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Messages - BornFromTheVoid

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1
Arctic sea ice / Re: The 2020/2021 freezing season
« on: Today at 05:50:25 PM »
Here's a side by side comparison of the first 25 days of ice growth this October compared to 2012
(Larger, better quality version on twitter here: https://twitter.com/Icy_Samuel/status/1320764047638302720)


2
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 06:20:54 PM »
Here's the sea ice forecast to the end of the month from the CMEMS NeXtSIM model. It appears to suggest a continuation of the very slow growth, mainly around the Laptev and Kara seas, with even a little loss around Chukchi.

Thomas Lavergne looked at another model which shows more significant growth overall, especially towards the ESS.
https://twitter.com/lavergnetho/status/1320340626127323136

3
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 24, 2020, 12:06:52 PM »
Here's the slow animation for the past week. Still areas of loss occurring, which surprised me a little.

4
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 23, 2020, 01:34:39 PM »
Can that be set for a narrower palette gamut (called squeeze at WorldView vs outlier clamp at CMEMS)? The bins are too large to resolve temperatures in the -2 to 0 and 0 to 2 ranges on the last frame of Nov 7th. The shoreline color seems off, not clear what temperature it is. Overall it does not seem that unreasonable: very little advance in the ice pack but with the stage still not set for rapid closure with so much open water between 0 to 2ºC.

It doesn't offer any other colour maps. It's easier to see in the full res in the link, but the discoloured shoreline is showing ice formation. Also, the dashed lines act as the 1ºC isotherms, providing slightly better resolution than the colour legend alone.
The website provides SSTAs at 0.5ºC intervals, which may help too. Not sure why they couldn't do that for the absolute SSTs...

5
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 23, 2020, 12:36:04 PM »

6
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 22, 2020, 05:32:43 PM »
Animation of the extent and distribution of ice for October 21st.
(Click to play)

7
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 21, 2020, 03:08:30 PM »
Records continue to tumble.
Now the slowest October increase to the 20th, lowest on record by 455k, largest -ve anomaly on record at 3.396 million km2 and almost 4 million km2 below the average of the 1980s

8
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 20, 2020, 07:06:46 PM »
Here's the chart showing the variations in the distance from ice edge/open water to the N. Pole for all the daily extent minima from 1979 to 2020 (measured every 5 degrees).
The trends largely resembles that of other measures:
2012 had the shortest average distance, at 944 km, followed by 2020 (991 km) and 2016 (1,060 km).
The 81-10 average is 1,328 km, and the maximum occurred in 1980 at 1,452 km.

There are some major limitations to this, especially looking at the minima for a single day when the ice edge may have reached closer to the N. Pole on days other than the minimum - but it's a start.

Anyway, I'll post some more regional data up tomorrow when I have more time.

9
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 19, 2020, 05:12:39 PM »
Zach Labe pointed out on twitter that the 5 day mean NSIDC extent has reached the largest negative anomaly on record (relative to 1981-2010).

I had a check, and this is true for the daily data too. In fact, each of the last 5 days have set a new record large -ve anomaly.

The previous record was 3.068 million km2, on October 8th 2012.
The last 5 days, October 14th to 18th, are:
-3.088
-3.128
-3.167
-3.209
-3.275




10
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 18, 2020, 12:58:16 PM »
Latest slow animation, 12th to 17th

11
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 17, 2020, 06:26:45 PM »
Thanks BFTV. It seems to me that the regions that were late to melt are early to freeze in both years. If true, this is probably due to the mixing that goes on when a region has been ice free for a longer period.

Cheers.
A useful comparison might the the date of ice loss (1st attachement) next to the October gain (2nd attachment). Judging by this, we should expect the Laptev sea to have the most difficult time freezing over.
This appears to be supported by the higher SST anomalies in the region currently.



12
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 17, 2020, 04:18:34 PM »
Here's an animation comparing the first 16 days of October with 2012
A slightly large file, ~7mb. Click to play.
(larger/better quality version is up on twitter: https://twitter.com/Icy_Samuel/status/1317469236709777416).

13
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 15, 2020, 01:59:43 PM »
The pressure gradients this weekend looks like producing some significant waves from the Chukchi through to the Laptev sea, often over 5 m. The effect this has on the halocline and newly formed ice should be interesting.
Data from the ECMWF


14
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 14, 2020, 10:57:40 AM »
Animation, 8th to 13th.

15
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 10, 2020, 03:42:04 PM »
I decided to measure the changes in the ice edge position, starting at the daily minimum.
For now, it's the ice edge position (first instance of open water) or where the ice is at its maximum extent (such as N of Greenland or along sections of the Arctic ocean coasts in some years) that's measured. Measurements are done every 5 degrees, but also grouped for stats on edges facing individual seas.

(Ideally, I could do something like this for every day of the year, all years, but that's gonna be some way down the road when my python skills have improved a lot!)

I've only done 79 to 89 so far, and the closest ice edge position, by far, was in 1979, at 678 km at 50 degrees east.
On average, the minimum with the closest ice edge position was 1984, averaging 1330 km.
I'll get it updated to 2020 during the week, hopefully, and do the maxima after that. For now, here's just a sample with 1979 to 1989.

Comments/suggestion welcome as always.

16
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 10, 2020, 01:03:26 PM »
Slow animation from the last 5 days.


17
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 08, 2020, 08:16:36 PM »
CMEMS sea ice forecast shows almost no growth over the next week. Should it come off, record lows, and by huge margins, should be expected soon.

Below is a comparison between 2012 and 2020, with AMSR2 data to the 7th for 2020, and CMEMS for 8th to 14th.

18
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 07, 2020, 06:20:03 PM »
Some great new forecast data made free by the ECMWF.
Includes sea ice, snow, waves, cloud and all the usual meteorological stuff.
A few sample below.
https://apps.ecmwf.int/webapps/opencharts/


19
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 07, 2020, 03:02:15 PM »
The current forecast is for quite a strong dipole to continue, with winds compressing the sea ice along the Chukchi and Russian facing edges, and spreading it out towards the Atlantic (animation below).
This shows up very nicely in the CMEMS sea ice forecasts to the 13th (2nd attachment) which predicts, amazingly, further significant losses along the Chukchi, ESS and (to a lesser extent) the Laptev ice edge. Gains in the other regions barely enough to produce growth overall.

I'd expect area and extent to be below 2012 next week, with truly exceptional regional record low ice values and further record smashing air temperatures as a result.

20
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 06, 2020, 02:32:34 PM »
Images and animation for today.

Btw, I'm going to start making these updates roughly twice per week after this

21
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 05, 2020, 01:52:13 PM »
Today's images and animation

22
Arctic sea ice / Re: Latest PIOMAS update (Oktober)
« on: October 05, 2020, 01:49:55 PM »
Two images. Big thanks to Wipneus for the data provided.


23
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 04, 2020, 10:35:23 PM »
The same as above, but split based on the dates mentioned by Oren.
So we've 1979-1992, 1993-2006 and 2007-2020.
And a final one with all of the years.

I'll work on actually doing some actual analysis of these later in the week when I've some more time.

EDIT: Just spotted a mistake in the final image... just a sec Fixed! Though the images may be in the wrong order now. Oh well.

24
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 04, 2020, 10:32:52 PM »
Here are the sea ice minimum extent persistence, based on the single day minimum values.
They are split, roughly, by decade.

25
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 04, 2020, 12:47:33 PM »
Images and animation for today

26
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 04, 2020, 02:02:41 AM »
Nice suggestions VAC. I'll try to get my hands on those maps.

Been up late dealing with reddit moderating drama, and playing about with some suggestions made previously.

As a start, here's the ice persistence map, and another highlighting the last year ice was present, for just the single day minima from 1979 to 1989.

I'll continue to adjust the colours, add more months/years/decades and try out other suggestions in the coming days too.

27
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 03, 2020, 11:58:35 AM »
Good suggestions Oren. I'll work on some of those during the coming week as I get the time.

Here's today images and animation. A flash filling in of the Chukchi bite, curious to see if it persists.

28
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 02, 2020, 10:25:35 PM »
Cheers for all the suggestions so far, lots of good stuff! I'll post a few more versions tomorrow for critiquing.

I am also working on a map that highlights the year that sea ice last covered a particular area.

Overall, I like the idea of generating a static image that kind of highlights directional and temporal melt momentum - like what parts of the Arctic are retreating towards the N. Pole the fastest, and how has this varied over time. Easy to do via animations, but a bit more tricky for static images.

29
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 02, 2020, 07:18:06 PM »
Playing around with some more data viz stuff.
So below is the September sea ice extent persistence. Basically, it's like stacking the average September sea ice extent for every year from 1979 to 2020 on top of each other.
Where sea ice is present in every year, the pixel value is 42 (white in the image).
Where it's present in 20 of the years, it gets a pixel values of 20 (light green)
Where it was only present in one year, it gets a value of 1 (dark orange)
And everything in between!

I'm open to suggestions on how best to display this data. I plan on doing the same for all other months too

30
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 02, 2020, 12:57:06 PM »
Todays update

31
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 01, 2020, 02:34:45 PM »
Looks like most of the increase in the NSIDC extent is false ice towards the south east of Greenland, near Iceland.

32
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 01, 2020, 12:37:46 PM »
Here's the sea ice concentration animation for all of September. The dynamical movements are pretty interesting to watch.
There'll be a larger, better quality version going up on my twitter page in about 2.5 hours

(Large animation, ~11mb. Click to Play)

33
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 01, 2020, 11:34:14 AM »
The slow changes continue, and the Chukchi bite keeps growing

34
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 30, 2020, 11:53:39 AM »
Images and animation for today.

35
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 29, 2020, 01:42:21 PM »
And the latest images and animation.

BFTV, the last frame in the final figure (the gif), shows the total change over the period- that is itself a nice visualisation and could be a stand-alone

Here ya go

36
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 29, 2020, 10:56:55 AM »
And the latest images and animation.

37
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 29, 2020, 10:53:02 AM »
Oren is correct, my chart was wrong. Need to check the rows the calculations are being performed on! The previous chart was the difference in the max to min from year to year, not the min to min.

Here's the actual minimum to minimum difference version (fingers crossed!)

38
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 28, 2020, 10:34:47 AM »
Today's images and animation.
Some big losses around the Chukchi region the last 2 days with southerlies dominating here. This looks likely to continue for the coming week, so definitely an area worth watching.

39
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 27, 2020, 12:01:10 PM »
  BTV - Could do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.

I think this is what you're after.

40
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 27, 2020, 11:59:28 AM »
Todays images and animation



41
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 26, 2020, 05:27:20 PM »
Trend in the maximum extent minus the minimum extent.
Inset map of the 2020 max and min extent too.

42
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 26, 2020, 01:17:11 PM »
September 21-25.

2019.

WOW

The Atlantic Front pushes beyond 85 N again. Amazing

Closest point is 503 km from the N. Pole

43
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 26, 2020, 12:42:13 PM »
Todays images an animation

44
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 25, 2020, 11:20:16 AM »
Today's images and animation

45
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 24, 2020, 10:41:37 AM »
Today's images and animation, with the transformation of the Beaufort tail into the Beaufort loop, once again.
(As always, a larger version of the animation on my twitter: https://twitter.com/Icy_Samuel/status/1309048320669691905)

46
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 23, 2020, 04:50:50 PM »
10 days of refreezing (Sep 13th to 22nd). Nearly 6mb, click to play

47
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 23, 2020, 10:13:07 AM »
Today's images and animation. Beaufort Sea still hasn't figured out what it's doing.

48
Arctic sea ice / Re: The 2020 melting season
« on: September 22, 2020, 04:17:11 PM »
NSIDC indulging in bad science?

And in that report for some unknown reason NSIDC decided to split the 42 years into 3 lots of 14 years.

It's not really an unknown reason though. The main point was highlighting how anomalous the minima have been since 2007 (14 years from then to 2020), which they have been. We haven't seen any minimum since 2007 equal or be above any minima pre-2007.

However, I agree that looking at the individual linear trends in those periods was pointless, for the reasons you highlight. If they had left them out and just focused on how low the post-2007 minima have been, it would have totally ok. But adding in the linear trends just seems arbitrary and open to misinterpretation.

It just comes across as a little rushed without considering the optics.

49
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 22, 2020, 11:57:26 AM »
Today's images and animation

50
Arctic sea ice / Re: The 2020 melting season
« on: September 21, 2020, 03:23:31 PM »
As it's the end of the melt season, here's all the extent projections from March 1st to last week, using daily data from the last 20 years.
A pretty big file size, click to play.

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