By which route will itp128 leave the Arctic Ocean?

[uniquorn]

..

[Neven]

I'm going for Fram. 

[Jim Hunt]

I'm going for Fram. 

Seconded.

[HapHazard]

Well I'll go against the grain of the total rookie n00bs above me there ^ and go with Nares.

[oren]

Earlier in the plot I would have said Fram, now it seems as if Nares is the probable choice, and further west is possible.

[Jim Hunt]

Now it seems as if Nares is the probable choice, and further west is possible.

Hence the poll!

[gerontocrat]

Do these buoys, like boats, ever wash up on the beach (caught on a lee shore with strong onshore winds)?

If the answer is yes, that's my choice.

[Jim Hunt]

Do these buoys, like boats, ever wash up on the beach

They do:

https://www.whoi.edu/oceanus/feature/a-buoys-long-strange-trip/

[A-Team]

They do: https://www.whoi.edu/oceanus/feature/a-buoys-long-strange-trip/

The strange part is that WHOI thinks Ellesmere has a continental slope 160 km north whereas the near absence of a shelf along the entire CAA/AK coast, regardless of the state of glaciation, and indeed the lopsidedness of the Arctic Ocean in this regard, is one of its most remarkable and best known features.

itp128 could be out there a very long time especially if it drifts a bit more to the west.

[SteveMDFP]

Well I'll go against the grain of the total rookie n00bs above me there ^ and go with Nares.

Well, yeah, that would be the most direct exit.  But the Fram exit handles an order of magnitude (or more) volume.  I'd personally favor the more high-volume exit, but it could certainly go either way.

[seaice.de]

https://det.social/@seaice/109927235749113455

[A-Team]

Hycom shows the buoy drifting east for the next week but not all that far. I am voting for moving west, stalling out halfway to Banks Island by May.

[gerontocrat]

No help from GFS wind forecasts....

Looking at the area of interest,
Now - a stiff SE breeze - towards the  CAA,
Monday - a Westerly gale towards the Fram,
Wednesday - almost dead clam,

& after that, a succession of lows from the South with calm periods inbetween

a gif attached . click to run & enlarge

[A-Team]

Wind won't be moving this buoy too much in the week to come ...

Last buoy status on 2023/2/26 61637 UTC:
temperature = -24.9 °C
position 85.2899° N, 73.8542° W

https://www2.whoi.edu/site/itp/data/active-systems/itp128/

[uniquorn]

Agreed, with the wind blowing SW up the Nares Strait and cold temps there is a possibility of a late arch forming. Nevertheless itp128 drifted almost 3km almost due south yesterday, roughly 40° right of wind.

distHaversine(c(73.9984,85.3138),c(73.8542,85.2899),r=6378137 )
[1] 2967.675

Maybe questionable where the shelf break is but there is a good drop around 95km north of Ellesmere.
Further to the animation by seaice.de here is a closer look at itp128 drift since feb1. Occasionally static. Unlikely imo to get grounded on the coast while still in a probable 2m thick floe. Click for motion. itp110 grounded after its floe melted out in Mackenzie bay and has never been collected for a couple of years. It's still reporting location as of yesterday.

rammb with rough location of itp128 as black dot.

[A-Team]

3km almost due south yesterday, roughly 40° right of wind

Recalling (?) a windy day during the Polarstern year gave 20 km displacement. This iGIS tool is giving less of an angle of ice movement relative to the wind (also was quite variable during that year) and will not align with the wind at the buoy's current location due to variables such as coriolis, immovable nearby land and low back-pressure at Nares funnel. Hycom did quite well on its first day of prediction per #11 though motion there is hard to measure quantitatively.

I'm not of the opinion that the buoy is currently over the CAA continental shelf as defined geologically or by international agreement (though Canada filed a land grab in 2019 that included the North Pole, contested by Denmark and Russia who both say Lomonosov Ridge is theirs because it rifted):

A continental shelf typically extends from the coast to depths of 100–200 metres (330–660 feet). It is gently inclined seaward at an average slope of about 0.1°. In nearly all instances, it ends at its seaward edge with an abrupt drop called the shelf break. Below this lies the continental slope, a much steeper zone that usually merges with a section of the ocean floor called the continental rise at a depth of roughly 4,000 to 5,000 metres (13,000 to 16,500 feet). A few continental margins—such as those off the Mediterranean coast of France and at Porcupine Bank, off the western coast of Ireland—do not have a sharply defined break in slope but rather maintain a generally convex shape to the seafloor.

The average width of continental shelves is about 65 km (40 miles). Almost everywhere the shelves represent simply a continuation of the continental landmass beneath the ocean margins. Accordingly, they are narrow, rough, and steep off mountainous coasts but broad and comparatively level offshore from plains. The shelf along the mountainous western coast of the United States, for example, is narrow, measuring only about 32 km (20 miles) wide, whereas that fringing the eastern coast extends more than 120 km (75 miles) in width. Exceptionally broad shelves occur off northern Australia and Argentina. The world’s largest continental shelf extends 1,500 km (about 930 miles) from the coast of Siberia into the Arctic Ocean.

The definition of the continental shelf and criteria for the establishment of its outer limits

    The definition of the continental shelf and the criteria by which a coastal State may establish the outer limits of its continental shelf are set out in article 76 of the Convention. In addition, the Third United Nations Conference on the Law of the Sea (the "Conference") adopted on 29 August 1980 a "Statement of Understanding" which is contained in Annex II to the Final Act of the Conference.

    The term "continental shelf" is used by geologists generally to mean that part of the continental margin which is between the shoreline and the shelf break or, where there is no noticeable slope, between the shoreline and the point where the depth of the superjacent water is approximately between 100 and 200 metres. However, this term is used in article 76 as a juridical term. According to the Convention, the continental shelf of a coastal State comprises the submerged prolongation of the land territory of the coastal State - the seabed and subsoil of the submarine areas that extend beyond its territorial sea to the outer edge of the continental margin, or to a distance of 200 nautical miles where the outer edge of the continental margin does not extend up to that distance. The continental margin consists of the seabed and subsoil of the shelf, the slope and the rise. It does not include the deep ocean floor with its oceanic ridges or the subsoil thereof .

    According to article 76, the coastal State may establish the outer limits of its juridical continental shelf wherever the continental margin extends beyond 200 nautical miles by establishing the foot of the continental slope, by meeting the requirements  of article 76, paragraphs 4 - 7, of the Convention (see also figure).

https://www.britannica.com/science/continental-shelf
https://www.un.org/depts/los/clcs_new/continental_shelf_description.htm
https://thebarentsobserver.com/en/arctic/2019/05/canada-files-submission-establish-continental-shelf-outer-limits-arctic-ocean
https://www.igismap.com/map-tool/bearing-angle

[uniquorn]

Yep, should have calculated it instead of using eyeballs.

bearing(c(-73.9984,85.3138),c(-73.8542,85.2899),a=6378137, f=1/298.257223563)
[1] 153.6295

That's -26.3705 according to R.

oops

bearing(c(-73.8542,85.2899 ),c(-73.9984,85.3138),a=6378137, f=1/298.257223563)
[1] -26.22683

interesting

[uniquorn]

The code above makes it trivial to add bearing to itp128 data. Here is a first attempt to look at it with drift speed. feb21-27. This morning headingbearing 10° south of due east at nearly 1km/h. (I think)

drift animation, feb1-27

edit: A closer look suggests the ice is never totally static. Could be gps inaccuracy.
feb20-27

[kassy]

A closer look suggests the ice is never totally static. Could be gps inaccuracy.
feb20-27

So the big swings at 0 speed are mostly artefacts?

[uniquorn]

artefacts or not

Could be another poll on that. I can imagine the ice moving small distances forward and backwards as it ridges or as leads form. Would appreciate other opinions.

An even closer look at feb23-25 when drift speed was very low.

[johnm33]

artefacts or not

My guess is small movements at 180 to one another. Imo that part of the ice has a number of forces acting on it, one is waves passing beneath, if a large slow wave a couple of meters high passed through, the ice could 'surf' down the building wave then as the peak passed 'surf' right back again, there are some signs of waves passing through [probably in a deeper layer], but I'm not at all sure about 'headings'.

[A-Team]

More on methods available?

Two GPS positions are being compared. I am guessing they differ by 24 hours. When the buoy is not moving much, in effect that's differing two very small numbers. That may be pushing the calculation too close to the error zone of the GPS (which historically has been rocky at high latitudes).

Note too this is not a line integral providing total distance travelled but rather just end points chord. So if an off-center buoy is going around in circles as its floe rotates or is rocking back and forth perhaps covering a lot of ground but at the end of the day it appears not to have moved much.

If one degree of latitude is 111 km, then the buoy's nominal 0.0001 degree precision is 11.1 m, realistically 55.5m if not 100m. The calculation too has its approximations such as assuming a spherical earth and great circle motion.

An alternative to a formal error calculation, since cpu cycles cost nothing, is repeating the bearing calc using 1x, 2x, 3x, 4x days etc to get a measure of the graph-steadying effect.

[uniquorn]

When overlaying the curious Nares fracture extensions onto bathymetry they line up very conveniently with the trough, perhaps suggesting a correlation with some returning Atlantic water taking the easier route to the Nares rather than the sharp deviation eastwards to the Fram.

itp128 records its position every 30m. Here we look at the distance travelled (in metres) during that time from feb25-28. csv attached to encourage further analysis and critique of method.

[A-Team]

curious Nares fracture extensions onto bathymetry

Have we ever seen these parallel bounding fracture extensions before? Not that I can recall. Amirite about return Atlantic Water suggestion?

In the cvs, what does distb mean? Brg is likely bearing, with some potential confusion as the angle changes from positive to negative around 0 and 180. I could not locate online animation software that would draw angle/speed vectors. They went way too far too in imputed precision, would be lucky to have one decimal point. Bearing swings around wildly at 30'; needs a recalc at longer intervals.

-4.74090714259496
89.9998505166933
170.582032200922
-146.435673274153
-153.543435283354
-140.32722597657
-140.326635485674
-143.258567430665
-140.325454545265
-143.257415385105
-149.858481124362
-143.256263370537
-89.9996013784278
-130.730466221526
-153.538582959901
-126.993563466743
-123.8083195367
-89.9994518957363

[uniquorn]

Have we ever seen these parallel bounding fracture extensions before?

There was a hint of them last February.
https://go.nasa.gov/3J2CqzA



At that time they looked more like an extension of the Fram funnel, which they may well be.

    distb <- distHaversine(c(data$Lon,data$Lat),c(data$Lon[i-1],data$Lat[i-1]),r=6378137)

some square brackets disappeared
Distance drifted since the previous latlon, no correction for missing entries so may not always be 30minutes.

    brg <- bearing(c(data$Lon[i-1],data$Lat[i-1]),c(data$Lon,data$Lat),a=6378137, f=1/298.257223563)

Could be i-6, every 3hours?

amirite?
I think returning Atlantic water may be forced along the trough and meet the CAA coastal current.

------------------

itp128 drift since feb24 when the poll began.  https://go.nasa.gov/3Z6TtWt

[uniquorn]

itp128 drift update, distance travelled every 30m in metres, bearing is 3hr difference.
Drift was slow yesterday.

[uniquorn]

Agreed, with the wind blowing SW up the Nares Strait and cold temps there is a possibility of a late arch forming.

Two large floes helping an arch to form today. -24to-29C and 45km southwesterlies forecast for the next 2 days. A good opportunity for a northern arch to firm up.
https://col.st/mEO2k

[johnm33]

'My guess' The recent extreme change of mslp north of Bering would suggest several enhanced pulses of incoming from the Pacific. Where these meet the rise of the plateau which the bouy moves across, there would be a build up of pressure and several series of waves created over a number of tides, they would pass more or less orthogonally past the bouy, hence the to and fro, then once a flow was established remove the inertia neccesary to force wave creation.

[A-Team]

returning Atlantic water may meet the CAA coastal current. Have we ever seen these parallel bounding fracture extensions before?

I could not find a dedicated published explanation for the uppermost Nares arch which we often see progressing in Lincoln Sea but never beyond a certain extent. It is driven primarily by differences in elevation between the AO and Baffin Bay (ie air column).

These bounding fault lines could be an early indication of arcs developing much farther north but what new forces (or ice weaknesses) would be responsible?

It is fairly difficult to study this area experimentally because of the shifting ice though buoys do pass through and stop-and-go airplane landings have sampled the situation.

These don't measure the currents at depths though; an acoustic doppler current profiler off a bottom mooring is usually needed for that. There is practically no continental shelf in this area (100-150m).

It is not safe to assume that the CAA and the return Atlantic Water currents are at the same depths or could mix if densities (ie salinities) are different. There is a broken-off piece of continental shelf (labelled R) that might deflect returning AW. The Lomonosov shelf ridge itself subsided long ago and now only reaches up to -985 m.

[johnm33]

Where you have the L is above -500m, and https://icyseas.org/ has I believe a device beneath Peterman which measures the Atlantic waters, which pass through, in some way.

[uniquorn]

Unfortunately itp128 profiler battery ran out in jan2022 so no ocean data will be available but a warming signal has been detected at 200-450m in the Nares. How does warmer water get there?

https://tc.copernicus.org/articles/16/3021/2022/tc-16-3021-2022.pdf
Ongoing grounding line retreat and fracturing initiated at the Petermann Glacier ice shelf, Greenland, after 2016
Romain Millan, Jeremie Mouginot, Anna Derkacheva, Eric Rignot, Pietro Milillo, Enrico Ciraci,
Luigi Dini, and Anders Bjørk

A warming signal was detected at depth from the 1970s to the 2000s, with a warming of roughly 0.1 ◦C. An even stronger signal has taken place in the last decade (Fig. 5), with a temperature that increased from 0.1 ◦C in 2000 to 0.3 ◦C in 2020.

----------------------------------

The arch was too pointy and didn't hold.

[seaice.de]

https://seaice.de/nh_AMSR2_itp128_zoom_latest.gif

[Jim Hunt]

Definitely heading for the Fram Strait Lars!

[be cause]

 ... certainly what the forecasts would suggest , along with a lot of nice ice .

https://drive.google.com/uc?export=view&id=15PIjBj0lUD0FpF775sa3HvfJ5CPkGNVz





  error fixed ?

[A-Team]

HTTP ERROR 403 untested non-working link
headed nowhere at the moment
warm water comes from down south

The first image below shows the hycom forecast to 08 Mar 2023; the second the latter days of Lars' latest AMSR2 inverted; the third a very hypothetical infill of the bounding leads; the fourth the averaged envelope of the extending leads.

[uniquorn]

headed nowhere at the moment

Slow drift within the same 2km path over the last 56h.

rammb, lincoln sea, latest 5hours https://col.st/FXo8G
Ice in the funnel is weak with many small fractures.

[A-Team]

Ice in the upper funnel is weak with many small fractures.

Somehow these bounding fractures are the ice pack expression of a weak surface current (taking the Nares funnel as a weak upriver Niagara Falls). Loss of buttressing then creates a falling domino effect on the edge of the ice.

Depth structure of velocity could be determined with drifting floats hopefully surfacing in Baffin Bay but don't recall them used much except for the west spitzbergen current.

Sub-surface floats: These are autonomous free-drifting platforms gathering data at mid-depth and surfacing from time to time to transmit. These platforms are coordinated under the Argo Program ....

https://www.ocean-ops.org/dbcp/platforms/types.html
https://www.sciencedirect.com/science/article/pii/S096706370700132X

[uniquorn]

https://seaice.de/nh_AMSR2_itp128_zoom_latest.gif

Very nice animation though when looking at it frame by frame it has a missing frame on feb28 and also appears to show highest drift on feb28-mar1 but my calcs show higher drift on feb27. I hope I am not doing something wrong.

[seaice.de]

https://seaice.de/nh_AMSR2_itp128_zoom_latest.gif

Very nice animation though when looking at it frame by frame it has a missing frame on feb28 and also appears to show highest drift on feb28-mar1 but my calcs show higher drift on feb27. I hope I am not doing something wrong.

Thank you!
I just discovered that the frame for 2023022812_030100 was stored already in the March folder and is therefore missing in my animation.

[uniquorn]

ok, here's hoping this ani is correct. 3days left for me to vote. Drift was roughly 8km eastnoreast? yesterday.

[Phil.]

ok, here's hoping this ani is correct. 3days left for me to vote. Drift was roughly 8km eastnoreast? yesterday.

I'm a bit confused by the directions on your map, it seems more like ESE to me?

[uniquorn]

The arrow, top right, is pointing north, the label obscured by bathy colour. It's tricky at that resolution, with this method, to get many lat labels in.

[crandles]

I am also confused.



seems to have it going S of East

[gerontocrat]

To me it looks like the Nares funnel beckons.

[oren]

Yeah, I'm sticking with Nares.

[uniquorn]

I'm drifting towards Fram but still undecided. See what the next two days brings. Nares is very much open so there's little resistance should a northerly wind arrive.

itp128 has drifted 0.07° N since mar1.

2023   60.26178   -71.6484  85.2397
2023   61.26182   -71.5094  85.2506
2023   62.26189   -70.3494  85.2986
2023   63.26166   -69.2031  85.3104

woldview, drift since feb24  https://go.nasa.gov/3ygOLtq
north of FJL very flaky again

ascat, lincoln sea, jan1-mar3

[uniquorn]

whoi itp128 had very slow drift yesterday, southerly drift was 0.0011°

Year      Day              Lon        Lat
2023   63.26166   -69.2031  85.3104
2023   64.26171   -69.1830  85.3093

Taking some static crops from seaice.de animation on feb22 we see itp128 within the possible extended Nares funnel. On feb25 there is a brief fracture, probably along a compressive weakness, that releases pressure on the funnel area.
On mar3 the more familiar fracture is just visible across the north of Lincoln Sea that, in the past, used to show the extent of the 'last ice area'. With the Nares open, that appears to sweep further north in an arc, rather than straight across the from the northernmost land points.
The 4th frame shows the main fram funnel fracture to the north and the old 'last ice area' limit in green.

Focussing on the rammb animation, drift speed is clearly faster northeast of the main fram funnel line. itp128 likely sits in the middle of the slow lane to Fram. The large floe was not so strong and split across the middle.

worldview drift since feb24  https://go.nasa.gov/3JfA1Sb

Things could change tomorrow on the last day to vote.

[uniquorn]

ITP125 was deployed on a 0.8 m thick ice floe in the Transpolar Drift on October 1, 2021 at 78° 45.0 N, 179° 39.4 W in collaboration with the Nansen and Amundsen Basins Observational System (NABOS) project from the Russian Research Vessel Treshnikov. On the same icefloe, a US Army Cold Regions Research and Engineering Laboratory (CRREL) Seasonal Ice Mass Balance Buoy 3 was also installed. The ITP includes a dissolved oxygen sensor and is operating on a fast sampling schedule of 4 one-way profiles between 5 and 760 m depth each day.

ITP128 was deployed on a 1.36 m thick ice floe in the Transpolar Drift on September 30, 2021 at 77° 26.5 N, 179° 54.3 E in collaboration with the Nansen and Amundsen Basins Observational System (NABOS) project from the Russian Research Vessel Treshnikov. On the same icefloe, a US Army Cold Regions Research and Engineering Laboratory (CRREL) Seasonal Ice Mass Balance Buoy 3 was also installed. The ITP is operating on a fast sampling schedule of 4 one-way profiles between 5 and 760 m depth each day.

itp125 looks more likely to exit via Nares imo. I'm going to vote for Fram for itp128.

[seaice.de]

I once enjoyed drifting towards Fram Strait, therefore I voted for it.

[nadir]

The moment of truth comes in the next few days I think. It will end up in Fram. Unless Coriolis decides otherwise.