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Messages - uniquorn

Pages: [1] 2 3 ... 12
1
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 16, 2019, 02:27:37 PM »
A further look at the amsr2 representation of ice on the atlantic front over the last few days where refrozen fractures show as higher concentration than older floes. This is apparent on both uni Hamburg and Bremen.
Comparing with worldview viirs, brightness temperature(band 15,night) with different palettes (green1 and rainbow1) there is a haze above the refrozen fractures, more visible on the rainbow palette. Perhaps it is mist due to heat escaping through the thinner ice. Snow would be unlikely where the ice meets the ocean.
worldview,viirs,bt15n,jan16  https://go.nasa.gov/2TWCNzh
amsr2-uhh, jan15 - high contrast on right

2
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 16, 2019, 01:23:15 AM »
This animation is so messy that I wasn't going to post it, but I think it shows how volatile ice extent/area is over recent years, particularly when the peripheral seas are freezing.
amsr2-uhh, dec1-jan13 from 2015/16-2018/19

3
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 15, 2019, 12:58:58 PM »
The warm current north of Svalbard dominates the ice on the atlantic front despite the cold winds from the SSW. Cloud streams highlight the temperature difference (estimates: air ~-30C, water ~2C) and wind direction. Acceleration of ice towards the Fram Strait opening up the already numerous fractures all the way to the Lincoln sea.

4
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 15, 2019, 12:21:58 PM »
January 6-13.
Not sure what makes amsr2 detect large floes as lower concentration than the 'glue ice' in between. Snowdrifts?
With the cold wind, I'd expected the ice to cross the warm current to Svalbard again but no, it still melts.
amsr2-uhh, atlantic front, jan7-14
worldview, viirs, bt15n, atlantic front, jan15  https://go.nasa.gov/2FvSg66

5
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 12, 2019, 12:26:43 PM »
Shame, would have spurred some interesting reading had it happened.

Forgive my naivety.
thanks for the research  :)  It's unlikely that this year's mostly first year ice is up to the job. Waves are over 3m today, forecast for over 4m tomorrow.
polarview, Greenland ice front closest to Jan Mayen, jan12 

6
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 11, 2019, 11:29:05 PM »
no

7
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 11, 2019, 12:10:27 PM »
Pretty sure that's not ice round Jan Mayen. Dense cloud perhaps. Some goodbye waves visible to the far left of the polarview image.
amsr2, east greenland, jan10
polarview, jan mayen, jan10

8
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 11, 2019, 11:55:25 AM »
Looking a bit weak beyond the next arch.
Worldview,viirs,bt15,night,jan9-11

9
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 09, 2019, 03:42:04 PM »
Indeed, and I believe some of the push back is actually strong melt, as evidenced by movement of coarse features compared to the speed of retreat, especially on the last frame.
The Atlantic is fighting back.
agreed. Polarview, svalbard, this morning. Sorry, not much ice in this image, mostly wind blown slush. https://www.polarview.aq/arctic for more images.

10
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 09, 2019, 12:05:01 PM »
The cyclone in the Greenland Sea -> Barents will probably drag a lot of ice (and cold air) back towards Svalbard.
edit:added wind and temp. Windy ecmwf jan9 forecast for jan11

11
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 09, 2019, 11:32:50 AM »
Atlantic current beneath the ice on it's way to the Laptev.
Worldview, viirs,bt15,night,jan7-9.
Mercator 34m salinity, jan7

edit: polarview image, jan11 for future reference.

12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 08, 2019, 02:10:49 PM »
Less cloud today. worldview,viirs,bt15n, northFJL, jan7-8.

ascat, day325-007. (3.6MB)
Hopefully ice on the Pacific side will be less mobile now the Bering Strait is plugged. The Beaufort arc of older ice bifurcated at the Chukchi while there was open water. The atlantic ice front made it to Svalbard only to be pushed back, possibly temporarily. Fast moving, quite fragile ice in the Greenland Sea due for another pounding tomorrow and 957 949hPa cyclone gfs forecast for thursday before thicker ice from the CAA makes its way across in the next few days (see Tealight https://forum.arctic-sea-ice.net/index.php/topic,2268.msg185799.html#msg185799).

windy ecmwf forecast for jan10
hmmm. 11m waves, >90km/h wind forecast along the Greenland sea ice front on friday. Like Meddoc (sort of) says, maybe a large short term extent gain coming.

13
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 07, 2019, 12:14:06 PM »
The warm current apparently still at work under the ice north of FJL.
Worldview,viirs,bt15n,jan5-7 see next post

14
Arctic sea ice / Re: "Stupid" Questions :o
« on: January 07, 2019, 11:55:42 AM »
<snippage>
Is there a format we could follow that would be acceptable to members here?

Suggestion: ASIF et al and a link.
It is A team effort after all.

15
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 06, 2019, 08:39:35 PM »
New fractures. edit: Worldview,viirs,bt15,night,jan6-7  https://go.nasa.gov/2FcfPR7

16
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: January 06, 2019, 07:38:48 PM »
I wouldn't like to stray off topic for too long but I haven't improved anything. Only rediscovered what should have been done all along....

Quote
This amounts to land-masked framen of (R,G.B) = (dayn - dayn-1, dayn - dayn-2, dayn - dayn-3) - (50,50,50)) after contrast renormalization, adaptive histogram equalization and bicubic rescaling
Sorry that didn't paste too well.  'Ascat interferometry' looks really useful.
Is there any chance of a slightly more step by step description of this process? I'd like to try to compare this year to previous years.

It will be interesting to run the correct method on the post SSW weather.

17
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 06, 2019, 11:28:25 AM »
Kara Sea trying to freeze. Polarview jan6

Also a good view of the Bering Strait today on Worldview, viirs,bt15,night.

18
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 06, 2019, 10:53:37 AM »
Update on the whoi ITP buoys. http://www.whoi.edu/page.do?pid=163197
ITP103 showing a steady increase in salinity at depth
ITP104 showing a steady increase in salinity at depth (recent data may smooth out)
ITP105 no profile since jan2. Dec31 profile showed a lesser increase in salinity at depth
ITP107 decrease in salinity to ~50m confirming gyre
ITP109 decrease in salinity to ~50m confirming gyre. 50m-100m warm layer
ITP110 confirming 50m-100m warm layer

edit:no further reports from the argo float yet

19
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 05, 2019, 04:31:03 PM »
Polarview image north west of Svalbard jan5 showing some of the area of warm atlantic water upwelling and what may be evidence of surface currents.

Nullschool version of surface currents jan5.

20
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: January 04, 2019, 11:43:38 PM »
Uniquorn,
The animation on the right makes me think it is showing waves, rather than just ice movement.  When a crack opens up, the crack moves/changes slowly but the waves stream along it.
Yes, or a weather system moving overhead.

21
Arctic sea ice / Re: AMSR2 Sea Ice Volume/Thickness
« on: January 04, 2019, 08:28:40 PM »
Comparison of Tealight's amsr2sit and 1day interference on ascat during december 2018.  Each interference image is created by combining images from three consecutive days in RGB, highlighting ice movement.
As the band of thinner or lower concentration ice along the old ice line is still visible on both animations, perhaps it is caused by the difference in movement of thicker and thinner ice.

edit:slowed the animation to 3days/s

edit:While talking my wife to sleep (helps insomnia apparently) I realised the interferometry animations were incorrect. Apologies to A-team whose method combines d1,d2 d2,d3 and d3,d4 but the last few I have posted combined d1,d2 d2,d3 and d1,d3 which compares 3 days, not 4 and over different time frames. While correcting the error I tried comparing d1,d2 d1,d3 and d1,d4 which seems to improve definition of the old ice line. I've updated this animation with latter version. Sleep well.

22
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 04, 2019, 10:33:01 AM »
This wind driven advance may be overstretching the pack a little. Hopefully the refreeze will keep up.
Worldview, viirs, bt15,night, jan4.  https://tinyurl.com/y8kan8n5

edit: viirs has been available since sep17 so added jan4,2018 for comparison. More ice (extent) but probably thinner, particularly in the Lincoln sea (left). edit: Though Tealight has Lincoln Sea at 3m so perhaps not thinner.
https://forum.arctic-sea-ice.net/index.php/topic,2268.msg185737.html#msg185737

All of the peripheral seas also increased in extent yesterday.
https://sites.google.com/site/arcticseaicegraphs/regional

23
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 01, 2019, 06:52:31 PM »
It's been a quiet couple of months on the north Greenland coast compared to the last 4 years. Here we are looking for signs of upwelling by increasing contrast to highlight low concentration on amsr2-uhh. Wind driven 'lift off' of ice from the coast is apparent in 2014, 2016 and 2017 but no conclusive evidence of increased upwelling this year.
amsr2-uhh, nov11-dec31, 2014-2018.
days are not quite synchronised due to missing some missing data

edit: Today's worldview image of nth greenland for comparison https://tinyurl.com/ydxhk7sc

24
Arctic sea ice / Re: The 2018/2019 freezing season
« on: January 01, 2019, 12:56:51 PM »
SST's from the argo float are here
https://forum.arctic-sea-ice.net/index.php/topic,2417.msg184302.html#msg184302
though it hasn't surfaced since dec14 (or batteries may be flat).
Agreed, evidence of melt as far as FJL. Worldview, viirsbt15n, dec23-jan1. (3MB)

On a brighter note, Bering sea is freezing.
amsr2-uhh, dec1-31. (1.4MB)


25
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 31, 2018, 03:08:52 PM »
Agreed. The ice north and north east of Svalbard looks fragile. The wind is forecast to change jan2.
amsr2-uhh, atlantic front,dec24-31

26
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 31, 2018, 12:26:41 PM »
Ice on the Atlantic front reaches the Svalbard Islands.
Worldview, Atlantic ice front, viirs,bt15n, dec31 (click on image for full size)
Polarview, Svalbard, dec31

27
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 30, 2018, 05:56:16 PM »
Laptev Sea, amsr2-uhh default and high contrast, oct23-dec29.
Using Mercator 34m salinity here to compare with the underlying current from the atlantic.
salinity scale same as above

28
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 30, 2018, 11:13:35 AM »
A 974hPa cyclone over the Kara tomorrow might spread the ice around a bit.
Wipneus regional sie, Kara, dec29.
https://sites.google.com/site/arcticseaicegraphs/regional

29
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 29, 2018, 12:18:39 PM »
<snippage>Greenland Sea - export down the Fram?
amsr2-uhh and jaxa, Greenland Sea, nov9-dec27

30
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 28, 2018, 11:22:40 PM »
Yes, the ice front may make it across to Svalbard over the next few days.

An animation of the Kara/Barents using uni hamburg amsr2, oct18-dec27, 7days/sec (~3MB)


31
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 28, 2018, 11:02:24 PM »
A closer look using worldview, viirs, bt15n, dec23-28.
Low concentration area in the centre, Svalbard far right. Winds are forecast from the west for a few more days so the ice front may reach across the warm current to Svalbard again this year.  The cloud streets thickening up with the increasing temperature difference perhaps.

32
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 28, 2018, 12:42:13 PM »
Update on the persistent low concentration area north of Svalbard.
amsr2-uhh, aug1-dec28, contrast enhanced on rhs.

33
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 25, 2018, 04:17:24 PM »
same old same old.
bon fete :)

34
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 23, 2018, 05:57:47 PM »
967hPa forecast for north west of SZ tomorrow. Ice on the western corner already looking quite weak.
Worldview, viirs, bt15day, dec23 and windy ecmwf pressure 0m dec23 forecast for dec24

35
The rest / Re: Astronomical news
« on: December 21, 2018, 04:57:37 PM »
Mars Express beams back images of ice-filled Korolev crater
A composite picture of the Korolev crater in the northern lowlands of Mars, made from images taken by the Mars Express High Resolution Stereo Camera overlaid on a digital terrain model. Photograph: Björn Schreiner/FU Berlin/DLR/ESA

The stunning Korolev crater in the northern lowlands of Mars is filled with ice all year round owing to a trapped layer of cold Martian air that keeps the water frozen.
The 50-mile-wide crater contains 530 cubic miles of water ice, as much as Great Bear Lake in northern Canada, and in the centre of the crater the ice is more than a mile thick.

https://www.theguardian.com/science/2018/dec/21/mars-express-beams-back-images-of-ice-filled-korolev-crater

36
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 21, 2018, 12:28:44 PM »
Using mercator 30m salinity here to show the Atlantic current in the Kara Sea. Note the old ice dipping north west of SZ. Didn't really find what I was looking for but posting it anyway for background info.
ascat, smos uni-bremen, mercator 30m salinity, oct17-dec20

37
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 20, 2018, 11:12:34 PM »
Thank you Brigantine.
Update on the whoi ITP buoys. ITP103-5 not drifting much. ITP107 and 109 reporting very low salinity down to ~50m nearer the gyre and 109 still reporting the thick layer of warmer water from ~50-100m with 107 and 110 possibly indicating the boundary of that layer. (will have to look more closely at the data sometime to show that)
Looking at the path of ITP109 compared to mercator model 92m temperature suggests the warm layer is from the Pacific.

whoi ITP103-110, dec20
mercator model 92m temperature, oct1-dec20 edit: should be rotated to match whoi map
mercator model 92m scale

38
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 20, 2018, 11:58:48 AM »
Large floes meet the warm current and warm(ish) winds on the ice edge north east of Svalbard, dec18-20 (19th cloudy) The large floe in the centre right on the 18th is was ~20km top to bottom.
Worldview, viirs, bt15n.
edit:  https://tinyurl.com/y7e7c47e

39
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 19, 2018, 10:34:23 PM »
Quite a clear view of the Chukchi today on worldview.   https://tinyurl.com/ya43cwu6

40
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 18, 2018, 12:05:10 PM »
The argo float must have gone back to a weekly cycle hopefully. Nothing new since 14th.
It should be down there somewhere.
Worldview, viirs, bt15n, dec18 with amsr2-uhh, dec17 inset. North of FJL, more choppy weather coming up.

41
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 17, 2018, 12:21:03 PM »
Worldview, viirs,bt15n,dec16-17.  https://tinyurl.com/y75x8uxf
Westerly winds pushing large floes into the warm current north of Svalbard. Low concentration ice above the possible upwelling (just above centre) looks more like a whirlpool. Quite a turbulent forecast for this area tomorrow.

42
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 16, 2018, 02:44:56 PM »
An amateur attempt to match argo float 3901910 to amsr2-uhh to see how close to the ice edge it travelled, aug18-dec14. It reported weekly until december and has been reporting daily since. Report (cycle) numbers are overlayed onto Greenland, bottom left.
The main observation is that the warm current alongside the ice front is ~2.5C at surface recently.

More details and data here https://forum.arctic-sea-ice.net/index.php/topic,2417.msg184302.html#msg184302

edit: "These data were collected and made freely available by the Coriolis project and programmes that contribute to it (http://www.coriolis.eu.org)."


43
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 16, 2018, 12:53:29 PM »
An amateur attempt to match argo float 3901910 to amsr2 to see how close to the ice edge it travelled, aug18-dec14. It reported weekly until nov30 and has reporting daily since. Report (cycle) numbers are overlayed onto Greenland, bottom left.
edit:added temp labels

Approximate data based on eyeballing the attached charts is in text below. Timing the temp/salinity data to the animation makes the gif too large. Easiest to download both gifs and step them manually for analysis. (or even better, advice from someone with netcdf skills pls)

The main observation for ice watchers is that the warm current alongside the ice front is ~2.5C at surface recently.

cycle   lat              long          temp C    sal      date
60   80.06547      5.16783      2.75      32.4      0818
61   80.20849      5.23104      5      34.45   0825
62   80.38986      4.78623      2.6      33.65   0901
63   80.48555      6.0284      4.5      34.42   0908
64   80.49247      6.82373      3.8      34.1      0915
65   80.58095      7.16061      4.3      34.1      0922
66   80.44863      8.30625      3.8      34.4      0929
67   80.43952      9.16231      4      34.75   1006
68   80.37718      7.56771      1.5      34.4      1013
69   80.51731      11.28802      0.3      34.1      1020
70   80.84061      14.77375      3      34.75   1027
71   80.85687      16.35878      1.5      34.6      1103
72   81.43671      17.30993      1.6      34.64   1110
73   81.56787      21.71607      -1.2      34.15   1117
74   81.61883      26.34895      -0.7      34.35   1124
75   81.62392      31.29192      -1.5      34.26   1201
76   81.82774      34.03102      -1.1      34.32   1202
77   82.01424      35.80637      -1.6      34.26   1203
78   82.1778      38.04842      2.5      34.82   1204
79   82.28333      39.82095      -1.6      34.23   1205
80   82.29029      39.77042      2.3      34.77   1206
81   82.28489      39.64985      1.8      34.74   1207
82   82.29791      39.56938      2.7      34.86   1208
83   82.25532      39.58456      0.8      34.61   1209
84   82.22805      39.50098      2.7      34.86   1210
85   82.20667      39.35864      2.5      34.86   1211
86   82.21352      39.10944      1.2      34.45   1212
87   82.21687      39.05996      -1.2      34.29   1213
88   82.21415      39.16856      0      34.49      1214

data here http://www.argodatamgt.org/Access-to-data/Description-of-all-floats2
choose 3901910

44
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 13, 2018, 10:36:22 PM »
Thanks to Brigantine for the heads up on the ARGO float 3902910 currently north of FJL.
The first image shows the drift trajectory and the cycle (report) number. The projection could be better for the arctic but Svalbard is clearly identifiable centre left, FJL under the 80N text.

The animation shows temperature and salinity charts for cycle 65,70,73 and 83-87 (latest). From my limited understanding of the charts, this float appears to have drifted along the ice front in the warm current at depth, surfacing sometimes into cold meltwater, other times into the warm current.
2 days ago SST was 2.5C salinity34.85, today -1.6C salinity 34.15

http://www.argo.ucsd.edu/How_Argo_floats.html
Quote
Argo is an international collaboration that collects high-quality temperature and salinity profiles from the upper 2000m of the ice-free global ocean and currents from intermediate depths. The data come from battery-powered autonomous floats that spend most of their life drifting at depth where they are stabilised by being neutrally buoyant at the "parking depth" pressure by having a density equal to the ambient pressure and a compressibility that is less than that of sea water. At present there are several models of profiling float used in Argo. All work in a similar fashion but differ somewhat in their design characteristics. At typically 10-day intervals, the floats pump fluid into an external bladder and rise to the surface over about 6 hours while measuring temperature and salinity. Satellites or GPS determine the position of the floats when they surface, and the floats transmit their data to the satellites. The bladder then deflates and the float returns to its original density and sinks to drift until the cycle is repeated. Floats are designed to make about 150 such cycles.

data here http://www.argodatamgt.org/Access-to-data/Description-of-all-floats2
choose 3901910

"These data were collected and made freely available by the Coriolis project and programmes that contribute to it (http://www.coriolis.eu.org)."
edit: slowed the gif a bit

45
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 13, 2018, 12:16:29 PM »
Per CIS, the Parry Channel is mobile again.

Also, there's this one ARGO float sitting in the warm current NE of Svaalbard (~82N 39E).
It's taking profiles every day, and it's quite Atlantified there.
Thank you Brigantine. Mclure Strait looks frozen but there is movement further south.
Will look at the ARGO float on the salinity thread. That looks worse than I thought.

ecmwf wave forecast dec13-22 from windy
edit: ~82N 39E is the northernmost open water top right, north of the westernmost FJL island.
added scale

46
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 12, 2018, 01:06:38 PM »
In fact the entire Atlantic front + Kara seems to be increasing.
That's one way of describing it.  Worldview link, https://tinyurl.com/y6wyep2b

47
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: December 11, 2018, 11:31:06 PM »
So the big floe looks like it popped out like a cork over the last 3 days.
Worldview, viirs bt15n, dec5-10
Polarview dec11

48
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 11, 2018, 10:48:58 PM »
Shearing along the Lomonosov ridge line, north of the Nares Strait.
Worldview, viirsbt15n, dec9-11

edit:cropped it down a bit

49
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 11, 2018, 06:34:05 PM »
The ecmwf wave forecast on dec3 wasn't too bad that far out, though there are pretty large waves most days at the moment. Barents/Kara getting a battering tomorrow but not the CAB.
windy ecmwf wam dec12

edit:
Polarview image yesterday of lower concentration ice north of FJL. Mercator 0m salinity and amsr2-uhh ice concentration inset.

50
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: December 10, 2018, 04:45:14 PM »
Update on Mercator 0m salinity model showing an atlantic push eastward during the recent stormy weather, possibly causing upwelling on the southern Kara sea coast.
The model also indicating upwelling on the CAA/Beaufort and Chukchi coast. I don't know if the increase in salinity along the CAA is due to brine exclusion or upwelling. Wind driven lift off from the coast is visible on Worldview, but it's been very cold so it's likely the fast ice has been weakened from below. Comments very welcome.
Mercator 0m salinity, nov20-dec9 (scale same as above)

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