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Messages - jdallen

Pages: [1] 2
1
Arctic sea ice / Re: The 2019 melting season
« on: May 03, 2019, 06:33:37 AM »
<snippage>
Persistent northerlies has meant the pack is pushed against the north coast of island of Spizbergen - something that hasnt happened since July 2017.
It appears Fram export is ramping up in tandem with this.  Just the last few days it appears the ice has been accelerating through it.  The northerlies no doubt are contributing to this.

Velocities appear to be approaching 1-1.5KPH.  At current concentrations, that's upwards of 10,000KM2 a day of the thickest ice in the region past the point of no return.

2
 Can we please stop this nonsense and close the thread?


 :o

3
Arctic sea ice / Re: The 2019 melting season
« on: April 26, 2019, 06:36:12 AM »
something tells me we're in for a nasty drop from day 2-5
Actually, I'm expecting extent to stay relatively flat, possibly even expand, but concentration to drop.  Basically, the mostly the same ice except spread over a wider area.

Still not good for what's coming.

4
Arctic sea ice / Re: The 2019 melting season
« on: April 25, 2019, 06:34:17 AM »
Where did you read this?  Is there a website that tracks albedo?
One of our users, Tealight has built a whole slew of marvelous tools to follow Albedo.

https://forum.arctic-sea-ice.net/index.php/topic,1749.0.html

5
Arctic sea ice / Re: "Stupid" Questions :o
« on: April 11, 2019, 07:22:28 PM »
Does anyone know what causes these clockwise dancing foes?

Doesn't look like it's a gyre, or?
>:(
Looks to me like its either current or tidally driven.

6
Arctic sea ice / Re: Are 3 dimensions better than 2?
« on: April 08, 2019, 05:38:32 PM »
However, they emphasize the importance of ice cover over other attributes in the total system.

No they don't. At the risk of repeating myself:

https://nsidc.org/cryosphere/icelights/2011/08/getting-beneath-ice

Quote
NSIDC reports ice extent, a two-dimensional measure of the Arctic Ocean’s ice cover. But sea ice extent tells only part of the story: sea ice is not all flat like a sheet of paper....

Scientists want to know not just how far the ice extends, but also how deep and thick it is, because thinner ice is more vulnerable to summer melt.

Exactly what are you gleaning out of this report to support your claims, besdeds they are trying to measure thickness more accuratey?
... that they consider thickness/volume a key metric for understanding Arctic system behavior....

7
Arctic sea ice / Re: Are 3 dimensions better than 2?
« on: April 06, 2019, 08:07:31 PM »
What is 7 million km2 at 6 cm thick?

Impossible.

Straw man question. You will never have 7 million KM2 at 6CM thick, not even as an average.

In fact I consider it dubious to call anything less than 15CM thick anything other than slush.

8
Arctic sea ice / Re: Are 3 dimensions better than 2?
« on: April 05, 2019, 11:09:01 PM »
Is it real world when all the volume numbers are models?

Models are not real. The observations feed into the models are though.
Models are estimates derived from the best available data, complete with confidence levels. Even if imprecise, as year over year the use the same inputs and rules, They can be used to identify trends and changes in scale.

9
Arctic sea ice / Re: The 2019 melting season
« on: April 05, 2019, 02:40:41 AM »
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort.
While I tend to agree with the first part, I would say that melt ponds in the beaufort are working towards investigating the processes involved in the possibility of forming. ;)
<Laughter>
I concur.  April melt ponds, no.  May meltponds, a distinct and unpleasant possibility.

Also in play - increased and earlier snow melt outflow from peri-arctic drainages, which I think may further accelerate the melt.  Anyone have eyeballs on what the Mackenzie is doing currently, for example?

10
Arctic sea ice / Re: Svalbard
« on: March 22, 2019, 09:25:50 PM »
Looks like the right place to me.

11
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 15, 2019, 10:01:21 PM »
<snippage>
However ... in general, I find myself wondering many, many, many times while reading (candidly, mostly comment posts, not the data posts) who's "ROOTING" for LESS ice...?
<snippage>
Nothing like that.  To an individual I'm certain we would be delighted if climate change were proven to be a hoax by everything going back to status quo of the 19 century.

But you see, it won't.

So the hope is, (at least from my stand point) is for there to be a sudden, irrefutable, dramatic climate event that forces world leadership to act.  To that end, a more dramatic demise of the ice is desirable from my stand point.

So again, "rooting" is the wrong word.  "Hoping" for an event that galvanizes society would be correct.

12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 05, 2019, 08:19:45 AM »
February 25 - March 4.
I find the early retreat in the Chukchi is more worrisome than what's happened in the Bering.

13
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 05, 2019, 07:19:08 AM »
In a similar vein, extent may be increasing in the Barents as ice is blown into it, but when it looks like this, it isn't going to persist very long once the tip-over in insolation occurs.

14
Arctic sea ice / Re: The 2019 Melting Season
« on: March 02, 2019, 12:11:43 AM »
We have had bigger rebounds recently, but not by much.  If today shows another drop that may be it.

The only place I can see actually changing that I'd the Barents, but there the ice is fighting the highest imported heat in our history.

15
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 01, 2019, 08:33:06 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.
 
February 28th, 2019:
     13,914,006 km2, a drop of -44,911 km2.
     2019 is now 5th lowest on record.
     Six consecutive drops. Total drop from Feb 22nd max: -280,554 km2.

There have been late season swings greater than 280K, but not by much, and not many.

If we have more declines, that may be it.

16
Arctic sea ice / Re: What's new in the Arctic ?
« on: December 14, 2018, 07:31:16 PM »
Concur with Juan.

Francis has been ahead of the curve describing some of the phenomena we see currently.

There is nothing ulterior in her communicating about it, no is it alarmist.

17
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: December 09, 2018, 01:56:15 AM »
I've been brooding over PIOMAS volume data the last 3 days, following some discussion elsewhere about trends vs "weather" and the kind.

I'm staring here as I write at 4 graphs I derived from the PIOMAS data downloaded from the U.of Washington Polar Science center.  I'm pondering what it implies about past changes in the Arctic and what import it has for the future.

Let me back up for a moment and describe what I've done first, and why.

There's been a lot of discussion on the Arctic forums recently around three dimensions we use to evaluate Arctic system health.

In our discussions and arguments we've wrestled with the reality that two of those measures - extent and area, particularly as they appear at the end of melt season - have become increasingly difficult to evaluate to make a skillful determination of how the Arctic will look in a few years. Our discussion has shifted and expanded now to where over the last two years there has been much more tracking and examination of the annual refreeze.  This has given us some hints and generated quite a few more questions.

Roll back to what I'm doing now.  I'm using PIOMAS daily volume data going back to 1979 (http://psc.apl.uw.edu/data/)

My analysis is more empirical than theoretical.  At this moment I'm less interested in prediction than I am the data set.  I have a particular interest in volume as well. Unlike extent and area, it represents a far better proxy for key forces at work in the Arctic - heat exchange and total system enthalpy.

My second purpose is contrast volume changes with changes that have taken place during the time period in question and see if a pattern appears which follows or is affected by them.

Methods:

Simply digesting a raw and fairly substantial pile of data is unlikely to produce anything useful.  However, I don't want to fall into the trap of over-analyzing the information - while it is good to reduce "noise", over-processing values can remove meaningful signals it contains.  My approach to this is three fold.

1) Create a sample average from a meaningful but more controllable time frame.

Most analysis of this data has been around extreme endpoints in annual variation - the annual maximum extent/area/volume and corresponding minimum - which land on arbitrary dates and are very narrow samples.  For my work here, I've picked to arbitrary but significant dates March 21 (Day 80/81 of each year) and September 21 (Day 260/262).  I then averaged the daily volume for a time frame window which extends from two weeks before until two weeks after those dates to get what I call "Vernal" and "Autumnal" volume numbers for those dates.

My logic in doing this is this: Rather than use a metric which is volatile and fundamentally disconnected from other forces in play at the time they take place (annual minimum/maximum), I wanted to anchor the analysis to two specific points in them where we know predictable and measurable changes are taking place (the Spring and Fall equinoxes).  Further, to make the new metric sensitive to conditions during the specific year and season, rather than simply pluck out one number, an average over a near-term time frame would better incorporate and smooth other signals from forces in play at the time.

In addition to these two numbers, I also created a baseline value for tracking behavior on a broader time scale.  In this case, I created an annual average for each year, summarizing all volume measurements from January 1 to December 31 for each year in question.

2) Create a derivative average which further smooths the Vernal and Autumnal numbers over a wider time frame. 

In this case, I created a second data set from my spring and fall averages, starting with 1983, which is a simple 5 year running average of those numbers.  The goal here is to round off peaks and valleys without losing all of the signal they contain, and hopefully permit underlying trends to be more visible, and more importantly, better identify transitions in system behavior.

3) Create a third derivative/index to show system volatility.

At the start, these were actually the numbers I was most interested in. We've discussed this some on the forums, but the summary of my thought here is, this, and also may qualify as a hypothesis:  As the Arctic as a system approaches behavioral limits, the volatility of the system - the relative change against base values - will increase.

Again keeping it simple, I created three values for each year in question.  These were (a) The absolute difference between Vernal and Autumnal values (b) the Percent that value represented of the Vernal volume and (c) the Percent that value represented of the Annual volume as derived in (1) above.  I did this for both the raw and 5 year running averages of Vernal, Autumnal and Annual values.

Note: all values I used were rounded up to three decimals. I figured the significance of fractional cubic KM of ice were meaningless based on the confidence of the measurements.

Findings:

From raw data and graphic analysis by Jim Pettit, Zach Labe and many others it's already clear that sea ice volume has been declining steadily over the time period in question.  What isn't necessarily clear is the nuances of how those changes have taken place.

Both the smooth and averaged data clearly shows this trend. No surprises (nor were any expected).

However, annual seasonal loss has shown only a very modest increase - less than 10% over all - with an average of 14.242K KM3, median of 14.034K KM3 and deviation of 1.164K KM3.  Breaking the loss dataset in half shows the 2nd half loss rate only increasing by about 1000KM3, and 2nd half loss volatility actually declined slightly. The 5 year running averages are correspondingly closer.  This suggests strongly that large year to year variations in melt are not significant contributors to the reduction in volume over the period measured.

The first think that jumped out at me in particular in the averaged data, is I think I'm seeing two historical locations where I think there's a signal identifying a fundamental change in how the system behaves.  The first is in the 1990-1994 time frame. There I think spring, fall and yearly average graphs start a break in slope, falling into the glide path that takes us down hill to where we are now.  I'm not sure what the specific conditions were at the time, or, considering hysteresis, how far back we need to look for the trigger, but it strikes me that is a specific place in time and space we can point at where the system signals a change has taken place.

The second was the 2010-2013 time frame.  in that range all three measures - Annual average, spring and fall - flatten out.  As another interesting and possibly key item, annual loss intersects and then starts to follow the annual average curve.  I'm not sure what this means yet, but it sure looks like a strong signal.  Also, while the three major curves flatten, the *vernal* curve is still trending down.  I think the running 5 year equinox graph shows this the best.

My general take away - I think the graphs support another of my thoughts - that as the total energy available to the system increases (reduced ice), the overall volatility of its metrics will increase - especially area and extent - which actually are more derivative of this than volume.

I'll be interested to hear what other folks think.  If someone can point me in the right direction, I'll post the spreadsheet with my raw numbers someplace for people to tear apart.

 (P.S. - the average volume will be off a bit for 2018 as we haven't finished the year.  That said, we are far enough along it that the relative change is small enough to be negligible to my analysis.)

18
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 28, 2018, 06:51:36 AM »
There is - what is, and
there is - what may be.
Indeed, and then, there is - what may likely be.

GFS, CMC, EURO all show same thing.  ;)
Still way to far out.  There were lots of forecasts last fall that suggested all kinds of dire stuff - worse for ice creation than 2016 - but which moderated dramatically when we got closer to the 4 day window.  What you are seeing at day 8 is still so general and has such high probability of error that it has little utility beyond tweaking our curiosity.
All ensembles are also in agreement. This is partially due to the recurving WPAC storm / typhoon which becomes a major low near AK. I think this leads to a higher probability forecast vs. normal. But if I am wrong, feel free to throw this in my face come D8 (I will post verification then, myself!).
What you are doing is effectively rolling dice.  Like in craps, you eventually might make your point, but the advantage remains with the house. Like in craps, the success of your predictions when they happen are overwhelmingly luck rather than skill.

19
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: November 15, 2018, 05:30:49 PM »
Not sure what to make of this all, but the ice gain over the past month is the second highest in the satellite history, with the gain over the past two weeks being the highest.  Based on current and forecast temperatures I expect this to continue in the short term.

Klondike Kat's statement in numbers:

2018 had the 2nd highest extent gain from November 1st to November 14th in satellite history. That's an impressive recovery from the very slow start of this year's freezing season.
The closer an oscillating system gets to it's boundary conditions, the greater its volatility.  That's my take away.

20
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 06, 2018, 01:12:53 AM »
This is losing its utility.

and the polar vortex isn't a ground level feature.  not all cold is a polar vortex...
*Thank you* sark.

What is happening looks far more like matching breakouts over the Canadian Shield and trans Ural Siberia, along with intrusions of heat across The Bering and Barents/Greenland seas.

21
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 05, 2018, 03:47:25 PM »
...
The polar vortex has plunged into Canada, and by D5, it should be sitting over Hudson Bay.
...

Am I looking at the wrong thing?  The polar vortex?  Looks like its over Svalbard on Day 5 and the rest of the forecast has it settling down over Greenland after the wave of Oscar smacks it around a bit.

https://imgur.com/a/Z1L8w4T
gif of 11 day forecast shows it centering on the other side of Greenland from Hudson Bay.  Hudson Bay?  Am I looking at the polar vortex temperature and heights at 10mb or have I got it wrong?
GFS about 3 days out is showing blooms of heat rolling into the Arctic from both sides of the basin, and an outbreak of cold air across the Canadian shield just east of the Rockies, and a matching breakout of cold air (it appears) into central Siberia across the eastern Barents.

Heat blowing in from the oceans on either side squeezing the cold air out of the arctic the way tooth paste would blow out if you dropped it on the floor and stepped on it hard enough.

22
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 15, 2018, 03:53:15 PM »
I mean if that is the case, on the one hand, it is good news, cause lot of stored heat should go away under this "cold spell", but on the other hand it is really bad news, cause if the area would have been already ice covered it  could have used these weather conditions to thicken a little bit, cause we know how unstable polar vortex is lately, and it is only a matter of time before there is another "attack" from the south. But now even if the ice forms there at the end of this period(7-10days), and that is a big IF, it will be very thin, and very vulnerable if there is another warm air advection from lower latitudes end of Oct or even beginning of Nov.
Found this paper, may be useful in understanding the dynamics.  It's going to take a while for me to digest it; the calculus will be a challenge for me.  However, I'm able glean some useful tidbits from it about the general dynamics which apply:

https://www.hindawi.com/journals/ijas/2013/503727/

My take on things - making the heat more accessible is good, but there is a fixed limit on how fast that heat can leave the atmosphere. 

A metaphor if you will, our bucket has a hole that only lets water out just so fast.  If we pour more water into it, we still have the same aperture.  Pressure may cause a little more to flow out, but if that doesn't keep up with what we add, the water level in the bucket will still rise.

23
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 14, 2018, 05:56:24 AM »
The 365-day anomaly is rather interesting too in that there seems to be a band somewhat colder than historical just below the very warm Arctic. WACCy weather.  (Given the cold spots in the North Atlantic and in the South Pacific, is there any chance this is at least in part a latitude thing?)
I think what you are seeing is evidence of the breakdown of the polar cell, and the export of cold air it previously sequestered breaking out into lower latitudes, while being replaced by much warmer and moister inflows.

That describes part of the process.  here's an interesting article with some more detail.

<snippage>
The thing is, it's not really colder continents - its cold exported from the Arctic - and the increased snowfall is actually an artifact of *more* rather than less heat.  You can't have the increased snowfall without increased water vapor, and you can't have increased water vapor without increased heat. Pure physical chemistry, nothing exotic here.

24
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 12, 2018, 08:06:52 PM »
If this becomes true, it should be named "Abrupt Climate Change" for Bering and Chukchi Sea.
Very much so. Even now, even with shorter days, because of the lack of ice cover both of those seas are still picking up isolation and downwelling longwave radiation.

That radiation is not enough to stop the refreeze, but is a very substantial increase to the seas annual heat capture.

Meanwhile, outgoing heat out of the atmosphere is limited by physics and *can't* increase except in smaller increments determined by temperatures in the upper atmosphere.  As a metaphor, we are increasing the flow of water into a tub without changing the size of the drain.

Further,  that feedback is self reinforcing (to a limit);  increases in energy capture will tend to increase the rate at which it is captured, year over year.  I have no timeframe to suggest, but this is a disturbing trend.

25
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: August 31, 2018, 10:36:53 PM »
OK, first off, there has always been enough heat in the Arctic ocean to melt the ice, and keep it of, even during winter.  What saves the ices is the fact the heat is isolated below thermoclines and haloclines.

What I consider the real take-away of the paper is that it confirms my sense of how the system is changing, and how a BOE will eventually take place.

That enthalpy has doubled does not instantly mean the event is imminent.  This process is more like something out of Poe's "Pit and the Pendulum".

Our swinging blade - "pendulum" is the annual swing in insolation and heat transported into the Arctic.  Each swing varies slightly from the last, but falls predictably within a given envelope which encompasses the observed range annual heat uptake; heat uptake which is reflected in a combination of SST's and ice coverage.  Some years are 2012.  Others are 2013.   But, each year the heat is enough to melt between 16,000 and 20,000+ KM3 of ice.  (it used to be ~15-18, but over the last 20 or so Arctic Amplification has pushed the number up - see Jim Pettit's graphs).

Like Poe's "Pendulum" that swing cuts a little more deeply each swing because of increased available heat, but even with that the process of it finally whittling down the Arctic pack to a BOE will be very slow - like centuries - unless it gets help.

So our heat in the water is the wildcard that will accelerate that.  Unlike Poe's "pit", where the table our victim - the ice - is strapped to is fixed to the floor, the Arctic's is "moveable".  Namely this - that increasing enthalpy effectively raises the surface under the blade, making increasing areas of ice vulnerable to full melt out.  The practical way it performs this is by limiting how much ice can form, and how fast, rather than melting the ice directly.

So far we've seen this play out in the Barents and Greenland seas, neither of which typically fully melted out in the past, but now do.

I think this will become more apparent in the Chukchi and the Bering, and to a lesser degree the Kara.  Eventually it will be apparent in the Laptev, Beaufort and lagging behind those, the ESS.

I think reduced ice creation over time in these seas will eventually, over a much shorter timescale make the entire arctic vulnerable to a BOE happening through completely mundane seasonal variation in captured heat.

I will start expecting it imminently when the winter max volume drops under 20,000KM3.  When we hit that threshold, I think we will have a 1 in 10 chance that year of a BOE with relatively normal melt.  When the max drops below 19,000KM3, I think it will rise to a 1 in 4 chance.  At 18,000KM3 I think it will be 1 in 2.

So that's what I'll be watching for - decreasing end of freeze season volume.

As a last comment, I'll add that increasing ocean heat has a strong self-reinforcing feedback attached to it.  As we lose ice off of the peripheral seas, we will greatly increase heat uptake because of decreased albedo.  There are other factors here which are self-reinforcing, but the key take away is the warmer the water gets, the greater potential exists for increased heat capture.

26
Arctic sea ice / Re: The 2018 melting season
« on: August 27, 2018, 06:12:12 PM »
Are you quite sure about that? I agree that the claims on the "Image of the day" thread were overblown, but have you examined all the evidence carefully?
I am 100% sure, that the Ward Hunt Ice Shelf was not "obliterated" and has not "disintegrated" in the last view days. That was the claim. And calling it "overblown" doesn't make it better. I, and others, have shown you satellite image comparisons with previous years or current SAR images indicating nothing of that sort.
Look, I already apologized for and retracted my 'obliterated'  comment  in 'Images', but as discussion is spilling over here, I must put on a hair shirt and apologize for my error here again as well.  In that *particular* thread ('Images'), I treat less seriously and do not check as closely as posts elsewhere.

It is obvious you do not find that satisfactory, for which again, I apologise for offending you.

I am smart enough to be terrified by what is happening, and overwhelmed with my decreasing ability to have any influence on outcomes, and damn near clinically depressed over the staggaring toll of life coming changes will cost.  It leads me to occasional hyperbole.

I will try to do better in the future.

Please don't belabor the forum or this tired, depressed, frightened, old man over a minor error in judgement.

Please just point out the mistake without rancor and let us move on.

27
Arctic sea ice / Re: Arctic Image of the Day
« on: August 26, 2018, 03:27:44 AM »
Ward Hunt Ice Shelf on Ellsemere Island has collapsed in last few days
Obliterated may be a better description.

28
Policy and solutions / Re: Policy & Solutions
« on: August 17, 2018, 07:54:50 PM »

Quote
May I suggest taking the discussion off this "Policy and Solutions" thread within the "Arctic sea ice" section of the forum, and taking it to the "Policy and Solutions" section of the forum?  As Bruce requested.

This kind of misclassification of discussions bugs Neven, and we should respect the structure he has built here.

I didn't realize it couldn't be a matter of policy and solutions the amount of aerosols in the atmosphere...oh the misclassification...either you or I have  inhaled too many "aerosols"?

I gather you don't understand the structure of this forum.  Eco-Author created this thread in the wrong place.  There's a whole section for Policy and Solutions.  This thread is in the section for discussions of arctic sea ice  in particular.  Discussions such as this belong in a place like here:
https://forum.arctic-sea-ice.net/index.php/topic,2378.0.html

To drop random, unrelated commentary into well-organized threads is disrespectful to Neven's work and the whole community.

So the entire thread is not germane, and therefore my contribution is bad. Oh okay, I get it...

"How dare you post anything in this thread. The whole thing is inherently off topic."

Orwellian.
Just Chill, please.

Structure and purpose is not the same as suppression.  It's like paint stripes on highways and traffic signs.  Nothing is preventing you from travelling somewhere, we just don't want people randomly careening around disrupting other traffic.

Your comments aren't any more important than anyone elses.

29
Arctic sea ice / Re: The 2018 melting season
« on: August 12, 2018, 07:33:58 PM »
The amount of smoke is an indicator that the incoming airmass is very warm.

Do you have any evidence backing up the claim that "amount of smoke" means "very warm" airmass?

Of course not and smoke in the air from fires has no bearing on the warmth of the air.
Actually, it can.

https://www.thehindu.com/sci-tech/energy-and-environment/IIT-team-tracks-brown-carbon’s-effect-on-atmospheric-warming/article16703349.ece

Among other effects, it increases capture of UV which can heat the upper and mid atmosphere.

Not certain exactly how this affects melting but unlikely the effect is good. The effect is likely more pronounced off peak insolation.

30
Arctic sea ice / Re: The 2018 melting season
« on: August 12, 2018, 07:23:32 PM »
The amount of smoke is an indicator that the incoming airmass is very warm.

Do you have any evidence backing up the claim that "amount of smoke" means "very warm" airmass?
He may extrapolation from research like this:

 https://www.nature.com/articles/ngeo2960

31
Arctic sea ice / Re: The 2018 melting season
« on: August 06, 2018, 07:55:28 AM »
The peak that is shown on nullschool is almost 19C, 18.8C. What did Polarstern find?

https://www.sailwx.info/shiptrack/shipposition.phtml?call=DBLK

I don't think they went near the hot spot though.

*My* understanding is, they are both persistent upwellings from the Norwegian current when it hits the shelves around Svalbard.

NOAA map:

http://polar.ncep.noaa.gov/sst/ophi/color_newdisp_sst_north_pole_stereo_ophi0.png

32
Arctic sea ice / Re: The 2018 melting season
« on: August 03, 2018, 04:41:42 AM »
Shouldn't we be looking at the Hudson bay to go blue ocean year-long, long before the CAB does?!! 
Actually, counter intuitively, the greater probability is that it will continue to freeze after the CAB becomes "ice free" - less than 1 million KM2 of ice in winter.

The reason for this is cold continents/warm ocean.  Heat lost from land during low insolation will permit temperatures to drop far further than they will over the ocean, and by extension will tend to cool Hudson Bay as it is pretty much completely land locked.

33
Arctic sea ice / Re: The 2018 melting season
« on: July 30, 2018, 02:57:42 AM »
Yes I'm cherry picking but the gfs after the initial thrust of heat reforms a Siberian positive dipole.


This would be a perfect storm of events to cripple the laptev/CAB Atlantic front and finish the ESS off.
Just the high pressure by itself *without* a dipole is bad enough.  Between bottom melt and Insolation that's enough melt potential to strip 4-8CM/day off of existing ice, much of which is under 1M thick at the moment.

As I said earlier, based on what happened in the Kara, without optimal melt conditions, I'd expect the Chukchi to be ice-free, and very large swaths of the Beaufort, ESS and Laptev to be gone by the 3rd week of August.

34
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 30, 2018, 02:49:31 AM »
but until we see year-round ice-free arctic it will take centuries

I very much doubt about that plural.

in fact i believe that as long as this planet is supporting life, means temps are withing a range that allows for life and as long as there will be 5-6 months wihout sunshine, that we NEVER shall see year round ice-free arctic. <snippage>

Sorry to disabuse you, but we have geological evidence of exactly that - year round ice free Arctic - in the Pliocene - 3.7-2.2 MYBP. - under current atmospheric conditions.

https://www.scientificamerican.com/article/ice-free-arctic-in-pliocene-last-time-co2-levels-above-400ppm/

35
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: July 30, 2018, 01:28:35 AM »
I agree with Wherestheice.

Based on current volume trends -
1st completely ice free September Arctic Ocean 2022-2023 +/- 2
1st completely ice free year-round Arctic Ocean 2035-2050
1st I’ve free Greenland & northern hemisphere 100-250 years after that
Maybe sooner - depending on feedbacks
<snippage>
I think 2022-2023 is still early.  I'm putting thinking a sub-1 million KM2 September extent won't arrive until 2030 +/- a couple.

I don't think we'll see a year round ice free Arctic for at least a couple of centuries.  As long as there's 3 million+ KM3 of ice sitting on Greenland, combined with "cold continents"  I think most of the CAB will refreeze annually.

36
Arctic sea ice / Re: The 2018 melting season
« on: July 27, 2018, 06:07:34 PM »
I am as surprised as everyone else by the quick deterioration of the ice. ...
We've had hints.  Thinking back to the refreeze, the regions now disintegrating were late to freeze, and suffered heavily from persistent imports of heat through the Bering.  This was reflected in some of the thickness maps, but others consistently reported that the ice was probably a meter or more thicker than it actually was.

Roll forward to today.  Speaking in approximations, in recent years (2015 to present) volume at peak is running around 21,000 KM3 at max.  If you take the most recent maximum extent - about 14,000,000 KM2, we end up with an average ice thickness of about 1.5 meters.

Looking earlier - here I'm thinking of the old regime - 1980-89, the extent isn't particularly greater - only about 16,000,000 KM2, but typical average volume is much higher - on the order of 31,000 KM3, which gives us at that time a typical average thickness of around 1.93 - call it almost 2 meters.

The difference between the two - 50 centimeters - is very key, because the drop in thickness and volume means that we've passed a key threshold:  the typical energy taken up during the melt season in the Arctic is almost enough to melt out all volume.  The number here, approximating from Jim Pettit's graphs examining typical volume lost during the melt season, divided by max area works out to be about 1.3 meters of melt.

Obviously that melt isn't distributed evenly, nor is ice thickness.  However, it does mean that regions which do not pass that 1.3 meter thickness during the refreeze are now at serious risk.  It will take extraordinarily favorable conditions for ice retention to prevent an *average* melt from melting out the areas where this is true.

I think that's what we are seeing here, and elsewhere, such as the interior of the CAB where we've been having surprising losses in area.  Interstitial ice formed in leads during the season which did not have time to thicken sufficiently past that 1.3 meter threshold is disappearing.

We are definitely in a new regime.

37
Arctic sea ice / Re: The 2018 melting season
« on: July 18, 2018, 04:58:28 PM »
Can anyone explain me how it is possibble that the past 3 winters were the warmest "ever" in the Arctic and yet summers are not much to talk about. Where does the extra heat from winter go? Why does it not show up in big extent losses later on?
Where the extra heat in winter goes is out of the atmosphere, replacing heat that would have come out of the Arctic Ocean.

The result is, less ice being formed.

Less ice forms in peripheral seas that normally contribute to early extent loss.  Ice doesn't thicken as much in central regions.

QED, the heat isn't melting more ice.  That energy budget annually is actually pretty much fixed by insolation.  It's gone up slightly, but that has more to do with increases in heat imported via currents, which doesn't vary as dramatically over the year as does insolation and weather.  However, you can see looking at Jim Pettit's excellent graph that average annual ice loss has only increased by about 15% or so, and any given year can vary as much as 10-15% above or below that average.

The annual maximum is where the story really rests - that's decreased by around 40%...

http://iwantsomeproof.com/extimg/siv_annual_max_loss_and_ice_remaining.png

So in that context, even with our recent very warm winters, what's happening this melt season with an apparently "anemic" melt is entirely within the kind of deviation range I'd expect.

38
Arctic sea ice / Re: Arctic Ocean Changes
« on: July 17, 2018, 10:20:35 PM »
so maybe it will be like the day after tomorrow  :P ::)

There is so much we don't know yet about how climate/nature works :(

We know enough that we can say the "day after tomorrow" scenario is pure nonsense.

We can be fairly certain of reaching an Equable climate based on what we've seen in the fossil record from the Pliocene.  400-410PPM CO2 produced summer SST's which probably ran near 15C at the pole.  We can still expect that, even with changes in ocean circulation caused by continental drift.

The change from multi-cell to single cell atmospheric circulation will totally change the northern hemisphere.  Whether the same thing will happen in the south is not yet certain.  We also know the transition will be unstable, and will provide us with far more extremes (cold and hot) as we're starting to see now.  Eventually at least in the NH, we will see an end to sea ice outside of continental margins in winter (cold continent/warm ocean) with attendant weather.  Hopefully we can forestall that to save the GIS, but that may be a long shot.  If not, hopefully we can slow the melt so it isn't too disruptive to life. 

But make no mistake, unless we can pull CO2 out of the atmosphere, we will have a year-round blue water arctic within 2 centuries.

39
Arctic sea ice / Re: The 2018 melting season
« on: July 08, 2018, 07:44:07 PM »
4 day GIF of the western Kara illustrative of a phenomena I mused over on the area and extent thread - large stretches of ice disintegrating into smaller and smaller floes which continue to occupy approximately the same extent.
(click to animate)

40
Arctic sea ice / Re: The 2018 melting season
« on: July 01, 2018, 09:20:54 PM »
<snip>
For now it looks as though there won't be as much melting momentum as there was in 2007, 2010 and 2012, which would mean it will take more weather for 2018 to end near record low levels. But the information we have, isn't perfect, and so I'd like to hold out. I hope to look more intently at May and June this week and thoroughly compare to previous years.

While looking at the weather forecast, of course.

This morning's ECMWF forecast has the cyclone at 975 hPa now, starting the day after tomorrow, which then de-intensifies and slowly moves towards the Beaufort, all the while surrounded by high pressure. If the high pressure above the Kara Sea comes about, it's a new region that receives a solar blast.
It was suggested elsewhere that the coming cyclone(s) would pull cold air into the Beaufort. ECMWF really doesn't show that until WAY ahead - like +240 hours. 

Until then, and specifically in the next 96-120 hours, it does show very considerable heat in the region, along with (via Climate Reanalyzer) considerable precipitation in the form of rain.

Prior to that, the pulse of heat and rain will hit the ESS, Chukchi and eastern Laptev very hard indeed.

We may not see a record low this year, but the ice is still taking a serious pounding.

41
Arctic sea ice / Re: The 2018 melting season
« on: June 23, 2018, 08:00:19 PM »
There was some discussion elsewhere about snow cover and albedo and how it was affecting melt.  To redirect that some, this is the Beaufort with very little overcast on the 22nd.

While there is some now cover, it is generally light, and much of the area does have coloration suggesting developing melt ponds.  Snow on land on Banks and adjacent islands has diminished and appears primarily relegated to higher elevations.

That said, extrapolating from what we see on land and relative brightness of the ice, snow cover *is* much higher than any year I looked at in Worldview going back to 2002, with the possible exception of 2009.

The difference is primarily concentrated over the CAA, which would follow from discussions of what effectively is a cold pump over Greenland pulling air around across the CAA and the Northern Beaufort down over the Laurentide region, Baffin bay and Labrador.

The more coastal Beaufort doesn't appear to be significantly snow covered.  All in all what's happening might be the mechanism which creates a "bastion" of ice against the CAA and NW Greenland, through more general sharper declines elsewhere in the arctic.

42
Arctic sea ice / Re: The 2018 melting season
« on: June 19, 2018, 06:47:02 AM »
Friv suggested on another thread that the Beaufort is not as vulnerable as in past years because it appears to  have escaped torching that took place on the Siberian side a few days ago.

I'm not sure I agree.  There are ways in which 2018 is as messed up as 2012.  2013 and 2014 actually appeared to have more melt ponds than either 2012 or 2018.  I don't think we can declare the ice safe from a fairly steep dive, especially with compactness dropping as hard as it has in the last 48 hours.

43
Arctic sea ice / Re: The 2018 melting season
« on: June 18, 2018, 06:50:05 AM »
Years like 2007, 2011,2012, and 2015 all had major dipole anomalies from late June into August.

Except 2011 lost momentum in late July.

2011 was on a torrid pace as well.

So far 2/3rd of the ice pack has seen essentially no surface melt.

The Beaufort has been completely spared.


Right now almost the entire freaking ice pack. Is cloud covered.

Pretty hohum.

Yes and no.

I'm wondering if that cloudiness is a result of all the additional moisture being imported from further south.

Someday, enough of that will start falling as rain, and I don't care what your albedo is, it will be all over except for the shouting.

44
Arctic sea ice / Re: Arctic Image of the Day
« on: June 16, 2018, 08:09:01 PM »
Images of a an unusual perfectly formed small-scale cyclone-like system offshore the Siberian side of Bering sea (just east of Korfa Bay), sent by, and relayed from, a friend who's an avid reader of this forum:



Pareidolia warranted! :-)
*Wow*!  I remember seeing weather formations like that pop up all over the 2013 map, sometimes quite a bit smaller.

45
Arctic sea ice / Re: How soon could we go ice free?
« on: June 16, 2018, 07:31:46 PM »
The most common pattern in general systems dynamics is slow change until an inflection point is reached, followed by a sudden a dramatic change to a new state.  In the mathematics, these sudden changes at inflection points in the potential surface are called catastrophes.  This is where the potential surface no longer supports the current situation and the system has to fall to a new meta-stable state where the potential surface once again supports slow change.

The important thing to note is that we do not have the information required to determine the slope of the potential surface, and therefore cannot have a clue when there will be a catastrophe.
And I think one of those inflection points was 2012. 

Folding in points crandles makes about a system with mostly FYI vs MYI, 2012 and the following years have made exactly that transition.

As a result, a major, MAJOR variable in the dynamic has been taken out of play - something like 95% of the 3+ Meter MYI that used to exist for thousands of years in the Arctic is gone, and it happened in an eyeblink.

The over-all volatility of the system vis-a-vis extent, area and (albeit at a significantly lower level) volume has increased immensely.

With this volatility, statistically it may be we want to look more closely for modal points, rather than median or mean.  I think that will be more reflective of the actual state of the system - as governed by total heat content as affected by seasonal inputs/losses caused by weather and ocean currents.
[edit]
With the loss of MYI, particularly the thicker, 3+M 3+year old ice, the Arctic has lost its "long term memory".  As such the year over year relevance of a previous season's starting and ending states has diminished dramatically.  With out that "information" being carried over, each year is a completely new dice roll, increasingly independent of past ice states.

46
The poll is closed.  People voted relatively high this year, compared to the votes in the June polls of the past 5 years:

I am a lurker the last few months, but one who uses past data to make future predictions I am surprised just how biased the community is. There is so much good science to read about here, but the leaning is strongly alarmist, based on these very clear results. There is a risk that this attitude could also bias the science if not careful.
Considering current weather conditions, ice quality and melt pond fraction in the Arctic, I think most of the predictions are pretty conservative and possibly too high.

I used to use the trend and year over year data to make my estimates.  2013 & 14 smacked me in the face over that. 

More and more I'm trying to get a sense of weather trends and oceanic heat import, as we're seeing on unprecedented levels on both sides of the Arctic.

It all hinges on the weather, and so far, extent numbers notwithstanding, it hasn't been favorable for retention.

47
Arctic sea ice / Re: The 2018 melting season
« on: June 15, 2018, 06:34:04 PM »
Are the anomalies really absurd? Its 6 days to summer solstice and Siberia does get hot in summer. I think its normal to have heat waves and periods of above and well above temperature in parts of Siberia. Western Russia is currently well below average. In a few weeks the pattern can change again.
Not that hot not this consistently.  It's duration more than amplitude people here are concerned over.

48
Arctic sea ice / Re: How soon could we go ice free?
« on: June 14, 2018, 08:02:26 PM »
The real answer is that we don't have a clue.

None of the models has been around long enough to have a valid skill metric assigned to them, and all the models have been way off in one way or another.  The "science" of Arctic Sea Ice is more like Alchemy than Chemistry.  We do not have an equivalent to the periodic table.  Everything that is said is based upon guesses about what is and has been going on.

(This is not to disparage the good work being done.  It is intended to reject the useless expectations people have about that work.)

Wow, I take it you haven't been doing much research on climate change.  You may want to educate yourself by reading the most recent IPCC report.  Here's the link:

http://www.climatechange2013.org/report/

To just toss off decades of science done by hundreds (perhaps thousands) of dedicated, well-educated people smacks of denialism.
No insults please. Dharma Rupa is not a denialist, nor dismissing research.  I think he (And I now) are pointing out that we are attempting to derive system behavior from an *effect* rather than a cause, or at least, an rather incomplete one.

We have very incomplete data. For instance, we have only a vague sense of how total ocean enthalpy is increasing in the Arctic.  We dont know a lot about heat inflow from currents.  Atmospheric chemistry is changing.  Weather itself is a dynamic property that will completely turn our expectations on their heads.

We need much better data about heat, and weather will make a certain prediction impossible even with that.

What we are left with is probabilities and unanswered questions.

49
Arctic sea ice / Re: The 2018 melting season
« on: May 30, 2018, 12:32:00 PM »
I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

It's gone again from today's 00Z forecast. I'm glad I didn't post anything from D7-10 yesterday. Looks completely different now!
Well good. You know part of my plan to save the ice involves making predictions that force the weather to change in order to embarrass me, right?  :P

50
Arctic sea ice / Re: Arctic sea ice minimum early prediction
« on: May 29, 2018, 07:15:12 PM »
And yet, the submitted predictions are heavily skewed towards one end.

In the 1-2 category, I wonder how many voters thought No. 1 (i.e. < 2012) was the probability given that 2012 was 840,000 km2 below the 2nd lowest in the satellite record (2016) ?
The difference between 2nd & 3rd (2007) minima is just 50,000 km2.

Skewed votes in a skewed poll?
... and 4th is only a few thousand more past that.

I was enamoured of statistical analysis at one point until I determined just how useless it is for predicting outcomes in a dynamically changing system.  The clustering of recent minima...all of which since 2007 were  5.1 million KM2 or less... and which follow a distinctly declining trend... underscore this. The differences for many lie within one another's margin of uncertainty.

Previous years totals are about as relevant to one another as year over year stock prices.  I might actually be more skillful with stocks - which is to say not really - evaluating historical data.

Skillful predictive methods and data sources lie elsewhere.

Before someone latches onto this to try and suggest we may recover or this is just natural variability, the trend, which *is* significant is distinctly down, much as total system enthalpy and CO2 levels have increased.

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