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Messages - SimonF92

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1
Arctic sea ice / Re: The 2019 melting season
« on: May 07, 2019, 04:15:31 PM »
Thanks for the comments everyone, I took gerontocrats advice and plotted the regression (sept minima not year maxima). FDD as a whole seems to be a pretty poor predictor of the cycle end-point.

This is an imperfect way to plot this, but my university firewall prevents me from accessing ftp files meaning I need to do it all manually. Also the fact these FDD data points are Jan-Jan, but the Sept minimum occurs 3/5ths into the year makes it worse.

I suppose what im trying to show here is that I shouldnt really have taken any inference from the FDD data about what way the ice could go  :)!
Tealight's AWP graphs and maps give the daily and accumulated potential energy over and in the Arctic. Goto https://cryospherecomputing.tk/NRTawp.html

I attach his "High Arctic" graphs that include only the following regions: Kara Sea, Laptev Sea, East Siberian Sea, Chukchi Sea, Beaufort Sea, Canadian Archipelago, Central Arctic
incidentally, the same seas I show as the Central Arctic Seas in the area tables I post in the extent data thread.

I am sure that they give a much better idea of the current and future state of Arctic Sea Ice (as Tealight has proved once already - Champion of Antarctic Sea Ice Predictors ("No time for losers!?)
(https://forum.arctic-sea-ice.net/index.php/topic,1749.msg197999.html#msg197999)
[/quote]

great, many thanks for these resources gerontocrat

2
Arctic sea ice / Re: The 2019 melting season
« on: May 07, 2019, 03:36:01 PM »
Thanks for the comments everyone, I took gerontocrats advice and plotted the regression (sept minima not year maxima). FDD as a whole seems to be a pretty poor predictor of the cycle end-point.

This is an imperfect way to plot this, but my university firewall prevents me from accessing ftp files meaning I need to do it all manually. Also the fact these FDD data points are Jan-Jan, but the Sept minimum occurs 3/5ths into the year makes it worse.

I suppose what im trying to show here is that I shouldnt really have taken any inference from the FDD data about what way the ice could go  :)!

3
Arctic sea ice / Re: The 2019 melting season
« on: May 07, 2019, 01:07:03 PM »
Back on topic;

JAXA extent continues to track with 2016 (a bad year indeed), yet the FDD implies the ice is actually in pretty good shape and is similar to 2013 (one of the best years of the decade)?

4
Arctic sea ice / Re: The 2019 melting season
« on: May 07, 2019, 01:00:41 PM »
3 incorrect predictions and then the user gets a warning label stuck over their username for all to see?

5
Arctic sea ice / Re: The 2019 melting season
« on: April 25, 2019, 05:17:46 PM »
Melt ponds in the north Pole and whole CAB in the early May? The DMI north of 80 temperatures above 0C 6 weeks earlier than usual?

I doubt DMI will go past 0 that soon, there is still a lot of cold kicking around

6
Arctic sea ice / Re: The 2019 melting season
« on: April 18, 2019, 05:20:36 PM »
Everything looking pretty terrible then, should be a good season on here in that case
:)

7
Whats the consensus? Is a high snow mass overlaying sea ice a good or a bad thing?

I know that melt-ponding that in turn was partially responsible for the June cliff of 2012, but then again there's an inference for increased protection from top-melt?

8
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 05, 2019, 12:26:23 PM »
February 25 - March 4.

Sea ice off the coast of Bear island is probably a rare sight these days

9
Arctic sea ice / Re: The 2018/2019 freezing season
« on: February 28, 2019, 03:52:23 PM »
Its colder in Texas than on the North Slope today. In February. This will be preconditioning for melt-vulnerability.

10
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 12, 2019, 12:45:18 AM »
Shame, would have spurred some interesting reading had it happened.

Forgive my naivety.

11
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 11, 2019, 10:26:14 PM »
 ???

Current and potentially sustained anomalously cool ocean surface conditions for the next few days in the Fram and southward.

Could this be a totally unexpected (brief) return of the Odden?

12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 01, 2019, 04:14:34 PM »
Happy (WACCy) New Year....

There's a major SSW- Event underway, gonna split the Polar Vortex into bits.


We could use a bit of WACCy weather in Scotland at the moment. I have never seen such little early-season snow in 10+ years of winter climbing (there is none below 3500ft).

I'm actually hoping the split aims some of the cold air at us, though that's rarely the case.

13
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 24, 2018, 04:37:14 PM »
AMSR2 regional data anomalies for today's date
(2018- 2012->2018 mean)

I couldn't figure out a good way to normalise this to area-of-the-sea-of-interest so there is a bias in the size of the bars to some extent.

14
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 06, 2018, 03:52:38 PM »
Arguing as passionate scientists/researchers/hobbyists is healthy so long as it is respectful.

I for one found this paper informative; I think people are at odds because they are speaking largely in cross-purposes;

One can "split" and the other cannot;

https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-15-00212.1

15
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 03, 2018, 09:30:12 PM »
Western Hudson beginning to freeze south of Arviat. Freeze onset date appears to be on track to be early;

(Their freeze-up threshold is 20% extent)

Andrews, J., Babb, D. and Barber, D.G., 2018. Climate change and sea ice: Shipping in Hudson Bay, Hudson Strait, and Foxe Basin (1980–2016). Elem Sci Anth, 6(1), p.19. DOI: http://doi.org/10.1525/elementa.281

16
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 14, 2018, 11:55:03 AM »
Looks like extent gains are finally beginning to get going in the CAB

Oct 13th - Oct 11th

17
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 09, 2018, 10:18:04 AM »
Is the ice in Fram Strait right now old ice or newly frozen ice?

Looks like export on Worldview with some nilas filling in between the floes at higher latitudes

18
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 07, 2018, 07:14:13 PM »

You are avoiding acknowledging that while extent has been flat in Winter and Spring, SWE has not been flat.  These are two different things.


I'm not sure i'm "avoiding acknowledging" anything. Spring winter snow extent has not been flat, it has actually declined. Winter snow extent has been flat, while autumn extent has increased.

SWE may or may not have increased in winter, it's not an easy metric to establish, but this paper seems to say that it has decreased (or at least not increased).


Though we can both agree high-Arctic SWE positive anomalies, which cause delayed melt-outs, (and have been causing these in the CAA) are going to contribute much more to glaciation than some extra southerly snow in North America.


Well, I'm not sure what I'm supposed to agree on here. Positive SWE anomalies are not contributing to glaciation, as there are is no imminent glaciation. For glaciation to happen, both high SWE and increases in extent in spring and summer are necessary.



It is very important when reading papers not to over-stretch what one takes from them, but its also dangerous to ignore the bigger picture of their discussions. We're all very keen to point out the inferences of albedo on the Arctic Ocean and where it will lead us. So why not discuss this too?

Any change in extent affects albedo - SWE make no difference. And it doesn't seem to me that there has been any increase in snow albedo, since winter extent has been flat, and autumn increase is cancelled out by spring decrease.

All in all, I can't how bbr's hypothesis can supported by recent trends or by the paper you linked to.

Though I don't speak for bbr, and i'm sorry should he take this personally, but I think his statement was somewhat tongue-in-cheek, as opposed to a serious hypothesis.

However, though exaggerated, he does make a valid point. The paper I attached discusses how decreasing ASI cover leads to increased Autumn snowfall. I know you have seen the crazy SWE maps for last year. It started snowing early, and the volume ended up literally off the GCW scale by mid-winter.

Glaciation is driven by a either a combination of lower summer temperatures and increased Autumn/Winter/Spring snowfall versus control, or an overwhelming contribution from one factor. The paper sets out a reasonable argument for the latter of these two mechanisms. Maybe, some areas in the CAA may see positive SMBs as a result of this, in the years and decades to come (Greenland has seen this effect for the last 2 years). I dont think my argument is invalid, or I wouldn't make the point- though you may well prove to be correct.

19
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 07, 2018, 03:03:30 PM »

Year round BOE is a fallacy. the impact of summer BOE + extant ice sheet over Greenland = we snowball back to glaciation well before we approach BOE all year.
...

I doubt that dramatic statement.
Can you give a reference to some scientific research on this?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306672/

That paper describes the potential positive feedback of a warming Arctic Ocean on "colder" landmasses and by inference increased glaciation.

The above mentioned paper is not really saying anything that others haven't pointed out already: Decrease in Arctic Sea Ice is, at least partially, responsible for increase in snowfall during autumn in the Northern Hemisphere.

But there is a big difference between increased autumn snowfall and "snowballing back to glaciation" - and the above mentioned paper makes no such claims.

Autumn snow has been increasing these last several decades, winter snow cover is more or less flat, spring snow cover has been decreasing - all as expected in a warming world with more moisture.

You are avoiding acknowledging that while extent has been flat in Winter and Spring, SWE has not been flat.  These are two different things.

Though we can both agree high-Arctic SWE positive anomalies, which cause delayed melt-outs, (and have been causing these in the CAA) are going to contribute much more to glaciation than some extra southerly snow in North America.

It is very important when reading papers not to over-stretch what one takes from them, but its also dangerous to ignore the bigger picture of their discussions. We're all very keen to point out the inferences of albedo on the Arctic Ocean and where it will lead us. So why not discuss this too?

20
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 07, 2018, 02:16:49 PM »

Year round BOE is a fallacy. the impact of summer BOE + extant ice sheet over Greenland = we snowball back to glaciation well before we approach BOE all year.
...

I doubt that dramatic statement.
Can you give a reference to some scientific research on this?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306672/

That paper describes the potential positive feedback of a warming Arctic Ocean on "colder" landmasses and by inference increased glaciation.

21
Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 04, 2018, 07:13:21 PM »
I think this graph shows best when we can expect BOE


One generally wouldn't fit a linear regression to a complex system (nor expect it to be the best fit)

22
Arctic sea ice / Re: The 2018 melting season
« on: August 08, 2018, 11:19:27 AM »
While the ESS is under attack, there is a persistent spinal structure in the center that seems to withstand thawing or dispersion for quite a couple of days now.

I thought I recognised that. Same date in 2015, though appearing somewhat more robust 3 years ago.

23
Arctic sea ice / Re: The 2018 melting season
« on: August 07, 2018, 06:08:31 PM »
Interesting kink in the DMI temps recently, probably being facilitated by the high latent heat of peripheral seas.

Wonder how this will affect refreeze, particularly in the ESS.

24
Arctic sea ice / Re: The 2018 melting season
« on: July 20, 2018, 12:27:04 PM »
Isn't the temperature because of the ice? As long as there is ice, it's hard for the temperature to get much above the melting point, because all the heat is going into the ice. And in the summer the temperature is always around/ slightly above melting point, so it can't get a lot warmer yet.

Or is that too easy?

Yes that's correct, the ice acts as a thermal buffer. We will only see temperatures significantly greater than the stable summer mean (+40 years recording [DMI]) further north than the 80th parallel when there is no longer ice left to melt out.

25
Arctic background / Re: Arctic Maps
« on: July 01, 2018, 11:07:09 PM »
One of my favourite resources for whole Arctic maps is the ECM, it gives some really nice theoretical maps based on global temperature changes

http://cci-reanalyzer.org/clim/ecm/


26
Arctic sea ice / Re: The 2018 melting season
« on: June 27, 2018, 10:30:39 AM »
June 22-26.

Interesting how well the Beaufort is holding up this year, considering there has been virtually no buffer-ice in the Bering or Chukchi.

As far as I have seen, there haven't been cold anomalies or any other obvious reasons to explain it. Same goes for the Kara.

27
Arctic sea ice / Re: Land snow cover effect on sea ice
« on: April 20, 2018, 02:40:17 PM »
I've noticed that when people post their musings on the "serious" forums, no exciting discussions ensue because other people don't want to clutter the threads with their replies.

The fun thing about these chatter threads, like this one, are that here we can have discussions about what we think - which we can't in the other forums.

Yes I agree, I tend not to post much on the main threads- best to listen to the real published scientists and well read individuals;

To those talking about "doom and gloom", I do think the forum does over emphasises trends seen in the Sept minima, and is somewhat biased in their reporting. Iv been lurking on here since late- 2014 so I have seen a few years come and go.

I was working on some data with my PI, fitting increasing order polynomials to my datasets to see what happened [irrelevant area of science]. To practise I plotted regressions to the Sept-sea ice minimum area from 1979- 2017 (arguably not the best quantitative data set regarding the Arctic, I know).

What I found was that a linear regression over the whole dataset was a poor analysis method. One could argue a "phase change" occurred in 2007.

Plotting the minima from 2007 onward and fitting a linear regression actually gave a positive gradient. Try it yourselves if you don't believe me. That's 25% of the dataset!

By no means am I suggesting conditions are improving, or a recovery is occurring- that would be completely incorrect. I'm just saying there's no impetus currently to even think about going against the status- quo; and this could end up being detrimental to the discussion.

Tldr; off- topic, please delete if appropriate


28
Arctic sea ice / Re: Land snow cover effect on sea ice
« on: April 18, 2018, 01:07:15 PM »
gerontocrat

thanks for the interesting read

bbr2314

I clocked you a long time ago as someone who acts as a voice of reason, when I think most users of this forum over- exaggerate how "bad" the high Arctic is- take the polls for example, the estimates for Sept Minima are consistently biased toward doom and gloom.

I like reading your posts and generally lean toward agreeing with you.

But I really think that SWE in North East USA and South East Canada is completely irrelevant. Most of that snow will be gone in a few weeks, drained into the Hudson Basin and out towards Newfoundland

29
Arctic sea ice / Re: Land snow cover effect on sea ice
« on: April 15, 2018, 03:03:17 PM »
This paper suggests a "protective" effect of increased Arctic river outflow on Arctic sea ice, through reducing inflow of warmer ocean currents into the CAB. If we extrapolate that increased snow volume will lead to increased meltwater flow, high spring snow volume could be beneficial to sea ice.

"Overall there is a small decrease in the total exchange between the Arctic Ocean and the surrounding seas with increased runoff, contrary to expectations from estuarine circulation theory."

They do acknowledge significant limitations in their multivariate model however, which I always like to see.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC011156

30
Arctic sea ice / Re: Operation IceBridge - Arctic Spring 2018
« on: April 11, 2018, 03:11:05 PM »
Having had a good look at NASAs amazing images, on the micro-scale (now i appreciate these images may be hand picked), does the sea ice north of Greenland seem to be in bad shape?

At least until a few years ago I thought fast ice extended several tens of kilometers off the coast of northern Greenland in the winter and early spring? Especially in April.

Here it looks like dispersed floes, vulnerable to waves.

Am I being naive?

31
Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 27, 2018, 11:11:11 AM »
A guy I work with put me onto a new resource.

It's definitely less esoteric/ scientific than most of the resources shared on here. But it does give some nice real time* data on predominant weather patterns in the high arctic (and world)- as well as some other tidbits.

Plus the GUI is really well designed :).

Hope this is an appropriate place to share, please let me know if not.

https://www.windy.com/?74.776,-36.563,3

32
Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 21, 2018, 10:50:31 AM »


Though if it stays somewhat open on the Arctic/Beaufort side of the straight... then I'm way more worried. I feel like that would require this insane weather (I mean, 0C+ temps! In February!) to continue for more than a month, constant split PV and all that.

Doesn't it have to get down to -11C for new ice to form ? And at higher temps there can't be much thickening. Lower temperatures than this are likely to return, but for how long? Will there be more bouts of high winds to wreck the thin ice with wave action? I think the Bering has seen its extent max for the season and it would surprise to see open water remain until the melt begins in the southern Chukchi -

It looks a dire situation to my eyes anyway. Extent and area are record low despite lots of ice in irrelevant regions in Baffin Bay and the Sea of Okhotsk etc, and the oceans both forbodingly warm, And still another 5 days of insane warmth and wind

One could argue that the Bering Sea is somewhat peripheral/ irrelevant also, and furthermore, the recent storms there could well have compressed the ice into the Chukchi- where it is certainly relevant for it to exist in order to prevent early high-arctic melt. That being said, Bering is toast.

The ice is in bad shape for winter, but I don't think it looks like were setting up for a particularly bad early-summer melt event. Especially when you look at the NH Snow Water Equivalent. Which if my memory serves me correctly, was high last year also, and in turn caused ice to linger on the Siberian coast for a surprisingly long time.

33
Arctic sea ice / Re: The 2017/2018 freezing season
« on: November 30, 2017, 09:47:19 AM »
Hello to all,

I generally like to "lurk" on this forum, there are several experts from whom I have learned a great deal over the last few years.

Firstly to the people who take the time to collate data and figures for the rest of us to learn from, I would like to thank you for your continued efforts in doing so.

I generally visit this forum, DMI temps, cci-reanalyser and NSIDC's website at somepoint most days. Today I noticed that cci-reanalyser has updated their service to provide several new visual data sets on the condition of the arctic (and world). Significant new additions are their Snow Depth figures and 500hPA Geopot. Height.

http://cci-reanalyzer.org/wx/DailySummary/#snowd-mslp

Many thanks again

Simon


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