Support the Arctic Sea Ice Forum and Blog

Author Topic: MOSAiC news  (Read 131046 times)

OffTheGrid

  • New ice
  • Posts: 58
    • View Profile
  • Liked: 31
  • Likes Given: 31
Re: MOSAiC news
« Reply #950 on: August 09, 2020, 04:32:51 AM »
I'm sorry, I should have been cleared, I ment the downstream flows down the underwater river canyons can be ninety percent rock, meaning everything from loess to large boulders, and Organic matter, etc. Some call them submarine lahars. Outbursts megafloods are called that because they peak at over a million tons per second.
Haven't heard of anyone getting published on what solids content the flows through the underground lakes and their connections contain, but Its quite visible them emerging from all the NE Greenland glaciers in recent weeks just on worldviews images. Often theres huge outflows and then sometimes  backsurges in the floes on the surface of the deep fiords, as the whole pulse goes through at the bottom. You can see sediment discolouring bursts at the calving  front up to fifty km wide sometimes but the big flow is shooting north from under the rapidly disintegrating ice shelf, with the fragments being whisked away by the entrained surface current. Theres a huge basin below sealevel plugged by those glaciers, and the hydraulic head on the basal lake system is the deep funnel lakes we see repeating in the same places an shapes for the last years over a km above.
Both theses and the big Siberian rivers with flood surges send pulses down the submarine canyons to the deep basins. Which in the Arctic are very much very poorly understood because they are thousands of different bodys of suffering salinities temperatures, dissolved mineral,
organic and fine suspended solids that mix poorly.
The comment about rock melting, this does happen under icestreams, so you'd get superheated steam along with the water expelled into the drainage system, before the runaway rate of melt causes a crash sudden quench and the base flash freezes to the bedrock again. Antarctic ice streams have been documented as pulsing forward at the base up to 100m at several meters per second in this fashion. Don't think Its known if this in sustained fashion occurs in these high speed glacier collapses elsewhere. But if either of these big ones, or the humbolt could that it would be dramatic, uncorking the whole pressurised interior lake system.
The bad news is the anoxic freshwater seeping out of those silt lahars in the deep basin has replaced the downwelling oxygen brine chimneys from lost Ice Shelves and multiyear ice keel that all those scientists were screaming about the direness would result from this loss ten or more years ago.

binntho

  • Nilas ice
  • Posts: 1492
    • View Profile
  • Liked: 499
  • Likes Given: 115
Re: MOSAiC news
« Reply #951 on: August 09, 2020, 08:02:59 AM »
Slightly OT, but from GSA (Rock glacier morphometry, San Juan Mountains, Colorado: Summary)
Quote
Rock glaciers are common periglacial denudation features above timberline in the San Juan Mountains of southwestern Colorado. They occur as porridge-like lobate or tongue-shaped masses of rock and ice which move downslope at rates of as much as 100 cm/yr (Barsch, 1977).
Walking on them in mid-summer, all you see is rock, so "90% rock" might be right.  (Internet searches show rock glaciers occur elsewhere, too.)

But your other complaints are good.

I don't know if cirque glaciers contain more rock per mass than "normal" glaciers. Cirque glaciers rotate so any debris get caught up and will only escape as sand and clay suspended in water that spills over the edge of the depression that these glaciers dig forthemselves.

But having personal experience of glaciers I have never seen one that is more than perhaps 1% rock.

So-called rock glaciers are more correctly frozen avalanches, i,e. when a permafrost slope starts moving, and are quite rare, although there are a couple in  Alaska. Of course, if a moving mass consists mostly of rock then it is not a "glacier" and thus a "rock glacier" is really a misnomer.

I'd guess that it needs low precipitiation to maintain a rock glacier, otherwise a "real" glacier should appear on top of it. And of course, they are presumabley very slow moving - if they move at all?
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

oren

  • Moderator
  • First-year ice
  • Posts: 6192
    • View Profile
  • Liked: 2252
  • Likes Given: 1890
Re: MOSAiC news
« Reply #952 on: August 09, 2020, 08:56:30 AM »
Good or bad, this is off-topic for this thread.
OTG, I recommend finding a thread to post and discuss this stuff in, interesting but not here.

binntho

  • Nilas ice
  • Posts: 1492
    • View Profile
  • Liked: 499
  • Likes Given: 115
Re: MOSAiC news
« Reply #953 on: August 09, 2020, 09:10:02 AM »
Sorry Oren, but if you snip the pseudoscience from OTG's post above, I'll remove this post.

OTG has retreated with all claims except the following:

Quote
The comment about rock melting, this does happen under icestreams, so you'd get superheated steam along with the water expelled into the drainage system, before the runaway rate of melt causes a crash sudden quench and the base flash freezes to the bedrock again.

This should have been snipped since it is totallly unfounded, unrealistic, incredible and without any supporting evidence. We Scandinavians learn in school what bedrock looks like after being covered by a few kms of ice during the deep ice age, and scoring tracks left by big rocks scratching into the underlying bedrock are commonly seen. Surface melting is never seen, and just to imagine that it could happen is indicative of a total lack of scientific reasoning and real-world understanding.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

Rod

  • Guest
Re: MOSAiC news
« Reply #954 on: August 09, 2020, 09:15:00 PM »
Sorry too, oren.  I was being sarcastic because there were some pretty crazy things in the original post.

Now that it is being modified, I will delete my comment.

oren

  • Moderator
  • First-year ice
  • Posts: 6192
    • View Profile
  • Liked: 2252
  • Likes Given: 1890
Re: MOSAiC news
« Reply #955 on: August 09, 2020, 09:23:21 PM »
No need to delete, just find me a good thread to move it all to.
I did not snip the original comment as I often don't have enough confident knowledge to delete things directly. So thanks for the rebuttals.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #956 on: August 10, 2020, 04:23:00 PM »
drift update, mosaic Pbuoys, jul1-aug10.
« Last Edit: August 10, 2020, 04:32:50 PM by uniquorn »

OffTheGrid

  • New ice
  • Posts: 58
    • View Profile
  • Liked: 31
  • Likes Given: 31
Re: MOSAiC news
« Reply #957 on: August 10, 2020, 11:02:34 PM »
I agree basal ice streams  mechanisms are ot here. The paper I read on bedrock melting due to the friction of stop start  ice streams in Antarctica was some twelve years ago. If binntho wants to learn on an appropriate thread what a layer of entrained boulders can do as it gouges his grooves in the bedrock when under the pressure of kilometers of ice and downstream elastic tensions are suddenly released, I am surprised he is so certain that such heat released by this friction can't melt rock. But will try to find the paper and post it there. The flash refreeze physics are what startled me.
More on topic..
The only submarine landslide down a canyons system caught in the act of a flush wave and the results studied:
"The tsunami following the 2016 Kaikoura earthquake was relatively small but it was still the most significant event in around 50 years. Being onsite at the time and in the following months, we were able to document changes to the seabed and it has revealed some exciting science,” Dr Mountjoy said.

“In January 2017, we surveyed down to 2000m and discovered that large areas of the Kaikoura Canyon have drastically changed. Sediment has been transported from the Kaikoura canyon at least 300km north to the deep ocean floor offshore Wairarapa. The earthquake shook loose a huge amount of mud from the canyon rim that then flowed down into the canyon channel. As it accelerated downslope, this material appears to have eroded deeply into the canyon floor and ignited into a critical condition we call ‘autosuspension’. Amazingly, in this condition, sediment can flow indefinitely across the ocean floor. We know the deep sea Hikurangi Channel is 1500km long and this flow may have travelled the full length of it. No one has ever directly observed this process before – it is an amazing opportunity.”
This relatively small event moved "well over 850 million tons" of subglacial debris from the south zelandian ice sheet collapse over 10ky bp down a two to five km wide canyon carving 20 to 50m extra depth in the bedrock channel.
Zelandia is very simular to Greenland after deglaciation, and this is probably the smallest of three primary submarine  canyons. All carved by Jökulhlaup as can be see bursting on a daily basis on worldview from Greenland.
As this one was triggered by a paltry few thousands tons of river sediment shaken off the top of shelf above canyon head, I cannot imagine this not being an ongoing process in the arctic daily, and larger, at present.
Deserves Its own thread too. But for those interested:
https://niwa.co.nz/news/kaikoura-earthquake-provides-world-first-insight-into-submarine-canyons

https://niwa.co.nz/news/kaikoura-earthquake-generated-huge-submarine-sediment-shift

https://niwa.co.nz/news/a-wave-of-hazard-research

Note the rubble sizes transported in hypersuspension hundreds of km, and the many canyon systems visible on bathometry that is much higher resolution than any publicly available for the arctic. Kaikoura is noticably not the originator of this canyon system, but pegasus off the previously ice covered submerged land to the southeast where perhaps six major outbursts channels can be seen from previous deglaciations.
Greenland Zelandia and west Antarctica are very simular continents, in different geologic periods due to current latitude and climate.
Click on bottom two files for before/ after shelf image of initiating landslide and animated zoom in on the 2500km extention of the glacial rubble carved channel out to the Louisville seamount chain.

« Last Edit: August 11, 2020, 12:16:20 PM by OffTheGrid »

NotaDenier

  • New ice
  • Posts: 99
    • View Profile
  • Liked: 43
  • Likes Given: 28
Re: MOSAiC news
« Reply #958 on: August 11, 2020, 01:50:05 AM »
https://www.theatlantic.com/science/archive/2020/08/an-arctic-scientists-dizzying-journey-home-during-the-coronavirus/615124/

One scientist started in the Arctic Ocean and ended up crossing the Russia-Finland border on a folding bicycle procured in Germany.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #959 on: August 11, 2020, 10:22:36 PM »
good image of melt ponds, ridging, low freeboard, fractures on fomo today

oren

  • Moderator
  • First-year ice
  • Posts: 6192
    • View Profile
  • Liked: 2252
  • Likes Given: 1890
Re: MOSAiC news
« Reply #960 on: August 11, 2020, 11:44:30 PM »
Great image. Just noting the location for reference: approximately 80N, 6W, Fram Strait, at the very top of the Greenland Sea.

blumenkraft

  • Guest
Re: MOSAiC news
« Reply #961 on: August 13, 2020, 12:38:13 PM »
On thin ice: The Arctic and earth's climate

Quote
The Arctic plays an important role in the earth’s climate, but our knowledge about the winter there is limited. The polar region is changing. The sea ice has been shrinking for decades. Why is that? We search for answers in the far north.

Link >> https://www.dw.com/en/on-thin-ice-the-arctic-and-earths-climate/av-54478978

Very nice video at link.

OffTheGrid

  • New ice
  • Posts: 58
    • View Profile
  • Liked: 31
  • Likes Given: 31
Re: MOSAiC news
« Reply #962 on: August 13, 2020, 09:32:45 PM »
Should be in helicopter range. Apologies for understated dark humour about "dramatic". Had no Idea at the time.:
https://forum.arctic-sea-ice.net/index.php/topic,400.msg280842.html#msg280842

blumenkraft

  • Guest
Re: MOSAiC news
« Reply #963 on: August 14, 2020, 09:40:42 PM »
From the MOSAIC web app:

Quote
We are making good progress on our way northwards and have
traveled roughly 150 nm (about 277 kilometers) in the first 24
hours after we left our mooring position yesterday. This morning
we had nearly open waters around the ship as we are in the SO-
called northeastern Greenland polynya: an area of open water,
which is driven by offshore winds pushing the sea ice away from
land. At the moment, the ice concentration north of Greenland is
quite loose compared to areas further east. That's why we decided
to steam more or less directly to the North, using low ice
concentrations as long as possible before we turn eastwards and
look for an ice floe that has properties comparable to the original
MOSAiC floe.

blumenkraft

  • Guest
Re: MOSAiC news
« Reply #964 on: August 15, 2020, 06:11:44 PM »
On our way north, we are now in colder waters ( colder than 1.4˚C) again (marked area). Before it was warmer than -1˚C. Click to enlarge.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #965 on: August 15, 2020, 08:24:29 PM »
polarview S1 from 11:09UTC, white pixel close to PS location.
jp2 close up.
2020-Aug-15 11:00   N 85°06' W 015°36' (from sailwx)

Making good headway up to now in the relatively open water.

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #966 on: August 15, 2020, 08:46:03 PM »
Very fortunate to having a well-appointed research vessel enter the baffling area of ice decay between Greenland and the North Pole.

It's not at all clear what the final destination is though the publicist writing 'Follow' suggests it is out of satellite range which for Sentinel-1AB is 87.5ºN (WorldView satellites don't have a pole hole but clouds often preclude imaging). The PS is moving rapidly, a full degree of latitude north in the last 12 hours (111 km by 20-08-15 19:00 ) plus 2º of longitude west.

They're fixing the helicopters but may or may not share those photos (or much else en route). The bow radar is no longer reporting at 6 hrs frequency, having stopped on Aug 9th. If restarted upon mooring, it would benefit from synchronous overhead views and shipboard commentary.

https://data.meereisportal.de/maps/animations/Iceradar/?C=M;O=D

Let's hope the PS focuses on the current melt season rather than searching for another meaningless ice jumble. (N-ICE2015 already followed four of them to oblivion.)

The PS reached the rarely studied Wandel Sea a couple years back after a strong narrow cyclone blew up the Fram, pushing the ice well north of the flux gate. The captain toyed with the safety of continuing through the Lincoln Sea and around Greenland via the Nares. The PI wrote me that the ship is equipped to do CTD tests on its own and did so (but the data could not yet be shared).

Fram export winds ceased in mid-May, not displaying a consistent pattern since. Despite the lack of a dramatic storm in the Straits this season, the 'cumulative impact' of moderate but generally non-northerly winds could possibly explain both the lift-off from the CAA, churning of Lincoln Sea ice, and the remarkable deterioration towards the Pole.

Since the ice has not been notably pushed, southerly winds would have needed to bring some mix of sunshine, warm air and overturned warm water acting on dodgier-than-realized ice.  Morris Jesup is not favorably located for katabatic winds off the Greenland summit ridge. No one here has systematically examined online daily records of the automatic weather station there.

This same 'Follow' publicist wrote in a double falsehood yesterday that the ship had passed through the offshore wind-created Northeast Water polynya. The facts and location concerning  that water opening have been established from 90 years of arduous on-site field work, beginning with Lauge Koch in 1933.

Read about it here:

http://www.issibern.ch/teams/Polynya/

https://sci-hub.se/10.1007/bf00240265

https://www.tandfonline.com/doi/abs/10.1080/00167223.2010.10669503?journalCode=rdgs20

https://www.researchgate.net/publication/226224526_The_Northeast_Water_polynya_Greenland_Sea

The Sentinel-1B below was colored by embedding a small fiducial black square, setting the colorpicker after some trial and error to radius 5, and clicking to find black elsewhere in the image. The selection was then filled with 'open water blue' though parts may have small floes or be half-slush.
« Last Edit: August 15, 2020, 10:11:58 PM by A-Team »

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #967 on: August 15, 2020, 10:35:33 PM »
Airborn Expendable Ice Buoy (AXIB)
Quote
An Air-Deployable Expendable Ice Buoy (AXIB) that can withstand multiple freeze-thaw cycles and operate equally well in ice prone ocean or fresh water. The AXIB can be dropped from an airborne platform, land on an ice surface, right itself to the vertical position, anchor and stabilize itself in the ice, withstand several freeze-thaw cycles and continue to transmit data while anchored to the ice or floating in the ocean. The unique hull design of the AXIB allows it to withstand multiple freeze-thaw cycles and continue to function. The AXIB is particularly well suited for deployment and utilization in any ice zone where repeated freeze-thaw cycles occur.

iabp buoy 300234065497190, north of Greenland. Drift speed and air temperature. Surface temperature and pressure are also available.
« Last Edit: August 15, 2020, 10:44:42 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #968 on: August 16, 2020, 04:43:34 AM »
Very nice, to have supplemental sturdy buoys dropped by airplane out of say Alert.

Some 33 AIXB have been deployed in recent years; 7 are still active but only 3 of those are high latitude Arctic Ocean:

145951                   2016   AXIB  Healy     86.88  -70.47
300234065497190   2018   AXIB  USIABP   86.41  -44.70
300234065498190   2018   AXIB  USIABP   86.65  -157.31


The hardware graphic above has a bad typo "mast parachute bridal stays (3)" that throws google search off. These are properly called bridle stays, as for a horse.

The animation looks to be 640 frames at 6-hr intervals starting on March 30th and ending for now at 19:00 on August 11th. After rotating and rescaling, the buoy track is shown over AMSR2 along with the nearby Polarstern position (red in yellow star) at 09:00 today, 85.0  -15.0. (It's now at 86.0  -18.4 20-08-16 00:00 some 111 km farther north.)

It's best with so many frames to NOT de-optimize the gif but rather 'make new layer from visible' in Gimp. Then copy and start a new image with this frame. The needed rotation can be deduced using the -60º longitude line through the Nares. Scaling can be done rapidly by over-shooting, undo, under-shooting until convergence of the main latitude line. The palette and text metadata should be cut out early on and made into separate layers so they are not affected by map rotation. In gimp, a layer should be expanded using 'layer to image size' before rotating less parts get lost.
« Last Edit: August 16, 2020, 05:00:42 AM by A-Team »

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #969 on: August 16, 2020, 02:35:20 PM »
Quote
It's best with so many frames to NOT de-optimize the gif
For the full path from the final frame, can also save export as png or jpg

A closer look at iabp buoy 300234065497190, north of Greenland. Drift speed, rough lat/lon and air temperature. There would appear to be some small tidal movement in this area also.
« Last Edit: August 16, 2020, 04:35:55 PM by uniquorn »

Phil.

  • Frazil ice
  • Posts: 362
    • View Profile
  • Liked: 45
  • Likes Given: 1
Re: MOSAiC news
« Reply #970 on: August 16, 2020, 02:41:01 PM »
This gives an error for me won't run.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #971 on: August 16, 2020, 03:23:38 PM »
hmm, if you refer to the gif on #969, it runs in firefox, chrome and edge on windows.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #972 on: August 16, 2020, 05:53:21 PM »
iabp buoy 300234065497190, overlaid onto noaa bathymetry

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #973 on: August 16, 2020, 06:55:51 PM »
Quote
gif won't run
Hmm, works on Opera, Chrome, Safari and Firefox on iMac and Safari on iPhone.

The PS is making incredible headway both north and west almost to the head of the opening above Greenland, halfway to the north pole itself.

Evidently they don't want to moor in that TransPolar Drift again but instead seize a very rare opportunity to access the central CAB. (No information is being furnished today by 'Follow'.)

The PS just turned the bow radar back on two quite interesting frames show the ice ahead. There's a lot of open water.

Meereis portal has an excellent melt article posted on the 14th describing melt ponds and ice thickness measurements. They've posted a Sentinel-2 time series (ie in the visible) which we've not used here to date.
Quote
We recorded a gradual decrease in the average ice thickness: a drop of approximately one metre over the course of July. At the same time, pond depths began increasing, until the first holes appeared in the melt ponds through which the meltwater poured into the ocean below. In some ponds, we recorded spectacular depths of more than 150 cm...

We used the ablation stake to measure the position of the snow and ice surfaces and the hotwire to measure the position of the ice bottom. We measured an average of ~85cm of ice thinning across our stakes sites from 26 June to 30 July. Surface ablation accounted for 75% of that thinning, while bottom melting made up the remaining 25%....

Especially the deep keels that extended more than 8 m into the comparably “warm” ocean were eroding quickly. In some parts of the ridged ice, keel depth decreased by up to 2 m in just the first 14 days..

Over 30 digital thermistor chains were deployed across MOSAiC’s Central Observatory, which allowed us to monitor the hourly temperature evolution in different ice and snow layers though the data is still being processed,
 
In the end, the decreasing thickness, pre-existing weaknesses, and numerous thaw holes in melt ponds made the floe unstable and less able to withstand ocean swell and collisions with surrounding floes.
https://www.meereisportal.de/en/mosaic/sea-ice-ticker/
https://data.meereisportal.de/maps/animations/Iceradar/?C=M;O=D

The image and slide shows below need a click to play or display properly.
« Last Edit: August 16, 2020, 08:38:08 PM by A-Team »

HapHazard

  • Frazil ice
  • Posts: 356
    • View Profile
  • Liked: 141
  • Likes Given: 2631
Re: MOSAiC news
« Reply #974 on: August 16, 2020, 07:58:44 PM »

The PS is making incredible headway both north and west almost to the head of the opening above Greenland, halfway to the north pole itself.

Evidently they don't want to moor in that TransPolar Drift again but instead seize a very rare opportunity to access the central CAB.

This is a very interesting sojourn. I'm grateful for this opportunity to glean info about what's going on here. Thanks for your posts.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #975 on: August 16, 2020, 09:08:09 PM »
Polarstern relative to 97190

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #976 on: August 16, 2020, 09:19:40 PM »
From the mosaic ticker

Quote
Digital thermistor chains (Fig. 3) are another essential tool for measuring changes in ice and snow thickness over time. Over 30 of these units were deployed across MOSAiC’s Central Observatory, which allowed us to monitor the hourly temperature evolution in different ice and snow layers spread out around the floe. Though the data is still being processed, the legs of the DTC unit in the photo (Fig. 4) illustrate the progressive ice surface melting: the tops of the white tubes were initially installed level with the ice surface.

Hourly measurements, possibly requiring regular battery changes. Looks different to the Tbuoy set up.
« Last Edit: August 16, 2020, 09:31:16 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #977 on: August 16, 2020, 09:45:28 PM »
Last looks at the ice the Polarstern is traversing, soon it will be in the Sentinel-1AB pole hole. It's already off the PolarView imagery for the day (last image, needs click). We'll still have a view but it will be nearly horizontal (bow radar).

Might the Polarstern stop to download data from buoy 97190 or change its batteries? No, already far to the north. However the PS might launch a set of its own new buoys on this leg to over-winter in the CAB.

https://www.polarview.aq/arctic only held 30 days
« Last Edit: August 16, 2020, 09:57:00 PM by A-Team »

Phil.

  • Frazil ice
  • Posts: 362
    • View Profile
  • Liked: 45
  • Likes Given: 1
Re: MOSAiC news
« Reply #978 on: August 17, 2020, 04:38:28 AM »
hmm, if you refer to the gif on #969, it runs in firefox, chrome and edge on windows.

It works now, wouldn't this morning for some reason.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #979 on: August 17, 2020, 09:47:31 AM »
87N to 88N in 14 hours. Ice must be weak in that area.

jdallen

  • Young ice
  • Posts: 3233
    • View Profile
  • Liked: 499
  • Likes Given: 204
Re: MOSAiC news
« Reply #980 on: August 17, 2020, 10:00:22 PM »
87N to 88N in 14 hours. Ice must be weak in that area.
Polarstern is moving through ice at the equivalent of a decent jog (about 8 kph).  Rather alarming, actually.
This space for Rent.

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #981 on: August 17, 2020, 10:22:16 PM »
sailwx hourly data for PS
edit: This is a first attempt to merge iabp and sailwx data (in different format) so should only be taken as a guide)
« Last Edit: August 18, 2020, 10:10:57 AM by uniquorn »

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #982 on: August 17, 2020, 11:20:23 PM »
Quote
8 kph. Rather alarming, actually
Indeed. Even for an icebreaker rated at 2m, it's surprising to see them plow straight ahead. They must not see a reason to take whatever ice is  in their path very seriously. It must be a mixture of thin ice and open water like AMRS2 is showing. The last bow radar snapshot shows floes and weak matrix above 87º. It's not clear whether they are looking for SYI or older CAB ice.

They are ~100 km into the Sentinel-1AB pole hole and WorldView is clouded over. Let's hope they share some helicopter imagery after mooring.

It appears now like the PS has slowed down to look at the suitability of individual floes for study. The ship has gone so far west that there is almost no possibility of further TransPolar Drift. The last thing they want is to be swept into the Fram again.

If the PS wants to reach the North Pole itself, the going could get tougher. The scientific justification for that isn't clear. They went to study freeze-up to mid-October but what is being learned about the end of this extraordinary melt season may be more important. There is no real likelihood of being hopelessly frozen in, though depending on winds, the ice could close in.

glennbuck

  • Frazil ice
  • Posts: 334
    • View Profile
  • Liked: 114
  • Likes Given: 30
Re: MOSAiC news
« Reply #983 on: August 17, 2020, 11:43:20 PM »
87N to 88N in 14 hours. Ice must be weak in that area.
Polarstern is moving through ice at the equivalent of a decent jog (about 8 kph).  Rather alarming, actually.

 Polarstern can break through ice 1.5 m (4 ft 11 in) thick at a speed of 5 knots (9.3 km/h; 5.8 mph).

https://en.wikipedia.org/wiki/RV_Polarstern

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #984 on: August 18, 2020, 11:25:52 AM »
The Polarstern is continuing to move towards (or past, to original lat,lon?) the North Pole this morning, having covered almost a degree of latitude (111 km) in the last 24 hours with a similar distance to go.

https://www.movable-type.co.uk/scripts/latlong.html  for converting lat lon pairs to km

Update 3: the PS has moved significantly poleward and set out its first buoy! (No tracking number was provided; minimally, it has GPS and air pressure reporting. Ice thickness was measured but not shared; lots of melt ponds are visible at 89º.)

90.0  -20.0 20-08-19 10:00    3  170     -0.3
89.3  -36.9 20-08-18 22:00    4  230     -0.7
89.1  -35.6 20-08-18 15:00    5  260      0.7

Lat  Long  YY-MM-DD  UTC     Wind       T(C)
88.9  -35.7 20-08-18 07:00    5   60      1.0
88.0  -39.4 20-08-17 07:00    5   30     -0.1


How fast it can move through pack ice depends very much on the thickness of that ice, its melt state, age, mechanical strength and compaction pressure from the sides. While they log ice condition on the fly, it is not shared in nrt other than via the 6-hr bow radar. (On leg 3 for example, a scientist set up a forward-facing iphone on time lapse and once back on shore could put it on twitter. The ship can be seen ramming the ice back and forth at certain times.

We discovered early on that ImageJ (but not Gimp) can open the bow radar .avi format instantly to grayscale frames, giving full control over cropping, contrast change, playback speed, frame retention, re-export to avi, and final conversion to mp4 since forum software only supports avi as non-displaying attachment. Those operations would be much harder or not doable at all for a mp4.

In summary, PS is not currently moored to a new floe but bow radar near-horizontal snapshots of the ice ahead are posted through midnight of Aug 17th. The big question is how mobile the ice pack will be at the final destination. Bow radar is very good at displaying that. They don't want to deploy a lot of expensive and irreplaceable equipment out on an unstable floe.

The no-data pole hole of AMSR2_AWI is at 89.2º, the same as before. For now, the ice concentration at the ship's location can still be seen but just barely. The weather at this location is unremarkable. Fram export has picked up but the Polarstern will not be caught up in it.
Quote
DriftStories – 06: Snow, the great unknown

The number of winter days on which snow falls in the Central Arctic can be counted on one hand. Nevertheless, the amount of snow on the Arctic sea ice is a key factor influencing how quickly the ice grows, and when it begins melting in the spring. But until recently, little has been known about this enigmatic white substance. AWI sea-ice physicists have developed and implemented a unique snow research program...

... when it comes to local snow accumulation on the Arctic sea ice, snow drifts appear to play a far more important role than total precipitation. “Because of the strong winds, fresh snow doesn’t simply stay where it fell. It is transported and accumulates in large mounds on the ice surface, for example in the lea of pressure ridges,” says Daniela Krampe.

The AWI researchers’ observations have since been confirmed by data from the 14 snow buoys that the team had installed on level ice at the beginning of the expedition. While the snow layer on the level ice increased only gradually, and was still nowhere near the 30-centimetre mark by the end of the winter, behind the ridges the researchers soon found themselves hip-deep in snow.
https://www.meereisportal.de/en/mosaic/driftstories/driftstories-06-snow-the-great-unknown/
https://data.meereisportal.de/maps/animations/Iceradar/?C=M;O=D
https://www.awi.de/fileadmin/user_upload/MET/PolarsternCoursePlot/psobsedat.html
« Last Edit: August 19, 2020, 01:28:38 PM by A-Team »

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #985 on: August 18, 2020, 12:34:51 PM »
There is an occasional entry for ice state on the MET file with description of the codes
latest was 58/98
ci -- Concentration or arrangement of sea ice
5 -- Very close pack ice 7/8 to < 8/8 concentration
Si -- Stage of development
8 -- Predominantly medium and thick first-year ice with some old ice (usually more than 2 meters thick)
bi -- Ice of land origin
 / -- Unable to report, because of darkness, poor visibility or only sea ice is visible
Di -- Bearing of principal ice edge
9 -- Not determined (ship in ice)
zi -- Ice situation and trend over preceding 3 hours
 8 -- Ice under moderate or severe pressure

Quote
Ice Information: ci Si bi Di zi

ci -- Concentration or arrangement of sea ice

    0 -- No ice
    1 -- Ship in open lead more than 1 n. mile wide or ship in fast ice with boundary beyond limit of visibility
    2 - 5 Ice concentration uniform
    2 -- Open water or very open pack ice, < 3/8 concentration
    3 -- Open pack ice 3/8 to < 6/8 concentration
    4 -- Close pack ice 6/8 to < 7/8 concentration
    5 -- Very close pack ice 7/8 to < 8/8 concentration
    6 - 9 Sea ice concentration not uniform
    6 -- Strips and patches of pack ice with open water between
    7 -- Strips and patches of close or very close pack ice with areas of lesser concentration between
    8 -- Fast ice with open water, very open or open pack ice to seaward of the ice boundary
    9 -- Fast ice with close or very close pack ice to seaward of the ice boundary
    / -- Unable to report, because of darkness, poor visibility or because ship is more than 0.5 n. mile away from ice edge

Si -- Stage of development

    0 -- New ice only (frazil ice, grease ice, slush, shuga)
    1 -- Nilas or ice rind, < 10 cm thick
    2 -- Young ice (grey ice, grey-white ice) 10-30 cm thick
    3 -- Predominantly new and/or young ice with some first-year ice
    4 -- Predominantly thin first-year ice with some new and/or young ice
    5 -- All thin first-year ice (30-70 cm thick)
    6 -- Predominantly medium first-year ice (70-120 cm thick) and thick first-year ice (>120 cm thick) and some thinner (younger) first-year ice
    7 -- All medium and thick first-year ice
    8 -- Predominantly medium and thick first-year ice with some old ice (usually more than 2 meters thick)
    9 -- Predominantly old ice
    / -- Unable to report, because of darkness, poor visibility or only ice of land origin visible or because ship is more than 0.5 n. mile away from ice edge

bi -- Ice of land origin

    0 -- No ice of land origin
    1 -- 1-5 icebergs, no growlers or bergy bits
    2 -- 6-10 icebergs, no growlers or bergy bits
    3 -- 11-20 icebergs, no growlers or bergy bits
    4 -- Up to and including 10 growlers and bergy bits - no icebergs
    5 -- More than 10 growlers and bergy bits - no icebergs
    6 -- 1-5 icebergs with growlers and bergy bits
    7 -- 6-10 icebergs with growlers and bergy bits
    8 -- 11-20 icebergs with growlers and bergy bits
    9 -- More than 20 icebergs with growlers and bergy bits - a major hazard to navigation
    / -- Unable to report, because of darkness, poor visibility or only sea ice is visible

Di -- Bearing of principal ice edge

    0 -- Ship in shore or flat lead
    1 -- Ice edge towards NE
    2 -- Ice edge towards East
    3 -- Ice edge towards SE
    4 -- Ice edge towards South
    5 -- Ice edge towards SW
    6 -- Ice edge towards West
    7 -- Ice edge towards NW
    8 -- Ice edge towards North
    9 -- Not determined (ship in ice)
    / -- Unable to report, because of darkness, poor visibility or only ice of land origin is visible

zi -- Ice situation and trend over preceding 3 hours

    0 -- Ship in open water with floating ice in sight
    1 -- Ship in easily penetrable ice; conditions improving
    2 -- Ship in easily penetrable ice; conditions not changing
    3 -- Ship in easily penetrable ice; conditions worsening
    4 -- Ship in ice difficult to penetrate; conditions improving
    5 -- Ship in ice difficult to penetrate; conditions not changing
    6 - 9 Ice difficult to penetrate; conditions worsening
    6 -- Ice forming and freezing together
    7 -- Ice under slight pressure
    8 -- Ice under moderate or severe pressure
    9 -- Ship beset
    / -- Unable to report, because of darkness, poor visibility
Quote
  Lat  Long  YY-MM-DD  UTC     Wind       T(C)  N  h  VV  wwWW  ICE  Pnn(hPa)
  88.9  -35.9 20-08-18 09:00    5   60      0.9  7  5  98  0222 58/98 1024.1
  88.9  -35.8 20-08-18 08:00    5   60      0.8  /  /  //     ////    ///// 1024.1
  88.9  -35.7 20-08-18 07:00    5   60      1.0  /  /  //     ////    ///// 1023.9
  88.9  -35.6 20-08-18 06:00    5   60      1.0  7  5  99  4022 58/98 1024.1
  88.9  -35.4 20-08-18 05:00    4   60      1.7  /  /  //     ////    ///// 1023.8

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #986 on: August 18, 2020, 12:44:12 PM »
interesting that they don't show water temperature on that MET page. They do report weather conditions so we could see when first snow falls.

Quite 'warm' at -1.4C (from sailwx)

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #987 on: August 18, 2020, 10:54:06 PM »
buoy on a boat

be cause

  • Nilas ice
  • Posts: 1379
    • View Profile
  • Liked: 597
  • Likes Given: 455
Re: MOSAiC news
« Reply #988 on: August 18, 2020, 11:05:32 PM »
the buoys on the boat don't seem to be meeting much resistance as they head north .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 
 (phew)

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #989 on: August 18, 2020, 11:37:36 PM »
Nice video on platelets, ice crystals and ice thickening featuring the ROV
https://www.dw.com/en/on-thin-ice-the-arctic-and-earths-climate/av-54478978

uniquorn

  • Young ice
  • Posts: 2673
    • View Profile
  • Liked: 1193
  • Likes Given: 232
Re: MOSAiC news
« Reply #990 on: August 19, 2020, 12:01:47 PM »
Last reported at 2020-Aug-19 09:00 UTC. Time now 2020-Aug-19 09:58 UTC.
Position N 89°54' W 035°30'.
Ice state from awi met still 58/98

edit:
Last reported at 2020-Aug-19 10:00 UTC. Time now 2020-Aug-19 10:51 UTC.
Position N 90°00' W 020°00'.
« Last Edit: August 19, 2020, 12:52:12 PM by uniquorn »

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #991 on: August 19, 2020, 06:18:42 PM »
They've arrived at the North Pole after making a smart decision to steam up through the unusual low concentratio ice north of Greenland. The ice is just one melt pond after another there. The Polarstern appears to be looking around for a suitable study floe as longitudes are varying wildly about the pole.

WorldView is currently cloudy; Sentinel-1AB and AMSR2 don't get up this far; Mosaic rarely releases any imagery of scientific interest. So the only sources of information on ice condition will come from awiMet and bow radar. The latter's last frame is 18:00 on the 18th when the PS was at 89.16º.
   
   Lat  Long  YY-MM-DD  UTC     Wind       T(C)  N  h  VV  wwWW  ICE  Pnn(hPa)
  90.0  132.3 20-08-19 15:00    3  360     -0.7  7  3  98  0222 58/98 1023.3
  90.0  147.7 20-08-19 12:00    5  150     -0.5  8  2  98  2054 58/98 1023.9
  90.0  115.6 20-08-19 11:00    3  200     -0.4  /  /  //  //// ///// 1023.9
  90.0  -20.0 20-08-19 10:00    3  170     -0.3  /  /  //  //// ///// 1024.0
« Last Edit: August 19, 2020, 06:26:04 PM by A-Team »

marcel_g

  • Frazil ice
  • Posts: 126
    • View Profile
    • Art by Marcel Guldemond
  • Liked: 55
  • Likes Given: 362
Re: MOSAiC news
« Reply #992 on: August 19, 2020, 06:24:50 PM »
They've arrived at the North Pole after making a smart decision to steam up through the unusual low concentratio ice north of Greenland. The ice is just one melt pond after another there. The Polarstern appears to be looking around for a suitable study floe as longitudes are varying wildly about the pole.
  <snip>

Is that a photo of what it looks like at the NP? Doesn't look like any of that ice is suitable. Wow.

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #993 on: August 19, 2020, 07:09:08 PM »
Quote
is that at the Northj Pole?
Yes, the photo is cropped from one with leaders holding up a plaque celebrating the PS arrival at 90º. The water depth at the North Pole has been measured by Russians at 4,261 m (13,980 ft); the scientific crew here sampled bottom water and passed around souvenirs.

The two-frame slide show shows ice conditions according to the most recent AMSR2_AWI. A lot of the ice near the Pole (in the direction of Greenland) is in the 80-95% concentration range, thus measurably off solid. That doesn't include ponds that haven't melted all the way through yet.

They are looking for ice stable enough to melt to set up a somewhat dispersed observatory to get away from ship-generated artifacts yet not get into all the problems of before with power and data cables, retrievability and safety. Better ice can be found along the 180º meridian, say 100 km in the direction of Wrangel.

No thickness or ice temperature profile data has been shared though teams have already cored through and helicopters have done em-bird mapping rasters. Thickness alone doesn't suffice as the bottom can be coated with algae and even scrape off. More information may be gleaned from new buoys but that takes time to find when the IMEI or Mosaic identification numbers aren't disclosed; close-in buoys may report over closed circuit rather than Iridium.

The buoy launched a couple days back is not listed under its launch date on the list of all active buoys. However it appears that buoys launched in 2019, retrieved from the Fram, and re-launched at high latitude still retain their 2019 launch date in the unsortable table. By keyword searching for 89., 88., etc the five highest-latitude Mosaic buoys can be located, including three snow buoys at 89º.

https://data.seaiceportal.de/gallery/index_new.php?active-tab1=mosaic&region=n&expedition=MOSAiC&buoytype=all&buoystate=active&buoynode=all&submit3=display&lang=en_US&active-tab2=buoymosaic
« Last Edit: August 19, 2020, 09:18:34 PM by A-Team »

HapHazard

  • Frazil ice
  • Posts: 356
    • View Profile
  • Liked: 141
  • Likes Given: 2631
Re: MOSAiC news
« Reply #994 on: August 19, 2020, 08:38:27 PM »
Pic taken at the Pole. Lovely ice conditions, eh?


Glen Koehler

  • Frazil ice
  • Posts: 335
    • View Profile
  • Liked: 329
  • Likes Given: 732
Re: MOSAiC news
« Reply #995 on: August 19, 2020, 08:48:21 PM »
    Great picture.  Looks like a mix of melt ponds and open water.  Correct?  Any estimate of thickness of the ice in the picture? (it looks very thin, ca. 0.25 meter?). 
« Last Edit: August 19, 2020, 09:05:05 PM by Glen Koehler »

glennbuck

  • Frazil ice
  • Posts: 334
    • View Profile
  • Liked: 114
  • Likes Given: 30
Re: MOSAiC news
« Reply #996 on: August 19, 2020, 09:36:10 PM »
    Great picture.  Looks like a mix of melt ponds and open water.  Correct?  Any estimate of thickness of the ice in the picture? (it looks very thin, ca. 0.25 meter?).

Not sure but found past north pole ice thickness in this report.

Initial measurements of the ice thickness confirm this: in 2011 as well as in 2007 the most frequently occurring ice thickness was 0.9 metres. As a comparison, the most frequently measured ice thickness in 2001 was around 2 metres. In that year the extent of the ice cover at the end of the melting period corresponded roughly to the long-term mean.

(wattsupwiththat) /2011/08/23/icebreaker-at-the-north-pole/

<WUWT is a denier site and is not considered a reliable source. I refuse to click such links myself so cannot check what this is based on, but if you can find another source for this info it would be better. O>
« Last Edit: August 21, 2020, 11:41:34 AM by oren »

A-Team

  • Young ice
  • Posts: 2662
    • View Profile
  • Liked: 555
  • Likes Given: 30
Re: MOSAiC news
« Reply #997 on: August 19, 2020, 09:40:25 PM »
Quote
are these photos for real? how thick is the ice at the North Pole?
Yes, so far all the photos posted show the immediate area of the North Pole, not the usual Greenland icebergs or Antarctic penguins. It's astonishing to see it all extending out to the horizon, who knew?. The pole areas out to ~200 km are very difficult to observe because most satellites need to be in near-polar orbit and require fairly narrow swaths to have any resolution (or work in the visible and can't see through the clouds).

Mosaic does have some bad photo practices such as wiping Exif data including GIS, using unstated 'shipboard time' instead of UTC, showing date blogged instead of the photo timestamp, and not flattening the key data irreversibly onto the photo jpg file where it cannot be lost, forged or removed except by cropping. (Even the cheapest flip-phone will do all this.)

The first and fourth photos below from the press release shows freeboard and submerged ice a little more clearly; the ratio should be 1:9, but how do we calibrate an absolute scale? Note melt ponds are easily distinguished from 'leads' which are a mixture of leads and icebreaker paths. I don't see a floe suitable for six weeks of mooring but they have been looking around at the pole for 9 hours so far.

We've also located incoming data for the three new snow buoys re-launched at 89º in #993. I'll defer to Uniquorn on proper reading of buoy data for S93 but the green seems to be thickness and as marked by a little box on the y-axis, seems to be at 0.22 m below sea level. Live links to the data are provided above.

Mosaic is stating repeatedly that the NP is in the center of the TPD. This is false. The pole has rarely been included over the last ten years in the TransPolar Drift, better named the CircumPolar Drift as it primarily sweeps around from the Laptev to Frame about halfway to the SZ FJL SV line. This year though, the drift took in an extraordinary swath of Arctic Ocean including areas even beyond the pole. It's all been documented repeatedly on enhanced Ascat time series -- it's futile to argue with unambiguous satellite data but people still do.

The other take-away from these shocking pole photos: these melt ponds may be deepening and even draining but they are not new. Suppose half of the surface area shown has been ponded or open water since mid-July, the whole way up from Greenland. This means the albedo has been very low compared to snow on ice during the high insolation levels. In turn this means fractional BOE is already upon us in terms of not reflecting excess solar energy back to space regardless of how the next two months play out.

Melt ponds + leads take up 51% of the pixels in the photo after excision of the Polarstern; there is slant bias favoring the foreground but an overhead ratio may well be similar.

Quote
PI Markus Rex: “Up until 87.5ºN, for the most part we passed through open water, in some cases stretching to the horizon. Based on the satellite imagery, we weren’t sure whether the loose ice cover was due to wind and currents, and were concerned a change in weather conditions could compact it again. Once in the region, however, they found that much of the sea ice truly had melted away, and hadn’t simply been broken up by the wind.

Captain Wunderlich: “I’m very surprised to see how soft and easy to traverse the ice up to 88° North is this year, having thawed to the point of being thin and porous. Even after passing 88° North we mostly maintained a speed of 5-7 knots; I’ve never seen that so far north...Normally  it’s home to thicker and older ice and virtually impassable. But now we’re finding extended stretches of open water reaching nearly to the Pole.

Moving on from the Pole, the Polarstern may follow the Transpolar Drift a bit further (i.e. towards Siberia) until she reaches ~87° North. “Depending on the ice conditions, however, we’ll also start looking for a suitable floe in the vicinity of the North Pole.

Rex was quoted in a single news story as saying this -- all the other newspapers cropped it out:

“It's frightening to see how thin the sea ice is and how quickly it is melting. Something needs to be done urgently. The Arctic cannot wait long."

https://www.tellerreport.com/news/2020-08-19-little-sea-ice--"polarstern"-reaches-the-north-pole-faster-than-expected.Bkfeon39Gw.html
« Last Edit: August 19, 2020, 11:42:10 PM by A-Team »

marcel_g

  • Frazil ice
  • Posts: 126
    • View Profile
    • Art by Marcel Guldemond
  • Liked: 55
  • Likes Given: 362
Re: MOSAiC news
« Reply #998 on: August 19, 2020, 10:27:34 PM »
The other take-away from these shocking pole photos: these melt ponds may be deepening and even draining but they are not new. Suppose half the area shown has been ponded or open water since mid-July insolation levels. This means the albedo has been very low compared to snow on ice. In turn this means fractional BOE is already upon us, regardless of how the next two months play out.

I like that term 'fractional BOE' and how it makes me think about the system. The changes to the key things about the Arctic Sea Ice - reducing solar energy accumulation (albedo) and keeping global weather patterns normal - are not either/or changes, and they will not stay the same before BOE and then 'flip over' when BOE happens. They will shift on a gradient, and that gradient can be expressed as Fractional BOE. 

oren

  • Moderator
  • First-year ice
  • Posts: 6192
    • View Profile
  • Liked: 2252
  • Likes Given: 1890
Re: MOSAiC news
« Reply #999 on: August 19, 2020, 11:47:24 PM »
Thanks for the great analysis A-Team, including the parts about TPD vs. normal CPD, and the fractional BOE evidenced by these photos.