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Author Topic: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland  (Read 1086000 times)

A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1150 on: December 16, 2015, 01:25:45 PM »
Below the oblique eastward-looking airplane window shot of Jakobshavn from 21 Oct 15 has been enlarged (first image) more than it really supported and then annotated (second image)  for some of the features that would not be so evident from either Landsat or Sentinel.

The 3rd image is from the nearest Landsat band 8 to this date, 10 Oct 15, and the 4th uses perspective view to better approximate the airplane image. Both are rotated 90º CCW.

It might be worth passing the hat to pay for this to be done right in early March from a chartered plane out of Illulisat since the scientific community is never going to get around to it (conflicts with published models). At Denali, all the oblique photography was done by hanging-out-the-cargo -bay 9"x9" hand-held camera with film (which digitizes to 4200 dpi). The image below is just a smartphone shot through a plexiglass window, though at a better elevation than helicopter views.

A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1151 on: December 16, 2015, 01:48:37 PM »
Just adding the bracketing Landsat of November 4th, the latest of the year and quite a clear shot. The sun angle here was 5.0º which is more favorable for topographic detail than the 13.7º of the somewhat cloudy October 10th Landsat above. There's a lot of excellent detail in the Nov 4th but it's still hard to understand the local topography without an accompanying oblique.

In theory, the Landsat could be draped on a DEM and displayed as hill-shaded from any perspective. That would require a contemporaneous DEM determination to make any sense. We don't have any sense how stable the fine scale topography is over the summer months. That will change with Sentinel 1B. Click for full size.

Espen

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1152 on: December 18, 2015, 09:30:32 PM »
As reported earlier by A-Team a large calving (or a new one) is underway:
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Espen

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1153 on: January 10, 2016, 12:53:42 AM »
A calving tsunami:

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Espen

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1154 on: January 10, 2016, 12:57:23 AM »
And the Cathedral of Jakobshavn torn down in a minute:

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sidd

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1155 on: January 10, 2016, 06:04:51 AM »
thanx. awesome.

A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1156 on: January 10, 2016, 09:49:36 PM »
The really scary part is not the wave from the iceberg rolling but the comment sections -- the level of ignorance, the laziness of no fact check(they're already online, typing), the overwhelming volume of nasty teenage boys, and the appalling illiteracy and bieber-like rudeness that could never be used face-to-face. We're saving the planet for these jerks?

Meanwhile, something like 5% of the speakers have shared their slides from AGU2015 public talk (not AGU-videoed; smart phones not allowed in lecture rooms). Once again, the AGU arranged the website with an eye to hiding talks with posters --  to find them, you have to click through myriad sessions to the abstract level, script a crawler, or offshore it to India (like academics do with final exam grading).

Even if you went to the meeting, you could very well have been at a competing session or out in the hall talking. Researchers are torn between desire to bag a ResearchGate entry and fear competitors will eat their lunch (but that's half the people in the room!).

Meanwhile, meeting fees, hotel, meals, plane, booze, lyft, research, salary, medical, retirement -- every penny of the speakers' lifestyle is funded by the public, those Little People who can wait 6-18 months for an eventual $39 paywalled article.

Is this the best way to move climate science forward, a roomful at a time; is there time left to play these games?

We haven't said boo on these forums about the two imaging alternatives to ice penetrating radar, namely air gravity and seismic. It's harder to engage with these data because processing is done within big black boxes of proprietary software.

The work below was done in Vista (donated by Schlumberger) and Kingdom (donated by IHS). Shell could have some leftover Arctic workstations with these installed but I can't really envision them offered to Neven. Besides, nobody releases raw seismic data, though Icebridge airgrav data is online and we'll see a ton more of that with O.M.G.

Jakobshavn turns out to be inconveniently complicated -- the ice never touches bedrock. There are hundreds of meters of basal till, lapping facies of accreted sediment, re-worked sediments in various states of hydration and plain water. This result seems a total disconnect with their 2008 analysis of this very same seismic line.

According to seismic, NEEM mistakenly stopped drilling at the first encounter with 50-100 m of till lying on bedrock. NEEM was drilled at the worst site imaginable but the new narrative sees this as a wonderful opportunity. The entire rig has been dragged off to a site on NEGIS which one hopes was thoroughly studied beforehand.

Quote
C11C-0768
Seismic Imaging of Sub-Glacial Sediments at Jakobshavn and NEEM
Georgios Tsoflias et al [seismic geologist at U Kansas]

We used active source seismic reflections [half-kilo PETN explosives at 10 m depth] to image sub-glacial sections at Jakobshavn and NEEM. Processes at the bed, especially in areas where deformable layers are present, can dominate ice stream flow. Ice stream behavior is different over deforming till than over a water-lubricated ice/bed interface.

Seismic waves like radar have the capability to penetrate below the ice but unlike radar can differentiate sub-glacier till and basal water from bedrock via reflection amplitude and polarity. (The speed of sound in ice is ~3745 m/s but 3600 m/s in sub-glacial sediment and 5800 m/s in Jakobshavn bedrock.)

Previous seismic studies focused on determining ice-column properties. We didn't do any new work at Jakobshavn but instead re-processed an older 9.8 km seismic profile taken by Horgan in 2008 about 100 km east of the terminus.

At a site 6.5 km north of NEEM, we acquired a long-offset  [ie between seismic source and reflection receiver], pseudo-CMP [Common-Mid-Point]seismic gather [reads (traces) collected by set of receivers; reflection from a flat interface produces a curved series of arrivals on the seismic traces since it takes longer to travel to the far offsets than  near offsets].
 

Quote
HJ Horgan, S Anandakrishnan,  RB Alley, LE Peters, GP Tsoflias, DE. Voigt, JP Winberry (2008), Complex fabric development revealed by englacial seismic reflectivity: Jakobshavn Isbræ
http://onlinelibrary.wiley.com/doi/10.1029/2008GL033712/pdf free full

We argue that the reflectivity results from successive changes in crystal orientation fabric. In turn, these contrasting fabrics are thought to result from contrasts in impurity loading and subsequent differing responses to strain. A prominent reflector corresponds to impure Younger Dryas aged ice, and the discontinuous and chaotic reflectors near the base correspond to LGM to Stage-3 ice, where enhanced deformation is occurring. These results have particular importance for studies of fabric development and predictive ice sheet modelling.
« Last Edit: January 10, 2016, 10:02:53 PM by A-Team »

sidd

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1157 on: January 11, 2016, 05:58:00 AM »
Re: saving the planet for these jerks?

As for myself, yes, I am saving the planet for these jerks. After all, I have been a jerk in my life, i have been evil in more or less degree on occasion, and no doubt, will again. I envy those who are fortunate enuf to claim the contrary. If I do not act to "save these jerks" then why should anyone save me when, as is inevitable, i need saving ?

To parafrase Hillel: If not us, who ? If not now, when ?

sidd

A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1158 on: January 11, 2016, 04:06:17 PM »
Quote
"save these jerks"
I see quite a contrast between the US response to Sputnik (double-down on science and engineering) and the response to catastrophic climate change (double-down on paid trolls, vandalize public discourse, spew media disinformation, interfere with political process). It's not going to work: nature bats last.

It's been a while since we've looked at JI on Sentinel. The Jakobshavn Isbrae winter images below are from 10 Jan 16 (s1a-iw-grd-hh-20160110t204703-20160110t204728-009437-00dad1-001.tiff) which comes to you pitch black and upside-down. It cleans up quite a bit if you just hit it in ImageJ with Process --> Enhance Contrast... --> Normalize + Equalize followed by vertical flip and screenshots at increasing levels of resolution.

I was not expecting the calving front to still be so far east. We haven't had much access to winter scenes from previous years so it's hard to say how anomalous this is or whether it portends record retreat once things warm up again.

I noticed the other day that Google Image search is starting to pick up our forum images. In fact it can get downright embarrassing -- like 18 out of the first 20 for a well-chosen phrase on Petermann. In any event, I am taking more care now to provide more informative (verbose) file names to help it find us and to spell things out more in the text to bring in the traffic that the overall site deserves.
« Last Edit: January 11, 2016, 04:18:49 PM by A-Team »

nukefix

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1159 on: January 13, 2016, 02:08:41 PM »
I have a feeling we're close to a wintertime record retreat...this could be checked by comparing against historical digitized calving front positions.

Espen

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1160 on: January 13, 2016, 06:29:31 PM »
A-Team: "I was not expecting the calving front to still be so far east. We haven't had much access to winter scenes from previous years so it's hard to say how anomalous this is or whether it portends record retreat once things warm up again."


Yes, the calving front is further east this winter it seems, but I rather wait to the Landsat season begins before saying something wise?

Using text when publishing images, was always a clever thing to do even back in the old days when Alta Vista was the king of search engines.

And it is interesting to watch all the outlet glaciers all around the "island" are "steaming" ahead. Hard glacier contrails *) are seen all over the places. *) Ice is "Hard Water" in Thai : Nahm Kheng

But be aware when searching on Google Image, loads of irrelevant stuff shows up ?:
« Last Edit: January 13, 2016, 07:32:23 PM by Espen »
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Laurent

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1161 on: January 13, 2016, 07:22:46 PM »
I don't have a reputation to maintain so may I say I think the glacier was on a sill (good word?) and now it is retreating faster until the next one.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1162 on: January 13, 2016, 10:21:20 PM »
i don't have a reputation either so I will go out on a limb and say the glacier will have retreated to the bend by the end of next melt season.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1163 on: January 13, 2016, 11:02:03 PM »
A 2016 breakthrough in Greenland's Zachariae Glacier (Gletcher) and Nioghalvfjerdsfjorden (79N) contributions to catastrophic sea level rise and Atlantic Meridional Overturning Current (AMOC) disruption may result from drilling midway up the North East Greenland Ice Stream (NEGIS) using the NEEM dome.

Far more likely Google image search will find many specialized climate change keywords here and the disproportionately large format calving glacier enthusiast picture in crawling this Arctic Sea Ice forum post and give them far higher search scores than they deserve. In fact, I expect this particular cryosphere post to get more visits than all my previous climate change articles combined, even though it is completely Greenland glacier and climate change keyword blather.

Quote
predict Jakobshavn glacier calving front will retreat to the bend by the end of the 2016 melt season.
That would take the calving front of Greenland's  Jakobshavn Isbrae glacier into unchartered warming ocean waters, in terms of reduced buttressing from channel elbow's 76º turn and meltwater and moulin effects. Whether it will lead to greening up and a pleasant climate for people and wildlife as in the Viking settlement days is implausible short term and we can do better than the second image in illustrating a potential new glacier retreat maximum.

The best internet resource on Zachariae Glacier is at this link; for Jakobshavn Isbrae the recommended link is below that.

http://forum.arctic-sea-ice.net/index.php/topic,400.550.html Zachariae articles
http://forum.arctic-sea-ice.net/index.php/topic,154.1150.html Jakobshavn glacier happenings
http://neven1.typepad.com/ overview of Arctic sea ice, cryosphere and climate change.
« Last Edit: January 14, 2016, 12:11:09 PM by A-Team »

Laurent

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1164 on: January 14, 2016, 12:13:01 PM »
It may already be in the next sill ... ?
That is something some of you posted. Will it move to the next one quicker ? (The bend like Shared humanity said)
let's see...


A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1165 on: January 14, 2016, 01:51:32 PM »
I'm looking at the final December 2015 AGU site with search term 'Jakobshavn' to see (1) which abstracts now have substantive eposter pdfs and (2) which make testable predictions of future glacier behavior.

It's not realistic to expect anyone to have foreseen the current anomalous winter calving line retreat but it's imperative that near-term predictive models display annual horizontal isochrons -- that is, lines drawn over a 2015 ice stream Landsat demarcating upstream ice that will calve off in 2016, 2017, ... 2026, ... 2036, ...2046, etc. (We've never see this to date in a Jakobshavn model paper because the whole point in daisy world modelling is to AVOID making testable predictions.)

Of the 16 talks mentioning Jakobshavn, one author put up an ePoster (see #1158), another uploaded slides to a campus home page and included a QR code to an animation (link now dead), and a third shared an illustrative diagram (crevasses, 3rd link), a fourth covers it on a personal research blog, and the 6th posted the whole thing -- slides and talk -- as a youtube. The other 11 speakers prepared and used a set of powerpoints but chose not to share anything with scientists who could not attend.

Scientists sometimes pretend that posting slides from a talk jeopardizes future journal publication. That is complete rubbish. Journals like Nature explicitly state on their submissions page that meeting talks and their ppts DO NOT constitute prior publication.

I had corresponded with one author of a Jakobshavn abstract that especially interested me. At that time "more work was ongoing, results were still in flux" and apparently they still are despite giving the talk and showing the slides, there's not been any followup.

I also searched with 'twitter jakobshavn'. Sometimes the poster or social media friends will know where links and photos are posted. This proved a substantial waste of time, either people brown-nosing colleagues or excitedly becoming aware of some dated news.

Another common practice (in the art of not giving anything away to 'competitors') is talk about something that you've already published. So I googled all the abstract titles giving partial credit to those indicating cooperative intent (listing conf papers on their ResearchGate page, 1 person) but negative credit to those merely repeating an old undocumented talk from "Illulisat Climate Days 2015 (1 person).

The cryosphere discussion journals did not show anything beyond what google search could locate. However it did turn up an available publication-in-review from Oct that was varied slightly in a Dec AGU2015 talk about Store Glacier, fair enough.

The very best at research are often the very best at sharing. That's not a coincidence either: if you do good work there's nothing to hide, whereas with shoddy work a fast-paced talk with lots of colorful ppts won't be fully assimilated; later peer reviewers in a closed-source journal can tell you all the things wrong with it and you can re-submit to another (paywalled) journal.

To summarize, glaciology has more jerks per square km than just about any other field of science. Every talk should be immediately and permanently available on youTube, no excuses. Every paper should be a ResearchGate download, no excuses.

https://agu.confex.com/agu/fm15/meetingapp.cgi/SearchResults/
http://www.pism-docs.org/wiki/lib/exe/fetch.php?media=applications:aschwanden_agu_2015.pdf (27 MB file, worthwhile)
https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/59874
http://www.nature.com/nature/journal/v528/n7582/full/nature16183.html (closely related Dec 2015 publication)
http://onlinelibrary.wiley.com/doi/10.1002/2015RG000504/abstract  (closely related Jan 2016 publication)
http://williamcolgan.net/blog/ (substantive researcher blog with closely related)
(41 minute youTube of E Rignot giving featured AGU lecture)
http://www.the-cryosphere-discuss.net/tc-2015-172/ ISSM modelling of Jakobshavn discussion paper
« Last Edit: January 14, 2016, 04:08:47 PM by A-Team »

sedziobs

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1166 on: January 14, 2016, 07:37:03 PM »
I see quite a contrast between the US response to Sputnik (double-down on science and engineering) and the response to catastrophic climate change (double-down on paid trolls, vandalize public discourse, spew media disinformation, interfere with political process).

I think Barack Obama may have been inspired by A-Team when writing his State of the Union speech this week:
Quote
Sixty years ago, when the Russians beat us into space, we didn't deny Sputnik was up there. We didn't argue about the science, or shrink our research and development budget.

A-Team

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1167 on: January 16, 2016, 11:01:03 AM »
Quote
nukefix in #1161: we're close to a wintertime record retreat...this could be checked by comparing against historical digitized calving front positions.
ESA has made an interesting effort in providing just that, in the form of a single massive kmz file that displays in your local copy of Google Earth (free, recommended). This shows surface elevation, ice velocity, calving front locations, etc for various years for a great many Greenland glaciers including Jakobshavn, Zachariae, Petermann and many others.

It's an ambitious project that is off to quite a good start. Using GoogE as the GIS display of overlays makes sense since nearly everyone is familiar with google's map style already. It will also animate items like Jakobshavn calving front by year though the controller is fairly lame.

What use are all these calving front lines? The main application seems to be communicating climate change (glacial retreat) to the general public via the dramatic if erratic trending retreat of Jakobshavn. Scientifically there is ice volume discharged, seasonal behavior, acceleration, correlation with bedrock sill and so forth.

This could get interesting going forward in 2016 especially using the regularity of Sentinel overflights. Here it might be better if the 'calving front' could located by a consistent robotic method rather than subjectively hand-picked. It's easier and quite feasible to stay within the raster world (rectangular pixel arrays, images) rather than digitize into the complications of vector.

I carved out the much smaller Jakobshavn kml file and attached it below for the convenience of people who just want to load up the digitized calving fronts from 2003-14 (1st image below). Unfortunately they didn't include 2011-13 or 2015.

Our forum-ware allows .txt attachments but not .kml so you will have to edit that file type back in after downloading. Double-clicking on the kml on your desktop then loads it into Google Earth as a temporary folder.

The kml files are human-readable in any text editor and worth glancing at to see how they are structured. Someone here could easily add the missing years by taking the 2014 as template and making edits to the calving front coordinates which could be taken off Landsats of various dates.

<LineString>
            <altitudeMode>relativeToGround</altitudeMode>
            <coordinates>
               -49.78702767799163,69.14088760638748,0 -49.78717188112478,69.14150124736989,0

The ice penetrating radar files are also provided by Cresis in this same format so those can be added to the mix. It's also feasible to tie in the actual radargram jpgs. However at some point you will be overloading GoogE to the point of slow to no responsiveness.

Quote
Data Products Visualisation Available
Submitted by Dag Evensberget on Wed, 2015-05-27 19:02
Printer-friendly versionSend by email

ESTECA visualisation of the Greelland_Ice_Sheets_cci data products has been made in Google Earth and is available for download (http://tinyurl.com/zvzuflg caution 13.1 MB kmz). In the visualisation, Surface Elevation Change (SEC) data and Ice Velocity (IV) data are shown as partly transparent overlays. Calving Front Location (CFL) data is show as polygons. The user may navigate and zoom using the relatively familiar Google Earth interface. The Google Earth program must be installed to view the file.

The temporal span of the data is controlled by using the time interval picker in the top left corner. The CFL data for various epochs may be inspected by setting the temporal span. The same may be done for the 5-year running means in SEC. For IV, the PALSAR partial coverage and the Jakobshavn and Upernavik focus areas comprise multiple snapshots in time. 

The color scale information is given as screen overlays. IV color scales are in the bottom left screen corner, while SEC color scales are in the bottom right corner.

Individual data products, individual elements of time series data, and the color scale information may be enabled and disabled in the Places tree (normally on the left).

http://www.esa-icesheets-greenland-cci.org/?q=node/158
« Last Edit: January 16, 2016, 11:17:08 AM by A-Team »

Shared Humanity

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1168 on: January 16, 2016, 05:41:39 PM »
Downloaded the image of the calving front locations and blew it up in order to better read the dates on the left. It is a real shame that crucial years are missing but it sure looks like the cork popped off that champagne bottle around 2009.

TenneyNaumer

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1169 on: January 17, 2016, 06:04:48 PM »
There has been a large outflow of meltwater into Disko Bay and Uummannaq.  I alerted Mauri Pelto, Alun Hubbard and Jason Box during the wee hours this morning.  They're having a look at it, and Mauri has already done a very nice blog post here:

http://blogs.agu.org/fromaglaciersperspective/2016/01/17/what-is-up-in-disko-ummanaq-bay-greenland-this-week/

What would be interesting now would be to see any topographic changes upstream near the calving front. 

AbruptSLR

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1170 on: January 17, 2016, 06:56:26 PM »
There has been a large outflow of meltwater into Disko Bay and Uummannaq.  I alerted Mauri Pelto, Alun Hubbard and Jason Box during the wee hours this morning.  They're having a look at it, and Mauri has already done a very nice blog post here:

http://blogs.agu.org/fromaglaciersperspective/2016/01/17/what-is-up-in-disko-ummanaq-bay-greenland-this-week/

What would be interesting now would be to see any topographic changes upstream near the calving front.

Tenney,

Great catch!

The first three images show the Nullschool Surface Wind and Temperature Maps for Jan 12, 14 and 15, 2016, respectively.  Showing that the formation of Hurricane Alex may have driven warm surface winds off the coast of Disko Bay.  The fourth Earth Ocean Current & SSTA Map for Jan 15 2016, shows that ocean currents (possibly associated with wind patterns) drove plenty of warm water off the coast of Disko Bay, which may have drive warm water into the fjord, which may (or may not) have triggered a calving event for Jakobshavn Glacier.

Best,
ASLR
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1171 on: January 17, 2016, 07:11:22 PM »
Also, relevant to Tenney's observation, my Replies 958 & 964 discuss the West Greenland Current's interaction with Disko Bay and calving events.

Furthermore, my Reply 966 and the following link show that from Jan 10 to 13 2016 there was a 2.8m tide at Ilulissat Isfjord:

http://www.dmi.dk/fileadmin/user_upload/vandstand_txt_pdf/2016/Ilulissat2016.pdf
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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TenneyNaumer

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1172 on: January 17, 2016, 07:22:25 PM »
Yes, it appears the event was sometime around Jan. 11 or 12.

But based on the reflectance of the sediment off shore, it looks like it may not have been a calving event, but rather a lot of melt water flowing out.

TenneyNaumer

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1173 on: January 17, 2016, 11:31:36 PM »
Jason Box is attributing the effect to katabatic winds forming a polynya.  See updates to Mauri's post.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1174 on: January 18, 2016, 12:46:41 AM »
Jason Box is attributing the effect to katabatic winds forming a polynya.  See updates to Mauri's post.

Thanks for the update.

Edit: Mauri provides other Tweets on this matter at the following linked website:

https://twitter.com/realglacier?ref_src=twsrc%5Etfw
« Last Edit: January 18, 2016, 01:20:47 AM by AbruptSLR »
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1176 on: January 18, 2016, 10:32:20 AM »
Just for the record, johnm33 appears to have been the first to report this, based on the Hycom salinity animation, at the Store Glacier forum at 11:36 AM on January 16, 2016.

Independently TenneyNaumer used Climate Reanalyzer and manati satellite (ASCAT METOP-A) to which ASLR added  tidal data, nullschool surface wind and temperature, Earth Ocean Current & SSTA maps, West Greenland Current and Hurricane Alex considerations, to which Mauri Pelto added low resolution Radarsat-2 and Sentinel-1 from DMI, data from automatic weather stations of PROMICE, surface mass balance from Polar Portal, Illulisat webcam imagery, and observer reports of a foehn event [warm strong downslope winds that descend in the lee of a mountain barrier, katabatic winds].

Very impressive to see folks collaborate in marshalling all the available resources so quickly!

http://forum.arctic-sea-ice.net/index.php/topic,1462.msg68416.html#msg68416
http://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

For event context, I pulled up the Navy animations yesterday for the last 30 days and for the last 12 months, cropped them to either all-Greenland or just Baffin Bay/western Greenland, and resized them 3x. However the underlying data just doesn't have the necessary resolution to provide any real benefit to this. They're large files and already properly served at the original site.

Overall it reminds me of years past when I posted an early spring animation of water seeming to surge through Nares Strait. This was pooh-poohed as a visual artifact or outright error in Hycom data because Nares is frozen solid then. Later we learned from Andreas Muenchow that in fact AW water does surge through the straits year-round, below the ice as needed.

Mauri writes that the ice melange in front of Jakobshavn has been largely removed. Here we need to look for whatever IW grade Sentinel 1A images are available for confirmation at 10 m. I've re-attached the key 10 Jan 15 Sentinel image posted in #1160. This radar gets a weak return (dark) from smooth areas, none from salt water (black), and bright returns from heavily crevassed calving fronts.

The Sentinel hub is not showing any further IW GRDH scenes since but I am pulling down something now from 16 Jan 15, things have iced up a bit:

S1A_EW_GRDH_1SDH_20160116T101533_20160116T101637_009518_00DD20_AAE9
Download URL: https://scihub.copernicus.eu/dhus/odata/v1/Products('43182bf8-ae5a-4020-970c-e2a0b0be3fb4')/$value
Mission: Sentinel-1; Instrument: SAR-C; Sensing Date: 2016-01-16T10:15:33.651Z; Size: 1.08 GB

If the ice really has cleared out, this presents a fabulous opportunity to get into the fjord with multibeam sonar and determine -- at long last -- what the bathymetry is like, maybe even get to the Jakobshavn sill interface cavities and drainages along the lines of recent Rignot work. However it is rather dicey to hang a half-million dollar sonar off the front of a boat in January darkness as ice conditions could change in a hurry.

We puzzled earlier over the current degree of Jakobshavn calving front retreat. In terms of enhancing the winter calving rate by removing buttressing, its significance varies quite a bit from glacier to glacier in western Greenland. And it's fair to say it varies even more in the scientific literature, buttressing varying from dominant effect to near irrelevancy (and back again, for the same glacier!).
« Last Edit: January 18, 2016, 12:10:39 PM by A-Team »

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1177 on: January 18, 2016, 11:56:00 AM »
"Just for the record, johnm33 appears to have been the first to report this, based on the Hycom salinity animation, at the Store Glacier forum at 11:36 AM on January 16, 2016."
I think these were two distinct [but related] events so all credit to Tenney on this.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1178 on: January 18, 2016, 12:10:39 PM »
I provide the following extract from the Robert Scribbler article that wili linked to:

Extract: "Sediment hitting water in this way would be a sign that a very large volume of water had been expelled along the basal zones of the Jacobshavn. In addition, the ice itself appears to have been forcibly ejected. This apparent sediment flush, the concave bowing of sea ice away from Disko and Uummannaq and the inland recession of the calving face are all indicators that something terrible is afoot in Western Greenland."

An expulsion of basal melt-water from the bottom of Jakobshavn could have been facilitated by the relatively high-tides helping to partially lift the glacier near the grounding line, thus reducing the contact pressure sufficiently to allow the basal melt-water pressure to break the seal at the grounding line.
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1179 on: January 18, 2016, 12:54:36 PM »
Mauri also considers sediment (till from underneath the south branch) but seems to back away from that idea. There is a more or less constant stream of till from the north branch being abraded away from a nunatuk (rather than from underneath the ice sheet). That's been going on for years.

We have never seen any sediment coming from the main channel even during peaks of summer melt lake, moulin action, calving, or high tides. Radar satellites cannot detect solids suspended in (high dielectric) sea water.

The only turbidity measuring devices in Greenland that I am aware of are at the bottoms of steam bore holes at Swiss Camp and Store Glaciers where they got left after their wire lines to the surface snapped from glacier deformation. It's possible that someone is measuring fjord turbidity at an Illulisat tide gauge.

The primary tool for confirming sediment is Landsat bands 432 as natural color RGB which Joshua Stevens of NASA kindly provided around the time of the record August calving event.

On those images, which are color-corrected for Rayleigh scattering and other atmospheric effects between satellite and ground, you can very clearly see sediment in some lakes below the south branch and also to the north but nothing for Jakobshavn Isbrae itself.

Of course, it will be another month before Landsat8 kicks in again.

Rob Simmon provides a tutorial on that process at  http://earthobservatory.nasa.gov/blogs/elegantfigures/2013/10/22/how-to-make-a-true-color-landsat-8-image/ as Tom Patterson of the National Parks Service that also includes pansharpening: http://www.shadedrelief.com/landsat8/introduction.html

I relocated the original images back in #901 of 20 Aug 15:

The originals are 17481 × 17581 pixels so only 1/34th is shown. Their processing is really fantastic at distinguishing clear water, till water, muddy water, algal lakes, berg-filled meltwater and wet areas from nunataks and similar. Those 3000x3000 pixel 15 m images without the captions are stored at:

http://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86436/jakobshavn_oli_2015228_lrg.jpg
http://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86436/jakobshavn_oli_2015212_lrg.jpg
http://earthobservatory.nasa.gov/IOTD/view.php?id=86436&eocn=home&eoci=iotd_readmore (story)
http://forum.arctic-sea-ice.net/index.php/topic,154.msg61285.html#msg61285

I also discussed the AGU2015 seismic and airgrav abstracts a few posts back. They provide the first evidence for ~50 m thick till at some sites under the south branch. So there is sediment available but it is mostly being discussed in terms of weak rheology (ice not making contact with bed).

At this time of year, below-glacier conduit channels have frozen back in, at least for neighboring Russell glacier. If there was say rain associated with the hurricane that got under the ice stream, its flow would be distributed.

In summary, we are not looking at a major sediment-releasing event here. However there is very little about Jakobshavn's behavior in recent years that is reassuring and extreme developments cannot be ruled out.
« Last Edit: January 18, 2016, 04:47:57 PM by A-Team »

johnm33

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1180 on: January 18, 2016, 02:15:00 PM »
"An expulsion of basal melt-water from the bottom of Jakobshavn could have been facilitated by the relatively high-tides helping to partially lift the glacier near the grounding line, thus reducing the contact pressure sufficiently to allow the basal melt-water pressure to break the seal at the grounding line."
I think that nails it,  with the next big tides around 24th which will indicate whether there's a persistent build up of meltwater. Tide table,  http://www.dmi.dk/fileadmin/user_upload/vandstand_txt_pdf/2016/Ilulissat2016.pdf

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1181 on: January 18, 2016, 02:38:10 PM »
A-Team.

I like your point:

Quote
In summary, we are not looking at a major sediment-releasing event here. “

(punktum, Punkt, full stop).

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1182 on: January 18, 2016, 04:49:56 PM »
This is fun.

Attached the blended sea/ice surface temperature for Jan.-15, 2016 15:10 UTC for this event. There is more and now I want the evolution of this event.

EDIT: It is actually raw Brightness Temperature on Band 32 (11.770-12.270 µm) as I put the derived ice and sea surface temperatures into a different column in the text file from which the colors are drawn for different variables.
« Last Edit: January 18, 2016, 06:12:38 PM by Andreas Muenchow »
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1183 on: January 18, 2016, 05:28:25 PM »
"An expulsion of basal melt-water from the bottom of Jakobshavn could have been facilitated by the relatively high-tides helping to partially lift the glacier near the grounding line, thus reducing the contact pressure sufficiently to allow the basal melt-water pressure to break the seal at the grounding line."
I think that nails it,  with the next big tides around 24th which will indicate whether there's a persistent build up of meltwater. Tide table,  http://www.dmi.dk/fileadmin/user_upload/vandstand_txt_pdf/2016/Ilulissat2016.pdf

While I have no evidence that there was (or was not) a major sediment release, I do note that the pressure in the basal melt-water is not constant and that if there was a surface ice melt event triggered by the above freezing temperature at that time, then this surface melt-water would likely quickly communicate pressure to the basal melt-water (through the fractured glacial ice), thus temporarily increasing the basal pressure until the outburst released the pressure.  By this line of logic normal high-tides would not release a large outburst, due to insufficient water as their normally is not a (hypothetically) large amount of surface ice melt.
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1184 on: January 18, 2016, 06:25:24 PM »
Quote
This is fun? Attached is raw Brightness Temperature on Band 32 (12 micron) for Jan.-15, 2016 15:10 UTC.now I want the evolution of this event.
Just chasing down glacier names and the action on the land side ... this coastline comes out poorly at low resolution making it hard to see the channels and connections

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1185 on: January 18, 2016, 06:47:01 PM »
The animation shows what is actually a very clever bit of javascript by N Holschuh at PSU. If you go to the link, you can seamlessly mouse-over the controller to pick the next frame. This is a big improvement over animated gifs, as explained over at Zachariae and Developer's Corner (where I adapted the code to better suit our forum constraints, posting it as txt attachment). He did a number of other glaciers in the same format, including Pine Island and Thwaites.

I've also found a way to do a comparison slider of two images (as in before/after 14 Aug 15 calving event, see RGB pieces above) that will actually display correctly within constraints of the forum (which has to be very intolerant to advanced features for hacker reasons).

Both can be done as a 'mail merge' for people who'd rather use MS Office than geek. Basically, just list the urls leading to your files, it will do the rest. These files are normally the same pixel size and geo-registered. Alternatively, some of the frames can be animations. They can be png, jpg and tif, any mix, to retain bit depth and a full color range.

http://nholschuh.com/glaciers.htm
http://forum.arctic-sea-ice.net/index.php/topic,1259.msg68520.html#msg68520
http://forum.arctic-sea-ice.net/index.php/topic,400.msg68521.html#msg68521
« Last Edit: January 18, 2016, 07:03:56 PM by A-Team »

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1186 on: January 19, 2016, 05:50:09 PM »
"An expulsion of basal melt-water from the bottom of Jakobshavn could have been facilitated by the relatively high-tides helping to partially lift the glacier near the grounding line, thus reducing the contact pressure sufficiently to allow the basal melt-water pressure to break the seal at the grounding line."
I think that nails it,  with the next big tides around 24th which will indicate whether there's a persistent build up of meltwater. Tide table,  http://www.dmi.dk/fileadmin/user_upload/vandstand_txt_pdf/2016/Ilulissat2016.pdf

While I have no evidence that there was (or was not) a major sediment release, I do note that the pressure in the basal melt-water is not constant and that if there was a surface ice melt event triggered by the above freezing temperature at that time, then this surface melt-water would likely quickly communicate pressure to the basal melt-water (through the fractured glacial ice), thus temporarily increasing the basal pressure until the outburst released the pressure.  By this line of logic normal high-tides would not release a large outburst, due to insufficient water as their normally is not a (hypothetically) large amount of surface ice melt.

Attached is an illustration of the basal lubrication from subglacial lakes for the Byrd Glacier (which flows from the EAIS into the Ross basin Antarctica).  If such a mechanism were to be periodically triggered for the Jakobshavn, and/or adjoining, Glacier(s),  then we might see periodic outbursts of basal water from these key Greenland glaciers.  Note that uneven bottom conditions promote the accumulation of meltwater into subglacial lakes.
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1187 on: January 20, 2016, 12:45:28 AM »
I have no idea whether the two indicated strong low pressure systems forecast by the Nullschool to be located off the coast of Greenland will have any effect on the mélange in front of Jakobshavn or not.  The image show the Earth Surface Wind and MSLP, and the Earth Surface Wind and Temperature, Map respectively.
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1188 on: January 20, 2016, 12:56:12 AM »
"An expulsion of basal melt-water from the bottom of Jakobshavn could have been facilitated by the relatively high-tides helping to partially lift the glacier near the grounding line, thus reducing the contact pressure sufficiently to allow the basal melt-water pressure to break the seal at the grounding line."
I think that nails it,  with the next big tides around 24th which will indicate whether there's a persistent build up of meltwater. Tide table,  http://www.dmi.dk/fileadmin/user_upload/vandstand_txt_pdf/2016/Ilulissat2016.pdf

While I have no evidence that there was (or was not) a major sediment release, I do note that the pressure in the basal melt-water is not constant and that if there was a surface ice melt event triggered by the above freezing temperature at that time, then this surface melt-water would likely quickly communicate pressure to the basal melt-water (through the fractured glacial ice), thus temporarily increasing the basal pressure until the outburst released the pressure.  By this line of logic normal high-tides would not release a large outburst, due to insufficient water as their normally is not a (hypothetically) large amount of surface ice melt.
I check out
 http://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim365d.gif
 ,well normally the 30day, every week or two just to get an idea of the flow through the archipelago, best if you Ctrl+++ until it stops growing. I noticed in dec. what looked like a massive outburst from Uummannaq bay but couldn't find anything that looked like a positive confirmation of it. If you take a look you'll see a very similar sized outburst just took place in Uummannaq but this time simultaneously in Disko, and points south to some extent [just before it switches back to last year]. On Nullschool at the start of the recent outburst the 2m temp was -15c and drifted up a little over the next few days. So my guess,[after Aslr] which is all it is, is that the tide lifted the ice enough to allow basal water to break out. Lets not forget that the tides work on landmasses too so presumably on ice. The outflow stretched 100k+ out to sea so only the finest sediment  would remain at the surface and perhaps that formed the basis for ice crystals to form, or maybe it was just ice crystals? the basal water would be at 0c and probably close to phase transition anyway, and it looks like this was repeated with every tide for a few days. The question [for me] is how much of this basal meltwater remains, if there's a repeat event around the 24th full moon or the 8th new moon tides that would indicate a lot.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1189 on: January 20, 2016, 01:11:45 AM »
John, why would you expect a further outbreak? Must be a highly non-linear process that drove such a potential outburst, so I cannot see how this would not have drained the potential for a further event.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1190 on: January 20, 2016, 06:17:03 AM »
southwest greenland has been getting moist air inflow forawhile now. iexpect some action there soon.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1191 on: January 20, 2016, 08:57:11 AM »
I have no idea whether the two indicated strong low pressure systems forecast by the Nullschool to be located off the coast of Greenland will have any effect on the mélange in front of Jakobshavn or not.

I have been following said storms (and their predecessors) for a while now. See e.g.

Hurricane Alex Heads for Greenland

et seq.

Here's the latest chart from the NWS OPC. No hurricane force winds just at the moment, but there is a "rapidly intensifying"!

Note also the persistent easterly winds and 7 °C temperatures in Ilulissat yesterday.

« Last Edit: January 20, 2016, 11:17:12 AM by Jim Hunt »
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1192 on: January 20, 2016, 09:14:34 AM »
John, why would you expect a further outbreak? Must be a highly non-linear process that drove such a potential outburst, so I cannot see how this would not have drained the potential for a further event.
Plinius, not sure I expect it, rather hope not but with two breakouts in the bag it's certainly possible. Worst case scenario the internal basin is overflowing and replenishing the basal waters beneath the glaciers.

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1193 on: January 20, 2016, 09:41:34 AM »
I'd like to suggest an alternative hypothesis to that of the breakout of subglacial waters, caused by high tides.

It builds on a) Jason Box' suggestion that strong offshore winds might be the prime cause, and b) Andreas Muncheow' report that the event was characterised by an increase in Sea surface Temperatures.

I suggest that the event was a convective overturn of the water column in the fjords.

The strong offshore winds drove the initial surface waters offshore, drawing up warmer, deeper water to the surface. In turn, these warmer waters were driven offshore, causing the temporary melt seen in the sea ice.

It is also possible that a density instability in the water column builds up over the winter as the surface waters cool, and the offshore winds triggered a density-driven overturn of the waters.  A density-driven overturn of water would be faster, and more effective than just a wind-driven convection, for providing a temporary burst of warm water to the fjords, and available to be driven offshore.

The "flash-melt" seen in the satellite imagery associated with this event reminds me that two or three years ago we saw a large-scale "flash-melt" in the southern Kara Sea in winter. That  Kara event was also almost certainly caused by a convective overturn of ocean waters.

 

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1194 on: January 20, 2016, 11:43:33 AM »
P.S. Here's Wunderground's version of the weather in Ilulissat for the week beginning January 10th 2016. Winds up to 85 km/h gusting to 97 km/h:
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1195 on: January 20, 2016, 11:54:14 AM »
Timothy A, thanks for getting the Jakobshavn forum back on track. On these fast-breaking events, the initial flash commentary naturally gets some things right and some things wrong; with the internet, both persist. Later commentators may see more of the latter than the former and inadvertently add more sand to the castle.

In the dark of winter, when satellites can't see anything in the visible, it is imperative to review what exactly they are sensing and how that proxy is interpreted and processed into a visible image product. For example, just a very subtle break in the color palette centered around a salinity freshening event can create a dramatic illusion of bulk transport, movement that didn't actually occur.

In my view, this was strictly an event within the realm of physical oceanography. Andreas Muenchow is the only forum member with demonstrated competency in that discipline (44 papers cited 1041 times) so even his preliminary comments should be given great weight.

Jason Box has not published in this field but has many important papers on the land side, notably http://tinyurl.com/jcsf6u7 on the 2012 runoff. See also https://www.researchgate.net/profile/Jason_Box/publications for his 170 papers and respectable cite count (over 69% of mine but surprisingly only 33% of E Rignot's). Rignot's group produced the critical channel bathymetry data that Andreas M would need for oceanographic modeling.

To summarize, there is no observational evidence at this time in support of a noteworthy discharge of fresh water or sediment from under the Jakobshavn ice stream. Instead the hurricane remnants merely blew the melange out of the fjords, overturning a lot of water in the process, making this a twofold experimental gift:

-- how big are the hiccups in ice stream velocity when buttressing is suddenly removed at various glaciers?

-- how much mixing of surface (PW) with deeper (denser warmer AW) waters came about?

We could pursue the first of these with Sentinel 10 m but so far no one has done that. For the latter, re-read the three recent papers from the Holland group and await further word from Andreas M. He has access to better oceanographic products, the experience in interpreting them, and the capacity to run oceanographic models.

A central issue with Jakobshavn-meets-the-ocean is the sill at the far western end of the fjord. It is too high to allow much AW waters in. However the sill has a gap in the NE whose height is still uncertain.The other issue is churning of otherwise stably stratified waters at the face of the calving front. That comes about from basal meltwater jets, calving processes themselves, and potentially here, high winds from the east.

http://efdl.cims.nyu.edu/publications/refereed/jpo_jig_part_1_2015.pdf
http://tinyurl.com/hapq9p5  part II
http://www.the-cryosphere-discuss.net/9/4583/2015/tcd-9-4583-2015.pdf
http://www.nature.com/ngeo/journal/v1/n10/full/ngeo316.html

The hurricane might have brought rain; western Greenland is peppered with AWS weather stations but it seems no one has checked them. The Illulisat airport would surely have excellent records too (Jim H is on this above). Heavy rain at the 1500 m contour or above would be quite remarkable any time of year, unprecedented for mid-January.

I'm inclined to think it didn't happen. The weather brought with the hurricane was not warm enough long enough to produce significant basal meltwater given the low heat capacity of air and its poor thermodynamic coupling with ice surface compared to rain that freezes. The big rain event in late August 2012 had very dramatic effects on the land-terminating glaciers to the south, with instructive subsequent journal papers discussed here many times before.

However future rain, especially farther up and farther north, is a huge (and largely imponderable) consideration for western Greenland's future contribution to sea level rise. In terms of ASLR's risk analysis, unforeseen rain on ice is yet another reason to apply the precautionary principle to activities that contribute to further climate change.

« Last Edit: January 20, 2016, 12:32:50 PM by A-Team »

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1196 on: January 20, 2016, 04:22:05 PM »
Timothy A, thanks for getting the Jakobshavn forum back on track. On these fast-breaking events, the initial flash commentary naturally gets some things right and some things wrong; with the internet, both persist. Later commentators may see more of the latter than the former and inadvertently add more sand to the castle.

Very nice post, that makes a great deal of sense.
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1197 on: January 20, 2016, 10:50:08 PM »
Please note that surface skin temperature are at and below the freezing point of seawater (~ -1.7 C). The only reason I displayed the thermal MODIS image is that it distinguishes open water (or very thin ice called nilas) from the regular sea ice, if no clouds are present.

The MODIS image is largely free of clouds, but the solid red pattern does NOT indicate hot water or vertical convection. All it means is that this area transmits more thermal radiation (=heat) to the satellite sensor than the adjacent areas covered by sea ice. The image was meant to help interpret the radar imagery which can see through clouds, but radar signals are a measure of surface roughness at very small scales that scatter some of the energy back that the radar sents out. The faint difference in radar signals can at times be hard to interpret as a layer of dust or thick clouds or some low-level atmospheric inversion or rain can dramatically alter radar imagery. The MODIS thermal image basically rules out these other possibilities.

I do not think that convection of an entire fjord and adjacent coastal areas are possible given the very strong vertical stratification that dominates most fjords in Greenland and elsewhere.

All in good fun ...
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AbruptSLR

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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1198 on: January 20, 2016, 11:29:22 PM »
All in good fun ...

This raises a third possibility that a surface ice melting event was correlated with the katabatic wind event, and that the mélange moved due to a combination of both wind and current.

Edit: In the spirit of good fun, I note that the 2002 collapse of the Larsen-B ice shelf (Antarctic Peninsula) was associated with both katabatic winds that promotes ice surface melting that causes hydrofracturing of the ice shelf when the surface melt-water penetrated crevasses in the ice shelf (I believe that katabatic wind warm-up as they fall down-hill under gravity due to their density).

Edit2: The following link discusses "Downslope Winds"

http://www.atmos.washington.edu/2008Q4/505/Lab6_downslope_winds.pdf
« Last Edit: January 21, 2016, 12:11:19 AM by AbruptSLR »
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Re: Jakobshavn Isbræ / Ilulissat Isfjord / West Greenland
« Reply #1199 on: January 21, 2016, 12:37:35 AM »
Abrupt: Doesn't necessarily need to be katabatic - breaking through Foehnstorm might suffice. But yes, was exactly what I was just about to ask: Why don't we just assume that a strong storm blew out of the Fjord. Another indication for this is the marked structure of almost full coverage fine-grained ice at the rim of the open area, which would be fine, young ice pushing into the retreating ice front.

@Johnm33: I am not sure I can follow this. Why should there be a giant lake in the Greenland basin? To all I know that is almost 100% ice there.