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Messages - Clenchie

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1
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 11:33:18 PM »
For those interested in more details on volume, I've just posted PIOMAS July 2019 on the ASIB.

2
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 08:59:49 AM »
Inspired by Ice Shieldz I decided to try and track some some of larger ice floes in the Beaufort starting June 1st. Two floes are marked with a red dot as far as I was able to track them (which was most of the days).

Notice that both floes have large neighbours that disappear. Neither floe moves particularly far in the 36 days, and both floes have basically broken up at the end of the run, one of them not being trackable at all, the other still having a fairly larg piece that I presume could be tracked for a few more days.

3
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 09:20:56 AM »
I guess this is actually part of the ESS rather than the Laptev.
I still have to check the arbitrary boundaries of these seas every so often using NSIDC's MASIE@ https://nsidc.org/data/masie.

Click on browse regions and choose your sea. Example attached.

4
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 11:36:44 AM »
I found a paper called:

Sediment transport by sea ice in the Chukchi and Beaufort Seas: Increasing importance due to changing ice conditions?
...
https://pdfs.semanticscholar.org/40de/e8b9d38feb5d9cfc74ad898d904892a87ac7.pdf

A really great find! Of course, the sedimentary origin of the discoloration has never been in doubt as far as I am concerned until slow wing pointed out that algae growth on the underside can cause the same effect.

But according to the abovementioned paper, the discoloration in the Chukchi is apparently caused in the following manner along the Alaska/Canada shore.

Over shallow waters, preferably 20 - 30 meters but up to 50 meters, turbulence caused by strong winds can lift sediments from the sea floor, at the same time as frazil ice is formed on the surface. Throughout winter, strong offshore winds can create temporary polynia where the process can repeat itself, thus continuing to catch sediments throughout winter.

5
Arctic sea ice / Re: The 2019 melting season
« on: June 24, 2019, 02:59:53 PM »
The landfast ice in the ESS is simply vanishing - the GIF shows ice one day, gone the next. Look closely at the two last frames, large areas of ice simply disappear, but at the same time, the entire field starts shifting to the right and tearing like tissue paper.

Edit: The image is approximately 200km on each side, or 40.000 kilometres squared as the dude likes to say,  even three or four times in each posting, although always with the same spelling mistake.

6
Arctic sea ice / Re: Arctic Image of the Day
« on: June 21, 2019, 05:39:09 PM »
The Freya glacier (Greenland) webcam is online again. Snow cover looks very bad compared to previous years.

https://www.foto-webcam.eu/webcam/freya1/

Really nice webcam images - I like the temp info as well - hits 11.9C on the 16th.  Noticeable that there are lots of blue-sky days as well.

Made an animated gif for the last 30 days:

7
Arctic sea ice / Re: The 2019 melting season
« on: June 16, 2019, 04:32:46 PM »
in all the years that I've been watching the ice in the Arctic, the CAA has always seemed to me to be totally "out of it", i.e. not really part of the Arcic Sea Ice proper. It doesn't really move, it doesn't take part in any exciting developments, it sometimes melts enough to allow cruise ships to sail through - but to give it any major linchpin significance in crash-predictions seems to me to be totally spurious.
I agree.

I made a set of graphs looking at how the various seas are transforming from icy deserts to open water seas. The CAA is one of a few seas where one would think that global warming has passed it by.


8
Arctic sea ice / Re: The 2019 melting season
« on: June 16, 2019, 04:27:27 PM »
I too think the attention to the CAA is overblown.

If I'm looking at one key area right now, it's the ESS. You've got a big head start on either side of it with a lot of open water in the Beaufort and Laptev.

If the ESS takes off and the inner seas form a continuous body of water, then the Central Arctic is open to the most avenues of attack.


9
Arctic sea ice / Re: The 2019 melting season
« on: June 16, 2019, 04:05:00 PM »
" I don't see why there couldn't be a crash in arctic ice without there being a crash in CAA ice - the reasoning eludes me."
My take is that with the CAA open the least saline, easiest to freeze fraction can flow through to Baffin forced by every tidal cycle, high pressure system etc. so in some way, blocked, it acts as a pressure regulator on the entry of Pacific/Atlantic waters. So the ice could crash but probably not a new record.

I still don't see the logic. In 2012 the CAA was not significantly different from most other years (a difference of 100.000 to 200.000 km2) and in all the years that I've been watching the ice in the Arctic, the CAA has always seemed to me to be totally "out of it", i.e. not really part of the Arcic Sea Ice proper. It doesn't really move, it doesn't take part in any exciting developments, it sometimes melts enough to allow cruise ships to sail through - but to give it any major linchpin significance in crash-predictions seems to me to be totally spurious.

10
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 15, 2019, 02:44:23 PM »
Since 2002, NSIDC Arctic Sea ice extent has never seen three consecutive days of increase in June. And most of the previous times there's been even a single day of alleged growth in June, that day (or those days) have been sandwiched between, or immediately adjacent to, very large decreases.

For example. 2014 saw two consecutive days of growth, but those were immediately preceded by a drop of 210k, and immediately followed by a two-day decrease of 278k. 2007 had a drop of 124k sandwiched between increases of 69k and 13k. 2002 had a drop of 120k, then a rise of 8k, then a drop of 109k. And even big bad 2012 had a rise of 5k--followed by a 10-day ice feast that saw the loss of 1.3M.

My prediction, then, based on observation, climatology, and history: 2019 is about to see a very large--perhaps even record-breaking--drop in ASI extent.

Because This here? It ain't normal. And that means something:


11
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 14, 2019, 11:11:12 AM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. Jun 04 - Jun 13
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php


12
Arctic sea ice / Re: Arctic Image of the Day
« on: June 13, 2019, 03:20:57 PM »
Another flipped iceberg.


13
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 11, 2019, 11:23:17 PM »
Further to the Kane Basin fast ice disintegrating, there are several grounded icebergs

Thanks for the reminder, Tor - had almost forgotten about that bit of research I did! Have been following this thread with interest this year.

14
Arctic sea ice / Re: The 2019 melting season
« on: June 11, 2019, 10:03:49 PM »

If anyone has more info on the situation I'd be happy to read it.

I think this article from Climate Policy gives a nice overview: 

Quote
Cold Halocline

Fri, 27 May 2016 | Canadian Arctic

The cold halocline is a water layer within the Arctic Ocean that lies below the very fresh surface waters and above the saltier Atlantic layer. Where it is well developed, its low temperature serves to insulate the overlying sea ice from the heat residing in the Atlantic layer.

. . .

Just above the halocline lies the ocean surface layer, which is constrained to be at or very close to the freezing point where it is in contact with sea ice. This 10-60 m thick layer is not very dense, mostly because of discharge from large rivers in Siberia and North America.

. . .

Below the surface layer, salinity increases downward but the temperature stays near the freezing point. This is the cold halocline.

. . .

Below the halocline, at depths of 150-800 m, lies the warm and salty Atlantic layer. This layer fills the entire Arctic Ocean, from its origins in the Norwegian Sea to its exit through Fram Strait into the Greenland Sea. Its salinity is typically 34.8-35.0, and its temperature varies from about 3°C north of Svalbard to less than 0°C north of Canada. Since the freezing point of this water is about -1.8°C, even the coolest Atlantic layer water is a few degrees above freezing. Although this seems small, it represents enough heat to completely melt away the overlying sea ice pack if it were somehow able to mix up into the surface layer.

The most vigorous source of mixing in the Arctic Ocean is generally from surface processes such as winds, sea ice motion, and the sinking of heavy waters formed by air cooling or sea ice growth. In the absence of a cold halocline, such processes might easily mix the Atlantic layer heat up into the surface layer and thus bring this heat into contact with the sea ice pack. This generally does not happen, however, because the halocline represents a stable barrier to surface mixing, that is, it is hard to penetrate this gradient in density. Even if the surface mixing were vigorous enough to penetrate into the halocline, it would only entrain water that is quite cool, and thus have little thermal effect on the sea ice pack. This inhibition of upward heat flux from the warm Atlantic layer is the main physical consequence of the cold halocline.

Recent studies have shown that Arctic wind and surface air temperature patterns vary substantially on a multiyear time scale. These climate oscillations have affected the cold halocline by influencing where fresh surface waters circulate. In the late 1980s and early 1990s, an unusual wind pattern persisted that diverted river water away from the surface layer of the Amundsen Basin. This led to a retreat of the cold halo-cline from this area, leaving the surface layers directly exposed to the underlying warm Atlantic layer. This presumably is suppressed by the growth of wintertime sea ice in this area, but not for too long: the halocline began to rebuild as wind patterns shifted in the mid-1990s. If such climate oscillations persist or amplify in the future, then the Atlantic layer heat may play an increasing role in the ocean surface energy balance, that is, in keeping the sea ice pack thinner than it is now. This is the present situation in the Antarctic Ocean, which lacks a cold halocline and thus has a thinner sea ice pack that largely melts away every summer.

https://www.climate-policy-watcher.org/canadian-arctic/cold-halocline.html


 

15
Arctic sea ice / Re: The 2019 melting season
« on: June 11, 2019, 03:12:08 PM »
Mercator (model) sea surface temperature (0m) may1-jun10, pacific side.

16
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 10, 2019, 06:29:38 AM »
BOOM!

17
Arctic sea ice / Re: The 2019 melting season
« on: June 06, 2019, 07:00:59 PM »
Take a look at 6Z GFS.



THIS IS JUST UNBELIEVABLE HEMISPHERIC WIDE. 

POWERHOUSE DIPOLE ANOMALY THIS WOULD GENERATE ENORMOUS AMOUNTS OF HEAT IN THE NORTHERN LATITUDES.

I'M JUST ASTONISHED WE HAVEN'T SEEN SOMETHING LIKE THIS IN JUNE SINCE WHEN IT COME ON SOMEBODY SHOW ME.

Greetings from 65,5N in Scandinavia. It's freakishly hot today, we have +23C cloudless at 19:00. Which would be an insanely warm night in July, normally.

Buckle up. Summer is here.

18
Arctic sea ice / Re: The 2019 melting season
« on: May 22, 2019, 09:21:48 AM »
I've been browsing worldview and here's the thing that strikes me thinking about the six odd years that I have been watching the ice on this forum; no one region (well maybe the Bering) is especially bad or "worst" that we have seen.  It is hard to quantify, but what stands out is no region is in "good" shape.  Metrics across the arctic for area, thickness and extent all seem to be in the bottom three worst of our record, with few exceptions. Visually, anecdotally across the basin the ice quality looks awful, and I'm waiting to watch melt ponds break across the basin like a nasty rash.

The metaphor I come back to is a punch-drunk boxer swaying helplessly after climbing up off the mat.

Instead of looking for 2+ sigma events that could mangle the ice, we are hoping for 2+ sigma events to prevent a repeat of 2012.  That, by itself is quite a change. One good shot, and it's over, but worse, it no longer needs to be a haymaker to put us into 2012 territory.

19
Arctic sea ice / Re: Arctic Image of the Day
« on: May 10, 2019, 06:13:11 PM »
Huge iceberg floe bumping into Hans Island in Nares Strait beautifully captured by Sentinel.

Edit: Thanks Uniquorn for the correction.

20
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: April 13, 2019, 03:15:36 PM »
The recovery in sea ice area in the Chukchi, Kara and Laptev Seas is quite impressive.
For consistent gradual sea ice area loss one goes to Baffin Bay.

21
Arctic sea ice / Re: The 2019 melting season
« on: April 07, 2019, 02:27:37 PM »
CAA end of the Beaufort stringer nudges back to a more normal southerly position opening up multiple fractures further north.
Thickest ice next to CAA briefly lifts off opening a temporary fracture northwards.
Nares still open. Fram export strong.
CAB to Barentsz export fairly neutral.
Kara mostly exporting to Barentsz rather than CAB.
Old Laptev ice drifts westwards past SZ.
Old CAB ice edge drifts ever nearer to the pole.
ESS tendril stretched further.
Chukchi battles with the Pacific

ascat day57-96(heavy contrast)


22
Arctic sea ice / Re: The 2019 melting season
« on: April 03, 2019, 03:59:24 AM »
The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.

Processes controlling surface, bottom and lateral melt of Arctic sea ice in a state of the art sea ice model

https://www.researchgate.net/publication/281622252_Processes_controlling_surface_bottom_and_lateral_melt_of_Arctic_sea_ice_in_a_state_of_the_art_sea_ice_model

Relevant graph from the article attached.


23
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 07, 2018, 12:30:38 AM »
Agreed, patches of flash freezing already visible.... but the pack is so mobile, looking a bit wounded almost (obviously I'm reading too much into it ;) )
ascat, last 20days (enhanced contrast,clahe,unsharpmask)

24
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 30, 2018, 06:25:38 PM »
Thick ice dragged back out of the Mclure Strait.
Worldview, viirs brightness temperature, band15, night, nov21-30. (1.1MB)

25
Arctic sea ice / Re: The 2018 melting season
« on: August 15, 2018, 12:12:40 PM »
I've tried a different exercise with the Lincoln sea ice.

I chose a floe visible in a Sentinel image, and followed it backwards (and forwards - this took a little time to prepare) in time. The animation below shows images rotated and matched.

The floe is currently about 20km north of the fast ice breaking out of the bay to the south of the Lincoln Sea.

The images were captured at the 300m scale and the floe is about 2km x 2km.

It seems that it suffered a lot of fracturing early on, but more recently has held its shape very consistently.

26
Arctic sea ice / Re: The 2018 melting season
« on: August 15, 2018, 08:35:24 AM »
Continuing on the Lincoln Sea theme, and following Neven's question about the fast ice breaking in other years, I prepared this animation showing a selected clear mid-Aug day for each of the years 2001-2018. The only year that looks similar to this year's state of the ice is 2015, though I don't know if the wind played a larger factor that year. The fast ice OTOH does break on many of the years.
It is very educational to witness the huge size of the floes in many of the years.

27
Arctic sea ice / Re: The 2018 melting season
« on: August 01, 2018, 07:17:25 PM »
since the ice north of greenland is not stationary but imported mostly it's ore or less arbitrary, exactly like where exactly each year we have thicker or thinner ice.

it depends on currents and prevailing winds a lot where the ice is driven and when during the year so that one year a specific type of ice is accumulated in one region and in another the next season.


28
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: July 16, 2018, 04:54:35 PM »
The wind has been blowing the Kane Basin ice 'up stream' (northeastward) and the Smith Sound ice northward for the past week or so.  GIF prepared from DMI Sentinel images from July 9, 11 and 14 (dates are on gif). Two floes are roughly outlined to make it easier for you to following the motion.

According to Windy.com, forecast winds are mixed north and south (back and forth) this next week.

29
Arctic sea ice / Re: The 2018 melting season
« on: July 04, 2018, 12:23:34 PM »
https://wxclimonews.com/2018/07/02/extreme-heat-event-in-northern-siberia-and-the-coastal-arctic-ocean-this-week/

Figured I would just post the link, rather than try to transfer all the great stuff in this article.

30
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 29, 2018, 11:55:21 PM »
The Lincoln sea ice is already funnelling into the gap left further up the channel. With the collapse of the arch this should continue.

Click to animate.

31
Arctic sea ice / Re: The 2018 melting season
« on: June 16, 2018, 08:31:15 AM »
Watch that fast ice crumble! This is three days' worth of imagery of the Laptev Sea, 14, 15 and 16th June.

(Click image to see animation).

32
Arctic sea ice / Re: The 2018 melting season
« on: June 10, 2018, 02:10:55 PM »
So, one possible interpretation of these data is that the pulse of summer heat flow is coming down the Lena river, but it has not fully hit the Laptev Sea yet.  That would in turn explain why there has been so little melting yet of ice at the edge of the delta where it meets the sea ice.
Firstly, Lena brings to Laptev large amount of river ice and cold fresh water. Ice flow finished couple of days ago. Before this moment, incoming water has no chance to warm significantly.

33
Arctic sea ice / Re: The 2018 melting season
« on: June 05, 2018, 04:11:57 PM »
Nullschool shows possible unfolding of events in terms of all that fragmented ice in the northern/eastern Kara Sea.   It shows two days (including today) of strong, warm winds blowing ice floes in northern/eastern Kara Sea towards and perhaps into the ice-free Barents.  Followed by two days or more of powerful winds swirling those floes vigorously around.  Waves will get a head start since there is quite a lot of open water in the ice openings parallel to the Russian coast in the extreme eastern portions of the Kara. 

Wind speed readings are for the area just to the right (or south) of Franz Josef Land (green circle dot just visible).  I chose this because it is near the current ice 'edge'.

34
Arctic sea ice / Re: The 2018 melting season
« on: May 25, 2018, 06:52:05 PM »
Thank you FishOutofWater.

A couple of days of above zero temperatures are forecast for some of the Kara Sea. Clearer weather today allows a look at that area with worldview viirs brightness temperature band 15.

images are enhanced a little using imagej unsharp mask 1,0.6

Ice looks fairly healthy there and it is a little slow out of the gate.

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