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Messages - nukefix

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1
Arctic Background / Re: Whose data is wrong?
« on: August 17, 2017, 05:15:27 PM »
(3) Heindric Ice Berg Armada (= Ice Debris Flows + Slip-Slide Ice Discharges + Hydrofracturing of North Greenland Ice Sheet on land + Rapid Erosion Forces + Perimeter and Continental Slope Failures), producing the job finished:
This is 100% a glaciological prediction - can you find peer reviewed publications by glaciologists predicting this mode of ice-sheet failure in Greenland? I've spent quite a bit of time talking about the Greenland ice sheet with professional glaciologists and I don't recall it ever been mentioned. References please.
Hey VAK care to comment on the above? Have you invented a new failure-mode for the Greenland ice sheet or is this already known in the glaciological community?

2
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: August 16, 2017, 11:23:50 AM »
Amazing blue iceberg spotted in Jakobshaven icefjord:

http://apps.sentinel-hub.com/sentinel-playground/?lat=69.16542768047643&lng=-49.78935241699219&zoom=12&preset=1_NATURAL_COL0R&layers=B02,B08,B12&maxcc=100&gain=0.4&gamma=1.0&time=2015-01-01|2017-08-10&cloudCorrection=none&atmFilter=ATMCOR&showDates=true&evalscript=

3
Arctic Background / Re: Whose data is wrong?
« on: August 13, 2017, 11:10:14 AM »
(3) Heindric Ice Berg Armada (= Ice Debris Flows + Slip-Slide Ice Discharges + Hydrofracturing of North Greenland Ice Sheet on land + Rapid Erosion Forces + Perimeter and Continental Slope Failures), producing the job finished:
This is 100% a glaciological prediction - can you find peer reviewed publications by glaciologists predicting this mode of ice-sheet failure in Greenland? I've spent quite a bit of time talking about the Greenland ice sheet with professional glaciologists and I don't recall it ever been mentioned. References please.

4
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: August 11, 2017, 11:41:04 AM »
A beautiful Sentinel-1 track crossed Greenland yesterday...while sightseeing I managed to spot both the Greenland summit site and the NEGIS coring site on the imagery. Images downloaded from PolarView.

5
Greenland and Arctic Circle / Re: Greenland 2017 melt season
« on: August 11, 2017, 10:10:04 AM »
It's devastating for the local wildlife. Tundra grows very slowly.
I would think it's a normal part of nature there.

6
Arctic sea ice / Re: The 2017 melting season
« on: August 10, 2017, 10:54:47 AM »
Here's the cloud coverage situation on Friday at 1200UTC.

That's one I don't think I've seen before. Gotta link?
That's from ECMWF directly so it's not freely available...(a pity).

7
Arctic sea ice / Re: The 2017 melting season
« on: August 10, 2017, 10:11:55 AM »
"...to finish the job?"
Misconception. I disagree! The job isn't "finished" at that point, but only at its very beginning! The ocean melting advances and its re-freeze delays further. This exposes the ocean to sunlight much closer to the solstice and then staying exposed to that sunlight for longer.
But it looks like none of the sunlight is hitting the surface directly due to extensive coverage of low clouds this summer. This could be a feedback resulting from more open water that is preserving the ice.

edit: here's the cloud coverage situation on Friday at 1200UTC. Sun can only hit the surface full on in white areas & the colours depict low/medium/high cloudiness situation.

8
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 09, 2017, 10:32:06 AM »
It's not cloud. The ridge can be seen in the ice on this Aug 4th image from WorldView. Could it be bands of thicker ice formed originally by ridging that are now moving? Similar patterns also appear in the areas that are melting out inside the ice perimeter.
My guess is it's a shadow of a contrail. I saw one crossing southern Greenland from an airplane and it really looked odd before I understood what it was..

9
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 07, 2017, 07:19:00 AM »
"When will AGW accelerate the loss ?"
When the meltwater of the interior gets access to the ocean?
Indeed. Or when Zachariae Isstrom decides to let all hell break loose.
According to Bedmap2 there's only limited scope for retreat at NEGIS.

10
Greenland and Arctic Circle / Re: Greenland 2017 melt season
« on: August 04, 2017, 04:52:57 PM »
The fire looks great in S-2 SWIR-combination:

http://apps.sentinel-hub.com/sentinel-playground/?lat=67.84888987414084&lng=-51.514892578125&zoom=12&preset=91_SWIR&layers=B8A,B03,B02&maxcc=100&gain=1.0&gamma=1.0&time=2015-01-01|2017-08-03&cloudCorrection=none&atmFilter=&showDates=false&evalscript=

It could burn until the next rain I guess..

11
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 04, 2017, 03:46:16 PM »
NASA GRACE analysis from 2002 shows almost linear Greenland Ice Sheet mass loss trend. When will AGW accelerate the loss ?
Arguably this already happened in the 1990's...but yes melting can potentially increase by a lot and we could have more summers with 2012-like extreme melt...

12
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 04, 2017, 11:56:42 AM »
Ice sheets that are grounded on an inward-sloping submarine bed are fundamentally unstable, for example WAIS. In Greenland this is not expected to happen as the topography of the bedrock is much more benign:

https://www.the-cryosphere.net/7/499/2013/tc-7-499-2013.pdf

Jakobshaven goes deep inland under present day sea level but it's narrow. Mean-image of S-1 over 2017 brings the movement out nicely..

ps. I'm not familiar with the acronym GDF?


13
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 03, 2017, 04:14:27 PM »
Here's the mean backscatter of a large stack of Sentinel-1 HH SAR images taken this year. There's are several ice-streams in the picture but no rifts..

14
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 03, 2017, 11:48:01 AM »
I re-enclose the rift image a year ago 24.07.2016. If you had read my paper with care, you should have seen this link to the original NASA image (ref: endnote No. 40).
I don't see a "rift", only some topography-related differences in brightness. They could be related to bedrock-topography but I don't see anything out of the ordinary. I'm also checking a stack of Sentinel-1 radar images via Google Earth Engine and everything looks fully normal.

15
Greenland and Arctic Circle / Re: Greenland ice sheet retreat
« on: August 02, 2017, 04:56:33 PM »

As I commented elsewhere the slope of Greenland margin is small and not conducive to rapid runaway collapse than can happen on much steeper mountain glaciers.

ps. can you share the location of the NEGIS-crevasse you mention, it would be interesting to track it with Sentinel-1?

16
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 02, 2017, 03:07:09 PM »
By mid-September much of ice could be so thin and disperced that satelites won't notice it

SAR will still see it, unless it's possibly some kind of slush, but I don't think that is a stable configuration for the ice (?).

http://www.polarview.aq/arctic

17
Arctic sea ice / Re: The 2017 melting season
« on: August 02, 2017, 03:02:31 PM »
The low-lying north Greenland ice sheet builds water within its ice and beneath it most rapidly until the whole flat-lying ice sheet collapses due to (the newly discovered) process "Glacier Debris Flow" (GDF):  Meyer, Robinson: "When Glaciers Transform Into Deadly 150-mph Avalanches - After happening only once in the 100-year record, catastrophic glacial collapse occurred twice in Tibet this summer", The Atlantic | Science, 18 October 2016.
That is needless "alarmism". The slope of the Greenland ice sheet is just a few degrees close to the coast (+it's a lot flatter everywhere else) - this very effectively prevents it from turning into a 150-mph avalanche!

18
Interesting that it all moves in concert, suggests to me that it's driven by escaping melt water, not that tide action can altogether be ruled out.
I think that's rather standard with a calving, it looks like the new calved iceberg pushes everything away and ice-melange & sea-ice transfer that impulse quite far.

19
Greenland and Arctic Circle / Re: Greenland 2017 melt season
« on: July 25, 2017, 05:22:23 PM »
Also the contrast of 2017 with 2012 is spectacular. It has always added to my conviction that 2017 was not going to see a massive sea ice melt.
My thinking is that there's a limited amount of extra heat around - if Greenland is super-warm some other area is therefore cooler and sometimes this can conserve sea-ice. So let's see...

20
Greenland and Arctic Circle / Re: Greenland 2017 melt season
« on: July 22, 2017, 12:04:58 PM »
The Greenland surface melt products are sensitive to the presence of small amounts of liquid water (wet snow) on the surface. The SMB can still be positive when surface melt (=wet snow) is detected on the ice sheet.

21
Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 12:23:14 PM »
Whats been driving me quite bananas over the last few week is how rare it seems to be to get anything but a few tiny gaps in the clouds to see what the ice really looks like.

Luckily we'll always have radar ;)

http://www.polarview.aq/arctic



22
Arctic sea ice / Re: The 2017 melting season
« on: June 29, 2017, 10:28:15 AM »
I found this sea-ice portal by the Alfred Wegener Institute and University of Bremen...should be added to the resources I think:

http://www.meereisportal.de/en/

23
Wonderful clear skies on the 26th Jakobshavn retreats on all fronts if you have the time take a look round.
Wonderful image...the shadow of the main branch looks like it will allow the estimation of the calving front height via using incidence angle & sun elevation angle at the time of imaging...

24
There's no way a 4.0 earthquake can start a tsunami. It might trigger a landslide or huge calving though. I'd look through satellite imagery including Sentinel-1 and try to identify what has changed.

25
Petermann "wakes up" in July, at least in the past two years. Image source: Enveo Cryoportal

26
Arctic sea ice / Re: The 2017 melting season
« on: May 29, 2017, 04:25:45 PM »
The probabilistic extent 50 days from now is in freefall..:

http://cires1.colorado.edu/~aslater/SEAICE/

27
Antarctica / Re: PIG has calved
« on: May 07, 2017, 05:02:28 PM »
The pixel noise in these Sentinel radar images make it hard to be sure. But it looks as some more opening/deepening at the ends of the crack.
Yes, if there's coherence InSAR would be the way to see the progress for sure.

28
Policy and solutions / Re: Becoming Vegan.
« on: May 04, 2017, 12:45:35 AM »
Most people most of the time through most of history (at least since the Agricultural Revolution) have been mostly vegan.
AFAIK that is total bullshit. There are no vegan indigenous people, not even a single culture.

29
The rest / Re: Real Stupid Blog-Posts
« on: April 29, 2017, 05:17:54 PM »
It just funny that someone attacks the argument "The arctic could be virtually ice free in a couple of summers" on the basis that it hasn't happened yet. The argument is true and there are high odds for yet another record low this summer...

30
The fjord is always pretty full of icebergs and they also flush out.

31
Arctic sea ice / Re: The 2017 melting season
« on: April 29, 2017, 12:28:41 PM »
The ice around Newfoundland is almost certainly the result of collapsing glaciers not sea ice. Its one area where an increase in 'sea ice' can be expected as glacier collapse in Greenland becomes more prevalent.
Why would glacier mass-loss cause that? Something to do with the extra meltwater?

32
The rest / Real Stupid Blog-Posts
« on: April 27, 2017, 02:43:03 PM »
This is a very, very dumb video from the denialist-fringe:

https://realclimatescience.com/2017/04/new-video-can-we-trust-climate-scientists/

Let's see what he says after the next record low.. :o

33
Interesting, does the AMO-reconstruction show the abrupt end of the LIA, or something else?

34
Arctic sea ice / Re: The 2017 melting season
« on: April 19, 2017, 08:32:28 PM »
Neven,

Yes, therefor i use the finnish service for Snowmass, because they cutting out mountain sides: http://www.globsnow.info/swe/GCW/


AFAIK the Globsnow algorithm is the best-in-business currently.

35

Eh...hmmm... what "physical" "stuff"?????

There a lot of variables you can use as a proxie for surface melting, ocean melting and so on, means fitting on physical base
I suppose one could run 500 instances of climate models for the next 50 years and use each of those runs to force PIOMAS. But the ocean currents would still be out of whack I guess. This shit is hard.

36
Satellites are expensive. Modelturbation is cheap.
All models are wrong, but some are useful. Meanwhile satellites...are needed to constrain the models. And even with well constrained models extrapolations into the future are problematic.

37
Spectacular imagery! BTW SNAP-toolbox can be used to track glacier-speed but I think the parameters take some experimenting.

38
Arctic sea ice / Re: Choosing a Base to compare ASI lost on PIOMAS Volume
« on: January 05, 2017, 11:39:28 AM »
I voted other and would prefer:

30-year period 1979-2008

39
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: January 05, 2017, 11:33:01 AM »
I'd like to see a version where zero is included in the y-axis..

40
I'm not sure this really belongs here but given our discussions on monitoring glacier speed using image tracking this seems appropriate.
ESA SNAP toolbox does image tracking, it works at least for SAR images and perhaps also with optical.

41
Arctic sea ice / Re: The 2016/2017 freezing season
« on: November 25, 2016, 11:35:09 AM »
If CryoSat's observations are wrong (and note the observation lag) then ESA has wasted hundreds of millions of euros.

Even if they were "wrong" over sea ice (and they aren't), CryoSat is still totally invaluable for making ice sheet observations.

42
Greenland and Arctic Circle / Re: Piteraq - The Greenland katabatic wind
« on: November 21, 2016, 10:14:46 PM »
Yes had the chance to try it in a spa in Finland...would like to do it again :)

43
Greenland and Arctic Circle / Re: Piteraq - The Greenland katabatic wind
« on: November 17, 2016, 03:22:17 PM »
Interestingly "wind chill" calculators equate that situation with about -25C with no wind, which must be totally incorrect! The catabatic wind in question would kill a naked person extremely quickly, while hanging around in -25C with no wind at all is not that dangerous (I've spent 3 minutes in -110C with no real problems at all).

44
Arctic sea ice / Re: IJIS
« on: November 02, 2016, 06:20:23 PM »
Yes, but ICESat-2 will be using laser instead of radar. And radar is not good with open saline waters.
I'm not aware of problems with using radar-altimetry over ocean (saline), but I know that meltponds cannot be distinguished from leads in radar altimetry data. Can a laser-altimeter differentiate between meltponds and open sea I wonder? 

45
Arctic sea ice / Re: IJIS
« on: November 02, 2016, 10:07:09 AM »
IceSat-2 requires clear-sky conditions to measure anything...hopefully a CryoSat-2 follow-on can be funded too..

ICESat-2 shall provide monthly surface elevation products to enable, when sea surface height references (leads) are available and under clear sky conditions, the determination of sea-ice freeboard to an uncertainty of less than or equal to 3 cm along 25-km segments for the Arctic and Southern Oceans

46
Arctic sea ice / Re: Gambling on The Ice
« on: October 25, 2016, 12:31:26 PM »
A bet that coffee will go up one day is a bet on bad crop-yields happening sometime in the future. It's not necessary to use futures to profit from this, there are ETF/ETN-instruments that are linked to the price of coffee, for example COFF or JO.

ps. I agree this is off-topic in this forum, perhaps admins could move this thread to the "Walking the walk"-forum?
Just for the the record, JO is up 10% from mid-June and around 30% since the bottom in the beginning of this year.

47
Hey A-team you are way better with animations than I am so here's the raw material.

ps. All hail S-1A/B!!
pps. The funky large waves are the cause of this...but what is causing the waves?
ppps. Looks like something introduced small shifts between the frames...in any case they should align perfectly if the small integer pixel shift is corrected

48
It looks like it happened between the 7th and 8th.
Yes, 2/3 of the Southern branch has calved between 06.10 & 12.10...I'm waiting for Scihub to get back online in order to download the S-1B scene acquired on the 18th. Meanwhile here's a lower-quality snapshot downloaded from polarview.

49
S-1A&B will be imaging the entire (almost) Greenland coast every six days...incredible! So many new things to be discovered in that data..

Year-round velocity monitoring of every outlet glacier with calving front locations suddenly possible. Optical will never be able to do this...

50
I believe the "wedge" is still attached, see this lower resolution S-1A from 5.10 (the corresponding GeoTIFF would clearer as no land-mask has been applied):

http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SDH_20161005T205513_E454_N_1.final.jpg

..the big wavelike structures on the north edge of the southern branch are curious, I wonder if they are caused by thinning, increased flux from the north edge or something else..


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