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uniquorn

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CryoSat-SMOS Merged Sea Ice Thickness
« on: December 06, 2021, 01:56:21 PM »
https://spaces.awi.de/display/CS2SMOS/CryoSat-SMOS+Merged+Sea+Ice+Thickness

Quote
Changelog
Fall 2021 Update (v2.4)

Input Data

    CryoSat-2 ICE baseline E data as primary altimeter data now used for the operational near real-time and reprocessed data generation from October 2021 and later. The previous data record (Nov 2010 till April 2021) is based on the previous L1B version (ICE baseline D).

Auxiliary Data

    Updated C3S sea ice type (interim) climate data record from version 1 to version 2 (reprocessed data only).
    Updated OSI-SAF operational sea ice type to version OSI-403-d.
    Updated mean sea surface from DTU15 to DTU21.

Algorithm

    Surface type classification: Sea ice mask is now based on 15% sea ice concentration threshold. The threshold was 70% in previous versions.
    Used `uncertainty´ field in OSI-403-d sea ice type files instead of parametrization based on `confidence` flags of previous versions.
    The sea ice thickness quality flag is no longer automatically set to ‘intermediate’ outside the central Arctic basin.

Product format and content

    Flag values of the status flag (l3c variable `status_flag`) have been changed. Flag value 0 is now `nominal` and other values have been shifted accordingly.
    Flag values of the quality flag (l3c variable `quality_flag`) have been changed. Flag value 0 is now `nominal` and the ‘no data’ has been moved to flag value 3.
    Various changes to the global and variable attributes to improve compliance with newer versions of the Climate & Forecast (CF) and Attribute Convention for Dataset Discovery (ACDD) standards.

Level-1 Pre-Processor

    Added L1 preprocessor for CryoSat-2 L1b for ICE baseline-E.

Points of Contacts
cs2smos-support@awi.de
Responsible Scientists
Robert Ricker, Stefan Hendricks, Xiangshan Tian-Kunze, Lars Kaleschke

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #1 on: December 06, 2021, 02:03:40 PM »
1. Animation of v204 near real time .nc files using panoply diff32 palette limited from 0m to 4m
oct21-dec3 (5.5MB)

2. Interesting small negative anomaly on nov5
« Last Edit: December 06, 2021, 02:12:05 PM by uniquorn »

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #2 on: December 06, 2021, 03:36:32 PM »
some history with volume(2010-2018)
https://spaces.awi.de/pages/viewrecentblogposts.action?key=CS2SMOS
Robert Ricker (20MB)
I've added a pause

Jim Hunt

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #3 on: December 06, 2021, 03:43:38 PM »
"The most revolutionary thing one can do always is to proclaim loudly what is happening" - Rosa Luxemburg

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #4 on: December 06, 2021, 03:48:57 PM »
Sorry Jim, I knew there was a thread somewhere but didn't think to look in dev.

Jim Hunt

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #5 on: December 06, 2021, 03:57:10 PM »
The topic is worthy of a more "mainstream" venue as well!

When I have a spare 5 minutes I'll see if can distinguish FYI from MYI.
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oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #6 on: December 12, 2021, 11:21:42 PM »
Thanks a lot for the above animations and information.

nadir

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #7 on: January 06, 2022, 04:44:57 PM »
Posting here the most recent chart by Zach Labe (grabbed it from his website https://sites.uci.edu/zlabe/arctic-sea-ice-volumethickness/ )

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #8 on: January 20, 2022, 10:38:36 AM »
1. Animation of v204 near real time .nc files using panoply diff32 palette limited from 0m to 4m
oct21-jan17 (11.2MB)

2. Interesting small negative anomaly on jan2

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #9 on: January 29, 2022, 10:02:54 PM »
Animation of v204 near real time .nc files using panoply diff32 palette limited from 0m to 4m
oct21-jan27 (12.8MB)

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #10 on: February 17, 2022, 10:19:04 PM »
Animation of v204 near real time .nc files using panoply diff32 palette limited from 0m to 4m
oct21-feb15 (15.6MB)

Tor Bejnar

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #11 on: February 18, 2022, 04:21:26 PM »
It might be interesting to overlap this ice thickness animation with an ice drift animation (such as found on the Nares Thread). 

The late (in the above animation) ice thinning in southern Lincoln Sea (white to yellow), for example, is associated with the active Nares Strait "funnel".  The thickening area north of Greenland, on the other hand, appears not to move (just thicken), even as Fram-beckoned ice passes by.  (I can 'see' the dynamic of ice thickening as it reaches the north-of-Greenland area, then statistically thinning (by addition of leads) as it approaches Fram Strait.)
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #12 on: March 08, 2022, 10:40:07 PM »
good idea, maybe in april when it closes down for the summer.

Animation for feb1-mar6 (5MB)

vox_mundi

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #13 on: March 10, 2022, 07:21:18 PM »
New Observations From ICESat-2 Show Remarkable Arctic Sea Ice Thinning In Just Three Years
https://phys.org/news/2022-03-icesat-remarkable-arctic-sea-ice.html

Over the past two decades, the Arctic has lost about one-third of its winter sea ice volume, largely due to a decline in sea ice that persists over several years, called multiyear ice, according to a new study. The study also found sea ice is likely thinner than previous estimates.

Arctic sea ice snow depth is estimated, for the first time, from a combination of lidar (ICESat-2) and radar (CryoSat-2) data. Using these estimates of snow depth and the height of sea ice exposed above water, the study found multiyear Arctic sea ice has lost 16% of its winter volume, or approximately half a meter (about 1.5 feet) of thickness, in the three years since the launch of ICESat-2.

"We weren't really expecting to see this decline, for the ice to be this much thinner in just three short years," said lead study author Sahra Kacimi, a polar scientist at the California Institute of Technology's Jet Propulsion Laboratory.

Scientists make satellite estimates of sea-ice thickness using snow depth and the height of the floating ice above the sea surface. Snow can weigh ice down, changing how ice floats in the ocean. The new study compared ice thickness using new snow depths from satellite radar and lidar to previous ice thickness and snow depth estimates from climate records. The researchers found using climatology-based estimates of snow depth can result in overestimating sea-ice thickness by up to 20%, or up to 0.2 meters (0.7 feet).

The study used an 18-year record of sea-ice observations from ICESat and the newer ICESat-2 and CryoSat-2 satellites to capture monthly changes in Arctic sea-ice thickness and volume, to provide context for sea ice thickness estimates from 2018 to 2021. The 18-year record showed a loss of about 6,000 cubic kilometers of winter ice volume, largely driven by the switch from predominantly multiyear ice to thinner, seasonal sea ice.

Older, multiyear ice tends to be thicker and therefore more resistant to melting. As that "reservoir" of old Arctic sea ice is depleted and seasonal ice becomes the norm, the overall thickness and volume of Arctic sea ice is expected to decline. "Current models predict that by the mid-century we can expect ice-free summers in the Arctic, when the older ice, thick enough to survive the melt season is gone," Kacimi said.

"This is really old ice we're losing at quite a frightening rate," Mallett said.

Sahra Kacimi et al, Arctic snow depth, ice thickness and volume from ICESat‐2 and CryoSat‐2: 2018‐2021, Geophysical Research Letters (2022)
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097448
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uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #14 on: March 31, 2022, 12:31:28 AM »
It might be interesting to overlap this ice thickness animation with an ice drift animation (such as found on the Nares Thread).<>
Animation of v204 near real time .nc files using panoply diff32 palette limited from 0m to 4m, AWI LEADS overlaid, colour inverted, and white set to transparent (20MB)
oct21-mar28, small
maybe a bit heavy on the leads
« Last Edit: March 31, 2022, 12:38:14 AM by uniquorn »

oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #15 on: March 31, 2022, 08:44:19 AM »
A great animation, truly. The movements shown by Leads affect thickness distribution as measured by CS2SMOS, this is best shown near the Fram.
One can also see how the Barents storms pushing the ice edge into the northern Kara increase the thickness of the ice against Novaya Zemilya due to compaction even while reducing extent.

Tor Bejnar

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #16 on: March 31, 2022, 07:43:44 PM »
Thank you so much Uniquorn!  The Lincoln Sea thinning due to Kane export is apparent [as was 'obvious' previously].  A couple of the thickest (final) ice locations have apparent cessations of drift movement during the animation (north of Greenland [a surprise to me] and north of the Canadian Arctic Archipelago [CAA - not a surprise to me).

The 'over-emphasized' leads were just right, from my point-of-view.
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

gerontocrat

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #17 on: March 31, 2022, 09:46:22 PM »
New Observations From ICESat-2 Show Remarkable Arctic Sea Ice Thinning In Just Three Years
https://phys.org/news/2022-03-icesat-remarkable-arctic-sea-ice.html

The study used an 18-year record of sea-ice observations from ICESat and the newer ICESat-2 and CryoSat-2 satellites to capture monthly changes in Arctic sea-ice thickness and volume, to provide context for sea ice thickness estimates from 2018 to 2021. The 18-year record showed a loss of about 6,000 cubic kilometers of winter ice volume, largely driven by the switch from predominantly multiyear ice to thinner, seasonal sea ice.

Sahra Kacimi et al, Arctic snow depth, ice thickness and volume from ICESat‐2 and CryoSat‐2: 2018‐2021, Geophysical Research Letters (2022)
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097448

Interestingly enough, the PIOMAS data for the April Monthly Average (i.e. month of maximum volume) shows a 4.75 thousand KM3 volume loss for the 18 years from 2003 to 2021.

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uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #18 on: October 28, 2022, 03:26:53 PM »
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

No details on v205 yet at https://spaces.awi.de/display/CS2SMOS/CryoSat-SMOS+Merged+Sea+Ice+Thickness.

Did find this though

Monitoring Arctic thin ice: A comparison between Cryosat-2 SAR altimetry data and MODIS thermal-infrared imagery

Felix L. Müller, Stephan Paul, Stefan Hendricks, and Denise Dettmering
Preprint. Discussion started: 24 May 2022
https://tc.copernicus.org/preprints/tc-2022-98/tc-2022-98.pdf

Quote
Abstract.
Areas of thin sea ice in the polar regions are not only experiencing the highest rate of sea-ice production but are, therefore, also important hot spots for ocean ventilation as well as heat and moisture exchange between the ocean and the atmosphere. Through co-location of
  (1) Moderate Resolution Imaging Spectroradiometer (MODIS) derived thin-ice thickness estimates with
  (2) an unsupervised waveform classification (UWC) approach and
  (3) Sentinel-1 A/B SAR reference data, thin-ice based waveform shapes are identified, referenced, and discussed with regard to a manifold of waveform shape parameters.
  Here, a strong linear dependency is found that shows the possibility to either develop simple correction terms for altimeter ranges over thin ice or to directly adjust current retracker algorithms specifically to very thin sea ice. This highlights the potential of CryoSat-2-based SAR altimetry to reliably discriminate between thick sea ice, open-water leads, as well as thin-ice occurrences within recently refrozen leads or mere areas of thin sea ice. Furthermore, a comparison to the ESA Climate Change Initiative’s (CCI) surface-type classification reveals that the newly found thin-ice related waveforms are divided up almost equally between ’unknown’ (46.3 %) and lead-type (53.4 %) classifications. Overall, the UWC results in far fewer ’unknown’ classifications (1.4 % to 38.7 %). Thus, UWC provides more usable information for sea-ice freeboard and thickness retrieval while UWC at the same time reduces range biases from thin-ice waveforms processed as regular sea ice in the CCI classification.
« Last Edit: October 28, 2022, 06:55:18 PM by uniquorn »

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uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #20 on: November 03, 2022, 11:01:27 PM »
v205 changelog
https://spaces.awi.de/display/SIRAL/Version+History

Quote
Changelog
Fall 2022 Update (v2.5)

Input Data

    Open Ocean data from CryoSat-2 pulse-limited radar mode (LRM) is included, but not yet used for estimation of sea surface height

Auxiliary Data

    Update region code to 2021 NSIDC regional mask for Arctic sea ice trends and climatologies (credit J. Scott Stewart and Walter N. Meier, NSIDC)

Algorithm

    New surface type classification (sea ice / lead / open ocean discrimination). The new surface type classification increases the number of waveforms for sea ice freeboard/thickness evaluation.
    New flag indicating surface wave / swell influence in the marginal ice zone. Surface waves that penetrate into the sea ice lead to a roughening of the surface and a freeboard bias. This bias is now detected based on waveform properties and the distance to open water from sea ice concentration data.
    Quality flag (l3c variable `quality_flag`) now also depends on marginal ice zone flag

Product format and content

    Quality flag (l3c variable `quality_flag`) now also depends on marginal ice zone flag
    Added coverage_content_type  attribute to all netCDF variables
    Minor update of global attributes

Fixed Issues

    Date in L2P files was incorrect in version 2.4 in cases where the first orbit included data from a previous day. In this case the L2P file from the previous file was overwritten resulting in data loss.
    Fixed issue with connecting data from the same orbit that was distributed over different files in Level-1 pre-processor. The issue has caused data loss and degraded sea surface height information (see https://github.com/pysiral/pysiral/issues/91)
    Fixed issue with computing pulse peakiness for noisy waveforms in Level-1 pre-processor. This issue has caused incorrect surface type classifications (https://github.com/pysiral/pysiral/issues/89)

Known Issues

    Sea ice type auxiliary data set for reprocessed CryoSat-2 (OSI-SAF/C3S sea ice type climate data record only contains ambigous ice types in the first half of October. This leads to a sudden change of the snow depth and density parametrization and a change in sea ice thickness on October 16). The OSI-SAF operational sea ice type product is not affected.
    The marginal ice zone flag may include LRM waveforms over open water.
« Last Edit: November 03, 2022, 11:39:11 PM by uniquorn »

oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #21 on: November 04, 2022, 12:32:56 AM »
Quote
2021 NSIDC regional mask
Interesting. It seems to be similar to the CT regions map (which I personally prefer), at least looking at Beaufort and Chukchi. But is NSIDC using the updated map in its regional extent/area? I think not (yet?)

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #22 on: November 04, 2022, 04:18:18 PM »
I hadn't noticed that awi amsr2 v110 is already using the NSIDC 2021 mask.

From the README_v110
Quote
Regional sea ice extent and area v110
Regional sea ice extent and area are calculated based on the new NSIDC regional mask for Arctic sea ice trends and climatologies [10].
For the southern hemisphere we follow the regional definition as used in Parkinson and Cavalieri (2012).
<>
[10] J. Scott Stewart and Walter N. Meier, Regional mask for Arctic sea ice trends and climatologies (version 2021), NSIDC,
https://insidecires.colorado.edu/rendezvous/uploads/Rendezvous_2021_1448_1619668996.pdf

gerontocrat

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #23 on: November 04, 2022, 11:24:28 PM »
Quote
2021 NSIDC regional mask
Interesting. It seems to be similar to the CT regions map (which I personally prefer), at least looking at Beaufort and Chukchi. But is NSIDC using the updated map in its regional extent/area? I think not (yet?)
It is absolutely certain that the sea ice boundaries used by NSIDC in the area/extent regional tables published on https://nsidc.org/arcticseaicenews/sea-ice-tools/ HAVE NOT CHANGED. And those are the boundaries I use in all my analyses (apart from PIOMAS (and HYCOM?) data from Steven.

The Central Arctic Region boundary with the Beaufort, Chukchi, ESS, Laptev, Kara nd Greenland regions sort of follow the 80 North latitude. I think that is good, as 80 North is the the summer ice edge that is increasingly being breached, apart from the Atlantic Front (Greenland and Kara and now in many years the Laptev where the summer ice edge somrtimes approaches and even breaches 85 North).

I attach the map / table showing the differences between the NSIDC & the Wipneus (looks like CT) boundaries .
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uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #24 on: November 08, 2022, 06:50:32 PM »
panoply generated CS2-SMOS merged sea ice thickness with awi v110 leads.
oct21-nov6

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #25 on: November 10, 2022, 09:27:40 AM »
Interesting. The thickest ice is not exactly where I thought it should be somewhat nearer to the CAA/Ellesmere. I also note some of it is on the verge of Fram export.

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #26 on: November 10, 2022, 12:21:17 PM »
model vs measurement, both have known issues
latest hycom cice thickness without forecast

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #27 on: December 28, 2022, 11:29:25 AM »
All v205 data is available via FTP: ftp.awi.de/sea_ice/product/cryosat2_smos/v205/nh/

I'm not a Python expert, so thanks are due to both Wipneus and Stefan Hendricks for their contribution to the attached source code. Thanks also to Christian for the inspiration.

I played around with Jim Hunt's python script and modified it to calculate daily regional volume.  In the calculations, I used the regional mask in the CryoSat auxiliary data (h/t uniquorn):



Attached is a spreadsheet with the calculated daily regional volume data from Nov 2010 to Dec 2022.

Steven

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #28 on: December 28, 2022, 11:35:46 AM »
Here are plots of the results:

(click images to enlarge)

Beaufort:


Chukchi:


ESS:


Laptev:


Central Arctic:


Kara:
https://i.imgur.com/jYDDBHV.png

Barents:
https://i.imgur.com/kOulvQx.png

Greenland Sea:
https://i.imgur.com/CShtsLp.png

Canadian Archipelago:
https://i.imgur.com/VbcqeCu.png

Baffin Bay:
https://i.imgur.com/gNpYZA9.png

Hudson Bay:
https://i.imgur.com/YUGXnml.png

Bering:
https://i.imgur.com/oXnvSKL.png

Okhotsk:
https://i.imgur.com/Qc5rPNG.png

Jim Hunt

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #29 on: December 30, 2022, 10:12:05 AM »
I played around with Jim Hunt's python script and modified it to calculate daily regional volume.  In the calculations, I used the regional mask in the CryoSat auxiliary data (h/t uniquorn):

Thanks very much Steven. Could you upload the modified code to the thread in the Developers Corner?
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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #30 on: December 30, 2022, 05:51:08 PM »
Could you upload the modified code to the thread in the Developers Corner?

Comment added:
https://forum.arctic-sea-ice.net/index.php/topic,3000.msg355033.html#msg355033

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #31 on: January 02, 2023, 05:56:04 PM »
The Laptev Sea had some huge spikes in sea ice thickness in December, but they have more or less disappeared in the last few days.  Probably a CryoSat artifact of some kind rather than real pressure ridges?


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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #32 on: January 02, 2023, 06:01:45 PM »
The rate of growth in early December does seem unphysical.

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #33 on: January 02, 2023, 06:16:45 PM »
Trying out a different kind of visualization, using a 3D plotting tool (rayshader):

Here is an animation of the freezing season so far, at 10-day intervals, from mid October to late December.  Sea ice is shown as brown "mountains" with shadows, and everything else as flat blue terrain.

This also shows the CryoSat thickness spikes in Laptev Sea appearing in December, and disappearing again in the final frame.


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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #34 on: January 02, 2023, 06:52:47 PM »
The rate of growth in early December does seem unphysical.

Probably.  On the other hand, PIOMAS too shows strong volume growth in Laptev Sea in the first half of December 2022, but not as extreme as CryoSat.  There was an unusual weather pattern in the first half of December, compressing the sea ice against the Western coast of Laptev Sea, so perhaps also some real pressure ridges there.

binntho

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #35 on: January 03, 2023, 03:26:13 AM »
Trying out a different kind of visualization, using a 3D plotting tool (rayshader):

That's actually a very good visualisation tool!
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Steven

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #36 on: January 14, 2023, 01:39:14 PM »
I put an automated version of the CryoSat-SMOS regional volume graphs here:

https://www.dropbox.com/s/aw6l61vpofmtcgv/cryosat-smos-regional-volume-7x2.png?raw=1

(click image to enlarge)



The graph will be updated twice per week, on Saturdays and Wednesdays.  Currently the latest available date is 9 January 2023 (which is actually the 7-day period from 6 to 12 January 2023).

oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #37 on: January 16, 2023, 02:44:30 PM »
THANKS. Bookmarked.

uniquorn

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #38 on: March 06, 2023, 10:27:04 PM »
A couple of animations to document possible thin Beaufort/CAB ice, particularly near 80N -150.
lol, the cs2smos ani was reversed
« Last Edit: March 07, 2023, 12:33:52 PM by uniquorn »

oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #39 on: March 07, 2023, 05:19:51 PM »
lol, the cs2smos ani was reversed
I was wondering how come there was no thickening and even some thinning, but didn't occur to me to ask. I just accepted it as is...

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #40 on: October 27, 2023, 10:24:37 PM »
The CryoSat-SMOS data have started updating again.  (As usual, the data for Autumn 2023 are preliminary and may be revised later.)

I have updated my graphics here:

https://sites.google.com/view/arctic-sea-ice/home/cryosat-regional
« Last Edit: October 27, 2023, 10:43:54 PM by Steven »

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #41 on: October 28, 2023, 09:13:53 AM »
Here are zoomed-in maps:

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #42 on: October 28, 2023, 03:18:25 PM »
And here is a tabular form of the data for this date (23 october, which is actually the 7-day average from 20 to 26 october).


oren

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #43 on: October 28, 2023, 08:24:28 PM »
Interesting. This year is much lower than expected from PIOMAS. I suspect CS-SMOS is the more accurate one these days.

Steven

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #44 on: October 29, 2023, 10:19:33 AM »
Indeed, only October 2011 and 2020 had lower volume on this date.

I'm not sure what to make of the relatively thin spots of CryoSat-SMOS north of Ellesmere and the CAA (see image below).  It doesn't seem to match with any low concentration areas this melt season.

On the other hand, the band of low concentration ice between Svalbard and the New Siberian Islands shows up very clearly on CryoSat-SMOS but only weakly on PIOMAS.  So I reckon CryoSat-SMOS does better in that area while PIOMAS may have too much ice on the Atlantic side.

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #45 on: October 29, 2023, 01:22:37 PM »
I'm not sure what to make of the relatively thin spots of CryoSat-SMOS north of Ellesmere and the CAA (see image below).  It doesn't seem to match with any low concentration areas this melt season.
Looking at the absolute thickness map, it appears the ice north of the western CAA is very thin, which actually makes sense. There was a lot of heat there during the melting season which must have removed a lot of thickness, and looking at AMSR2 animations from the end of Sep (e.g. https://forum.arctic-sea-ice.net/index.php/topic,4066.msg383159.html#msg383159) it appears the ice there had low concentration as well.
The ice north of Ellesmere has high absolute thickness, though low in relative terms. This may be due to movement north and freezing of thin ice instead; or due to movement south into the CAA Garlic Press that developed at the end of the melting season; or a measurement error. I would bet on the Garlic Press explanation but the animations aren't clear enough to show this.

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #46 on: October 29, 2023, 02:15:09 PM »
I'm not sure what to make of the relatively thin spots of CryoSat-SMOS north of Ellesmere and the CAA (see image below).  It doesn't seem to match with any low concentration areas this melt season.
The ice north of Ellesmere has high absolute thickness, though low in relative terms. This may be due to movement north and freezing of thin ice instead; or due to movement south into the CAA Garlic Press that developed at the end of the melting season; or a measurement error. I would bet on the Garlic Press explanation but the animations aren't clear enough to show this.

Maybe it's helpful to look back at the mid-April 2023 CryoSat-SMOS maps.  The anomaly map already had an area of relatively thin ice (compared to recent years) north of the CAA all the way to Western Ellesmere.  Given that the melt season probably had above-average melting in that area (and little or no drift, just a bit toward the Atlantic), it makes sense that it still shows as anomalously thin compared to recent years. 

The relatively thick ice in Bering, Chukchi, Western Beaufort, Kara and Barents in April has practically all been wiped out during the melt season.  Basically the only anomalously thick ice left now is in Laptev and Greenland Sea.

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #47 on: November 02, 2023, 09:28:37 PM »
I'm not sure what to make of the relatively thin spots of CryoSat-SMOS north of Ellesmere and the CAA (see image below).  It doesn't seem to match with any low concentration areas this melt season.
Looking at the absolute thickness map, it appears the ice north of the western CAA is very thin, which actually makes sense. There was a lot of heat there during the melting season which must have removed a lot of thickness, and looking at AMSR2 animations from the end of Sep (e.g. https://forum.arctic-sea-ice.net/index.php/topic,4066.msg383159.html#msg383159) it appears the ice there had low concentration as well.
The ice north of Ellesmere has high absolute thickness, though low in relative terms. This may be due to movement north and freezing of thin ice instead; or due to movement south into the CAA Garlic Press that developed at the end of the melting season; or a measurement error. I would bet on the Garlic Press explanation but the animations aren't clear enough to show this.


cs2smos shows the ice still thinning northwest of Ellesmere I. Maybe a combination of new leads and ongoing bottom melt on thicker ice. SIMB3-566570 lost 2cm two days ago further west near the Mclure strait.

cs2smos merged sea ice thickness with lead ice concentration overlaid at 60%
oct21-31
« Last Edit: November 02, 2023, 10:26:49 PM by uniquorn »

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #48 on: November 03, 2023, 10:43:16 AM »
I'm not sure what to make of the relatively thin spots of CryoSat-SMOS north of Ellesmere and the CAA (see image below).  It doesn't seem to match with any low concentration areas this melt season.
Looking at the absolute thickness map, it appears the ice north of the western CAA is very thin, which actually makes sense. There was a lot of heat there during the melting season which must have removed a lot of thickness, and looking at AMSR2 animations from the end of Sep (e.g. https://forum.arctic-sea-ice.net/index.php/topic,4066.msg383159.html#msg383159) it appears the ice there had low concentration as well.
The ice north of Ellesmere has high absolute thickness, though low in relative terms. This may be due to movement north and freezing of thin ice instead; or due to movement south into the CAA Garlic Press that developed at the end of the melting season; or a measurement error. I would bet on the Garlic Press explanation but the animations aren't clear enough to show this.


cs2smos shows the ice still thinning northwest of Ellesmere I. Maybe a combination of new leads and ongoing bottom melt on thicker ice. SIMB3-566570 lost 2cm two days ago further west near the Mclure strait.

cs2smos merged sea ice thickness with lead ice concentration overlaid at 60%
oct21-31

Thanks, uniquorn.

Meanwhile, I replaced my own cs2smos sea ice thickness map by an animation too.  At least the Siberian coastal ice is nicely thickening.

https://sites.google.com/view/arctic-sea-ice/home/cryosat-regional

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Re: CryoSat-SMOS Merged Sea Ice Thickness
« Reply #49 on: November 05, 2023, 06:22:45 PM »
Just noting that I started updating my CryoSat-SMOS Merged Sea Ice Thickness visualization for the 2023-2024 season at https://zacklabe.com/arctic-sea-ice-volumethickness/. I usually update it a few times per week.
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