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Messages - uniquorn

Pages: [1] 2 3 ... 15
1
Arctic sea ice / Re: The 2019 melting season
« on: Today at 12:44:48 AM »
<snippage>
Stronger than normal NW winds in the Labrador sea this late winter is a continuation of a pattern we saw late last winter and spring when there was a strong atmospheric vortex around Greenland. This pattern causes larger than normal amounts of fresh water flow out of the CAA into the Labrador sea.
hmmm. It must be significantly larger than normal to let thin ice travel 200km further south.

Or perhaps just a one off fluke?

2
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: March 18, 2019, 11:29:48 PM »
So the Nares is mostly flushed of old ice.
I enjoyed Tor's poll. It encouraged me to actually read the scientific papers on the Nares that he and others suggested and it made me look (eventually) at terramodis brightness temp back to 2000. Useful for longer time comparisons despite the lower resolution than suomi/npp. https://go.nasa.gov/2Jn5YuX
If it showed one thing it was that Nares watchers are reluctant to vote.  ;)
My vote was incorrect and the arch has held for longer than 'soon' now.

3
Arctic sea ice / Re: The 2019 melting season
« on: March 18, 2019, 02:20:56 PM »
Antivirus didn't like the certificate.
Interesting. I don't look that far south very often.
edit:For those with limited 2d spatial recognition, myself included, here is hycom gulfstream sst 2015-2019 mar17(or closest date). Will compare with mercator later.

4
Arctic sea ice / Re: The 2019 melting season
« on: March 18, 2019, 01:46:16 PM »
I didn't want to be alarmist and mention the Beaufort Gyre  ;)

bbr your image links are broken for me.

5
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: March 18, 2019, 12:59:47 PM »
Seemed like a good day to go historical. Here is worldview Terra/Modis, least cloudy days between mar16-20, 2000-2019.

6
Arctic sea ice / Re: The 2019 melting season
« on: March 18, 2019, 12:43:00 PM »
Thank you both. Agreed, the tendrils are further south, maybe 200km. SST must be cooler or surface salinity fresher there. Perhaps as a result of all the MYI in the CAA last season?
edit: Concentration is a lot lower this year though.

7
Arctic sea ice / Re: The 2019 melting season
« on: March 17, 2019, 10:24:15 PM »
The ice front off Newfoundland has made remarkable progress south. It is hardly consistent but I believe these tendrils may be the furthest south in the satellite record by a wide margin.
Pretty close to 2014 and 2015 on amsr2 so far. I'll let you confirm with worldview(geographic maybe?)  :)
amsr2, newfoundland, mar2013-2019

8
Arctic sea ice / Re: The 2019 melting season
« on: March 17, 2019, 06:17:03 PM »
DMI (sep24-mar15) and PIOMAS (sep24-feb28) thickness models for last freezing season for reference.
Both models suggesting that the area north of FJL/Svalbard is weak for some distance. It does look a bit 'crazy paving' in viirs, brightness temperature(band15)night  https://go.nasa.gov/2JlnwY8

added cryosat 28day, feb13-mar13 for comparison.

9
Arctic sea ice / Re: The 2019 melting season
« on: March 17, 2019, 12:51:33 PM »
http://polarportal.dk/en/sea-ice-and-icebergs/  ice surface temperature for the last freezing season (for reference)

10
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 16, 2019, 03:18:49 PM »
A good view of our thickest ice today on worldview. https://go.nasa.gov/2Jiqwom
The animation shows viirsbt15n default, enhanced contrast and then enhanced local contrast. (3.5MB) click on the image to run


11
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 16, 2019, 01:37:14 PM »
Some cloud today but (mostly) new ice is flowing along the western edge down to the remnants. There might be a bit of a logjam near there but it's tricky to see on worldview.
I'm happy for slowpoke to be an interested bystander in all this. D-Day slipped its shackles, newbie changed its mind and edged back.
Worldview-viirsbt15n, mar15-16   https://go.nasa.gov/2Hp99Aw

12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 16, 2019, 10:45:11 AM »
Short lived optimism fades as the pack shears effortlessly on it's way.
Worldview, viirsbt15n, atlantic front, mar15-16 https://go.nasa.gov/2JgBFpF
cryosat, feb13-mar12 (without smos) inset 
http://www.cpom.ucl.ac.uk/csopr/seaice.html?big_thickness_image=1&thk_period=28&season=Autumn&year=2018

13
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 15, 2019, 11:20:40 PM »
A plug for https://cryospherecomputing.tk

Regional cumulative albedo-warming values (anomaly) 1979-2018


14
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 15, 2019, 10:30:04 PM »
I had hoped that showing the data in a different format would clarify what is happening between 300-800m but I can only see that some event occurs and the sensors get stuck on the line. Possibly turbulence but no measurements.

This looks interesting though data is only up to 2015 and it concentrates on 0-150m.
Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean.
http://science.sciencemag.org/content/356/6335/285.full
DOI: 10.1126/science.aai8204
Quote
The deep winter ventilation and the disappearance of the CHL in the eastern EB (eastward from Severnaya Zemlya, >90°E) at several mooring sites in 2013 to 2015, however, are unprecedented (Figs. 3A and 4). Substantial changes in seasonal heat content Q (see definition in the supplementary materials), driven by surface cooling and salinification during winter sea-ice formation, occurred in the upper 130-m layer at M3e, M13, M16, and M6b mooring sites. If this trend persists, convectively driven winter development of the deep (>80 m) SML, combined with ventilation of the upper 130-m ocean and associated disappearance of the CHL would represent a fundamental change, with the eastern EB water-column structure becoming less stratified and susceptible to further mixing.

I'll find out what a wavelet transform is and see if that helps....

15
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 15, 2019, 08:22:45 PM »
Mercator 0m salinity, jan1-mar14, used here to show current and possible upwelling along the Alaskan coast from Chukchi to Beaufort.
Worldview viirsbt15n, mar10-14 confirming.
FOOW warm water coming back up to haunt us perhaps

edit: forgot salinity scale

16
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 15, 2019, 07:34:47 PM »
On the more optimistic side, large floes are finally compacting into NE Svalbard. They have a few days before the wind changes to make an attempt at fast ice. <snippage>
Not so optimistic imo. This is a lot of ice parking in Death Row, whether it is weeks or months the Atlantic currents will say.
Agreed, all the ice there will melt next season, but some fast ice would encourage a small resistance, for a while, to the recent relentless surge towards the Atlantic. It is disappointing that the older ice further east hasn't connected with SZ. Weak ice in the Kara/Barents west of SZ will now, probably, allow warm surface currents earlier access to the Laptev.

17
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 15, 2019, 02:06:50 PM »
On the more optimistic side, large floes are finally compacting into NE Svalbard. They have a few days before the wind changes to make an attempt at fast ice.

Worldview, viirsbt15n, atlantic front, mar7-15, ascat mar7-14 inset.

A tiny chip off the Nares polynya, bottom left (see https://forum.arctic-sea-ice.net/index.php/topic,2592.msg192004.html#msg192004)

18
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 14, 2019, 04:35:55 PM »
There's a nice volume chart here for the CAB https://forum.arctic-sea-ice.net/index.php/topic,2348.msg191848.html#msg191848

Worldview viirs brightness temperature of the thickest ice north of CAA, mar7-13.
They say 'the bigger the cracks, the thicker the ice'. https://go.nasa.gov/2JbQ3PV

Polarview images of the same CAA ice close to the coast in no particular order. https://www.polarview.aq/arctic

19
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 14, 2019, 02:29:41 PM »
Comparison of ascat with cs2smos merged sea ice thickness for mar10. (8bit colour for the animation)
Cryosat2 not impressed with the old ice near FJL/SZ.

20
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 14, 2019, 12:36:08 AM »
update on mercator 34m salinity, jan1-mar12

21
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 13, 2019, 09:42:03 PM »
I've been looking at 105 again.
Some data for whoi itp105. It appears to be programmed to collect 3 profiles down to 250m then 1 down to 800m if it has time or doesn't have a problem. That makes it tricky to match up dates with my simple coding skills so I haven't attempted to combine much.
Firstly, the location data. For the timeline in the image you posted it doesn't look like it makes repeated passes. (or maybe it does, please check)
2. Temperature and salinity from 300-800m (some days have no data) click on the image to run
3. Temperature and salinity from 0-250m. Had to go to mp4 to keep the size down.

edit: last profile was mar9. Hope it comes back.. Forgot whoi itp105 location and profile.

22
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: March 13, 2019, 10:32:43 AM »
Attached is the volume for the CAB only. <snippage>
Nice chart, are they piomas numbers?
This may not be a 'balance' but a temporary pause while MYI and 2 year ice is flushed out.

23
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 12, 2019, 09:45:03 PM »
Slowpoke could well be a resident for quite some time. I had trouble finding the disparate matched pair but I think I identified the remnants. Worldview, mar7-12.

24
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 10, 2019, 11:08:13 AM »
amsr2, okhotsk, mar1-9. I hadn't noticed that warm spot in the middle before. Freezing is occuring some distance from the coast, probably due to upwelling as the fairly constant northerly winds have been cold. Or perhaps the freeze just struggles to keep up with the drift, see worldview https://go.nasa.gov/2J2dxab

added worldview, terra modis, feb10-mar10
I think this animation is typical of sea ice formation in rough seas, something we will probably see a lot more of next year freezing season on the eurasia side of the arctic. https://en.wikipedia.org/wiki/Sea_ice#Formation
Quote
In rough water, fresh sea ice is formed by the cooling of the ocean as heat is lost into the atmosphere. The uppermost layer of the ocean is supercooled to slightly below the freezing point, at which time tiny ice platelets (frazil ice) form. With time, this process leads to a mushy surface layer, known as grease ice. Frazil ice formation may also be started by snowfall, rather than supercooling. Waves and wind then act to compress these ice particles into larger plates, of several meters in diameter, called pancake ice. These float on the ocean surface, and collide with one another, forming upturned edges. In time, the pancake ice plates may themselves be rafted over one another or frozen together into a more solid ice cover, known as consolidated pancake ice. Such ice has a very rough appearance on top and bottom.
Though I think frozen sea spray may also play a large part in the cooling process.

25
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 08, 2019, 07:14:38 PM »
Travelling so can't contribute. Thanks for the updates and the pleasant OT.

26
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 05, 2019, 10:12:18 PM »
Sometimes you have to believe in the music and not worry about the audience participation Tor.
Despite voting option2 I don't think that tiny break from the polynya is a win. I was thinking more of this...

27
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 05, 2019, 09:54:59 PM »
@ Ktb While you are enthusiastic why not add volume as well?  :)  hmm, though maybe not on this thread

28
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 05, 2019, 09:16:06 PM »
ok, no paygrade excuses then  ;) or we all get a rise  :) . I looked at itp53 http://www.whoi.edu/page.do?pid=157836 which is a prime candidate for 2012, but it requires a bit of recoding as the file format has changed. It would be interesting to compare though.

Regarding the lomonosov ridge there have been many parallel fractures this freezing season. I didn't notice them so much last year and viirs brightness temps aren't available before then. They would have to be pretty big to show up on ascat.

I guess that mixing is more likely to occur with shallow density gradient.

29
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 05, 2019, 01:42:46 PM »
Stayed with ITP110 to look at density compared with temperature from 0-150m (to keep Bruce Steele interested ;) )
The build up in temperature from 40-100m in some areas speaks for itself. It's above my pay grade to comment further.
Up and down profiles shown

30
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 05, 2019, 12:10:10 AM »
Thanks johnm33. A suggestion to look at density led me to the ocean water density calculator.
Density in kg/m3 (cubed) for ITP110


http://www.csgnetwork.com/water_density_calculator.html
Quote
The equation used in this calculator can be found in:
Millero, F, C. Chen, A Bradshaw, and K. Schleicher, 1980: A new high pressure equation of state for seawater, Deep Sea Research, Part A, 27, 255-264.
doi:10.1080/15210608209379435

I may have time to look at 107 again tomorrow

31
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 04, 2019, 04:38:59 PM »
Mobile ice still struggling in the warm current north of FJL despite the cold air temperatures.
Worldview, viirsbt15n, feb12-mar4   https://go.nasa.gov/2IRqsvl

32
Arctic sea ice / Re: The 2019 melting season
« on: March 03, 2019, 10:28:10 PM »
Worldview, terra modis, Beaufort, feb28-mar2.

33
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: March 03, 2019, 12:15:03 AM »
Yes, thanks, the Bering Strait is too shallow. ITP110 shows the most regular disturbances at depth. 20-30 day intervals. That could also be due to circular drift over relatively stable currents though.



34
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 02, 2019, 11:47:33 PM »
Meanwhile, there is still movement in the Nares straight at both ends. <snippage>
Iain, you might like to vote on the Nares new old ice poll, open till Mar5
https://forum.arctic-sea-ice.net/index.php/topic,2592.0.html

35
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 02, 2019, 10:58:37 PM »
Shame about the clouds but it is possible to follow the floes down the strait and it is quite a race. I hope I have identified the stragglers correctly.
Worldview viirsbt15day feb27-mar2

36
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 01, 2019, 09:26:34 PM »
Thanks for the poll Tor.
Recent wound refractures just after the floes enter the Kane basin.

37
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 01, 2019, 12:46:33 PM »
ascat and amsr2-uhh sep17-feb28.

38
Arctic sea ice / Re: The 2018/2019 freezing season
« on: February 28, 2019, 10:34:06 PM »
Mercator 0m salinity, Bering to Kara, jan-feb for background info.

39
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 28, 2019, 09:53:12 PM »
Here looking at the path of whoi ITP107, data in previous post, overlaid onto Mercator 34m salinity. Still some inaccuracies in the scaling (shown in the final frame) as lat/long hasn't been converted to the correct projection yet.
Apparently not as close to the choppy Chukchi waters as I had thought, if Mercator model is correct. Good news if it goes round again (and the traction drive is ok).


40
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 28, 2019, 05:41:28 PM »
<>I'm reading the white intrusions as off the scale, not faults,<snippage>
I don't think the white areas are off the scale. It looks like the profiler stops moving up and down the wire, possibly because the current is too strong. With its proximity to the Chukchi, isn't it more likely that the latest currents are related to the pulses from the Bering?

Some extracts from the whoi ITP technical description. http://www.whoi.edu/page.do?pid=20777

Quote
The profiling underwater unit is similar in shape and dimension to an
ARGO float except that the float’s variable-buoyancy system is replaced with a traction drive
unit.
Larger motor currents are observed at times of fast ice floe motion when larger
wire angles develop and drag forces on the profiler are increased.

A 250 lb ballast weight (made of 50 lb plates to facilitate transportation) is fixed to the
bottom wire termination to add tension to the wire and minimize its catenary. The WHOI
CABLE model (Gobat and Grosenbaugh, 2000) was used to determine the attitude of the ITP
mooring due to 25, 38, and 51 cm/s ice floe drift speeds using several different wire lengths. The
model predicts about 5 m of vertical uplift of the bottom termination at 25 cm/s, about 32 m at 38
cm/s and about 85 m at 51 cm/s. Horizontal displacement of the bottom termination is indicated
to be about 100 m, 220 m, and 350 m, respectively. To accommodate the catenary of the ITP
mooring at times of ice floe drift speeds up to 35 cm/s, 25 or 30 m of extra cable (beyond the
programmed maximum profiling depth) is needed. So mooring cables of about 790 m length
should allow for profiles as deep as 760 m in the vast majority of ice drift conditions. At the
extreme instances when drift rates approach 51 cm/s drift, it may be impossible for the profiler to
climb the wire against the current, making the maximum depth of the tether moot.

whoi itp107 location, temperature and salinity jan-feb  (click to run)
whoi itp location and profile contours feb28


41
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 27, 2019, 11:03:23 PM »
thanks johnm33

<>Does anyone have any idea how this extra heat and volume will dissipate ?
Probably not but as we're on the cusp of the freezing/melting season here are some options....

1. It's a 'one off' that slowly fades away by mixing, adding to general AGW.
2. It's perennial and layer thickness and temperature increase yearly, eventually warming surface layer and reducing ASI.
3. Without the thick ice 'governor' the gyre spins up to unstable speed, the freshwater layer slips off into the CAB at the end of the melting season and freezes in place up to 20m thick. The warm layer radiates into space in clear skies and gives us another 10 years to save the planet. Marvel make a film about it. ;)
4.....your own wild guess
didn't mean to imply your ideas were wild Bruce Steele


edit: incoming from bering/chukchi or upwelling?
Worldview, terra modis, Beaufort feb27

42
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 27, 2019, 12:14:02 PM »
<>
 Take a look at this, zoom in and decide if the twists in the waves are artifacts or real,<snippage>
johnm33, do you have a link for arctic wide hycom compressional strength? Beaufort only catches the edge of these...

43
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 27, 2019, 11:56:53 AM »
That fracture has closed. Yes, perhaps it will heal with light winds.

44
Arctic sea ice / Re: Guess the date of the max
« on: February 27, 2019, 01:05:43 AM »
I hope the logic works out oren, but the first 10 days of those 21 don't look too promising.
Windy ecmwf temperature forecast feb27

45
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 26, 2019, 10:33:42 PM »
Probably, though I think that fracture will provide a few more chunks. Any one still betting?  :)

46
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 26, 2019, 10:07:21 PM »
A closer look at floes attempting to approach Svalbard, feb25-26 (some clouds)

47
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 26, 2019, 09:27:38 PM »
Mercator model doing quite a good job matching 34m temperature to Suomi npp/viirs on the atlantic side, feb26.

48
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 26, 2019, 08:06:19 PM »
Not expecting an answer  ;)
Tor may be right. New fracture today.  https://go.nasa.gov/2GLZ5RC

49
Arctic sea ice / Re: The 2018/2019 freezing season
« on: February 26, 2019, 01:21:06 PM »
#byebyebering
Probably. Some ice in the Gulf of Anadyr may survive the upcoming warm spell but, like last year, the new ice in open water has no resistance to air temperatures down to -5C(ish). Southern Chukchi also very weak. Meanwhile thicker ice on the Atlantic side heads for the exit.

Refreeze on the coast of the Anzhu islands (laptev/ess), feb12-26, worldview viirsbt15d and terramodis.
click on image to run.

50
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 26, 2019, 12:18:54 PM »
But why the larger encatchment area? Stronger current? higher tide? Thinner ice? Full moon? SSW mslp? Warmer water from depth?
It was a very cold winter in the Lincoln Sea.

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