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Messages - kynde

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1
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 18, 2020, 04:24:24 PM »
Here's a quick summation of the 2020 melt season, at 2 week intervals. Max extent was around the March 4th, while min seems like Sept 13th (so the final period is not quite 2 weeks!).

I should probably mention the top one is an animation. Click to play!

2
Arctic sea ice / Re: The 2020 melting season
« on: August 09, 2020, 09:33:10 PM »
This remarkable freeze/melt cycle has been unfortunate but perhaps inevitable, putting us literally in uncharted waters with regards to massive climate change impacts.

It’s easy to forget, as the post-BOE forum properly notes, that once upon a time the Barents, Baltic, Bering, Baffin. Chukchi, and Kara hosted millions of sq km of year-round ice. (And that not so long ago, 1000 m thick ice gouged the Lomonosov ridgetop.) On 08 Aug 2020, 38% of the remaining ice (the Arctic Ocean basin, was open water. Vast areas of tundra are free of reflecting snow as well. We’re already well into BOE in most respects.

What’s going on at the moment is baffling, notably between Greenland and the north pole. It’s clear we don’t really understand the current physical state of the ice. Thus even if surface weather were predictable three days out, where things will end up by mid-October still remains up in the air.

However we do have a good grip on some of the pre-conditioning events that have brought the ice to its current state:

-1- The melt season really began in the previous freeze season, even earlier. Vast areas of surprisingly thin 0.3m ice remained in the Laptev when the Polarstern moored on Oct 4th. That and a slow start to freeze-up are documented by thousands of km of ship thickness transects with no graduating SYI floes thick enough to stand on for Mosaic. (T Krumpen http://dx.doi.org/10.5194/tc-14-2173-2020)

-2- The TransPolar Drift over winter, as accurately imaged in Ascat time series, bore little resemblance to recent years in two key respects: months of very rapid Fram-ward displacement and extensional engagement of ice to the pole and beyond. Often the ice drift is just circumpolar.

-3- The whole icepack does not rotate CW with the TPD but rather participation is demarcated by immense  curvilinear leads, newly visualized in a dockside posting by L Kaleschke and enhanced on the Mosaic forum by directional convolution. These fracture lines, coincidentally or causally, approximately delimit the puzzling openings to the pole above Morris Jesup. A lot of MYI ice between Greenland and the pole was fractured by lead formation.

-4- Missing this year was any significant CW rotational movement of thick ice out of the western CAB. While this ice has never moved further than a half gyre in the last ten years of tracking, commonly a strip of CAB ice moves to inevitable melt in the warmer open seas of the Chukchi (which might be called internal export).

-5- Export out the Fram was robust during the TPD, pushing everything ahead of a 500 km east-west line through the initial position of the PS to oblivion in the Greenland Sea. Behind this line, newly formed Laptev ice filled the growing open water gap to shore. However, since mid-May, export out the Fram, SV-FJL gap, Bering Strait, CAA garlic press and Nares have all been inconsequential (and will remain so, too little time is left).

-6- A record heat wave off Ellesmere in mid July coupled with persistent easterly winds melted vulnerable matrix ice joining floes, enabling churning of offshore ice into residual rubble. The observed movement to the west is not unusual but it was far more narrowly restricted to the CAA coast in past events. The main CAB ice pack, being no longer attached to coastal land or ocean bottom, might be set adrift to elsewhere by persistent winds from the south. We’ve not yet seen that game-changer.

-7- The Pacific-side cyclone centered on July 27th hit like a tornado at 75º/-160º decimating the ice, on Sentinel-1 and WorldView, making clear that error-prone thickness and area/extent whole-ocean numbers don’t capture key issues such as ice mechanical strength, internal pressure or response to stress.

Both the Chukchi and slow-melting Beaufort were pre-conditioned by dispersion for flash lateral and bottom melt after the storm; note insolation today at 75º surprisingly is still 64% the strength the week centered on solstice (4th image below) but has to get through clouds and escape low angle surface reflection.

Are these independent events or somehow consequent to a single master change (such as breakdown trend of equatorial heat gradient as manifested in the jet stream)? Yes to a certain extent but this view has to be distinguished from the slot machine model put forward by Csnavywx in #4662.

That is, the multi-decadal downward trend of ice has created a set-up for which a coincidental confluence of bad weather events over a single freeze/melt cycle sequentially sum to an ice disaster. Even bland weather from here to October may suffice for a seriously below-trend outcome. Regardless of how the season turns out, as @Zlabe notes, fractional BOE has gone on all summer.

The files below expand or animate with a click. File names explain the topic addressed. I thank uniquorn for valuable discussions. Clouds are removed by setting a sequential five day AMR2 stack to 'darken only' in gimp.

3
Arctic sea ice / Re: MOSAiC news
« on: August 09, 2020, 09:10:02 AM »
Sorry Oren, but if you snip the pseudoscience from OTG's post above, I'll remove this post.

OTG has retreated with all claims except the following:

Quote
The comment about rock melting, this does happen under icestreams, so you'd get superheated steam along with the water expelled into the drainage system, before the runaway rate of melt causes a crash sudden quench and the base flash freezes to the bedrock again.

This should have been snipped since it is totallly unfounded, unrealistic, incredible and without any supporting evidence. We Scandinavians learn in school what bedrock looks like after being covered by a few kms of ice during the deep ice age, and scoring tracks left by big rocks scratching into the underlying bedrock are commonly seen. Surface melting is never seen, and just to imagine that it could happen is indicative of a total lack of scientific reasoning and real-world understanding.

4
Arctic sea ice / Re: The 2020 melting season
« on: August 01, 2020, 07:02:21 AM »
July 1-31 (fast).

5
Arctic sea ice / Re: The 2020 melting season
« on: July 29, 2020, 01:21:51 AM »
By the way, the waves in 2012 in Barrow were much smaller.

In depth analysis at "Snow White's" web site:

https://GreatWhiteCon.info/2015/03/sea-ice-and-swells-in-the-beaufort-sea-in-the-summer-of-2014/

6
Arctic sea ice / Re: The 2020 melting season
« on: July 29, 2020, 12:06:37 AM »
Edit: windy shows almost 2m waves with 6s period hitting barrow and 2.6m with 7s period further north hitting the ice. That should give a proper stir.

20 seconds is required for a proper stir!

(N.B. FooW in joke)

7
Arctic sea ice / Re: The 2020 melting season
« on: July 27, 2020, 03:43:53 PM »
Side by side of July 26th in 2012 and 2020.

8
Arctic sea ice / Re: The 2020 melting season
« on: July 27, 2020, 08:54:24 AM »
Thankfully these crazy predictions of 2.5million are now gone. Looks like a stall will mean we finish in the pack. Though probably whether we come 2nd or 3rd will be the only question. Think 2019 and 2020 will be very close at the end despite everything. Hopefully August will be a boring month for the ice.

So you expect the endless torching over the CAA and Eastern CAB to not keep melting the ice??  Which is already showing up on modis when the clouds clear out filled with holes...

What do you think this 972MB vortex puking out rain all over the Beaufort, Chuckchi, and Western CAB in concert with 20-30KT winds over 36-48 hours is going to do to ice that is truly 50-60 percent Concentration with MILES of OPEN WATER between the DECIMATED CHUNKS of ice?

And when that system winds down we still have another 40 days of ice loss to go.

You literally call predictions for new record lows crazy while giving no evidence to back up your new prediction of 2nd or 3rd lowest. I assume you are talking about extent.

Well you did cite a few days of slower losses while winds are in the reverse dipole position.  Which hasn't stopped melting.  Just compaction.


I'm not trying to be a dick but people post here putting huge effort and time backing there opinions and thoughts with great depth and thoughtfulnes and you dismiss that as crazy while offering no empirical evidence. 


I guess you have historical precidence on your side.  It would be nice if you would back up why you think 2020 is probably going to end up tied with or below 2019.

You may be right.  But it's pretty cheap to call the incredible analysis that dozens of members here contribute as crazy and then not actually offer any substance to back youe position.  Please no hard feelings.  Have a good night/day

 





9
Arctic sea ice / Re: The 2020 melting season
« on: July 23, 2020, 03:32:13 AM »
Michael,

I'd like to preface this by saying that I don't even like to guess at where the season will finish, because it seems like an easy way to be wrong about one more thing in life. I have made some predictions about the end of the month, which are modest and based off of long term loss patterns for the various arctic seas. So I am not claiming to know about what position this year will finish in, and your belief in 3rd place or above is not really what bothers me. What I find slightly off putting about your posts is the degree of certainty you speak with, in spite of the fact that many long term observers on this forum have put forward evidence that should at least make you question your conclusions. Also, you never admit when called out on something (such as your comment about the open water being "mostly on the fringes").

As for your specific replies:

Why would it be just as likely that there is more area and not less given the record low extent? You're treating this as a logical problem (area could be either higher or lower, so there's 50% chance each way), whereas such a statement must be justified empirically.

I would like to compare to 2019, for example, but 2019 had a low pressure system over the arctic for almost all of July, so it's difficult to make comparisons for most of the ice. Clearly the Beaufort was in worse shape in 2019, but that's about all that is clear (other than that way more momentum has been built up this year due to insolation).

As for the ridging/rafting, no one was questioning that this happens, so your PIOMAS link offers nothing to the discussion. A paper was already put forward on the difference in the mechanics between rafting and ridging. The question was whether we could expect this to occur during melt season on structurally compromised ice, due to compaction. You haven't provided any new information on that question.

10
Arctic sea ice / Re: The 2020 melting season
« on: July 22, 2020, 12:06:44 PM »
I think there is a miscommunication here. The ice is/was "compacting", meaning it was generally moving towards the center of the pack, as an expected result of the high pressure and anti-cyclonic winds. I think all/most posters agree on that.
However, is the ice compact, meaning with no small holes inside the pack? I think many posters are saying no, it is not compact, since area has disappeared while the ice was moving northward, thus there is less ice covering a smaller extent.
Is the ice strong and defensible? I think many posters are saying no.
And have ice floes stacked on top of one another due to the northward movement, as happens with pressure ridges in winter? I think most/all posters now agree that no.

BTW, great animation Pagophilus.

11
Arctic sea ice / Re: The 2020 melting season
« on: July 19, 2020, 10:39:29 PM »
This map posted by Zack Labe today (on Twitter @ZLabe) showing the January to June 2020 temperature ranks is pretty incredible!

Notice there are no blue colors anywhere on the map. And, Siberia 🔥🔥🔥!

 

12
Arctic sea ice / Re: The 2020 melting season
« on: July 17, 2020, 05:47:38 AM »

ALL RIGHT I'M DONE YOU GUYS ENJOY THIS NONSENSE

Yikes, Is Frivolous leaving? But the best/scariest part of the melt season is just coming up! I don’t know about the rest of you, but I’d much rather have Friv on this forum than the sea-lioning commenter he’s ranting about.

Not leaving.

I don't want anyone else to leave. Including Phoenix.

I WANT EVERYONE TO EXIST HERE WITH INTEGRITY AND GENUINITY.

ITS HARD TO BELIEVE THAT IS THE CASE WITH THESE NONSENSICAL  TALKING POINTS THAT ARE NOT BACKED WITH FACT OR DATA AT ALL.


13
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: July 15, 2020, 05:53:06 PM »
I sent an email to NSIDC about their data. A quick reply!
Note they say problems with the last 2 days data. So maybe yesterday's posting on NSIDC data is a load of......

You have been warned.
_______________________________________________________
Nic, Jul 15, 2020, 8:51 AM MDT:
Dear Matthew,

Thank you for contacting NSIDC. Thank you for catching this issue. We have been experience issues with ingesting the data used for the sea ice analysis for the past two days, and are currently performing planned maintenance. However, it isn't immediately obvious what caused discrepancies in previous months.

I've sent a note the Arctic Sea Ice News and Analysis team, and I'll get back in touch with you shortly.

Best regards,
Nic

14
Arctic sea ice / Re: The 2020 melting season
« on: July 15, 2020, 02:03:11 PM »
A full explanation of the new model will soon follow in an extra topic.
Looks interesting and useful, though I don't understand something. TJ is almost nothing for the Arctic. Even 1000 TJ is almost nothing. 1 W/m2 * 5M km2 * 1 day = 432000 TJ.

15
Arctic sea ice / Re: The 2020 melting season
« on: July 11, 2020, 11:25:05 AM »
You’re welcome Blumenkraft  :) it’s easier to know when you’re from an ice climbing background since most ice that is formed in a non glacier environment is from freeze and thaw, on the other hand I didn’t know that glaciers were created by compression until a couple years ago, so you win some, you lose some
"Bluing" of ice crystals is a result of going from smaller to larger crystals. The larger the crystal, the more red light is absorbed.

16
Arctic sea ice / Re: The 2020 melting season
« on: July 07, 2020, 02:40:28 AM »
Dr. Judah Cohen has posted a new long term outlook for arctic weather patterns.

It is very technical (I have read it three times and I still don’t understand it), but some of our amateur meteorologists might enjoy reading it.

“Arctic Oscillation and Polar Vortex Analysis and Forecasts
July 6, 2020”

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

Some highlights:

“Impacts

Certainly, one of the biggest if not the biggest weather news story of the summer so far has been the high-pressure system/heat dome that setup over Siberia in June leading to record breaking high temperatures and wildfires across Siberia.  The exceptional warmth has caused sea ice to melt at a record pace in the Laptev Sea adjacent to Siberia and has contributed to an overall acceleration of sea ice melt for the entire Arctic basin over the past several weeks.  That high pressure system that sat over Siberia for much of June has now drifted into the Central Arctic centered near the North Pole.

Therefore, the circulation pattern in the Central Arctic is likely to be very different from recent Julys.  The circulation in the Central Arctic has been dominated by low pressure resulting in relatively cloudy, cool weather.  So even though Arctic sea ice at the end of the winter was at or near record low extent no new record annual minimums have been observed since 2012 because summer low pressure in the Central Arctic slowed sea ice melt. However, at a minimum for the first half of July, the Central Arctic will be dominated by high pressure favoring relatively sunny and warm weather, which is conducive to accelerated sea ice melt.  There does seem to be a higher probability that the sea ice minimum in 2020 will be lower than recent summers and may even challenge the record low of summer 2012.”


I also thought this comment was interesting based on some discussions upthread:

“Longer Term

30–day

The latest plot of the polar cap geopotential height anomalies (PCHs) currently shows normal to above normal PCHs in both the troposphere and the lower stratosphere with normal to below normal PCHs in the mid-stratosphere (Figure 11).  However, PCHs in the lower stratosphere are predicted to reverse to normal to below normal while PCHs in the troposphere are predicted to remain mostly positive (Figure 11).  The GFS forecasts of a reversal to cold stratospheric PCHs have been overdone much of the spring and I wouldn’t consider the forecast reliable.”

The first Figure below is Figure 11.  The second one is Figure 13 in the article.


17
Arctic sea ice / Re: The 2020 melting season
« on: July 05, 2020, 07:47:47 PM »
I'm here. I learned from A-Team that, because sea ice is a deformable medium, the best thing to do is to look at markers of where it is moving. There's no disagreement that high pressure over the pole leads to compaction around the pole and low pressure leads to dispersion. That said, the Arctic has many obstacles that cause sea ice to pile up, rotate and thin. Moreover, high pressure causes easterly winds along the shelf margins which induce upwelling. Persistent winds of 10 days or more can cause strong coastal upwelling events which may bring up stored heat from subsurface layers.

The worst set up for sea ice is low pressure over the pole in the winter and high pressure in midsummer. Guess what? That exactly what's happened this year.


18
Arctic sea ice / Re: The 2020 melting season
« on: July 05, 2020, 12:28:06 AM »
Am I correct in remembering that this kind of sunshine can cause up to 5cm/day of top melt? So this week long HP could melt 30cm off of wide swaths of the ASI?

If the water under the ice warms up, how much ice starts melting per day? 0.5cm? 1cm? Do we know how fast bottom melt was going in other years, when there were still buoys in the ice measuring such things?

See for example this 2011 paper from Don Perovich:

https://tos.org/oceanography/assets/docs/24-3_perovich.pdf

Quote
Surface melt in 2007 was typical for the Beaufort Sea, with melt starting in early June and a total of 0.7 m of surface melt. The difference in 2007 was the extremely large 2.1 m of bottom melting. There was a gradual buildup of heat in the upper ocean in July and August. Bottom melt rates increased throughout the summer, reaching peak values of 0.1 m d–1 in late August.

19
Arctic sea ice / Re: MOSAiC news
« on: June 28, 2020, 01:48:54 PM »
If 61 has a longer string I'd love to see, say the last month of the whole thing

20
Arctic sea ice / Re: Arctic Image of the Day
« on: August 12, 2019, 07:51:15 AM »
Here are a couple of photos I got while flying over the Arctic, from Toronto to Hong Kong on August 1st. (yes, I feel bad about flying due to emissions, but it's not a vacation, we've moved to Jakarta for my wife's work. we will also buy some offsets to try to compensate a bit.)

We were trying to sleep through the 15 hour overnight flight, but I managed to some how wake myself up at the right time to open the window blind and blind myself with the glare.

Again, taken on Aug. 1st, somewhere between Greenland and the North Pole. It seems like a lot of water visible in the leads for this area, even for this time of year. Maybe it's normal recently, but I can't imagine it would've been normal when this area used to be dominated by multiyear ice.

If you want to see the full size images, DM me and I'll email them to you.

cheers,
m

21
Arctic sea ice / Re: The Rammb Slider Thread
« on: August 04, 2019, 04:44:56 PM »

Yes, mine is shorter. rammb eats up my broadband volume. Thanks for the links. I definitely couldn't go searching for these.


Here's my effort to make RAMMB a bit more user friendly for those who have internet struggles with the demands of the slider.  I can add more upon request (including gifs if needed and as time allows), note that the "geocolor" and "natural color" appear the most resource intensive. 

I'm providing a list of links to locations around the arctic using band I2 (my favorite), with the minimum number of frames (6), and as a still image.  My hope is that this'll be gentler on this with metered/throttled/slower connections.

These are not the maximum zoom, but can be zoomed in once more.

North Pole lower left, 60°W-30°E
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16692.4169921875&y=15199.47265625

North Pole upper left, 150°W-60°W
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16698.4169921875&y=16801.47265625

North Pole upper right, 120°E-150°W
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=15316.4169921875&y=16791.47265625

North Pole lower right, 120°E-30°E
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=15314.4169921875&y=15193.47265625

Kara Sea south
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13424.388671875&y=12085.361328125

Kara Sea north
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13230.388671875&y=13707.361328125

Laptev Sea/Lena River delta
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=11990.388671875&y=16609.361328125

Laptev Sea North
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13690.388671875&y=16701.361328125

East Siberian Sea west
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=12332.388671875&y=18799.361328125

East Siberian Sea east
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13088.388671875&y=19889.361328125

East Siberian Sea north
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13510.388671875&y=18583.361328125

Bering Sea
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13516.388671875&y=22929.361328125

Chukchi Sea south
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=14346.388671875&y=21249.361328125

Chukchi Sea north
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=13516.388671875&y=22929.361328125

Beaufort Sea west
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16126.388671875&y=20643.361328125

Beaufort Sea east
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16126.388671875&y=20643.361328125

Beaufort Sea north
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16344.388671875&y=19117.361328125

CAA - Amundsen Gulf/M'Clure Strait/Viscount Melville Sound
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=18660.388671875&y=20035.361328125

CAA - Prince of Wales Island/Resolute
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=19704.388671875&y=18613.361328125

CAA - Prince Gustav Adolph Sea/Byam Martin Channel/Peary Channel
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=18614.388671875&y=18465.361328125

Parry Channel east/Prince Regent inlet/Admiralty
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=20114.388671875&y=18195.361328125

Baffin Bay north
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=20272.388671875&y=16699.361328125

Baffin Bay south
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=21592.388671875&y=15855.361328125

Nares Strait/Lincoln Sea
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=18364.4453125&y=15877.3056640625

Fram Strait/Greenland Sea
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=17686.4453125&y=13599.3056640625

Svalbard
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=16480.4443359375&y=13325.3056640625

Franz Josef Land/Barents Sea
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i02&x=14846.4443359375&y=13313.3056640625

Greenland wide shot - band M8
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=2&im=6&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=20190804102542&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m08&x=20862.4453125&y=13657.22265625


22
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 04, 2019, 08:26:23 AM »
Total extent drop -93.6k, it is eating into the CAB now as well (-38.2k). Here is a diff with the previous day.

Bright red/blue: loss/gain of extent (crossing the 15% concentration limit). Light red/blue:  concentration change more than 7%. 

Click for the hi-res picture.

23
Arctic sea ice / Re: Freeform season chatter and light commentary
« on: July 31, 2019, 08:34:27 PM »
Is there any way to filter out messages based on poster and based on contained quotes?

Profile | Modify Profile | Edit Ignore List

I doubt that it filters quoted text, but I haven't tried it.

25
Arctic sea ice / Re: Freeform season chatter and light commentary
« on: July 27, 2019, 09:00:20 AM »
Rich, I am normally quite tolerant, and even more so towards new members. But I have been convinced there is a problem with some of your posts, and it's not about their content but about their tone. When you keep on arguing to the point of derailment due to overconfidence, when you relate to other posters as cult members, when you paint yourself as a martyr, and other examples too numerous to count, you piss people off and create dissension. I have no problem with claims of low or high momentum, this or that end if season forecast, and so on. In fact I often agree with your core content. But I still get pissed off, reading page after page of dissension which somehow involves you.

I think some humility would help fix things. It's not about you, it's about the science. Chill off. Don't take everything so personal. When you say something and are immediately told you are wrong by multiple posters, you probably are wrong. Take it to lightweight threads, go read source material (Wikipedia is often strong on the basic science but simple enough to.understand), rather than fight it out in high-rating threads. When given insults, ignore and move on, rather than insulting back. And avoid general attacks such as "cult" and so on. Humility and hard science are the proper tools here.

26
Arctic sea ice / Re: The 2019 melting season
« on: July 26, 2019, 05:23:18 PM »

 The M'Clure is terrible. … Banks and Eglinton … Prince of Wales Strait is a sickly gray; barring resupply from Viscount Melville Sound, that channel will be ice-free this summer, … 
Most of us don't know the Canadian Arctic like Ossifrage does.  Two maps on the Arctic Maps thread may assist:

27
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 25, 2019, 10:57:12 PM »
Just finished an exhausting forced march through this thread since my last visit. That's 40 minutes of my life I will never get back. When I would stumble upon a comment that actually had content, I struggled to connect with it due to the morass of detritus that preceded it.

28
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 25, 2019, 07:47:14 PM »
Regarding rebound years, we have seen the following feedback:

Low area -> warm ocean in the fall releasing heat and humidity -> enhanced snow fall that diminishes melting momentum next year and gives a chance for ice to grow again. This leads to a few year as of fluctuations until weather patterns are favorable again and a crash is again imminent. Parallel to that, we have the steady climb of the heat absorbed into the global system. The increase heat can lead to less snowfall and less of a rebound during the rebound years making the next crash come sooner. At some point you will be seeing a first year ice pack diminishing and increasing to its maximum in an annual cycle. I believe the first BOE event will be followed by a large rebound that will take a few years to resolve until the next bigger crash. And then we will be oscillating between BOE and no BOE, until the heat is enough and the number of days and weeks in BOE increase beyond a threshold. All and all we are talking for a few decades before we reach that point .. maybe 1 maybe 2. The system does not seem to have faster dynamic than this ( as observed in the last 20 years).

29
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 24, 2019, 08:28:16 PM »
Ken,

You missed the point. Read their own limitations statements.

I do use models. I am decidedly not a great fan of models of any kind. They always need to be sanity checked against reality. Models nearly always have embedded in them serious limitations that are often not fully recognized or described. Very often perceptual and belief systems biases result in unstated presumptions and assumptions that strongly affect or limit them.

And in this I am not specifically or even majorly focusing on climate models. Their limitations are greater than most. More I am referring to a huge array of models that I have personally worked with over the last 40 years. In my youth I trusted them far more than I should have. In a couple of cases that misplaced trust nearly got me killed. I developed a strong skepticism as a result. I still used models. They are incredibly valuable. However, I do not place faith in them.

Extrapolating models beyond their proven basis conditions is particularly dangerous. For climate that now is required if we are to have any guidance from them at all. That does not mean using them blindly without thoroughly and critically analyzing them and their origins. By that I mean especially looking for unstated unconscious biases and errors.

Any statements like “we must assume that...” are huge red flags. And I am not saying this happened here.

But so too are things like creating a linear model from chaotic data and then concluding based on that model that nonlinearities will not arise under radically changed conditions.

Sam

30
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 24, 2019, 05:09:28 PM »
Phil just posted this paper on the increased heat content of the halocline in the Beaufort Gyre.

https://advances.sciencemag.org/content/4/8/eaat6773

Implications and outlook
" The doubling of BG halocline heat content over the past three decades appears attributable to a warming of the source waters that ventilate the layer, where this warming is due to sea ice losses in the Chukchi Sea that leave the surface ocean more exposed to incoming solar radiation in summer. The effects of an efficient local ice-albedo feedback are thus not confined to the surface ocean/sea ice heat budget but, in addition, lead to increased heat accumulation in the ocean interior that has consequences far beyond the summer season. Strong stratification and weak mechanical mixing in the BG halocline ensure that significant summertime heat remains in the halocline through the winter.

With continued sea ice losses in the Chukchi Sea, additional heat may continue to be archived in the warm halocline. This underscores the far-reaching implications of changes to the dynamical ice-ocean system in the Chukchi Sea region. However, there is a limit to this: Once the source waters for the halocline become warm enough that their buoyancy is affected, ventilation can be shut off. Efficient summertime subduction relies on the lateral surface front in the NCS region between warm, salty water that is denser to the south and cooler, fresher water that is less dense to the north. For longer-duration solar warming (that is, longer-duration ice-free conditions in the region), SSTs on the south side of the front may become warm enough (around 13°C, under the assumption of a 1.5-month ice-free period dominated by solar absorption) that the lateral density gradient is eliminated [see (24)]. It remains to be seen how continued sea ice losses will fundamentally change the water column structure and dynamics of the Arctic halocline. In the coming years, however, excess BG halocline heat will give rise to enhanced upward heat fluxes year-round, creating compound effects on the system by slowing winter sea ice growth."

31
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 24, 2019, 03:41:13 AM »
The reduction of 45% by 2030 and carbon neutral by 2050 is to keep warming under 1.5C.  I agree that probably wont happen.

Here's what the IPCC stated about reductions needed to stay under 2C:

Quote
In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range). For limiting global warming to below 2°C11 CO2 emissions are projected to decline by about 25% by 2030 in most pathways (10–30% interquartile range) and reach net zero around 2070 (2065–2080 interquartile range). Non-CO2 emissions in pathways that limit global warming to 1.5°C show deep reductions that are similar to those in pathways limiting warming to 2°C. (high confidence) (Figure SPM.3a) {2.1, 2.3, Table 2.4}


Ken...you challenged someone for not reading the IPCC report that you linked to. Did you even read the quote you pulled from the report before you posted this comment? The bold underlined text has been highlighted by me.

Also please take a look at this linked chart...

https://ourworldindata.org/grapher/annual-co-emissions-by-region

...and explain to me where you think we will get a 11 billion ton reduction in annual CO2 emissions in the next decade in order to keep warming below 2C, given the current trends.

At best, emissions in 2030 will match emissions in 2019 and that is only if we start doing things we are not yet doing. We are not going to hold temp gains below 2C, not even close.

32
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 23, 2019, 11:45:18 PM »
This thread has taken one helluva nosedive recently.
It is the roar of frustration and fear, which I in every way understand, and which is in every way understandable.

I have great sympathy for Teapotty and Archimid. 

Any differences I have with them are nuance of detail, much like whether the curtains will burn before or after the windows blow out of the burning house we find ourselves in.

I don't discredit their feelings.  In fact, for the most part, I share them.

33
Arctic sea ice / Re: The 2019 melting season
« on: July 23, 2019, 04:51:04 PM »
So yep, i doubt that particular ESRL forecast like really very much. It's like saying "hey 24/7 sun still high enough for most of its energy to reach the surface - means almost nothing in an Arctic melting season". You know? Really hard to "buy", this sorta thing. Except if there is nearly no ice left there beforehand.

It is but one forecast and of course should not be taken as gospel. Worth reminding everyone that the first word in ESRL is Experimental (lol !)

Bring back the buoys I say and curse Trump for all his cutbacks.

At this time of year it was always a great daily joy to check the O buoy camera to see the condition of the ice first hand.  :(

34
Arctic sea ice / Favourite Floes - as long as it lasts
« on: July 19, 2019, 10:24:42 PM »
Having seen a number of incumbents advertise a series of single floe disintegrations over the years, I thought it might be better to sample all these interesting stories in one thread. At the end of the day,  someone will have the great fortune/luck of describing the last floe and it's demise.

Please feel free to copy or link to those stories created by A-Team and others here. It may eventually teach us a lesson or two about how it all happened.

Cheers P

35
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 15, 2019, 06:55:53 PM »
Quote
But they are better than nothing, you have to work with the tools you have got not the ones you would like, and the models show the same thing for 2020 2040 and 2060.

Let me be very clear about this. In the model that predicts a BOE by 2080, if you instantly remove the ice in 2020, 2040, or 2060 the ice immediately comes back. Well of course it does. The model is underestimating melt and/or overestimating freeze.

A wrong model is worse than nothing, if you make decisions according to the wrong model.

However, as the arctic keeps changing and showing scientist new secrets, I'm sure that better models will emerge.

Quote
You might want a newer source and better model, but basically tough: If it doesn't exist, then you are not going to get it. If there are two papers saying the same thing, then another paper is unlikely to be published unless it is saying something markedly different.

You don't think missing the first BOE by 4 decades (possibly more) is something markedly different?

Those model results are based on actual physics and include things often missing from the simplistic arguments about a BOE.  For example, the negative feedbacks, the depth of the central Arctic Ocean, and the fact that the gradual build up of the heat in the atmosphere mostly goes into the deep ocean, not the atmosphere or the ice.

Here's a good explanation of why there isn't expected to be a "tipping point" in the event of a BOE from a 2018 paper by Julienne Stroeve and Dirk Notz.

https://iopscience.iop.org/article/10.1088/1748-9326/aade56/meta

Quote
Changing state of Arctic sea ice across all seasons
Julienne Stroeve and Dirk Notz 2018 Environ. Res. Lett. 13 103001

Abstract
 

The decline in the floating sea ice cover in the Arctic is one of the most striking manifestations of climate change. In this review, we examine this ongoing loss of Arctic sea ice across all seasons. Our analysis is based on satellite retrievals, atmospheric reanalysis, climate-model simulations and a literature review. We find that relative to the 1981–2010 reference period, recent anomalies in spring and winter sea ice coverage have been more significant than any observed drop in summer sea ice extent (SIE) throughout the satellite period. For example, the SIE in May and November 2016 was almost four standard deviations below the reference SIE in these months. Decadal ice loss during winter months has accelerated from −2.4 %/decade from 1979 to 1999 to −3.4%/decade from 2000 onwards. We also examine regional ice loss and find that for any given region, the seasonal ice loss is larger the closer that region is to the seasonal outer edge of the ice cover. Finally, across all months, we identify a robust linear relationship between pan-Arctic SIE and total anthropogenic CO2 emissions. The annual cycle of Arctic sea ice loss per ton of CO2 emissions ranges from slightly above 1 m2 throughout winter to more than 3 m2 throughout summer. Based on a linear extrapolation of these trends, we find the Arctic Ocean will become sea-ice free throughout August and September for an additional 800 ± 300 Gt of CO2 emissions, while it becomes ice free from July to October for an additional 1400 ± 300 Gt of CO2 emissions.

Quote
4.2. Stability of the ice cover


In addition to changes in the external forcing and internal variability, a self-amplification of the ongoing ice-loss could in principle have contributed to the rapid ice loss in recent years. Such self-amplification is usually discussed in the context of so-called tipping points or nonlinear threshold, which are often defined as processes in the climate system that show substantial hysteresis in response to changed forcing.

The best known example for such possible hysteresis behavior is related to the ice-albedo feedback mechanism: a reduced ice cover in a given summer will cause increased absorption of solar radiation by the ocean, contributing to further reductions in the ice cover. Such positive feedback loop can cause the irreversible loss of Arctic sea ice in idealized studies based for example on energy-balance models (see review by North 1984), and have hence been suggested to possibly be relevant also for the real world.

However, an analysis of the existing observational record and a substantial number of respective modeling studies with complex ESMs all agree that such a 'tipping point' does not exist for the loss of Arctic summer sea ice. For example, Notz and Marotzke (2012) found a negative auto-correlation of the year-to-year changes in observed September SIE. Hence, whenever SIE was substantially reduced in a given summer, the next summer usually showed some recovery of the ice cover. This was further supported by Serreze and Stroeve (2015). Such behavior suggests that the sea-ice cover is at least currently in a stable region of the phase space, as otherwise one would then expect that any year with a really low ice coverage should be followed by a year with an even lower ice coverage, driven by the ice-albedo feedback mechanism. As shown by Tietsche et al (2011), the contrasting behavior of the real ice cover can be explained by compensating negative feedbacks that stabilize the ice cover despite the amplifying ice-albedo feedback. The most important of these stabilizing feedbacks relates to the fact that during winter the ocean very effectively releases heat from those areas that became ice free during summer, thus over-compensating for any extreme ice loss in a preceding summer. Ice that is formed later in the season also carries a thinner snow cover and can hence grow more effectively during winter (e.g., Notz 2009). Stroeve et al (2018) suggest, however, that this stabilizing feedback mechanism is becoming weaker and weaker as Arctic winters become warmer and warmer. Increased winter cloud cover after summer sea ice loss as found by Liu et al 2012 also weakens the stabilizing feedback, as it reduces the loss of heat from the ocean surface.

The apparent mismatch of observations and complex model studies on the one hand, which both show no emergent tipping-point behavior of the ice loss, and studies with idealized models, which show tipping-point behavior, was resolved in a dedicated study by Wagner and Eisenman (2015). They were able to extend simplified models until their behavior agreed with more complex models. In doing so, they found that both spatial communication through meridional heat transport and the annual cycle in solar radiation are important for stabilizing the ice cover's response to changes in the external forcing.

36

At this point I'm trying to keep it as simple as possible and isolate the variables. Perhaps it's incorrect, but I'm working with an assumption of 1 layer in 10m deep coastal water.

Sounds reasonable to me, as long as there's a little wind and/or waves.  But even this would be seasonally variable.  In freezing season, salt is excluded from the forming ice, and sinks to the bottom.  In melting season, melting ice releases fresh water, which floats above the saltier water below.  Still, in 10 meters of depth, it won't take much wind or waves to mix the whole column of water, once the surface ice is gone or pulverized.

We have very little data for depth/salinity/temperature plots on the Russian side of the arctic.  The few buoys we periodically discuss here all get placed on the US/Canadian side.

For the submerged permafrost, degradation will be slow, because heat from the ocean waters above hasn't a strong tendency to move down--heat rises.  At the bottom surface of the submerged permafrost geothermal heat is quite weak, as the permafrost layer is insulated from the geothermal heat by great depths of ancient sediment.

It works a little differently between land and marine permafrost degradation.  Freshwater lakes tend to have a temp of +4 degrees C at the bottom, because that's the temp at which fresh water is densest. These "thermokarst" lakes keep melting permafrost at their bottoms.  This is not the case for seawater, which is densest at about its freezing point. 

So melting of submerged permafrost will be very slow.  But I think it's effectively impossible for submerged permafrost to grow in depth, it can only thin and degrade over time.  Like, apparently, thousands of years.  Of course, the submerged permafrost has had something like 10k years to get along on the process since the last glacial maximum.

Shakhova and Semiletov have published voluminously on arctic permafrost.  I've only skimmed a few of their articles.  So if you want *real* expert information, I'd suggest perhaps starting here:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C21&q=Shakhova+Semiletov

37
I'm interested in exploring the relationship / correlation between water temp and depth.

Then you need to read up on salinity too. That is basically oceanography.

You might find Shakhova et al 2019 interesting.

Quote
In the ESAS, sea water is much warmer
than air (mean annual air temperature of −10 ◦C vs. mean annual sea water temperature of −1
◦C).
Consequently, the subsea permafrost has warmed by up to 17 ◦C during the last 12 kyrs [23,32]. It
has been suggested that the following factors determine the evolution of subsea permafrost after
inundation:

https://www.mdpi.com/2076-3263/9/6/251



38
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 11:53:31 PM »
Come on guys posts about the 384 hour GFS?

Also no year had "wall to wall" ridging.

It seems like quite a few active members here weren't around for 2012 or didnt follow the weather very closely.


2012 first two weeks of June  very sunny dipole for the most part.

Then a cloudy cool vortex took over from the 13/14th to the 26th.

Then the 27th of June saw a huge ridge blowing up over the CAB with major WAA from NA. 

A dipole anomaly ran the show from the 29th until the 10th.  The 11th was a transition day a strong vortex was expanding in size and strength while moving from the laptev region on the 11th towards the pole by the 12th and well into the CAB by the 13th and it expanded and rotated over 3/4th Arctic basin all the way until the 22nd/23rd.

Then things warmed up going into August.

Also the end of sunny skies in 2012 was the 11/12th of JULY.  LIKE THAT WAS IT.  IT WAS WALL TO WALL CLOUDS the rest of July.


The reason 2012 smashed the record was mostly because the lack of snow cover on the Arctic sea ice going into the melt season.

This is/wasa huge deal for any season to have major melt besides warmth.



I haven't seen the data for 2019 for what snow depth was at the end of May.

But I bet it was deeper than 2011 and 2012 in many areas.

However 2019 has made up for that with record level surface warmth.





Anyways please stop saying nonsense like:

It's getting cloudier so that gives 2012 an l the advantage.  Considering 2012 wasn't all that sunny before they 12th and after the 12th it was wall to wall clouds....


Also....

A more vortex laden pattern with a more neutral AO is giving 2012 an advantage is total nonsense.

I attached images below of 2012s turn in July. 


39
Arctic sea ice / Re: 2019 vs 2012
« on: July 09, 2019, 09:55:06 PM »

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.  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.
     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.       


40
Arctic sea ice / Re: Will the Bering Sea ever be the same again?
« on: July 09, 2019, 05:39:12 PM »
Not for a while, a geological 'while'

With the momentum in the earth system you can just skip that last part.

41
Arctic sea ice / Re: Will the Bering Sea ever be the same again?
« on: July 09, 2019, 05:17:46 PM »
Quote
Will the Bering Sea ever be the same again?
Not for a while, a geological 'while', unless human politics changes soon, a chameleon's 'soon'.

42
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 09, 2019, 04:48:59 PM »
NSIDC daily extent

43
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 03:53:58 PM »
The GFS is trending towards a cool Arctic and brutal heat over my head in the southeastern U.S.

There's no questioning Judah Cohen's interpretations of the model results, because they are correct, but the details make all the difference. The 384 hour GFS prog is very good for Arctic sea ice and very bad for me if I venture outside, but the GFS model is pretty bad at predicting weather over a week out.

If the GFS 384 hour prog verifies 2012 will likely take a solid lead over 2019, but I doubt the air over this Arctic will be as cool as the forecast output below.

If there is one thing I'd bet my mortgage on not happening it's whatever the the GFS is showing at hour 384...

44
Indian Ocean Causes Drought and Heatwaves in South America
https://phys.org/news/2019-07-indian-ocean-drought-heatwaves-south.html

New research has found the record-breaking South American drought of 2013/14 with its succession of heatwaves and long lasting marine heatwave had its origins in a climate event half a world away—over the Indian Ocean.



It all started with strong atmospheric convection over the Indian Ocean that generated a powerful planetary wave that travelled across the South Pacific to the South Atlantic where it displaced the normal atmospheric circulation over South America.

"The atmospheric wave produced a large area of high pressure, known as a blocking high, that stalled off the east coast of Brazil," said lead author Dr. Regina Rodrigues.

"The impacts of the drought that followed were immense and prolonged, leading to a tripling of dengue fever cases, water shortages in São Paulo, and reduced coffee production that led to global shortages and worldwide price increases."

That impact wasn't just felt on land as the high-pressure system stalled over the ocean.

"The result of this blocking high was an unprecedented marine heatwave that amplified the unusual atmospheric conditions and likely had an impact on local fisheries in the region."



... The 2013/14 South American drought and marine heatwave is the latest climate case study to show how distant events in one region can have major climate impacts on the other side of the world.

"Researchers found that Australia's 2011 Ningaloo Nino in the Indian Ocean, which completely decimated coastal ecosystems and impacted fisheries, was caused by a La Niña event in the tropical Pacific," said Australian co-author Dr. Alex Sen Gupta.

"Here we have yet another example of how interconnected our world is.

Regina R. Rodrigues, et.al., Common cause for severe droughts in South America and marine heatwaves in the South Atlantic, Nature Geoscience (2019).

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

Summer Eurasian Nonuniform Warming Found Related to the Atlantic Multidecadal Oscillation
https://phys.org/news/2019-07-summer-eurasian-nonuniform-atlantic-multidecadal.html



"Previous studies indicate the Eurasian nonuniform warming since the mid-1990s may be related with the phase shift of the AMO, and we validate this point by using ensemble experiments with three AGCMs [atmospheric general circulation models]," the lead author says. "The overall consistency among the three AGCMs illustrates the robustness of the AMO's influence, although the models are not the most recent updated versions," she adds.

The authors diagnose the underlying mechanism of the AMO's influence on the Eurasian nonuniform warming from the perspective that the boundary forcing modulates the intrinsic atmospheric variability. The results highlight the role of the Silk Road Pattern.

"The AMO-related tropical diabatic heating anomaly excites the Silk Road wave-train over Eurasia with positive geopotential height and anticyclonic circulation anomalies over Europe-West Asia and Northeast Asia, but negative geopotential height and cyclonic circulation over Central Asia. Such opposite circulations lead to opposite changes in temperature advection, precipitation, cloud cover and solar radiation. When these effects overlap the signals of global warming, it causes amplified warming," the authors explain.

Xueqian Sun et al, Simulated Influence of the Atlantic Multidecadal Oscillation on Summer Eurasian Nonuniform Warming since the Mid-1990s, Advances in Atmospheric Sciences (2019)

45
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 07:04:54 PM »
Climate activists in Cologne.

No, not off topic. They are literally standing on 2019 melting ice!


46
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 05:32:32 PM »
The northern tip of Greenland (on the right)

47
Since the GAC has been a topic today, I'm going to pop up a question that's been bothering me for ages.

The GAC formed over Siberia and moved over to the Arctic and intensified. As someone only slightly acquainted with tropical cyclone formation I'm curious how does that happen exactly? How does an extratropical cyclone strengthen over the arctic sea? With all the heat in the arctic going into the melting ice and SSTs as a result being quite steady and low what does it feed on? Or do they just run that much colder that some open sea having gained even a little bit of dew point is enough?

Also are there some features to look for that might favour their generation and intensification like we have with tropical cyclones?

This is a valid question for me as well. The initial, moderate storms come from the periphery both in 2012 (Siberia) and 2016 (Kara),  and then have a surge in strength as they locate at the center in the Arctic. 2016 GAC restrengthens by merging with other lows several times. I don't know, in both cases a disruption of the normal atmosphere due to the anomalous warmth of the Arctic regions might have played a role, but I am not expert on that. 2016 was also a very warm year even when it didn't show on top of the ice until July.

48
Arctic sea ice / Poll: ASI JAXA Minimum Extent range of possibilities
« on: July 07, 2019, 04:06:03 PM »
All 'guess the minimum' polls to-date have been to guess the minimum (or maximum) of something.  Here, we are to exclude the ranges (bins) we consider not possible this year.  There are 12 bins, and you can vote 'against' up to 11 bins.

For example, if you think the Arctic Sea Ice Extent (ASIE) will be 4.0 million km^2 [= km2] at minimum, you'll accept it might be a little more or a little less, but definitely not a lot more or less, definitely not a blue ocean event (BOE, for this poll's purpose = under 1m km2), therefore you will select (vote for) [something like] the top 3 bins (5.0 and up) and the bottom 4 bins (2.5 and under, leaving 4 bins you consider possible (2.5 - 5.0).  The more confident you are, the more bins you will select.  E.g., if you 'know' there will be a BOE, you'll select the top 10 bins.

50
Arctic sea ice / Re: Glossary ... for newbies and others
« on: July 07, 2019, 04:16:25 AM »
FSW from here
Fsw = Daily average solar radiation in W/m^2.

FSW = the solar insolation at the top of the atmosphere  [note:  it is "F" sub "SW" ]
from here - used 17 times in that paper  (This paper referenced in 2017 by rboyd)

and in context: 
Quote
The annual-mean incident solar radiation at the top of the atmosphere (FSW) varies significantly over the Arctic Ocean latitudes ranging from about 210 W m-2 at 65oN (roughly the latitude of Bering Strait) to less than 175 W m-2 at the North Pole.

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