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Messages - uniquorn

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1
Arctic sea ice / Re: Tides
« on: Today at 09:24:30 AM »
In my humble opinion, mosaic buoys are showing tidal movement that affects melt. They have been showing it ever since the project started. Tidal movement is less detectable further north. Some people see it, some don't, and some don't want to see it.
The ICEX buoys may show it too when I zoom in on them later.

2
Arctic sea ice / Re: Tides
« on: August 03, 2020, 01:57:49 PM »
<>The tides are always there doing their bits with eddies and some fast ice breakup (e.g. in the CAA) but the ice north of Greenland does not melt and retreat north every summer.
I expect that shelf break melt will become a more accepted part of the melting season as the arctic moves to a higher percentage FYI. Without a constant supply of MYI, north of Greenland could start to look more like north of FJL/Svalbard, dependent on wind direction.
Unfortunately there is only a buoy swarm in the Fram at the moment. Most viewers will be able to detect non negligible tidal movement. For me this disproves the theory that tides just go up and down with a negligible tidal current that has no effect on ice. There is, to me, clearly a more circular motion involved, suggesting eddies and mixing that would affect ice melt, particularly at shelf breaks, where the underlying slope of the ocean floor likely amplifies the turbulence.
These buoys are over 250km from nearest land

shelf break image from http://mseas.mit.edu/Research/MOPE/index.html  (not arctic but shows some of the processes)

added gif from http://rob-hetland.blogspot.com/2005/04/shelf-break-front-simulation.html
Quote
Shelf break front simulation
Here is a sample cross-section from an idealized shelf break front simulation. The contours are salinity, the colorfill velocity.
This is exactly the kind of movement seen in the FJL/Svalbard gap.  click
rammb example here

3
Arctic sea ice / Re: The 2020 melting season
« on: August 03, 2020, 12:23:45 PM »
update on melt north of greenland using amsr2-uhh, jul26-aug2
chaotic mix of wind, currents and tides in the Fram Strait/Greenland Sea shown by mosaic buoy drift, jul20-aug3

4
Arctic sea ice / Re: The 2020 melting season
« on: August 03, 2020, 01:35:53 AM »
amsr2-uhh for 2012 is available from aug1. I tried hard to replicate this comparison of 2020 with 2012 but A-Team's is better. Passing it on unmodified.
Green is open water for both years
Orange, open water in 2020
Pink, open water in 2012.
pixel count overlayed onto greenland
click to run

5
Arctic sea ice / Re: The 2020 melting season
« on: August 03, 2020, 12:37:38 AM »
overlay of amsr2-uhh on to mercator(model) 0m ocean temperature. jul1-aug1. (9.5MB)

6
Arctic sea ice / Re: The 2020 melting season
« on: August 02, 2020, 01:48:05 PM »
These thickness graphs, while useful, never have materialized in a complete meltout.
They might be more representative of the ice state than a one day difference image.

Here looking at the CAB 'decompacting' north of Laptev. Identifiable features drifting south while the ice edge stays relatively static.

7
Arctic sea ice / Re: The 2020 melting season
« on: August 02, 2020, 11:44:57 AM »
Animation of the development of low concentration ice and open water north of Greenland. amsr2-uhh, jul27-aug1

8
Arctic sea ice / Re: The 2020 melting season
« on: August 01, 2020, 08:20:32 PM »
polarview S1 of the after effects of the brief low in the chukchi/beaufort, jul31

9
Arctic sea ice / Re: What the Buoys are telling
« on: August 01, 2020, 05:26:56 PM »
JAMSTEC/ICEX buoys currently in the Chukchi
Quote
About Warm Buoy & SideKick

JAMSTEC WARM (Warming and Irradiance Measurements) Buoy project has started to comprehend temporal changings of oceanic enviornment from ice-covered season toward open-water season. Thr WARM Buoy and Side Kick system (see below) was deployed at ICEX 2020 camp station in Beaufort Sea. These systems measure vertical structure of water mass (temperature and salinity) and chlorophyll-a fluorensence from surface to 60-m depth for every 1-hour and send via iridium satellite communication system (see real-time data page). SideKick monitors daily time series of upper-ice views (see gallery pages).
We kindly acknowledge US Navy Arctic Submarine Laboratory and Pacific Gyre Inc. for their kind support for this project. For your information, please also see UpTemp0 web site by University of Washington and WARM Buoy project of Old Dominion University.

Sidekick takes pictures :)
clear images from may1-jul26  click

10
Arctic sea ice / Re: The 2020 melting season
« on: August 01, 2020, 03:15:25 PM »
Overview of buoy drift in the Beaufort/Chukchi, then zooming in on that cluster of JAMSTEC/ICEX buoys currently in the Chukchi
Quote
About Warm Buoy & SideKick

JAMSTEC WARM (Warming and Irradiance Measurements) Buoy project has started to comprehend temporal changings of oceanic enviornment from ice-covered season toward open-water season. Thr WARM Buoy and Side Kick system (see below) was deployed at ICEX 2020 camp station in Beaufort Sea. These systems measure vertical structure of water mass (temperature and salinity) and chlorophyll-a fluorensence from surface to 60-m depth for every 1-hour and send via iridium satellite communication system (see real-time data page). SideKick monitors daily time series of upper-ice views (see gallery pages).
We kindly acknowledge US Navy Arctic Submarine Laboratory and Pacific Gyre Inc. for their kind support for this project. For your information, please also see UpTemp0 web site by University of Washington and WARM Buoy project of Old Dominion University.

Sidekick takes pictures :)

11
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 30, 2020, 03:18:04 PM »
Too salty? - Don't know. I find it difficult to interpret 0m salinity under ice and after seeing the Tbuoy data I'm not sure that much should be inferred from modelled data. That said, itp114 looks interesting recently, though data starts at 7m depth. Will check it out later.
image removed

12
Arctic sea ice / Re: The 2020 melting season
« on: July 30, 2020, 11:57:59 AM »
superimpose (and synchronize) the cyclone and the concentration images
I think amsr2 is representing the state of the ice quite accurately in this case.
click

13
Arctic sea ice / Re: The 2020 melting season
« on: July 30, 2020, 11:18:46 AM »
A quick view, after the worst part of the storm...
uni-hamburg version, amsr2-uhh, beaufort-chukchi, jul18-29 
click

14
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 29, 2020, 11:01:26 PM »
beaufort/chukchi low for reference

15
Arctic sea ice / Re: What the Buoys are telling
« on: July 29, 2020, 10:27:07 PM »
Kept the drift speed in and added BP as label. At least one buoy has a faulty barometer but it has been left in to remind that representations of raw data need to be treated with caution.
It's possible that drift speed went higher during the gaps in the drift path.

16
Arctic sea ice / Re: What the Buoys are telling
« on: July 29, 2020, 09:25:12 PM »
Some have BP.

Quote
ITP117 was deployed on a 1.35 m ice floe in the Beaufort Sea on September 19, 2019 at 80° 55.0 N, 135° 31.9 W as part of the Beaufort Gyre Observing System (BGOS) during the JOIS 2019 cruise on the CCGS Louis S. St. Laurent. On the same icefloe, a prototype Tethered Ocean Profiler (TOP), and a US Army Cold Regions Research and Engineering Laboratory (CRREL) Seasonal Ice Mass Balance Buoy 3 was also installed. The ITP is operating on a standard sampling schedule of 2 one-way profiles between 7 and 760 m depth each day and includes a fixed SAMI PCO2 with ODO and PAR at 6 m depth.
This looks like the cryosphere simb sharing a floe with itp117

17
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 28, 2020, 08:50:52 PM »
mercator salinity, 34m, mar21-jul27
best viewed at half speed

18
Arctic sea ice / Re: The 2020 melting season
« on: July 26, 2020, 11:30:22 PM »
amsr2-uhh, atlantic side, jul1-25

19
Arctic sea ice / Re: What the Buoys are telling
« on: July 26, 2020, 09:51:42 PM »
Added a few more buoys to the drift animation. Someone is collecting a large swath of data in the Beaufort/Chukchi

20
Arctic sea ice / Re: MOSAiC news
« on: July 26, 2020, 02:38:00 PM »
Added couple of drifter buoys in the Greenland sea (not on ice) for a wider perspective

21
Arctic sea ice / Re: The 2020 melting season
« on: July 25, 2020, 10:21:09 PM »
What is the likelihood that the entire ice sheet will unfasten from the CAA and Greenland?
Quite likely for a few days.

Drift update from a few more iabp buoys, including one in the ESS and a few more mosaic buoys on the atlantic side. Also one that's apparently being deployed in the west spitsbergen current.
click 10MB

The second animation is shorter with 10s delay in case anyone needs the numbers.
The titles are incorrect. These are not all whoi buoys, just iabp
edit: lol bbr. How will it hit an iceberg if they all melted?   ;)

22
Arctic sea ice / Re: The 2020 melting season
« on: July 25, 2020, 06:04:20 PM »
I believe this more of a coincidence than meets the eye. In normal years the deep Beaufort is much emptier of ice, the shallower ESS often has lots of ice at this stage. And this year the deep Laptev/CAB sector is ice-free.
amsr2-uhh overlaid onto gmrt bathymetry, minimum jaxa dates, 2012-2018
must add 2019 sometime.
edit:Perhaps someone will put together all the nsidc minimums one day. I think they go back a lot further. If they do, I will attempt to overlay them onto bathy.

23
Arctic sea ice / Re: MOSAiC news
« on: July 25, 2020, 12:02:11 PM »
Drift update as the buoy 'peleton' approaches the larger eddy. An overview from Kaleschke sic leads, which shows the eddies very well, updated with 2 days of amsr2-uhh, jun26-jul24.

 A closer look using Pbuoy drift jul15-25 (click, 4.6MB)

24
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 25, 2020, 11:31:43 AM »
Nice, though I'm not sure what band I4 is showing. Mercator temperature resolution is too low to show much change on the Ellesmere coast yet. Salinity is often a better indicator of up/downwelling. Here is the modelled 0m salinity jul1-24 and 0m temperature, jul18-24

It could just be insolation, probably both.

25
Arctic sea ice / Re: MOSAiC news
« on: July 23, 2020, 07:03:44 PM »
Jul16-22 mosaic multisensor map (forgot to include dates), click to run
I slowed the animation down a bit and improved the contrast near the PS location on 3 of the images. PS just skirts the open water of the eddy. The bright dot is easily visible.
click twice for full res.

26
Arctic sea ice / Re: MOSAiC news
« on: July 23, 2020, 12:56:32 PM »
Thanks seaice.de.



Temporary post of conversion to mp4

27
Arctic sea ice / Re: The 2020 melting season
« on: July 23, 2020, 10:28:07 AM »
Beaufort thinning out already. Big block in the middle 'pulverised'
amsr2-uhh, jul12-22 click

28
Arctic sea ice / Re: The caa-greenland mega crack
« on: July 23, 2020, 12:11:45 AM »
Clear day, big picture. https://go.nasa.gov/2ZRSZaB

29
Arctic sea ice / Re: The 2020 melting season
« on: July 22, 2020, 11:28:03 PM »
Note that worldview shows cracks up and down the main channel and ice may be beginning to flow through the Davis strait. It certainly is cracking up and moving at the south end towards Baffin bay.
The dominoes are beginning to fall on the north American side of the Arctic.
Yes. Looking weak all the way to the Mclure Strait. Heavy linear contrast to show fractures.

30
Developers Corner / Re: Test space
« on: July 22, 2020, 10:06:23 PM »
interesting mosaic ani. no coordinates ...

31
Developers Corner / Re: Dev library
« on: July 22, 2020, 05:47:35 PM »
A-team method in gimp for extrapolating possible melt using hycom thickness
Quote
mark up low values on palette better with grid tool on a transparent layer
vary radius until it picks up 0.5, 0.55, 0.6, 0.65, … 1.0
invert selection
make new layers and fill with neutral color, each time saving painted palette too
make slow animation being sure to start with unaltered. frames are nested by construction.

32
Arctic sea ice / Re: The 2020 melting season
« on: July 22, 2020, 03:13:45 PM »
amsr2-uhh, Beaufort, jul20-21 and difference
click to run
JayW rammb here

33
Arctic sea ice / Re: The 2020 melting season
« on: July 22, 2020, 02:55:11 PM »
I doubt this resolves the compaction debate but here is what osisaf(mid date) overlaid on nullschool 1000hPa wind (0900hr) looks like. jul1-17
Complex  (click to run, 2.6MB)

34
Arctic sea ice / Re: MOSAiC news
« on: July 22, 2020, 11:10:15 AM »
Mosaic Pbuoys passing through the 'Fram flux gate', jun25-jul22

35
Developers Corner / Re: Test space
« on: July 21, 2020, 02:17:22 PM »
ibcao v4
glasbey LUT on ESS to highlight shallow contours

36
Arctic sea ice / Re: The 2020 melting season
« on: July 20, 2020, 09:44:01 PM »
A casual look through the iabp table is a bit like playing 'find objects'
Anyway, we have some new (and old) buoys. Will have to resolve a drift speed problem but here is the first draft. click to run
I suppose some area calcs might resolve the compaction issue but I'm not going there

37
Arctic sea ice / Re: MOSAiC news
« on: July 20, 2020, 11:25:29 AM »
Old news but quite interesting.

https://blogs.agu.org/thefield/2020/07/17/postcards-from-a-frozen-icebreaker-part-35/
Quote
By Matthew Shupe

6/19/20 Taking things head on
We ran into the floe. Directly. While scientifically we decided it would be best to moor to the floe along the ship’s port side to facilitate CTD operations, others onboard have been concerned about the Polarstern’s ability to hold its position alongside the floe in the face of ice pressure. We’ve, of course, experienced a lot of pressure thus far, which has been a great challenge at times. And so, the decision was made to instead drive straight into the floe and attempt to embed Polarstern. This type of position, the thinking goes, would allow the ship to be effectively protected from some of the ice forces by the floe itself. Polarstern cruised out from our parking spot from the last days and navigated around the floe to the south and then east, then cruised full speed ahead directly into the SE flank of the remaining MOSAiC floe. The ship was eventually stopped by the very thick ice, ridged and chunky. Backed up for another go, trying to embed further, but no such luck. The floe was not allowing such an entrance, and instead a crack opened up to the port side and another chunk of the floe broke off. Ever smaller the floe gets. In the morning the captain maneuvered the ship so that the starboard side was along the ice floe, and we will stick in this position and see how things go.

38
Arctic sea ice / Re: The 2020 melting season
« on: July 19, 2020, 04:12:11 PM »
update on buoy drift, april-jul19
left a long name mosaic buoy in by mistake
Mosaic travelled a fair way west before heading south again recently

39
The forum / Re: Forum Decorum
« on: July 19, 2020, 02:45:32 PM »
For such a busy thread, I think Oren is doing a great job. I doubt that any one of us could do better.

40
Arctic sea ice / Re: The 2020 melting season
« on: July 18, 2020, 10:42:08 PM »
Agreed. CAB compaction. A lot of talk but no analysis yet. Here looking at four identifiable points from jul10-17 north of Laptev.  https://go.nasa.gov/3fGWDd7
area jul10=64,120.16km^2
area jul18=63,738.14
ratio= 0.9903. Compaction in this area=not much
   a       nice      slow      animation 
The tools are all on worldview. An enthusiast might measure a larger area

41
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 18, 2020, 08:52:10 PM »
If the explanation is obvious, why no lift off from pgas? And no bounce, which probably wasn't obvious. edit: maybe ossifrage has an explanation.

Posting a rough amsr2 overlaid onto mercator (model) 34m salinity while I attempt to work through some suggested presentation improvements. jun1-jul17
scales are probably meaningless with the overlay. red salinity>yellow>green>blue

Laptev modelled diluting or mixing the salty atlantic finger.

42
Arctic sea ice / Re: The 2020 melting season
« on: July 18, 2020, 04:18:12 PM »
mercator 0m (ocean) temperature with amsr2uhh overlaid at 80% transparency. amsr2 0% concentration has been set to fully transparent. jun1-jul17

43
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 17, 2020, 05:30:27 PM »
Not really bouncing. Two points of interest here, the large lift off and the smaller floe (marked) drifting in a different direction

added large rammb, jul13-17

44
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 17, 2020, 01:26:51 PM »
I think this area might tell us something

45
Developers Corner / Re: Test space
« on: July 16, 2020, 11:43:50 PM »
testing 15 days of ice edge, mine is only half size but file is 4 times bigger--

46
Arctic sea ice / Re: MOSAiC news
« on: July 16, 2020, 09:50:51 PM »
Delaunay triangulation of a selection of buoys using iabp data to see what they show of the incident on jul12 (day194)

47
Arctic sea ice / Re: The 2020 melting season
« on: July 16, 2020, 04:09:57 PM »
Laptev melt highlighting one of Friv's large floes.
https://go.nasa.gov/3eAlCx9 (cropped), jun8-jul15  9.8MB

48
Arctic sea ice / Re: The 2020 melting season
« on: July 15, 2020, 10:28:56 PM »
Update on 6 whoi itp buoys in the Beaufort. The charts show data from 6m depth, so some way below most of the ice. Temperature is rising on all of them. Some more than others.

49
Arctic sea ice / Re: The 2020 melting season
« on: July 15, 2020, 09:06:47 PM »
A very unusual image:
https://GreatWhiteCon.info/2020/07/facts-about-the-arctic-in-july-2020/#Jul-15
Thanks Jim. Here is a contrast adjusted version of https://go.nasa.gov/2OpqJFS to bring out more melt pond detail. There is some light cloud in places on this image (edit:which is a day later.)
Click for full res and unaltered image

Added the histogram for the original image, mean intensity(unweighted) = ~205/255, 80% as a first approximation for visual freq range albedo. ;) obviously should have taken the graticule out for that..

50
Developers Corner / Re: Test space
« on: July 15, 2020, 08:30:20 PM »
testing large caa, freeze-melt--

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