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Messages - uniquorn

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1
Arctic sea ice / Re: The caa-greenland mega crack
« on: December 06, 2019, 01:38:35 PM »
significant shear, https://go.nasa.gov/38eGIiQ   cffr

2
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 30, 2019, 03:32:43 PM »
Here using mercator (model) salinitytemperature at 34m to show currents at 34m that may help to explain the resilience of the extended Chukchi bite. Sep21-nov29. Turbulence along the edge of the chukchi plateau is likely to increase mixing of shallow water.

3
Arctic sea ice / Re: MOSAiC news
« on: November 29, 2019, 01:26:58 PM »
drift update, 3 Pbuoys closest to PS - see below

4
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: November 27, 2019, 10:23:15 PM »
uni-hamburg amsr2-uhh overlaid onto mercator temperature 0m at 80% transparent. amsr2 0% concentration, normally dark blue, has been set to fully transparent. Chukchi, sep21-Nov26, Large.
Posting temporarily - removed

5
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 27, 2019, 10:04:48 PM »
uni-hamburg amsr2-uhh overlaid onto mercator temperature 0m at 80% transparent. amsr2 0% concentration, normally dark blue, has been set to fully transparent. Chukchi, Nov1-26

6
Arctic sea ice / Re: MOSAiC news
« on: November 26, 2019, 05:09:24 PM »
that drop has potential for development :)
Quote
Manipulating the longitude in the dataset prior to conversion
Went with lon = (data$longitude..deg. +45), lat = data$latitude..deg.    from the line before which appears to have the desired effect, though doesn't affect the underlying map, as you say. Should be ok till they hit land (and no bathy)

So, we have rotation and lat/lon labels. You wait ages for a lucky click and then 3 come along at once. And then music.

That manually placed 86N label is at 86.1 Will fix it and repost later(see below)

Tech note: Lat/Lon data is to 3 or 4 decimal places, rounded here for visual reasons. There are still some overlaps.
Forgot to change lon lines so 120E is not shown. Check the numbers


7
Arctic sea ice / Re: MOSAiC news
« on: November 24, 2019, 07:29:32 PM »
<If the Rammb is enlarged 3x but its PS held at the PS S1 location>
Maybe that should be from the projected PS loc for nov23

A major breakthrough for the buoy animations today. We now have dates! Though please see below for a view on how accurate they may be. This one goes back to nov17 to show todays movement retracing the previous path. We also have minimal manually added lat/lon labels.

Tech note: Best efforts are made to make the frame count the same as the number of hours, so the time should be accurate to the hour, probably much closer.
Quote
transition_along makes the following variables available for string literal interpretation, in addition to the general ones provided by animate():
    frame_along gives the position on the along-dimension that the current frame corresponds to
https://rdrr.io/github/dgrtwo/gganimate/man/transition_reveal.html
I would never have guessed 'frame along' in a million years, but, eventually, after asking the right question....



Some background on the method used for the buoy animations
Quote
When we animate data visualisations we often do it by calculating intermediary data points resulting in a smooth transition between the states represented by the raw data. In gganimate this is done by adding a transition which defines how data should be expanded across the animation frames. Underneath it all most transitions calculate intermediary data representations using tweenr and transformr — so far, so good.

What we have glanced over, and what is at the center of the problem, is what state of the data we decide to use as basis for our expansion. If you are not familiar with ggplot2 and the grammar of graphics this might be a strange phrasing — data is data — but if you are, you’ll know that data can undergo several statistical transformations before it is encoded into a visual property and put on paper (or screen).
https://www.data-imaginist.com/2018/what-are-we-plotting-what-are-we-animating/

8
Arctic sea ice / Re: MOSAiC news
« on: November 24, 2019, 02:55:08 PM »
helicopter trip?

9
Arctic sea ice / Re: MOSAiC news
« on: November 23, 2019, 01:16:16 PM »
update on close buoys, nov19-23. The diagonal to the legend is 120E with 2deg intervals, the line top right is 85.5N, with 0.1deg intervals. No labels. Testing semi transparent buoy markers.
Westerly buoys get two northerly lurches, the easterlies only one.

10
Arctic sea ice / Re: MOSAiC news
« on: November 23, 2019, 01:15:11 AM »
Wide area view from Sentinel1AB with merged intermediate frames at 50%, nov17-22. No buoys yet.
click to run
scale=30% to reduce size

11
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 20, 2019, 08:56:16 PM »
A possible mechanism for correlation of bathy with summer ice edge from Svalbard to FJL and possibly to SZ. The first animation shows this year's ice drift from oct1-nov18. The east oops, west spitsbergen current is probably not in doubt on this thread. It's effects can be seen on the surface clearly at times during the animation and, in my view, also beneath the ice as leads or lower concentration up until the line where the 'warm water waterfall' falls into the Nansen basin. There may be some mixing but I think the dense, high salinity water sinks quickly to at least 75m, taking the heat with it. edit: Ice colour, normally white, has been inverted to make it easier to see the bathymetry.
2018 from here was a better example but you have to imagine the bathy and forgive the very basic science. Studying that particular argo float data in detail may answer some questions (or raise many many more) 

12
Arctic sea ice / Re: MOSAiC news
« on: November 20, 2019, 11:47:32 AM »
Quote
Here the time series are using 26 rolling weekly averages according to the Cryosat2 freeboard  / Smos thinness merger of observational ice thickness
Nice analysis
Quote
there's no long term consistent data set using these satellites and the refined merger algorithm.
The merged cryosat2-smos v2.02 data appears to go back to nov2010 at AWI (someone's been busy :) ) so a mid term comparison could perhaps be made.

It's been a long journey through google, guesswork, commas and brackets to buoy labels. Today I got the lucky click. So, an update on drift speed of the meereis Pbuoys closest to Polarstern from nov14-20, latest data at ~04:00, with labels. (temporarily without tails)

edit: Polarstern is currently roughly half way between p204 p201 and p207. The buoy on the edge of the floe 'fortress' STIPAKAF ;) is not shown here.
somewhat thicker ice previously also known as fortress

Added an overlay of Pbuoys with labels near Polarstern, circled in red, on today's S1B 04:24 image. The buoy colours just happen to be inverse of drift speed of a much shorter animation. It was an easy way to make them more visible. Click for full resolution.

13
Arctic sea ice / Re: MOSAiC news
« on: November 19, 2019, 08:41:00 PM »
update on drift speed of the meereis Pbuoys from nov14-19 ~04:00

I took P101 out though it's still sending data sporadically.
(see animation below)

14
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 18, 2019, 09:45:26 PM »
A reminder of minimums and bathy since 2012. I would say there is some correlation on the atlantic side.

15
Arctic sea ice / Re: MOSAiC news
« on: November 18, 2019, 06:38:46 PM »
update on drift speed of the meereis Pbuoys from nov14-18 ~03:30

Posting this for interest while I work out which is the wayward buoy in the middle.

16
Arctic sea ice / Re: MOSAiC news
« on: November 17, 2019, 07:03:53 PM »
update on drift speed of the meereis Pbuoys from nov14-16 ~11:30

see below

17
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: November 17, 2019, 06:38:22 PM »
I wish I knew Niall.
Whoi itp buoys in the Beaufort for reference. Maybe those thick warm layers at 25m are starting to make a difference.

18
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 15, 2019, 07:20:11 PM »
Looks like Fram export could stall.
..increasing the chances of itp116 making it to the Nares ;)

AWI CS2SMOS merged thickness from .nc using panoply, nov1-12
png files are also available here

19
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: November 14, 2019, 12:40:58 PM »
Suomi NPP VIIRS Brightness Temperature imaging started in Sep2017.
https://go.nasa.gov/2CKFU6A , nov14, 2017-2019. click to run

20
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: November 13, 2019, 02:48:41 PM »
https://go.nasa.gov/2Xd9f3i , yesterday and today

21
Developers Corner / Re: Test space
« on: November 12, 2019, 09:41:20 PM »
Some moving lines but less than I thought. Will take central buoys out till delaunay is stable. The delaunay calculation is before the distance and mesh so the z axis changes shouldn't affect the lines.

Shelving the 3d idea for a while.

22
Arctic sea ice / Re: MOSAiC news
« on: November 12, 2019, 07:01:09 PM »
5 mosaic buoys on iabp have files of incorrect length today, 3 of them were in the group used recently for the deformation test. In particular, 7509680 was a nice outlier to the south east for showing distance change. It's been replaced with 6344810 a little closer in.
This animation updates the one previously upthread using tighter lat/lon and a smaller z axis, day311-316(today). As the ice thickens there is likely to be less movement.

I think some of the movement shown using this method is due to a small distance change causing the delaunay triangulation to connect the buoys in a different order which will give an inaccurate, possibly meaningless, distance change in some of the central points. Using less buoys would reduce that possibility, as would diving deeper into the code. So, probably less buoys ;)
or less animations :)  Removed



23
Arctic sea ice / Re: The caa-greenland mega crack
« on: November 12, 2019, 04:24:31 PM »
More lift off from ellesmere today and quite a big pull back in the Peary channel. Lincoln sea starting to look 'normal'.
https://go.nasa.gov/2KgFdGp , nov8-12 click to run
full moon?

24
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 12, 2019, 01:29:52 PM »
A comparison of nov1-11 from 2016-2019 using uni-hamburg amsr2-uhh. click to run
Late refreeze in Baffin and Foxe Basin this year, also Chukchi.
2016 was late freezing in the Kara sea.
Maybe there is more fresh water refreeze in the Greenland Sea this year?

Wipneus regional extent for Baffin from nov9

25
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 09, 2019, 05:31:34 PM »
Could holes (polinios sp?) in the ice over winter cause extra circulation to draw up warmer water... <snippage>
With air temperatures of -25C the leads (fractures) won't be open water for very long, though the thinner ice does show up warmer using worldview brightness temperature.

The animation below shows uni-hamburg amsr2-uhh ice concentration overlaid onto mercator (model) 0m sea temperature. (amsr2 0% concentration, normally dark blue, has been set to transparent)
oct1-nov8. It looks like a wind driven retreat in the ESS.

edit: Polarview Sentinel 1A of wave action on thin ice near the Chukchi coast today.

26
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 09, 2019, 12:40:28 AM »
When looking at buoys for verification of 'trapped heat' it is nearly always at 25m-75m depth depending on pacific or atlantic side.
13 operational whoi itp buoy data are available here https://www.whoi.edu/page.do?pid=165676

27
Arctic sea ice / Re: MOSAiC news
« on: November 08, 2019, 06:17:46 PM »
One of this morning's sentinel images with mosaic Pbuoy overlay.
This time using the final frame of a very large 2 frame macid animation and using further scaling and rotation to match the sentinel jpg graticule. click to run.

28
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 08, 2019, 01:40:49 PM »
Until the arctic ocean properties change, looking at Wipneus amsr2 regional extent charts, it would appear that there are limits to a late refreeze in the ESS and Laptev (edit: though there might be a retreat in the ESS over the next few days). Kara likely freezing earlier due to the push from the pacific side.
Polarstern temperatures further north perhaps offering some explanation.
Nonetheless, a clearish view of the pole today on worldview suggests that all is not quite rosy and SMB thickness posted here would appear to corroborate.

29
Arctic sea ice / Re: Arctic Image of the Day
« on: November 07, 2019, 11:30:29 PM »
Risto Matilla, an amateur photographer, took this picture of the eggs, the largest of which was the size of a football. Photograph: Risto Mattila
https://www.theguardian.com/world/2019/nov/07/couple-rare-ice-eggs-finnish-beach
Quote
Jouni Vainio, an ice specialist at the Finnish Meteorological Institute, said the occurrence was not common, but could happen about once a year in the right weather conditions.

“You need the right air temperature (below zero, but only a bit), the right water temperature (near freezing point), a shallow and gently sloping sandy beach and calm waves, maybe a light swell,” he said.

“You also need something that acts as the core. The core begins to collect ice around it and the swell moves it along the beach, forward and back. A small ball surface gets wet, freezes and becomes bigger and bigger.”

30
Arctic sea ice / Re: The caa-greenland mega crack
« on: November 07, 2019, 10:56:28 PM »
Ice north west of Ellesmere looking quite ragged today.
https://go.nasa.gov/2CkcoV8 , nov1-7 click to run

31
Arctic sea ice / Re: The caa-greenland mega crack
« on: November 04, 2019, 11:22:56 PM »
Nares export and more lift off from the west greenland coast. Looks set to continue with the current forecast.
https://go.nasa.gov/2rd2Qcm , oct30-nov4, click to run

32
Arctic sea ice / Re: MOSAiC news
« on: November 04, 2019, 09:20:04 PM »
A closer look at whoi itp102
Quote
ITP102 was deployed on a 0.7 m thick ice floe in the Transpolar Drift on October 10, 2019 at 85° 7.9 N, 135° 34.1 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB) and Seasonal ice mass balance buoy were also installed. The ITP includes a second generation prototype MAVS current sensor operating on a pattern profiling schedule including 2 one-way profiles between 7 and 760 m depth each day and SBE-37 microcat fixed at 6 m depth.
The profile contours show small changes down to 50m since the start and the microcat highlights temperature and salinity changes at 6m depth since day300. Here we are also using macid's 3d R analysis to focus on temperature down to 50m showing a small rise of up to 0.16C at ~30m.

A rise in temperature and drop in salinity  at shallow depth could imply some bottom melt but no doubt there are other reasons for these conditions in this area.

33
Very very heavy rain here last night. ;)
Quote
What do I do at this point?
be amazed at the information available at our fingertips :)

34
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: November 03, 2019, 11:45:21 PM »
No chance of blocking now, the ice is not thick and strong, and the "arch" can't freeze deeply into place. This usually happens in Jan-Feb, though Dec is possible too (maybe even Nov?)
Maybe not nov, though it's early days yet

35
Arctic sea ice / Re: MOSAiC news
« on: November 03, 2019, 09:58:30 PM »
A longer timescale view of the mosaic buoy network building up, day275-307 (today), no projection.
Dropouts (buoy fails to report or report is not recorded) show clearly using delaunay.  A large number of buoys close to PS dropped out on day304.

36
Arctic sea ice / Re: The caa-greenland mega crack
« on: November 03, 2019, 03:08:41 PM »
uni-hamburg amsr2-uhh, north CAA/Greenland, 2012-2018 (some missing data)

37
Arctic sea ice / Re: The caa-greenland mega crack
« on: November 02, 2019, 08:48:39 PM »
Floes tearing across the PGAS, recently fast ice lifting off from Ellesmere.
https://go.nasa.gov/32a0hoj, oct31-nov2   click to run

38
Arctic sea ice / Re: The 2019/2020 freezing season
« on: November 01, 2019, 10:18:40 PM »
Ascat A,B,C A,C,B day233-303. Some weather interference ;)

39
Arctic sea ice / Re: MOSAiC news
« on: November 01, 2019, 09:02:11 PM »
Ascat now provides 3 images/day giving the opportunity for finer analysis of movement, though the image times (unknown) don't appear to be evenly spread.
Here we are looking at the interferometry method described here which highlights areas that move more than others with brighter colours, those moving less tend towards grey.
The rough position of polarstern can be estimated from the ice edge and SZ, top right.
day292-301


40
Arctic sea ice / Re: The caa-greenland mega crack
« on: October 31, 2019, 08:42:21 PM »
Today's worldview viirs brightness temperature band15, night. 'Heat' escaping from the cracks at ~-2C. Cloud forming over the Lincoln sea at some distance from the Greenland coast. Click for full resolution.
https://go.nasa.gov/2WvntvO

41
Arctic sea ice / Re: The caa-greenland mega crack
« on: October 31, 2019, 04:40:30 PM »
uni-hamburg amsr2-uhh update of the caa/cab crack, sep21-oct30

42
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 30, 2019, 12:20:50 PM »
Mercator temperature 0m, sep21-oct29 with uni-hamburg amsr2-uhh overlay at 60% transparent. (0% concentration fully transparent)
Mercator would appear to be struggling to model the rapid refreeze. click to run
The Mackenzie bay area is interesting. amsr2 indicating rapid refreeze and melt. Worldview image of oct27. Unfortunately it has been cloudy since then

43
Arctic sea ice / Re: MOSAiC news
« on: October 25, 2019, 04:52:25 PM »
I had to increase the distance scale on the deformation test from 0.001km to 0.0016 to avoid clipping the lower points on yesterday's buoy data. That's compression so perhaps those leads have a bit more ridging now. It doesn't look like a smooth ride but this software presentation needs some verification from a ground report.
If you have a wider angle version of the gif above a bouy overlay with some distances might be one way of verifying. (Post temporarily if very large?)
tech note: 2 buoys had dropouts so only 30buoys in this ani. Good day for gardening so no coding today.

44
Arctic sea ice / Re: MOSAiC news
« on: October 24, 2019, 11:38:26 PM »
Been asleep at the wheel, whoi itp102
Last position on 2019/10/24 180047 UTC : 85.6311° N, 128.4221° E
edit: Drift will be similar to other buoys, added temperature and salinity 7-250m. (click to run) Much higher salinity at ~32.4 than we've become accustomed to seeing from the whoi buoys in the Beaufort.
Note that the temperature doesn't increase till ~75m depth

Thickness at 85.79N only 0.7m. IMB at same location

Quote
ITP102 was deployed on a 0.7 m thick ice floe in the Transpolar Drift on October 10, 2019 at 85° 7.9 N, 135° 34.1 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB) and Seasonal ice mass balance buoy were also installed. The ITP includes a second generation prototype MAVS current sensor operating on a pattern profiling schedule including 2 one-way profiles between 7 and 760 m depth each day and SBE-37 microcat fixed at 6 m depth.

Quote
ITP111 was deployed on a 2.8 m thick ice floe in the Transpolar Drift on October 5, 2019 at 85° 1.8 N, 132° 44.5 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB), a Seasonal ice mass balance buoy, a Meteorological sled, Spectral radiometer and AWI snow buoy were also installed. The ITP is operating on a standard sampling schedule of 2 one-way profiles between 7 and 760 m depth each day.
Will look at itp111 in a few days. 2.8m thick :)
Last position on 2019/10/24 60101 UTC : 85.3098° N, 128.2632° E

45
Arctic sea ice / Re: MOSAiC news
« on: October 24, 2019, 10:34:54 PM »
Deformation test suggesting there is still significant movement up to 7am this morning. A few buoys reported till 10am but not really enough to run a separate subset. There are 32 in this animation.
The iabp page updates a few times a day(not sure of the exact times yet), the mosaic buoy data less often.

46
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 24, 2019, 09:16:27 PM »
Probably best to use SST rather than anomalies, they only add another layer of complexity to think about. They look (and are) more dramatic though.

47
Developers Corner / Re: Test space
« on: October 22, 2019, 12:01:16 AM »
delaunay test showing 35 iabp mosaic buoys, naybe some are in similar locations. That will show up with labelling. This only shows 0mins, not the 30m. Quite a few dropouts. Will have to think about how to handle those.
added mp4 which includes the recent distortion.
removed

48
Arctic sea ice / Re: MOSAiC news
« on: October 20, 2019, 10:32:50 PM »
Fortunately the sailwx shipdump is in decimal degrees or I'd have to run that ani again.
https://www.sailwx.info/shiptrack/shipdump.phtml?call=DBLK

They've also reserved 6 decimal places but PS only uses 1 ;)
"UTC date/time","Unix UTC timestamp","lat","lon","callsign",
"2019-Oct-20 1900", 1571598000, 85.000000, 132.800000, DBLK,

Quote
The difference between N 85°00' and N 85°01' is 1/60 of 111111 m or 1850 m. The difference between E 132°42' and E 132°43' (at 85º.00') is (haversine) 161.5 m but at 84º it is 193.7 m.
Perhaps the deformation presentation would be better shown in km.

added a crop of the mosaic no overlay map, oct11-19. click to run.

49
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 18, 2019, 10:57:00 PM »
whoi-itp103 unsure where to go again at the mouth of the amundsen gulf. Another temperature spike at 6 and 7m, salinity also higher this time with less melt above.
https://www.whoi.edu/page.do?pid=163356

50
Arctic sea ice / Re: MOSAiC news
« on: October 18, 2019, 09:54:16 PM »
Back to the buoys. Here are the drift/delivery paths of 64 iabp buoys near the Mosaic area. There are 3 more, I think, with short identifiers and a slightly different format, not shown. Some have occasional -ve entries. At some point the id number should be related to buoy type.
Current list is attached as txt file.
added meerisportal list.

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