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Messages - Stephan

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1
Antarctica / Re: PIG has calved
« on: Today at 09:51:58 PM »
I watch Thwaites and PIG carefully on EOSDIS worldview.
Please look at the big gap of open water that has appeared behind the 2017 PIIS calving remains. Unfortunately the "calving crack" of Oct 2018 is shaded by thin clouds. But it must have widened massively yesterday and today. I will keep an eye on that.
The movement of the icebergs of the 2017 calving remains from day to day is amazing (I do not know how to create a short video).  There must be strong currents beneath the ice.
Upper picture from Nov 29, lower pic from today (Dec 18, 2018)

2
Even more breakdown of the fast ice N of the Thwaites glacier tongue. EOSDIS worldview from Dec 05 (top) and Dec 18 (bottom). The dark signature that goes from the tip of the broken fast ice to the Thwaites ice tongue is probably partly open water (??)

3
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: Today at 06:47:34 PM »
I think we all should wait a couple of days until the measurements are (then hopefully) settled again.

4
The ice shelf west of the Thwaites ice tongue has lost its tip last week. Eyeballing the area it has lost around 60 km². The remains were rapidly transported to the lower left (W-NW direction). See attached images, the upper one from Dec 05, 2018, the lower one from Dec 13, 2018. Both are from EOSDIS worldview. The black line represents the borders of the ice shelf around 2010.

5
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 07, 2018, 06:19:19 PM »
By the way, I believe that the above is the explanation for the "stall" since 2007: the shallow parts have entered a new era (system change) but the Central Arctic has not. When it will do so, I do not know. It could be next year (I very much doubt it ) but it also might stay like that for another 30 years
Please check my 5 year averages I posted yesterday in the "latest PIOMAS" thread. There is no stall, only the volume has not further decreased in the years 2014-2018 compared to 2009-2013. (Re: Latest PIOMAS update (December)
« Reply #2680 on: December 06, 2018, 11:00:25 PM )

6
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 07, 2018, 06:07:28 PM »
Stephan, can you extrapolate to 1M km2 of extent as well? The "nearly ice free" criterion.
Here is the table (the right one with extrapolation to 1M).
I did it only for extent as I am not sure which volume should be attributed to the "1M km²" extent. The values are (of course) lower by 6 to 28 years.
The steeper the slope ("stg") the smaller is the difference until 1M is reached in comparison to 0M km²

7
Arctic sea ice / Re: Latest PIOMAS update (December)
« on: December 06, 2018, 11:00:25 PM »
I just did some big data treatment on extent, volume and thickness [Dicke], divided into 8 packs, each of them including five years, to look for the long-term trends on extent, volume and thickness of Arctic sea ice. To do this I calculated the average of 1979 to present for every month and averaged the deviations for each month ("Abw." in the graph) for each of the five-year-packs of these three measures.
Whereas extent seems to decrease more or less constantly in each five-year period, volume doesn't do that in the same fashion, thus thickness (calculated from division of volume by extent) also follows a more step-wise decrease than a "smoothy" one. For a better visualisation I used a second (right) y-axis for the deviation of volume.

See attached graph.

8
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 06, 2018, 10:24:14 PM »
It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen] and thickness [Dicke] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times. November value now includes 2018. In contrast to October (see my post on Nov. 05) November 2018 showed a rapid freezing higher than average which also results in values above the linear trend line from 1979 to 2018. This results in slightly higher values of when zero will be reached, but not much of a difference compared to last year.
Please note that this is not a forecast but a trend!
See attached table.

9
Arctic sea ice / Re: Poll: year-end JAXA extent ranking
« on: December 06, 2018, 07:41:01 PM »
I prefer not to change my opinion, therefore I didn't change my vote (like I also didn't in the poll about the JAXA extent minimum for Sept. 2018).

10
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 03, 2018, 09:43:25 PM »
Maybe this comes from the fact that the average of 1979-2018 has its "centre" around the late 90s. Another reason may derive from the higher melting in summer / early autumn since 2007 which produces negative spikes (Aug/Sep/Oct) in the last decade (higher negative anomaly for these months) and vice versa in the 80s (high positive anomaly for these months in the early part of the graph).
Please note also that these data are not smoothed at all.

I checked in the graph whether a change in slope occurred:
1979-2004 it is around -0,039x, 2005-2018 it is around -0,042x (with a very low R²), probably a too small difference in slope to declare this as being real.

11
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 03, 2018, 07:44:42 PM »
It is time for my monthly update of deviations in sea ice extent compared to the long-term trend.
November 2018 (9.81 mio km²) saw a much smaller deficit (0.70 mio km² less than the November 1979-2018 average which is 10.51 mio km²) than October 2018. This is mainly due to the massive and fast freezing, especially in the first half of November (see details in this thread). Therefore the strong spike of October 2018 has been just a spike.
Compared to the long-term trend (blue thin line) the ice extent in November 2018 is above by around 0.31 mio km² (the last month actual sea ice extent has been above this linear trend line was July 2018).
See attached graph.

12
Arctic sea ice / Re: "Stupid" Questions :o
« on: November 30, 2018, 05:02:12 PM »
Where’s the science to backup this 1.5c/2c bs. All the science I can find on 400+ppm CO2 in the atmosphere before present says the global average temp was 4-6c higher than today. We’re told now that if we follow some path we can hold the rise to 2c or below. Several million years back approximately 400 ppm+/- meant 4-6c more and yet that does not apply anymore. Why not? Did the physics change? If we stop adding CO2 to the atmosphere now, is the 130ppm extra going to fall out in short order? Our sinks have been crippled to within a centimetre or so of functioning at all, but somehow if we stop adding now we will reach equilibrium at 1.5c-2c. What kind of logic is this!? 400ppm = 4-6c full stop. What changed or more likely what am I missing?
Another answer may be the time frame until the temperature is reached. Scientists agree that the time needed for a new temperature equilibrium after a (sudden) change of CO2 is measured in many centuries or millenia. Many of the publications in radio or TV look at the time until the year 2100. If you think about the energy needed to melt ice this time lag is easily explainable. Responsible scientists always say that - if nothing is done about a reduction of GHG emissions and no geoengeneeric means are taken to put the CO2 out of the atmosphere, global temperatures will continue to rise beyond 2100 until 2-3°C above preindustrial with a CO2 content of 410 ppm.

13
Glaciers / Re: Glaciers worldwide decline faster than ever
« on: November 22, 2018, 10:27:15 PM »
Thanks!!

14
Glaciers / Re: Glaciers worldwide decline faster than ever
« on: November 22, 2018, 08:25:10 PM »
In which part of Russia (probably on one of its Arctic Sea islands ?) is this Vavilov glacier/ice cap located?

15
Arctic sea ice / Re: Poll: year-end JAXA extent ranking
« on: November 22, 2018, 07:53:05 PM »
I think the JAXA extent at the end of this year will be around 12.5 M km² which is in the bin 4-7 that I clicked.

16
Thank you for having you back. We have missed your contributions.

17
Arctic sea ice / Re: Arctic Image of the Day
« on: November 15, 2018, 06:46:17 PM »
As a man living in Germany it is hard to imagine to have only twilight around noon. The days here are also shorter now as in summer, but here sunset is around 5 PM.

18
Antarctica / Re: PIG has calved
« on: November 13, 2018, 07:35:23 PM »
All,

Due to Neven's management style in this forum I have decided to stop posting here,

Sayonara,
ASLR
This is really hard. Is there a chance that you change that decision? We need you here!
Anyway, thanks a million for your posts, your well-researched information and for giving us the opportunity to share your experience and knowledge.

19
Antarctica / Re: PIG has calved
« on: November 11, 2018, 07:45:04 AM »
I think we all should thank Wipneus and ASLR for important and impressive contributions to this thread.
PIG / PIIS seems to be the canary in the coalmine concerning the WAIS stability and must be continuously observed.

20
Arctic sea ice / Re: Arctic Image of the Day
« on: November 09, 2018, 07:37:49 PM »
Thanks for that impression from this remote location. I see the sun must be very low above the horizon. At which local time was this photograph taken?

21
Antarctica / Re: PIG has calved
« on: November 09, 2018, 04:54:25 PM »
Landsat delivered a cloud-free image of the PIG and the recent calving, now officially named B-46 (as long as it does not disintegrates into small pieces ). The image is attached at 60m/pix.

The arrow points at a linear feature, that may be the next big crack. This is shown in detail, resized to 7.5m/pix and contrast enhanced.

A cloud-free Sentinel 2 image would be very nice now.
Would you mind to combine this photograph with the one you posted on Reply #767 on: September 21, 2018, 09:11:33 AM? Is this the same crack or a new one?

Thanks a lot!

22
Arctic sea ice / Re: Latest PIOMAS update (November)
« on: November 07, 2018, 07:05:36 AM »
Thanks Juan for the tables. Oct 2018 is the first month since Aug 2017 with a decreased volume compared with the same month a year ago.

23
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: November 06, 2018, 09:22:11 PM »
Thanks for the interesting video. :)

24
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: November 05, 2018, 09:28:19 PM »
It is time for my monthly update of deviations in sea ice extent compared to the long-term trend.
October 2018 (6.06 mio km²) saw a massive deficit (2.02 mio km² less than the October 1979-2018 average which is 8.08 mio km²). Therefore the graph shows a strong spike into the negative direction; in the earlier years this spike was mostly attributed to September. It is the highest negative anomaly since October 2012 and the fourth biggest negative anomaly.
Compared to the long-term trend (blue thin line) the difference is only 0.87 mio km² - in the background of an ever smaller ice extent this anomaly is not as big as the above figure of 2.02 mio km² might suggest.
See attached graph.

25
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: November 05, 2018, 08:52:56 PM »
It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen] and thickness [Dicke] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times. October value now includes 2018, and BOE for October seems to appear much earlier than extrapolated last year (up to 9 years difference than last year (!), see my last posting on Sep 09 in this thread), mostly due to the late minimum in September 2018 compared to 2017 and the delayed refreezing in the first half of October (see for details the sea ice area and extent thread). According to thickness October is the earliest month of the year compared to all other months.
Please note that this is not a forecast but a trend!
See attached table.

26
Arctic sea ice / Re: Global sea ice area and extent data
« on: November 04, 2018, 08:29:45 AM »
So, finally the 2018 curve comes very close to the 2017's curve and leaves 2016 as an exceptionally low year well behind it. I wonder whether the high arctic gains will stop after most of the Central Seas have now been freezing over.

27
Antarctica / Re: PIG has calved
« on: November 02, 2018, 05:21:39 PM »
The latest calving event made it into the scientific news in the show "Forschung aktuell" of "Deutschlandfunk", a nation-wide public information radio station.

28
Antarctica / Re: PIG has calved
« on: November 01, 2018, 10:01:50 PM »
ASLR,
Thanks for the explanations, figures and information.
Stephan

29
Antarctica / Re: PIG has calved
« on: October 30, 2018, 09:25:07 PM »
Stef Lhermite also summarizes larger calving events in his blog. I paste them in here to get an overview of the accelerating rate of these calving events:
"In early 2000 large PIG calving events happened every ~5 yrs (2001, 2007, 2011), but since 2013 there were 4 of them (2013, 2015, 2017, 2018). Consequently, the glacier front retreated strongly from the 1972-2013 range and it is now ~5km further inland than in 2015-2017"
(Bad news, aren't it?)
I ask myself, whether there will be some new cracks developing in the ever faster flowing and stretching ice stream this austral summer which prepare another greater calving event next year...

30
Antarctica / Re: PIG has calved
« on: October 30, 2018, 08:35:48 PM »

Stephan,

While your questions are posed to Wipneus, I will offer my following opinions:

...
Best,
ASLR

Thanks for your opinion and for the link to various smaller and larger ice shelves around the Peninsula.

31
Antarctica / Re: PIG has calved
« on: October 29, 2018, 07:52:50 PM »
Thanks Wipneus. Great job, good anmation.
I wonder about the structures left above "2018". Is that ice mélange or smaller areas of almost open water between the ice?
I also wonder about the SW tributary. Is there an acceleration detectable?

32
Antarctica / Re: PIG has calved
« on: October 26, 2018, 06:06:18 PM »
Thanks for that link. Eyeballing the calving fronts after big calving events they seem to be at almost identical positions. Wonder whether this holds true for the next big calving event...

33
Antarctica / Re: PIG has calved
« on: October 26, 2018, 05:24:13 PM »
...
On the other hand, if the upstream movement of the calving front is the thing to worry about than I'm not so sure.

Would it be possible to overlay or animate pictures to show the calving front movement of the last years to have a rough idea whether, and if, how far it has moved inland?
Thanks in advance Stephan

34
Antarctica / Re: PIG has calved
« on: October 25, 2018, 06:10:56 PM »
Thanks a million for this important animation. I wonder whether this is just another major calving event or whether it is the beginning of the complete collapse of the PIIS.

35
Antarctica / Re: PIG has calved
« on: October 24, 2018, 10:23:47 PM »
Have all the ice bergs in the open sea disappeared or were they outside of this photograph's frame?

36
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 22, 2018, 08:26:51 PM »
Does anyone know which area Climate Reanalyzer uses when it comes to "2m Temperature Anomaly" in the Arctic (e.g. today it is +3,1 °C)?

37
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 22, 2018, 06:33:46 PM »
Do you have a graph of the previous years, rather than just some average line?
You can watch every single year here: http://ocean.dmi.dk/arctic/meant80n.uk.php
and the anomaly here: http://ocean.dmi.dk/arctic/meant80n_anomaly.uk.php

38
Arctic sea ice / Re: Global sea ice area and extent data
« on: October 22, 2018, 06:29:33 PM »
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?
Statistically you can expect another fortnight with ever decreasing global sea ice increases. So it may well be that 2018 shares 2016's development. But the variability is high; slower than average melting around Antarctica and higher than average freezing in the Arctic will lead 2018's path more into 2017's direction.
Anyway, the 4 sigma deviation is shocking...

39
Thanks for that information. Do you have a guess how many km² were lost in that last calving?

And, second question: I heard that Jakobshavn Isbræ ice flow has sped up remarkably in the late 1990s and in the 2000s. Has it been stable since then or is the ice speed still increasing?

40
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 16, 2018, 09:29:35 PM »
Thank you for your comments.

In a way, it puts pressure to do it daily. Sometimes I just want to go to sleep earlier or sometimes I just want to do other things.

So, what I going to do is to reduce the number of posts on a weekly basis, but I will do it at least four or five times during the week, on the freezing season. On the melting season, I become an ADS-NIPR addict (I can’t wait to see what is happening, so I hope to do it seven days a week). :D

P.S. Feel free to post yourself if you find some delay on my posts. I think that the last value and the daily change will be enough.
Dear Juan,
your proposal is alright with me. Please feel free to take some days off - I also can't visit this forum on a daily basis. Every of your posts is welcome.

41
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 16, 2018, 08:19:46 PM »
I also appreciate Juan's posting in the morning (before I go to work) and gerontocrat's posting in the afternoon when I return from my office. I kindly ask you to continue to present your daily analyses on sea ice extent and area.
Stephan

42
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 14, 2018, 09:51:50 PM »
Yeah, I've dabbled with google sheets and find them wonky and not as powerful as excel, but their sharing features seem excellent.

Just as a test I've created a new account, and uploaded the excel sheets I'm currently working on. I set it to share with anyone with the link.

https://docs.google.com/spreadsheets/d/1T46iX6HYG3j1umPZFlxRrjDudGmfccg3cHparR7OOgw/edit?usp=sharing

Maybe something like this can be useful?
This is very useful. Thanks.
Which sea is meant in row C "Ocean"?

43
Antarctica / Re: Sea Ice Extent around Antarctica
« on: October 14, 2018, 11:43:21 AM »
I am not completely convinced that the melting start is too late this year. The daily change wobbles around the blue polynomial line.
I wonder whether a "2016 like" melting will set off soon or whether a more moderate/average melt season will be in the pipeline. This will also decide whether the GSI area/extent graph will follow the very low 2016 line or the higher 2017 line.

44
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 14, 2018, 11:36:12 AM »
May I make a proposal for us all:
Many people here follow ASI extent, area and volume (monthly and daily), some of us even "sea wise" and use NSIDC, JAXA, PIOMAS or other sources to feed their personal excel sheets for further calculations and extrapolations.
Wouldn't it be good to share a common and open data basis where some of us add the necessary information on a daily basis that is open for everyone. This would avoid multiple individual data acquisition and processing.
What do you think about this proposal?

45
Antarctica / Re: PIG has calved
« on: October 13, 2018, 10:10:00 PM »
Wipneus, thanks a million for your contributions in this thread. I discovered this and I am fascinated by the development.
Do you have an actual glacier velocity of the PIG → did it further increase this year?

46
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 12, 2018, 09:18:20 PM »
(This post is in the wrong thread but it must be said)
Here in Germany we suffer almost without exception from a too warm and too dry summer since beginning of April. We had almost no rain throughout June to October with a lot of crop failure and forest fires. And tomorrow daily max. temp is forecasted to be 27-29°C almost nationwide. Many people are alarmed, and the green party is really up in public polls. Diesel discussion and the end of coal mining is in every news show...

47
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 12, 2018, 07:47:44 PM »
If this becomes true, it should be named "Abrupt Climate Change" for Bering and Chukchi Sea.

48
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 12, 2018, 07:46:14 PM »
Once again ... it's so good to have you back here.
Except for Greenland Sea almost all other seas seem to refuse growing in area, and they ought to do so now for weeks. Something is wrong, at least much delayed.

49
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: October 12, 2018, 07:31:37 PM »
With missing fixed points like mountain ranges it is hard to say whether the upper (northern?) part is moving away from the lower (southern?) part or vice versa. Does anyone know?

50
Arctic sea ice / Re: Global sea ice area and extent data
« on: October 12, 2018, 05:48:10 PM »
This is probably another spike, such of those we see almost every year (see e.g. the green curve for 2017). I guess global sea ice data will return down to record values next week.

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