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Messages - Niall Dollard

Pages: [1] 2 3
1
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 09, 2020, 05:10:32 AM »
td, bear in mind the process you describe is not unique to this year. This is the mechanism that keeps the North Water Polynya from freezing over. And while the race to guess the Nares breakup is always on early, and no one can know the outcome with certainty, statistics say that a stable southern arch that's been there all winter will strongly resist breakup before June.

From Wikipedia:
Quote
The North Water Polynya (Saqvaaq) is closely connected to Lancaster Sound and Baffin Bay by a powerful system of ocean currents that directly affect the region's climate and biology. In a sense the NOW polynya is a result of the merging of three smaller polynya's Smith Sound, Lady Ann Strait, and Lancaster Sound. The West Greenland Current follows that country's coastline and moves warm and salty Atlantic water north, reaching all the way to the North Water Polynya. An upwelling of warmer water in this polynya helps keep it partially ice-free throughout the year, even when the ocean directly north and south is frozen. Another arm of the West Greenland Current reaches into Lancaster Sound, delivering Atlantic waters into the Arctic Ocean and contributing to that area's rich ecology.

2
Arctic sea ice / Re: The 2020 melting season
« on: April 08, 2020, 11:54:29 PM »
Paul Beckwith is a great wishful thinker, and one of these years he’ll be right, and he’ll be the king of ‘I thusly informed you’ for a while. But I think other people like Neven here have a much much better idea of what is going on in the Arctic.

3
Arctic sea ice / Re: The 2020 melting season
« on: April 04, 2020, 08:03:57 AM »
Indeed. Thanks for that post, N.D.

4
Arctic sea ice / Re: The 2020 melting season
« on: April 04, 2020, 07:46:05 AM »
Around this time of year I usually take a screenshot of the ESRL Ice thickness assessment. Here are the years 2018, 2019 compared with forecast thickness 7th April 2020.
It does n't augur well for the coming summer.
....

Very nice pictures Niall! Confirms what I see on the Bremen maps: unusual weakness from Barents to Kara/Laptev and also on the Alaskan side. It will be very hard to dodge that bullet this year

5
Consequences / Re: COVID-19
« on: April 02, 2020, 01:31:49 AM »
...
I follow the statistics, projections and reports published daily by Swedish health authorities. As of today some new advice and recommendations regarding distancing on public transport and in supermarkets were published. It is now forbidden to visit care homes for the elderly.
...

Swedish bureaucracy at its worst. On Tuesday March 31 they finally decided that our elderly need to be protected. WOW!

For how long did they already know that C19 kills first of all the sick and elderly? First reports about this came in the beginning of February afaik. Statistics and scientifical evidence from Wuhan. More than 6 weeks were lost doing nothing to protect our most vulnerable groups.

Due to their negligence to react and to act in due time on evidence they had, those Swedish politicians and bureaucrats are actively killing our elderly.
Murderers they are.

6
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: March 31, 2020, 09:19:29 PM »
From observation, i've found that ice floes moving south in NS are bound to Ellesmere island. When the current is northwards, the floes are bound to the Greenland side. Can you comment on that?
Excellent observation and the answer goes back to a Norwegian oceanographer Ekman:

In 1905 or so he computed that in the ocean a balance of forces between friction (imposed by the winds) and the Coriolis force results in a flow at the surface (where it moves ice) that is 45 degrees to the right of the wind. As one goes down into the water column, the currents become weaker and change their direction in a clockwise sense. Adding up all these different currents over the top 10-30 meters or so, Ekman (1905) found that the vertically averaged flow is to the right of the wind. In Nares Strait this means that winds from the south move the ice to the east and pile it up off Greenland. The winds (and currents) are mostly from the north in Nares Strait, so this would pile up ice off Ellesmere Island.

All physics is fun and the above argument also explains the fog in San Francisco or, as Mark Twain is said to once said, "The coldest winter I ever spent was a summer in San Francisco." Winds from the South North along the California coastline move surface waters offshore. This surface water is replaced along the coast by much colder waters below the surface. This "upwelling" also is the reason for the great fishing industries that these physics supported - think Cannery Row by Steinbeck.

EDIT: Confused South and North off California, silly me.

7
Arctic sea ice / Re: The 2020 melting season
« on: March 26, 2020, 01:42:48 PM »
I suspect that it is due to heavy cloud cover and/or other atmospheric conditions at this time of year.

Since it's moving around, i agree!

8
Arctic sea ice / Re: The 2020 melting season
« on: March 26, 2020, 12:44:59 PM »
I suspect that it is due to heavy cloud cover and/or other atmospheric conditions at this time of year. There was a similar discussion last year (and some before that)
Here is uni-hamburg mar31 2019 for comparison. It disappeared a few days later.
It is also visible on Aluminium's 2019 link above.

9
Arctic sea ice / Re: The 2020 melting season
« on: March 20, 2020, 12:55:17 PM »
Lets keep to the ice...plenty of threads to talk politics in the subforums.

10
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 02, 2020, 06:50:05 PM »
Meanwhile I see temperatures at Alert have dipped below -40 C. I dont recall that happening last winter.
It is indeed bloody cold up here right now.  Our 24 hour minimum at the lab is currently -44.5, while the latest five minute average is -42.8.  The trend is still downwards, so it's quite possible it will get even colder yet.  This is officially the coldest weather I've ever experienced!  :)

11
Arctic sea ice / Re: The 2019/2020 freezing season
« on: December 29, 2019, 08:56:00 AM »
Edit : And hurrah - I see that has tipped me over the 500 posts and into the Grease Ice !  ;D

Congratulations man! \o/

12
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 12, 2019, 11:12:49 PM »
If we are eyeballing DMIs graph over Arctic temperaturen, we should start to see some decent extent gains soon. As Friv has pointed out earlier in another thread we should be very grateful that the melting in ESS was so resistent. Otherwise, the situation would have been a lot worse.

Without saying that we won't see what you suggest, we should still keep in mind that the regions above 80N are mostly ice covered by now and the reminder of the AO is quite warm still.

I personally expect a general delay of about 2-3 weeks from pre-2010 averages.

EDIT: copied/corrected from the data thread because it belongs here ;)

13
Arctic sea ice / Re: Arctic Image of the Day
« on: September 25, 2019, 10:24:52 PM »
Only 300 pieces but it is free. GL!  :)

https://www.jigsawplanet.com/?rc=play&pid=1269bc2758c7

14
The rest / Re: Good music
« on: September 23, 2019, 06:41:33 PM »
Jean going all out on his Fairlight :) .
I like it. I have his "Magnetic Fields" record. Also records of Andreas Vollenweider and Tomita.

15
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 09, 2019, 11:21:43 PM »
      And since I am pontificating on statistics, here are some take away messages from the recent graphical posts by Oren, binntho, Archimid and El Cid (and thanks to all).

RE binntho's Extent and Area straight line trend
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227604.html#msg227604
     While it certainly looks like a significant downward trend, you can't say the slope is different from zero without doing the stats.  It probably is, but your use of the visual assessment method is no more valid than it is for the folks arguing that the process has stalled because it looks that way in the last 10-13 years (again I am shameless, the same applies to me too, my sinful nature was noted in previous post.  We are all fallen creatures.)

RE Oren's CAB volume trend and thickness graph
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227570.html#msg227570
    That's almost the chart I was hoping for, but it would be even better with a straight line regression trendline, tested for difference from zero, and then extended out 20 years to 2040.  FWIW, if you squint and draw a straight line through the CAB volume trend for Day 243, aka end of melt season, the slope of that line will indicate about 4 million km3 decline from 2000 to 2019, i.e. 19 years.  If that trend continues, then take another 4M km3 over next 19 years and it reaches zero in ca. 2038.  That's only a few years later than the Wipneus straight line projection of sea ice volume trend for the entire Arctic.

    The key characteristic about Oren's chart is that it is limited to ice volume in the CAB.  Thus, it presumably removes possible inflation of losses by peripheral seas that are melting out sooner than the CAB.  What started this phase of the discussion was the notion that future loss rate would decline because the CAB would be more resistant to melting.  I think the Oren chart refutes that. 

     I was surprised how strongly negative the CAB end-of-melt-season (i.e. annual minimum, day 243 data) volume is.  The CAB may look like it's been hanging on, but apparently that is the deceptive Extent curve at work.  The CAB has been rotting out from the inside.  As for the future, the presence of ice in the peripheral seas late into the summer might have reduced past losses in CAB.  Their presence has kept Arctic Ocean albedo high and almost certainly reduced pack rotation and transport out through the Farm Strait (and thanks to Tor for insight on importance of  export losses).  With less protection from ice in those peripheral seas as they melt out earlier in the year, the rate of CAB losses could markedly increase in the future. 

   Archimd's graph shows that CAB volume losses appear to already be increasing https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227455.html#msg227455.

     In addition,  the wider amplitude of the fluctuations in El Cid's graph
https://forum.arctic-sea-ice.net/index.php/topic,2348.msg227470.html#msg227470 gives me a bit of the willies because one of the predictors for a nonlinear chaotic system reaching a tipping point is higher variability.  I may be misapplying that concept because max to min amplitude is not the same as variability between years, but I allow myself my own superstitions.

    But 2038 as the projected zero year for CAB sea ice volume is over a century earlier than binntho's trend extension showing Extent not reaching zero until 2187. How can that be?   Extent is not declining as fast as volume because the remaining volume is being contained in thinner and thinner ice, and thus the Extent does not decline as much as it would if thickness remained constant.  But as the thinnest ice contributing to Extent reaches zero thickness, it stops contributing to the Extent number.  In the end, the Extent curve and the Volume curves have to meet because zero volume provides zero ice for Extent.

    Which brings me back to Oren's thickness graph.  Total conjecture, but my guess is that once average thickness gets below 1 meter we will start to see the end-of-melt-season Extent curve start catching up with its parent Volume curve.  Ice melting comments elsewhere on ASIF point to the much lower melt resistance of thin vs thick ice.  Regardless of my conjecture, the Extent curve HAS to catch up to the Volume curve eventually.

    Stay tuned.  I think there are wild times ahead for ASI in the very near future because it is on the edge of the precipice.  It will be entertaining for those of us who like to watch numerical systems evolve.  Too bad it isn't just a horse race or some other innocuous event, but is instead the loss of a crucial component for meteorological and climatic stability on the only planet in the universe known to host self-aware, so-called "intelligent" life (actually any life, but I think we will soon see that microbes are just about as common as water).  As my brother, a conservative who bought into the climate hoax BS for a while, but who is too smart to stay ignorant, said when he came to see the big picture: "This story does not end well".

   

16
Arctic sea ice / Re: The 2019 melting season
« on: September 08, 2019, 07:32:15 AM »
Can this be considered clear proof that low pressure systems puch the ice outwards?
https://go.nasa.gov/2UGRLuU

I doubt if there is any more debate on this Freegrass. When last we mentioned this, it went on too long and Neven snipped it.

I commented on the way wind is pulled towards the centre of low pressures (due to surface friction). But that is only for wind and the coriolis effect is predominant for ice floes/drift. Ice will drift to the right (of the isobar) in the northern hemisphere, outwards from the low centre. I was mixing up ice drift with wind and stand corrected on this.
I didn't want to continue the debate Niall. I agree that the debate is settled now. I just thought this was a beautiful visual on the theory. You'll see it when you zoom in and out a little. It's a perfect storm, visually... ;)

17
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 03, 2019, 09:33:24 PM »
Another look at what I would describe as a new floor which supports a minimum threshold that will prove difficult to breach but looking at ice age instead of volume.

Good discussion.  And nice chart of early March Arctic sea ice portions by age of ice SH.
The chart shows 1st-year ice percentage increased from ca. 38.3% in 1984 to 65.8% in 2018, which summarizes to an average gain of 0.8% per year.  If that rate continued for another 48 years then 1st-year ice would account for nearly 100% of early March Arctic sea ice. 

    My understanding is that in one melt season, about 2 meters of ice thickness is lost.  And that the average thickness of 1st-year ice is also about 2 meters. 

   So... once we get to ca. 100% 1st-year ice at start of the melt season in March, then that ice would be thin enough to all melt out by the end of what is now an average melt season.
 
    Of course, with current and accelerating warming of global average surface temperature, by 2067, i.e. 48 years from now, the typical melt season will be much warmer so the scenario i'm creating here may arrive by 2050.

  There would still be refreezing in winter.  But progressively less on average each year.  So that's another trend to throw into the blender.  With a lower starting volume each year, the year when all, or nearly all, the Arctic sea ice melts out by end of melt season gets even earlier.

   And I end up back with what I consider the simplest and most convincing predictor of when Arctic sea ice annual minimum.  That being the Wipneus graph showing linear trend of annual minimum volume reaching zero around 2030. 
https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/piomas/grf/piomas-trnd7.png?attachauth=ANoY7co-JT1jjQGvpGxNEvrl0OaSjsV--ZIsZkJxM9mAn3liTvPonGye-SIwYIoMrdz3WhCjzTF-7eO1y4xjVMqo4Mqe6Py4I4KqkaHO97Qm_F7_j-0wn7hmI_ipG2OPbsk-eONQXLct1Ze62owhGmvWbQvdKVz21eBmKeJaoqz_EeC_3JYndbm6NHkkBDxQHAohuZUi9NrYqBUZ105uBQF7giHXXIyLZiC9G_kb1PqxmVgYs8y-q-WkPdR-VoZitgO_CypQuuTS&attredirects=0

     So no need for my layers of speculation and assumptions, just look at the numbers as graphed by Wipneus!  Also interesting to note that 2019 September minimum volume is going to land just about exactly on the linear trend in the Wipneus graph. 

18
Arctic sea ice / Re: Arctic Image of the Day
« on: July 12, 2019, 09:51:27 AM »
Nice Helmholtz-like waves at the edge of the remaining ice in the Kara sea today

19
Arctic sea ice / Re: The 2019 melting season
« on: July 11, 2019, 01:48:25 PM »
worldview terra modis overlayed with unihamburg amsr2-uhh at 35% transparency, may1-jul10. amsr2 100% concentration has been set to transparent to allow worldview features to show through. There is some misalignment in floe movement, probably due to images formed at different hours during the day. This method helps to continue to see ice movement 'through the clouds'
Large format to show detail, best viewed full screen. (double click)
Both sets of images have small contrast adjustment.
edit: Much of the 'blueing' is from the amsr2 layer, indicating lower concentration ice, slightly darker due to the contrast adjustment
added amsr2-uhh, jul10 for clarification

20
Arctic sea ice / Re: Arctic Image of the Day
« on: June 14, 2019, 06:17:10 PM »
This is the largest "melt pond" I have ever seen on the internet. This photo was taken on the NW coast of Greenland. Stunning.

https://twitter.com/RasmusTonboe
@SteffenMalskaer got the difficult task of retrieving our oceanographic moorings and weather station on sea ice in North West Greenland this year. Rapid melt and sea ice with low permeability and few cracks leaves the melt water on top.

21
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 10, 2019, 06:29:38 AM »
BOOM!

22
Arctic sea ice / Re: Latest PIOMAS update (June 2019)
« on: June 05, 2019, 04:55:07 PM »
Data for PIOMAS-20C is now available: http://psc.apl.uw.edu/research/projects/piomas-20c/

23
Arctic sea ice / Re: The 2019 melting season
« on: May 29, 2019, 01:55:36 PM »
The Barrow AK temperature mystery comes from the weatherbug website (1st link below) which was mentioned upthread as a "weather" link from the webcam page (2nd link below).

https://www.weatherbug.com/weather-forecast/now/barrow-ak-99791
https://seaice.alaska.edu/gi/observatories/barrow_webcam/

The mystery arises when the weatherbug page is reset from Fahrenheit to Celsius (button on the top tool bar). Odd things happen unless the page is refreshed.

24
Greenland and Arctic Circle / Re: The 'Very Big Chunk' poll
« on: May 12, 2019, 12:14:50 AM »
Latest Sentinel image. I have never seen the Lincoln look like this:
AH, how long have you been looking? (Longer than 3 years?)
Maybe I'm jaded, but I presume I've seen the Lincoln Sea 'totally' chopped up like this.  Maybe only much later in the melting season (as someone suggested), which would be bad enough (for the health of an icy Arctic) then.

AH and Tor,

This year is quite unusual and far ahead of others. In 20 years of watching the ice conditions, this is both horrible and not unexpected. I have been watching the ice closely ever since the Terra and Aqua satellites first came on line, and sporadically before that with the earlier imagery. In those first years of this new age, your had to go to the NASA website for Terra and Aqua and wander through the individual photo images in various sizes and resolutions and bands. It is so much easier now to just look at the mosaic on EOSDIS, pick your layers, run little moves, scan around, rotate and ...

I remember so clearly watching in horror when the multiyear ice failed north of Ellesmere for the first time in recorded history and drained an ephemeral lake that contained a unique ecosystem that was estimated to be over 3,000 years old.

Now it is routine to see the ice break up in the Lincoln sea, though nothing like what we are seeing this year.

More startling is the extreme shattering of the formerly multiyear ice to the west of the Lincoln sea along the north coast of Ellesmere. The long wide rip in the ice all the way to the other end of the northwest passage has happened before (in recent years). But I do not recall the ice ever shattering along the arctic side of that open lede like it is this year.

It has been happening since before 2000, and was especially severe in 2004, 2005, and 2008, then in the past few years. Still, the breakup this year is unprecedented, just as the breakup of the Lincoln Sea is.

There is simply no integrity at all left to what used to be land fast multiyear ice. The only exceptions might be in some of the channels between the islands that make up Ellesmere.

New this year is the connection between the shattered ice moving north of Greenland and exiting into the Atlantic with the shattered ice in the Lincoln Sea exiting to the south.

I would not be surprised at all this year or in the next few to see a complete breakup of the former multi-year ice all the way from the Atlantic to the Beaufort Sea and a hundred miles off shore of Ellesmere, with shattered ice being chewed up and spit out into the Atlantic, out through the Lincoln Sea and into the Beaufort simultaneously. We already see that happening in segments. And the Lincoln Sea breakup is now fully connect to the breakup north of Greenland. The rip along Ellesmere has nearly completed the free flowing connection of shattered ice moving to the Beaufort.

It used to be that the currents in the Lincoln Sea oscillated strongly across the "ice bridge" between flowing into and out of the arctic through the Lincoln Sea. Now it seems to be almost uniformly out of the Lincoln Sea to the south, with the ice being thin enough to be shattered on contact with the basalt.

As the old ice is rapidly lost, the average thickness of the ice is falling quickly, and the end of the ice rapidly approaches.

Sam

25
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 27, 2019, 07:10:52 AM »
Fatal crash in Nares Strait. Police looking for witnesses.

26
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 26, 2019, 11:52:16 PM »
Welcome to the Arctic Sea Ice Forum, Kevin

We love to have your pictures - as you say it gives a different perspective.

The Nares Strait has been flowing steadily this year. There is a huge difference when the arch does not form in the strait.

Do you mind if I ask you what is the building over to the left of the picture ?
Thanks Niall!

That building is known around these parts as the old transmitter building.  Once upon a time it held an assortment of HF transmitters that CFS Alert used to communicate with the south, but since the advent of the microwave repeater system and satellite link, it's been emptied out and turned into unheated storage for our miscellaneous pieces of junk: mostly equipment cases and construction materials.

27
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 24, 2019, 05:47:15 PM »
A new toy!  GIFMaker.org
I stitched three DMI Sentinel images together (not perfectly, alas) for each of 2 dates, added dates (text) and 3 pairs of dots (on identifiable floes) all using Snagit (which is on my computer), then downloaded the two resultant images into GIFMaker (slowed it down to 1.1 sec), cropped the GIF size, used "Level 1 Optimization" and reduced to 75 colors (cutting file size almost in half).
A click will make it move (in a new window)!

Kane and Hall Basin floes are moving much faster than those in the Lincoln Sea (as 'always') (57, 43 and 7 km/'day', respectively).  (For scale, Petermann Fjord is 15 km wide.)

28
Arctic sea ice / Ice edge at minimum poll
« on: April 08, 2019, 11:08:18 PM »
There may be a gloomy melting season ahead. Here is a lighthearted competition to take our minds off the seriousness of it all.
Two brave posters have already made predictions for the shape of the ice edge at minimum in september. The winner of this poll has the dubious honour of becoming option1 in the july poll. Hopefully you will be able to change your vote. If not, I'll wait till the 20th when entries close and ask neven to fix it.

Three simple steps to submit an entry:
download the top map named option1
add your own prediction using a new colour.
attach your prediction to a post on this thread giving the colour a name.
New entries will then be added to the options

In the event that there are 2 very similar entries the earliest will be added to the options.
Maximum number of dimensions = 24. That's probably about 11 entries.
Closing date for entries is 20th april, voting closes on 30th.

Hat tip to Niall and bbr for the idea

29
Consequences / Re: Weird Weather and anecdotal stories about climate change
« on: February 08, 2019, 04:21:55 AM »
Regarding the issues around meteorological stations moving, I worked on a climate adaptation plan for our community a few years back. Part of our work involved climate projections. We wanted to start with base lines. This proved really problematic because the station moved multiple times, and is now 14km from the original location, in a narrow valley perpendicular to the original wide open location. The new location is prone to summer frosts, colder cold snaps, much lower winds and more precipitation. So we were really handicapped. The meteorological records did not line up with records else where- ya know, the ones that show a warming in the early 20th century, cooling until the 60's and warming since then. The best record we found, which turned out to be a perfect match for global trends, was the dates of the ice break up on the river, which has been recorded annually in exactly the same way since the 1890s because locals bet on the exact time of breakup.

30
Arctic sea ice / Re: The 2018/2019 freezing season
« on: February 03, 2019, 02:21:59 PM »
More data, SAT for January. Second lowest Arctic-wide for the last 15 years, all sectors down compared to last three years:


31
so "the man is back" since a few days only and i was really wondering how long it takes until bickering based on ego-driven posts will start.

for those who are not aware, we're talking remotely and/or directly about re-glacification, new cold phase in the current ice-age and cooling through perforation of the greenland ice-shield.

so after the freezing threads and the snow cover threads this time the focus has been laid on weird weather thread.

thing is that latest once is quoting some of the nonsense and/or whining one can see it, no matter all the efforts to avoid it.

yeah, deniars are now those who don't believe in the above mentioned but think that the globe is still warming.

no matter what weather makes and how local temps peak on each end of the scale, once average temps will be >5C above pre-industrial, even the coldest spots in winter will see higher average temps measured over 12 months or several years. period IMO

all the rest is just noise and babble to no avail or benefit other for some to stick out by making extreme statements.

32
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 16, 2018, 11:57:59 PM »
thank you.  and to Niall also. 

33
Arctic sea ice / Re: Winter Temperatures in the Arctic
« on: December 16, 2018, 08:23:29 AM »
I do not know how the red line is derived - I've heard it said that the temperatures are more concentrated towards the actual pole itself (rather than calculated as an average of points within the 80N circle). It would be useful to know exactly how it is done.

From a link on the DMI website:
Quote
Since the data are gridded, it is
straight forward to deduce the average temperature North of 80 degree North.
However, since the model is gridded in a regular 0.5 degree grid, the mean
temperature values are strongly biased towards the temperature in the most
northern part of the Arctic! Therefore, do NOT use this measure as an actual
physical mean temperature of the arctic. The 'plus 80 North mean temperature'
graphs can be used for comparing one year to an other.
It's not weighted by area but by degree, hence the circle 89-90 has the same weight as the much larger circle 80-81.

34
Arctic sea ice / Re: Latest PIOMAS update (December)
« on: December 04, 2018, 08:24:05 AM »
PIOMAS data has been updated, both the "official" volume data and graphs as the gridded thickness data.

Volume on 30th November was 11.453 [1000 km3], which is the sixth lowest value for that day.

As I am still downloading the gridded data, we start with the volume and volume-anomaly graphs.

35
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 25, 2018, 03:52:21 PM »
A comparison of Chukchi ice extent from 2015-2018, nov1-24 using amsr2-uhh.
The main ice edge for each year from 2015-2017 has been extracted using edge detect in imagej, then splitting the colour channels to remove some of the concentration data, so it should be seen only as a rough comparison.

36
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 08, 2018, 10:18:48 AM »
So this is the rolling average past 12 month piomas volume of the CAB (based on Wipneus' file, attached). You can see that we lost cca 5000km3 from 1995 to 2011 (annual average loss of cca 300+ km3, which lineary extrapolated should have pointed to 0km3 remaining by around 2030), but it has been moving sideways in the past 7 years. The central pack is a hard nut to crack. We might see another 10 yrs of sideways movement or we might see a huge decline even the next few years. It is impossible to say. But extrapolation will not help.

I also attach an extrapolation from 2010 to 2018. It was such a nice fit, and still  it was a huge miss! Based on 2010 extrapolations, we should be around 5000 km3 average volume, whereas in realitywe are at 7400

 

37
Arctic sea ice / Re: The 2018/2019 freezing season
« on: September 28, 2018, 08:42:24 PM »
Profuse assumptions are being made. We cannot assume the atmospheric temperature profile under areas of high pressure at 850 MB or 500 MB, will correlate to the surface being as anomalously warm, as it would during northern hemisphere summer.





It is probable, there will be a layer of closer to average temperatures near the surface, than at higher altitudes, due to less solar isolation (less surface heating) and a cooler surface.

I predict northern hemisphere sea ice extent and area will continue to increase, albeit with a slower increase than average. The 850 MB and 500 MB anomalies are not indicative of the actual surface anomaly after northern hemisphere summer.

The decrease in cloud thickness / coverage under high pressure, should also allow for more heat energy to radiate into space. This could also increase the heat anomaly at 850 MB and 500 MB.


38
Arctic sea ice / Re: The 2018 melting season
« on: September 14, 2018, 03:29:46 PM »
Sentinel image today of the remaining bits of ice in the ESS nearest the Russian Coast. The land area to the SE of the image is Ayon, which is at the left entrance to the large Chaunaskaya Bay.

The ice bits are close to 25km or so from the land. Large tracts of the ESS are like this. I wonder would any of this make the NSIDC 15% ice extent threshold ?

No, in the NSIDC concentration map for 13 September that entire area is 0% concentration.  The "ice edge" of 15% concentration is about 250 km further north.

In the image below, white is "ice" (over 15% concentration).  Blue is under 15%, and actually is 0% for most of this area.  The small dark rectangle at bottom is your Sentinel-2 image.


For comparison, here's the map of extent directly from NSIDC, for the same date:


Its been pretty amazing to watch.  All the extent within that rather diaphanous area of ice would be considered "ice covered". 

Actually, none of the extent within that diaphanous area would be considered "ice covered".  In this case, NSIDC is underestimating the ice concentration, not overestimating it.

39
Consequences / Re: Wildfires
« on: August 19, 2018, 08:59:30 PM »
Crazy fire year here (again) in BC. The smoke is insufferable as well. Here's a pic from the bridge across Lake Okanagan, in my neck of the woods. On a normal clear day vs. yesterday. (today looks even worse, from my window)


40
Permafrost / Re: Northern Hemisphere snow cover
« on: July 27, 2018, 03:13:21 AM »
I'm working on a simple (non-gridded) version of my AWP anomaly model for the Northern Hemisphere land cover in order to quantify the effect of the increased snow extent we had the last few springs. There will still be a continental breakdown of Eurasia, North America and Greenland because the Latitude changes differently on each for the same snow extent values.

What's definitely clear is that the most important months are May and June. The autumn does hardly matter because the solar intensity is too low. Overall there is of course a strong warming trend. 2017 causes a drop in the 5 year moving average, and 2018 doesn't make up for it. (until June)

Maybe I finish it sometime in August and will post a better description and analysis on my website.
https://sites.google.com/site/cryospherecomputing/awp

All snow extent data is from Rutgers University:
https://climate.rutgers.edu/snowcover/table_area.php?ui_set=2

Here are some preliminary Graphs for the whole Northern Hemisphere.

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