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Messages - Sailaway

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1
Arctic sea ice / Re: The 2020 melting season
« on: September 08, 2020, 01:51:21 PM »
Ice edge position over the last 14 days

2
The forum / Re: Forum Decorum
« on: August 14, 2020, 12:07:08 PM »
BTW, there have been some obstacles (fuck Brexit), but i'm happy to report that Gero finally got his money this morning. YEY! \o/

3
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 13, 2020, 10:52:36 PM »
Imagej can provide sorted palette capture from the geoTiff example of the new AMSR2 ice concentration file Lars supplied above, using Image -> Color -> Edit LUT.

That palette and its inverse are shown 3x enlarged as gapped and ungapped images. There are 100 colors for the 100 concentration percentages plus 1 for the land mask and 1 for the pole hole lacking satellite data.

The palette is quite pleasant but it's difficult for the eye to distinguish nearby color squares. Perhaps 20 colors would have sufficed in 5% blocks. It would require digging into the raw and processed satellite data to determine whether the instrument really could make such fine distinctions. A ramped palette might also work better.

Here various statistical properties of the data needs to be studied, not only the global palette use histogram (see uniq's data above) but also local variation (do the values vary wildly from the local mean in a 5x5 pixel block or tend to be related?).

That is easy to test in gimp via eyedropper radius settings. Most likely the local variance is minimal in the central CAB but varies a lot towards the edges or over isolated floes so an overlay map of the distribution is needed.

A palette is normally embedded into the image, over land or unused open water, often here probably best as a 10x100 rectangle. Once embedded, shift-clicking on a range allows a palette color or whole range to have its color changed throughout the data.

The gif below lumps rows of the palette into different colors. It shows that much of the palette is hardly used except in the actively melting periphery. Cloud minimization will be very important here to develop accurate images.

Rescaling to a smaller size is very problematic because it cannot be done without dithering of colors. The palette as it comes from ImageJ consists of 10x10 pixel squares so could be halved using 'none' as the interpolation method. However the data layer would dither unless forced to stay within its indexed color palette.

4
Arctic sea ice / Re: The 2020 melting season
« on: August 10, 2020, 11:55:54 PM »
Version 2. Getting there...

5
The forum / Re: Forum Decorum
« on: July 30, 2020, 02:14:05 PM »
I think I found a good rhythm now with the forecasts, no? Temp in the morning, wind and something extra at noon, and in the evening another one. Is everyone ok with this? I'll try to keep it up if you like me to.

6
Arctic sea ice / Re: The 2020 melting season
« on: July 17, 2020, 04:07:34 AM »
It can not be argued that we have (not) seen some extreme surface melting over the last few days.

I added the word "not" that I think you meant to put in there.

I don't think it's very scientific to try and draw boundaries around what can and can not be argued. Clearly there is visible and undeniable evidence supporting the massive extent declines being reported by JAXA. The 2D shrinkage is undeniable.

But there is room for reasonable people to question how much of that shrinkage is due to melting and how much is due to relocation.

There is a lot of evidence which will be forthcoming in the next two months which will shed more light on what has transpired during the GAAC. There isn't any reason to label less common perspectives such as those implied by Nico Sun (and his depiction of a negative current melting energy anomaly) as being invalid at this moment. The likelihood of proof is just around the corner.

I certainly think its fair to criticize and dissect the logic of unpopular arguments, but we should not make declarations that characterize arguments which have yet to be made before the proof. At this point, I don't see proof which enables us to reasonably quantify how much of the extent reduction is due to ice relocation.

Phoenix, please do not engage with me anymore.

Don’t tell me what I meant to say!

The mods let you stay and I won’t question their judgement. But don’t engage with me.  I feel like Shared Humanity right now and maybe I will just delete my account because these forums are too frustrating to participate in anymore.

<Softened the tone. And Please don't leave. O>

7
The forum / Re: Forum Decorum
« on: July 08, 2020, 05:06:58 PM »
Phoenix has been put under moderation, with thanks to Neven. All should expect noise and disruption to subside, and can return to visiting rhe main thread.
Apologies to all who have had to suffer due to my delay in taking care of the matter.

8
Arctic sea ice / Re: The 2020 melting season
« on: June 25, 2020, 08:30:13 AM »
Aluminium, that's an interesting image.
Not only 13.3°C but also a wind speed of 87 Km/h (54 mph, 24 m/s, 9 Bft) over the arctic sea ice.

That's way over the ice at 850 hpa altitude. Down at the surface level sat at that time the temp is 1C.

Really! How totally inane.

At the exact point in Aluminiums graph, at surface on exact same time, the temperature is forecast at 2.8 degrees C. At the same time, temperatures at surface over the ice ranges from 0.2C to 2.9C.

9
Arctic sea ice / Re: The 2020 melting season
« on: April 28, 2020, 02:45:15 AM »
According to Nico Sun's area calculations, we are back in spot #1 today.
And I think that's where we'll stay all season...

IMO, this is a low effort, no value added post. Someone should open a prediction thread for the non-science of guessing future weather events.

Only outdone by your response.

10
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: March 11, 2020, 04:35:30 AM »
Thank you for these tables and for your dependable updates Juan.
You are welcome, Oren!  :)
The true is that I really appreciate this Forum and other people posts (like yours...  ;) ). So, I am glad to make a contribution to this Forum.

Thanks, Neven, for your leadership and work on the Blog and the Forum.

_____________________________

Unlucky, today ADS is sending me to Twitter. It seems that there will be not data today. I will wait an hour, to see if the problem is fixed.

https://ads.nipr.ac.jp/vishop/#/extent


11
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 04, 2019, 11:30:56 AM »
I'll have to take over A-Team's position on this venerable board and start posting updates for you all to follow

You'll have to do a lot more than that to "take over A-Team's position on this venerable board"!

By way of example please see:

https://forum.arctic-sea-ice.net/index.php/topic,2906.msg231704.html#msg231704

12
Arctic sea ice / Re: The 2019 melting season
« on: September 21, 2019, 02:59:49 PM »
Focusing on the near term local while excluding the impacts of larger causes and the larger causes themselves is a grievous mistake.

No it's not Sam. It's the whole point of this thread.

By all means provide a brief explanation in here whilst linking to other threads on the ASIF, academic papers or other web sites that cover the larger causes. If a suitable ASIF thread doesn't already exist feel free to start one.

As has already been pointed out to you, any "larger" points made in here will swiftly become lost below the noise threshold in the weeks, months and years to come.


I hope sark and sam take your advice. Post real time atmospheric behaviors here that are having an effect on the melt season and create a thread that dives into the subject in a more in depth manner with scientific articles as support. Would be a great addition to the site.


13
Antarctica / Re: What's new in Antarctica ?
« on: July 31, 2019, 07:45:12 PM »
So what is level 2? Data for specific programs or the visual output which can be manipulated like A-Team, Uniquorn and others do to some other satellites output?

It is raw gravity data, in a txt file. See ftp://isdcftp.gfz-potsdam.de/grace-fo/DOCUMENTS/Level-2/GRACE-FO_JPL_L2_Processing_Standards_Document_for_RL06.pdf for a description of the content, https://pdfs.semanticscholar.org/a906/232145ab2a7a48d87461abd48a3170ee0dae.pdf for an introduction to spherical harmonic analysis. You get the coefficients C_ml and S_ml, up to order 180. Putting it into a formula will give you a latitude/longitude map of the gravity field, which then needs to be interpreted.
The data itself can be found here, sorted by time interval: ftp://isdcftp.gfz-potsdam.de/grace-fo/Level-2/JPL/RL06/ I guess the logic behind the file names is YYYY"day of year"-YYYY"day of year"_"some stuff".gz, but I didn't bother to read the manual. It should all be in there.

Ah, by the way: Hello ASIF! This is my first post. I have been reading here for a while. I hope I'm not interrupting, and you find the explanation useful.

-- Daniel

14
Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: July 25, 2019, 08:45:57 AM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 24 July 2019

On this day

Melt High but down a bit. Still predominantly in the West. .

Precipitation minimal, and as a result SMB (Surface Mass Balance) loss substantially above average despite the slightly lower melt.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Some precipitation in the south and on the east coast - partly rain?

Melt / Temperatures. Extreme warmth Monday 29 to Wed 31 July. Will it happen? If it does, melt % will likely be new maxima for the year.

High pressure has been, is, and will be stuck over Greenland until ....?
____________________________________________

15
Arctic sea ice / Re: The 2019 melting season
« on: July 23, 2019, 08:50:01 PM »
Getting an early start on the season this year?  ;)

16
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 09:01:15 AM »
You can lead a horse to water....

If your horse is swimming in a moderate 5' swell with 20 knot winds somewhere north of the Bering Strait it might be in some danger of drowning so you best lead it to shore and away from the ice floes which will continue melting in situ!

17
Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 04:48:41 PM »
Can't you just say humanity? I am offended by women exclusion, they're as bad as men.
No, maybe that should be hupersonity to be nonsexist.
No, wait, huperdaughterity?

Can we stop here?  I know it's "just joking around", but intentionally or not, this interchange is acquiring a tone that is mocking of the efforts of women (and men) to produce a world with more equality.  It also communicates a sense that this is forum where men dominate and women must accept their 'second place'.  We should avoid this.  Can we get back to the science? 

18
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 21, 2019, 05:54:35 PM »
I've tried to keep quiet so as not to contribute to the noise, but please - the off-topic (though intelligent) discussions are cluttering this thread, please move them to the "meaningless season chatter" thread where they belong.
The on-topic discussions and rebuttals of Geron's boilerplate commentary should be held in the melting season thread.
(Neven - please punish me if I'm wrong. Please punish everyone else if I'm right)

19
Arctic sea ice / Re: The 2019 melting season
« on: June 06, 2019, 08:45:02 AM »
Well, Friv is much better at impersonating himself than the wannabes who tried it recently!

20
Arctic sea ice / Re: Do we make too much of 2012 ?
« on: June 05, 2019, 12:14:00 PM »
Do we make too much of Imelda Marcos?

 .. what you do in your own time is up to you ! :)  b.c.

21
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 04, 2019, 04:55:30 AM »
At this date in 2012 there was strong evidence of warmth and early melt ponds but the sea ice extent was close to the average for the previous decade. No one could have foreseen the June cliff and GAC that led to the record minimum in September. It was shocking to witness.

We have no reason to predict a June cliff like 2012, or a GAC this year, but extent loss is way ahead of 2012 at this date. Perils of projections, indeed. We have no good basis at this time for saying that this year is likely headed for second place. No weather model is good enough to predict a GAC or lack of one in August of 2019.

If we look at Nico Sun's albedo warming potential this year is way ahead of 2012 for this date. What happened in mid June through August 2012 was completely unprecedented and we cannot anticipate its recurrence. However, this year could see a record minimum if the present sea ice transport and high pressure patterns persist.

I completely agree with your post FOW.

That said, according to Neven's ruling yesterday, we are not supposed to disagree with Gerontocrat's predictions in this thread.

The correct procedure according to Neven's is to copy and paste Gero's comment into another relevant thread (in this case probably the melting season thread) and respond to him there.

Can you please stop with the snarky comments and move on from it?

22
Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: June 02, 2019, 02:18:27 AM »
Thanks Tealight! Great stuff and very much appreciated!  :)

23
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: May 28, 2019, 06:08:15 AM »
JCG, your updates make my updates easier! Please do not change!

24
Arctic sea ice / Re: The 2019 melting season
« on: May 26, 2019, 10:41:38 AM »
Removed a couple of comments. If it's difficult to quit, I can help with that. Next step is moderation/ban.

Wouldn't want free thought or anything.

<Alrighty then, you're on moderation. This has nothing to do with free thought, but rather with the most interesting thread on this forum getting derailed; N.>

25
Arctic sea ice / Re: The 2019 melting season
« on: May 26, 2019, 02:59:00 AM »
You care more about looking smart than educating people.

You indicated you were an engineer, I gave you a short response that I figured was geared toward an engineer. I will try to provide a better Simple English answer in the future to spare you from throwing a tempter tantrum.

26
Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: May 25, 2019, 12:17:25 PM »
Just for clarification are we talking about Metric or Imperial Smidgeon

Thanks
There are 2,204.62 pounds in a Metric ton.
There are 2,240 pounds in an Imperial tonne.
There are 2,000 pounds in a US ton (lightweights!).

So difference not relevant when considering smidgeons, as in the US of A there are no smidgeons, only smidgens.. The 24th May SMB loss was just over 1 thousand million  (1,000,000,000 ) tonnes of smidgeons (1 GT or 1 KM3 of water).
______________________________________________

ps: The dictionary used by the ASIF is American - huh.

27
Arctic sea ice / Re: The 2019 melting season
« on: May 25, 2019, 10:38:14 AM »
Ok, so as Frivolousz21 is not around, I have to replace him:

I'll give you a 5/10 for the effort, but friv cannot be replaced so easily.  ;D

edit: I've just seen the ECMWF forecast and it looks pretty terrible indeed. Anything above 1030 hPa around this time of year, is a disaster for the ice. I'll post the latest forecast this evening.

28
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: May 17, 2019, 11:45:55 AM »

It would be interest to get some kind of sense of how people rank the various variables.

As a newbie, I would guess water temperature is at least up there with atmospheric temperature . Sunlight has been pointed out. The spin which brings ice to Fram seems important. Nares being open with a steady throughput. Wind. The thickness of the ice. The level of surface fracturing.

Thanks for your patience. I'm just trying to get oriented. Asking questions helps.
For discussions on the various parameters that influence sea ice area and extent the 2019 melting season thread (and other threads such as salinity) is where you need to go. There you will find the posts on the weather, the climate, the sea temperatures, the ocean currents etc etc etc. There you will also find the more you know the less you know.

This thread is mostly just about the data itself. I only make a comment on my posts in this thread about where the very short-term direction of travel may be.

Most of us also use the "Stupid Questions" thread from time to time. You will get good answers and links to places within this forum and elsewhere.  It is a big and wide-ranging forum. Good hunting.

29
Antarctica / Re: What's new in Antarctica ?
« on: April 23, 2019, 01:49:47 AM »
The Antarctic Bedrock data was over 10 times harder to align than Greenland. There are hardly any landmarks, just plain white and with fast ice or ice shelfs you don't even know where the land begins. I had to use huge area images to align islands and then cut it down to individual glaciers. The bedrock resolution is just 1km/px as opposed to 0.15km/px for Greenland data.

https://cryospherecomputing.tk/Bedrock-Antarctica

30
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 06, 2019, 09:45:58 PM »
I didn't vote either for lack of a hypothesis of what would happen.



I like to say buying a lottery ticket does not significantly increase your chances of winning the lottery.

31
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 08, 2019, 05:50:27 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.
 
February 7th, 2019:
     13,519,007 km2, an increase of only 5,771 km2.
     2019 is 3rd lowest on record.

Thanks, Juan! Really appreciated. Here every night for Geronto's and your updates.

32
Arctic sea ice / Re: Latest PIOMAS update (January)
« on: February 06, 2019, 08:03:27 PM »
Wow.
'Sic transit gloria mundi' - in one 2-minute video.
A truly stunning story. Many thanks Wipneus.
I intend to use this for educational purposes. How would you like to be credited, please?

33
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 16, 2018, 12:56:06 AM »
The time has come  :)

After a few hours of coding and 1.5h of calculation the AWP and AWP_anomaly data for the Northern Hemisphere is ready to be explored. For eastern Canada, the most discussed Region here I already made two charts of the mean anomaly for April and May.

We have:
21 years * 365 days * 24 Regions * 2 variables = 367,920 values

That will take some time to get through and find all interesting parts. I hope some forum members can explore it too. The data is available as usual on Google Drive and now also on Github.

Google Drive:
https://drive.google.com/drive/u/1/folders/1MiBVuMjoG-TRBsJhwPiChJYF5lKlaaxC
Github:
https://github.com/NicoSun/CryosphereComputing/tree/master/ScienceData/Northern_Hemisphere_AWP

34
Permafrost / Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« on: December 14, 2018, 04:25:24 PM »
In the regional breakdown it's impossible to create exact regions for each individuals preferences. So I chose my regions by considering geographic regions and international borders. (apart from mid latitude Asia, no one there is interested in it anyway)
The regional breakdown is beyond perfect. Thanks.

35
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 30, 2018, 12:17:50 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. after all there will always be winter and even regions with 20C summer water temps and up to 35C air temps are frozen nowadays during winter and that even more south where is no zero sun in winter.

while opinions remain free, my opinion is that headline like buzzwords are not target leading, we should keep it realistic.

36
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: June 08, 2018, 05:53:58 PM »
JAXA Extent 10,482,795 km2(June 7, 2018)

GFS (from cci-reanalyzer) still shows large areas of the Arctic having had, getting, and will continue to get a dose of real warmth. I am increasingly surprised that the effect on extent data is still not obvious yet. Perhaps the effect on the seas in the CAB is more a case of thinning, fracturing and opening of leads rather than larger areas of open water.



83 cm of rain at 1C to will melt 1 cm of ice, and the melting ice buffers the temperature of the water, and, that water at 0C, is fresh and floats. The latent heat of fusion of water soaks up an enormous amount of energy. The ice in the middle of the pack will thin and warm, but not lose extent. this is what Neven calls "Pre-conditioning" it accelerates the July and August extent losses.

Sea ice melts from the edges of the pack. The water at the edges of the pack is dark and heats up quickly, throughout the photic zone, and across a wide area. It is mixed with the ice at the edge of the pack, by wind or wave action, and by some night/day convection as the surface cools and sinks at night. I imagine the best conditions for ice to melt are sunny days with the ice being blown towards open water. I think understanding the mechanism of melt, that heat energy over a wide are of ocean is transferred to the point of melting is critical to understanding the rate of extent loss.

On the Atlantic side, I think A team has made a very good case that the boundary of the sea ice is determined by the bathymetry. The position is relatively stable. The relatively thick cold ice meets the warm dense Atlantic waters, There is enough warm water to melt the ice, and the melting ice cools the water, causing it to sink, a mechanism that tracks the shelf edge. Only when there isn't enough ice to cool the incoming waters will this boundary progress further into the Basin.



37
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

38
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: May 12, 2018, 08:39:05 PM »
Neven - I have a small request. This thread is the first one I go to when on the forum. It would be nice if it could be bolded, like the late IJIS thread used to be.

Done!

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