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Glen Koehler

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Re: Fram Export
« Reply #50 on: June 11, 2019, 04:28:26 PM »
Thanks Oren, exactly what I was looking for.  I had seen that before just couldn't remember where.
johnm33 - ice only.  Just trying see how much export is contributing to "melt" season relative to other years.
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Pragma

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Re: Fram Export
« Reply #51 on: June 12, 2019, 01:11:20 AM »
Here is a link to the latest graph.

https://forum.arctic-sea-ice.net/index.php/topic,119.msg203472.html#msg203472

Thanks, but I would like to see something that integrates the flow over a week or month. I found a number of sites that only list export for the winter months and was shocked to find that the winter export is on par, or a little larger than the melt season. Unfortunately what I found only went to 2010.

Any other suggestions most welcome.

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Re: Fram Export
« Reply #52 on: June 12, 2019, 01:32:47 AM »
But that’s normal. Export weakens during (most of the) summers with a few exceptions. There is a graph from a paper in this thread that illustrates this well.

https://forum.arctic-sea-ice.net/index.php/topic,298.msg113817.html#msg113817
« Last Edit: June 12, 2019, 01:37:59 AM by Sterks »

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Re: Fram Export
« Reply #53 on: April 23, 2020, 01:12:28 PM »
Its still there.

sedziobs

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Re: Fram Export
« Reply #54 on: July 15, 2020, 05:38:52 PM »
Uniquorn posted a wonderful ASCAT animation of the 2019/2020 freezing season. Below is my attempt to delineate areas of export since the September 2019 minimum by tracking features.

Red exits the Fram, blue into the Barents Sea, yellow into Nares Strait, and green into McClure Strait. It wasn't a very active season for Nares or the garlic press.

For me the takeaway is that melt in the Pacific and American sectors is much more consequential for multi-year ice than how far the ice edge retreats on the Atlantic or Laptev fronts.

FishOutofWater

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Re: Fram Export
« Reply #55 on: July 15, 2020, 09:03:26 PM »
You are quite correct that the Beaufort gyre was once the place that thick multiyear ice went round and round, with a modest fraction lost via export through the Fram and Nares straits. The accumulation of heat in the Beaufort and Chukchi seas turned that region into an ice killing zone, melting most of the multiyear ice in the Arctic ocean.

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Re: Fram Export
« Reply #56 on: July 16, 2020, 04:28:27 AM »
Proximity to Greenland and northern CAA seems to be most important for long term ice survival. To a lesser degree proximity to the the north pole helps as well. In recent years and especially this year melt has increased along that coast. Originally four year or older ice was considered multiyear ice.


Now I don't think there is enough ice that old to really talk about multiyear ice.


 Peak ice extent for 4 year old ice last year was in Oct at 132,000 km^2 (1.5% of total ice extent) with an average over the last 20 years of about 2.4 million.
Minimum ice in Sep was 53,000 km^2 (1.3% of total ice extent) with a 20 year average of about 2.4 million.   

sedziobs

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Re: Fram Export
« Reply #57 on: July 16, 2020, 08:09:55 PM »
Right, significant 4+ yr old MYI is a thing of the past. I was more referring to claims of one melting season "setting up" the next one. Extensive melt at the pole, a deep Laptev bite, or an advancing Atlantic front will have limited effects on future seasons compared to events on the Pacific and American sides.

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Re: Fram Export
« Reply #58 on: August 05, 2020, 02:05:51 AM »
This buoy data is old I wish they had an update. I found it poking around in the Hycom website. I also wish I had the same for Bering strait. This is sea water export at 1320 meters below the surface not ice on the surface.

Steven

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Re: Fram Export
« Reply #59 on: January 08, 2023, 09:10:20 PM »
On the OSISAF website there is a Low Resolution Sea Ice Drift product (OSI-405).

I downloaded the numeric data from their ftp and used it to calculate sea ice extent export across Fram Strait, using the red boundary line in the image below:



They have data from Oct 2015 to 6 Jan 2023 (near real-time).  There are no data for May-Sep 2016 and May 2017.

Here is a plot of the calculated cumulative export for each year:



This suggests 2022 had relatively strong Fram export.  This is in contrast to the Fram volume export calculated from the PIOMAS model, which was relatively low in 2022.

Calculated data attached.

gerontocrat

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Re: Fram Export
« Reply #60 on: January 08, 2023, 09:38:06 PM »
On the OSISAF website there is a Low Resolution Sea Ice Drift product (OSI-405).

This suggests 2022 had relatively strong Fram export.  This is in contrast to the Fram volume export calculated from the PIOMAS model, which was relatively low in 2022.
The OSAF data is in Km2.
The PIOMAS data is in Km3.

Is the data difference in 2022 due to lower average ice thickness of exported ice (or are the 2 datasets irreconcilable)?

If (a big if) I have time I will calculate the average thickness for the years that are available.
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Steven

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Re: Fram Export
« Reply #61 on: January 08, 2023, 10:53:12 PM »
The OSAF data is in Km2.
The PIOMAS data is in Km3.

Is the data difference in 2022 due to lower average ice thickness of exported ice (or are the 2 datasets irreconcilable)?

It may also be related to the location of the Fram boundary line.  Some years had little sea ice reaching the line, as the ice already melted north of Svalbard or drifted into Barents instead of Fram. 

Maybe I should redo the calculation using a modified line between North Greenland and Franz Josef Land (similar to the recent discussions in the PIOMAS thread), but that will have to wait until tomorrow or later.  Maybe something like the yellow line in the image below.

oren

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Re: Fram Export
« Reply #62 on: January 08, 2023, 11:33:55 PM »
Amazing.
My personal frustration is that I lack the time to sit and drill down and play around and make charts with this wonderful multitude of data that Steven has been providing recently. And as time goes by my time availability situation seems to be getting worse and worse.

gerontocrat

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Re: Fram Export
« Reply #63 on: January 08, 2023, 11:55:28 PM »
Hullo Sreven,

While you were working on it so was I.

Year       Average
            Thickness   Comments
2015        3.54     OSAF data missing from Day 91, PIOMAS sum used is to day 90
2016        1.82   OSAF Data missing from day 212, PIOMAS sum used is to day 211
2017        1.78   OSAF Data missing from Day 341, , PIOMAS sum used is to day 340
2018        1.80   Many zero entries
2019        1.87   Some zero entries
2020        2.47   
2021        3.08   
2022        1.78

I also did a graph of daily thickness from 2015 to 2022.
Basically it is junk.

Maybe using 7 day trailing, or 14 day or one month averages a cleaner result would follow. But is it worth it?

I am inclined to trust the PIOMAS data more than the OSAF with all its gaps and zero values (the zero values I made blank in the thickness graph data).
   
I am not sure if this is worth pursuing for a year or two at least.
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gerontocrat

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Re: Fram Export
« Reply #64 on: January 09, 2023, 02:29:02 AM »
Hullo Steven

A closer look at the OSAF data
I made a cumulative graph from the OSAF data. It should look the same as yours. 2016 and 2017 it isn't. Data stops at day 212 in 2016, and day 340 in 2017.

I also find it hard to believe zero export or import (zero entries) in 2017 from day 182 to day 235 and a similarly long period of zeroes in 2018.

I attach the two graphs. Have I managed to screw up the data?
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oren

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Re: Fram Export
« Reply #65 on: January 09, 2023, 07:33:34 AM »
Gero, looking at the CSV perhaps your data processing bunched together the days with data?
In the CSV 2016 has data from day 1 to 122, and then from 276 to 365.
I don't know the reason for the gap, but it is different from the data ending on day 212.

gerontocrat

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Re: Fram Export
« Reply #66 on: January 09, 2023, 09:56:27 AM »
Gero, looking at the CSV perhaps your data processing bunched together the days with data?
Good morning, Oren.

I thought of that this morning, and yes, it looks like the standard utility in LibreOffice for opening a csv as an unformated text file does exactly what you say. Damnation.

I attach the corrected graph from the corrected data which agrees with Steven's graph, but the daily thickness graph is still junk.

I apologise on behalf of LibreOffice for the mix-up.

I am not sure if my analysis is going anywhere, so I leave it for other things.

Gero
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Steven

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Re: Fram Export
« Reply #67 on: January 09, 2023, 07:08:04 PM »
I also find it hard to believe zero export or import (zero entries) in 2017 from day 182 to day 235 and a similarly long period of zeroes in 2018.

Zero values can happen in summer and autumn when there is little or no ice in Fram Strait, or just a bit of low concentration ice for which OSISAF has no sea ice drift vectors.

As for the missing data, those are in May-Sep 2016 and May 2017 as mentioned before.

Note that OSISAF has a visualization tool here  (select the product "LR-Drift"), which can be used to browse through the years and days.

Steven

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Re: Fram Export
« Reply #68 on: January 09, 2023, 07:30:15 PM »
Meanwhile I ran the OSISAF numbers for some variants of Fram strait.  See the red, orange and yellow lines in the image below:



The red line is the one that was used upthread yesterday.

Here is the export across the orange line:



And here is the export across the yellow line (to Franz Josef Land):



(2016 is biased low in these graphs due to missing data.)

Each of these graphs shows strong export in 2022.

gerontocrat

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Re: Fram Export
« Reply #69 on: January 09, 2023, 07:38:34 PM »
OK Steven,  I will run the KM2 data from the new line against the PIOMAS Fram+FJL KM3 data & & see what we get.

I think on the KM3 dataset I have to get rid of -ve values, i.e. reverse flow as the KM2 data seems to have these as zero? But I will check first.

Gero
« Last Edit: January 09, 2023, 08:48:37 PM by gerontocrat »
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gerontocrat

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Re: Fram Export
« Reply #70 on: January 09, 2023, 09:42:06 PM »
Quote
author=Steven link=topic=298.msg355999#msg355999 date=1673289015
And here is the export across the yellow line (to Franz Josef Land):

Each of these graphs shows strong export in 2022.
Hullo Steven,

Any chance of you downloading the yellow line data as a csv file. (I've found a different way to copy it into my LibreOffice file without any screw ups)

Gero
« Last Edit: January 09, 2023, 09:58:12 PM by gerontocrat »
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A-Team

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Re: Fram Export
« Reply #71 on: January 10, 2023, 12:16:34 AM »
Great effort ... three recommendations:
  • use the blue Fram gate to allow comparison with the scientific literature.
  • chase down the re-gridding procedure of OsiSaf which you already can see provides inadequate density for scattered spinning floes of the Fram.
  • look up the irregular and sparse gridding of Piomas in this area and ask if an Arctic Ocean thermodynamic model could possibly apply given the surface currents, counter-currents and eddies.

In terms of vetting or calibrating, there's long been a cross-channel array of underwater moorings with upward looking sonar that can accurately measure ice thickness by echo delay. The data can only be read out once a year by ship visit.

If I recall the moorings are a bit south of all the proposed gateways and a bit north of the deepest part of the Arctic Ocean, the Molloy Deep at 5550 m (18209 ft) below sea level.

https://www.livescience.com/explorer-dives-deepest-part-arctic-ocean.html
« Last Edit: January 10, 2023, 12:28:03 AM by A-Team »

Steven

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Re: Fram Export
« Reply #72 on: January 14, 2023, 12:56:38 PM »
I think on the KM3 dataset I have to get rid of -ve values, i.e. reverse flow as the KM2 data seems to have these as zero? But I will check first.

There are some negative daily values for OSISAF Fram export too.  But generally, negative values occur less frequently for OSISAF than for PIOMAS.  Anyway, I don't think it's useful to calculate "thickness" by combining those totally different datasets.


chase down the re-gridding procedure of OsiSaf which you already can see provides inadequate density for scattered spinning floes of the Fram.

I looked around on the OSISAF website.  Besides the low-resolution product, they have a medium-resolution sea ice drift product, but apparently the latter has lots of data gaps and no data at all for Fram.  The technical details of their algorithms are here and here.  It seems they use a motion tracking algorithm using pattern matching on brightness temperature satellite images.  Could be interesting to see how it works, and if it can be improved to get higher resolution for Fram, but I assume that's far from easy, and I don't have enough time to dive into the details of this.

Steven

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Re: Fram Export
« Reply #73 on: January 14, 2023, 01:24:31 PM »
Interesting paper published this week:

Yang et al (2023, open access),

The evolution of the Fram Strait sea ice volume export decomposed by age: estimating with parameter-optimized sea ice-ocean model outputs

https://iopscience.iop.org/article/10.1088/1748-9326/acaf3b

Quote
Abstract

Sea ice export through the Fram Strait is crucial in the dynamic evolution of Arctic sea ice and can further modulate Arctic sea ice mass balance as well as the ocean thermohaline circulation.  In this study, based on outputs from a parameter-optimized and fully physical ocean–sea ice coupled model and sea ice age observation, we estimate sea ice volume (SIV) flux and its age evolution via the Fram Strait.  The estimate of mean annual SIV flux is about 1605 ± 315 km3 yr−1 without a significant trend for 1979–2021.  Combining with sea ice age data, the variation of the sea ice age and its corresponding SIV flux are obtained for 1984–2020.  The SIV flux of 1st-year ice significantly increases as expected, but it still contributes very little to the total flux in the 2010s with a proportion of 3.5%.  SIV fluxes of different ages in multi-year ice present diverse variations.  The proportions of 2nd-year ice and 3rd-year ice in the annual SIV flux show an extreme increase from 6.8% and 25.0% in the 1980s to 49.0% and 38.8% in the 2010s, respectively, while the proportions of 4th-year ice and 5th-year and older (5+ year) ice significantly decrease from 22.8% and 45.0% in the 1980s to 7.1% and 1.6% in the 2010s, respectively.  Meanwhile, the prevailing age of annual volume export via Fram Strait shifts from 4th-year and 5+ year ice to 2nd-year and 3rd-year ice around 2007/2008.  It is worth noticing that the variation in Fram Strait ice export modulates the variation in Arctic SIV prior to 2008, but the reverse is true after 2008, indicating a decreasing influence of Fram Strait SIV export on Artic SIV variability with decreasing sea ice age.  The results are beneficial to promote the understanding of the evolution of Fram Strait SIV export under the warming Arctic.




gerontocrat

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Re: Fram Export
« Reply #74 on: January 21, 2023, 03:51:22 PM »
The above post shows that as the years progress the amount of MYI (i.e. volume) exported declines,  while there  is little change to the area of sea ice exported.

A good confirmation of Steven's PIOMAS Fram export data that shows a decline in Fram Export ice volume over time.

Meanwhile, here are the Ice Export Volume graphs for the first 15 days of Jan 2023.

The first 2 graphs are ice export down the Fram Strait.

The 3rd and 4th graphs are ice movement to/from the Barents and the Central Arctic region across the sea between Svalbard and FJL.(1)
They show that so ice movemnt has mostly been from the Brents to the Central Arctic, i.e. ice imort, not export. There is supposed to be some wild weather coming up from the North Atlantic into the Atlantic Front over the next week or so. Some big changes on the way?

click images to enlarge

(1) Ice movement to/from the Barents
These graphs are the subtraction of Steven's data for all Ice volume export across a line drawn from NE Greenland  to FJL minus Fram Export across the line from NE Greenland to Svalbard. This surely gives a good estimate of ice movement to/from the Barents.
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A-Team

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Re: Fram Export
« Reply #75 on: January 21, 2023, 04:34:59 PM »
Please explain: none of this seems consistent with what we have been seeing since July with multiple buoys. They provide long-term, hourly, high accuracy GPS location involving no recognition algorithms, satellite interpretation, re-gridding, thermodynamic models or ice trend fitting.

Buoys are by far the most reliable source of export information. In recent years, they have been out there in working condition at adequate density to furnish accurate ice movement trajectories (along with actual ice thicknesses and underlying water properties).

If the best quality data (buoy trajectories) is not factored in, there is something really wrong with the publication.

What is new with buoys is that Uniquorn here has been greatly outperforming the academic buoy community in terms of far better, more comprehensive displays and the ensuing critical products.

I am yet to see a single published journal article that makes appropriate scientific use of Arctic buoy data. It is the same with the Beaufort "Gyre" vs the undeniable Ascat/AMSR2 reality --  the software skills to make the necessary animations are just not part of the culture. The journals just want stills for their pdfs.

In the ten years I've been on the forum, we have only seen a single academic making research-grade Arctic time series. (I am very familiar with what scientific research consists of, my papers have been cited over ten thousand times.)

In my view, the ice/climate talent is definitely out there but mainly focused on Antarctic ice and Greenland glaciers. The Arctic Ocean lacks accessible fixed observation platforms (aka land) and is very expensive -- and sometimes futile -- to study by ship (Polarstern year).

Realistically, what can be expected when the affected Nordic countries + n Canada barely add up to the population of California (454 universities): ongoing DMI 80ºN, AI4EO, Bjørn Lomborg fiascoes.
« Last Edit: January 21, 2023, 05:50:11 PM by A-Team »

Glen Koehler

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Re: Fram Export
« Reply #76 on: January 22, 2023, 07:08:51 PM »
    I doubt that aversion to animation by journal editors is the problem, and from my layman's armchair view there appear to be many highly trained folks and good science being done on ASI questions, MOSAIC being just one example.  A specific list of the questions you would like to see addressed might be useful.  Your post already defines some, but a list would make it even clearer.
« Last Edit: January 24, 2023, 02:29:51 AM by Glen Koehler »
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oren

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Re: Fram Export
« Reply #77 on: January 23, 2023, 12:13:22 AM »
There is lots of good science done on ASIF but I believe A-Team was referring to official academic science, which lags a lot of what is done here in terms of animations and use of up to date near real time data sources.

Andy Hultgren

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Re: Fram Export
« Reply #78 on: January 23, 2023, 03:30:07 AM »
On the freezing season thread, Glen highlighted this passage from Yang et al 2023 (posted by Steven above):

Quote
It is worth noticing that the variation in Fram Strait ice export modulates the variation in Arctic SIV prior to 2008, but the reverse is true after 2008, indicating a decreasing influence of Fram Strait SIV export on Artic SIV variability with decreasing sea ice age.

I just took a quick look at the paper. Their conclusion is based on Figure 4, attached, which (respectfully) I think I might interpret differently than they do.

In the figure, you can see that for "Arctic SIV lags", when Fram export is high, arctic SIV is low ~8 months later. That is true in both the pre-2008 and post-2008 samples. It is less strong in the post-2008 sample, but 1) there are fewer years post-2008 than pre-2008 (think statistical power), and 2) 2015 may be anomalous -- see Gerontocrat's recently posted charts.  It is this portion of the figure on which Yang et al base their sentence in the abstract that I quoted above. I doubt they are powered to statistically distinguish pre-2008 vs. post-2008 correlations here, and regardless it remains the case in both periods that high Fram export correlates with low arctic SIV about 8 months later.

In that same Figure 4, the "Arctic SIV leads" exhibit a much stronger relationship with Fram export in the post-2008 period. If volume is high in the Arctic, Fram export anytime from 1-16 months later is persistently high, in the post-2008 period. This is not true in the pre-2008 period. (Aside: we should wonder how sensitive that post-2008 result is to dropping any one year of data.) But, I'm guessing what this actually means is that up to 2007, there was always plenty of ASI available to be exported out the Fram, so variation in (leads of) SIV had little effect on Fram export. After the 2007 melt season, Fram export was limited (at least for part of the year) by whether there was ASI available to export. Which induces the post-2008 positive correlation between SIV leads and Fram export observed by the authors.

tl;dr: Based on their own figure, I would push back on that statement in Yang et al's abstract.

Alexander555

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Re: Fram Export
« Reply #79 on: January 30, 2023, 10:15:37 AM »
Did it look the same in the years before 2015 ? Most export in the months there is plenty ice. Ofcourse if there is plenty, plenty can be exported. But i would think the ice was more solid in the years before. Did that slow down the export ?

gerontocrat

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Re: Fram Export
« Reply #80 on: January 30, 2023, 08:45:31 PM »
Did it look the same in the years before 2015 ? Most export in the months there is plenty ice. Ofcourse if there is plenty, plenty can be exported. But i would think the ice was more solid in the years before. Did that slow down the export ?
OSAF data only goes back to 2015, but PIOMAS data goes back to 1979.

Here are 4 graphs...
Sea ice Area export from PIOMAS data, - 2 graphs
Sea ice Volume export from PIOMAS data - 2 graphs.

Ice Area export is remarkably stable, while Ice Volume export is in decline, reflecting thinning of the ice pack over the years.

click images to enlarge
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jdallen

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Re: Fram Export
« Reply #81 on: January 31, 2023, 06:39:16 AM »
Possibly tangential…. Over all, similarly to A-Team having followed this forum for 10 years, my sense, like his, is that most of the academics are behind the curve compared to the constant daily analysis and discussion being done here.

There are a few exceptions, but I think that’s generally the case, and in fact, observations made *in* these forums has been picked up and run with by researchers whom, once having been introduced to an idea, have picked up and run with it.

Now, generally I have no problem with this; it is in fact exactly the sort of thing we want to have happen.  (Just cite people who’ve done stuff here when you use it please, OK?! It won’t detract from what you do, really!)

But, back to the Fram…

There seems a pretty direct relationship between volume and transport, particularly looking at transport as a trailing factor to volume.

It has practical immediate implications, especially at this stage in the refreeze, as what’s happening is “setting the table” for what happens after the impending max.  The more (sadly, depressingly rare) MYI that gets kicked out the door, the more likely it is the remaining fraction will be too thin and too weak to avoid getting everlastingly scorched in June July and August.

I’ll get off my soap box now…
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Re: Fram Export
« Reply #82 on: January 31, 2023, 12:31:57 PM »
OSAF data only goes back to 2015, but PIOMAS data goes back to 1979.

Ice Area export is remarkably stable, while Ice Volume export is in decline, reflecting thinning of the ice pack over the years.

Looking at these graphs, two things come to mind: The remarkably steady area export implies a mechanical limit or threshold in area that can be exported. In other words, area export would be much bigger if it wasn't bouncing against some sort of upper limit.

Volume export is also remarkably steady - it doesn't fall with the total volume decline. Which inidicates (along with the stable area export) that the ice being exported is of a very uniform thickness, and hence of a very uniform age and originating from an area where ice production has stayed very similar for the entire period.

The loss in Arctic volume would then have to have happened outside of the "sourcing" area of Fram export - for example, with loss of old ice piled up in the periphery along the coast, or with loss of ice in areas outside the Fram export sourcing area.

And the final conclusion has to be that so far, Fram export has had no impact on the Arctic Sea Ice balance, or in other words, winter export will not effect summer melt.
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jdallen

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Re: Fram Export
« Reply #83 on: February 01, 2023, 02:05:56 AM »
<snippage>
And the final conclusion has to be that so far, Fram export has had no impact on the Arctic Sea Ice balance, or in other words, winter export will not effect summer melt.

/agree.  The volume certainly won't, the area/extent actually may be more relevant, as it affects albedo, but even then it will be far less an impact than weather and heat broadly distributed across the entire region.

I think it's primary effect now is indirect - which is generally mechanically destabilizing the pack as a whole.  However, that's been going on for nearly a decade.
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gerontocrat

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Re: Fram Export
« Reply #84 on: February 12, 2023, 01:06:26 AM »
Fram Export January 2023
After a slow start strong export, by Jan 31 cumulative ice export above the 1980's average.

January also saw an increase in the Greenland Sea sea ice area

graphs attached, click to enlarge
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Steven

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Re: Fram Export
« Reply #85 on: February 12, 2023, 08:15:18 PM »
three recommendations:

use the blue Fram gate to allow comparison with the scientific literature.



The graph below shows the export across the blue line in the above image.  Actually I used the grid points on the north side of the blue line, because OSISAF has better data coverage there (giving 8 grid points instead of 5).

Graph starting in October instead of January this time, as the dataset starts in Oct 2015, with data up to 10 Feb 2023. 

(The dashed horizontal lines in May-Sep 2016 and May 2017 indicate missing data.)


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Re: Fram Export
« Reply #86 on: February 13, 2023, 09:42:03 PM »
I dug up the instructions for ascat 'interferometry'. Thought it might be a useful visualisation for fram export. Especially over the last few days.
The method requires 3 days data, so sep27-feb9
mp4 better than gif in this case due to the number of colours
« Last Edit: February 13, 2023, 10:31:45 PM by uniquorn »

oren

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Re: Fram Export
« Reply #87 on: February 13, 2023, 11:35:42 PM »
Very interesting animation. Thanks for making the effort, seems difficult to do.
Do you know if SIC-Leads uses Ascat as its movement data source?

uniquorn

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Re: Fram Export
« Reply #88 on: February 14, 2023, 12:41:33 AM »
No, but I doubt it. The leads in Sic-Leads are more similar to brightness temperature and ascat doesn't show leads very well, only movement of similar ice surface types. Note that those surface features often change over time too. Not only the big whitewash during summer.

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Re: Fram Export
« Reply #89 on: February 15, 2023, 09:44:11 PM »
Ascat fram export comparison, jan1-feb14, 2010-2023. 38MB
missing frames have been duplicated

A-Team

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Re: Fram Export
« Reply #90 on: February 16, 2023, 06:51:06 PM »
Quote
ascat jan1-feb14, 2010-2023. 38MB
Wow, thanks. Very nice resource. People can save out as a smaller mpg from ImageJ , slice it out into the individual 14 years, or do one-stop enhancements.

The three-frame animation below averages all 45 days for each year, then enhances contrast, then index-colors with ICA2. Interpretation left to Oren.

gerontocrat

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Re: Fram Export
« Reply #91 on: February 22, 2023, 04:56:55 PM »
PIOMAS FRAM Export data updated by Steven to 15th February

I attach graphs of Fram ice export volume and area graphs. In early February there was a drop in daily export but overall Fram ice export this year to date is high.
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gerontocrat

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Re: Fram Export
« Reply #92 on: February 22, 2023, 05:03:57 PM »
PIOMAS FRAM Export data updated by Steven to 15th February

I also attach graphs of ice export via the Fram Strait + the passage from the Barents positioned from Svalbard to FJL.

From this can be calculated ice flows from and to the Barents seas to the Central Arctic, which so far accululate to less than zero. Graphs attached
« Last Edit: February 22, 2023, 05:14:18 PM by gerontocrat »
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gerontocrat

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Re: Fram Export
« Reply #93 on: February 22, 2023, 07:52:11 PM »
And another graph showing a different way of presenting the gradual decline in ice thickness exported via the Fram.

Note the wobbles in the early days of the year - low data values always liable to produce odd results.
« Last Edit: February 22, 2023, 07:57:40 PM by gerontocrat »
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gerontocrat

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Re: Fram Export
« Reply #94 on: March 05, 2023, 07:59:48 PM »
Fram Ice Export to Feb 28th

In February daily FRAM ice export was mostly well above average, with the cumulative export ending the month nearly twice the 2010's average.

However, in the Barents, daily ice flows to and from the Central Arctic between Svalbard and FJL were a mixture of flows to and from the Barents, with the net cunmulative flows ending the month at zero.

ps:Steven: please please please update the Fram export area data? It would let me do the thickness calcs. (once a month would be fine by me)

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Steven

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Re: Fram Export
« Reply #95 on: March 05, 2023, 11:45:10 PM »
ps:Steven: please please please update the Fram export area data? It would let me do the thickness calcs. (once a month would be fine by me)

It's not available: the gridded sea ice concentration file on the PIOMAS website has not been updated since mid-February.  I guess they forgot to update that file this time, and it will probably be updated in a few weeks.

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Re: Fram Export
« Reply #96 on: March 12, 2023, 05:27:25 PM »
Fram export has been very strong in the last 3 months according to the OSISAF data.

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


Attached is an animation of the OSISAF sea ice drift maps for the last 3 months, and an average drift map for this freezing season so far.  (The arrows show the direction and relative magnitude of the drift, not the absolute magnitude.)
« Last Edit: March 12, 2023, 05:50:32 PM by Steven »

be cause

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Re: Fram Export
« Reply #97 on: March 13, 2023, 08:50:08 PM »
export via Fram etc looks like being a very significant factor this year . Already we have sailed past the 2017/8 season with over 6 months to spare and are over 100,000 sq km ahead of all recent years at present .
   Export volume has fallen recently even as area has increased owing to more young ice in the mix . This will soon change if current forecasts are realized  and more multi-year and multi-meter ice are lost from the basin .
   I suggested elsewhere that we could pass 1 million sq km before the summer . Current trajectory has it being reached mid April !
   With Nares playing an important supporting role in exporting the thickest multi-year ice as well , I am wondering what ice will be left in September if many other weather events line up .
   And we start the melting season 750k sq km less ice than 2012 .
« Last Edit: March 13, 2023, 09:07:36 PM by be cause »
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Re: Fram Export
« Reply #98 on: March 15, 2023, 07:45:01 PM »
This is significant new research on Fram export.

https://www.yahoo.com/news/arctic-sea-ice-thins-2-160510490.html

Renerpho

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Re: Fram Export
« Reply #99 on: March 15, 2023, 10:42:58 PM »
This is significant new research on Fram export.

https://www.yahoo.com/news/arctic-sea-ice-thins-2-160510490.html
Interesting, thanks! Of all things affecting the ice, I would not have thought aerodynamics played such a key role.
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.