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Messages - subgeometer

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1
Arctic sea ice / Re: The 2019 melting season
« on: Today at 05:10:30 AM »
The DMI volume chart is hopeless, at best a week or 2 out of date. It's showing a ice over half a meter in open water in the Laptev bite today, and great swathes of ice in Baffin Bay in these 2 maps dated 16 July from Bremen and DMI - though what date the DMI really refers to, who knows

I've attached the comparison as both a gif(click to and an mp4. The MP4 plays fine locally but its been a bit of a lottery trying to get them to play on the forum, at least in my browser

2
Arctic sea ice / Re: The 2019 melting season
« on: July 17, 2019, 09:57:57 AM »
A lot of the cloud on Worldview today is thin enough to peer through, and wherever you look ,from the Pacific to the Atlantic across half the basin, is dispersed ice,and  in many areas showing telltale signs of melt

I've attached images of 2 areas, colour coded 2 match  with the squares at 77 and 81 N in todays Bremen extent map

Edit: I forgot to add that the images have had the contrast enhanced by monkeying around with levels in Gimp

3
Arctic sea ice / Re: The 2019 melting season
« on: July 17, 2019, 02:30:30 AM »
Holes are developing all over on the Eurasian and Pacific sides as dispersion takes its toll and areas of FYI start to melt out.

The area shown is about 84-85N, north of the Laptev Sea, and a few hundred km from the Atlantic Front. If I can find time I'll have a closer look with Sentinel as things progress

4
Arctic sea ice / Re: The 2019 melting season
« on: July 15, 2019, 01:16:05 AM »
The Lincoln Sea is pretty warm the next couple of days as winds blow up Nares strait and off Greenland etc. Those  huge areas of bare rock must drive a lot of thermals, adding turbulence, as well as more heat to the foehn wind this area is subject to?

I've added the Windy forecast for about now, as well as a Worldview image of the area yesterday

5
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 07:15:10 AM »
More greying ice in the ESS

I copied the cloud free area in the square in gimp, resized the image to one pixel, then looked at the level, which is 107.

In 8 bit graphics mid-grey is 127 or 128 (0 is black and white 255), so this ice is closer to black than white.

Naively dividing 107 by 255 to get a value in the range from 0 to 1, that comes out to an 'albedo' around 0.42 That ice is pretty good at collecting light energy, Given the ice darkens as it deteriorates, it's going to accelerate the final meltout of that and similar areas.

The pack is nowhere as grey as this coastal stuff, a, but its visible greying after melt onset gives an extra kick to insolation potential(moreso in bad years), and there is a long stretch of seas off the Russian coast that can collect continental dust etc

6
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 07:49:36 AM »
The ESS former fast ice ice is in no shape for the blowtorch its about to go under. Nor is the Laptev ice which is extremely grey, and collapsing now. A lot less cloud on worldview today

7
Arctic sea ice / Re: The 2019 melting season
« on: July 06, 2019, 06:54:21 AM »
Currently it's 21C at the weather station at Niuqsuk Airport, just east of Barrow,  with the dewpoint at 11C, with the breeze blowing straight out onto the sea
Those dewpoints mean the ice will be literally sweating the moisture out of the air even without rainfall, with the attendant transfer of heat.  Same applies to any open water as well, assuming SSTs of around zero.

Windy says that, right now temps are up to 25C on Wrangel Island, with similar maximums each day.

(Like the temperature) the dew point drops once the air gets over the ice(3C at the surface, it rises to 6C at 950hPa and 8C at 925, at the pt indicated), but a large and increasing area will experience dew points of 2-4C in the days(and days) to come.

I've attached bunch of screenshots from Windy to illustrate, of surface dewpoint, temperature and humidity. as well as clouds for daytime on the 8th(ie 2 days out). 3C dewpoint, 4C temp and 98% humidity, which as it turns out is predicted to mark the edge of clouds - a lot of ESS ice will be undrr full sun as well. This is going to be interesting to watch

8
Arctic sea ice / Re: The 2019 melting season
« on: July 05, 2019, 02:43:42 AM »
For the next few days, at least, high pressure and warmth dominate from Kara through the central CAB to the CAA/eastern Beaufort. These are the parts of the Arctic that have been relatively protected so far, and now they will be exposed to surface melt/melt ponding and high insolation.




I think this pattern will be bad for the ice. The southern Laptev and ESS are already in such bad shape that they will melt out anyway over the next few weeks, particularly with the help of warmish river water, while Chuckchi and the western Beaufort have the high SSTs and southerlies through Bering to contend with. Add in continuing Fram export...

Beyond this, the models seems a bit unsure whether high pressure will dominate the whole central Arctic or whether the high pressure will drift across to the Eurasian side, allowing a low to develop over Beaufort, creating a reverse dipole.

Based on the emerging pattern, I expect high losses for the next 2-3 weeks, but I wouldn't dare to predict whether they will be steady or occur in fits and starts.

Its not just the rivers. The areas under cloud may be protected from sun, but temperatures are high, and the precipitable moisture levels are nuts - not much of an arctic desert this week coming. One huge blob of moisture is being pushed from Eurasia via the Kara to rotate north of Svalbard, with surface temps around 2C, while the Alaska and Chukotka heatwave pushes warmer air and more moisture in from the Pacific. The melt over the past few days has been very aggressive on that side as we see in the Bremen animation, and that's only going to continue, if not worsen. (Warm?) rain and a lot of longwave radiation, as well as very high SSTs close by

I've attached 5 day GFS forecasts for NH max(cor blimey, that's a lot of red) and avg temperatures, as well as precipitable moisture and rainfall(precipitation, ~20mm in places, but not much will be snow).

9
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 06:50:36 AM »
The darkening of the pack thru June is pretty stark in this movie. of worldview images. I've also attached the June 1 and June 30 for comparison.

We need a lot of bright white cloud

Edit: replaced the movie with one half the size to see if it displays the Atlantic side on the page

10
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 03:25:02 AM »
Talking of longwave radiation and latent heat: there is a 30kg/m2 river of moisture flowing in through the Bering Strait all week, and the air column will be warm, freezing altitude varying from ~2000-3500 m over the Chukchi sea according to Windy( the freezing altitude map is nuts right now). The clouds thicken and cloudbase drops as the air hits the ice edge.

Surface temps at the spot indicated stay around 6-7C (dropping to 2C over ice) through the forecast, and the air above is about the same temp or slightly warmer up to around 900hPA and about 2C at 800hPA. Wind from the south, a 15knot breeze at the surface, about double that aloft

Does anyone have an idea how much of that moisture is arriving at the ice edge as vapour? How much latent heat is being transferred to the ice?

11
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 02:40:55 AM »
A quick and dirty insolation calculation could made by making a grayscale version of Worldview's truecolor image for the date, ...

It would definitely be quick and dirty.  Gerontocrat was not kidding when he talked about the cost of developing a model that would accurately account for the cloud effects on albedo. 

Clouds are very, very, very complicated.  They are all different.  Different clouds let in different wavelengths of light that have different energy.  Different clouds also block upwelling wavelengths of light and reflect them back to the surface.

There are many papers on this topic.  The take home message is that it is not a simple matter of saying it’s cloudy so the Ice is protected.  Sometimes the clouds make things worse.

Sure, clouds are complicated, hence the desire to not have to handle them

My suggestion is for a method to calculate raw insolation, not longwave and other processes. Quick and dirty, but also simple. My thought is that the whiter clouds are, the more sunlight they reflect,

12
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 04:06:33 AM »
Laptev SSTs are now up to 10C in the bite according to WindyTV/EC. Most of the open water is between 6-9C. (Around the Lena delta water is an insane 17C). Have SSTS ever been this high there? Let alone on 27 June? For the next few days winds turn around and start blowing ice from the north into those warm waters, while the Chukchi will warm up some more as Alaska heats up.

Meanwhile half the basin is above freezing at the 800hPa level, all week long(The CAA, and adjacent areas of CAB, as well as the Kara Sea, the Atlantic front all take a clobbering) Even where the lows are its barely freezing at this height(2000m)

My personal not really scientific(though testable) theorem is that when a sea ice region starts looking like a head, its the beginning of the end for it, soon to distort, fall apart , and ultimately melt. We've all seen the baby elephant head that forms in the Chukchi sea the past few years. The mouth widens, the trunk narrows, and then, ... poof. The southern Beaufort starts out with more human features. So it's been with growing alarm that I've watched the whole Pacific sector take on the appearance of a bearded face in recent days.

13
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 07:05:15 AM »
Volume is key for us here maybe, but I wouldn't write off 2D measurements as necessarily secondary for everything. Eg in its effects on the the weather and climate, extent/area measures  (where ice is) are the key thing. That sets the albedo, in part determines location of the jetstream, etc

14
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 06:24:24 AM »
Focussing on "the numbers", as you put it, is an example of the streetlight effect. Area and extent are useful in sometimes indicating anomalous regions, regions where one might want to try to figure out what's happening, but nothing more. (Obviously just my opinion.)

Really it just comes down to the weather now.

Area and extent are imperfect indicators, but at least can be directly and fairly reliably measured, unlike, say, volume. Area and extent numbers and maps from the various outfits that produce them (NOAA, uni Bremen, Jaxa ...) stay in general agreement while what volume maps exist are much more idiosyncratic.

Changes in area and extent have to be read in context - time of year, weather conditions, the quantitative(eg thickness) and qualitative(eg solid pack or loose rubble, rottenness) state of the ice. JAXA flatlined because of ice export and dispersion from June12-16 (losing only 40000km2 of extent in that period) while the weather was terrible for ice and volume was clearly taking a hammering - all those deep blue meltponds, and the huge amount of wet ice that appeared around then.

These are subjective and complex judgements to make for anyone. Its easy to get (maybe over)excited by some event. especially for us interested newbies with only a few or less seasons under our belt.

Speakin' of exciting, here's an area of the ESS in meltdown over the past week(the big bay just to the west of the centre of the ESS coast), under heat and full sun at solstice, including plenty of in situ melt. I've also attached an image of the whole sea today

15
Arctic sea ice / Re: The 2019 melting season
« on: June 23, 2019, 07:44:37 AM »
JAXA is down 180K km2 over the past 2 days ending a week of limited losses in extent. All of the gap and more with 2016 can be accounted for by high extents in Greenland and Barents Seas, ice exported to doom. The Kara Sea is also high, as is the CAB itself, because the exits to the Atlantic are kept loaded by the northerly winds;

The Beaufort sea is still very low for the date, despite the recent uptick. The Chukchi and Laptev seas are also around record low. The Siberian coastal ice will collapse within days, the next 4 days are a blowtorch

16
Arctic sea ice / Re: The 2019 melting season
« on: June 21, 2019, 02:25:27 AM »
Last 2 days, NE Greenland coast has some fast ice breaking free.  Lots of neat swirls as well.

http://rammb-slider.cira.colostate.edu/?sat=jpss&z=3&im=42&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i01&x=17859.759765625&y=13706.57421875

That swirl of currents and melt is where the extra warm plume of Gulf Stream water (on the DMI SST chart)hits the sea ice. That persistent polynya against the coast near where the fast ice is cracking uphas been open for months again, and no ice can survive within it during summer, eg the jiggling blob of melting ice poking in on the north side appears to be going fast, like a blender is stirring it from beneath

Edit: One thing I've been wondering(and its a bit OT so I'm happy to be directed to another thread) is at what water temperature does sea ice begin to struggle to form  a freezing fresh boundary layer as it melts at the bottom? Ice in Boiling water, or water hot enough for active convection is surely not going to behave that way until substantially cooling the body of water. But what about water that's over 4C, where water is densest. Cooling 4C water to 2C makes it more buoyant, cooling 6C water to 4C has the opposite effect. Does this have any significant effect in diluting and mixing the boundary layer, and exposing the ice to more heat?

17
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 04:01:11 AM »
Michael Hauber. If there's a real increase in area in the Beaufort Sea it came from elsewhere, there's no new ice forming. It came from the CAB, which hasn't had an area reduction, so trhe concentration has to have decreased. To be counted as area a grid square needs to contain at least 85% ice, so in an extreme case area could go up 15% with no real gain.

The pack in northern Beaufort and adjacent CAB loosens(but is still>85% ice), et voila, unreal area gains

The collapse over the Siberian shelf, if it happens rapidly, could create the same effect

18
Arctic sea ice / Re: The 2019 melting season
« on: June 17, 2019, 06:25:46 AM »
The storm has further fractured the pack north of FJI, which was already looking fragmented with a lot of open water between floes.

The Uni Bremen extent map shows dispersion artifacts around 86N, north of FJI so I tried to have a look. Too cloudy as yet for worldview, and Sentinel appears to have a large pole hole, so I went about as far north as I could get (82.6, 51.85)It's way too cloudy even for sentinel to get enough images for animation, so I've included images from the 11th and today, along with an image of a minimum scenario which would challenge 2012. In short I think the Laptev bite, could go way north, with lots of ice flushed into the Barents and Atlantic.

If the weather continues bad in most sectors, and then a compaction event, (like 2012 I think) pushing ice onto north west Greenland and the inner CAA without the garlic press going overdrive,the min could challenge the record

19
Arctic sea ice / Re: The 2019 melting season
« on: June 15, 2019, 01:32:41 AM »
The low pushing the ice south in the Beaufort, is also pulling the edge of the CAB north, starting to peel it away from the CAA in the past 2 days. The animation shows june 12-14 on Worldview.

Edit: fixed CAB/CAA garbling

20
Arctic sea ice / Re: The 2019 melting season
« on: June 14, 2019, 02:59:42 AM »
20C now on Wrangel Island, doesn't drop below 10C at the location selected until Wednesday evening, and according to my quick calculation, the average until then is 14.5C. Its sunnier than the surrounding ice(though warm humid air under cloud will seed surface melt, so may be no better). The Laptev is is for full sun the next couple of days
and the Chukchi sea will continue warming as well

21
Arctic sea ice / Re: The 2019 melting season
« on: June 07, 2019, 03:54:07 AM »
Windy 900 hPA forecasts showing huge mass of warm air entering the basin, as discussed in the previous post

22
Arctic sea ice / Re: The 2019 melting season
« on: June 05, 2019, 03:24:40 AM »
DMI temperature north of 80N reached zero.

Wow that was fast. Thanks for posting that - I only check every few days or so.


 a full 7 days ahead of schedule .. it takes phenominal energy to lift temperatures in this area a full 1'C above normal at this time of year . The current GFS run is a little cooler but still has the pole above freezing throughout the next 8 days . The weighting of the measure toward the pole may well help keep it in record territory .. b.c.

Of recent years 2012 is the only year to jump to 0C this early [plays Gothic music]. 2007 by contrast lagged well under the line at this point, and most years recently have gone be;ow the average once it reaches  -7C or so, The onset of melt constrains the temperature. A more fragmented pack has higher surface area available for melt perhaps.

Anyway an extra week at or above 0 can't be good news. I've attached 2012 and 2007 DMI 80 north charts, as well as 1990, another year where summer came early

23
Arctic sea ice / Re: The 2018 melting season
« on: August 02, 2018, 03:52:35 AM »


Does the setup of the past months resemble a two-cell system instead of the classic three-cell system setup in the NH? If it stays like that also for the winter, what are the consequences?

The way the lows were repeatedly ratcheted into the Arctic seas, attached to troughs drawing hot air from the mid latitudes suggests the Arctic cannot keep itself separated from the lower latitudes. As a relative newcomer here I don't have a sense of how new or unusual that is, when time permits I'll try to find reanalysis of previous summers for comparison(Climate Reanalyser publishes the whole years worth at the start of the new year).

JAXA is offline for a few days. Arctic ROOS' ssmi is now showing extent at record low since a couple of days ago, just at the time the recent years begin to diverge(area starts doing the same about a week or 10 days earlier - on ROOS, area is still relatively high, a week ago it was highest for the decade!). 2012 started its big plunge a few days further into August. Interesting times.

Arctic ROOS is at https://arctic-roos.org/observations/ice-area-and-extent-in-arctic

24
Arctic sea ice / Re: The 2018 melting season
« on: July 28, 2018, 08:01:02 AM »
a week in the pacific sector -with a higher res still of the most recent day(yesterday). That area will continue to cop a beating

25
Arctic sea ice / Re: The 2018 melting season
« on: July 11, 2018, 07:37:34 AM »
There are intriguing swirls of brown ice along the Siberian coast. The tongue along the Chukotka coast went really dark as it melted out. It's hard to see much of the ice around Wrangel Island at the moment but it doesn't seem like it willlast much longer - this is an area south west of it on 11 july worldview

Jaxa has gone back to very small losses, 20K and 50K in the past 2 days. We're going to see some big single day drops at some point if this goes on much longer, even if the minimum ends up on the high side

26
Arctic sea ice / Re: The 2018 melting season
« on: July 10, 2018, 02:36:49 PM »
Lows acting like cogs drew in massive amounts of atmospheric heat over the past weeks. The low forecast now is kinder as cold deveops over most of the basin at 850mb for the next week but all the peripheral seas - Laptev, ESS , Chukchi and Beaufort are all subject to further warm intrusions from the south, while the Kara and Hudson Bay will be basking in heat, so they should melt out soon. The area a low can protect has maybe shrunk a bit

ECMWF sees that cool airmass being blown asunder in a week or so by another influx, this time frtom the Atlantic, who knows, but it would not surprise.

Glue ice is starting to melon t out in the southern Beaufort, and after the mini-GAC small gaps are appearing distressed ice as far north as 81N on that side. Blue grey and brown discoloration is visible from Svalbard around the whole periphery and far into the pack, so we may be in for some drama yet even if this is not THE year


27
Arctic sea ice / Re: The 2018 melting season
« on: July 01, 2018, 05:40:20 AM »
Ice off Svalbard that has been pushed  half a degree south to its imminent doom - see the broad area of grey mush dissolving into skeins at the front. It's a beautiful image so I've included it at full 250m resolution, with a detail cropped from it

28
Arctic sea ice / Re: The 2018 melting season
« on: July 01, 2018, 05:24:39 AM »
the trough and front systems rolling along the Siberian coast are dragging in insanely warm air especially over the Laptev, which forecast to be up to 26C(!!!!) at 950hPa on Thursday, accompanied by serious rainbands, with much of the Laptev to see rain with one area seeing 40mm in the next 3 days. The low being drawn in drops to 972 as it heads for FJI and stays there  for a day or 2, drawing warmth from Siberia, and pushing the ice front into the Atlantic killing zone;

I haven't had a chance to read the discussion over the past few days, but I agree with bbr that the June weather hasn't been great for ice despite the slow extent loss

edit: I just had a look at the surface temperature forecast for thursday - still over 4 days away, but a prediction of 10C well onto the ice is pretty spectacular - just how quickly will that melt it?

29
Arctic sea ice / Re: The 2018 melting season
« on: June 24, 2018, 05:00:45 AM »
Algal blooms are visible fed by the flood plumes of rivers flowing into the open water along the coast south of Wrangel Island. Lovely clear skies to maximise insolation

30
Arctic sea ice / Re: The 2018 melting season
« on: June 22, 2018, 09:32:53 AM »
magnamentis, is there any product for measuring cloud cover? I'm loathe to try and eyeball worldview pictures and draw any conclusions.

perhaps a few of the "Pros" know better sources but what i mean, beside the fact that
it applies today as well as each time i was looking in the past 2 weeks, are the ones
linked below.

i hope the link takes you directly to the right page and zoom level

https://www.windy.com/?clouds,66.089,-1.846,3

http://cci-reanalyzer.org/wx/fcst/#gfs.arc-lea.prcp-tcld-topo

as neven said recently somewhere else, it's all about the weather and clouds to my limited understanding are part of that weather.

Clouds are not all equal, some are thick blankets, than exclude the sun, and others thin wisps that maybe more effective in trapping the solarenergy that gets in .  WindyTV shows all sorts of cloud parameters, they are complicated things

The CAB has been obscured by thick cloud, which I think would restrict melt in that region. The Beaufort has also been cloudy over recent weeks, but you can still often see the ice dispersing through it, so I doubt those clouds have been as effective in stopping insolation.  I've included a gif of the 'cloudy' Beaufort over the past 10 days

31
Arctic sea ice / Re: The 2018 melting season
« on: June 21, 2018, 07:53:47 AM »
I made a gif to show how far into the pack the WAM model on WindyTv sees wave action propagating -a long way, 100s of kms -( at least in its 3D version, the 2D maps only show waves waves up to the edge of extent, which is odd.) How real this is I don't know. but if correct in recent days large waves were acting well into the ice north of Svalbard, mixing the surface layer and boosting bottom melt

tech note:

I mangled the colour by forgetting the ice map was indexed when I copied Windy's map over it to attempt to align them so I've included the originals. While both centred on the pole they have different projections so I aligned them on the meridians and the 80N circle
I had a weird battle with the `convert' tool(part of ImageMagick) I use to make gifs and had to reboot to clear some zombie memory cache of rogue frames

32
Arctic sea ice / Re: The 2018 melting season
« on: June 16, 2018, 06:43:54 AM »
There iss a clear view of much of the Svalbard FJI front on worldview onJune 15. I've included a spectacular image of melt south of the Franz Joseph Islands - that's ~ 50k km2 of current extent.

I also used levels to clear thin cloud from part of an image of the edge of the main pack, which has been pushed half a degree south into the melt zone.

The region is now in for a storm with up to 40knot winds blowing first toward Greenland and Fram, and then turning around after a day to blow back the other way. There will be 2.5 metre waves to churn the ice edge as well


33
Arctic sea ice / Re: The 2018 melting season
« on: June 15, 2018, 03:40:53 AM »
Worldview today shows darkening from meltponds and loss of snow across the whole Eurasian side, as well as blue in parts of the CAA

34
Arctic sea ice / Re: The 2018 melting season
« on: June 13, 2018, 05:10:46 AM »
Blue meltponds have appeared on the ESS fast ice over the past couple of days

The silt plume of this lesser river, compared to the Lena(the Pegtymel I believe) entering in the Eastern ESS is visible at least 30km out the sea despite having having only broken a channel through the shore ice. The nutrients in the silt must play a part in algal blooming as well as the immediate effect on albedo, warmth and salinity

2 images from june 13

edit: that silt has been pouring under the coastal ice for a week at least, and the plume can be seen pushed along the coast, with the siltiest area in today's frame only the most recent flow, which must be heading to its peak - I replaced the still with a gif of the last 6 days, The river has been flowing/plume developing longer than that but it was too cloudy to see the water clearly

35
Arctic sea ice / Re: The 2018 melting season
« on: June 12, 2018, 03:12:28 AM »
Nares Strait is also on the move - the last 2 days on Worldview

36
Arctic sea ice / Re: The 2018 melting season
« on: June 10, 2018, 07:05:06 AM »
The ice north of Svalbard has also copped a beating recently.

Its been cloudy, so I monkeyed with the levels of 2 worldview images from June 9 and June 6 to bring out the floes through the clouds. The earlier image shows the smooth melting edge zone that has been sitting just north of 82N for a while. On June 9 we see much of that 50+km wide strip has been reduced to tendrils of melting slush as it was pushed south, increasing extent temporarily, and paradoxically

technical note: in levels(in Gimp, but another editor would be the same) I pulled the black point in to 25, white to 234 and moved the grey point way towards white to 0.32

37
Arctic sea ice / Re: The 2018 melting season
« on: June 10, 2018, 05:32:38 AM »
Wow, the airmass coming in over the Laptev is so warm, the whole region will stay WELL above freezing at 900hPa (around 900m altitude)for the whole forecast period. At the point marked it will remain above 10C into Wednesday, mostly 12 C or more. Later it briefly drops to near zero, but then rerturns to values around 6-8C, though that's too far off to have faith in.

The first few days have to be very bad for ice, what rate of ice thinning do they imply?


38
Arctic sea ice / Re: The 2018 melting season
« on: June 10, 2018, 03:09:53 AM »
The Lena delta to June 9.

With the trend to deeper snow in the far north will the peak flows from rivers like the Lena get even greater, especially if a huge heatwaves comes in early June to melt it all at once, like this year

39
Arctic sea ice / Re: The 2018 melting season
« on: May 24, 2018, 10:12:38 AM »
Wafer Thin refreeze ice north of the Lena delta in the Laptev can't hold out long against current heat influx.. I also made a little gif showing the boundary of the fast ice against a bathymetry map (from the Laptev wiki page) I roughly stretched to match projections

40
Arctic sea ice / Re: The 2018 melting season
« on: May 13, 2018, 04:38:46 AM »
After some wrestling with ffmpeg I've been able to create some movies (rather than gifs) from stills from worldview.

It's been practically cloud free over the Beaufort Sea recently allowing a closer look at the ice, which skows a lot of thin translucent ice between the more solid floes. There's nothing much to inhibit ice movement, and that thin stuff can't last long with constant sun and warm air intrusions.

I've included an animation of a section of the Beaufort Sea( between 71-74 north) from May 6-12, as well as a slightly blown up still from may 11 where the "glue ice" is clearly visible

edit: the first movie wouldn't display, changed the output encoding( to mpeg4 - which again doesn't display - at least in my firefox/ubuntu setup. I'll leave it for now in case others can see it - it plays fine locally)

41
Arctic sea ice / Re: The 2018 melting season
« on: May 13, 2018, 03:18:46 AM »
Extent is tracking 2016 without the the Beaufort (or the Kara) opening up - yet. So that doesn't seem like a good place to be.

Beaufort liftoff has now commenced, and drift projection for next few days posted by Neven indicates it will proceed with gusto

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