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Messages - Stephan

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1
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 29, 2020, 06:36:50 PM »
I add an animation with today's evolution: the ice mix above the Crescent is gone, the Crescent itself is taking off and the other iceberg is going to follow...
The crescent and her little sister south of her are too young, too small and too unexperienced to be set free into the wide wilderness of the Southern Ocean. Someone should go there and help them to stay close to their birth place...  ;)

2
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 29, 2020, 04:16:21 PM »
To reply #2262:
Is it just the low resolution of the second picture of your gif that fools me or has Cork III already left its connection to the SIS?

3
Melting season makes a little pause as Freya Gletscher Webcam shows (May 26)

4
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 28, 2020, 05:37:42 PM »
I think, grixm's post referred to my posting 126, in which I was surprised of the re-increase of CO2 values the week before.
Posting 126 (as all other of my Sunday evening CO2 postings) refer to the NOAA website, on which CO2 average concentrations and its annual increase for the just passed week are published. So each individual annual increase I report contains the weekly values. Once a month (on the 5th) NOAA publishes the monthly averages. I report this in an extra posting.
Link to NOAA: https://www.esrl.noaa.gov/gmd/ccgg/trends/index.html

5
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 27, 2020, 10:51:19 PM »
I wouldn't put too much emphasis in this fact. The day-to-day variation is larger than the almost flat long-year trend mid to end May. But the downward trend should proceed from mid June on. Until then anything is possible, even a slightly higher value than on May 3 or 25.

6
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 27, 2020, 09:31:56 PM »
...and May 25th with 418.1 ppm, tied with May 3rd, 2020, which was the highest daily average value ever measured so far. So we have two maxima this season?
Anyway, with the average of 414.2 ppm last year, we are heading towards an annual increase of above 2.5 ppm, unless a downward trend begins.

7
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: May 27, 2020, 06:10:35 PM »
Bering Sea: Great losses of 10% of the ice area every day since May 20th.

8
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 26, 2020, 09:00:38 PM »
The red line is the major calving including Cork in February 2020. The yellow line includes minor calvings including Cork II in March and April 2020. The orange line summarizes the double calving of the Point, the Keystone, the Crescent and the northern part of SIS from this weekend.

PS: Apart from Cork III and Point 2 there are no other named places left. Let's see how these icebergs, rifts and edges develop to find a common understanding by giving them names and/or numbers in the future.

9
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 26, 2020, 05:44:52 PM »
paolo,
I guess you can read my mind. This picture was one I planned to make and to post here. Thank you for doing that so well.  :)

10
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 25, 2020, 08:01:41 PM »
I think the SWT is in a dangerous position. It now has two calving fronts that are directly attackable by the ESE → WNW directed current. In addition there are cracks (or precursor cracks) visible. I wouldn't be too surprised if relatively soon another calving completes the series. At least at the red line a calving will happen in the not too distant future.

11
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 25, 2020, 05:42:02 PM »
Here is a 6-day high resolution GIF focused on the Southern Ice Shelf (and with improved alignment) from May 17 and 23 followed by today's low-resolution calving.  You can see the middle rift ("1.5") spreading in the second image, but other than that no sign of the impending calving event.
Thank you baking for this information. I think a new rift sR4 is visible in the second last picture.

12
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 25, 2020, 05:39:24 PM »
It is incredible. Another major calving two days after a major calving. Will there be major calvings every two hours in the next future? When does this stop?

13
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 24, 2020, 08:58:36 PM »
Last year there was a permanent flow of sea ice through the Nares Strait into Baffin. This year up to now the arch is still intact and the sea SW of it is already completely ice-free. When I turn to gerontocrat's postings in the area/extent thread I remember that Baffin Sea has much less ice than usual. Would a permanently open Nares Strait lead to higher Baffin Sea Ice or is the input of ice through the narrow Nares Strait negligible?

14
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 24, 2020, 05:06:33 PM »
The last months saw a faster and more intense calving at the SW edge of PIIS-MIS, due to the lack of stability around the zone of destruction (ZOD) at the south shear margin (SSM/SIS) and probably due to a stronger current beneath. But minor calvings along Evan's Knoll on the NE edge have always made up a little bit for that difference. One must also take into account that on the NE side there is also an issue with structural integrity and thickness because of the speed differential between MIS and the NE-IS.
In the end I think that a slight preference for calving on the SW side will continue until the upper end of the ZOD has reached the calving front. But I can not imagine a diagonal calving front.

15
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 24, 2020, 04:55:08 PM »
Outlook:
Next week last year had an average of 414.8 ppm. Taking into account the actual downsloping curve I wouldn't be surprised if the annual increase goes even further down than this week.
It is time for the weekly Mauna Loa CO2 posting.
It comes as a surprise, but two weeks ago was not the weekly maximum, this week is slightly higher. We have a broad maximum this year. Therefore the annual increase has risen to 2.25 ppm, the ten year average increase is 2.35 ppm. The values:
Week beginning on May 17, 2020:     416.97 ppm
Weekly value from 1 year ago:          414.72 ppm
Weekly value from 10 years ago:      393.46 ppm
Last updated: May 24, 2020

Apart from yesterday ("unavailable") the whole week had constant CO2 values with a very small intra-day variability.

Outlook:
Last year next week had an average of 414.2 ppm. When the plateau that has been reached now still holds on, then the annual increase can even move up a little further. It is impossible to say on which date finally the annual cycle with decreasing daily values will have its onset.

16
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 23, 2020, 05:36:56 PM »
It may be a little bit OT, but I'd like to know whether Eric Rignot is following the discussions in this forum. For me he was the one to have a good explanation of what is going on (what is going wrong, actually) with PIG and Thwaites. I remember some of his presentations years ago. Today the situation is much worse than then. The ice shelf is thinner, faster, shorter, and the ZOD didn't exist years ago...

17
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 23, 2020, 04:02:05 PM »
P2, now becoming the most exposed part of MIS, has increased its distance to Cork III, letting the gap between them be a little wider. I expect a flowing out of the unprotected icebergs between P2 and Cork III in the near future. Then Cork III will act like Cork II did some weeks ago and prevent the mélange upstream from flowing out into the sea.
P2 does look fragile and full of little cracks. I do not know how long it can withstand the forces of wind and currents.

What does today's calving mean for MIS's future? MIS has lost some weight, some area and some resistance. Will this loss lead to a speeding up? Has the bigger calving of February already increased MIS's flow speed? Any ideas?

18
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 23, 2020, 12:54:44 PM »
How large is the latest iceberg and is it big enough to be numbered?

19
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 23, 2020, 11:43:45 AM »
A very short story about the newly named R1...
On the one hand fascinating, how fast things happen, on the other hand frustrating and alarming. How much further will MIS calve until it finds a state which is stable at least for one year ???

20
- in the SouthWest melt is associated with precipitation - but as  rain.
Wet and not so warm times are expected in S Grønland. Forecast for Narsarsuaq for May 23 - June 05, 2020.

21
On which dates were the two pictures you used for that gif taken?

22
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 22, 2020, 08:34:09 PM »
My impression is that the rotating "keystone" pushed its Northeastern corner against the row of icebergs between it and the point and the "point" gave way due to it's being pushed from an unusual direction.  If the keystone remains in place, I think it will continue to push in the same direction and the calving will be within the next week or two.  If the keystone or the any of the other bergs in that line pop out before then, it could take longer to complete.   In any case, it is hanging on by a thread.
The question that arises is whether the keystone and its neighbours, all of them icebergs in the mélange, do have the structural integrity and strength to force the big MIS to widen R1 and lead to a faster forward move.

23
Greenland and Arctic Circle / Re: Greenland 2020 Melting Season
« on: May 22, 2020, 05:38:49 PM »
And, meanwhile in the bigger picture, another consecutive day of mass loss...
...in previously untouched territory (knowing that the grey shaded area does not cover the maxima (or minima) that were observed so far).

24
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 22, 2020, 05:36:56 PM »
Thank you paolo for that update. Faster than expected, I would say, is the formation of (new) R1. On the other side of the mélange, the crescent seems to be untouched by the new development.

25
Greenland and Arctic Circle / Re: Greenland 2020 Melting Season
« on: May 21, 2020, 10:17:59 PM »
I just checked the historical pictures from Freya Gletscher webcam and looked for melt pond formation dates:
2016 first melt pond further downstream June 11, no melt pond at that place at all through August
2017 first melt pond further downstream June 1, melt pond at that place June 6
2018 no melt pond in May, and then - camera not working for a while...
2019 melt pond at that place May 26
So in this little race 2020 is the winner for being as early as never since 2016.

26
Arctic sea ice / Re: The 2020 melting season
« on: May 20, 2020, 06:03:47 PM »
RE long-term arctic sea ice volume deviation chart
https://forum.arctic-sea-ice.net/index.php/topic,2975.msg264869.html#msg264869

     Thanks Stephan.  I don't have the foresight to make Sept. predictions, but I'd bet dollars to doughnuts that the upside anomaly in the current chart will fall back a lot closer to the long-term trend line when the May 2020 volume data are included.
The statistics say that it is likely that Sep (and Jul, Aug, Oct) volume anomaly will be below the linear trend line. This has happened from 2009 on, with exceptions in 2015 and 2018. In those two years the volume anomaly was around the long term linear trend line.

27
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: May 20, 2020, 05:40:59 PM »
Sea Ice Area analysis "relative area wise" May 06-May 19, 2020.
The melting has not started yet in CAA, CAB and ESS. Minor losses (5-8%) in Laptev, Beaufort and Hudson. Greater losses (10-19%) in Chukchi, Baffin, and Kara. Big losses in St Lawrence (-28%). Huge losses in Barents (-42%), Bering (-42%) and Okhotsk (-44%). A little gain in Grønland Sea, not because of re-freezing, but caused by permanent export from CAB through the Fram Strait.

28
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: May 19, 2020, 10:45:55 PM »
Here is my long-term arctic sea ice volume deviation chart. Since December 2019 the values are above the long-term linear trend lines. These differences are larger compared to the early months in 2019. So the slope has slightly decreased compared with early 2019, when I published this graph the last time.

See attached graph.

29
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: May 19, 2020, 10:30:52 PM »
It is time for the monthly update of my extrapolation when the extent [Ausdehnung], volume [Volumen], thickness [Dicke] and area [Fläche] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times (valid for volume and thickness, not for extent and area in the winter months). The April value now includes 2020.
Volume and thickness for April 2020 lie well above the long term trend lines whereas area and extent dip slightly below it. The "BOE numbers" increased by averaged 1 year (thickness) and did not change (volume and extent) compared to April 2019.
The order (earlier → later BOE) generally is volume < thickness < area < extent.

Please note that this is not a forecast but a trend!
See attached table. stg = slope.

30
Arctic sea ice / Re: The Arctic for Amateurs and Newbies
« on: May 19, 2020, 09:00:59 PM »
This year I'm seeing that bottom-fast ice again (bottom right corner), and it's doing something weird. It seems to be blocking a whole lot of ice inbetween it, and another bigger piece of fast ice.
Good catch, freegrass. Something identical happens around B-22A NW of Thwaites Ice Tongue in Amundsen Sea, West Antarctica all the time. Some little icebergs ground and block the escapeway into the ocean of many other icebergs. A natural dam, so to say, for some while ... until melting from below starts to be effective or violent storms come across.

31
Yet along the rapidly eroding coastlines of the Arctic Ocean, which make up 34% of the Earth's coastlines, whole stretches of the coast simply collapse, sink or slide into the ocean, including the previously frozen organic carbon.
Is there any number available, how many kilometers of arctic coastline is affected by erosion caused by thawing of permafrost soil? I guess at least some portion of arctic coastline is bare rocks having not much soil available for erosion processes.

32
Antarctica / Re: Thwaites Glacier Discussion
« on: May 18, 2020, 06:34:30 PM »
I want to remind you about my posting #256 in the Iceberg Thread where I analysed the movement of B-22A from Jan to March 2020. https://forum.arctic-sea-ice.net/index.php/topic,2245.250.html
In that analysis I measured the movement of the five corners of that iceberg, where its SW tip (the one that recently broke off) was the fastest moving part. This indicates that it was not grounded at that corner.

33
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 17, 2020, 05:36:08 PM »
Outlook:
Last year next week was at 415.3 ppm, the maximum for 2019. I expect an annual increase of 2.0 ± 0.25 ppm, which would represent the highest weekly average for this year.

The Sunday evening posting series on Mauna Loa CO2 levels is back again.

Week beginning on May 10, 2020:     416.79 ppm
Weekly value from 1 year ago:          415.31 ppm
Weekly value from 10 years ago:       392.68 ppm
Last updated: May 17, 2020

The annual increase reduced markedly to just 1.48 ppm. The maximum for 2020 has passed, one week earlier than last year, which explains my "not so good" guess from last week. It is also much lower in comparison with the last ten years (average annual increase 2.41 ppm). This also makes it clear that the benchmark of 420 ppm has not been reached, not even in an hourly average.

Outlook:
Next week last year had an average of 414.8 ppm. Taking into account the actual downsloping curve I wouldn't be surprised if the annual increase goes even further down than this week.


34
Thank you Niall for the work to put this data altogether. To me it looks like a wild up and down and like random which model is tendentially higher or lower than others. Would you mind to calculate monthly or three-months averages to find out which model may be an outlier?

35
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 17, 2020, 02:59:54 PM »
Proposal: We should call it sR3. There is obviously no space for an extra "sR2.5"

36
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: May 17, 2020, 01:41:52 PM »
Thank you for that update.
I was about to ask whether there would have been a week without any further (mini-/micro-)calving on PIIS and its neighbours, but now this question became obsolete.

37
Arctic sea ice / Re: Global sea ice area and extent data
« on: May 17, 2020, 07:34:51 AM »
I evaluated the actual JAXA extent data and compared it with the decadal averages. The actual Arctic Sea Ice Extent was reached 6 days later than today in the 2010s, the actual Antarctic Sea Ice Extent was reached 4 days earlier in the 2010s. This is in sum a difference of 10 days.
Compared to the other decades following differences were observed:
2000s: Arctic +18 days, Antarctic - 7 days, sum = 25 days
1990s: Arctic +29 days, Antarctic - 6 days, sum = 35 days
1980s: Arctic +39 days, Antarctic - 2 days, sum = 41 days
This means more open waters and more warming potential by insulation in the Arctic compared to earlier decades, and more available potential freezing heat in the Antarctic.

38
Arctic sea ice / Re: 2020 Melting Season Predictions
« on: May 15, 2020, 09:44:42 PM »
I wouldn't go for a new minimum record in September. I guess the minimum JAXA value will be something around 4.1 ± 0.15 M km².

39
Greenland and Arctic Circle / Re: Greenland 2020 Melting Season
« on: May 14, 2020, 10:47:08 PM »
Forecast for Narsarsuaq, S Grønland mid-end May 2020.
Mild, dry and sunny. Melting season.

40
Antarctica / Re: Thwaites Glacier Discussion
« on: May 13, 2020, 01:05:14 PM »
Thank you oren (??) for having sticked three of the most important threads about Antarctic Ice.

41
Arctic sea ice / Re: Global sea ice area and extent data
« on: May 13, 2020, 07:43:00 AM »
I evaluated the actual JAXA extent data and compared it with the decadal averages. The actual Arctic Sea Ice Extent was reached 2 days later than today in the 2010s, the actual Antarctic Sea Ice Extent was reached 4 days earlier in the 2010s. This is in sum a difference of 6 days.
Compared to the other decades following differences were observed:
2000s: Arctic +12 days, Antarctic - 6 days, sum = 18 days
1990s: Arctic +24 days, Antarctic - 5 days, sum = 29 days
1980s: Arctic +34 days, Antarctic - 2 days, sum = 36 days
This means more open waters and more warming potential by insulation in the Arctic compared to earlier decades, and more available potential freezing heat in the Antarctic.


42
The door is open, yes. But probably not just because the melting has arrived there... ;)

43
Antarctica / Re: Thwaites Glacier Discussion
« on: May 12, 2020, 07:50:30 PM »
Thank you baking for that information. It is the same observation I made months ago, that there is a center of clockwise rotation close to the NE corner of B-22.
I wonder whether the new SW corner of B-22 may force the broken-off SW part into deeper seas further west of it. You can see the movement of the broken-off part. Otherwise it will stay there almost grounded for a longer period of time.

44
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 12, 2020, 06:59:14 PM »
Outlook:
The first week of May 2019 averaged at 414.3 ppm. I guess the actual peak will flatten out. We should expect an annual increase of 2.75 ± 0.25 ppm.
The latest weekly average of Mauna Loa CO2 is available:

Week beginning on May 3, 2020:     416.83 ppm
Weekly value from 1 year ago:        414.11 ppm
Weekly value from 10 years ago:     392.98 ppm
Last updated: May 12, 2020

The annual increase is 2.72 ppm, almost exactly in the expected range. The 10 year average is lower (2.38 ppm) than this week's increase.
This week saw high intra-day, but low inter-day variations. It seems that we are close to the maximum. The highest daily average was probably reached on May 3rd (418.1 ppm). It seens unlikely that the border of 420 ppm can be achieved this season. But 2021 will definitively go beyond that benchmark.

Outlook:
Last year next week was at 415.3 ppm, the maximum for 2019. I expect an annual increase of 2.0 ± 0.25 ppm, which would represent the highest weekly average for this year.

45
Science / Re: Where are we now in CO2e , which pathway are we on?
« on: May 10, 2020, 09:36:57 PM »
Said and done.
I recalculated the data, now turning from CO2 equivalents into Delta radiative forcing. I checked my calculations with the NOAA table. It worked well for CO2, CH4 and N2O. I didn't find any conversion formula for SF6, therefore I used a factor from the fourth IPCC assessment report https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html where I found the factor 0.52 (*10-3) with which the SF6 concentration shall be multiplied to give its additional warming potential. As SF6 has a very low in concentration it does not really matter. The distribution among the gases are:
CO2 74 %
CH4 18 %
N2O  7 %
SF6   0.2 %
In addition I could add the years 1979-2001 for all four "NOAA gases" to my spread sheet. :)

I hope you are satisfied with the attached graph:
(linear fit again doesn't work perfectly due to the acceleration of the concentration)

46
Science / Re: 2020 Mauna Loa CO2 levels
« on: May 10, 2020, 06:27:27 PM »
It is Sunday evening and time for my weekly update of Mauns Loa CO2 levels. But - there are no new weekly averages available tonight. I return to this point as soon as I can share the data with you.

47
Science / Re: Where are we now in CO2e , which pathway are we on?
« on: May 10, 2020, 01:15:52 PM »
Thank you Steven. I saw that calculation and the formula (thank you for that link), but I thought it could be simpler than that.
Anyway, I will introduce these formulae into my spreadsheet and I hopefully will end up with the same results (excluding CFC etc.) as presented in Table 2 of that link.

48
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: May 10, 2020, 11:15:38 AM »
Evaluation "relative area wise" from Apr 21 to May 08, 2020.
No changes in most of the Central Arctic Seas. The only relevant differences were detected in ESS and Kara Seas (each -6%).
All of the Peripheral Seas show losses. The last of the seas (Hudson) now also joined the melting season. The list is dominated by Okhotsk (-63 %), followed by
Bering (-25 %) and Barents (-17 %).
Hudson, Baffin and Grønland Seas lost 8-9 % of their ice area.
More or less irrelevant is the 5 % loss of St. Lawrence which has almost melted completely.


49
Antarctica / Re: PIG has calved
« on: May 09, 2020, 10:32:55 PM »
Thank you paolo for this great animation of 18 years of disintegration and calving of PIS/PIIG/MIS.
What seems unprecendented to me is the formation of the Zone of Destruction along MIS' border with the SIS around 2018.
What is remarkable is a big "calving" event around 2010/11 much further upstream on the border MIS/SIS, probably close to the grounding line. This calving zone seems to be still active, and the area where it happens also looks like it might become a new Zone of Destruction. When this part will not re-freeze in a proper way it will become a new zone of instability, if it reaches the calving front. This outlook does not look good in general...

50
Science / Re: Where are we now in CO2e , which pathway are we on?
« on: May 09, 2020, 08:28:41 PM »
Steven,
I know that and I am aware of that. There has been already a lengthy discussion about this topic maybe two pages above in this thread.
Anyway, if there would be a formula (but as far as I can remember there is none) to add concentrations of greenhouse gases into a "global GHG CO2 equivalent" I would recalculate my spreadsheet and present it again. If not, I will keep it for myself from now on. The smart thing about this formula would be that the easily available concentrations of the different gases could be directly converted into one CO2 equivalent.
If there is anybody to help me out - you're welcome.

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