Support the Arctic Sea Ice Forum and Blog

Author Topic: MOSAiC news  (Read 95254 times)

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #550 on: January 30, 2020, 02:48:44 PM »
drift update, pretty much due east again after 2 hairpin bends. Here introducing p193, making a grand entrance by obliterating the 87.4N label but should improve efforts at estimating PS location. P201 can take a well earned rest.
edit: updated to jan31 02:14, headed south temporarily.
edit2: T56 temperatures (every 6 hours) over the same time period (jan18-31), confirming the FoMo temps below.

The nearest Obuoy, 2019O4, with surface temp measurements every 10mins must have the sensor buried in snow/ice
« Last Edit: January 31, 2020, 09:25:53 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #551 on: January 31, 2020, 11:42:50 AM »
Quote
after 2 hairpin bends
The Polarstern enters the maelstrom later today; it may seriously contort tracks of the buoy array that accompanies it by midnight UTC. The bottom slideshow below scales the maximum view of GFS at Nullschool up 22.23x to match the scale of Uniq's buoy tracks. They are positioned very differently with respect to cyclone wind speed which increases drastically out radially (from 2 to 12 m/s). The position of the Polarstern is uncertain 12 hrs out, as is GFS.

Some km-scale shifts in the ice off the Polarstern's bow and port sides accompanied the twenty hour episode of double digit winds on Jan 30th. The white scale bar should be 250m not 25.

While waiting around for the KD to leave for leg 3, L Kaleschke made quite an interesting whole-Arctic mp4 of leads from "AMSR" from Oct 1st to Jan 31, archived as small individual grayscale tifs. The whole current set of 123 days open up to a reasonable 78 MB. This is a very important addition to the overly local (5 km) view of leads from the bridge radar.

Note this cannot be done from the AMSR2 png archive we use because in mid-winter even the large format images are almost entirely pure white, 255 (100% SIC). There's no information about leads in a block of pure color. Kaleschke's tifs use very light grayscale but only the pole hole is white.

The indexed coloring scheme resolution seems sub-optimal but alternatives are easy with ImageJ. The Polarstern track could be added though it is tiny at this scale; S1AB thumbnails and bow radar could be inset in wasted space. The leads could be extracted and overlaid on Ascat with 'darken only'. For that, all the leads, thick or thin, need to be pulled with 'threshold'.

ftp://ftp.awi.de/incoming/lkalesch/MOSAIC/  no password needed
https://twitter.com/seaice_de/status/1221805753050320896
« Last Edit: January 31, 2020, 06:39:53 PM by A-Team »

Florifulgurator

  • Frazil ice
  • Posts: 285
  • Virtual world alter ego / अवतार of Martin Gisser
    • View Profile
  • Liked: 135
  • Likes Given: 85
Re: MOSAiC news
« Reply #552 on: January 31, 2020, 01:17:09 PM »
ImageJ
Sorry for OT, but... image processing in Java?  Does this thing really work?

It's been some time ago, when I had to program and/or use Java for graphics. Some of the most ridiculous (incl. dangerous) bugs/algorithms I've ever seen. Not to speak of the performance.
Google image search on my avatar image gives "wood". In fact it is the lower part of David Hilbert's tombstone.

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #553 on: January 31, 2020, 01:37:47 PM »
Quote
image processing in Java?
Yes, ImageJ freeware was built by and for scientists doing advanced imaging analysis in cell biology and astronomy. It is extremely stable and fast with a large tool overlap with Photoshop and Gimp but many powerful ones of its own. It has a common code base with great updating but grows by independent contributed modules (.jars) that don't trip over each other as you add them. Most of these are implemented algos from mathematics-based IP journals. It is very convenient for complex manipulations of stacks (ie time series). One weakness is very limited 'undo'; another is alpha channel masking.

C Katlein, the ROV operator on leg 2, has been posting interesting photos almost every day (despite FoMo publicists repeatedly insisting the Polarstern's 100 mbps internet connection doesn't allow for this.) 

https://twitter.com/CKatlein

Other people are tweeting about bear visits; these have been far more frequent than FoMo has acknowledged. These are not always seen by the bear guards; some visits alongside the ship are inferred from tracks. Both polar bears and foxes associate ships with food; people on the AF even fed them over the rails. 

The first image below shows the view from below: the ROV mapping the depths of pressure ridge keels. Only the z axis is provided so the xy scale relative to the Ice Camp and the five ridges being drilled isn't provided but probably is 500 m or so. Some of the keels go quite deep, perhaps 5 m; it's hard to say as palette colors don't match depth colors.

The ROV is also pictured measuring an ablation stake sticking out the bottom of the icepack. Ice, especially on keels, is lost frictionally from drift relative to stationary ocean water; deeper keels melt because they're situated in water above the freezing point. The sub-freeboard ice pictured is 0.9 m.

FoMo is reporting extreme bounces in ship weather today that are in mild contradiction to the weather data they send out to awiMet, sailwx, DWD (Germany's NWS), and ECMWF. This might result from using instantaneous data vs hourly means or from stations at different heights above the ice.

Oddly, Mosaic does not seem aware of GFS nullschool providing frequently re-initialized and so far quite accurate 3-hour views of wind direction and strength forming the basin-wide cyclonic weather pattern, despite having a full-time staffer on board from Deutscher Wetterdienst. All the comments to date take a purely point perspective whereas a synoptic view is essential to understanding where the warm and cold air are coming from, why the ice is fracturing and where the Polarstern will drift next.

Attached also is an edited list of 56 recent papers by leg 2 leader C Haas. His background is geophysics and main current interest observation-based sea ice thickness. Free full texts are easily located online by searching on the full titles; he also maintains a ResearchGate page. His most recent paper, moored sonars in the Laptev, has just gone into review at open source/open review Cryosphere Today (where he is an editor!).

Compare this statement from Haas to the data hoarding during leg 1:

Quote
One of the objectives of the CryoVEx campaign was to observe how snow and sea-ice thickness varies along a CryoSat track from the coast of Canada across the multiyear ice zone into the first-year ice further north.

A week after this part of the CryoVEx campaign was completed, data processing has progressed and we can present some first results. These will be invaluable for CryoSat and IceBridge data processing by the various groups, for assessment of the state of Arctic sea ice after an exceptionally warm winter, and for initializing predictions of summer ice conditions.

https://www.the-cryosphere-discuss.net/tc-2019-307/
http://blogs.esa.int/campaignearth/2017/05/01/cryovex-first-results-show-sea-ice-continues-to-thin/
« Last Edit: January 31, 2020, 06:35:35 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #554 on: January 31, 2020, 08:55:31 PM »
I dug out the old delaunay test program written using octave for an overview of buoy drift from 66 iabp buoys, jan1-31
No projection. - removed
Projected version below
« Last Edit: February 02, 2020, 05:38:29 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #555 on: February 01, 2020, 01:21:10 PM »
Very nice amsr2 arctic lead product.
Some Pbuoy data yesterday was every 3 hours instead of 30mins.
2020-01-31T00:00:33,87.4500,95.7151,0.012,NaN,0.0,3.0,1800.0
2020-01-31T03:00:33,87.4516,95.7237,0.017,NaN,0.0,3.0,1800.0
2020-01-31T06:01:08,87.4552,95.7420,0.039,NaN,0.0,4.0,1800.0
2020-01-31T09:01:05,87.4651,95.7013,0.103,NaN,0.0,4.0,1800.0
2020-01-31T12:01:05,87.4851,95.5790,0.215,NaN,0.0,3.0,1800.0
2020-01-31T15:00:36,87.4989,95.5017,0.147,NaN,0.0,7.0,1800.0
2020-01-31T18:02:07,87.5078,95.5309,0.092,NaN,0.0,11.0,1800.0
2020-01-31T21:01:04,87.5147,95.5807,0.076,NaN,0.0,6.0,1800.0
2020-02-01T00:00:54,87.5176,95.6063,0.032,NaN,0.0,4.0,1800.0

Only showing 204 and 207 as there are some other odd data on p193 and p201
updated below
« Last Edit: February 02, 2020, 11:17:23 AM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #556 on: February 01, 2020, 03:45:52 PM »
As a tightly wound cyclone drifted over the Polarstern this morning, near-surface conditions went from 1 m/s under the eye to 16 m/s in single hour accompanied by a 180º shift in wind direction, then reached an expedition peak of sustained 19-20 m/s winds. (In other units, 20 m/s is 77 km/hr, 38.9 knots, 44.7 m/h).

Note the extraordinarily warm near-surface air temperatures in the early am: -11.5ºC. GFS has this at 11.0ºC. FoMo goes on with crazy talk about this warmth coming up from Svalbard despite the wind there blowing straight down the Fram. FoMo ignores the storm raging outside to share more trivia on microscopic plankton and cod minnows.

Better to have saved the life boat story for today? Some 90% of ship emergencies are due to fires on board. The captain has discussed the many preparations for that. Despite off-loading gear to the ice, many tons of untested electrical devices from 19 countries remain aboard.

Should the ship list seriously to port because of impinging starboard pressure ridge ice (on the Fram, these got higher than the mast), it won't be possible to launch half the lifeboats using eight guys tugging on a rope around a dislodged mooring I-beam. The other lifeboats might launch adrift in a corresponding port lead and so be inaccessible. Would it make sense to store some well-stocked lifeboats on the ice the whole time?

Without the Pistenbullys, an emergency airstrip could not be groomed. Indeed, we've not seen the promised follow-up on the trial airstrip of Jan 8th. It must have become totally inoperative within days from the daily ice pack grinding seen on bow radar; it would take an amphibious 4WD ATV to go down the runway now. This scenario could leave 150 people doubled up on half rations inside the functioning lifeboats for a month or more.

Quote
2020 AWI is recruiting 17 PhD candidates and 12 Postdocs to strengthen its new research program "Changing Earth – Sustaining our Future". Applications ar now open in the following research areas: atmosphere, ocean, ice and land; Arctic ecosystems and permafrost, marine and polar life marine bio-economy. Over €1 000 000 000 has been allocated to build Polarstern II.
How about €50/day to pay a science grad to oversee daily FoMo blurbing? Climate change --> no fisheries bio-economy in the Arctic or anywhere else after the ice melts, why throw resources at it.

The sharp curvature and high (and rapidly changing) gradient of the wind stress field will couple strongly to edges of pressure ridge jumbles and giant sails like the Polarstern side. The ship's orientation (bearing) is not disclosed so we don't know when the winds hit broadside or astern; there's no S1AB coverage today.

Pitch and roll are not disclosed either, though even the min-sub has a nice heads-up display of them. We can see from swings in the bow radar contrast and orientation that the ship is not really frozen-in but merely moored on the starboard side.

This is by design as the hull must lift up (rather than collapse) if pressured by ice on the side. The draft as currently loaded is ~4.0m so most of submerged parts (eg keel and propeller) lie in water too warm too freeze. An early FoMo photo out from the moon pool confirms this.

These high wind speeds will put record stress on the icepack. However today's bow radar will only cover the fracturing until midnight of Jan 31st; the event is continuing through 1500Z today. The drift is strongly to the Siberian south and slightly west ('to the right' of GFS wind as Nansen noted).

In the awiMET table, when their one decimal latitude and longitude "hold steady" despite sustained strong winds from 330º, that means the Polarstern is rapidly moving due south towards the New Siberian Islands. This will eventually show up as 87.3 latitude. (The Polarstern drifts about 7 km/day, 0.29 km/hr on Uniq buoy scale, under local winds speed averaging 6 m/s or 22.6 km/hr.)

Only minor plate readjustments on the port side have occurred so far, raising the question of time lag between applied stress and brittle failure. However a 4.2º CCW rotation of the bow took place in the 12 hours before midnight on Jan 31.

  87.4  95.9 20-02-01 18:00  08  330   -38.2 1000.7  third radar frame tomorrow
  87.4  95.8 20-02-01 17:00  09  330   -37.8 1000.1
  87.4  95.8 20-02-01 16:00  11  330   -37.6  998.9
  87.4  95.7 20-02-01 15:00  11  320   -37.1  998.1
  87.4  95.7 20-02-01 14:00  11  320  -36.2   997.1
  87.4  95.7 20-02-01 13:00  12  330  -35.4   995.6
  87.4  95.7 20-02-01 12:00  13  330  -34.7   994.4  second radar frame tomorrow
  87.4  95.7 20-02-01 11:00  15  330  -33.9   992.6
  87.4  95.8 20-02-01 10:00  16  330  -33.2   990.9
  87.4  95.9 20-02-01 09:00  16  340  -32.8   989.1
  87.4  96.0 20-02-01 08:00  18  340  -31.6   987.3
  87.4  96.1 20-02-01 07:00  19  350  -30.9   985.0
  87.5  96.2 20-02-01 06:00  19  350  -29.0   982.7  first bow radar frame tomorrow
  87.5  96.2 20-02-01 05:00  20  360  -27.6   979.8
  87.5  96.3 20-02-01 04:00  19  360  -25.7   977.3
  87.5  96.4 20-02-01 03:00  16  010  -21.6   975.2
  87.5  96.4 20-02-01 02:00  01  300  -11.5   974.6  gap of one hour
  87.5  96.4 20-02-01 00:00  07  190  -12.0   976.4  last bow radar frame today
Quote
Very nice amsr2 arctic lead product.
Very nice indeed! Kaleschke has been publishing on AMSR-E (passive 18.7, 89 GHz, since 2002) for 13 years including lead detection so this is not out of the blue -- but what sudden inspiration struck him there on the wharf? Hopefully updates will keep coming while at sea; posting time changes suggest a pipeline is not yet fully set up.

This will get us into Hough transforms, a familiar technique from image analysis used to detect sub-pixel geometric features such as linear leads. ImageJ plugins are totally on top of this.

Hough was automating bubble chamber decay analysis in the 1950's. In math, these have been known as 2D radon transforms from 1917 on. The inverse is used in medical scans.

In the case of leads, a time-dependent 2D+T Hough transform might sharpen the product. That is, OsiSaf describes basin-wide how ice is moving, meaning the day n+1 AMSRE can be brought back to augment the search of leads on day n. (For all we know, this could have been Kaleschke's processing breakthrough.)

Regionally, ice motion is available from consecutive S1AB pair overlaps which generally exist for the Polarstern area. Locally, the buoy swarm gives ice motion very accurately at 30 minute intervals; leads can be extracted from dispersion in the delaunay diagram (the GPS is precise, ice does not stretch). However the scale of buoy deployment is well below that of AMSRE.

Pressure ridges don't show up on that satellite but can be inferred to exist when a lead closes, provided that can be distinguished from freezing over. Tracking these features might identify multiple openings over time of the same weakness.

The Feb 1st lead frame is below, slightly modified. Note how the view is cut off well east of Banks Island and much of the Beaufort/Chukchi; the detectable leads detected are almost entirely in MYI.

The base map is the same projection but different scale as forum AMRS2. However that can provide convenient land and open water masks and a graticule at 124.98% enlargement. Note the pole hole is slightly larger in AMSRE-K but still well inside 89º. Ascat then needs to be resized by 2.2827 * 1.2498 = 2.8592 to take a dark or colored overlay from what we think is AMSRE-Kaleschke.

However even if the latter is cropped to the 'good stuff', it is still 770 pxls wide, whereas the forum limit is 700 so the above enlargements need to be dialed back by 10%. Assuming only MYI is left at the time of mooring on Oct 4th, it may make sense to use the AMSR2 open water to mask AMSRE-Kaleschke on all the latter dates since the leads (and Polarstern) are in the MYI and drift within the frame.

On the bright side, the 90º Eurasian quadrant of the Polarstern provides 350x350 pixels of AMSRE-K lead resolution, meaning it probably can withstand 2x enlargement or double up as is with 3 other resources as a 700x700 (alt 4:3 or 16:9 aspect) mp4.

Care must be taken with repeatability of crop boundaries, enlargements and contrast enhancements so that incoming Feb updates to the leads can be easily concatenated onto the current product.

Sea ice leads in the Arctic Ocean: Model assessment, interannual variability and trends
Q Wang, S Danilov, T Jung, L Kaleschke… - Geophysical …, 2016

Wernecke, A.; Kaleschke, L. . “Lead detection in Arctic sea ice from CryoSat-2: quality assessment, lead area fraction and width distribution”. The Cryosphere 9. (2015): S. 1955-1968.doi:10.5194/tc-9-1955-2015

Röhrs, J.; Kaleschke, L.. “An algorithm to detect sea ice leads by using AMSR-E passive microwave imagery”. The Cryosphere 6 (2). (2012): S. 343-352.doi:10.5194/tc-6-343-2012

Röhrs, J.; Kaleschke, L.; Bröhan, D.; Siligam, P.K.. “Corrigendum to "An algorithm to detect sea ice leads by using AMSR-E passive microwave imagery" published in The Cryosphere, 6, 343–352, 2012 ”. The Cryosphere 6 (2). (2012): S. 365-365.doi:10.5194/tc-6-365-2012

Gunnar Spreen, Lars Kaleschke, Georg Heygster, "Sea ice remote sensing using AMSR-E 89-GHz channels", Journal of Geophysical Research, vol. 113, 2008.
« Last Edit: February 02, 2020, 12:12:13 AM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #557 on: February 02, 2020, 11:21:28 AM »
Some rapid drift south yesterday. PS has spent over 16days in this area.
300 frames @ 12fps (increased from the usual 7fps)
updated below

A nice job for someone to verify those leads at some point.
https://go.nasa.gov/3924uhG, feb02, rough mosaic area circled cffr
« Last Edit: February 03, 2020, 01:42:52 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #558 on: February 02, 2020, 04:03:22 PM »
Quote
Some rapid drift south yesterday. PS has spent over 16 days in this area. Verify those leads!
It may not work that well to compare infrared (heat leaks) to radar (salinity, SIC). Leads freeze over within hours at the prevailing winter temperatures; that will affect the two images differently. The infrared image has much better resolution during cloud-free days.

A lot can be done with this AMSRE time series from L Kaleschke, including visualization of whole icepack drift about as well as Ascat. Both suffer somewhat from incoming weather systems.

The major cyclone is affecting the ice around the Polarstern at quite a few locations but so far not as severely as the Nov 19th storm. That didn't really give rise to major chaos until the 22nd.

On the bow radar, the Polarstern at 118 m in length scales to just 12 pixels in length. A few multiples of that radius would pick up most of the instrument sites, the test runway, CTD and ROV  holes and other observation sites. The 3x enlargement is about all the image quality allows after enhancement. Almost all of the starboard side gets masked out in the archive for unknown reasons (the radars can provide 360º coverage as seen in N-ICE2015 data).
« Last Edit: February 03, 2020, 03:24:31 AM by A-Team »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #559 on: February 02, 2020, 04:43:43 PM »
A late S1AB surfaced for 06:02 on Jan 31st. The PS is at 87.4365 96.4841 on that image; the floe is quite altered in appearance. Some rifts are nearby that may have absorbed some of the wind stress.

The Polarstern (red asterisk) barely made it onto Sentinel coverage. The image is rotated 180º from PolarView to correspond better with Mosaic orientation. The blue arrow runs along the ship axis with starboard and port sides indicated. The bow radar points along this axis but is imaged as vertical. An extended rift (yellow arrows) possibly corresponds to a local shear line seen active above. The exit track of the KD is still visible as a white streak.

The second image is a composite of two consecutive Sentinel orbital scenes derived from the jp2 rather than the jpg. The blue ellipse shows a rift zone a ways from the Polarstern. This rift is difficult to date because coverage by Sentinel has been spotty with the ship dodging in and out of the pole hole in recent weeks.

Another S1AB just surfaced, for 02 Feb 2020. A remarkable rotation and translational drift of the Polarstern region took place during these 48 hours.
« Last Edit: February 03, 2020, 12:12:03 AM by A-Team »

blumenkraft

  • Young ice
  • Posts: 4402
  • Fans of Hans Ø Club - circa 2018
    • View Profile
  • Liked: 1502
  • Likes Given: 2328
Re: MOSAiC news
« Reply #560 on: February 03, 2020, 07:06:49 AM »
The IcePod

at www.polarprediction.net

Quote
The IcePod is the podcast about polar science and the people. We’ll talk to scientists who went on board Polarstern, the German research icebreaker, for the biggest research expedition in the Arctic. The IcePod is the official podcast of the YOPP

Link >> https://overcast.fm/itunes1480223567/the-icepod
“I’m an introvert. I’m just different that’s all. I’m so sorry. I don’t have a gun. I don’t do that stuff... All I was trying to do was to become better. I’ll do it... You all are phenomenal. You are beautiful. And I love you. Try to forgive me. I’m sorry.”

Elijah McClain

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #561 on: February 03, 2020, 01:47:05 PM »
drifted north west yesterday, arriving very close to last week's location
300 frames@12fps

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #562 on: February 03, 2020, 04:44:37 PM »
Quote
arriving very close to last week's location
Very effective visually to have tracks speed up as the drift speeds up. The km/hr scale has tripled to accommodate actual data (next post); scales are not the same in different buoy animations. Km/hr is the appropriate unit here; it's hard to picture a floe moving even one meter per second (SI extremism?). For glaciers, m/d makes more sense (Jakobshavn got up to 51 m/d).

The question is, do the buoys show this behavior every year but we just don't notice because their motion is commonly dumbed down to weekly resolution? I would say no, the wind pattern has been very peculiar this year -- and that's about to continue with strong poleward motion turning east.

Been there, done that, doing it again:

  87.4   94.0 20-02-03 18:00
     87.4   93.9 20-02-03 17:00
         87.4   93.8 20-02-03 16:00
             87.4   93.7 20-02-03 14:00
                87.4   93.6 20-02-03 13:00
                   87.4   93.5 20-02-03 12:00
                      87.4   93.3 20-02-03 10:00
                          87.4   93.2 20-02-03 08:00
                          87.4   93.2 20-02-03 05:00
                      87.4   93.3 20-02-03 03:00
                   87.4   93.5 20-02-03 01:00
                 87.4   93.6 20-02-03 00:00
             87.4   93.7 20-02-02 23:00
         87.4   93.8 20-02-02 22:00
     87.4   93.9 20-02-02 21:00
  87.4   94.0 20-02-02 20:00

The lead openings and closings are very active on a day by day basis though not much of that shows up on the Polarstern bow radar. The new scale bars are multiples of the 118m ship's length as almost all activity is nearby.

The Polarstern was in range this morning for a 06:00 Sentinel at 87.4 93.2. PolarView is just now back from its near-daily breakdown; nothing north of 86.9 is showing.
« Last Edit: February 03, 2020, 08:43:46 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #563 on: February 03, 2020, 08:28:50 PM »
The km/hr scale has tripled (or typo)?
The scale is auto calculated by R. 0.481m/s(1.73km/hr) is pretty quick. Extract from P193 below.
2020-02-01T06:30:25,87.4429,98.2130,0.467,NaN,0.0,3.0,1800.0
2020-02-01T07:00:30,87.4355,98.1605,0.481,NaN,0.0,4.0,1800.0
2020-02-01T07:30:27,87.4283,98.1003,0.478,NaN,0.0,3.0,1800.0
2020-02-01T08:00:28,87.4213,98.0384,0.463,NaN,0.0,4.0,1800.0
2020-02-01T08:30:35,87.4148,97.9766,0.438,NaN,0.0,6.0,1800.0

I don't think that there are many previous buoys to compare to in this area. Perhaps someone will search a couple out. Drift may appear faster when hourly reports are missing, for example on jan31

Here showing most mosaic iabp buoys that report on the hour from sep29 to feb2. R was used to calculate utm lat and lon and the graticule as in the drift animations. The data was then run in octave to present the delaunay triangulation. A small mismatch in image size required rescaling of the  graticule so this is best efforts and should be seen as a guide only.
edit: The longitude labels are incorrect, they should be one place to the left. 135E is vertical.
« Last Edit: February 04, 2020, 10:56:43 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #564 on: February 03, 2020, 09:25:37 PM »
Quote
Drift may appear faster when hourly reports are missing
Slower? If the drift is A --> B  --> C  and the hourly is missing for position B, then the A --> C speed will be slower to the extent ABC are not co-linear (triangle inequality).

FoMo gave a dramatic example of this on Jan 14th (while omitting the key parameter, sampling interval). At a buoy track crossing, the difference in position (distance covered) is zero as is the speed but not the elapsed time.

The triangle inequality also holds on the surface of a sphere (or any Riemannian manifold) but lines have to be geodesics. The buoys are not constrained to move on geodesics (which become complicated in a hurry on the WGS ellipsoid).

Distances between two lat lon points are typically approximated with the sphere's haversine even if that geodesic doesn't follow along the actual buoy track. When the points are close (ten minute sample times, slow speeds, no jogs), the difference is utterly negligible and in fact ordinary lines on the euclidean tangent plane suffice.

The issue here is not the ice speed per se but how it got there, what keeps it there and what alters direction. In a situation like the central Arctic with negligible near-surface currents and tidal influences, this is mainly wind pushing on ridges but retarded by keels and drag with sea water.

Because of friction, there's no conservation of momentum: a floe in motion doesn't stay in motion. Kinetic energy is quickly being dissipated as (unnoticeable) heat.

Is there is such a thing as terminal velocity for ice (as for skydivers) and have we approached it during the Mosaic expedition. Yes, wind can't keep up with subsurface drag which goes up like the cube. No, because the 10-12 storms expected haven't happened; extreme winds so far have been south of Svalbard and east in the Barents.
« Last Edit: February 04, 2020, 01:48:42 AM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #565 on: February 04, 2020, 11:57:35 AM »
The art of moving without moving.
Here breaking out best time detail with 715 frames at 24fps.

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #566 on: February 04, 2020, 01:08:29 PM »
Quote
art of moving without moving
Art of back and forth on Feb 4th: The three bow radar scenes are best processed individually because of contrast variability extremes within the master frames. They are all from the same date, Feb 3rd. Some of the leads, shears and ridging may extend into the Mosaic ice camp experimental areas or impinge on the planned port side airstrip.

The new archive of Arctic-wide leads extracted daily from AMSR-E by L Kaleschke are shown with exaggerated contrast under land and graticule masks from AMSR2. The red star at 87.5 95.0 shows the approximate position of the Polarstern.

It is not currently possible to definitively relate new leads seen on the basin-wide scale with much smaller features that can be seen at bow radar resolution.

T Lavergne's OsiSaf shows ice motion at a similar scale as AMSR-E. The two aren't readily compared because OsiSaf needs two days of data to get one picture of motion; further the data is gridded meaning the features used in AI are not retained or displayed.

T Krumpen is on different legs of the Polarstern (1a AF + leg 4 vs leg 3) than Kaleschke but both work at AWI so it reasonable to expect sea ice motion products to be improved soon. (Not in summer though.)

No S1AB today. The Polarstern will soon be in its pole hole again (but not that of AMSRE leads), followed by a full day of Fram-ward drift, followed by becalmed. What might be called aTPD (accidental Transpolar Drift).

87.5   95.3 20-02-04 14:00    8  180    -27.4

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2020&month=02&day=03&action=Today&prod=LR-Drift&area=NH&size=100%25

https://www.the-cryosphere.net/13/3261/2019/ latest SIC review of over-estimates
« Last Edit: February 04, 2020, 05:11:58 PM by A-Team »

gandul

  • Frazil ice
  • Posts: 426
    • View Profile
  • Liked: 126
  • Likes Given: 7
Re: MOSAiC news
« Reply #567 on: February 04, 2020, 06:08:12 PM »
I wonder if the Polarstern could be crushed if it gets close to Fram before Summer, as ice streamlines converge laterally as the ice accelerates (in the average motion), it is like people wanting to pass a small door in a panic situation. Would that be a real concern or the boat  should resist?

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #568 on: February 04, 2020, 08:52:04 PM »
The Polarstern has been on the job for 39 years. Its hull is designed to lift up when experiencing compressive forces from the sides. It's not clear what happens if the ship is torqued by forces at shearing angles. It has strain gauges welded on the lower hull but when frozen in, options are limited. Would the ship roll on its side or suffer structural damage?

In olden days, ships had  stout oak beams running abeam, seemingly crushproof. That design didn't end well for the Jeanette: 

On 7 Sep 1879, the ship became frozen in the ice at 71°N 175°E. For the next 21 months, Jeannette drifted in an erratic fashion, frequently doubling back on herself. On 12 June of 1881, the pressure of the ice crushed the Jeannette. De Long and his men unloaded provisions onto the ice and watched as the ship sank at 77°N 155°E [well south and east of the Polarstern).

Wreckage eventually came ashore on the central east coast of Greenland where it was discovered by Nansen on a field trip there. This inspired his theory idea of Transpolar Drift. It is evidence, along with carbon-dated beached logs at Morris Jesup, that the TPD (and Fram export) have been operative a very long time, even when the ice was much thicker and extensive than today.

Note the distinction: Transpolar Drift refers to surface ice blown by the wind; Fram export is return flow of Atlantic Water inflows that are ~300 m below the surface. The two often work together at the intake funnel of the Fram Strait at ~82º (East Greenland Current). Mosaic is tracking this double-diffusing Atlantic Water and its turbulent eddies at depth for the entire expedition.

However it's not immediately apparent from the buoy array tracks that the cw TPD -- which is air pressure pattern-dependent and ultimately driven by ccw earth rotation -- is operative this year.

The Beaufort Gyre, the other textbook staple, is still going around and around in the minds of True Believers despite irrefutable satellite evidence to the contrary. A Beaufort arm of floes derived from MYI ice off the CAA reaches up the AK coast to the Chukchi in most years but never completes a gyre. Today Beaufort winds are circulating in a nice gyre but in the wrong direction!
« Last Edit: February 04, 2020, 09:13:30 PM by A-Team »

blumenkraft

  • Young ice
  • Posts: 4402
  • Fans of Hans Ø Club - circa 2018
    • View Profile
  • Liked: 1502
  • Likes Given: 2328
Re: MOSAiC news
« Reply #569 on: February 05, 2020, 09:29:05 AM »
“I’m an introvert. I’m just different that’s all. I’m so sorry. I don’t have a gun. I don’t do that stuff... All I was trying to do was to become better. I’ll do it... You all are phenomenal. You are beautiful. And I love you. Try to forgive me. I’m sorry.”

Elijah McClain

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #570 on: February 05, 2020, 01:53:22 PM »
Quote
photo credit: Lukas Piotrowski
Here are 127 days of Ascat and AMSRE leads from Oct 1st to today. The Polarstern is currently about a third of the way from the pole to Severnaya Zemlya (87.5 95.0 20-02-05 09:00). It is feasible to overlay the leads and still see how the MYI ice on Ascat is drifting. Note the multiple origins of ice exiting the Fram.

The overlay of sea ice concentration derived leads on cry2smos derived thickness works well though thickness doesn't change much over the mid-Oct early-Feb time span. (Note only 103 days are available compared to 127 for Ascat and SIC leads because of a delayed start to cry2smos and delayed archiving necessity.) This new product AMSRE lead archive from L Kaleschke has enabled some important new visualizations.

No action today on the bow radar and none expected for the next few days as the ship drifts farther north and then east. The Polarstern will be within the pole hole of S1AB so no images will be available.

It would be instructive to make a one-day three-way comparison of infrared (#557 250m VIIRS brightness temperature, band I5 night), SIC leads and S1B. It is a little trickier to synchronize an overlay 24-hour leads on GFS nullschool winds which is 3-hour without file size getting out of hand.
« Last Edit: February 05, 2020, 05:21:08 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #571 on: February 06, 2020, 01:44:39 AM »
Nice aspect ratio for wide screen. Some leads persist for a long time as lower concentration blobs.

Not many buoy 'proc' files were updated today. There are other unprocessed files providing latlon that we can use. Example from p201
DataId,CommId,DeviceName,DeviceDateTime,BatteryVoltage,GpsQuality,Latitude,Longitude,SubmergedBoolean,Temperature0cm,AccelerometerVariance,SamplingRate
24309464,"300234068912800","OSU-IT-0014",2020-02-05 21:00:25,10.5,3,87.524023,94.845873,0,,3,30
24309463,"300234068912800","OSU-IT-0014",2020-02-05 20:30:54,10.5,3,87.52297,94.856868,0,,3,30
https://data.meereisportal.de/download/buoys/2019P201_300234068912800.csv

Will look at that if they don't come back tomorrow. Different format so would require some small code changes.

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #572 on: February 06, 2020, 12:13:25 PM »
data updated today, drift headed north west over  the last 2 days. Forgot to change the frame size so the ani is larger. ctr
770 frames@24fps
edit: corrected the longitude labelling.
« Last Edit: February 07, 2020, 12:12:37 AM by uniquorn »

Jim Hunt

  • Young ice
  • Posts: 4525
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 437
  • Likes Given: 30
Re: MOSAiC news
« Reply #573 on: February 06, 2020, 12:47:05 PM »
Kapitan Dranitsyn is in amongst the sea ice, with nothing more substantial leading the way:

https://www.cruisemapper.com/?imo=7824405
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #574 on: February 06, 2020, 01:45:27 PM »
Probably not a bad route. Quite a lot of new refreeze on the way.
unihamburg amsr2-uhh, fjl, jan29-feb5. (north is left)
added a closer look from rammb (north is down)
Great, 3 images in a row with different orientation
Hmm, maybe they'll drop a few buoys in that area. That would be interesting
« Last Edit: February 06, 2020, 07:29:07 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #575 on: February 06, 2020, 08:59:38 PM »
Quote
not a bad route.
The temptation is to sneak along the lee polynya north of FJI. However the Kapitan isn't going to do that as it could easily slam shut, pushing the ship onto the rocks as the wind changes over to forming a lee polynya on the other side or below.

I don't expect the Barents to freeze over: too warm, too shallow, too windy, too mixed, too unstratified, too much Atlantic Water coming in below Bear Island. Every year people get fooled into thinking new ice is forming when the satellite mp4 show the wind has merely blown the ice pack through the island gaps. Again. St Anna trough is more nuanced.

The slide show below shows a couple of ways using Uniq's triple of buoys for patching the database of 196 S1AB images for an additional 34 missing Polarstern locations, a situation that has gotten much worse with the ship in the pole hole.

Basically, the close-in buoys move in parallel curved tracks, more or less keeping their distance and defining a stable triangle. Adding in a known high precision of a nearby date with PS location establishes a fiducial quadrilateral that can be moved and re-located at three buoy points on a frame timestamps that lack a PS location. The lat lon can then be read from the graticule or pixel coordinates.

Mosaic_mult has quit; they were privy to the ship's precision GPS and plotted it even when the Polarstern was off the latest S1AB. Since their images came with high resolution graticules, the earlier lat lon could be read off that (or interpolated from flanking locations on slow dates).

Once a complete set of once-a-day 06:00 locations are known, the track can be drawn in GoogEarth with pop-up links at each point along the path to the radar image, GFS nullschool of that hour, local buoy radar of ice motion, and global AMSRE leads.

Update 1: added a png showing how Polarstern lat lon can be measured directly off S1AB radar scenes: (1) find the ship which is a bright radar reflector with a stable pattern of floes around it, (2) zoom in 1600% with the BAS IWS viewer provided at PolarView, (3) capture the lat lon at the middle of the ship, (4) transcribe the data (5) check to see if consistent with approximate lat lon at sailwx and MET, (6) check on PolarView jpg graticule, (7) repeat on a later date for reproducibility.

Each of the steps can go wrong! Rechecking everything for the date with the biggest longitude anomaly at Reply #427 for 27 Jan 2020 shows the S1AB method seems to have produced an accurate reading of the PS location.

Update 2: added a distance scale to the graticule. Here a 0.1º difference in latitude corresponds to 11.1 km and a 1.0º difference in longitude amounts (at 87.5º latitude) to 4.85 km. These are the dimensions of full graticule grid cells. The buoy graticule may need adjustment;it is added manually after the tracks are calculated.

Here buoys and Polarstern are being plotted to a tenth (1110m x 485) or maybe even a hundredth of a grid cell 110m x 49m). With FoMo reporting a 1000m shear off the port side disrupting the ROV site and bow radar showing multi-km disruptions almost every day, the scale of ice motion distinct from joint passive drift is commensurate with these sub-grid scales.

Note too that GPS readings at extreme latitudes can be disrupted by solar flare, meaning a perfectly functioning buoy GPS will not really be reporting to the accuracy of what it says on the box.

All this means buoy and Polarstern locations need to be taken with a grain of salt. Accuracy depends on the precise timing with respect to leads opening and closing and shearing forward and back.
« Last Edit: February 07, 2020, 02:31:10 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #576 on: February 06, 2020, 11:49:40 PM »
Gulp. Those calculations would be great if my labelling was correct. p193 ends at  87.5737,96.4523 on the last ani. I've corrected the labelling which is still done manually.
« Last Edit: February 07, 2020, 12:16:53 AM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #577 on: February 07, 2020, 10:47:39 AM »
drift update, headed north west again yesterday. Here showing only points and coordinates. ctr

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #578 on: February 07, 2020, 02:27:31 PM »
Quote
how are lat lon of Polarstern calculated from buoys and/or S1AB?
See update in #575. Buoy and ship positions dependnot only on ice pack drift but also on the timing of position reports relative to shears and other displacements which are of comparable scale.

The latest bow radar is showing significant ice pack motion at numerous sites within its viewing window that presumably are representative of a much broader area including the Mosaic experimental sites and beyond.

The 6-hour bow radar imagery is shown together with 6-hour GFS winds but understanding causation requires looking at large-scale two day ice movement on the Siberian side induced by the stationary anti-cyclone between Wrangel and NSI, as displayed well by the ANSRE leads resource.

The Polarstern's floe is being squeezed between two shear plates, the ice accommodates the stress on it by over-rafting into pressure ridges and keels. Analysis continued in #581...
« Last Edit: February 07, 2020, 05:15:15 PM by A-Team »

Tor Bejnar

  • Young ice
  • Posts: 3392
    • View Profile
  • Liked: 615
  • Likes Given: 293
Re: MOSAiC news
« Reply #579 on: February 07, 2020, 02:52:54 PM »
drift update, headed north west again yesterday. Here showing only points and coordinates. ctr
Curious that, although there is no trail of buoy locations, the lat-long grid is erased by the progression of buoy location lat-longs.  Therefore, you can 'sort of' see where the buoys have been earlier in the GIF. (If not one sort of memory, then another!)
Arctic ice is healthy for children and other living things.

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #580 on: February 07, 2020, 04:17:07 PM »
Quote
the lat-long grid is erased by the progression of buoy location
macid's original code uses R gganimate to create the animations. Adding the graticule from plotSvalbard slows down the process by 5-6 times, making a 5m job take 30mins. So I use a tip from A-Team to create the graticule with a 2frame animation, which takes a minute, clean up a couple of buoy dots, delete the second frame and insert it into the long animation at frame2.
Add an alpha channel to the frame, set white to transparent and merge it down to the first frame.
Much quicker, but the buoy paths overwrite the grat as they go along.
It's eco, saving the planet by using less processing power lol
mostly running on solar for 8mths/yr

Had a look for KD on S1B but all I could find was this. Looks more like a plane. cffr

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #581 on: February 07, 2020, 05:10:51 PM »
Quote
lol
The circle, arrow and text overlay tools are confusing in ImageJ. Set the palette color, draw the overlay on the ROI, then Edit --> Draw to flatten your overlays into the base image. Otherwise the overlay will disappear with no undo! Maybe try RAMMB to locate the KD, rotate that by 105º CW and rescale to overlay on the jp2 version of PolarView which has mouse-over lat lon.

The prospects for the KD not being able to reach the Polarstern at all or getting permanently stuck on the return trip (with all the leg2 scientists aboard) are a definite concern.

Continuing the analysis from #578, the Polarstern's floe is being squeezed between two shear plates that hit at oblique angles with a delay of six hours or less, first from the left (port bow) and then from the right (port quarter). This is one of the few sequences where the coupling between events can be seen cascading throughout the bow radar view as the ice accommodates the squeeze by over-rafting into pressure ridges and keels. The mp4 is rotated 90º CW; the b/w scale bar is in multiples of the 118m ship length. The Polarstern's bow is at the b/w hemispheres, the stern is at the end of the first black bar.

The Ascat pair supplements the AMSRE leads pair above but shows the active and inactive zones more clearly in the two difference frames. The GFS anti-cyclone is above the active zone; the thick and resistant central MYI is more or less immobile. The Polarstern was on the boundary between the two zones.

Band 15 etc at WorldView are partly obscured by clouds and has confusing radial swathing so an ice motion pair there is not feasible.

The gangplank and Ice Camp area are abaft the starboard beam...
« Last Edit: February 07, 2020, 07:39:49 PM by A-Team »

blumenkraft

  • Young ice
  • Posts: 4402
  • Fans of Hans Ø Club - circa 2018
    • View Profile
  • Liked: 1502
  • Likes Given: 2328
Re: MOSAiC news
« Reply #582 on: February 08, 2020, 11:11:21 AM »
Some points from the recent Arctic Drift Podcast:

The temperatures are low at the moment. Christain Haas talks about that there is less snow cover as expected (half the average) which allows the ice to grow in thickness due to the lack of insulation. Even though the wind wasn't too strong, vast parts of the ice are without snow, high snow dunes on other parts.

Then he talks about the pressure rig observatory. They found algae and fishes with the ROV in cavities.

He mentions the rifts that opened in the vicinity which they are using now to do thermal and chemical measurements and observe how new ice develops.

They found out from ice core measurements that there were sediments in the floe which allows them to make assumptions about its origin. It appears it is from a shallow Siberian shelf.

The helicopter flights seem less of a hassle as it was expected. Haas seems happy everything is working so well with them. Of course, this is important to maintain, clean and activate the equipment, change batteries, etc.

A rotating laser scanner is giving them ice-roughness maps. They categorize ice types this way and use this data for the still to build runway.

The crew change that will replace Lag 3 will be via airplane. They need a 1500m runway with at least 1m ice thickness so plains with weels can land. The development of pressure rigs and rifts has rendered some potential areas useless as a runway.

Link to podcast in German language >> https://overcast.fm/+UIoKtFRps



“I’m an introvert. I’m just different that’s all. I’m so sorry. I don’t have a gun. I don’t do that stuff... All I was trying to do was to become better. I’ll do it... You all are phenomenal. You are beautiful. And I love you. Try to forgive me. I’m sorry.”

Elijah McClain

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #583 on: February 08, 2020, 12:12:41 PM »
PS drifted gently north yesterday, shorter timescale, feb1-8
256frames@12fps -updated below
KD heading for a lead at 0320utm this morning, 88 82.25N 68.77E, barely visible on the jpg
https://www.polarview.aq/arctic, not sure how long this link to the jp2 viewer will last
Latest position from cruisemapper is 82:39'35", 74:23'58". It appears to be following the line of the lighter, probably newer ice

edit: Cruisemapper Local time 2020-02-08 19:31, sailwx data stops on feb4

« Last Edit: February 09, 2020, 11:26:24 AM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #584 on: February 08, 2020, 02:52:00 PM »
It's rush hour. Which is KD?

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #585 on: February 08, 2020, 03:47:54 PM »
Quote
82.25N 68.77E, barely visible on the jpg
not sure how long this link to the jp2 viewer will last.
A lat lon time for KD on sailwx or cruise locators to remove white dot ambiguity and identify interlopers? Not seeing a swath, maybe seals up too fast or takes thicker ice or they've been in a lead.

Links last many months, unlike at the PolarView portal which only stores the jpg for 30 days. The url preserves the all-important auto-generated hexadecimal, here 46F8_N_1, which is essential to finding the big package on the awkward Copernicus Sentinel portal. The bslmagb.nerc-bas.ac.uk/iwsviewer/ is a huge breakthrough for the end user.

I've safely archived all the jpgs and lossy jp2 links containing the Polarstern back to Oct 4th mooring. The attached cvs contains direct viewer links to all the jp2 scenes as well as to GFS weather of their date and hour.

Below all 373 scenes to date of Polarstern bow radar are collected in two mp4. The second of these (3x) examines the history of the peculiar area just in front of the bow that has seen bad shearing but has since been stable for months. These are uniformly brightened and sharpened with mild local contrast (CLAHE 63 1.75 in the montage).
« Last Edit: February 08, 2020, 05:54:59 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #586 on: February 09, 2020, 11:25:08 AM »
Headed steadily north west
155franes@12fps
Chaperone? 82.85N76.0 and 82.88N76.77

« Last Edit: February 09, 2020, 12:51:02 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #587 on: February 09, 2020, 02:16:08 PM »
KD is making good progress two hours later. It measures ice thickness, not by the silly system of people comparing a painted yardstick to overturned ice but by a EM induction instrument projected from the bow.

This totals thousands of km of swath data by now that would have helped in comparing various observational and model approaches to this key parameter. However the thickness will not be divulged until 2023 when no one will have the slightest interest. [We call this 'dog in the manger' science after an Aesop fable.]

The KD is in a dense coverage area of S1AB; however we won't see the PS and KD join up because the PS is going ever deeper in the pole hole this week to 88.0º.  We can expect the KD to use its previous track coming in so as not to create yet another damaging swath near the study area.

Quote
At the three L-sites within the MOSAiC Distributed Network (~15 km distant from Polarstern at the beginning), the project will install Atmospheric Surface Flux Stations (ASFS) that include measurements at 0-3m height of pressure, temperature, relative humidity, high-frequency three-dimensional winds, high-frequency water vapor and carbon dioxide concentrations, surface height (snow depth), surface infrared temperature, surface heat flux, and up- and down-welling longwave and shortwave radiation.

Adjacent to these atmospheric surface flux measurements at each of the four locations will be an ice mass balance buoy for measuring ice thickness and thermodynamic structure, and an Autonomous Ocean Flux Buoy for measuring ocean fluxes of heat, momentum, and salt. Jointly these measurements allow for a full documentation of the thermodynamic state of the sea ice.

Additionally, an array of GPS position buoys will be installed across the full MOSAiC Distributed Network to provide detailed information on ice dynamics.

https://epic.awi.de/id/eprint/50082/1/Expeditionsprogramm_PS122_leg2.pdf  page 36
The Polarstern lost an important piece of remotely deployed atmospheric flux equipment yesterday; unfortunately the Kapitan Dranitsyn is not bringing a replacement as it had already left before the pressure ridge occurred. Mosaic did not share the previous loss of function of this device, its earlier repairs, nor even its approximate current location.

This used up quite a bit of helicopter fuel; the KD will be bringing more. However between legs 3/4, only planes can reach the PS. The 1500m runway is very much in doubt currently due to constant development of pressure ridges, leads and offset shears. Planes are primarily for staff exchange; they cannot bring in fuel.

This hole by the gangplank ... what were they thinking? It freezes over from cold ice on the sides (so use 4x8 marine plywood insulated with foam) and from the cold air (use 8" foam board cover, not a complex flimsy tent that cannot be set up in wind). Any lumber yard in the US would have these. Immersion heaters? -- the hole is not even hot tub-sized and just a few meters from ship power supply. $29.95 per 3000W @ ebay.

We have seen so many times that gear testing back home (Bay of Bothnia? ice-fishing in Minnesota?) would have greatly reduced data downtime at Arctic drift sites. No record of downtime has been disclosed and never will be.
« Last Edit: February 09, 2020, 04:22:21 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #588 on: February 10, 2020, 02:16:59 PM »
drift update, still headed north west, picking up speed again.
No polarview of KD area today so here is best I could find through cloud on rammb day/night band ctr
Lat line is 82.5N
KD at 83.7N 79.73 at 2020-02-10 19:00 local time https://www.cruisemapper.com/?imo=7824405
« Last Edit: February 10, 2020, 03:27:13 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #589 on: February 10, 2020, 03:04:08 PM »
Quote
still headed north and west, picking up speed
This Polarstern drift will continue strongly in this direction for several more days due to a persistent anti-cyclone to the north of Wrangel Island. Tailwinds will reach 10-12 m/s which are sub-gale strength.

The ship was at lat lon 87.8 91.7 at 1200Z today and will reach 88.1 86 later in the week, putting them in peak transpolar drift position. The concern has gone from them milling about for months in the Central Arctic to reaching the Fram four months ahead of schedule.

Fram export has really picked up under these wind conditions though it has been steady since mooring. It's very unusual to see the Fram  'intake funnel' of curved concentric leads extend up and past the north pole. This development will become even more extreme this week; the significance is the last of the very oldest and thickest MYI is being drawn down towards export.

The Fram situation seems completely uncoupled to the Nares-Banks Island ice above the CAA. Nares export has ceased for the time being.

An unusual collision of a very large ice plate with the Mosaic floe happened yesterday a couple of km off the bow over just six hours. A small pressure ridge much closer to the Polarstern has also developed off the port bow in the vicinity of the proposed airstrip.

If L Kaleschke is able to add a few earlier years to the lead visualization archive, it might be possible to test the proposition that ice motion has really gotten worse this year. These leads add a large number of trackable features allowing much higher resolution to description of motion.
« Last Edit: February 10, 2020, 04:43:01 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #590 on: February 10, 2020, 05:11:40 PM »
Polarstern just visible on rammb north of the 87.5N graticule.  https://col.st/a1WSn

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #591 on: February 10, 2020, 05:45:04 PM »
This seal is a very long ways from the nearest open water. No photo of it on FoMo today. Seals don't just dive and take their chances on finding the next open lead when they need to breathe -- so presumably a maintained breathing hole is near the Polarstern. Ringed seals will also use cracks and gaps in the ice cover (such as tracks from relief icebreakers?).

Ringed seals have 2.5 cm long claws on their fore-flippers and can dig holes through 2m ice. The ice at the ROV hole is just over a meter thick; maybe the seal will do a better job of keeping it open.

But how can they catch fish underwater in mid-winter when it is dark already on the ice surface  and much darker below? They hunt under the ice for schooling fishes (particularly polar cod) and pelagic invertebrates but possibly also copepods etc living on the underside of the ice probably using whiskers.

Quote
Six seal species live in the Arctic: harp, hooded, spotted, ribbon, ringed, bearded. The latter two use breathing holes in the ice. Most of the ringed seals' time is spent near shore ice, but their ability to maintain cone-shaped breathing holes—which the animals excavate in the ice using the claws of their front flippers—allows them to occupy areas much farther from the ice edge than other seals can reach. Physiological adaptations help them make deep, sustained dives, reaching depths of 300 feet and remaining submerged for up to 45 minutes. But before surfacing, they sometimes blow bubbles up their breathing hole to check for polar bears, their main predator.

https://nsidc.org/cryosphere/seaice/environment/mammals_seals.html
https://www.nationalgeographic.com/animals/mammals/r/ringed-seal/

Feb 4 https://twitter.com/CKatlein
Today we had a #seal in the #ROV hole, and a fish in the zooplankton net.
Almost the entire ecosystem, except the top predator... yet #icedrift
·
Feb 3: so was it strong or weak?
Today we measured #seaice strength with a Borehole Jack from #NTNU #icedrift

See: Engineering Properties of Sea Ice
Journal of Glaciology 19(81):499-531 1976
DOI: 10.1017/S0022143000029476

Feb 2: more gear sank:
After moving operations from yesterday to today due to windchills down
to -59°C, we were deploying sediment traps with the #ROV again.
Unfortunately one had to be sacrificed to Neptune.

126 buoys deployed, 87 time series available:

Während der MOSAiC Expedition wurden bereits 126 Bojen ausgebracht. Die Daten und Messzeitreihen [time series] von insgesamt 87 Bojen können jetzt schon über http://meereisportal.de abgerufen werden. 
« Last Edit: February 10, 2020, 10:31:02 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #592 on: February 11, 2020, 01:12:41 PM »
drifted westnorth yesterday ;)

Quote
Christian Katlein@CKatlein
26 Jan
When he realized, that he won't drift to the pole, #Nansen went North by
skis. As we likely passed our northernmost point, we did the same ... As
we are already 150km further north than he ever reached, we only walked
for 1 hour and camped only 1 night to test our survival
Maybe they'll go camping again  https://twitter.com/CKatlein

tech note: nullschool locations are from p207, the northernmost buoy. The title is incorrect. It should say P201, 204 and 207. P193 often, but irregularly, misses ~2hrs of data so I went back to 201.
« Last Edit: February 11, 2020, 02:12:32 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #593 on: February 11, 2020, 03:09:38 PM »
So many bright dots on S1 images. cffr (07:01:03 today)
KD 84.1N81.4E 2020-02-11 18:57 local time
« Last Edit: February 11, 2020, 03:23:43 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #594 on: February 11, 2020, 09:24:59 PM »
Quote
PS flew west & north yesterday 
Another 48 hours of that coming. The Polarstern reached new lat and lon records of 87.8 89.2 at 19:00Z which is 245 km from the pole and 919 km from the entrance to the Fram Strait. The weather pattern is pushing the whole Euro side of the icepack in that same direction.

That is shown in a 62-day Ascat below. The darker areas are thick MYI ice; significant pieces of it (though not the Lincoln Sea and west) will irreversibly enter the export staging area if the GFS winds keep up as expected. Not unrelated: the Arctic Oscillation index just hit a new high.

The bow radar we've been looking at is a ~10.0ghz product called a sigma S6 Ice Navigator system made by Rutter Inc of St Johns NL (https://rutter.ca/ice-navigation/). It's also been installed on the Healy and RV Lance.

The radar is operated by bridge command only and never before have scientists requested it for Polarstern research. The 1.5m wide X-band antenna is mounted on starboard side of platform B in crow's nest.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JC012387

It does not seem to have been configured properly (to compensate for motion using feedback from gyros) resulting in images not nearly as sharp as they could be. The whole control panel has been cropped out in the meereis archive.

The basic purpose when the Polarstern is underway is distinguishing between open water, ice pans, open water leads in ice fields and ice ridges that can trap icebreakers. In open water the ice radar detects small bergy bits and growlers (large and small glacier calving pieces) that can significantly damage a vessel.
« Last Edit: February 11, 2020, 10:01:30 PM by A-Team »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #595 on: February 11, 2020, 09:32:45 PM »
Quote
persistent anti-cyclone to the north of Wrangel Island.
Hopefully not too far off topic, that shift is allowing significant leads to open in the ESS.
https://go.nasa.gov/39ujJ38, ESS, feb6-11. ctr
« Last Edit: February 12, 2020, 12:28:38 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 2273
    • View Profile
  • Liked: 1186
  • Likes Given: 209
Re: MOSAiC news
« Reply #596 on: February 12, 2020, 11:38:10 AM »
drifted west and north. Map from FoMo inset
250 frames@24fps. Interesting that the map is Greenland down (Perhaps it is a Nansen original)
« Last Edit: February 12, 2020, 12:09:40 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #597 on: February 12, 2020, 01:16:30 PM »
That is a surprisingly large westward component. And increasing, despite a steady wind bearing. Seems like is it 'should' have been more northerly with less of an eastward component.

Tor Bejnar

  • Young ice
  • Posts: 3392
    • View Profile
  • Liked: 615
  • Likes Given: 293
Re: MOSAiC news
« Reply #598 on: February 12, 2020, 02:54:35 PM »
If "North" is to the lower left of the GIF, aren't the buoys drifting northeastward?

Also, I'm confused with A-Team's "... surprisingly large westward component ..." and "... less of an eastward component."  [The "eastward component" is what I see in Uniquorn's GIF.]

I'll be glad to be straightened out!
Arctic ice is healthy for children and other living things.

A-Team

  • Young ice
  • Posts: 2547
    • View Profile
  • Liked: 360
  • Likes Given: 29
Re: MOSAiC news
« Reply #599 on: February 12, 2020, 04:41:41 PM »
Quote
Polar coord directions are confusing! Winds from the south? Not terribly descriptive at Pole. Being straightened out on the earth ellipsoid would be quite uncomfortable.
One way to remember is the "Far East" (in the eurocentric view) is Asia. Western Europe is west of that though east of the US East Coast which is west of the UK.

It all revolves around the Greenwich meridian. That runs through the center of the Fram Strait west of Svalbard. Going CCW from there is east; CW is west. The Polarstern is steadily losing east longitude (0.1º per hour) because it is going west towards the 0º meridian. Our maps use 'Greenland down' which is 45º west rather than a 0º vertical.

The leg 1 Polarstern staff voted to have all their maps point north. Maybe we could vote, though the world would take little note, to make east west and west east and move the 0º meridian to Greenland? How would that work for the South Pole? Let's not go there.

The mp4 follows ultra-local bow ice motion during the time the Polarstern has been under steady tail winds straight from 110º (time frame of Uniq's #596). These winds will perhaps continue another 81 hours to 02/15/0000Z (it's 20-02-12 15:00 now).

The question is, where will the PS track be by then? 88.05 79ºE. Will there be extreme motion in the bow radar and if so, why then and not the last two days?
« Last Edit: February 12, 2020, 05:25:52 PM by A-Team »