Support the Arctic Sea Ice Forum and Blog

Author Topic: 'implausibly stationary ice' as a method of shoal discovery  (Read 2697 times)

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
'implausibly stationary ice' as a method of shoal discovery
« on: August 24, 2019, 08:08:36 PM »
Reposting here for easier reference.
Following up on persistent ESS ice in post https://forum.arctic-sea-ice.net/index.php/topic,2591.msg224137.html#msg224137. Here showing a 16days/sec worldview animation from feb2015-aug2019 of the two probable shoals which look like they are well inside the GMRT bathymetry 25m contour, perhaps indicating a near surface gravel bank or similar. Elevation indicates -20m. https://www.gmrt.org/GMRTMapTool/np/

Polarview sentinel1 image of the two possible shoals from 20190823
72.3031 164.2392 EPSG:3413
72.7482 161.3865 EPSG:3413
https://www.polarview.aq/arctic

GMRT bathymetry, heavy contrast to show contours with worldview terra modis aug23 overlay(rotated 45deg)
« Last Edit: August 24, 2019, 08:25:05 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #1 on: August 24, 2019, 08:57:56 PM »
Looking for nearest survey on https://maps.ngdc.noaa.gov/viewers/bathymetry/.

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #2 on: August 25, 2019, 01:09:30 PM »
16days/sec worldview aqua modis animation from feb2012-oct2014 of the two probable shoals
« Last Edit: August 25, 2019, 01:38:40 PM by uniquorn »

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #3 on: August 25, 2019, 01:34:20 PM »
This is one amazing find Uniquorn. I propose the name Uniquorn-floes for them.
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #4 on: August 25, 2019, 02:03:28 PM »
This is one amazing find Uniquorn. I propose the name Uniquorn-floes for them.
+1
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #5 on: August 25, 2019, 02:18:18 PM »
Maybe something a touch more siberian?

16days/sec worldview aqua modis animation from feb2009-oct2011 of the two probable shoals

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #6 on: August 25, 2019, 02:28:27 PM »
Posting for a friend:
https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)

http://snagfilms-a.akamaihd.net/39/5e/604ba7f44a73b079418532e4686b/submarine-aground-n-4085067.jpg

Quote
On 8 January 2005, the USS San Francisco collided with an undersea mountain about 675 km southeast of Guam while operating at maximum speed (30-33 knots, over 56 km/hr) at a depth of 160 m. The seamount's location is  7°45'06"N  147°12'36"E between Pikelot and Lamotrek Atolls.

The collision was so serious that the vessel was almost lost; accounts detail a desperate struggle for positive buoyancy to surface after the forward ballast tanks were ruptured. Ninety-eight crewmen were injured of the 137 on board; one died from head injuries on 9 January. Other injuries included broken bones, spinal injury & lacerations.

San Francisco's forward ballast tanks and her sonar dome were severely damaged, but her inner hull was not breached and there was no damage to her nuclear reactor. She surfaced and arrived in Guam on 10 January accompanied by USCGC Galveston Island, USNS GYSGT Fred W. Stockham, and USNS Kiska, as well as MH-60S Knighthawks and P-3 Orion maritime patrol aircraft.

The seamount that San Francisco struck did not appear on the chart in use at the time of the accident, but other charts available for use indicated an area of "discolored water", an indication of the probable presence of a seamount.

The Navy determined that information regarding the seamount should have been transferred to the charts in use—particularly given the relatively uncharted nature of the ocean area that was being transited—and that the failure to do so represented a breach of proper procedures.

San Francisco had recently replaced her nuclear fuel and she was thus expected to remain in service until 2017, so the Navy determined that repair of the submarine was in its best interests. Temporary repairs were made in Guam to provide watertight integrity and forward buoyancy so that the boat could safely transit to the Puget Sound Naval Shipyard for more extensive repairs.

In June 2006, it was announced that San Francisco's bow section would be replaced at the Puget Sound Naval Shipyard with the bow of USS Honolulu. The cost of her bow replacement was estimated at $79 million, compared with $170 million to refuel and overhaul the nuclear reactor of Honolulu.

On 10 October 2008, San Francisco undocked after a successful bow replacement at the Puget Sound Naval Shipyard. The dry-docking project involved cutting more than one million pounds of forward ballast tanks and sonar sphere off the former USS Honolulu and attaching them to San Francisco.

San Francisco completed repairs and sea trials in April 2009, then shifted homeport to Naval Base Point Loma, San Diego, California.an Francisco returned to Point Loma from her sixth deployment in October 2016.  She is slated to become a moored training ship at the Navy's Nuclear Power Training Unit in Charleston, South Carolina.
« Last Edit: August 25, 2019, 02:34:42 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #7 on: August 25, 2019, 03:07:46 PM »
16days/sec worldview aqua modis animation from feb2006-oct2008 of the two probable shoals

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #8 on: August 25, 2019, 03:42:44 PM »
16days/sec worldview aqua modis animation from feb2003-oct2005 of the two probable shoals

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #9 on: August 25, 2019, 04:05:10 PM »
16days/sec worldview aqua modis animation from feb2000-oct2002 of the two probable shoals

Some lovely big floes in this one. And quite a few missing days.

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #10 on: August 25, 2019, 04:07:41 PM »
So the two Uniquorns have been well and truly established ... or should that be the Duoquorns?
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #11 on: August 25, 2019, 06:24:25 PM »
Biquorns?
Here attempting to show one cloudless image per year from near the end of the season to detect shoal movement, 2000-2014 (might have to check these)

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #12 on: August 26, 2019, 02:21:00 PM »
Unihamburg amsr2-uhh and ascat, oct2018-jul2019 suggesting there may be a third shoal further south.
edit: Added worldview aqua modis, feb2017-aug2019 72N162E.

72.30 164.23 EPSG:3413
72.74 161.38 EPSG:3413
71.60 163.52 EPSG:3413

70.70 165.76 EPSG:3413  possible fourth

« Last Edit: August 26, 2019, 03:44:01 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #13 on: August 26, 2019, 04:25:19 PM »
70.70 165.76 EPSG:3413

DrTskoul

  • Nilas ice
  • Posts: 1451
    • View Profile
  • Liked: 208
  • Likes Given: 60
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #14 on: August 26, 2019, 05:59:02 PM »
Awesome

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #15 on: August 26, 2019, 07:24:12 PM »
It would appear that ESS is fairly shallow in a few places.
72.30 164.23 EPSG:3413
72.74 161.38
71.60 163.52
70.70 165.76
adding
74.36 157.90
worldview aqua modis, feb2017-aug2019

Also worldview ess, aug18 2019 showing the rough locations (poorly circled)

vox_mundi

  • Nilas ice
  • Posts: 1306
    • View Profile
  • Liked: 426
  • Likes Given: 92
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #16 on: August 26, 2019, 08:46:50 PM »
Fantastic efforts uniquorn!

You may have naming rights

This year's Symposium, will be held in Portsmouth, New Hampshire, USA, 6th November 2019.

Join the world’s experts on ocean floor mapping for a special one-day event focused exclusively on bathymetry

https://www.gebco.net/news_and_media/symposium_2019_update.html

To ensure that features’ names don’t get renamed on subsequent cruises, scientists turn to a reliable tool: the General Bathymetric Chart of the Oceans (GEBCO) Gazetteer online interactive map.

https://www.ngdc.noaa.gov/gazetteer/
(Just select shoal or shoals and it will identify all known features)

https://www.gebco.net/data_and_products/gridded_bathymetry_data/
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #17 on: August 27, 2019, 01:05:40 PM »
It would appear that ESS is fairly shallow in another place.
72.30 164.23 EPSG:3413
72.74 161.38
71.60 163.52
70.70 165.76
74.36 157.90
adding again
74.72 154.04  worldview aqua modis, feb2017-aug2019

Will update the overview image in a while.

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #18 on: August 27, 2019, 02:16:42 PM »
map from T. M. Cronin et al.: Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins       https://www.clim-past.net/13/1097/2017/cp-13-1097-2017.pdf

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #19 on: August 27, 2019, 02:46:50 PM »
Am I mistaken or are some of the shoals shown on the map?
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #20 on: August 27, 2019, 03:00:51 PM »
Suggestion from a friend
pingo, also called a hydrolaccolith or a bulgunniakh     https://en.wikipedia.org/wiki/Pingo
Quote
Hydraulic (open-system) pingos result from groundwater flowing from an outside source, i.e. subpermafrost or intrapermafrost aquifers. Hydrostatic pressure initializes the formation of the ice core as water is pushed up and subsequently freezes. Open-system pingos have no limitations to the amount of water available unless the aquifers freeze. They often occur at the base of slopes and are commonly known as Greenland type. The groundwater is put under artesian pressure and forces the ground up as it makes an expanding ice core. It is not the artesian pressure itself that forces the ground up, but rather the ice core that is being fed the water from the aquifer. These are often formed in a thin, discontinuous permafrost. These conditions allow an ice core to form, but also provide it with a supply of artesian ground water. If water pressure entering an artesian pingo is strong enough, it can lift the pingo up allowing a sub-pingo water lens to form underneath. However, if the water lens starts to leak water it can cause subsidence which can compromise the structure.[8] These pingos are often oval or oblong shaped.
« Last Edit: August 27, 2019, 03:18:08 PM by uniquorn »

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #21 on: August 27, 2019, 03:07:26 PM »
For a moment there I thought it was your friend that had those unfortunate nicknames ...

So a sea-floor pingo - how about a gas-hydrate pingo?

https://www.revolvy.com/page/Gas-hydrate-pingo
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #22 on: August 27, 2019, 03:13:30 PM »
Am I mistaken or are some of the shoals shown on the map?
one is, I think, in the 0-10m range. The rest are 10m-20m,  but these shoals must be much shallower to ground, say, 0.5m ice on Aug18. Perhaps the ice is much much thicker (I wish)
Quote
how about a gas-hydrate pingo?
Maybe. The current theory is

' pingoes/ice wedges/LGM ice features (rather than rock outcrops or volcanic peaks) -- fresh water ice/dirt bulges. The sea water is near -1.8ºC too cold to melt them. That is why they are flush with sea level and occur each year. So each year sea ice moves over them and gets stuck. Later the sea ice still in the water melts out or is blown away or moved away by tidal currents leaving the grounded ice to melt later from air exposure as it has lateral but no bottom melting.'
« Last Edit: August 27, 2019, 08:07:14 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #23 on: August 27, 2019, 04:17:03 PM »
A rough overlay of the bathymetry map from T. M. Cronin et al. and worldview ess, aug18 2019 showing the rough locations (poorly circled)   click to run
tech note: lost some of the worldview colours converting to gif
« Last Edit: August 27, 2019, 04:27:03 PM by uniquorn »

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #24 on: August 27, 2019, 04:27:03 PM »
1, 2 and 4 match shallow waters, but 3 and 5 don't.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #25 on: August 27, 2019, 04:30:42 PM »
assuming correlation of the rough overlay. From left to right
2 is shallow at 0-10m
1 and 4 at 10-20m
3 and 5 at 20-30m
5 at 30-40m

thanks for checking :)
6 is not on the map but looks like 0-10m (close to New Siberian islands)
« Last Edit: August 27, 2019, 04:39:20 PM by uniquorn »

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #26 on: August 27, 2019, 08:03:26 PM »
So, the bathymetry map is incorrect...

What could it be? I'm thinking sandbanks maybe? Could it be big rocks underwater? Or maybe gas hydrates growing up? Or causing a cold mini ocean climate in these areas so that ice can get thicker here?
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #27 on: August 27, 2019, 10:46:44 PM »
Working names for now are ESS S-1 to ESS S-5 with S for shoal. 'Left to right' in Greenland down orientation which is east to west for Siberians
ESS-1S 70.7 165.8
ESS-2S 71.6 163.5
ESS-3S 72.3 164.2
ESS-4S 72.7 161.4
ESS-5S 74.4 157.9

Animations of:
ESS-1S, worldview, aqua modis, feb2017-aug2019, non cloudy days, in gif format, lossy compression to reduce file size.
ESS-2S, ESS3S and ESS4S, worldview, aqua modis, feb2017-aug2019, every other day with lossy compression.
ESS-5S, worldview, aqua modis, feb2017-aug2019, non cloudy days, lossy compression.
A rough overlay of the bathymetry map from T. M. Cronin et al. and worldview ess, aug18 2019 showing the rough locations (poorly circled)


Tech note: using gif here to cover all OS and browser types. File sizes have been reduced as far as possible.
« Last Edit: August 27, 2019, 11:12:47 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #28 on: August 28, 2019, 12:49:36 PM »
Some background research on Laptev shoals from A-Team
Quote
Here is more on incredible parallel to ESS shoals but on the Laptev side of the NSI. A bit of land remains today (Yaya island, now 0.5 m above sea level). Weird to see ice/rock feature not far from islands with conventional hard rock islands. The other mystery is the length ... requires a chain of pingos. Note the 5 ESS shoals are kinda in a line which would fit with a fault line and methane pingos along it,

https://commons.wikimedia.org/wiki/File:Former_Vasilyevsky_Island,_New_Siberian_Islands,_Russia,_Sentinel-2_satellite_imagery,_2-SEP-_2016.png?

google translation from  the russian wiki:
https://ru.wikipedia.org/wiki/Васильевский_остров_(Новосибирские_острова)

"Vasilyevsky is a former island (currently Vasilyevsky Shoal, Vasilyevsky Bank) in the southwestern part of the Novosibirsk Islands (the extreme west of the Lyakhovsky Islands), in the eastern part of the Laptev Sea. Before it disappeared, it was one of the smallest islands in the archipelago. Shoal (or bank) was named after the island. To the northeast is the Semenovskaya Bank, to the east is Stolbovoy Island. In 2013, a new island (Yaya) was discovered in the area.

Since its discovery, Vasilievsky Island has rapidly declined in size, until it completely disappeared by the mid-1930s due to the melting of ice mixed with rocks. The shallowest depth in 1965 was 0.8 m. Then, the increase in shoal depths continued due to melting of icy inclusions in the rocks of the bottom, chemical processes and under the influence of sea waves."

Tass:

73.59'086 "N and 133.07'398" E. “It looks like a ridge of hummocks,” said Gukov. The results of the flight convinced the director of the reserve that "ice played a decisive role in the formation of the island, raking, like a bulldozer, in shallow sediment." “This is evidenced by the location of the hummocks,” Gukov said.

It was first noticed and mapped in 1814 by Yakut trappers who mined mammoth tusks in these places. According to the materials of the Hydrographic Expedition of the Arctic Ocean, in 1912 the length of Vasilievsky Island was  4.6 km in length, it had coasts 15-16 meters high. However, according to Gukov, even such a height of the coast did not save the island, and it was eventually washed out by the waves.

The new island is much smaller - about 150 by 150 m, and it rises above sea level by only half a meter. Vasilievsky Island belonged to the Lyakhovsky Islands archipelago, which, together with the Anjou and De Longa archipelago, are included in the large island association of the Novosibirsk Islands.

When first discovered, Vasilievsky Island was 7.4 km long and 0.5 km wide.

Semenovsky Island once joined it:

September 10, 1881 American expedition D.V. made a two-day stop De Longa, sailing after the death of her expeditionary ship "Jeannette" in the ice of the Laptev Sea to the mouth of the Lena River in three boats. In the diary of D.V. De Long recorded the island’s width of 1/8 mile and a height of 3 to 9 m and noted that the island was apparently being eroded. On the top of the hill dominating the island, he found the remains of deer horns and mammoth teeth.

August 19, 1912 icebreaker-transport  “Vaigach” anchored at a depth of 8.2 m at a distance of two miles from about. Vasilievsky.   Neupokoev noted that the islands of Semenovsky and Vasilievsky did not exceed 2.5 miles in length. He suggested that once instead of two islands there was one large island, which is confirmed by the presence of an extensive shallow extending to the east, northeast and southeast from the islands of Semenovsky and Vasilyevsky.

the Semenovsky and Vasilievsky islands consist of subsoil ice covered with a layer of silt and various kinds of tundra formations, two feet thick. The ice at the coastline is exposed and is rapidly being destroyed due to melting.

http://www.evgengusev.narod.ru/laptev/kluev-1981.html

example of coastal ice/dirt decay
Worldview, ESS-1S, clear day, 2000-2018

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #29 on: August 29, 2019, 02:08:56 PM »
better looking image of ess-1s to ess-5s with 10m, 25m contours and scale courtesy of A-Team
« Last Edit: August 29, 2019, 03:33:02 PM by uniquorn »

gandul

  • New ice
  • Posts: 40
  • de verdad
    • View Profile
  • Liked: 16
  • Likes Given: 0
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #30 on: August 29, 2019, 02:24:09 PM »
It occurs to me that the ships covering the Northern Route must have these shoals on cartography. Otherwise they can have a serious accident if they breaking the ice and go on top of one of these.
Any web provides cartography for free? (doubt it)
No me lo trago

oren

  • Young ice
  • Posts: 4302
    • View Profile
  • Liked: 763
  • Likes Given: 1230
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #31 on: August 29, 2019, 07:43:34 PM »
I salute you uniquorn for the amazing detective work. This deserves a paper or something IMHO.

binntho

  • Grease ice
  • Posts: 974
    • View Profile
  • Liked: 240
  • Likes Given: 71
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #32 on: August 29, 2019, 08:16:22 PM »
I salute you uniquorn for the amazing detective work. This deserves a paper or something IMHO.
+1
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #33 on: August 30, 2019, 02:19:38 PM »
The method works quite well but, as suggested upthread, likely that shipping authorities are already aware of such hazards. A-Team found the map below from THE NORTHEN SEA ROUTE ADMINISTRATION.
http://www.nsra.ru/en/navigatsionnaya_i_gidrometinformatsiya/chart_ice_es_sea.html

Here showing a rough overlay of the worldview image of the shoals upthread (resized and rotated) and the map from the arctic & antarctic research institute. Quite a good correlation with the 5 detected though it looks like I missed some. Interesting that one isn't shown just west of the new siberian islands.
click to run.

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #34 on: September 01, 2019, 02:40:48 PM »
Here looking at an area south of the New Siberian Islands marked on the worldview image from aug1. There would appear to be 6 possible shoals in the area since 2001.
worldview, clear days with possible shoals, 2001-2019
73N 151.5
edit: rather random date order towards the end of that ani but no one has said anything ;)
updating here with visible coordinates of what may be 2 quite long shoals edit2: or a string of pingoes. The larger one to the east may stretch south (above) the animation.
ESS-?S, 73.15, 152.23,
ESS-?S, 73.07, 152.22,
ESS-?S, 73.17, 152.12,
ESS-?S, 73.217, 152.07,
ESS-?S, 72.924, 152.12,
ESS-?S, 72.94, 151.88,
ESS-?S, 72.76, 152.35,

the smaller one to the west (rhs on image)
ESS-?S, 73.04, 151.37,
ESS-?S, 73.17, 151.31,

added worldview animation of southern tip in 2015
« Last Edit: September 02, 2019, 06:27:48 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #35 on: September 01, 2019, 05:04:54 PM »
example of false positive at 74.5N 167.5
unihamburg amsr2-uhh, ess, aug21
worldview, terra modis, relevant summer months, 2017-2019

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #36 on: September 01, 2019, 07:48:37 PM »
shoal pinball, 75N 155, 20010704-24, worldview

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #37 on: September 02, 2019, 12:16:21 PM »
Checking 72N 170 based on polynya seen in amsr2uhh and ascat on day140-142 and earlier low concentration in the same area. It appears to be another false positive possibly due to wind based gyre type movement.
worldview animation of ESS, ~72N 170, 2018-2019, summer months, lossy compression
edit:slower animations
« Last Edit: September 03, 2019, 12:58:55 PM by uniquorn »

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #38 on: September 02, 2019, 06:34:57 PM »
Apologies for the high speed animation above. Due to the ezgif compression I can't easily slow it down without repeating the whole process again.

Some more interesting background from A-Team
Quote
Vessel hit sandy shoal at low speed in Northwest Passage
CBC News  Sep 04, 2014


The Arctic research vessel Martin Bergmann temporarily ran aground early Wednesday morning in the Northwest Passage. The 19-metre vessel hit a sandy shoal in the Simpson Strait while travelling at low speed. It was dislodged within minutes. No damage or injuries were reported and the ship did not take on water.

"Only five to seven per cent of the Arctic is charted," said Adrian Schminowski, operations manager with the Arctic Research Foundation, which owns the Martin Bergmann. "That leaves a big hole in the Arctic of uncharted waters. Where we are operating, most of that area is uncharted.” The Martin Bergmann was travelling with the Canadian Coast Guard icebreaker Wilfrid Laurier.

In September 2010, a fuel tanker, the MV Nanny, also ran aground on a sandbar in the Simpson Strait. It was stuck for two weeks before enough of its diesel fuel cargo was pumped off to allow it to float off the sandbar.

latest june 2019 Jakobsson paper: http://oceanrep.geomar.de/46776/1/fmars-06-00283.pdf

wrote earlier that ESS bathymetry is from 1999 Russian Navy-supplied contour lines. They did not release  the survey lines, just the final product. Contours are a very different product from a DEM.

"Only a small fraction of the seafloor has been systematically mapped by direct measurement. The remaining bathymetry is predicted from satellite altimeter data, providing only an approximate estimation of the shape of the seafloor. Several global and regional initiatives are underway to change this situation. This paper presents a selection of these initiatives as best practice examples for bathymetry data collection, compilation and open data sharing as well as the Nippon Foundation-GEBCO”

"Despite collecting data for centuries and, in recent decades, the introduction of new and improved sounding techniques, the depth of the ocean has been determined over less than 18% of the seafloor using echo-sounders at a resolution of about 1 km (Mayer et al., 2018).”

"Multibeam echo-sounder systems became publically available in the 1970s), coincident with the development of the satellite-based navigation system global positioning system (GPS), enabling high spatial accuracy for environmental measurements globally. Multibeam systems radiate a fan of sound and listen to the returning echoes of the emitted signals in narrow sectors perpendicular to that fan, resulting in the mapping of a swath of seafloor instead of just a line. They have the advantage of collecting higher-resolution bathymetric data and of making mapping efforts much more efficient, by mapping an area in a much shorter time compared to SBESs. Modern systems can have many hundreds of beams and can achieve swath angles between 120 and 150 degrees. The area on the seafloor that an acoustic beam ensonifies is mainly dependent on beam widths of the transmit and receive beams, the opening angle chosen by the surveyor and the water depth. Small angles and shallow water depths generally result in smaller “acoustic footprints” and therefore higher-resolution data than large angles and deeper water depths, due to the expansion of the beam as it travels through the water column (Lurton, 2002). This means that very high-resolution data can be obtained using ships in shallow water, but that the resolution decreases with increasing water depth.

The first altimetric satellites were launched in the 1970s. Altimeters do not directly measure ocean depth, but the height of the ocean’s surface, which is affected, among other things, by the gravitational effects of topographic features on the seafloor. When the first satellite-altimetry derived digital terrain model (DTM) was first released it revolutionized the study of plate tectonics. Altimetry data have far lower horizontal resolution than ship’s bathymetry and provide depth estimates which are inherently under-determined. They can, however, reveal large geomorphological features of the ocean floor.

Modern multibeam echo-sounders have a size and power consumption that makes them suitable for autonomous operations. The use of autonomous surface vehicles (ASV) and autonomous underwater vehicles (AUV) equipped with such echosounders can release ships from dedicated mapping activities

Communication may still be limited by bandwidth and high costs restricting the transfer of the large volumes of data. An alternative strategy is to process data automatically on the vessel and create products that are small enough to be easily transferred over the available connection (e.g., Hamilton, 2018). Making data acquisition autonomous can also reduce safety risks by allowing operators to stay away from hazardous situations and still access traditionally inaccessible regions, e.g., under ice or navigationally complex areas, such as shallow waters, steep slopes or volcanic areas (e.g., Lucieer et al., 2016; Carlon, 2018). Furthermore, in deep water AUVs and remotely operated vehicles (ROV) can obtain multibeam data with a much higher resolution than ship-based systems”


Access to GMRT is provided through a web application called GMRT MapTool, several web services, and the java-based GeoMapApp desktop application. All of these tools and applications allow access to gridded elevation data in the form of grids, points, and profiles, as well as images and metadata information. Data can be extracted and downloaded from GMRT at user-defined resolutions in a variety of formats. Terrestrial and bathymetric

Published in April 2019, GEBCO’s latest grid, GEBCO_2019, is a global terrain model at 15 arc-second intervals which near the equator is about half a kilometer. GEBCO web map service (WMS). The GEBCO grid is available as a WMS, a means of accessing geo-referenced map images over the internet. – IHO-IOC GEBCO Cook Book

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #39 on: September 02, 2019, 06:39:03 PM »
Apologies for the high speed animation above. Due to the ezgif compression I can't easily slow it down without repeating the whole process again.

You can! Just use the 'back' button on your browser. :)
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #40 on: September 02, 2019, 06:41:56 PM »
Quote
"Only five to seven per cent of the Arctic is charted,"

 :'(
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #41 on: September 02, 2019, 07:10:30 PM »
Apologies for the high speed animation above. Due to the ezgif compression I can't easily slow it down without repeating the whole process again.
You can! Just use the 'back' button on your browser. :)
I'll try to remember that next time

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #42 on: September 02, 2019, 07:12:26 PM »
I'll try to remember that next time

*fingers crossed* ;)
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #43 on: September 03, 2019, 12:45:53 AM »
..

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #44 on: September 03, 2019, 05:42:19 PM »
75.12N 154.70, 107km NE of New Siberian Islands, 2000-2019. (same area as shoal pinball above)
cloud free days showing movement.
edit: replaced ani with a slower version
« Last Edit: September 03, 2019, 07:39:57 PM by uniquorn »

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #45 on: September 03, 2019, 08:50:43 PM »
Amazing!
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #46 on: September 03, 2019, 10:28:36 PM »
74.27N 152.41, 83km SE of NSI. Only visible (to me) in 2005, 2007 and 2016.
3 separate locations, will get the coords later.

uniquorn

  • Nilas ice
  • Posts: 1350
    • View Profile
  • Liked: 657
  • Likes Given: 119
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #47 on: September 04, 2019, 12:56:53 PM »
Here looking at interferometry on worldview to highlight stationary ice against movement. This example shows the ESS east of NSI, jun20-28 with 2day time lag
More on interferometry here: https://forum.arctic-sea-ice.net/index.php/topic,1259.msg143664.html#msg143664
makes a change from white

blumenkraft

  • Grease ice
  • Posts: 643
  • Fans of Hans Club - circa 2018
    • View Profile
  • Liked: 322
  • Likes Given: 407
Re: 'implausibly stationary ice' as a method of shoal discovery
« Reply #48 on: September 05, 2019, 06:49:48 PM »
https://en.wikipedia.org/wiki/Anchor_ice

Quote
Anchor ice is defined by the World Meteorological Organization as "submerged ice attached or anchored to the bottom, irrespective of the nature of its formation". It may also be called bottom-fast ice. Anchor ice is most commonly observed in fast-flowing rivers during periods of extreme cold, at the mouths of rivers flowing into very cold seawater, in the shallow sub or intertidal during or after storms when the air temperature is below the freezing point of the water, and the subtidal in the Antarctic along ice shelves or near floating glacier tongues, and in shallow lakes.
“You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.”