Please support this Forum and Neven's Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - subgeometer

Pages: [1] 2
1
Arctic sea ice / Re: The 2017 melting season
« on: July 26, 2017, 09:49:04 AM »
Things have been kind of quite lately in the Arctic. Really not that bad of a year. Not much momentum, the melt season seeming to just fizzle out. Or is it just being a little sneakier this year.
21st-25th CLICK IMAGE


GFS predicts a dipole setting up in a day or so with highs returning to the Beaufort, and the PAC drawing in some deeper fast moving lows from about 100hrs. As Pavel noted the weather has been driving the periphery outward toward Russia etc, whereas I can't help think that compaction and consolidation would be better for ice preservation despite the big extent drops that would imply. And there is that monster cyclone developing east of Japan.

2
Arctic sea ice / Re: The 2017 melting season
« on: July 22, 2017, 12:35:16 AM »
NSIDC SIE  x 106 km2

2017,    07,  17,      7.765
2017,    07,  18,      7.640       Down 125k
2017,    07,  19,      7.518       Down 122k
2017,    07,  20,      7.395       Down 123k

 Some have commented that cooler air is on the way for many parts of the Arctic. Still, most surface air will remain above freezing, even if slightly, and insolation will continue either way.
Looks like a little wave activity starting to kick up here and there today and over the next few days. This may redistribute enough warm water to escalate the attack on the sea ice.

The coldest temps are on the Siberian/Pacific side where the ice is thin and SSTs will melt much or all of it out, whereas warm winds are blowing north of Greenland and Ellesmere Island most of the week according to ECMWF/Windy, as well as along the Atlantic fringe. For ice retention it would be better if the core of the cold were between the Pole and Greenland/CAA.

The NH tropical cyclone season is cranking up, so we'll likely soon see one tracking into the Polar region with attendant warmth and moisture.

[edit} And waves... The low tracking from the ESS through the Beaufort will generate large waves right at the ice edge, up to about 4m by the colour of the visual, unfortunately the conditions at location feature doesn't seem to work in the Windy TV 3D view

3
Arctic sea ice / Re: The 2017 melting season
« on: July 20, 2017, 11:04:24 AM »
@subgeometer

It looks like that is going to continue around the Svalbard area for several days, with some ups and downs in wave heights, of course. This should move some of the warm water around, and there is plenty in the area.

Thanks TT

It would also be interesting to see a few profile from the huge swathe of open water  around the coast from Canada to the Laptev.

The waves at Svalbard are being driven by persistent warm southerlies. This low could have a bad effect on the now peripheral Atlantic fringe, while the cold is blown to already melted areas on the Pacific side.


4
Arctic sea ice / Re: The 2017 melting season
« on: July 20, 2017, 06:07:40 AM »
Windy TV predict persistent waves around 2m north of Svalbard this week while warm air is drawn over the Atlantic sector. Also plenty of waves on the Pacific front at various times

I'm not sure how this is determined but it's scary how far into the pack the model sees waves propagating

5
Arctic sea ice / Re: The 2017 melting season
« on: July 17, 2017, 05:10:42 PM »
On the Atlantic side Winds have turned around to come from the south for the next few days, with a big influx of warm air and moisture, And the ice looks bad .

Here is a region from 85-87.6N north of FJL over the past 2 days as well as 850hPa from WindyTV temps showing twin assaults from Pacific and Atlantic. Windy TV has a 3D globe projection! That makes it much more useful,

6
Arctic sea ice / Re: The 2017 melting season
« on: July 16, 2017, 02:16:20 PM »
I think the heat is on now on the pacific side of the CAB. This doesn't look like a "mood" for me of the Bremen graph, there's too much green already.

No, this is real, Uni Hamburg AMSR2 shows it too. There's a lot of melting potential there, and given the 'piggy bank' ice in the Kara Sea, Laptev Sea and Baffin Bay, I'm expecting the series of JAXA century breaks to continue for a while longer.

Here's a comparison of DMI SST anomalies for 2012 (left), 2016 (middle) and 2017 (right) for July 15th. I would say that 2017 is well ahead of 2012 on the Pacific side, slightly behind on the Atlantic, and I'm somewhat surprised that no red still hasn't shown up in the Laptev Sea this year. The story for 2017 vs 2016 is the same, except that 2016's lead on the Atlantic side was much larger. But given the current forecast, with persistent high pressure on the Siberian side of the Arctic, 2017 might still catch up.

My impression that there is some sort of conservatism in how data is assimilated to the DMI model as compared to NOAA. There seemed to be an initial lag in temps earlier in the the other open areas, beaufort, ESS etc as compared to the NOAA chart before catching up. NOAA is now showing warmer than 0C in parts of the Laptev bite. Perhaps DMI will show a different reading soon. Kara on DMI showed a negatory anomaly not long ago, now bright red.  On the other hand NOAA's model just seems to make stuff up in places, like the 16C it shows near Svalbard

7
Arctic sea ice / Re: The 2017 melting season
« on: July 15, 2017, 02:30:44 AM »
Current DMI and NOAA SST anomaly charts. They are different in specifics but the general theme is the same - a lot of warmer water all around, especially on the Pacific side. NOAA's version has been getting particularly angry looking recently.

Still a few more weeks of serious insolation to crank those temps higher, and the remaining ice will be surrounded by a killing field,( as well as storm driver and source of anomalous snowfalls later on)

AS a note, at some point the link between NH snow extent and ice pack extent must be severed if a warmer Arctic continues driving anomalously high snowfalls in Siberia and Canada. At some point there will be icefree Ocean but still a lot of snow on land

8
Arctic sea ice / Re: The 2017 melting season
« on: July 11, 2017, 06:05:58 PM »
Once the pack in the Arctic itself starts splitting in chunks it can't be long to game over. Deep gulfs between arms went close last year.

Here is an area of low concentration ice stretching from the open water in Chukchi sea through to at least 81N on worldview  today.

9
Arctic sea ice / Re: The 2017 melting season
« on: July 10, 2017, 10:37:39 AM »
Thanks Darvince. Those are really helpful.

5 day GFS precipitable water for the Arctic
CLICK IMAGE


The air with the moisture that comes in over the New Siberian islands is very warm very high - here are rain forecast and 700mb temps for a couple days out on windy TV from ECMWF - 4C at 3000 m at this spot where 13mm forecast to fall in three hours - a lot of energy transfer

However unreliable and unverifiable the models are in the region, that has to be rain

10
Arctic sea ice / Re: The 2017 melting season
« on: July 07, 2017, 04:19:33 AM »
ECMWF/ Windy TV predict a lot of rain today off Northern Greenland, over 25mm in some locations. The forecast temp  there at ground level is 1C today (so surely its rain not snow?)rising to 4C on Sunday and 3C on monday. That can't do the ice there any good

The forecast for 4 or 5 days also shows another large gulp of atmospheric moisture entering the basin via the Laptev. with more substantial rainfall. It comes with a warm airmass at up to 10C at 925mb.

Large areas of the basin are going to see rain over the next 6 days, further conditioning it for destruction, and rendering the outlook from May meltponds irrelevant, in my opinion anyway

11
Arctic sea ice / Re: The 2017 melting season
« on: July 07, 2017, 02:13:35 AM »
Re GFS/climate reanalyser overcooking its arctic forecasts, the models rely on sparse and iffy data on the region. eg GFS sees SSTs up to 16.4C today at the Svalbard hotspot whereas ECWMF/Windy shows SSTs under 6C in the same place. That's a huge difference and makes me wonder what other dubious inputs GFS is fed

12
Arctic sea ice / Re: The 2017 melting season
« on: July 06, 2017, 10:09:09 AM »
The clouds have opened for a moment to reveal the last ice between Laptev and ESS bites, it won't last long.

Windy TV is showing a lot of rain in the next few days at various places - how much damage will 23mm of rain do?

13
Arctic sea ice / Re: The 2017 melting season
« on: July 05, 2017, 02:51:03 AM »
By popular request, the animation shows three more features tracked from the end of the 2016 melt season up to July 10th of this year. Some of them don't recognizably kick in until later in in the fall. The last frame shows initial and final positions (or the full track for point features).

Overall the fluidity is like 'someone' was swirling different colors of paint on a turntable in a freezer that got moved later to the greenhouse. It's very hard to discern the patterns of movement shown in older textbooks (pre-2010?) such as ice caught up for multiple years in a full Beaufort gyre, or transported linearly eurasia-ward by a Transpolar drift. (Note currents per se are not shown but rather currents + wind-induced motion.)

There'll be a lot of turnover before the season has finished. This is part of the reset mechanism that Oren mentioned up-forum by which piomas, hycom and others get a clean slate each fall to paint a known ice edge, large areas of open water and FYI with basic thermo, as otherwise persisting mistakes are melted and exported away.

[The animation should be animating but wasn't, even though it fell well within the 700x700 pixel and file size limits. The cure, as it often is, is to crop size down very slightly and save again.]

Thanks for these instructive anims.

Another interesting feature is the loop of thick ice that tracks from northwest of Ellesmore Is;and and out the Fram exit. The remaining thick ice has been squeezed in as primer for the garlic press once the NWP melts out

14
Arctic sea ice / Re: The 2017 melting season
« on: July 04, 2017, 03:28:36 PM »
SST anomaly on July 1st, 2012 vs 2017:

The Pacific side is worse this year which is maybe more important than the the big lead in anomalies in Kara sea in 2012.

15
Arctic sea ice / Re: The 2017 melting season
« on: June 26, 2017, 03:35:29 AM »
81 hour loop June 21-24, Chukchi Sea on the NW Alaskan coast.
Look at all that blue ponding on the right hand side. Small wonder the NASIDC area cratered in the Beaufort/Chukchi.

And the abrupt massaging of the ice edge into a smooth line

16
Arctic sea ice / Re: The 2017 melting season
« on: June 26, 2017, 03:05:57 AM »
Edit: err, having some trouble attaching images. Any tips? I took it straight from the hycom snapshot archive.
The image is probably too large. 700 x 700 pixels should work, width especially is a constraint, try to crop or resize.

There appears to be a certain amount of weirdness in how the site handles gifs. Oversize gifs usually will open in a separate window on clicking but some, like STA's demand to be downloaded for reason I don't understand. This can also happen with gifs under 700 pixels I think, one of 3 animations I posted of Chukchi, Laptev and ESS seas the other day but I haven;t had time or inclination to try to understand the bug or issue

17
Arctic sea ice / Re: The 2017 melting season
« on: June 26, 2017, 02:37:43 AM »
Bill, slightly OT but that means that the loss of sea ice in the Antarctic would have a greater warming effect per square metre, albedo wise, than the loss at the same latitude (north vs. south) in the Arctic?

There's no sea ice below 80S and very little below 75. Wouldn't this lessen the effect?

18
Arctic sea ice / Re: The 2017 melting season
« on: June 22, 2017, 05:06:04 AM »
A few gifs of the Chukchi, ESS and Laptev seas in recent days and there does seeem, as LMV says, to be rmelt ponds appearing across much of the Siberian side, and not just on  the fast ice

19
Arctic sea ice / Re: The 2017 melting season
« on: June 20, 2017, 05:53:56 AM »
In the ESS and Laptev seas meltponds have been appearing on the fast ice but not on adjacent mobile floes. The meltponds appear to be rapidly draining, sometimes they only appear to last a day or 2. So a bay in the eastern ESS where meltponds appeared on June 5 is now in a state of disintegration(first image). The region to its west was showing intensely blue meltponds a few days later, which also soon disappeared leaving a grey discoloured ice(?) within a few days, and is now beginning to crack up.

Now the Laptev seas has bright blue on the fast ice, but mobile ice beside it remains whitish(second image). Why, I don't know, but there is definitely something interfering with the appearance of meltponds.

As for cci-reanalyser rain forecasts, we are now in the season of above freezing temperatures in the arctic, DMI is showing above freezing avg temps above 80N, so if precipitation is coming down, surely it falls as rain except in those areas where it is freezing

20
Arctic sea ice / Re: The 2017 melting season
« on: June 17, 2017, 03:16:41 AM »
If that bomb cyclone eventuates - and its still a long way off - there will be widespread wind including in the Bering, accelerating the inflow of warm water,  and Chukchi seas creating waves, as well as around the cyclone itself . It also drags very warm air in from Siberia. According to GFS 12z run

It is a long way off so unlikely to play out this way, but I posted the image because it seems remarkable for its "oceanic" windiness - a sign of things to come?

21
Arctic sea ice / Re: The 2017 melting season
« on: June 16, 2017, 09:26:26 AM »
The circulation around low pressure systems entering around the Laptev is driving the cold from the residual snow into the Kara and Barents Seas where it can't do much good. Over the next week on climate reanalyser those seas are consistently below freezing whereas the rest of the Arctic will see above freezing temperatures

22
Arctic sea ice / Re: The 2017 melting season
« on: June 14, 2017, 04:42:08 PM »

I believe in the experiment the fissures sealed after the third melt, the first two times the melt water drained away, more slowly the second time.

Thanks. That makes sense and is believable. However, if whatever caused the cracks and fissures  from the beginning causes new ones, then the process resets. If it had been waves vs thin ice, the waves will probably win in long run, as they seem to be reaching deeper into the Arctic now.

Also there are no 100km floes in areas with any dispersal, maybe some 50km in the Beaufort sea, with the odd 10-20km solid floe  in sea of mush elsewhere

23
Arctic sea ice / Re: The 2017 melting season
« on: June 13, 2017, 04:28:18 AM »
I wonder how much of the sea ice anywhere in the Arctic has enough freeboard to allow for melt-ponding. Obviously, everything is whiter this year, but it may just be because there is not much more than snow above the water. If someone has some pics from here and there, they can easily shoot down that supposition.

P.S. A little tangent to this discussion; check this out.
www.bbc.com/news/av/world-europe-38562814/parts-of-greece-have-been-blanketed-in-snow




Photos a few days ago of ice in Fram Strait pushed below the waterline by thick snow don't fill me with confidence. Melt ponds aren't so important if the sea can wash over, especially with fragmentation and dispersal. And all that snow would have retarded thickening when the weather got cold at the end of winter.

SSTs will drive momentum. Anomalous warmth is appearing almost everywhere with the exception of southern Baffin Bay and the cold pool south of it in the Atlantic which . There are some pretty outrageous temperature gradients to fire up the cyclone cannon later on -

24
Arctic sea ice / Re: The 2017 melting season
« on: June 12, 2017, 05:08:50 AM »
This cloudless image from june 10 shows areas of "grey mush" between the large, and bright white icefloes in the Beaufort. What is that stuff?

25
Arctic sea ice / Re: The 2017 melting season
« on: June 12, 2017, 04:44:49 AM »
My apologies to the users, I uploaded the wrong gif. I deleted that post. Here is the one I wanted to share.

This is in the Chukchi Sea area. In 2016 the pack seems a blueish tinge while in 2017 it is completely white. I think the blue is either melt ponds or maybe just ice without snow cover. To me the whiteness of 2017 signals a good amount of snow. I think that is a good sign.

With the absense of meltponds so far t least there is one factor retarding melt. But the 2017 image is still much darker because of all the open water - There's also a lot of ice on the Siberian side that appears greyish, all along the margin of the fast ice and has for months, maybe because its very thin and fractured. I fear absence of meltponds is not going to be enough to save the situation

The 2 images are from june 11 - even if the coast remains ice bound open water has appeared beyond the fast ice already along much of the northern route

26
Arctic sea ice / Re: The 2017 melting season
« on: June 10, 2017, 08:59:30 AM »
Melt appeared immediately in the open water from FJL through the Barents Sea so bottom melt must be going on nearby as well, there's been a fair bit of wind in the region. The image is from June 9  -edit: this area is still showing as solid white on the NSIDC extent chart despite the totally open strip being over 50km wide!

There's also strong wind forecast in the Chukchi for the next day or 2 which will keep the ice retreating

27
Arctic sea ice / Re: The 2017 melting season
« on: June 06, 2017, 03:45:56 AM »
It's windier over sea water than ice.

The climate reanalyser/GFS forecasts seem to have been showing  a correlation between the open areas and increased windiness recently. (despite those waters still being near freezing, so I'm not sure how seriously to take it) The latest 12z run it shows at least 30kmh wind all week in the open area in the Chukchi Sea, blowing at the ice, and peaking around 60kmh about 5 days out. The forecasts are garbage that far out of course

A low is also forecast to head into the basin over the  New Siberian Islands in about 60 hours, whose winds intensify, again to around 60kmh, as it heads over the open water nearby. I guess we'll see if this plays out.

Extra waves hammer the ice, but also mix warmer water from below feeding back into more wind (?)

28
Arctic sea ice / Re: The 2017 melting season
« on: June 06, 2017, 02:34:26 AM »
Despite the persistence of snow cover in Siberia there appears to be at least some meltponding on the fast ice in the ESS. This image is from June 5
I may be misreading what your arrow is pointing at but some of those dark patches are cloud shadows. The 7,2,1 bands on worldview are very good at showing up surface water (dark blue) and clouds (white) against snow/ice (light blue)
https://go.nasa.gov/2rL5eoV
meltponding on Chaunskaya bay was stronger at this time in 2016 and 2015 (by a few days) and more extensive along the coast to the west, where it is still absent at this time.
Snow cover on the land near the bay started to clear some time ago but lower temperatures have slowed this down. The rivers flowing into the bay are nevertheless starting to pour water onto the ice (small dark patches are appearing). To see developments in previous years look for the "Siberian coast " thread.
The feature which will make a difference there is the open water in the ocean off the bay which is absorbing much more sunlight than the ice cover.

Yes there are some clouds, but there is also some blue, which indicates melt [edit: or liquid water at any rate whether fro in situ melting or flow from the land] - I'm not suggesting it is stronger than some other year.

I have to agree that is the open water that will have more effect

29
Arctic sea ice / Re: The 2017 melting season
« on: June 05, 2017, 08:46:39 AM »
Despite the persistence of snow cover in Siberia there appears to be at least some meltponding on the fast ice in the ESS. This image is from June 5

30
Arctic sea ice / Re: The 2017 melting season
« on: June 03, 2017, 03:41:33 PM »
Ice in the Laptev on 2 June near the New Siberian Islands. There appears to be a large amount/area of floes smaller than the 250m resolution if the imagery - the grey mush.

Also appears to be some melting around the 'mouth' in the silhouette between water and ice

31
I hope I'm wrong but I've gone a bit out on a limb and plumped for 2-2.5million km2. It's really just a stab in the dark, but given the current low volume and thin dispersed ice I'd be surprised not to see a new record low, and if conditions are really conducive less than 1 million km2 can't be ruled out  - so I went for somewhere in between

32
Arctic sea ice / Re: The 2017 melting season
« on: June 02, 2017, 05:04:00 AM »
The hotspot at Svalbard is getting hotter - the warmest temp I could find today on nullschool was 12.5C, yesterday it was 12.0, a week or so ago around 11. The other green patch south of Svalbard is up to 8.3C

Nares strait SSTs are over a degree warmer than Baffin Bay at around -0.5 or -0.6. Even the water just north of its inlet between Ellesmere and Greenland is at -1.5C which seems surprisingly "warm"

33
Arctic sea ice / Re: The 2017 melting season
« on: May 30, 2017, 03:22:25 AM »
From the previous post

34
Arctic sea ice / Re: The 2017 melting season
« on: May 30, 2017, 03:06:05 AM »
The very heavy snowfall held out through May slowing the predicted May decline in the 50 day sea ice model. That snow is almost gone in north America now so I think the melt rates are going to start reflecting the model prediction soon. Siberia is warming up fast, but has more snow to melt. For predictive purposes it's probably better to smooth that curve out instead of predicting a cliff, in my opinion. But we all know how hard it is to predict the weather so let's not get overconfident in forecasts. No matter how we look at it, the forecast for the ice looks bad.

The GFS may overcook snow melt, but for what it's worth here's the forecast loss over the next week. It may be too aggressive, but if the forecast heat materialises in Siberia the snow can't last much longer there.

edit: - I added the attachment I'd had forgotten, and the replaced with one that will play /edit

With the state of the ice on that side and a series of lows in the Kara Sea blowing into the Barents and sucking warm moist air in, more and more open water will appear and start warming. Does the ongoing weather setup of a high surrounded by lows cause rotation and compaction of  the centre, while lows disperse ice at the edges? With the mobility and fragility and thinness could the pack become entirely separated from the margins of the Arctic Ocean, or even split into pieces rather than develop arms.

If the summer is sunny and the Ocean takes up a large amount of heat, then the autumn turns stormy like last year the minimum could come very late. During the winter on the freezing thread it was suggested(if I can trust my memory) that when we go sub 1million km2 sometime in the next few years, it could happen in October.

It's too early to discount the possibility of going icefree this year. Things have started ominously. We just have to watch what unfolds

35
Arctic sea ice / Re: The 2017 melting season
« on: May 29, 2017, 05:18:28 AM »
Wipneus posted a nice animation today in his Home Brew AMSR2 thread, showing the torching in Beaufort:




30 days in the Beaufort to May 28 from worldview showing - disintegration. Will dispersion everywhere continue to keep extent numbers deceptively high in the next weeks?

As well as the gif I've included jpgs of April 29 and May 28 - at the resolution I downloaded ~1600x1600 - the gif convert produced at this size was 100+MB. If anyone can point me in the direction of a movie format that supports arbitrary frame sizes please do - over on the gif thread http://forum.arctic-sea-ice.net/index.php/topic,1259.0.html


36
Arctic sea ice / Re: The 2017 melting season
« on: May 28, 2017, 03:08:00 AM »
Above the CAA clockwise rotation of the pack teases open the cracks and opens more big leads at the margin of the fast ice. This view shows the north west of Ellesmere Island (at bottom right) and the Islands to its west

37
Arctic sea ice / Re: The 2017 melting season
« on: May 27, 2017, 08:19:09 AM »
Subtly things are opening up. So slow, you barely notice one day's worth; but add a few days together and, voila!


Clockwise rotation of most of the pack, and a bulge of further export to Fram keeping up extent, but that ice loss will be felt later.

Here are a couple of gifs - one of Fram Strait over the past couple of weeks and the block smash in Nares strait.

I've published a bit of python code for retreiving sequences of worldview images over on the gif creation thread - it's already helpful but its just a snippet so far http://forum.arctic-sea-ice.net/index.php/topic,1259.msg114906.html#msg114906

38
Developers Corner / Re: Creating Animated GIFs
« on: May 27, 2017, 06:52:36 AM »
I'm starting to write a bit of python code to ease downloading of image sequencies, initially from worldview, but the approach could be applied to other sites that encode params in the url

It's just a function so far which I've been using in the interpreter. Basically you feed it the url worldview's image download function loads and python downloads it and a sequence of previous days(the default is 8 ) and writes them with a series of sequential names(based on a nameroot you can give, and which defaults to "worldview")

When I have another free hour or 2 I'll add argument handling so it can be used as a script

import urllib, urlparse

def get_worldview_sequence(start_url, count=8, outfileroot="worldview"):
    parsed_url=urlparse.urlparse(start_url)
    startquery=urlparse.parse_qs(parsed_url.query)
    #this will cause problems when going over the new year
    #but its quick so we do for now
    startday=int(startquery["TIME"][0])
    while count >0:
        #this really should check that
        #this doesn't get to day 999 of the previous year or other nonsense
        startquery["TIME"][0]=str(startday)
        realquery={}
        for nm in startquery:
            realquery[nm] = startquery[nm][0]
        #fucked up character substaitution
        out_url=urlparse.urlunparse(urlparse.ParseResult(parsed_url.scheme,parsed_url.netloc, parsed_url.path, parsed_url.params, urllib.unquote(urllib.urlencode(realquery)), parsed_url.fragment))
        #out_url= "https://gibs.earthdata.nasa.gov/image-download?"+urllib.urlencode(startquery)
        outname=outfileroot+str(startday)+".jpeg"
        print out_url
        urllib.urlretrieve (out_url, outname)
        count=count-1
        startday=startday-1

39
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 03:53:37 PM »
How long till the northern route opens? Days?  ;)

 If you look in Worldview it's floes interspersed with rubble the whole way, out beyond the land fast ice, not to mention the open water appearing. And the ice  appears very thin

40
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 03:30:23 AM »
Fracturing extends right across the pole . This is a worldview image for May21 when skies were clear from 82.6741°, 89.5667° to  84.7954°, -133.7105°

I've darkened the image in levels to accentuate the cracks

41
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 03:02:06 AM »
It seems the first-year ice bowl has just about arrived at the north pole, this feature has been pretty easy to track on the HYCOM 365.
https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim365d.gif

Judging by how mobile the surviving ice was last fall/winter, it looks like first-year ice from the Laptev sea all the way to the pole.

Even the thicker ice exiting to the Barents near Svalbard is totally fractured. It's like a new kind of preconditioning for dispersion and ultimately melt.

The gif is the area from 80.5618°,37.7858 to 81.8470°, 27.3577° which is an area just north of a line between Svalbard and FJL form May 22-4. I've repeated May24 as the first frame as it's cloudfree

42
Arctic sea ice / Re: The 2017 melting season
« on: May 20, 2017, 09:28:32 AM »
Previous GFS  forecasts of rain turned to snow as they got closer - anyway GFS is now predicting a pair of deep lows - both bottoming in 970s- to enter through the Laptev Sea from about 5 days out with above freezing temps, strong wind and and copious rain. The first slings the second right out across the basin. It's a way off so hopefully it won't eventuate

43
Arctic sea ice / Re: The 2017 melting season
« on: May 20, 2017, 08:51:31 AM »
The way the ice disintegrates now, I suppose before long, it will find its way out of the Arctic through any little nooks and crannies that open up. This will be a summer of, not just melting, but extraordinary export.
This is a possibility, but not certainty, IMO. Another possibility exists: despite much increased mobility, most ice which "could" be exported - will not be exported, "running" circles within the Arctic instead, being compacted much in the process, too. I mean, if weather will change to provide that in like, say, 2 weeks, and will remain in this "making ice to go circles within the Arctic" for the whole melt season. It sure would be a surprise, of course, if this happens; but on the other hand, we had lots of surprises of various sorts last few seasons, starting with 2012's GAC, you know.

But here is nothing t hold the ice in especially on the Atlantic side but also through the garlic press and Bering, the Bulwarks have failed. Surely the leads to less compaction and more export as well as more mobility generally, especially with consistent winds into the Barents and out through Fram - where ice is chugging along at a good pace as can be clearly seen on worldview

44
Arctic sea ice / Re: The 2017 melting season
« on: May 19, 2017, 04:49:13 AM »
RE cracks, I was looking around 83N on Pacific side for a strip that Bremen showed as low concentration a couple of days ago and there are fairly regular parallel cracks in 2 directions. In Gimp's levels I pulled in the black point to accentuate the cracks. I've include the same area and date for last year, with the same processing. It shows a lot of cracking around the opening in the Beaufort, but less further into the basin

Looks interesting alongside  Jai's image of cracks aligned to directions of motion and stresses in Lincoln Sea. I've no idea if the 'periodicity' is significant(perhaps the pack is being stretched as much as squeezed these days?) but it does suggest a pack that will be more easily dispersed

45
Arctic sea ice / Re: The 2017 melting season
« on: May 17, 2017, 01:04:04 PM »
Wherever dispersal is possible the ice seems ready to break along a grid of fracture lines, kind of fractal in that the lines of differently spaced from area to area in a region. I've added an image from around FJI on may 13 which reminds me a bit of the spectacular "tyre treads" posted by ATeam etc on the freezing season thread after a storm. The worrying thing is how the fracture lines can be seen continuing into the pack as it is fed into the Atlantic.

Similar features can be seen on the Pacific side which is what prompted me to post the question of how deep it goes. On the Eurasian side only the landfast ice has any large scale integrity, and presumably thickness, but the winter cold of nearby continent is now raplaced by summer heat. Once September goes close to ice free will ice l struggle to cover the basin from the edges? Hudson Bay might freeze better than the Arctic Ocean?

46
Arctic sea ice / Re: The 2017 melting season
« on: May 16, 2017, 04:22:34 PM »
Ice around Wrangel Island is no pack but a sea of ice cubes. Will we see the same in the central basin as the season progresses?

47
Arctic sea ice / Re: The 2017 melting season
« on: May 15, 2017, 01:46:21 AM »
In about two days' time, the first Arctic Basin storm of the 2017 melt season will also provide the first test by wind for the allegedly thin ice in the Laptev Sea. It's forecast to bottom out at about 984 hPa. Nullschool...

'Allegedly' thin ice in the Laptev has put on a sad face in anticipation   8)

48
Arctic sea ice / Re: The 2017 melting season
« on: May 12, 2017, 03:22:40 AM »
Meanwhile, jaxa May 10 extent up by 15,000 km2. That is 10 days and very nearly 700,000 km2 behind 2016, and 5th lowest in the satellite record. And yesterday AMSR2 volume ticked up a bit. That is a lot to make up in the remainder of the melting season.

On the other hand, the latest from robertscribbler.com confidently predicts significant arctic warming events in the next few days, and ASIF is full up images of the mess the ice cap is in.

But as of today as far as extent is concerned 2017 is a very ordinary year.

New ice forming in the many leads opening would add volume, added to all the volume being shunted into the Barents and Atlantic which hasn't melted, yet

49
Arctic sea ice / Re: The 2017 melting season
« on: May 10, 2017, 03:49:43 AM »
The heat wave in Eastern Siberia is going to be memorable in a week and for a week, if the CFSv2 and GFS and ensembles realize, (and the CFSv2 has been working really well,  and btw has been predicting this for weeks).
Alaska and parts of Canada/CAA too. Wall-to-wall

It will be interesting, to say the least to see what unfolds around the area of open water in the ESS in this worldview image from May 9. GFS is already showing that small area remaining at or just above freezing dispite colder temps all around and the heat is about to start today.

Each wave of heat over the next week in the forecast sends  a band of rain right into the heart of the basin - and at the end of tuesday 12Z run there's suggestions of a third

50
Arctic sea ice / Re: The 2017 melting season
« on: May 05, 2017, 10:53:52 AM »
Stunning aprupt upwards movement of the Extent Graph of Bremen...  :o



pretty dramatic hey. Their map has a lot of missing data today as well

But the reality is not a lot better, here are a couple of worldview animations of the ESS from april 30 to may 5, a wide view and a closer one of the region from70.6260°, 178.126V to 70.5408°, 173.1176°

You can see floes drifting and rotatingat different speeds according to the local ice concentration eg with the 2 large floes at top left of the wide view

 This is part of the area forecast by GFS to see above zero temps starting about 4 days out and intensifying. I don't know how significant it is but a modest low is forecast to form in the area and proceed across the basin to the pole bringing snow and rain in its wake

Pages: [1] 2