wind pattern in the region forces that ice into the archipelago and then south (and, to some extent, southeast). This process is the primary reason why the ice in the CAA has traditionally behaved very differently from fast ice elsewhere (although the channel size and bathymetry of the archipelago would otherwise suggest that CAA ice is comparatively uninteresting fast ice).

This melting season did a lot of damage to these assumptions. Most of the season was spent with an atypical wind pattern that forced ice from the CAA/CAB boundary north against the CAB and west into the Beaufort. Thus, the Crack was born. Additionally, while this wasn't a record-setting year for CAA melt, it was pretty devastating nevertheless. Massey Sound was a killing field for ice. The Peary and Sverdrup Channels have some ice only by dint of latitude. In the Perry Channel, the surviving ice (primarily associated with the Viscount Melville Sound) has been forced by late storms to the southwest into areas that are frequent melt-out traps. The region that has been the temperature "cold core" of the archipelago in historical data wasn't actually very cold; ice in the PGAS is badly fragmented and exceptionally mobile, and even the sheltered ice in Wilkins Strait looks more than a little roughed up.

More importantly, what remains of the MYI -- the tiny, thin line of red on the age maps -- has been displaced north into the CAB, away from the CAA boundary. The Crack has filled as the wind patterns return to their expected directions, but the ice that filled the Crack is not that MYI stopgap, but an assemblage of broken bits transported in from elsewhere, including no small part of relatively young ice from the Lincoln Sea area. This is not robust garlic for the press. It's reasonable -- one hopes -- to assume that wind flow will indeed push ice south into the CAA. But this ice has demonstrated considerable structural weakness. So I expect floe disintegration rather than ridging as the disparate floes are forced together. Winter's cold will mitigate some of this, and the whole mess will freeze into a matrix of FYI (effectively fast) ice.

The overall trend for the Arctic is, of course, hotter with more melt. But as we've seen this year and the past couple, that melt is not always distributed in the same pattern year over year. If we get a year or two where the melt focus turns away from the CAA, and we don't see Crack 2 in 2020, the garlic press will likely crank back up for awhile anyway. Otherwise, within a couple of years, we may very well see what happens when the CAA explores a new modality (as we're already seeing with Bering/Chucki mechanics).

Paul

  • New ice
  • Posts: 43
    • View Profile
  • Liked: 9
  • Likes Given: 2
Re: The 2019 melting season
« Reply #6614 on: September 16, 2019, 03:55:24 PM »
Wipneus regional extent updated today.  https://sites.google.com/site/arcticseaicegraphs/regional
2019 CAB extent looking likely to join 2018 (brown) in a later refreeze. Not a trend yet but perhaps 2012 (yellow) was an indication of the shape of things to come.

edit: osisaf ice drift, sep8-15. Compaction in many areas, especially on the atlantic side west of FJL.

Compaction on the Atlantic side is the main cause for extent losses and I find it quite unbelievable how much ice we have lost in the past week  due to a set up no doubt 15+ years ago would be favourable for ice as another poster alluded too, high pressure promotes clearer skies therefore heat allowing to escape into space quicker and the compaction effects would be much smaller.

Would also add the troughing around the high would most definately produce colder air temperatures than it does these days, the ECM constantly wants to go colder in the medium range whilst the GFS does not and the reality is the GFS is always on the money more in these circumstances.

Shared Humanity

  • Young ice
  • Posts: 3935
    • View Profile
  • Liked: 403
  • Likes Given: 46
Re: The 2019 melting season
« Reply #6615 on: September 16, 2019, 04:28:04 PM »

Iain

  • New ice
  • Posts: 62
    • View Profile
  • Liked: 18
  • Likes Given: 7
Re: The 2019 melting season
« Reply #6616 on: September 16, 2019, 04:35:15 PM »
@ Ossifrage. Good concise summary. Thanks

I believe the CAA will become a significant export route for the CAB in the years to come.
"If I have seen further than others, it is by standing upon the shoulders of giants." Isaac Newton

RoxTheGeologist

  • Frazil ice
  • Posts: 457
    • View Profile
  • Liked: 125
  • Likes Given: 93
Re: The 2019 melting season
« Reply #6617 on: September 16, 2019, 06:37:45 PM »
JAXA/ViSHOP extent has now fallen below the 2016 minimum:

http://GreatWhiteCon.info/2019/09/the-2019-arctic-sea-ice-metric-minima/#Sep-16

Only 2012 left to beat!

That's quite a big gap. Perhaps not this season. I'm just hoping it drops another 7k so the result drops into the correct bin. By correct I mean the one I voted for.

Russell Burrows

  • NewMembers
  • New ice
  • Posts: 2
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6618 on: September 16, 2019, 07:34:48 PM »
Given the data that 2019 started the melt a week early is it thus perhaps that freezeing will perhaps be a week late thus giving a tiny push towards a lower extent than if freezeing began on October 1st?

Given that this year the permafrost is melting at a higher rate leading to increased methane with increased heat level retention.


Aluminium

  • Frazil ice
  • Posts: 403
    • View Profile
  • Liked: 341
  • Likes Given: 244
Re: The 2019 melting season
« Reply #6619 on: September 16, 2019, 08:34:35 PM »
September 10-15.

2018.

uniquorn

  • Nilas ice
  • Posts: 1452
    • View Profile
  • Liked: 696
  • Likes Given: 145
Re: The 2019 melting season
« Reply #6620 on: September 16, 2019, 11:07:09 PM »
amsr2-uhh overlaid onto mercator 0m temperature at 60% transparency, sep15. amsr2 0% concentration, normally dark blue, has been set to fully transparent.

Ossifrage

  • New ice
  • Posts: 27
    • View Profile
  • Liked: 73
  • Likes Given: 2
Re: The 2019 melting season
« Reply #6621 on: September 16, 2019, 11:19:25 PM »
I believe the CAA will become a significant export route for the CAB in the years to come.

Maybe.

Bathymetry and hydrology limit the rates that ice can move into and through the archipelago, especially compared to export through the Fram, into the Beaufort, or through the comparatively export-friendly Nares. But also, if we see a repeat of the wind conditions that created the Crack this year, CAB-to-CAA export may be limited to relatively minimal volumes, early and late in the melt season.

If such a shift in behavior does come to pass, the effective consequence will be for the CAA ice to act less like a traditional fringing sea and more like an area of quasi-seasonal fast ice. And, needless to say, that would be very bad for the CAB. It's too early to know, but that's something important to watch as the freezing season kicks in (is the CAA ice replenishment freeze-in-place, or CAB export?) and during next year's melt.

mabarnes

  • New ice
  • Posts: 40
    • View Profile
  • Liked: 17
  • Likes Given: 38
Re: The 2019 melting season
« Reply #6622 on: September 16, 2019, 11:22:30 PM »
Wipneus regional extent updated today.  https://sites.google.com/site/arcticseaicegraphs/regional
2019 CAB extent looking likely to join 2018 (brown) in a later refreeze. Not a trend yet but perhaps 2012 (yellow) was an indication of the shape of things to come.

edit: osisaf ice drift, sep8-15. Compaction in many areas, especially on the atlantic side west of FJL.

Compaction on the Atlantic side is the main cause for extent losses and I find it quite unbelievable how much ice we have lost in the past week  due to a set up no doubt 15+ years ago would be favourable for ice as another poster alluded too, high pressure promotes clearer skies therefore heat allowing to escape into space quicker and the compaction effects would be much smaller.

Would also add the troughing around the high would most definately produce colder air temperatures than it does these days, the ECM constantly wants to go colder in the medium range whilst the GFS does not and the reality is the GFS is always on the money more in these circumstances.

You can see the cracks closing up as the wind was blowin' like crazy ....

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7134
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 696
  • Likes Given: 457
Re: The 2019 melting season
« Reply #6623 on: September 16, 2019, 11:50:44 PM »
Over on the ASIB, I've just posted the late(st) PIOMAS update, and I just wanted to share the final half here, because it's how I view this melting season. Normally, I don't like it when people post long texts, but I'm the exception to that rule, of course.  ;)

Quote
Last month, I wrote at the end of the PIOMAS update:

Quote
From what I've seen on the Arctic Sea Ice Forum, written by commenters I've known for years and highly respect, my gut feeling says this year won't be able to break the 2012 records.

But for weeks now, I've been thinking of those prophetic words uttered by Peter Wadhams, back in 2007: 'In the end, it will just melt away quite suddenly.' I don't think all of it will melt away quite suddenly in coming weeks, but maybe more than one would expect just looking at the data.

This year is a great test that will tell us a lot about the importance of melting momentum.

To be honest, I expected a clearer melting momentum signal during this final phase of the melting season. Melting momentum took off slower than years like 2012 and 2016, but when it did take off, it was fireworks (see June 2019, one hell of a month). David Schröder's melt pond fraction maps, the SMOS pixel chart, the compactness charts, the Albedo-Warming Potential graphs, the snow cover graphs, more and more they were pointing to a massive build-up of melting momentum. On top of that, PIOMAS was showing that this year was very competitive volume-wise, and for five months in a row, 2019 was in the top 3 when it came to temperature records (August coming in lowest on record):



It was clear that the spell of extremely sunny, warm weather was ending during August. That, to me, was the great test for my melting momentum theory. Weather conditions switched, but for a week or so extent loss was keeping up with 2012's pace, despite the boost provided by the GAC. But then halfway through the month, things slowed down to a crawl after all (see red trend line):



So, what happened? Of course, there was a cyclone that was in a perfect position to disperse the ice, but there was so much weak ice that in my view, momentum should have gone on for a while longer.

There are two possibilities:

1) There wasn't as much melting momentum as I assumed.

2) Melting momentum is less important than I think it is.

As said, it took a while for melting momentum to get going. Timing is of the essence when it comes to breaking melting season records. May was actually very sunny this year, but most of the radiation coming from a Sun at a still low angle, got bounced off the pristine white ice. It may sound counterintuitive, but before the real melt ponding gets going due to open skies, cloudy weather is actually worse for the ice, because with clouds comes humidity and the clouds also block outgoing radiation. This can cause the snow on top of the ice to melt just a tiny bit, deforming the structure of the snow, making it more prone to melt when the sun starts to shine in earnest. 2019 came short in this respect, as evidenced by visual inspection of satellite images. Never mind the fact that the 2018/2019 freezing season was much less spectacular compared to the previous three winters, when it comes to temperatures and extreme weather conditions.

I'm still convinced that without a decent amount of melting momentum no records will be broken. That's why in years like 2016, 2017 and 2018 it was possible to announce at an early date that the 2012 record was safe. But conversely, a massive amount of melting momentum doesn't guarantee records either. Initial ice conditions and late stage weather obviously play important roles as well.

Maybe I'm emphasizing melting momentum too much, but I still feel kind of vindicated by recent developments on the extent front. Over the last week, just a small amount of weather conducive to melting has helped nudge 2019 below the 2007 and 2016 minimums, with quite an impressive run of daily drops. Tomorrow or the day after, the 4 million km2 mark could even be breached. I always thought that this year would come in second whatever would happen, and it looks like it has:



Either way, after almost 10 years of blogging, I'm now clearly seeing the contours of that first year when ice-free conditions will be reached (in other words, an ice cover smaller than 1 million km2, which amounts to ice-free for all practical purposes). It is preceded by a freezing season similar to that of 2015/2016, starts with the melt onset 2012 saw, builds up the massive melting momentum of 2019, and ends with the crazy weather of 2016. It makes me shudder to think what the satellite images will look like then. It may take more time than most cryospheric scientists think it will take, but unfortunately, that's not much of a comfort.

The ingredients are there, AGW is the cook.
Il faut comparer, comparer, comparer, et cultiver notre jardin

bbr2314

  • Nilas ice
  • Posts: 1763
    • View Profile
  • Liked: 159
  • Likes Given: 47
Re: The 2019 melting season
« Reply #6624 on: September 16, 2019, 11:56:48 PM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.

Perhaps it is nonsense, but that would put 4M KM^2 minimum as "normal" come 2021 (two years after 2019, and then we are down to one year separating these instances, i.e. it becomes each and every year), with each year thereafter likely to achieve a max under 2019, 2016, and 2007.

It should also be noted the last minimum above 5M KM^2 looks to be 2009. That is potentially about 11 years between the last minimum above 5M KM^2 and the last minimum above 4M KM^2 (using the step-trend above, that year would be 2020, or it may have already occurred).

We cannot say whether the remaining decline will follow on the same gradual continuum. Below 4M KM^2, the area / volume discrepancy inherently favors massive drops in area relative to volume as 0 is approached. I would think that there will not be another 11 years between the last 4M KM^2 min and the last 3M KM^2 min.

2009 is actually a great year to illustrate this increasingly gaping volume discrepancy. It has a September PIOMAS minimum of about 7,000 KM^3 (I can see the charts but not the exact #s). 2019 is probably going to come in around 4,000 KM^3. That is an approximate 45% volume decline, while area has only declined 25%ish (approx 5.25M KM^2 down to 4M KM^2).

At some point in the near future if volume decline continues, area is going to give out in a big way IMO, as the two most converge as 0 is approached.
« Last Edit: September 17, 2019, 12:07:03 AM by bbr2314 »

oren

  • Young ice
  • Posts: 4405
    • View Profile
  • Liked: 843
  • Likes Given: 1265
Re: The 2019 melting season
« Reply #6625 on: September 16, 2019, 11:58:34 PM »
Great writeup Neven.
I think you meant freezing season similar to 2016/2017?

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7134
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 696
  • Likes Given: 457
Re: The 2019 melting season
« Reply #6626 on: September 17, 2019, 12:04:18 AM »
Great writeup Neven.
I think you meant freezing season similar to 2016/2017?

Maybe both 2015/2016 and 2016/2017, I can't remember which one was worse, and why.

Hold on, I vaguely remember now 2017 starting out with an extremely low volume (according to PIOMAS). So yeah, maybe I did mean freezing season similar to 2016/2017.  ;D
Il faut comparer, comparer, comparer, et cultiver notre jardin

Klondike Kat

  • Grease ice
  • Posts: 731
    • View Profile
  • Liked: 37
  • Likes Given: 47
Re: The 2019 melting season
« Reply #6627 on: September 17, 2019, 12:07:04 AM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.

Perhaps it is nonsense, but that would put 4M KM^2 minimum as "normal" come 2021 (two years after 2019, and then we are down to one year separating these instances, i.e. it becomes each and every year), with each year thereafter likely to achieve a max under 2019, 2016, and 2007.

It should also be noted the last minimum above 5M KM^2 looks to be 2009. That is potentially about 11 years between the last minimum above 5M KM^2 and the last minimum above 4M KM^2 (using the step-trend above, that year would be 2020, or it may have already occurred).

We cannot say whether the remaining decline will follow on the same gradual continuum. Below 4M KM^2, the area / volume discrepancy inherently favors massive drops in area relative to volume as 0 is approached. I would think that there will not be another 11 years between the last 4M KM^2 min and the last 3M KM^2 min.

Does that mean we are approaching an asymptote at 4 M?

bbr2314

  • Nilas ice
  • Posts: 1763
    • View Profile
  • Liked: 159
  • Likes Given: 47
Re: The 2019 melting season
« Reply #6628 on: September 17, 2019, 12:49:35 AM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.

Perhaps it is nonsense, but that would put 4M KM^2 minimum as "normal" come 2021 (two years after 2019, and then we are down to one year separating these instances, i.e. it becomes each and every year), with each year thereafter likely to achieve a max under 2019, 2016, and 2007.

It should also be noted the last minimum above 5M KM^2 looks to be 2009. That is potentially about 11 years between the last minimum above 5M KM^2 and the last minimum above 4M KM^2 (using the step-trend above, that year would be 2020, or it may have already occurred).

We cannot say whether the remaining decline will follow on the same gradual continuum. Below 4M KM^2, the area / volume discrepancy inherently favors massive drops in area relative to volume as 0 is approached. I would think that there will not be another 11 years between the last 4M KM^2 min and the last 3M KM^2 min.

Does that mean we are approaching an asymptote at 4 M?
Maybe temporarily but I think the volume decline means it will not hold. Maybe it is a situation of once the asymptote is breached twice consecutively it cannot recover and spirals to near 0. Until it happens two years in a row, or rather until now, there has been sufficient momentum for temporary recoveries. As we can see in the year over year charts that momentum has been fading.

philopek

  • Frazil ice
  • Posts: 423
    • View Profile
  • Liked: 149
  • Likes Given: 40
Re: The 2019 melting season
« Reply #6629 on: September 17, 2019, 12:55:08 AM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.


As far as I remember that's what "be cause" is posting in his signature on a daily base, at least interesting indeed

Jim Hunt

  • Young ice
  • Posts: 4267
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 264
  • Likes Given: 27
Re: The 2019 melting season
« Reply #6630 on: September 17, 2019, 01:44:59 AM »
From Stefan Hendricks in the build up to MOSAiC:

http://GreatWhiteCon.info/2019/09/the-mosaic-expedition/#comment-289460

Freeze-up now in progress around the MOSAiC expedition start region. Higher ice concentrations than a week ago.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Paul

  • New ice
  • Posts: 43
    • View Profile
  • Liked: 9
  • Likes Given: 2
Re: The 2019 melting season
« Reply #6631 on: September 17, 2019, 02:26:48 AM »
Regarding the debate around melting momentum, I think it does have an affect but remember one of the reasons why(and a few others)  thought a record low was not likely was because the CAB looked more compact earlier on in the summer season unlike in years like 2012 and 2016 where it looked more disperse. There was a debate what's worse for the ice, dispersion or melt ponding? Maybe the answer is both are just as bad as each other, I've no doubt if the CAB looked as disperse as it did in 2016, we be alot closer to 2012 or even surpassed it because unlike in 2016, the ice at the lower latitudes of the basin quickly melted out. However melt ponding over the ESS really caused huge momentum during July as the ESS ice rapidly melted out in the end hence a lower extent because there is no arm of ice stretching out towards the ESS this year.

echoughton

  • New ice
  • Posts: 92
    • View Profile
  • Liked: 14
  • Likes Given: 46
Re: The 2019 melting season
« Reply #6632 on: September 17, 2019, 04:26:42 AM »
2019 on 4.220 Million km2

Next nearest minima are: 2016 4.165; 2007 4.163.

"Here's the throw, here's the play at the plate, Holy cow....."
[/quote

STOP RIGHT THERE!!! ........]

tzupancic

  • New ice
  • Posts: 50
    • View Profile
  • Liked: 10
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6633 on: September 17, 2019, 06:55:33 AM »
It looks like the JAXA Arctic Sea Iced extent has now gone below 4 million... to

3991187

Often Distant

  • New ice
  • Posts: 35
    • View Profile
  • Liked: 12
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6634 on: September 17, 2019, 07:05:08 AM »
Following recent snowfall, open water in the Nares Strait has begun freezing over.
Both worldview images are from the 16th of September, switching between Aqua/MODIS and Terra/MODIS layers.
With the closing of the polynya at the entrance, export is increasing.


blumenkraft

  • Grease ice
  • Posts: 967
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 455
  • Likes Given: 631
Re: The 2019 melting season
« Reply #6635 on: September 17, 2019, 07:38:50 AM »
Sorry, Often Distant, i have to correct you on that one. There is no refreezing going on in Nares ATM. All that floes are from Lincoln. Looks like the current has picked up again. I reported yesterday in the Nares Strait thread:

https://forum.arctic-sea-ice.net/index.php/topic,176.msg228982.html#msg228982


Edit: Bullshit!
« Last Edit: September 17, 2019, 08:56:57 AM by blumenkraft »
Refugees welcome

Often Distant

  • New ice
  • Posts: 35
    • View Profile
  • Liked: 12
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6636 on: September 17, 2019, 07:50:03 AM »
Freeze onset appears clearer on sentinel hub playground, which sadly is now a paid subscription service. A 30 day free trial is all the general population now has access to.

sark

  • Frazil ice
  • Posts: 317
  • not a scientist
    • View Profile
  • Liked: 141
  • Likes Given: 77
Re: The 2019 melting season
« Reply #6637 on: September 17, 2019, 08:15:44 AM »
We've been way off the 7 day forecast on AO strength for a while.

For a little wider view of what we're dealing with, here's a pasted together 2 charts from https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml
I am not a scientist

blumenkraft

  • Grease ice
  • Posts: 967
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 455
  • Likes Given: 631
Re: The 2019 melting season
« Reply #6638 on: September 17, 2019, 08:56:01 AM »
Freeze onset appears clearer on sentinel hub playground, which sadly is now a paid subscription service. A 30 day free trial is all the general population now has access to.

Ops, i was wrong, you were right, Often Distant! In the Petermann fjord and it's entrance in NS, there is indeed refreezing.

BTW, do you know EO-Browser?

https://apps.sentinel-hub.com/eo-browser/?lat=80.9997&lng=-61.4392&zoom=11&time=2019-09-15&preset=1_TRUE_COLOR&gainOverride=0.2&gammaOverride=0.5&datasource=Sentinel-2%20L2A
Refugees welcome

Often Distant

  • New ice
  • Posts: 35
    • View Profile
  • Liked: 12
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6639 on: September 17, 2019, 09:33:22 AM »
Thanks blumenkraft. I will be frequenting the EO browser for sure.

Jim Hunt

  • Young ice
  • Posts: 4267
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 264
  • Likes Given: 27
Re: The 2019 melting season
« Reply #6640 on: September 17, 2019, 10:19:58 AM »
It looks like the JAXA Arctic Sea Iced extent has now gone below 4 million

I'd noticed that too. It most certainly has. Just!

On the "refreeze" front I don't see any "new ice" on the Canadian stage of development charts yet. However see also the Russian AARI maps, which are now showing some "nilas":

http://nsra.ru/en/navigatsionnaya_i_gidrometinformatsiya/icecharts.html

By way of example:



« Last Edit: September 17, 2019, 10:34:23 AM by Jim Hunt »
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

be cause

  • Grease ice
  • Posts: 860
  • Citizenship .. a Lurker gets asylum
    • View Profile
  • Liked: 234
  • Likes Given: 198
Re: The 2019 melting season
« Reply #6641 on: September 17, 2019, 10:24:24 AM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.


As far as I remember that's what "be cause" is posting in his signature on a daily base, at least interesting indeed


the art of the ( not so ) subliminal message ? . b.c.
« Last Edit: September 17, 2019, 01:16:59 PM by be cause »
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Juan C. García

  • Nilas ice
  • Posts: 1457
    • View Profile
  • Liked: 463
  • Likes Given: 494
Re: The 2019 melting season
« Reply #6642 on: September 17, 2019, 01:36:26 PM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.


As far as I remember that's what "be cause" is posting in his signature on a daily base, at least interesting indeed


the art of the ( not so ) subliminal message ? . b.c.
I see more random behavior:
2002 was a bad year (September record versus previous years).
2005 was a bad year  (September record versus previous years).
2006 was worse than in 2005 in must parts of May-August, but not in September.
2007 was a bad year  (September record versus previous years).
2010 was a bad year.
2011 was a bad year (Bremen said that it broke 2007 daily minimum, but it happened at the beginning of September and the freezing season started early, so NSIDC September average doesn't show this low value).
2012 was the terrible year in summer  (All-time September record).
2015-2019 were bad years in winter & spring.
2016 was very bad on the extent and 2017 very bad on volume (2017 is all-time low-volume record on the PIOMAS year average), but not as bad as 2012 at the end of summer.

NSIDC sees 2007 as the second-lowest on extent. I think that this could continue to be the case, once that we have the NSIDC 2019 September average. But other agencies will not agree. ADS NIPR looks for the lowest daily value (not the lowest September average) and AMSR2 has more accuracy than NSIDC measurements. So 2012, 2016 and now 2019 will be the ADS NIPR three lowest years. The same will maybe apply to Bremen (or they may include 2011).   

--> Almost all the above comments are base on the extent because it is the measure that it is easy to follow on a daily basis, but volume tells another story. If you look on a decadal average and compare it to a 1979-2000 base, the Arctic lost almost 1/3 of volume in 2000-2009 and almost 2/3 in 2010-2019. 2007 low value is broken in several years.

More important: On PIOMAS September volume, 2019 is going to be almost as bad as 2012.   

« Last Edit: September 17, 2019, 04:10:58 PM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Aleph_Null

  • New ice
  • Posts: 92
    • View Profile
  • Liked: 45
  • Likes Given: 176
Re: The 2019 melting season
« Reply #6643 on: September 17, 2019, 05:03:43 PM »
No attachment needed. The view of the whole icecap in Worldview is stunning today. Go see it.

Niall Dollard

  • Frazil ice
  • Posts: 477
    • View Profile
  • Liked: 98
  • Likes Given: 29
Re: The 2019 melting season
« Reply #6644 on: September 17, 2019, 06:07:05 PM »

On the "refreeze" front I don't see any "new ice" on the Canadian stage of development charts yet.


A lump of grey ice (purple shade in image) here Jim. But it's more really in the Arctic Ocean (at 80 N) and away from Canadian inshore waters. Probably something similar to what Mike Horn's boat was plowing through.

 https://forum.arctic-sea-ice.net/index.php/topic,2886.msg229100.html#msg229100

Jim Hunt

  • Young ice
  • Posts: 4267
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 264
  • Likes Given: 27
Re: The 2019 melting season
« Reply #6645 on: September 17, 2019, 07:08:40 PM »
A lump of grey ice (purple shade in image) here Jim.

Thanks Niall.

I didn't look at that one, because the CIS Eureka map is currently completely blank. I foolishly assumed the same would apply to the Arctic Basin, and that I'd therefore have to wait for the update of the weekly map.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

RoxTheGeologist

  • Frazil ice
  • Posts: 457
    • View Profile
  • Liked: 125
  • Likes Given: 93
Re: The 2019 melting season
« Reply #6646 on: September 17, 2019, 07:14:03 PM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.

Perhaps it is nonsense, but that would put 4M KM^2 minimum as "normal" come 2021 (two years after 2019, and then we are down to one year separating these instances, i.e. it becomes each and every year), with each year thereafter likely to achieve a max under 2019, 2016, and 2007.

It should also be noted the last minimum above 5M KM^2 looks to be 2009. That is potentially about 11 years between the last minimum above 5M KM^2 and the last minimum above 4M KM^2 (using the step-trend above, that year would be 2020, or it may have already occurred).

We cannot say whether the remaining decline will follow on the same gradual continuum. Below 4M KM^2, the area / volume discrepancy inherently favors massive drops in area relative to volume as 0 is approached. I would think that there will not be another 11 years between the last 4M KM^2 min and the last 3M KM^2 min.

Does that mean we are approaching an asymptote at 4 M?
Maybe temporarily but I think the volume decline means it will not hold. Maybe it is a situation of once the asymptote is breached twice consecutively it cannot recover and spirals to near 0. Until it happens two years in a row, or rather until now, there has been sufficient momentum for temporary recoveries. As we can see in the year over year charts that momentum has been fading.

I suspect the total insolation above 80°N (from observation) is too little to melt the ice that forms on a yearly basis. The ice will have to be thinner, so less FDD days or more export. That equates to warmer and wetter weather for 9 months of the year. That or some good big storms to mix the ice with the warmer water below the halocline or in the adjoining seas during the summer.

The area within 80°N is 3883031 km2 (please someone correct that math if I'm wrong!) so perhaps that is where we will asymptote, give or take a little due to land masses causing local patterns. That may persist until we build up enough imbalance between the polar and equatorial temperatures to drive additional heat into the Arctic in the form of big warm storms.



 

Russell Burrows

  • NewMembers
  • New ice
  • Posts: 2
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: The 2019 melting season
« Reply #6647 on: September 17, 2019, 07:58:41 PM »
Given increased heat retention due to increased methane from melting permafrost and reduction of arctic ice system flexibility due to reduction of system volume.

Plus the system impact of probable  algae formation plus microplastics for 2020 in some areas.

These factors may lead to more system vulnerability.

<Edit Neven: Welcome to the ASIF. Comments here should be mostly about this year's melting season and not about the future of Arctic sea ice in general.>

« Last Edit: September 17, 2019, 08:26:33 PM by Neven »

philopek

  • Frazil ice
  • Posts: 423
    • View Profile
  • Liked: 149
  • Likes Given: 40
Re: The 2019 melting season
« Reply #6648 on: September 17, 2019, 09:17:37 PM »

the art of the ( not so ) subliminal message ? . b.c.

Correct and intended and apparently well done ;) ;)

Pavel

  • Frazil ice
  • Posts: 197
    • View Profile
  • Liked: 17
  • Likes Given: 2
Re: The 2019 melting season
« Reply #6649 on: September 17, 2019, 09:28:59 PM »
One can see clearly on the Worldview that the new ice is forming on the nothern Greenland fjords and in the Nares strait. Some real (bottom) melting occur only in the Beaufort and Greenland seas. But in general the melting season is over and only compaction can decrease extent