The 2022/2023 freezing season

[uniquorn]

smos thin ice thickness, oct6-8. Refreeze looks ok in the Laptev Sea, Pacific side has been delayed.
no data for oct9 yet
Could be it is still too warm for smos and that is surface water. Too cold for rain, maybe waves washing over freeboard.

[I’M IN LOVE WITH A RAGER]

It seems like the refreeze is kicking into the next gear, at least for now. I’m very curious to see what the effects of these late-season storms on the Pacific side may have (if any) in the long run. It seems like the Pacific seas have been at or above average in the first half of most recent melt seasons, and I wonder if that trend will continue to hold, or if we start to see a shift? I don’t think this season will necessarily be the thing to kick such a change off, but I wonder if an increase in end of season storms and mixing might lead to a trend in that direction over time.

[gerontocrat]

from NSIDC Sea ice Area 5-day Data

Below are graphs on the regions reluctant o refreeze

The Beaufort sea ice area continues to decrease though from a high level - now below tyhe 2010's average.

Refreeze has stalled in the Chukchi and the Canadian Archipelago, while refreeze is late starting in the Kara.

[uniquorn]

awi sic-leads v110, Beaufort and CAA, oct7-11. Looks like western Beaufort lost a few days freezing from the 955hPa low, no idea why McClure Strait was affected.

[FishOutofWater]

That intense storm drove a powerful surge in the intensity of the Alaskan coastal current. That current advects warm water from the Bering sea into the Beaufort sea north of Alaska's north slope. The location of the storm over relatively shallow water on the continental shelf prevented upwelling from the warm Atlantic water layer. Because of the Coriolis effect the longer term effects of this storm will be warming of upper layers of the Beaufort sea waters.

[uniquorn]

1. Thanks FOoW, it would be nice to verify any eventual warming but these are the only buoys available with active profilers. Would any of the 800m depth buoys show us more? Perhaps 136 and 122.

2. Buoy names

3. Looking at top7, near surface water has cooled since the warming event, either due bottom melt or drifting quite rapidly away from the main body of warmer Pacific layer.

4. It does look like there is some disruption to the lower winter layer but isn't that likely to cool the summer layer from below if they mix?
note they are different temp scales for 20m and 200m

[uniquorn]

smos thin ice thickness, oct6-8. Refreeze looks ok in the Laptev Sea, Pacific side has been delayed.
no data for oct9 yet
Could be it is still too warm for smos and that is surface water. Too cold for rain, maybe waves washing over freeboard.

Looks like it was either melt or high drift speed comparing oct7 to oct14
ani from oct1-14 for enthusiasts

[Niall Dollard]

Extent from Polar View (Russia is to the south) one week ago 8th Oct compared with extent today 15th (orange line).

Growth is extending from the Russian coast now.

[Tom Stedman]

Extent gains this time of the year are usually pretty high, until the Laptev freezes over.

[uniquorn]

The Nansen Environmental and Remote Sensing Center (nersc) nextsim forecasts now have  smaller formats. They include divergence, shear, sea ice concentration, sea ice thickness and  sea ice velocity. I think they are only available using an ftp client.
ftp.nersc.no/nextsimf/arctic_forecast_cmems.la10km

Here is today's shear forecast as an example.

[oren]

An AMSR2 animation of sea ice concentration in the central Arctic, courtesy of the Alfred Wegener institute (AWI). Note the Leads experimental product exaggerates the width of leads, in order to better show movement. More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

[oren]

A few regional charts of AMSR2 area courtesy of AWI and seaice.de, from the link https://sites.google.com/view/sea-ice/startseite, 2022 is represented by the white line.

Most regions show a nondescript season, close to the average, however the CAB is above average, and the CAA is relatively low.
Click to enlarge.

[oren]

4 more, due to attachment limit.
ESS is also above average.

[Jim Hunt]

The Nansen Environmental and Remote Sensing Center (nersc) nextsim forecasts now have  smaller formats.

Thanks for the heads up uniquorn.

[Jim Hunt]

The Alfred Wegener Institute has started publishing merged CryoSat-2/SMOS thickness data once again:

https://GreatWhiteCon.info/2022/10/facts-about-the-arctic-in-october-2022/#Oct-26

[oren]

An AMSR2 animation of sea ice concentration in the central Arctic, courtesy of the Alfred Wegener institute (AWI). Note the Leads experimental product exaggerates the width of leads, in order to better show movement. More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

Adding a chart of total AMSR2 area according to AWI, source https://sites.google.com/view/sea-ice/startseite

[oren]

With the very high area gains we had recently, one wonders where these gains are to be found and what sea is at high ice levels. Interestingly, the answer is all seas are on the early to average side but none is at record levels for the date.
CAB was relatively high but has stopped growing, now waiting for the "late" years to catch up.
CAA has grown rather sharply, and is on the high side.
Beaufort is slightly above the median for the date.
Chukchi is at the median.
Click all images to enlarge, 2022 is the white line.

[oren]

ESS enjoyed very high gains, and has reached "full" levels quite early (25th percentile).
Laptev also had large gains, very typical for its refreeze but a bit earlier than average (30th to 40th percentile).
Kara has recently started sharp gains but is actually below the median for the date.
The Greenland Sea is rather near record levels for the date, thanks to vigorous export recently which can be seen in the SIC-LEADS animation above.

Note some gains were also made by Barents and Baffin recently, though nothing fancy.

[uniquorn]

A few comments here and there saying the freezing season is boring. In a few years it might become the most interesting. Once the novelty of the next few record minimums pass, the processes of refreeze and ice thickening will likely become much more important to us. With that in mind here is another look at a 2020 research letter from some of the Mosaic scientists.

Platelet Ice Under Arctic Pack Ice in Winter
Christian Katlein, Volker Mohrholz, Igor Sheikin, Polona Itkin, Dmitry V. Divine, Julienne Stroeve, Arttu Jutila, Daniela Krampe, Egor Shimanchuk, Ian Raphael, Benjamin Rabe, Ivan Kuznetsov, Maria Mallet, Hailong Liu, Mario Hoppmann, Ying‐Chih Fang, Adela Dumitrascu, Stefanie Arndt, Philipp Anhaus, Marcel Nicolaus, Ilkka Matero , Marc Oggier, Hajo Eicken and Christian Haas
First published: 17 August 2020
https://doi.org/10.1029/2020GL088898

Abstract
The formation of platelet ice is well known to occur under Antarctic sea ice, where subice platelet layers form from supercooled ice shelf water. In the Arctic, however, platelet ice formation has not been extensively observed, and its formation and morphology currently remain enigmatic. Here, we present the first comprehensive, long‐term in situ observations of a decimeter thick subice platelet layer under free‐drifting pack ice of the Central Arctic in winter. Observations carried out with a remotely operated underwater vehicle (ROV) during the midwinter leg of the MOSAiC drift expedition provide clear evidence of the growth of platelet ice layers from supercooled water present in the ocean mixed layer. This platelet formation takes place under all ice types present during the surveys. Oceanographic data from autonomous observing platforms lead us to the conclusion that platelet ice formation is a widespread but yet overlooked feature of Arctic winter sea ice growth.

3 Results and Discussion
3.1 Subice Platelet Layer Morphology

We observed a 5 to 30 cm-thick subice platelet layer covering the ice bottom as shown in Figure 2. The ice platelets are composed of blade- or disc-shaped single ice crystals with c-axis alignment normal to the platelet surface. Most platelets were firmly attached to their substrate but fragile to physical impact by the ROV. When observed on ropes or chains, platelet ice crystals were tightly grown through their structure (Figures 2b and S4) and not just loosely attached to the respective surface. This indicates that these platelets grew on site and have not been advected in from deeper waters or horizontally as already suggested by Lewis and Lake (1971). Contrary to Antarctic fast ice, we did not find meter-thick layers of platelet ice accumulation (Hoppmann et al., 2017; Hunkeler et al., 2016), possibly due to slower platelet or faster congelation growth. The freezing front of the congelation ice quickly progressed downward into the subice platelet layer and incorporated it by congelation ice growth in between the platelet crystals (Dempsey et al., 2010). A thickness difference between Arctic and Antarctic subice platelet layers was already proposed by Lewis and Perkin (1986) based on different driving depths in the ice pump mechanism.
We identified crystal sizes up to approximately 15 cm from the ROV camera footage. Maximum crystal size retrieved with the towed zooplankton net was 9 cm, while the thicknesses of platelet crystals ranged from 0.8–2.5 mm. However, due to the limited size of the sampling bottle with a diameter of 10 cm and the physical interaction of the ROVnet (0.4 by 0.6 m opening) and platelet ice structures, platelets may well have been broken during the sampling process.

Platelet ice growth depends on available crystallization nuclei or seed crystals for secondary nucleation. Probably due to this reason, we did not observe platelet growth on the polymer-covered thermistor strings hanging in the water column. The complex structure of core-mantle polyamide rope or metal parts provided sufficient crystallization nuclei for platelet formation (Figures 2d and S4). Another explanation could be material-dependent adhesion of seed crystals as described in Robinson et al. (2020). This was particularly obvious on 15 February 2020, when the ROV had been hanging for 3 days in 2 m water depth and was covered in up to 30 mm large platelet crystals on edges and corners, while particularly smooth plastic surfaces were unaffected by platelet growth (Figure S5).

Text for the first image

Map of ice draft derived from multibeam sonar survey on 21 January 2020 with most prominent locations of the ubiquitous platelet ice observations (gray symbols), brinicles (light blue symbols), and ice core samples (red stars). White letters indicate the position of the ROV access hole (RC) and the MSS deployment hole (OC). Red letters refer to ice cores taken at the ROV site (R), the ice mechanics site (M), and the ridge site (F).

[uniquorn]

For something more recent, here is an attempt to look at the freezing point departures from WHOI TOP7 which show a similar pattern to that from the Mosaic expedition above but shallower, possibly due to the warm Pacific layer at ~50m.
https://www2.whoi.edu/site/itp/data/active-systems/top-07/
tech note: Freezing point was calculated using practical salinity. Probably should be using absolute salinity.

[oren]

Platelet Ice Under Arctic Pack Ice in Winter

Thank you uniquorn, very interesting.

[uniquorn]

That intense storm drove a powerful surge in the intensity of the Alaskan coastal current. That current advects warm water from the Bering sea into the Beaufort sea north of Alaska's north slope. The location of the storm over relatively shallow water on the continental shelf prevented upwelling from the warm Atlantic water layer. Because of the Coriolis effect the longer term effects of this storm will be warming of upper layers of the Beaufort sea waters.

Follow up on the Alaskan coastal current.

awi sic-leads v110. oct25-nov6
cmems sea water potential temp(near surface)
https://data.marine.copernicus.eu/-/d1ey4cflhl

[Brigantine]

The SMOS 50cm isopach now pretty closely resembles the extent (at / shortly before) minimum

[uniquorn]

SIMB3 565600 was deployed in the Beaufort Sea on sep26 and the ice beneath it continued bottom melt until oct6. At only 1m thick, ice cooling has been quite rapid and thickening probably started on oct28 but not really confirmed until nov3.

The top sounder is probably frosted since oct16 as the 2cm temp difference suggests there is roughly 6cm snow. The darker area below the ice line (at zero) is probably due to filling the deployment hole with snow from the refrozen water level to ice surface.
Note that when air temps rise to -10C(right hand scale) there is very little additional cooling from surface. Later in the season that heat flux will likely reverse at -10C. Similar to oct8.

This buoy is co-located with 3 others, WHOI TOP5 and ITP136 and AOFB flux buoy47

Interesting that the second thickening coincides with an increase in salinity detected by TOP5, possibly due to brine drainage. Some analysis of that on the buoy thread

Photo of the 4 buoys just after deployment by Elizabeth Bailey from the 2022 expedition of the Beaufort Gyre Exploration Project. More at the link.
565600 is 3rd from the left.

[oren]

An AMSR2 animation of sea ice concentration and movement in the central Arctic, courtesy of the Alfred Wegener institute (AWI). More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

Adding a chart of total AMSR2 area according to AWI, source https://sites.google.com/view/sea-ice/startseite

[uniquorn]

When you say old you mean it is not caused by any recent event?

Yes. The mixing to surface is probably related to the recent low pressure event but 2.2C water at 50m is probably pacific summer water. As modelled by Mercator its main entry points to the Beaufort are near Barrow Canyon where it is warmest and north of the Northwind Ridge as shown in the high contrast 34m temperature image.
Ocean gyre circulation suggests BC for TOP7 location.

With another strong southerly forecast over Chukchi at 74km/h in 2days, further investigation using cmems mercator at 50m does model warm water pushed around the Northwind Ridge from the west. It arrives later than oct7 though, so warm water drifting from Barrow Canyon some time earlier still looks the most likely source for the eddy.

The forecast for this event is another pulse eastwards along the Alaskan coast, though cooler this time. Note also the cool Siberian current being forced northwards.

The Operational Mercator global ocean analysis and forecast system at 1/12 degree is providing 10 days of 3D global ocean forecasts updated daily. The time series is aggregated in time in order to reach a two full year’s time series sliding window.

This product includes daily and monthly mean files of temperature, salinity, currents, sea level, mixed layer depth and ice parameters from the top to the bottom over the global ocean. It also includes hourly mean surface fields for sea level height, temperature and currents. The global ocean output files are displayed with a 1/12 degree horizontal resolution with regular longitude/latitude equirectangular projection.

50 vertical levels are ranging from 0 to 5500 meters.

This product also delivers a special dataset for surface current which also includes wave and tidal drift called SMOC (Surface merged Ocean Current).

DOI (product):
https://doi.org/10.48670/moi-00016

my emphasis

https://data.marine.copernicus.eu/-/wdxate6fdl

[uniquorn]

A closer look at the Alaskan current using rammb reveals a large eddy centred roughly on 71.5N -149 along the shelf break where the two currents meet. 200km east of the Barrow Canyon exit. I don't yet know how permanent it is.

https://col.st/NJnrH  nov12-14
https://go.nasa.gov/3TSMayB
https://www.gmrt.org/GMRTMapTool/np/

cmems temperature at 12m depth shows more movement in the Alaskan coastal current.
https://data.marine.copernicus.eu/-/nt5wrnbpam
would clog up the thread to keep posting mp4's here

[uniquorn]

overview since sep30 using awi sicleads v110 overlaid onto ascat, 16MB.
sic-leads nov11-12 not available

[Brigantine]

NSIDC ARCTIC SEA ICE AREA (5-day trailing average): A bit more

Something odd is happening in the Beaufort and Chukchi regions.

Beaufort sea ice area on this day is lowest in the satellite record for the first time this year after being at a very high level just 10 days ago.

The Chukchi sea ice area is currently 3rd lowest in the satellite record.

As all good stories leave you with - "What happened next?.....

One of those times when Barrow is as warm as Kentucky:
(Which is cause and which is effect?)

[SimonF92]

Strong northerlies from tomorrow probably going to help extent back up into the pack

[johnm33]

Something odd is happening in the Beaufort and Chukchi regions.

Just an idea, since the channel Mclure/Lancaster cleared it looks like there's a flow pushing through from Baffin, enough to interfere with the 'natural' flow of incoming Pacific waters to the east. So these waters are being forced out further on both sides of Chukchi rise. Taken together with the influx from the Atlantic precipitated by the mslp set up around the mid october full moon, which increased outflows through Fram, and those enhanced by the subsequent general high pressure over the whole ocean the co-incidence of opposite tidal forcings at Fram and Bering have increased an already established general movement Fram-ward between the two, this allows the tidal pulses delivered throuh Bering to be larger and penetrate further creating the apparent vortice-like perimeter of the ice, as seen on AMSR2, and subsequent warming/mixing.

[uniquorn]

Record Beaufort low extent for the time of year due to a combination of the forecast increase flow of the warmer Alaskan coastal current and warm southerlies. Chukchi open water is not so unusual but maybe some more mixing due to the milder cyclone around nov18 following a similar path to the previous record low on oct7.
Drift west of Mclure probably wind driven.
High vorticity likely causing mixing along the Beaufort/Chukchi shelf break visible both east and west of Barrow Canyon. Looks like the warmer Pacific water is taking longer to sink.

Yep, refreeze is coming. Just another short delay.

1. awi jaxa/amsr2 v110 Beaufort Extent. Note the 2021 regional ice mask
https://sites.google.com/view/sea-ice/startseite

Reference for regional ice mask

Meier, W.N., J.S. Stewart, A. Windnagel, and F.M. Fetterer, 2022. Comparison of Hemispheric and Regional Sea Ice Extent and Area Trends from NOAA and NASA Passive Microwave-Derived Climate Records, Rem. Sens., 14, 619, doi:10.3390/rs14030619. https://www.mdpi.com/2072-4292/14/3/619

2. nullschool nov18

3. awi sic-leads v110 and gmrt bathy, nov 16-21

4. nearest polarview S1A nov19

[gerontocrat]

Now the DMI have got their North of 80 Data up and running again Nico Sun's graph from https://cryospherecomputing.com/ can show what happened to temperatures North of 80 over the last week or two - it got cold

Climate reanalyser's 5 day average temps forecast suggests that the Central Arctic from Russia to the CAA will stay cold, but with warmer than average temps in the Western Chukhci / Beaufort and in The Atlantic Front.

We might see some big contrasts in freezing season progress in the various regions of the Arctic over the next few days.

click images to enlarge

[Paul]

I expect as the Chukchi sea freezes over in the short term, the Beaufort anamoly will reduce(remember the models are forecasting conditions as of now so it won't factor in refreeze in the longer range temperatures) however I'm not expecting the same over the Barants and to a lesser extent the Kara sea. Temperatures are set to remain above average with largely unfavourable sea ice growth weather. There could be some localised growth in the Kara sea but there will still be open water as we head into December in noticetable quantities.

The CAB in general looks like it will be below average for the foreseeable and we could see some impressive below average temperatures across Asia. Strong hints of the PV splitting will enhance this also.

All in all, despite the lack of ice in the Barants and kara seas, its not another 2016 fall season.

[oren]

An AMSR2 animation of sea ice concentration and movement in the central Arctic, courtesy of the Alfred Wegener institute (AWI). More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

Adding a chart of total AMSR2 area according to AWI, source https://sites.google.com/view/sea-ice/startseite

[uniquorn]

A closer look at the Alaskan current using rammb reveals a large eddy centred roughly on 71.5N -149 along the shelf break where the two currents meet. 200km east of the Barrow Canyon exit. I don't yet know how permanent it is.

https://col.st/NJnrH  nov12-14
https://go.nasa.gov/3TSMayB
https://www.gmrt.org/GMRTMapTool/np/

cmems temperature at 12m depth shows more movement in the Alaskan coastal current.
https://data.marine.copernicus.eu/-/nt5wrnbpam
<>

A quick follow up on Alaskan coastal eddies. The large cyclonic eddy above moved west and appears to be dissipating at surface. Another smaller but stronger anticyclonic eddy is now visible at 71.6N -151.6.
Shows up well on awi sic-leads v110, nov21-24

[uniquorn]

As noted up thread, attention may shift to the Atlantic side with southerlies forecast to reach deep into the pack.

[gerontocrat]

As noted up thread, attention may shift to the Atlantic side with southerlies forecast to reach deep into the pack.

GFS seems to agree.

Nico Sun's adapted DMI North of 80 graph (@ https://cryospherecomputing.com/) shows temperatures North of 80 to be really, really cold.
The GFS 3 day temp forecast shows a band of really cold air from the Russian to the Canadian shore with high -ve temp anomalies, as will be Alaska and most of Canada. The 250 HPA map perhaps shows why?

However, the Chukchi and Beaufort (Pacific Gateway) are warmer than average, even more so on the entire Atlantic Front and Greenland. Also GFS forecasts show that later +ve temp anomalies will creep into the Central Arctic with the +ve anomalies intensifying both in the Pacific Gateway and especially the Atlantic Front and Greenland which may well see some unusual late coastal melt. (No images as GFS has a habit of changing its mind beyond 3 or 4 days.)

This freezing season may still have some surprises in store

click images to enlarge

[uniquorn]

Alaskan coastal eddy is still visible on amsr2 sic-leads nov24-28. Anticyclonic is perhaps upwelling warmer water from below.

https://go.nasa.gov/3u7Knv0

[oren]

A post by Vox_Mundi in the what's new in the Arctic thread brings us back to an ASIF discussion from Jan 2022. Copying it here for wider visibility as I think the study is very interesting.

Study Shows That Strongest Arctic Cyclone On Record Led to Surprising Loss of Sea Ice
https://phys.org/news/2022-11-strongest-arctic-cyclone-loss-sea.html

The strongest Arctic cyclone ever observed poleward of 70 degrees north latitude struck in January 2022 northeast of Greenland. A new analysis led by the University of Washington shows that while weather forecasts accurately predicted the storm, ice models seriously underestimated its impact on the region's sea ice.





The study, published in October in the Journal of Geophysical Research: Atmospheres, suggests that existing models underestimate the impact of big waves on ice floes in the Arctic Ocean.

"The loss of sea ice in six days was the biggest change we could find in the historical observations since 1979, and the area of ice lost was 30% greater than the previous record," said lead author Ed Blanchard-Wrigglesworth, a research assistant professor of atmospheric sciences at the UW. "The ice models did predict some loss, but only about half of what we saw in the real world."

The January 2022 cyclone had the lowest pressure center estimated since satellite records began in 1979 above 70 degrees north (January 24 - 932.2 mb at 79.5°N 20°E.). It was an extreme version of a typical winter storm. Climate change doesn't appear responsible for the cyclone: The researchers didn't find a trend in the strength of intense Arctic cyclones since 1979, and sea ice area was close to the historical normal for that region before the storm hit.

During the storm, record winds howled over the Arctic Ocean. The waves grew to 8 meters (26 feet) tall in open water and remained surprisingly strong as they traveled through the sea ice. The ice heaved 2 meters (6 feet) up and down near the edge of the pack, and NASA's ICESat-2 satellite shows that the waves reached as far as 100 kilometers (60 miles) toward the center of the ice pack.

Six days after the storm struck, the sea ice had thinned significantly in the affected waters north of Norway and Russia, in places losing more than half a meter (about 1.5 feet) of thickness.





The new analysis shows that the atmospheric heat from the storm had a small effect, meaning some other mechanism was to blame for the ice loss. Possibilities, Blanchard-Wrigglesworth suggests, include sea ice that was thinner before the storm hit than models had estimated; that the storm's waves broke up ice floes more forcefully than models predicted as they penetrated deep into the ice pack; or that waves churned up deeper, warmer water and brought it into contact with the sea ice, melting the ice from below.



The unexpected ice loss, despite an accurate storm forecast, suggests that this is an area where models could improve.

Edward Blanchard‐Wrigglesworth et al, Record Arctic Cyclone of January 2022: Characteristics, Impacts, and Predictability, Journal of Geophysical Research: Atmospheres (2022)
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JD037161

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

The ASIF discussion starts at: https://forum.arctic-sea-ice.net/index.php/topic,3648.msg330257.html#msg330257

[oren]

An AMSR2 animation of sea ice concentration and movement in the central Arctic, courtesy of the Alfred Wegener institute (AWI). More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

Adding a chart of total AMSR2 area according to AWI, source https://sites.google.com/view/sea-ice/startseite

[Glen Koehler]

     I know the estimated volume of ice exported out of the Arctic basin via the Nares strait is relatively small compared to the total ASI volume, that appearances can be deceiving, and that there have been previous years where the Nares Strait stayed open all year. 

     But it sure looks like the Nares is a bleeding wound weakening the accumulation of ASI from the heart of the "Last ice area" and ultimately lowering the end of melt season volume next September.

[uniquorn]

A recent paper studying Petermann Glacier provided us with Nares Strait water temperatures from 1963-2021. The right hand chart shows the change in temperature averaged between 350m-450m depth. Incoming water from the north at that depth has to rise to less than 200m to enter from the west side of the Lincoln Sea.

The increase in water temp looks to be roughly 0.25C

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
Published: 08 Aug 2022
The Cryosphere, 16, 3021–3031, 2022   
https://doi.org/10.5194/tc-16-3021-2022

fig5
ibcao bathy(high contrast) and https://go.nasa.gov/3UjqEmM

[binntho]

The increase in water temp looks to be roughly 0.25C

To me it looks closer to 1C at the surface, and fairly constant 0.5C below that?

[uniquorn]

The increase in water temp looks to be roughly 0.25C

To me it looks closer to 1C at the surface, and fairly constant 0.5C below that?

Possibly, though the middle chart is messy.

Quoting from the paper above:

3.4 Ocean thermal forcing

We reconstruct the history of ocean thermal forcing by compiling conductivity, temperature, and depth (CTD) measurements from the Hadley Centre (https://bodc.ac.uk, last access: February 2022) within Petermann fjord and Nares Strait, spanning from 1960 to 2019, combined with CTD from NASA's Ocean Melting Greenland Earth Venture Suborbital mission from 2016–2021 (Fenty et al., 2016). 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. Overall ocean temperature in the fjord at 350–450 m depth (the maximum grounding line depth is ∼ 500 m) is > 0.3 ∘C warmer in the 2020 than in the 1970s–1980s. This warming signal has been documented elsewhere with a change in temperature of 0.23 ∘C between 2003 and 2009 (Washam et al., 2018).

We might ask ourselves how the 400m depth water gets into the Nares Strait.
  It's warmer than surface waters so it must be more saline. The current is from the north so it is likely to be either deeper waters returning from the northern basins or WSC waters making their way around northern Greenland somehow.
The comparison of ice distribution and bathymetry suggests to me that some of the deeper northern waters are forced up the shelf break closer to the surface on the western side of the Lincoln Sea. Some probably take the easier path through the deeper channel on the eastern side and we see little effect from above. The majority is likely forced towards the Fram Strait by the bathymetry.
Note that water can also occasionally enter Nares Strait from the south.


https://col.st/ypPsF nov30-dec1

[kassy]

JAXA ARCTIC SEA ICE EXTENT:  10,142,015 KM2 as at 01-Dec-2022

- Extent loss on this day 64k which is 131 k less than the average gain on this day (of the last 10 years) of 67k,

...

A sea ice loss this large in the middle of the freezing season does not happen very often. If it is followed by more losses it would be rare to unique

We will know more tomorrow but it´s probably wind driven so it might just depend on that?

[uniquorn]

Polar vortex forecast, nh, dec5-8
https://stratobserve.com/misc_vort3d

[El Cid]

GFS shows a sudden stratospheric warming peaking Dec 9-Dec 15. No split in the vortex is seen yet. In my (admittedly pretty short) experience SSW and p.vortex split is more important for NH midlatitude winter weather (especially N. America) than the Arctic though...

...however the current extent numbers are quite amazing: 2022 climbed to 4th place, behind 2016,2020 and 2006 only (a few days ago it was still below the 2010s average value)

[oren]

An AMSR2 animation of sea ice concentration and movement in the central Arctic, courtesy of the Alfred Wegener institute (AWI). More information available in the AWI thread mostly updated by uniquorn.
Click to animate and click again for maximum resolution.
Source is mirrored on https://seaice.de/AMSR2_Central_Arctic_SIC-LEADS.gif

Adding a chart of total AMSR2 area according to AWI, source https://sites.google.com/view/sea-ice/startseite

And DMI temps N of 80, for what it's worth.

[oren]

With the the sudden slowdown in ice growth, it is worthwhile to look at the various regions using AWI's AMSR2 data. Note 2022 is always the white line, click to expand.
The CAB, Kara, Barents and Greenland Sea all show drops, each is within normal variability but coupled together bring about a significant shift in the rankings.