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A-Team

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Re: MOSAiC news
« Reply #500 on: January 16, 2020, 01:31:38 PM »
Not understanding what is meant by "*3.6 is only 0.76km/h". Otherwise seems like either the buoys are not reporting in m/s as we thought (knots?) or the scale on the Mosaic map was miscalculated or it's in different units than labelled.

Meanwhile, the Polarstern is out of S1AB range. Mosaic also has access to various quasi proprietary radar data but those satellites too would be in near-polar orbit and not necessarily have a smaller pole hole than Sentinel.

Bow radar is not reporting either. The Polarstern has been in double digit m/s winds for 31 hours now which may be causing a lot of disruptive ice motion and downtime for deployed equipment. That could be the reason for non-reporting; "Follow Mosaic" is posting silly nonsense too.

Quote
Highest P204   2019-Nov-18 85.86  121.25   0.424m/s  1.53km/h

That date had high winds but not much bow radar ice motion. However the passing cyclone picked up again on 2019-Nov-21 causing the worst icepack disruption of the trip, gif below. Sailwx reported mild winds over this time frame; P204 etc were moving quite slowly according to the m/s column in 2019P204_300234068916790_proc.csv

The explanation is at GFS-nullschool: the ice was being 'drawn and quartered' at the Polarstern's location.
« Last Edit: January 16, 2020, 01:53:17 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #501 on: January 16, 2020, 03:56:32 PM »
Quote
Not understanding what is meant by "*3.6 is only 0.76km/h". Otherwise seems like either the buoys are not reporting in m/s as we thought (knots?) or the scale on the Mosaic map was miscalculated or it's in different units than labelled.
Apologies for being lazy:  0.212*3.6 is only 0.76km/h  (edited previous post)

I checked the buoy data. Drift is in m/s
From P207
2020-01-15T02:00:26,87.4686,103.3687,0.133
2020-01-15T02:30:25,87.4702,103.3356,0.135

> distHaversine(c(103.3687,87.4686),c(103.3356,87.4702)) = 241.2289m  (lon first)
divided by 1799 secs = 0.13409m/s

close enough for me.
No data for our favourite Pbuoys today so far so I have added T56 and T62 to show drift. edit:updated below
ani data attached as txt
« Last Edit: January 17, 2020, 05:10:56 PM by uniquorn »

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Re: MOSAiC news
« Reply #502 on: January 17, 2020, 12:55:27 PM »
Winds are a-changing and the Polarstern is heading back south and shortly to the east, where GFS has it caught in another 'drawn and quartered' stress situation very similar to the 21 Nov 2019 pattern above.

The bow radar archive is not currently updating. The ship will remain outside of radar satellite range though conditions can still be monitored by wide-swath/low resolution tools such as Ascat and proxies such as the three close-in P-buoys.

The persistent wind off Siberia that has brought the frozen-in Polarstern so far west and north towards the Svalbard-FJL also strongly affected the icepack in that area. Despite appearances on AMSR2 and Smos-Smap, this has nothing to do with intrusion of Atlantic Water, delayed freezing, early melt, or thinning ice (though those are all important in their own right).

Instead, the massive rifting of wind-blown ice is caused by export into the Barents. Watch the Svalbard island (Kvitøya) marked with the rectangular black dot. A large piece of light-colored ice can be seen swinging around into the Barents. Kara Sea ice is also moving chaotically but not systemically intruding into the Arctic Basin. There is also substantial advection of ice Fram-ward.

The slipstream (wake) of ice moving past small islands is very distinctive and can be tracked for many months in some years. It is a different type of feature than a buoy or virtual buoy in that it has linear extent similar to this year's clear boundary between FYI and MYI on Ascat.

Since the buoys are more or less drifting in tandem with each other and the Polarstern, it suffices to look at a single close-in buoy such as P204. Despite some glitches, its database has excellent quality with over 4600 half-hourly reads of position. The basic statistics are shown in the graph below.

A lot more could be done such as acceleration, correlations with latitude and longitude, and the relationship with hourly sailwx wind speed and bearing.

It is also easy to make a Google Earth trace of the 4600 line segments hexadecimal-colored by speed bin (GE uses hexadecimal, with transparency controlled by the alpha channel AA in #AARRGGBB 0-255 hex). Maximal value (255 dec, FF hex) means fully opaque.. The underlying kml provides a small distributable, extendable and scalable text file. Even though it refers to a buoy rather than the ship, its very high positional and temporal accuracies allow it to track the Polarstern's drift very satisfactorily.
« Last Edit: January 17, 2020, 09:11:25 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #503 on: January 17, 2020, 05:20:01 PM »
Eyeballing the drift chart it seems acceleration/deceleration is easing off as the ice gets thicker.
drift update with change in direction as noted above. Pbuoys are back but reporting later so the 2 Tbuoys stay in.
edit: updated below
« Last Edit: January 18, 2020, 05:40:30 PM by uniquorn »

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Re: MOSAiC news
« Reply #504 on: January 17, 2020, 05:48:36 PM »
Quote
acceleration/deceleration is easing off as the ice gets thicker
Certainly plausible. Maybe one of the SIMBA buoys would provide an ice thickness track. Correlation isn't causation but it's a good start. More ambitiously, integrate bearing (wind direction) from sailwx: might be harder to go north because the pack is run up against Greenland.

Here is some machinery that plots the same track colored for either speed or acceleration. It could be animated, tediously. I haven't binned the speeds into colors yet, just changed every tenth one as a marker. Meant to do 24 hr intervals (48 lines of P204 data) but did 40 bins instead which gives 115 line segments. (Any interval can be set rapidly; it is just modular arithmetic + sort on the count field).

This just uses lon lat sandwiched in between default kml gibberish. A segment needs two consecutive lon lat (from adjacent rows) followed by 'fill down' in a spreadsheet. A flatfile database can't do this, that's the difference between db and ss.

Attached are the slightly dated P204 database to from 10 Oct 2019 to 15 Jan 2020, the spreadsheet column magic that makes it work and the concatenated source (kml is insensitive to carriage returns etc so it compacts well even before compression to kmz).

Update: bow radar just came in with 16 new frames (and 1 new gap) bringing the archive up to Jan 17th! There is a substantial new instance of a large plate sliding 110 m along a previously established (Jan 1st fracture, small slip Jan 6th) shear line on the port side without snapping back or a lead opening (frames 9-10, another possible consequence of thicker and mechanically stronger ice. There are various other motions that don't involve large displacements. Recommended: open the avi in ImageJ as it has very convenient subsetting and speed controls.

https://data.meereisportal.de/maps/animations/Iceradar/?C=M;O=D
« Last Edit: January 18, 2020, 12:03:20 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #505 on: January 18, 2020, 05:44:12 PM »
drift update, jan14-18, with a burst of speed heading away from the pole, perhaps due to less resistance. Will look at adding wind speed/direction to the plot.
updated below
« Last Edit: January 19, 2020, 07:45:38 PM by uniquorn »

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Re: MOSAiC news
« Reply #506 on: January 19, 2020, 05:28:11 PM »
Bow radar is steadily updating now. The ice is still shifting around in fairly minor ways, first port and then starboard; it is hard to predict if any of these are disruptive to experimental setups. The ship is currently at 87.4 98.3 20-01-19 15:00 3 70 in calm air but in a saddle of ice being pulled this way that according to GFS may show up in dramatic ice radar tomorrow. It does not look like S1AB coverage will resume next week.

The provisional bow radar availability mage is generated by the code below, concatenated over all 00:00 UTC locations from 27 Oct to 19 Jan. It displays the gaps in ice radar archive (red) with lat lon as provided by drifter P204. The ice radar archive does not cover October (4 blue days).

As Uniq notes, all the nrt databases are raw nuisances in terms of missing and glitchy entries, so integrating two of them involves a fair amount of editing of spreadsheets, grepping text and coddling of GEP kml.

Next up: integration with the velocity and acceleration proxy Polarstern track databases for an all in one extendable GIS-interactive scalable rotatable display with optional quantitative coupled data capture. It is easy to spoof lat lon slightly so different data types lie side by side.
  • extendable: update path exists for incremental incoming data
  • gis-interactive: provided by multiple co-registered layer checkboxes in GoogEarth
  • scalable: provided by GoogEarth display
  • orientable: provided by GoogEarth display to fit satellite views
  • numeric data: view kml as text, reconstitute as spreadsheet.
Very people on the forums download or use free and easy double-click viewing tools such as ImageJ, Gimp, QuickTime or Google Earth which limits effectiveness given forum limitations.

A row of the bow radar database and its sandwich code looks like this:

296   263   12  Jan 2020   00:00   00   missing   44   -   ffd53e4f   12 Jan 2020   109.8739   87.2192   0.138   "<Style id=""sn_ylw-pushpin""><LineStyle><color>"   ffd53e4f   "</color><width>4</width></LineStyle></Style><StyleMap id=""msn_ylw-pushpin""><Pair><key>normal</key><styleUrl>#sn_ylw-pushpin</styleUrl></Pair>"   <Pair><key>highlight</key><styleUrl>#sh_ylw-pushpin</styleUrl></Pair></StyleMap>   <Placemark><styleUrl>#msn_ylw-pushpin</styleUrl><LineString><coordinates>   109.8739   ,   87.2192   ,0    111.464   ,   87.1618   ,0    </coordinates></LineString></Placemark>

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
<Document>
   <name>Polarstern bow ice radar.kml</name>
</Document>
</kml>
« Last Edit: January 19, 2020, 11:38:19 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #507 on: January 19, 2020, 07:45:06 PM »
drift update. Another handbrake turn.
12 fps
edit: updated below
« Last Edit: January 20, 2020, 02:55:29 PM by uniquorn »

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Re: MOSAiC news
« Reply #508 on: January 20, 2020, 01:51:29 PM »
Quote
handbrake turn
And that's with 30-minute frames. Would there be even more swerves on the 10-minute buoys?

The wind field out there has had a quite unusual configuration and it's about to get weirder in the next hours if GFS 3-hourly can be believed. The final frame on the animation is an hour later than the link below; the second frame of the slide show is 24 hours later

https://earth.nullschool.net/#2020/01/19/0300Z/wind/isobaric/1000hPa/orthographic=-40.24,92.69,3000/loc=97.400,87.400

Meanwhile action has picked up on the Polarstern bow radar, with a new feature appearing in the last 12 hours on the port side but a couple km from the ship (far right). Quite a few missing scenes were patched yesterday to the point 2020 now has a complete 6-hourly record. October is still missing entirely; the ice may have been too flat then to give a good radar reflection. Again, it was not a good idea to conflate bearing with the ship-axial coordinate system.

The imagery can be improved quite a bit by fitting a cubic LUT to the initial contrast that brightens the dark edges and darkens the bow brights, then applying adaptive contrast followed by slight unsharp mask. This evens out the overall contrast, improves it locally and takes off some of the blur from the return signal that broadens with reflector distance. The negative sometimes provides more clarity and it's easy to pair both (2x enlargement below).

The Polarstern was within lat lon range of both Sentinel A and B this morning but no shots were taken for unknown reasons. If Mosaic has ordered up radar from other satellites, they're not sharing it. The last available S1AB scene dates to 05:54 on Jan 14th; the ship will soon be drifting deeper into the pole hole.

'Follow Mosaic' on Jan 18th reports on multi-faceted studies of a pressure ridge (Fort Ridge) whose location is not disclosed. It is up to 7m thick in places. Note this has to be measured directly rather than inferred from freeboard because voids affect density and ice may be held up locally rather than be at buoyancy equilibrium. The ROV has not yet imaged the keel from below.

Seasonal evolution of ridges is quite complex. Four were studied for six months during N-ICE2015 but even then the question remains of how representative they are of the whole Arctic basin:

https://www.researchgate.net/publication/324912186_Decay_phase_thermodynamics_of_ice_ridges_in_the_Arctic_Ocean
« Last Edit: January 20, 2020, 02:59:39 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #509 on: January 20, 2020, 02:54:37 PM »
Drifting gently northwest.
Forgot about the 10min buoys. 2019O1 temperature chart. cffr. A couple of interesting moments there.
Comparison of the 5 Obuoys with P204
« Last Edit: January 20, 2020, 04:23:46 PM by uniquorn »

uniquorn

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Re: MOSAiC news
« Reply #510 on: January 20, 2020, 04:40:55 PM »
Close up on 2019O4 ctr
Added overview of temperature at 100m and whoi itp102 profile contours. cffr
« Last Edit: January 20, 2020, 11:45:46 PM by uniquorn »

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Re: MOSAiC news
« Reply #511 on: January 20, 2020, 05:18:28 PM »
This is getting interesting. We may be getting to the bottom of the barrel in terms of resolution though if the Polarstern is actually recording 1-minute GPS, they could be seeing yet more squiggles, ie icepack motion may be ~fractal. Some of these buoys can be reprogrammed from afar to take more frequent GPS though few would consider it because of battery life and iridium expense.

Below is a provisional (or slightly less) run at displaying acceleration. With speed, we are actually displaying velocity with color + track because the direction part comes for free as tangent to the track.

There didn't seem to be enough decimals in the 30-min velocities to difference them meaningfully to 30 minute accelerations. It seemed better to averaged over 30*8 = 4 hours or more before  differencing, coloring by bin, and displaying using first lat lons (because average lat lon won’t lie on the actual track).

Somewhere along the line my P204 spreadsheet got behind the times and very confused so this will take a restart with a fresh download and rethink of the vector direction aspect (same direction as applied force so would give the latter, so in effect fitting circle at each point along the velocity track). This is an easy spreadsheet calculation from rolling triples of points and Menger curvature (see wiki) though it requires a prior haversine of points n-1 and n+1 distance.

https://physics.stackexchange.com/questions/98420/what-does-the-magnitude-of-the-acceleration-mean/98423
« Last Edit: January 21, 2020, 01:52:24 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #512 on: January 21, 2020, 02:50:46 PM »
A closer look at the dip in ocean temperatures on jan2-3. Any ideas?
edit: added salinity
edit2: Got a surprise when looking at T68 temperatures at 2cm intervals. Will have to thin them out a bit.
Tech note: the first two or three lines are temps at the bottom of the ice
also added O and T relative buoy positions.
« Last Edit: January 21, 2020, 08:22:49 PM by uniquorn »

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Re: MOSAiC news
« Reply #513 on: January 21, 2020, 05:15:49 PM »
Quote
dip in ocean temperatures on jan2-3?
It seems internally supported so not plausibly an instrument artifact. 'Follow' said at one point that the returning Atlantic Water core was still at ~300m and that would be warmer, not colder. Wind mixed layer out here in the middle of nowhere (86.8 117.0) in 4000 m deep water that was largely ice covered even in mid-summer? Neither tidal mixing nor tidal currents have any applicability at this location.

What are nearby CTD buoys saying about salinity on those dates and how broad an area can be shown to be affected by O-buoys? Double diffusion staircases are mostly across the Lomonosov ridge in the Makarov and Canadian basins with only one known in the Amundsen Basin. How about a turbulent diffusive convective eddy with a thermohaline finger intrusion providing layer mixing?

https://www.nature.com/articles/s41598-017-15486-3
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JC014368
https://journals.ametsoc.org/doi/full/10.1175/JPO-D-16-0265.1
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC012993
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JC012419

Meanwhile, back at near-term Polarstern drift, GFS shows a moderate persistent anti-cyclone bouncing around the basin with the ship assuming various orientations wrt its circulation. This pattern is fairly typical for the current strongly positive NAO (which however is predicted to dissipate by the end of the month).

Recent repairs to the Polarstern's bow radar archive have greatly improved the scientific value of 4x-daily coverage. There is still hope that the 22 remaining gaps will be filled; the 8 off-hour oddities will probably not be fixed, nor will any of October be furnished.

Hardly a day goes by without multiple areas of ice showing significant slippage. The last 36 hours though have not been notably disruptive near the ship. The problem is scaling out the bow region (including ice camp which is studied separately) to a broader view of icepack motion: is the observed ice motion regionally representative? The ship is currently located in the pole hole of all high resolution radar satellites so little information is available.

Looking at the thick colors in uniq's 2nd image in #510 (ºC @ 100m), it seems that the set of buoys provide a very convenient set of 'parallel' tracks that can be used to simultaneously display all manner of data. That is, a buoy's lat lon time can be spoofed with anything from weather to gaps in S1AB to peak ice motion to acceleration to some aspect of its own measurements such as ice thickness or salinity at depth.

It is quite feasible to have a dozen of these 'final frames' parallel the plain vanilla velocity track of the Polarstern. Alternatively, the data can be displayed, at least with GE, as a stack of bar graphs by increasing line width along the equator (by setting lat to 0).
« Last Edit: January 21, 2020, 05:29:01 PM by A-Team »

RoxTheGeologist

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Re: MOSAiC news
« Reply #514 on: January 21, 2020, 06:51:55 PM »
Close up on 2019O4 ctr
Added overview of temperature at 100m and whoi itp102 profile contours. cffr

Why is the salinity decreasing with time? The thickness of the low salinity layer is increasing - I'm going to assume that the ice is thickening and expelling brine so I'd expect the salinity of the water below the ice to increase. Am I missing something obvious? Does it take all year for freshwater input from the rivers to reach equilibrium under the ice?

uniquorn

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Re: MOSAiC news
« Reply #515 on: January 21, 2020, 10:20:39 PM »
Maybe more influence from itp102/mosaic being close to the interface of two very different salinities (according to the model)

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Re: MOSAiC news
« Reply #516 on: January 21, 2020, 10:39:00 PM »
"Any Ideas?" Powerful low on 1st 963 twixt FJL/NZ would have 'called' for water from all quarters, did PS shift?, the high over the Canadian basin side would have 'pressed' some less saline cooler water over Lomonosov, near to but not at the surface, the coarse ice underside creating a stable zone with a sheer close below, may also have halted flow at depth down St. Anna trough?

uniquorn

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Re: MOSAiC news
« Reply #517 on: January 22, 2020, 12:23:46 AM »
Thanks for the ideas. I have a lot of reading/checking to do.
Posting these Obuoy temperature ani's for reference, 10-75m
Tech note: scales are different
« Last Edit: January 22, 2020, 12:30:02 AM by uniquorn »

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Re: MOSAiC news
« Reply #518 on: January 22, 2020, 01:21:45 PM »
Quote
Obuoy temperature ani's for reference, 10-75m
Tech note: scales are different
The buoy sets are slightly different too? It looks like as many as 3 could be run without entanglement. The animation of the final frames and side-by-side are shown below.

Looking at 'Mosaic_multisensor' to see if the Mosaic expedition had access to other radar satellites in addition to what PolarView shows for Sentinel, it appears the answer is no. M_m is still poorly done with no mid-course improvements, with satellite images lacking critical access numbers, provided dates erroneous, 48 hour applicability falsely claimed, too small choice of scale, gratuitous rotations that make comparison of successive images difficult, lat/lon of position not synched with  S1AB and obliteration of the Polarstern region with the red circle. However a precise lat/lon for 0600Z can be read off the images on days no S1AB was taken. A poorly implemented scientific product inevitably raises questions about the rest.

The Polarstern is currently drifting west and more south 'on top' of a meandering anti-cyclone. Actual drift is generally 'to the right' of near-surface wind direction. Accurate latitudes are not disclosed so sailwx will sit at "87.5" even as it declines; longitude is decreasing by 1º per 22 hrs. The inset shows "87.4" is due at about 1800Z (except that wind direction and speed vary by the hour).

Very minor shearing is showing on the most recent day of bow radar. 'Follow' offered a possible explanation yesterday for varying image exposure and orientation: the radar is not gimbaled and so changes its incident angle if the stern swings around or the bow rises/falls (as ice anchors fail). This data could be used to uniformize the imagery but it is not disclosed, The PS also has strain gauges welded along its hull. That data is not disclosed either.

'Despite being solidly frozen into the ice, the forces of wind and currents* affect the ship. Depending on their directions, the Polarstern is pushed against the MOSAIC floe or pulled away from it. The latter strains the six ice anchors, which therefore need to be need to be monitored regularly. Today's check showed that five anchors were properly fixed - however one needed some additional care: Steffen and Andreas found a gap next to the 1.20 meters long metal I-beam. They filled it up with snow and poured water inside. The mix freezes solid almost immediately at the current temperatures of -28 °C.'

* No significant independent near-surface currents are known under ice in the central Arctic Ocean. A paper from N-ICE2015 describes the acoustic doppler measurement process and results; the four floes were located near the tip of the Yermak Plateau, meaning measured small currents were affected by tides, rising Atlantic Water boundary currents, adjacent ice edge, and passing storms; thus it is inapplicable to the Polarstern's situation.

https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JC012391 see 2.2.5, 3.5 and Fig 10
« Last Edit: January 22, 2020, 04:46:21 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #519 on: January 22, 2020, 03:55:30 PM »
Quote
The buoy sets are slightly different too?
Thanks for checking. Just can't get the staff these days ;)
O6 75m NANs
O5 20m 75m NANs
O4 75m NANs
O3 50m NANs
O1 ok
A handy line of macid's original code takes out spurious very high(or low) entries and NANs (not a number) which mess up the nice colours.
There are a few good entries interspersed with a lot of NANs. Maybe I can show only those. I'll play around with it (eventually)
« Last Edit: January 22, 2020, 05:03:51 PM by uniquorn »

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Re: MOSAiC news
« Reply #520 on: January 22, 2020, 05:40:58 PM »
Quote
would check work can't get the staff these days ;)
Would not more wealth inequality be the answer? Indentured R experts might do staff work for peanuts.

Alternatively, a spreadsheet classifying column can finger NaN's as singletons, doubles, triples etc. Pull up each class in turn with a sort, paste in a weighted tuple averaging expression that brings in good date from adjacent rows, and re-sort to initial order. This will cause a re-calc that makes the NaN go away. That expression works equally on databases of buoys, satellite gaps, weather misses and so on.

Just posting a close-up of a sturdy ice anchor that worked its way loose on the Polarstern. There are six of these deployed in pairs. It's not clear whether the anchor is bow or stern (midship is unlikely) nor what happened to its mate. The key to having them work as matched pairs is nrt winching to take up slack without losing the grip on the bollard.

An earlier 'Follow Mosaic' said these were improvised back in October in the ship's machine shop after the ice was found to be too thin to really freeze into. The massive iron shackles and sheathed hawsers are things they would have lying about but six I-beams?

Those beams are now over a meter into solid ice yet somehow one worked its way forward without bending or pressure-ridging the ice forward, possibly compressing porosity channels left by brine exclusion. The I-beam is correctly oriented for optional strength under a unidirectional load.
« Last Edit: January 22, 2020, 05:47:09 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #521 on: January 22, 2020, 09:12:35 PM »
The animation colours don't really display enough detail. The charts show a lot more variation. The cold, occasionally salty, fingers appear to be quite local. O6 really struggling. ctr
tech note: should have picked a later start date, unexpected autoshrink makes text barely legible

uniquorn

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Re: MOSAiC news
« Reply #522 on: January 22, 2020, 10:23:12 PM »
Temperature gradient through snow and ice from T56, T62 and T66. ctr
data2

Quick analysis of T62 on jan22
Therm1-40 above snow
Therm41-47 snow/ice
Therm48-111 ice
Therm111-> ocean see inset

« Last Edit: January 23, 2020, 02:21:39 PM by uniquorn »

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Re: MOSAiC news
« Reply #523 on: January 23, 2020, 04:16:03 PM »
The Polarstern has drifted south, reaching 87.4 at 0600 on Jan 23rd a few hours later than estimated in #518. The ship is still 290 km from the North Pole; the closest approach being 267 km with no prospects for northward drift this GFS week. Indeed a cyclone is foreseen swinging the ship far to the east (undoing a lot of recent westward gains).

The Polarstern is currently 1168 km from the entrance to the Fram Strait at 80.0N 0.0E. It is outside the pole hole of S1AB but its specific coordinates have not been imaged in the last 30 days. The area farther east, off the New Siberian Islands, is hardly ever imaged.

The overall motion of the icepack over the last three weeks is better described as a 'Siberian Slam' against the CAA than TransPolar Drift. Note the boundary between FYI and MYI remains quite distinct and easy to track. Ice radar motion in front of the bow has been negligible the last few days.

FoMo had quite an interesting post yesterday that shows the ROV is back in action after multiple relocations. Its view of the ice underside is key to understanding keels and mapping their evolution over time (eg erosion). We have often wondered why buoys fail; the explanation here is mis-installation.

The Fortress area jumble was not a good choice for a buoy site, better would be an area of flat ice without keels. However those weren't easy to find in early October. Second, the drill hole should be protected with a temporary pvc pipe through which the thermistor ribbon is threaded to its correct location and then frozen in.

The ROV is quite a neat device. Let's hope they release some video rather than just the occasional still. The only previous release was an underwater view of the Polarstern's hull.
« Last Edit: January 23, 2020, 04:41:01 PM by A-Team »

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Re: MOSAiC news
« Reply #524 on: January 23, 2020, 07:47:43 PM »
drift update - see below
« Last Edit: January 24, 2020, 10:35:23 AM by uniquorn »

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Re: MOSAiC news
« Reply #525 on: January 23, 2020, 08:12:54 PM »
Here is an English translation of installment 10 of the MOSAIC podcast that is only available in German on the MOSAIC webpage. It was posted there last Wednesday (15. January) but mainly covers events from mid-December last year, namely the handover from leg1 to leg 2 seen through the eyes of the leg 2 leader Christian Haas.

MOSAIC AUDIO LOGBOOK 10
 
Moderator: Audio Now    Arctic Drift – the audio logbook.

Christian Haas: Hallo, I’m  Christian Haas, I’m the project leader for leg 2. I’m not just a researcher, I’m also head of the Sea Ice section of the Alfred-Wegener Institute in Bremerhaven and I’m very happy to have been chosen to take on this task.

Moderator: The next part of the Mosaic Expedition is in full swing. In the meantime, Christian Haas has taken over Markus Rex’s post and is now the local expedition leader for the duration of the second leg. He and the other expedition participants were only able to reach the Ice Breaker Polarstern and relieve the crew of the first leg after  a long and difficult journey through the arctic.

Christian Haas: Yes, our journey began long before we reached the Polar Stern, in fact on the 27th November in Tromsö, where we went on board the Kapitän Dranitsyn.
There were about 60 scientists including the logistic teams and Polar Bear lookouts as well as about 40 of the Polar Stern’s crew, the sailors that look after us here on the Polarstern. We boarded on the 27th and sailed off immediately, but we  only sailed about 2 miles into the fjord before we had to drop anchor as the ship wasn’t fully prepared for the high seas: because of this we had to lash all the containers on deck and store all the other freight for the expedition either in the helicopter hanger or under the foredeck. Then, sadly, there was a very bad weather forecast that predicted a big storm would be blowing over the Barents sea that would make it too dangerous to sail. 10 metre waves were forecast and the ship is only built to withstand three or four metre waves. Therefore, we had to wait for 6 days in the fjord, off  Tromsö,  before we could start the trip. After that the voyage lasted 10 days, 2 days to traverse the Barents Sea, where the waves were moderate and  most of the passengers took it well. And then we went into the ice along its edge where we safe from the next storm that had already sprung up, causing waves on the open sea. Then we sailed north of Severny island [Ed.: The northernmost part of Nova Zemlya], an island that is part of the Siberian Arctic, and set our course North to get to the Polarstern and that took another 5 days.

Christian Haas: The voyage to the Polarstern was very, very  exciting and we all had great expectations of getting there as soon as possible. To begin with the journey through the ice was relatively rapid, but then from day to day it became slower and in the end we were travelling at an average speed of only 1 knot, so that the people on the Polarstern, who were greatly looking forward to finally being relieved, asked what we had been doing. But the Dranitsyn was just very cautious going through the ice to avoid getting stuck and  so took  her time to get to the Polarstern.

Moderator:  The new crew also had to get used to conditions in the arctic. The ice breaker supply ship Dranitsyn had to make its way in the darkness from waypoint to waypoint until it was only a few metres away from the Polarstern before materials and crew could be exchanged between the 2 ships.
 
(Ed.: SEE PICTURE BELOW)

Christian Haas:  The first interesting thing was that  on the first day of our voyage there was already no daylight, so that we had to get used the darkness. That made our first glimpse of the Polarstern in the distance, after 10 days at sea, all the more amazing and impressive. However, because it was roughly 40 miles distant, it quickly became clear to us that what we were seeing was a Fata Morgana, caused by reflections from air layers, which was itself an interesting phenomenon. Then we received a delegation from the Polarstern that came to us by helicopter from the Polarstern. One of the officers from the Polarstern, was seconded to us. He knew the waypoints and the coordinates and had an exact plan for how we could approach the Polarstern without colliding with any of the buoys which make up the network of autonomic stations around us that carry out automatic measurements. He knew a secure route for being able to get us as close as possible to the Polarstern. This was done very professionally and  in impressive style. The prow of the Dranitsyn approached the stern of the Polarstern to within 6 metres, so that nothing had to be offloaded onto the ice but instead, using the cranes of both ships,  it was possible to transfer freight and personnel between the two ships in both directions at the same time.

 

Christian Haas:  Despite the amazing positioning of the two ships it was unavoidable that we did have to transfer some heavy items from the stern of the Dranitsyn to the Polarstern via the ice.  This was done using 2 cranes in tandem, because items on the Dranitsyn couldn’t be transferred from the aft part of the ship to the front part. Instead, we had to offload heavy items such as helium gas cylinders onto the ice, then they were transported from the stern to the prow with a tracked vehicle and then they were taken up by the crane again to lift them onto the starboard side of the Polarstern. We were very happy, because the ice on the port side of both ships remained very stable, at least to begin with, but on the last day a crack in the ice did appear so that immediately after the last transfers had been completed it wouldn’t have been possible to traverse the crack and transfer the last heavy items from the helicopter deck to the Polarstern..

Moderator:  The expedition members could now make an on the spot appraisal of the situation and inspect the ice floe on which they would be spending the next months. For the first time they were able to see for themselves the cracks and other ice structures from which until then they had only heard from their colleagues and which had had such a strong influence on the expedition. 
Christian Haas:  We of the second leg were now very curious to have a look at the situation on the floe and see all the changes about which we had heard so much and from which leg 1 had had to suffer so much; in particular the cracks that were opening all the time and the displacements that occurred. And, as if pre-ordained, the next cracks appeared on the day of our arrival. One of our first actions was that we had to help out. Some of the instruments, especially the remote-controlled instruments, were standing on the ice in the covered area called  ROV City under which a huge crack had developed, directly under the covered area, and we had to rescue them. There was a lot of speculation about whether the cause might have been because the Dranitsyn had to come so near to the measurement area to access the Polarstern. But I think that it was in general caused by the high drift speed and the strong wind that prevailed at the time and that it was a simple deformation event, Anyway since then it’s been the case that the ice has been very, very quiet. Indeed, actually  that was the only deformation- or  break-up event that we ourselves experienced. Since then the floe has quietened down a lot. We moved the remote-controlled instruments and ROV city to a new site. But we haven’t had to reorganize anything else simply because the ice in the immediate vicinity and in the area where we are making measurements has remained static  and we have therefore been able to concentrate 100 percent on our projects and our measurements and have been able to work unhindered

Moderator: in the next installment you will find out how the new crew has adapted to life on the Polarstern and what progress the scientific measurements are making.

Moderato:  Arctic Drift – the audio logbook

uniquorn

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Re: MOSAiC news
« Reply #526 on: January 24, 2020, 10:34:57 AM »
drift update - see below
« Last Edit: January 25, 2020, 10:51:45 AM by uniquorn »

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Re: MOSAiC news
« Reply #527 on: January 24, 2020, 03:22:02 PM »
Thx psymmo7, very helpful!
Quote
caused by the high drift speed and the strong wind that prevailed at the time and that it was a simple deformation event, Anyway since then it’s been the case that the ice has been very, very quiet. Indeed, actually  that was the only deformation- or  break-up event that we ourselves experienced. Since then the floe has quietened down a lot.
:) requires special skills in translation -- that's not at all what the ship radar shows at the time. Note the sheared ice ramming the port side of the Polarstern on Dec 18th as the Kap Dranitsyn was leaving.

Be sure to set the mp4 on loop to see the eyes, nose, jaws and hand of a feeding sea monster.

There are slow days to be sure but yesterday saw some unusual action when a large triangular piece at the 'bottom' pulled away slightly and then rejoined at a slight displacement. This is not likely to have had any effect on ice camp operations.

Note the oddity at the apex of the triangle: it appears as though a horizontal layer has slid off, exposing not water but, implausibly, a lower horizontal layer of ice. The event is not finished; we need a few frames from tomorrow. The frames are six hours apart; there is no intermediate information.

Looking back to Nov 1st, neither of the cracks making up the triangle sides has been active previously. This is mildly inconsistent with theories that most events represent re-activation of previous faults and weaknesses. Some are, but looking at the overall growth in the white lattice, new fracture lines are steadily accruing.

False claims of aurora discovery at FoMo are exceedingly >:( to scientists who actually work in magnetosphere physics. Given NOAA's 3-day forecast online animation, nullschool 'space' display, and wikipedia's treatment, it's hardly news that the aurora borealis is commonly visible at extreme northerly latitudes. That animation is worth a look for its advanced techniques:

https://www.swpc.noaa.gov/products/aurora-3-day-forecast

If GFS is halfway accurate two days out, the Polarstern is about to encounter strong ccw winds at the top of a cyclone that will take the ship far to the east and south (ie wrong directions).
« Last Edit: January 24, 2020, 04:27:13 PM by A-Team »

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Re: MOSAiC news
« Reply #528 on: January 24, 2020, 10:16:58 PM »
Further analysis of T62 showing temperatures since oct29. From left to right are surface temperatures, the temperature gradient through snow/ice then ocean temps which have been enlarged inset. Thickening ice clearly visible in 2cm steps per thermistor.
Lowest temps on dec27 were -37.75,-37.88,-37.94,-38.00,-38.00,-38.00,-38.00,-38.06(Therm34),-37.62
« Last Edit: January 24, 2020, 10:39:34 PM by uniquorn »

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Re: MOSAiC news
« Reply #529 on: January 25, 2020, 10:50:56 AM »
slow drift
edit:updated below
« Last Edit: January 26, 2020, 01:23:09 PM by uniquorn »

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Re: MOSAiC news
« Reply #530 on: January 25, 2020, 01:05:21 PM »
T59 may be a candidate for FoMo jan22 post. No change in the data after 2019-10-18T03:00:14
It may not be near enough to PS though.
edit: added T56 for reference, data is also very odd. edit2: that's because I processed the heat file. I've removed it till I find out what it is.
« Last Edit: January 26, 2020, 12:06:31 AM by uniquorn »

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Re: MOSAiC news
« Reply #531 on: January 25, 2020, 04:30:20 PM »
Quote
T59?
Mosaic installed a secret array of close-in sensors that use the radio LAN and do not report through Iridium (ie don't show up at IABP or MeerEis). T59's thermistor may also have gone astray in a keel. This is a second type of type of buoy failure: still reporting but not informative, here constant near-surface seawater temperature.

IABP today shows 97 Mosaic buoys of which 19 are no longer reporting at all and an unknown number not reporting like T59. All 6 buoys put out in Dec-Jan 2019 by AWI from the Kapitan Dranitsyn have failed.

http://iabp.apl.washington.edu/TABLES/ArcticTable.php#BumBuoys
Quote
Yesterday, we recognized subtle deformations of the #ice floe in the vicinity of #Polarstern on the ship’s radar. A logistics team went out for scouting: a big lead 50 m wide by 1 km long had formed along a shear zone. A good chance to measure energy & gas fluxes! This was the long-awaited “event”: the chance to measure energy and gas fluxes between the water and air, through the newly formed and older ice. Additionally we carried out a special high resolution survey of the lead with the helicopter-borne laser scanner. It also allowed to study the initial population of the newly forming ice by ice-inhabiting biota.
That's it. FoMo doesn't provide any location data (starboard side? 200 m from bow?) nor mark up one of their own bow radar frames nor provide freeboard or the scan. (The scientists aboard do not write these blurbs -- AWI has a staff of 11 full-time publicists to do that.)

Based on 'subtle' and convenient access to the Polarstern, I re-examined the bow radar images from Jan 14th on at 2.5x enlargement. Sure enough, there is newly active minor lead abaft the port beam. The boxed feature in the mp4 has dimension 0.50 x 0.25 km. The original avi has 80 pixels for 1000m so a 50 m feature will only be 4 pixels wide.

It is not feasible to cover every scale from the hairline shear cracks that tipped over the Met tower to mega leads opening off Banks Island. Various papers have put forth power law fits to scaling but based on unsatisfactory coverage and detail of observational data.

Much more dramatic local ice dynamics is going on at the same time farther off the bow but getting there regularly would present time-consuming logistical problems over rough ice. Bear guards are always needed because cooking odors and curiosity are drawing them in from nearest natural prey sites 100's of km away, just like inland drill sites do in Greenland. 

The minor lead being studied will freeze over in a matter of days at -28ºC. However the real problem will coming from multiple rounds of closing and reopening which are already underway. The final state will be closed up the pressure ridge sense, not closed up as frozen open water. That's because compression events take up any slack during the freezing season: the vast majority of shear and lead events in ~3 months of bow radar have become inactive.

Overall, the ice is too weak and its motion too extreme to accomplish very much of what Mosaic set out to do. And it could get worse if some winter storms set in. GFS is sticking to its prediction of rapid drift towards Wrangel Island starting at 1800Z today. The next 24 hours of drift is suggested below. Winds will be picking up from 6 to 11 m/s.
« Last Edit: January 25, 2020, 09:29:37 PM by A-Team »

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Re: MOSAiC news
« Reply #532 on: January 25, 2020, 11:14:01 PM »
T63 looks like a good buoy, probably deployed on thinner ice, growth is faster and the temperature gradient quite different for a while.

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Re: MOSAiC news
« Reply #533 on: January 26, 2020, 01:24:17 PM »
drift update

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Re: MOSAiC news
« Reply #534 on: January 26, 2020, 03:25:53 PM »
The Polarstern got caught up in strong winds to the southeast at about 06:00 this morning as GFS foresaw a few days back. The winds are not quite gale force but will peak in the 10-12 m/s range and stay brisk for a couple of days.

Under these conditions, longitude will be gained at about a tenth of a degree per hour; in 3 days the ship could plausibly be at 87.2 100.0.

A very dramatic lead opened off the port side, preceded by a possibly enabling large scale shift two km off the bow. The event is still ongoing so we await the next day of bow radar (which unfortunately has become erratic again). In part, an old prominent slipline reopened, not entirely but with new leads taking off at the ends.

Looking at the regional wind stress picture over this time frame, it appears that the problem is not high wind speed per se at the ship but rather its rapid fall-off nearby, ie the stress gradient. How far out that matters is a big unknown, perhaps ice basinwide contiguously adjoined to the Polarstern floe (ie rigid body motion).

I added streaming awiMet ship weather to the ice radar since that wasn't happening at their end. It's a doable nuisance to go back to the Nov 1st start because of almost daily gaps in hourly awiMet weather and unsynchronized missing or unusual radar timestamps. There is enough black space to include a small thumbnail of GFS winds at each of the 320 bow radar frames to date. The  bow to stern length of the ship (9.4 pixels) could also be depicted.
« Last Edit: January 26, 2020, 08:03:47 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #535 on: January 26, 2020, 04:59:52 PM »
Similar activity on a macro scale from rammb, jan22-26. The latitude line is unlabelled but sits between 85 and 90, so should be 9 87.5.  https://col.st/yci9q
edited to attempt to get the centre closer to current mosaic location
Corrected: 97.5 off the planet ;)
« Last Edit: January 26, 2020, 09:30:52 PM by uniquorn »

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Re: MOSAiC news
« Reply #536 on: January 26, 2020, 08:35:37 PM »
Apologies to T56 which is in fine fettle. Probably enough from Tbuoys for now.

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Re: MOSAiC news
« Reply #537 on: January 26, 2020, 09:07:55 PM »
Quote
so should be 97.5
so should be 87.5.

Same Rammb final frame as #535, corrected for this and that. The PS is slightly up and to the right of the red asterisk.
« Last Edit: January 27, 2020, 04:09:36 PM by A-Team »

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Re: MOSAiC news
« Reply #538 on: January 26, 2020, 09:09:12 PM »
Growth is faster and the temperature gradient quite different for a while.

The gradient change (especially when the air is cold!) reveals the boundary between snow and ice.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

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Re: MOSAiC news
« Reply #539 on: January 27, 2020, 01:32:17 PM »
Major fracturing and re-association of seven active ice plates continued today as expected from winds in the 11-13 m/s range with a sharp NS gradient. The bow radar view of 280º degrees includes the port side but not the deployed equipment starboard area which may have been seriously disrupted as well.

Eight hours past the last frame, winds abruptly dropped to 4 m/s as the ship came off the shoulder of the cyclone at 10 am on Jan 27th at 87.4  95.8.

The wind gradient image shows stress on the ice moderate near the pole, increasing to a maximum near the Polarstern and very low an equal distance farther south but all in the same direction. This results in ice moving forward (east) at different speeds across the gradient. That is what is causing the plate commotion as rigid ice cannot move coherently at different speeds. High winds alone are necessary but insufficient for a steep gradient; in a more homogenous stress field the ice pack could simply translate (modulo boundary conditions).

The buoy tracks establish that OsiSaf, which requires two days of data averaging and re-gridding, cannot capture motion at the relevant temporal and spatial scales. While too few buoys are put out to accurately depict ice motion for the Arctic Ocean overall, the buoy array could be used to patch OsiSaf locally.

S1AB rarely covers this latitude. The Polarstern and surroundings have not been imaged since Jan 14th but the ship did show up on the edge of 06:36 image on Jan 27th. That will be nearly the exact time as the first image on bow radar avi tomorrow.

The bottom image shows the jp2 and jpg versions from PolarView. The spatial resolutions (25 pxl/km nominal) do not provide a wholly satisfactory continuation of bow radar scale (80 pxl/km). Very little lead or ridge detail matches. Both can have 3-4x daily coverage, though S1AB arrive in a morning burst and bow radar evenly at 6-hr intervals.
« Last Edit: January 28, 2020, 01:35:10 AM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #540 on: January 27, 2020, 02:01:38 PM »
Recent drift mostly east, a touch north, at speed.
So T56 snow depth 10-15cm, similar to the images on FoMo.
updated below
« Last Edit: January 28, 2020, 11:25:15 AM by uniquorn »

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Re: MOSAiC news
« Reply #541 on: January 28, 2020, 01:53:03 AM »
Here is an English Translation of a transcript of the latest Podcast from the MOSAIC Website that is only available in German.

The Podcast was posted last Wednesday (January 22)  at 5:57 PM on the MOSAIC Website (in German) - the recording itself was probably made 8. January

Instalment 11 – thick ice, four-legged visitors and slight frostbite

In the meantime, the team around the new leader of the MOSAIC-Expedition, Christian Haas, has accustomed itself to life on the ship and to the camp on the Ice Floe. In this instalment the Sea Ice physicist goes into detail about the composition of the ice and how it is continuously changing. Apart from this, Dr. Haas also reports on measurements made by other scientific disciplines and explains how an aircraft landing-strip is made on the ice. The continual decrease in temperatures and the ongoing polar night present further challenges for the members of the expedition. And, this week, the camp got another animal visit.

…..[Ed.: Just so that transcript readers don’t miss out on the atmosphere of the podcast they should know that it is preceded and ended by sound recordings of strong wind and creaking ice….]

Arctic Drift – The audio logbook.

Christian Haas:   At the moment we are at 87 degrees 8 minutes North. During the MOSAIC expedition the ship this the most Northerly that the ship has been. [Ed.: According to the positions reported on MOSAIC webpage this would date the time that this recoding was made a being around 8. January]

Commentator: In the meantime, the leg 2  Team has adapted to arctic conditions. The crew around the new  Expedition leader Christian Haas has familiarised itself  with the Icebreaker  Polarstern and the condition on the home floe. Dr. Haas himself is head of the Sea Ice Physics section of the  Alfred Wegener Institute and can precisely explain what an ice floe is and why the ice in the arctic is constantly changing.

Christian Haas: we are always using the term “ice floe”, but everyone probably imagines something different under this term…and at this time of year, in the middle of winter, there aren’t really any, anymore. When the  Polarstern arrived here at the beginning of October, it really was the case that there were individual ice floes drifting in the water. They were separated from each other by water or thin ice. But the ice and the ice floe formed a unit and could be regarded as a swimming platform.   The MOSAIC ice floe had a diameter on the order of two to three kilometres. But since we have been here and the winter has begun, the whole area around us has frozen solid, so that one can’t make out individual ice floes, because the borders between them are not visible, except with the help of Satellite data. Nonetheless it’s the case that the ice floe isn’t a plate, it isn’t a simple uniform plate of ice, but, as before, it regularly fractures and is displaced by shear zones. Till now we have just had a lot of luck that such shear zones and fractures didn’t go directly through our camp but were some distance away. Just yesterday we made an exploratory tour with snowmobiles to the West and East and at a distance of about two to three kilometres in each direction we found tears and shear zones.  With that we could say that the floe is  two to three kilometres in size, but the Northern and Southern boundaries haven’t been found yet. 

Commentator: The ice and the alterations in it are being constantly observed. Using different kinds of measurements it is possible to completely understand the displacement of the ice. Many researchers view these displacements as a danger, because they can lead to interruption in their research. Others welcome the possibility being able to  observe and analyse them directly. 

Christian Haas: The ship’s radar, that every 10 minutes makes an image of the surroundings within a radius of 5 kilometres, helps us a lot. When one looks at a time series of these images it’s like looking at a film of the ice movement. Most of the time the ice is stable, but sometimes one sees shear events, where, because of a difference in the extent of ice-drift in different regions, a part of the floe suddenly slides by between several metres up to as much as 100 metres relative to the other part. These zones produce tears and the formation new pack ice ridges.

Christian Haas: For most of our colleagues here the tears and the formation of pack ice ridges are seen as a hazard, because they interrupt research. But for us as researchers and  for the whole MOSAIC project of course it’s an important process that we want to investigate.  This is because we want to better understand why the ice in the arctic has declined so much during the last few decades and to find out what processes result in the ice becoming thicker or thinner. The growth of pack ice ridges, the deformation of the ice and the sliding of pieces of ice on top of each other  is a very important process and can make ice much thicker than it would become through solely as the result of freezing through contact with the cold atmosphere. For this reason the sea ice researchers and remote sensing experts who are involved in our project are very thrilled to be able to observe such deformation events at first hand and to be able to see how the ice can continuously become thicker through floes fracturing and sliding on top of each other. 

Commentator: In the meantime, the floe ice is circa one metre thick and has doubled in thickness since the beginning of the expedition in October.  In comparison, the so called “pack ice ridges” are considerably thicker. To investigate them more thoroughly various instruments have been installed in the ice.

Christian Haas: We see here that some pack ice ridges are up to three metres high. Pack ice ridges are like icebergs, that means that roughly a tenth of appears above the surface and nine-tenth of them are under water. It follows that where there are pack ice ridges the ice can be 10, 20 or even more metres thick. We have observed this with our remotely controlled ROV, with which we were able to make  sonar measurements of the ice depth and we have already found ice thickness of over 10 metres. In our last big action, we installed a number of instruments in some of these pack ice ridges. We call this the “Pack Ice Ridge Observatory” and we want to use it to observe on the one hand how the underside is eroded by currents and by the warmth that is present in the sea water and on the other hand  how the pack ice ridges are frozen from above. In addition, we want to know how, because of their rough surfaces, they are affected by turbulence in both air and water and whether this is important for their growth or melting.

Most ice measurements are made by drilling holes in the ice and then placing instruments underneath the ice or in it. That’s exactly what we have to do here. We have placed large measuring devices, that require large holes to be drilled, at the periphery of the pack ice ridges and underneath the ice. These are for instance instruments that measure water currents and turbulence.  Then we embedded thermistor chains over the whole ridge as well as in the thickest ice, that was more than 8 metres thick in places. With these chains we can observe how the ridges cool, how they freeze in the centre, and how the processes of erosion and disintegration  take place on their undersurface.

Commentator: Research in other scientific disciplines is also ongoing. A great deal of weather data is being collected both on the Polarstern and  in the Ice Camp. Still lower temperatures than the current low temperature of minus 35 degrees have been measured there and that has led to one or two expedition members experiencing mild frostbite.

Christian Haas:  By itself the air temperatures aren’t sufficient to judge how cold it really feels on the ice, because it’s the combination of air temperature and wind strength, what’s called “windchill”, or in other words perceived temperature,  that’s important. Unfortunately, some of the coldest periods occurred at the same time as phases when the winds were strongest. Windspeeds went up to 50 km per hour and the perceived temperature fell under minus forty-five, sometimes under minus fifty. This made work on the ice very, very  unpleasant and even almost dangerous. Although we have very good extreme weather clothing, a few people still managed to experience mild frostbite on their faces. This is very difficult to avoid when you are really concentrating on your work and you forget how cold your cheeks, or your nose, is getting.

Commentator: The safety of the team is still first priority. In case there should be a medical emergency, that luckily hasn’t happened yet and hopefully won’t in the future, then expedition members can be airlifted out. 

Christian Haas:  We are approximately 300 kilometres from the North Pole and therefore a long way from any form of human civilisation and from any form of help that we would need if an accident were to occur. Basically, we are further away from help and civilisation than one would be on the international space station.  For this reason, we have made contingency plans for how we would obtain help in case it was really needed. One of these plans is that we could be reached by a light aircraft with skis that could land here and bring help or airlift a sick person out.  However, such an aircraft would require that we have a more or less even landing strip, which wouldn’t be there naturally, because the ice needs to be thick enough - at least 50 centimetres – for the aircraft to land safely. Because of this, during the last few days we constructed a test landing strip close to the ship, so as to minimise our use of  resources. To do this we used Pistenbullys, these are tractors equipped with snow ploughs and rotary hoes [Ed. In English they are also known as “Snowgroomers”]. This Pistenbully prepared a roughly 400-metre-long, 25-metre-wide  landing strip, that is very, very flat – so flat that even an aircraft with landing wheels could land here. That was a very important exercise for us to allow us to  prepare for the construction a larger landing strip that we will need for the changeover between legs 3 and 4.

Commentator: The scheme for protection from Polar bears is also still active, although so far during leg 2 no polar bears have seen. Instead the camp was visited by other four-legged creatures who unfortunately caused minor problems with various measurements.

Christian Haas: The pin up animal for the arctic is the polar bear and we are prepared for them in all sorts of ways, although they aren’t as dangerous as they are often made out to be. But, to our great disappointment, we haven’t yet seen one. This isn’t perhaps so surprising, because in the middle of winter, when its dark and the ocean is almost completely frozen over, there are neither seals nor any other kind of food.  Then the polar bears tend to go South. Therefore, given that our tour of duty was the mid-winter one, perhaps we shouldn’t necessarily have expected to see many of them. But what then  did surprise us, although there are past reports of it, is that we were visited by Arctic foxes. Up to 6 of them were seen. They stayed in the neighbourhood of the ship quite a long time, circling the ship and playing. That was something of an occasion here and a bit of a diversion. Naturally, first of all we thought that the foxes were cute animals and nice to look at. However, actually they presented something of a danger to our measurements because they love chewing cables. And accordingly, some of the foxes chewed through some of the cables that we had laid across the ice to connect measuring instruments with dataloggers, batteries or generators, interrupting measurements. But then we were able to successfully protect the cables against the foxes and were able to drive them away and for the last two weeks there haven’t been any more foxes here and our work could continue unhindered.[Ed.: on the MOSAIC webpage on 6 January a further instance of damage was discovered and  reported and the remark made that the foxes had been seen at “the end of December”] 

Commentator: Christian Haas is looking forward to the coming weeks and the upcoming research work, although the conditions for it won’t be made easier by the continuing polar night and the further decrease in temperatures. He is very focussed on keeping the goal of the MOSAIC expedition in his sights.

Christian Haas:  We are still moving into February and March, that’s actually the coldest season in the arctic. That means that weather conditions will become even more extreme. Nonetheless, I believe we will continue to work enthusiastically on the ice. Because now, just as we are slowly beginning to get good time-series measurements of atmospheric conditions and of ice and water conditions, the information is becoming increasingly interesting and we are getting nearer to fulfilling the goal of the MOSAIC expedition to investigate the interaction between the atmosphere, ocean and  ice and, and we shouldn’t forget that, the Biology of the arctic. So I hope that we will continue to be able to work unhindered. Naturally one or two ice deformation events should also take place, if possible, at quite a distance from the  ship. We will continue to expand the radius of the area that we move in. Apart from that, I hope that we might indeed get a storm that will bring us some snow. Till now the snow has been very sparse, the snow cover is between eight and twenty centimetres. And what we also hope for, even if it may sound paradoxical, is that at some stage we get an intrusion of warm air that will temporarily give rise to very high temperatures and even to a little rain, as has been seen with increasing frequency in past years and about which there has been much speculation as to the effect it has on ice cover and ice growth. We now have a unique opportunity to observe the phenomena on the spot and that is absolutely necessary to better understand these processes. 


uniquorn

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Re: MOSAiC news
« Reply #542 on: January 28, 2020, 11:22:49 AM »
Drift update, testing the brakes before a hairpin bend. :updated below
Added a close up from 27th onwards of the nearest Obuoy (to the north east) which report location every 10 minutes. No drift speed but the ani has 6 frames/hr (at 7fps)
O4 temp/salinity/pressure chart from meereis. That still doesn't make sense to me, a sharp salinity increase but temperature goes down. (legend position is unfortunate, see #521)
edit:Looking more carefully, the spike in salinity is at 20m. At 100m salinity dips with the drop in temperature.
« Last Edit: January 29, 2020, 12:26:39 PM by uniquorn »

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Re: MOSAiC news
« Reply #543 on: January 28, 2020, 07:26:25 PM »
Nice interview, psymmo7. Haas is not correct about ten minute intervals between bow radar scenes. For example, the Nov 11 has two scenes three minutes apart, 12:00 and 12:03.

This is important for determining operational safety. That is, can massive rifts open in seconds or is the time scale minutes, hours or days, conveniently preceded by ample warning noise? They have already had one scientist fall in up to her waist, another to the top of his boot.

On leg 1, they ran out of connectors and could not replace critical cabling buried under yet another overnight pressure ridge until the relief icebreaker arrived. Some of the cracks grew very slowly and could be monitored for days, like the one that eventually toppled and broke the Met tower.

FoMo posted a great graphic yesterday showing open water many meters wide associated with an overnight 5 m pressure ridge that buried their snowmobile track.

Looking through the totality of bow radar image pairs to date, the worst case scenario was the Jan 26th pair 09:57/11:59 (see above mp4), with massive km-scale leads and ridges forming within 2hrs 02min of separation. Quite a wide area was affected over days so it wouldn't take bad luck to be in the wrong spot at the wrong time.

In past years, we have seen cracks propagate from Banks Island to western Siberia overnight, minimally 40 km/hr. The Norwegian airboat camps were hit twice with serious loss of equipment.
Quote
Added a close up from 27th onwards of the nearest Obuoy (to the north east)
Here is the mega track of buoy 201904 back to Day One. The display is generated by the 16,142 points at 10-minute intervals. The attached kml file allows unlimited zoom, rotation, and co-display with other types of tracks such as S1AB availability, bow radar availability, wind direction from sailwx and so on.

The Polarstern's track would be virtually indistinguishable at this scale, with a constant offset from this buoy. The velocity of buoy 201904 is easily computed within its csv and assigned a color palette, as is any scalar quanity (such as salinity or temperature at a given depth) measured by the buoy.

The buoy overview graphic at Meereis Portal is done well; the palette allows selection of individual buoy types and color changes. There do not appear to be any 'snow buoys' or 'other' displayed. Again, this is best done in GoogEarthPro with a folder containing a folder of each buoys class because this allows disentangling the complexity via checkboxes and visitor download of the data generating the image.
Quote
testing the brakes before a hairpin bend
The proximity to the cyclone center could have unprecedented effects on ice disruption.
« Last Edit: January 28, 2020, 08:48:21 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #544 on: January 29, 2020, 12:25:02 PM »
drift update, slow, headed northeast
~11days in 250frames @ 12fps
updated below
« Last Edit: January 30, 2020, 02:41:14 PM by uniquorn »

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Re: MOSAiC news
« Reply #545 on: January 29, 2020, 01:00:47 PM »
Winds are moderate but shifting around quite a bit, with temperatures up 12 degrees from the expedition low of -35º on 20-01-28 (which fortunately had only 3 m/s wind chill). It doesn't seem like barometric pressure has settled into much of a winter pattern so far; this is resulting in a meagre Beaufort arm and back-and-forth in the Fram export area.

All three Ascats are back after several days of shaky downloads to the base stations. S1AB caught the ship on three recent days despite the extreme latitude. Mosaic_multisensor was discontinued on Jan 21st; it needs re-conceptualization.

Bow radar of the last 48 hours shows newly constituted ice plates settling back down after extensive regional shearing earlier. This relaxation process has repacked ice blocks more or less the way they were before. Floe boundaries formed during fall freeze-up have seemingly lost relevance even though the joints are commonly presumed weak and prone to fracture.

FoMo posted a very interesting photo on Jan 27th of a 5m high pressure debris and extensive open lead. The jumble of ice obliterated an Ice Camp road (snowmobile track). The lead has quite a bit of broken ice floating in the water, frozen in like raisins in pudding by now with the temperatures in the -30's.

What probably happened here is the lead opened and closed repeatedly, forcing ice fragments onto one shore. This does not make a proper pressure ridge, no keel. It is clear from the photo that snow accumulation has been minimal (below a boot) and the ice has not thickened much at this site.

FoMo's most recent post shows leg 3 participants loading up for the mid-February replacements and refurbishments. The relief icebreaker is not likely the Kapitan Dranitsyn as stated. The KD is not a proper icebreaker to begin with, cannot function in 3m waves when loaded with scientific containers. It got stuck already leaving in December ice.

The KD has no prospects of reaching the Polarstern nor returning to port in the thicker ice of mid-February. It's hugely expensive to be rescued by a commercial nuclear icebreaker and can involve several weeks of waiting at sea because of prior scheduling commitments. So this will be the Akademik Fedorov doing the exchange.

The 3rd image shows the level of buoy track detail available in GEPro (compare to #541 above). It is a fairly good match to the buoy's GPS accuracy at this latitude.

The 4th animation takes Uniq’s buoy animation in #544, adds red dots to mark each day at 06:00, cuts down to just one of the parallel buoy tracks, adds a GFS wind track out 24 hours from the final frame, and uses that to conceptualize where the buoy will be tomorrow (green line, red dots every 3 hours; scale is off). The buoy is an offset proxy for the Polarstern drift.
« Last Edit: January 29, 2020, 09:15:56 PM by A-Team »

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Re: MOSAiC news
« Reply #546 on: January 29, 2020, 06:55:02 PM »
The relief icebreaker is not likely the Kapitan Dranitsyn as stated. The KD is not a proper icebreaker to begin with, cannot function in 3m waves when loaded with scientific containers. It got stuck already leaving in December ice.

Allegedly the relief "icebreaker" really is the Kapitan Dranitsyn:

https://twitter.com/ArcticPROMIS/status/1222575998564044800

Quote
This afternoon two tugboats pulled the Kapitan Dranitsyn out into the fjord and we began steaming (dieseling? doesn't have quite the same ring) North. Polarstern bound!
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

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Re: MOSAiC news
« Reply #547 on: January 29, 2020, 11:04:24 PM »
update on estimated polarstern position using P201,P204 and P207. Red dots are A-Team's recent calculated locations from S1 images(listed below). It wasn't possible to match all points accurately so best efforts were made at the more recent dates.

jan   Lat   Lon
280538   87.4517   95.8359
270636   87.4444   95.5836
140554   87.3973   105.4119
130335   87.309   107.9954
100627   87.1678   113.0994
70602   87.1201   114.9311
ani data attached as txt

Tech note: formula
dataPS$latitude..deg. <- ((1*data201$latitude..deg. + 2.8149*data207$latitude..deg.)/3.8149)
dataPS$longitude..deg. <- (1*data207$longitude..deg. + 0.002981*data201$longitude..deg. + 0.0028*data204$longitude..deg. )/1
Probably be ok for a few days. Couldn't find a good ratio for Lon
est north   est east   diff   
87.4543334399329   95.6513628566   0.002633439932893   -0.184537143399993
87.4203817793389   93.1496523462   -0.024018220661105   -2.4339476538
87.4016529083331   105.3507199407   0.004352908333118   -0.0611800593
87.3137762221814   108.0140101407   0.004776222181434   0.018610140700005
87.1742587669402   113.2169081828   0.006458766940156   0.117508182799995
87.1259043880573   115.0405318049   0.005804388057342   0.109431804899998
« Last Edit: January 29, 2020, 11:26:19 PM by uniquorn »

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Re: MOSAiC news
« Reply #548 on: January 29, 2020, 11:15:31 PM »
Maybe the AK or another icebreaker will escort the KD? Unbelievable, the KD had to sit in a fjord for six days before the last trip, weather off Tromsø. Gear on deck sliding back and forth.

Or maybe the KD can retrace its last route. We could follow it for weeks as a white track. Not seeing it on the last 3 S1AB though.

Wow, look at the regional ice motion for the last three days. Orientation is rotated 180º to match Mosaic practice. Not quite enough resolution to match bow radar though 06:00 times are favorable.

Looks like we can patch the high resolution coordinate set between the buoys and older mos_mult. Haas might be open to releasing ship bearing and GPS data (?)

GFS is sticking to its story: a cyclone will graze the Polarstern tomorrow. Where exactly is hard to say because intermediate drift affects the details of the ship's position relative to cyclone structure. Scientifically speaking, this is an incredible opportunity to see close-up how the ice pack responds to a fast-moving circulating (and drifting) wind pattern.
« Last Edit: January 30, 2020, 02:46:27 AM by A-Team »

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Re: MOSAiC news
« Reply #549 on: January 30, 2020, 01:32:30 PM »
The ice off the port bow remains restless but continues to settle in. Pressure ridges and keels should be building as ice plates collide but that is not immediately apparent in the two frames, The Polarstern passed through a blast of warm air off the Barents; by the time the air completed the CCW cyclone circuit, it was a whole lot colder. The pink lines from awiMet show conditions at the times of the bow radar frames; the green pressure at 06:00 match the GFS timestamp.