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Messages - Stephan

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1
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.

2
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).

4
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.

5
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.

6
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:

7
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.

8
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).

9
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.

10
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...

11
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?

12
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...

13
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.

14
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.

15
Antarctica / Re: PIG has calved
« on: February 01, 2019, 07:36:47 PM »
No problem, you're welcome   :)

16
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.

17
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.

18
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.

19
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.

20
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.

21
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

22
Antarctica / Re: Thwaites Glacier Discussion
« on: January 25, 2019, 06:24:03 PM »
A new crack runs through the Thwaites Ice tongue (it can't be fast sea ice as it moves every day) and a big portion is about to break off (direction indicated by arrows).
From EOSDIS worldview Jan 25, 2019

23
Antarctica / Re: PIG has calved
« on: January 22, 2019, 08:01:39 PM »
A small part in the northeasternmost corner of the PIIS has calved these days. I circled the resulting iceberg and the corner where it broke off.
See attached picture.

24
Arctic sea ice / Re: "Stupid" Questions :o
« on: January 20, 2019, 10:26:49 PM »
If ppm of C02 are increasing in the atmosphere, that must mean ppm of something else is declining. What other atmospheric gas is declining as CO2 increases, and does this need for something else to decline at all effect the rate of growth of CO2 ppm in the atmosphere?

Carbon in fossil fuels are burned(oxidised) to create CO2, so it is O2 in atmosphere that is declining. The effect on O2 in the atmosphere is negligible:

CO2  280 ppm  -> 410ppm (46% change)
O2 209590ppm -> 209460ppm (0.06% change i.e. you experience more effect of less oxygen at top of small hill than at bottom)

Obviously this change in O2 hardly makes any difference to the ability to burn fossil fuels.

Edit ppm typos

If you take a typical hydrocarbon as a fossil fuel source you must also take the hydrogen atoms into account (octane taken as an example, the others look very similar):
C8H18 + 12.5 O2 → 8 CO2 + 9 H2O
This means that for every CO2 molecule you produce you lose a little more than 1.5 O2 molecules.
Of course some of the CO2 that is produced comes from black carbon (coal) where almost no hydrogen is present. So the ratio between CO2 gain and O2 loss may lie somewhere in-between 1.2 and 1.4. Nevertheless, the (slightly) increased O2 loss is negligible (as a fraction of existing oxygen in the atmosphere) compared to the relative strong increase of CO2.

26
Antarctica / Re: PIG has calved
« on: January 19, 2019, 08:56:22 PM »
Also at the NE edge of Pine Island Bay a massive disintegration of the fast ice occurred last week. See the new cracks (marked in red) and the little island (is that Pine Island?) at the bottom (marked in green), now freed from ice. Please be aware that these two pictures show the changes that happened last week (upper pic Jan 12, lower pic Jan 19)
Taken from EOSDIS worldview

27
Antarctica / Re: PIG has calved
« on: January 19, 2019, 08:38:22 PM »
A big change occured with the sea ice in front of PIIS within the last days. Please compare the two pictures from Jan 09 (above) and today (Jan 19, 2019), both taken from EOSDIS worldview.
It looks like a complete break-up and partial collapse of the sea ice, combined with a massive NW movement of the calved icebergs from Oct 2018 and the remains from the calving in 2017 (don't remember the month).
PIIS and the NW tributary fronts are now completely exposed to open water...

28
Antarctica / Re: What's new in Antarctica ?
« on: January 17, 2019, 07:52:09 PM »
"...But isn’t the big fear the Great Discontinuity, where a whole lot of ice areas begin similtaneous sudden collapse?  ..."

While it is of significant concern about how fast sea level might rise, the other big fear is that we start something that will continue for centuries and has a large net sea level increase.  Best estimates for Pliocene sea level, the last time CO2 was around 400 ppm,  are around 20 m higher than modern...
...which would cause probably one billion refugees who will look for another place to live and who can not be sent back to their original countries/areas because these will be then completely inundated.

29
Antarctica / Re: PIG has calved
« on: January 05, 2019, 07:42:36 PM »
I keep on watching the Amundsen Sector of Western Antarctica carefully. The last two days a large chunk of fast sea ice broke off in the Pine Island Bay. I have added a picture generated by the EOSDIS "Start Comparison" button. The right half was photographed on Nov 19, the left half is from today. Try this comparison option out by yourself!

30
It looks like the whole thing (ca. 20 km x 60 km) is breaking apart. I marked the "calving fronts" in red. It is not only sea ice, but in the "calving area" are also icebergs from the Smith/Kohler glaciers. New open water (marked in blue) has also appeared.
Picture taken from EOSDIS worldview Jan 01, 2019.

31
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 (??)

32
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 18, 2018, 06:47:34 PM »
I think we all should wait a couple of days until the measurements are (then hopefully) settled again.

33
Thank you for having you back. We have missed your contributions.

34
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.

35
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...

36
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.

37
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 10, 2018, 04:47:35 PM »
Just a question for us all.
We already have seas that melt out completely (like Hudson or Kara). Would these seas be an example for a BOE? And has anyone ever monitored the rates of volume, thickness and area decline close before the end and compared these rates with the rates at about 30, 50, 70 % of ice coverage? This analysis (also the relation of the rates) could help to answer the questions that arose in this thread.

38
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 04, 2018, 09:11:24 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. September value now includes 2018, and BOE seems to appear later than extrapolated last year, mostly due to a slight increase in volume 2018 compared to 2017.
See attached table.

39
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 04, 2018, 05:47:40 PM »
Ned W,
thank you for the re-analysis of data around the yearly minimum. It is an interesting plot and shows that the last two weeks are not so unusual as they appear to be.

40
Arctic sea ice / Re: Global sea ice area and extent data
« on: October 03, 2018, 10:22:05 PM »
Once again the pen draws a line on previously untouched areas of this graph.
The closest years in global SIE are 2017, 2016 and 2012. This is not by chance, but a trend.
I wonder whether SIE loss in the Antarctic will start soon (then we may see a global SIE like 2016) or whether it will be delayed (then the global curve should more look like 2017).

41
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: October 03, 2018, 09:54:33 AM »
Step by step 2018 SIE comes closer to the value of 2007...

42
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 23, 2018, 09:13:46 AM »
This is the third lowest on record, being behind 2012 (lowest) and 2007 (second lowest).
Compared to the two previous years Sep 22 2018 has 0.21 mio. km² less ice than Sep 22, 2017 and 0.12 mio. km² less ice than Sep 22, 2016.
The highest value of the 2010s on this date were 2013 (5.00) and 2014 (5.04 mio km²)

43
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 07, 2018, 05:07:33 PM »
It is time for the monthly update of the comparison of actual data with the long term trend.
August 2018 is 0,16 mio. km² below the long term linear trend, see attached graph.

44
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 07, 2018, 04:30:24 PM »
In my opinion, painting horizontal lines into the ice extent or volume data from 2007 to 2017 is cherry picking at its best. The same was done by AGW deniers with global temperatures, choosing 1998 as an extra warm year as start and drawing a line until 2013 (comparably cool), claiming the pause of global warming is the beginning of a forthcoming cooling. The T rise of 2015 and 2016 and 2017 has stopped them doing that.
It is the long term trend that is important. The natural variability which adds upon the decreasing trend has to be taken into account when interpreting or extrapolating the data.

45
Glaciers / Re: Alpine Glaciers
« on: August 24, 2018, 07:36:13 PM »
Here is a link to foto-webcam.eu of the Kleinfleißkees, Austria. You can switch from year to year from 2014 to 2018 to see the changes.
https://www.foto-webcam.eu/webcam/kleinfleisskees/2014/08/23/0900
The Goldbergkees, Austria is decreasing quite fast from 2016 to 2018:
https://www.foto-webcam.eu/webcam/goldbergkees/2016/08/23/0900.
The famous Pasterze is also melting. Use the year-to-year button to see it grow (backwards) or shrink (forward): https://www.foto-webcam.eu/webcam/freiwandeck/2018/08/24/0700

46
Thank you iwantatr for this animation. It is quite a big difference.

47
Thank you Espen for this impressive animation. Can you give us a rough scale of the size of the calved ice pack?

48
Arctic sea ice / Re: Latest PIOMAS update (August)
« on: August 06, 2018, 09:46:31 PM »
Thank you Juan for your work.
It clearly comes out that the major change in ASI happened in 2007. Since then only minor changes have occurred, expressed mainly in further reduction of volume, especially in OND due to later freezing / intrusion of warmth through the Atlantic side.

49
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 27, 2018, 03:37:22 PM »
OK, I've finished reprocessing all the monthly NSIDC ice concentration data, to see what the effect would be of changing from a 15% threshold for extent to a 30% threshold. 
[...]
Yes, exactly.  Switching to a 30% threshold would delete 0.72 million km2 of extent on average, so we'd hit the "ice-free Arctic" threshold very slightly earlier.  But it would be an artificial distinction.
Thanks for this work. It seems like the difference between 15% and 30% extent is season-depending as mostly five peaks appear in almost regular manner in every five-year period.

50
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 12, 2018, 06:51:49 PM »
The three most southern seas with significant ice are Baffin, Hudson, and Kara. I just compared their area (from Gerontocrat's actual post → THANK YOU FOR THIS VERY VALUABLE CONTRIBUTION!!) with their extent (from MASIE). All these seas show a very low compactness which makes them likely to melt out the next week(s):
Baffin area 0.23 extent 0.55 (compactness ~ 40%)
Hudson area 0.28 extent 0.70 (compactness ~ 25%)
Kara area 0.28 extent 0.50 (compactness ~ 55%)
The extents sum up to 1.75 mio. km² which should lead to further "century meltdowns" in the next days...

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