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Messages - Stephan

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1
Antarctica / Re: PIG has calved
« on: February 17, 2019, 10:27:33 PM »
I just compared PIG February 2018 with February 2019. The western flank of it shows much more cracks and bergs within a frozen sea in 2019 compared to 2018. The area where these features appear, has grown longer and wider (circled in blue). I see this as the beginning of a further dis-integration and a preparation of more and more frequent calving events in the coming years.

I also want to correct my statement from earlier this day: One of the cracks has widened by about 50% since early January 2019. It is marked in yellowish green.

See attached pictures. And please compare the calving front which has massively moved inland.

2
Science / Re: 2019 Mauna Loa CO2 levels
« on: February 17, 2019, 10:05:49 PM »
I am very worried.
Latest results from Keeling's lab:
Week beginning on February 10, 2019:     412.41 ppm
Weekly value from 1 year ago:                     408.55 ppm
Weekly value from 10 years ago:             387.17 ppm
If I calculate correctly, the average yearly rise was ~ 2.5 ppm between Feb 2009 and Feb 2019.
The actual yearly rise is higher for many weeks now. Last week the difference grew to almost 4 ppm, and we do not have an El Niño yet. Where will this end? Will a new El Niño year push up the yearly increase to 5 ppm CO2 or even more?
I am very worried.

3
Antarctica / The Ross Ice Shelf Thread
« on: February 17, 2019, 09:04:01 PM »
I just wondered that the largest Antarctic Ice Shelf - the Ross Ice Shelf - does not have its own thread. You can see it constantly growing, almost no cracks at its northern edge, apart from two or three seemingly elder ones. And so it didn't show larger calving events for many years or even decades.
Yesterday the northeasternmost corner of it showed a minor calving, an area of around 10 x 2 km broke off, in an area already full of cracks, see attached picture.

4
Antarctica / Re: PIG has calved
« on: February 17, 2019, 02:16:37 PM »
I went back in Sentinel around 25 months ago, and at that time this rift looked almost the same as it does now.
So the answer to your bet may take a while  ;)

5
Antarctica / Re: PIG has calved
« on: February 17, 2019, 12:02:11 PM »
A new Sentinel picture of PIIS is available. I checked the actual rifts and didn't find any relevant lengthening or widening. Only a very little calving must have taken place this week (500m x 150m of ice is missing) close to the junction of PIIS and the SW tributary glacier at the same place where another calving event took place two weeks earlier.
I looked at three different features of PIIS and compared their NW-ward drift between Jan 27 and Feb 16 (=20 days). The movement of the ice was 272m, 263m and 270m, respectively, which results in a speed of ~13-14 m/day, which is in the upper range of what has been calculated earlier.

The small rift in the SW tributary has moved north by about 36 m in the same time, which shows a much smaller speed (ca. 2 m/day).

6
Antarctica / Re: Thwaites Glacier Discussion
« on: February 16, 2019, 09:39:19 PM »
In addition to my post #50 in this thread I state that most of the "outer ice field" has dis-integrated into many pieces of smaller sea ice.
I tried to cover the original area of this ice field in orange. It seems to have "grown" in the last days, but this extra sea ice derives from the massive clean up at Pine Island Bay and Thwaites (circled in light blue) I wrote about the last days in the "PIG has calved" thread.
Below (in magenta) you see the iceberg B-22-A which moves slightly westward, on some days more in a counterclockwise manner than in a direct flow. Unfortunately this Sentinel picture is partly cloudy - but there is no better view available. The latest picture before this is from Jan 30. It shows a more or less intact outer ice field with a lot of cracks, that indicated the future collapse which has now occurred.
In the NE part of the picture is Burke Island for a better orientation.
The picture covers an area of ~ 320x175 km, so it is huge!

8
If you look at that Polarview image you can see a lot of frozen summer melt lakes on the ice sheet further inland. They haven't drowned through the moulins.

9
Arctic sea ice / Re: Global sea ice area and extent data
« on: February 14, 2019, 07:34:58 PM »
If the global minimum already has occurred it will be the earliest minimum (Feb 05) in the last 15 years. However, some days or even two weeks back and forth does not mean anything...

10
Antarctica / Re: Sea Ice Extent around Antarctica
« on: February 13, 2019, 10:02:53 PM »
Thanks for these analyses. It is good that you follow these data in detail.

11
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 12, 2019, 10:32:29 PM »
Last year we were wondering if the Bering Sea would have a February max (we thought that would be incredible! then it had a March max).  This year I'm wondering if the Bering Sea will have a January max, but am ho-hum about the possibility.
It looks again that Bering Sea Ice cover doesn't want to follow "normal" routes as it is declining rapidly in contrast to all the ten-year-averages. It is too early to say it has already had its maximum, but it is really possible...

12
Antarctica / Re: PIG has calved
« on: February 12, 2019, 08:13:03 PM »
The "clean up" of the fast ice in Pine Island Bay continues even faster. Today a ca. 350km² area in the northeastern part of the Bay was cleared from ice, in addition a lot of the northeastern coast. Also the SW side of the bay lost further fast sea ice. All these areas are marked in red. The big yellowish green marked feature in the center is the biggest remaining iceberg from the calving event in October 2018. Some of the freshly eroded fast ice was pushed against the eastern margin of the Thwaites Ice Tongue (marked in blue).
See attached picture.

13
Antarctica / Re: PIG has calved
« on: February 11, 2019, 08:54:49 PM »
"Clean Up" of fast sea ice in Pine Island Bay.
All red marked areas have lost fast sea ice in the last week/during the last weekend.
The areas are marked in red at the PIIS show minor calvings (see more details above in this thread). The blue marked iceberg is grounded and is located at the same place for quite a while now. I tried to indicate some names of islands and glaciers for a better orientation. The whole area contains ca. 320 x 175 km, so it is huge.
See attached graph

PS: In Sentinel some of the edges close to the slow, not really moving ice shelves show the first re-freezing.

14
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 11, 2019, 08:02:14 PM »
Stephan - can you show a graph with only the January averages for each year? I wonder if it will show a different trend.
Here it is, please note that the slope is only 60% of that of all calendar months:

15
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: February 10, 2019, 10:33:09 PM »
I just visited Sentinel images of the Brunt Ice Shelf. The Chasm 1 crack has lengthened about 2 km between Dec 29, 2018 and Feb 07, 2019. Its distance to the tip of the Halloween Crak is now only around 8 km. I wonder when these two cracks will meet and what happens thereafter...

16
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: February 10, 2019, 10:14:10 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. Volume is the first to reach zero.
Due to long unavailable data for December I present Dec 1979-2018 and Jan 1979-2019 in one new post.
As both months lay above the long term linear trend (see my posting today on the sea ice area and extent data) the slopes have decreased very slightly, leading to slightly later values compared to the two months one year ago.
Please note that this is not a forecast but a trend!
See attached table.

17
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 10, 2019, 09:53:17 PM »
Another month - and this time also another 5-year period - has passed and I provide the actual January extent data in the bigger context.
Jan 2019 had an average extent of 13.56 M km², 0.6 M km² less than all Januarys since 1979. Nevertheless the loss does not follow the linear trend line, but remains 0.3 M km² above it (red line in the graph). It is the third consecutive month with that behaviour, and I guess at least the next two months will show the same deviation.
See attached graph (if you compare it with the Dec 2018 graph you see I had to lengthen the x axis by another five years).

18
Antarctica / Re: Thwaites Glacier Discussion
« on: February 10, 2019, 08:53:22 AM »
OK, I will keep that in mind. Sorry for not having it thoroughly checked.

19
Antarctica / Re: Thwaites Glacier Discussion
« on: February 09, 2019, 10:04:19 PM »
New development at the fast ice east of Bear Peninsula and South of Iceberg B-25 B-22-A.
In-between the coloured lines (I used the same colours as in Reply #49 earlier in this thread) there are hundreds of cracks. So one might expect a further degradation and dis-integration of the fast ice.
But summer is fading rapidly and some features already show a thin ice cover, for example parts of the pale magenta coloured crack, or the blue circled area close to the open ocean.
So the late austral summer may prevent the fast ice from a complete collapse.
See attached picture.

20
Antarctica / Re: Thwaites Glacier Discussion
« on: February 09, 2019, 09:40:59 PM »
I carefully compared Thwaites Glacier cracks Dec 15, 2018 with Feb 09, 2019. A new one, around 15 km long, has formed within the last 8 weeks.
See attached figure.
I indicated some of the features so you have a better orientation. Thanks Bernard for letting us know that we should give some additional information, where exactly all these things are going on...

21
Antarctica / Re: Melt water in Antarctica
« on: February 09, 2019, 06:24:17 PM »
You were almost right with your prediction.
I just checked Amery Ice Shelf by EOSDIS and all the upper "lakes" changed their colour from blue to grey. They probably froze over during the last days.

22
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 08, 2019, 09:08:17 PM »
I just checked the 2018 sea ice area and extent data thread, but early last year gerontocrat didn't update us with daily sea-wise area data. At this time of the year Okhotsk was strongly rising, so did in parts Baffin and St. Lawrence whereas Bering strongly declined.
At this time of the year all the major central seas are more or less 99-100% covered by sea ice, and a strong increase (or decrease) in one or two of the peripherical seas may change the direction of the total sea ice area (or extent). Therefore I don't think this actual "dependence" on the Okhotsk Sea is unusual.
Maybe gerontocrat can help with figures/tables from last February.

23
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 08, 2019, 08:24:19 PM »
If Okhotsk Sea were excluded from the calculation we would see continuous losses of Arctic Sea Ice Area from 28 Jan on...

24
Thanks for sharing.
And a 'like' earned

25
Antarctica / Re: What's new in Antarctica ?
« on: February 07, 2019, 10:14:45 PM »
Thanks for sharing!
And another 'Like' earned

26
Antarctica / Re: PIG has calved
« on: February 07, 2019, 06:42:23 PM »
A new crack has developed in the last two weeks on one of the icebergs at the western flank of PIIS. It has a length of roughly 1.2 km and almost reached the eastern side of this iceberg.
See attached figure, crack marked in yellowish green.
I wonder what happens when the calving front reaches this area of already broken-up ice at the western flank of PIIS. Will this accelerate the degradation in general and lead to more little calving events?

27
Antarctica / Re: PIG has calved
« on: February 07, 2019, 05:49:51 PM »
Please compare this picture with my reply #916. The cracks were already visible at that time. I checked their length and width on Sentinel on Feb 06 with mid-January photos and they didn't change. So for a sudden calving cracks do not necessarily need to widen and lengthen beforehand...

28
Antarctica / Re: PIG has calved
« on: February 06, 2019, 10:12:45 PM »
Minor break-up of fast sea ice on the NE shore of Pine Island bay. Total are is about 15 x 2-3 km². Mostly it is young thin ice, but two packs derived from the ice shelf (marked in blue) have also disintegrated. In addition new and older cracks in that shelf are marked in orange. Probably future breaks, possibly this austral summer?
See attached figure.

29
Antarctica / Re: PIG has calved
« on: February 06, 2019, 10:05:00 PM »
Minor calving at the SW end of the PIIS, an area already designed to calve because of many cracks with the approx. size of 3 x 0,5 km has calved this week.
See attached picture.

30
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 05, 2019, 09:54:24 PM »
Slight losses almost everywhere. Did that missing ice sink in the end?   ;)

31
Arctic sea ice / Re: Latest PIOMAS update (January)
« on: February 05, 2019, 09:51:40 PM »
Wipneus - brilliant.
The original video worked finely without any problems on my laptop basing on a Windows 8 system. I am on www. using Google Chrome.

32
Antarctica / Re: PIG has calved
« on: February 04, 2019, 08:28:00 PM »
So it seems, as expected, again an increase of speed of this fastest glacier in Antarctica. Higher speed also means thinning, stretching and a more likely formation of cracks and crevasses. This is what I heard from scientists in various youtube videos. Together with the missing ice at the junction of PIIS and the SW tributary and no sea ice at the calving front a bigger calving event is likely again - probably resulting in a higher than ever calving front.
I am not a glaciologist, so please correct me if I am wrong...

PS Is there any update of the position of the grounding line of PIG?

33
Antarctica / Re: Sea Ice Extent around Antarctica
« on: February 03, 2019, 09:03:42 AM »
Thank you for this comprehensive information. But I still think that there is some more ice to melt and the less than average melt will slightly turn into an average or even an above average melt in the next three weeks.

34
Antarctica / Re: Thwaites Glacier Discussion
« on: February 03, 2019, 07:23:51 AM »
Further retreat of the ice mélange west of Thwaites ice tongue. The distance between open water and the calving front of Thwaites glacier is reduced to 15-18 km. You can also recognize that iceberg B22A is slightly moving westward - this was not visible the last months. May melting from below have thinned it so that it lost connection to some of the pinning points?
See the link (comparison of Jan 22 with Feb 02, 2019) to EOSDIS worldview
https://worldview.earthdata.nasa.gov/?ca=false&cm=swipe&cv=94&p=antarctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&l1=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2019-02-02-T00%3A00%3A00Z&z=3&t1=2019-01-22-T00%3A00%3A00Z&v=-1699945.223835678,-608838.4314290967,-1487465.223835678,-490822.43142909673

35
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: February 01, 2019, 10:41:02 PM »
If it were not for the Okhotsk Sea we would see a decline in Artic Sea Ice area the last four days...

36
Antarctica / Re: Melt water in Antarctica
« on: February 01, 2019, 08:35:10 PM »
Massive amounts of meltwater on Amery Ice Shelf. I took a Sentinel photo from Jan 22, which has less clouds than more actual ones. Today the area covered by water is even bigger than last week.
Does anyone know whether this ice shelf also has features like moulins which I know of from Greenland?

37
Antarctica / Re: Thwaites Glacier Discussion
« on: February 01, 2019, 08:20:25 PM »
I have also noticed that many of the ice bergs west of the Thwaites Ice Tongue might be grounded. Comparing day-by-day or week-by-week some of them just turn around at their position, others seem to be completely immobile. The waters must be shallow there.
If I look at the outer ice field I mentioned some days ago, it contains only few ice bergs originated from Thwaites. Therefore I think that - if sea temperature and currents are "right" - it will further disappear or move, and some of the grounded bergs in it will just stay where they are at the moment...

38
Antarctica / Re: PIG has calved
« on: February 01, 2019, 07:36:47 PM »
No problem, you're welcome   :)

39
Antarctica / Re: PIG has calved
« on: February 01, 2019, 06:27:31 PM »
This has been posted before in the Thwaites Glacier thread - Neven, could you remove this posting into the right thread? Thanks.

40
Antarctica / Re: Thwaites Glacier Discussion
« on: February 01, 2019, 05:42:09 PM »
In addition to the posting I have just made and in addition to my post from yesterday I have to report that a further new crack in the fast ice / ice mélange of Thwaites has developed yesterday.
See attached image.
Colour code: orange is the crack I have just mentioned, yellowish green is the crack I reported of yesterday and the new crack which connects both cracks is painted in pale magenta.
It seems that the whole thing is about to collapse.
Update 31 Jan 2019: The crack in pale magenta has massively widened. The whole eastern part moves to the southeast. The crack in yellowish green has not changed significantly.

41
Antarctica / Re: PIG has calved
« on: February 01, 2019, 05:10:59 PM »
A day of complete cloudlessness on Jan 31 allowed a clear Sentinel picture on the PIIS. I checked the cracks and I detected three of them. In yellowish green there is the crack (actually it is two cracks not yet connected together in the centre) I reported about some days ago. It looks quite new with sharp edges. In brown there is another crack which looks much older and which is filled with snow. This is probably the crack wipneus and ASLR mentioned some months ago. The third crack in pale magenta is the one close to the calving front. It has not changed in width and length since last week, but due to the rapid movement (has anyone a number of the speed of PIIS at hand?) it has changed its absolute position.
See attached picture.

42
Antarctica / Re: January Poll 2019: JAXA Antarctic minimum
« on: January 30, 2019, 08:30:44 PM »
I keep on with my 2.08 M km² I bet for some weeks ago. I think there will be a rallye downward in the next couple of weeks with slightly average to well above average losses.
But this is just a guess, not knowledge...

43
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 30, 2019, 08:25:28 PM »
NSIDC Total Area as at 29 January 2019 (5 day trailing average) 12,493,988  km2


         
Other Seas         
Okhotsk______    22    k   gain
St Lawrence___   -1    k   loss
Hudson Bay___    0    k   gain


If I look at the table, in the last two days only the increase in Okhotsk made up for the overall loss of all the other seas...

44
Antarctica / Re: Thwaites Glacier Discussion
« on: January 30, 2019, 07:00:20 PM »
New melting and breaking off at Thwaites Glacier. Today I analysed the outer ice field which continues Thwaites Ice tongue to the northwest. I compared the EOSDIS data from Jan 12 and Jan 30, 2019. I marked lost fast sea ice positions in pale magenta and newly formed cracks in orange. I wonder whether this outer ice field, which now has almost completely lost its connection to the Thwaites Ice tongue, will survive this fading austral summer.
See attached picture.

45
Antarctica / Re: PIG has calved
« on: January 28, 2019, 06:40:08 PM »
I hope I understand that correctly. The ice bergs in that region of course originate from PIG. But couldn't the "gaps" between them be already open sea, covered with (thinner) sea ice??

46
Antarctica / Re: Thwaites Glacier Discussion
« on: January 28, 2019, 06:37:41 PM »
In addition to the posting I have just made and in addition to my post from yesterday I have to report that a further new crack in the fast ice / ice mélange of Thwaites has developed yesterday.
See attached image.
Colour code: orange is the crack I have just mentioned, yellowish green is the crack I reported of yesterday and the new crack which connects both cracks is painted in pale magenta.
It seems that the whole thing is about to collapse.

47
Antarctica / Re: Thwaites Glacier Discussion
« on: January 28, 2019, 05:59:41 PM »
New big movement in the Thwaites fast ice / ice tongue / ice mélange (call it what you like). This time it goes further than any time this austral summer (orange line) and comes close to the calving front of Thwaites glacier (approx. 20-30 km). I also marked with a thin dotted yellowish green the position of the crack I posted yesterday (please note that Sentinel and EOSDIS use different orientations).
See attached image.

48
Antarctica / Re: PIG has calved
« on: January 28, 2019, 05:47:26 PM »
If I understand the orientation correctly, it's probably some ice rise. These glaciers are hard to wrap your head around.
Does the fact that there is an "ice rise" principally exclude the presence of frozen sea water with ice bergs in it above that ice rise? I am no glaciologist, so please excuse my question.

49
Antarctica / Re: Thwaites Glacier Discussion
« on: January 27, 2019, 09:14:32 PM »
There is a new big crack going through the fast ice of the Thwaites Ice Tongue that separates Thwaites glacier (to the south) and thicker ice originated from Thwaites Glacier (to the north). I checked Sentinel images from earlier January and late December and the crack was only very partially visible at that time. The crack goes through the thinner sea ice, not through any of the bergs.
I wonder whether the whole thong can separate due to currents and winds in the next days or weeks or whether the northern part will stay where it is because it is grounded in shallow waters. Any idea?
See attached figure, crack again indicated by yellowish green line (the thicker parts of it south of the crack so you can directly see it). The thicker the line, the wider the crack.

50
ASLR,

I just want to "join" Shared Humanity in saying that your contributions in this thread are very valuable and necessary. I thank you for your daily effort of informing us about the latest results of peer-reviewed science.

Stephan

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