Please support this Forum and Neven's Blog

Author Topic: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland  (Read 254729 times)

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #100 on: April 13, 2014, 01:04:47 PM »
It is fascinating to watch how a huge glacier like Zachariae Isstrøm is moving, this animation is based on 2 images from March 22 2014 and April 11 2014 or 20 days apart, and it is easy to see the whole glacier moving:

Please click on image to start animation!
« Last Edit: April 13, 2014, 03:03:07 PM by Espen »
Have a ice day!

icefest

  • ASIF Citizen
  • Posts: 258
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #101 on: April 13, 2014, 02:17:37 PM »
It's incredible that the older icebergs are still frozen in the FYI, while the rest of the glacier pushes the closer ones along.
Open other end.

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #102 on: April 14, 2014, 09:29:51 PM »
"Just out of the satellite" further movement at Zachariae Isstrøm, and now a "Sea Ice Tsunami"  is clearly seen (2nd frame) in front of the calving front:

Please click on image to start animation!
« Last Edit: April 14, 2014, 10:22:53 PM by Espen »
Have a ice day!

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #103 on: April 15, 2014, 06:39:09 AM »
Here is a composite of ice surface contour,ice surface velocity, and bedrock. For detail and bedrock contour go to

http://membrane.com/sidd/greenland-2013/

and

http://membrane.com/sidd/greenland-2013/convel.html

werther

  • ASIF Middle Class
  • Posts: 705
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #104 on: April 15, 2014, 10:58:04 AM »
Morning all,

for everyone that wants to have a close look on this area this summer. Polarstern will be there with Andreas Muenchow on board. Follow his new blog entry here:
http://icyseas.org/2014/04/14/north-greenland-glacier-ice-ocean-interactions-2014/

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #105 on: April 15, 2014, 07:52:20 PM »
It's a pity, Zachariae Isstrøm is not calving Ice Islands like Petermann, because what is happening with this glacier I find far more important than most of the other glaciers in Greenland.
Have a ice day!

Andreas Muenchow

  • ASIF Lurker
  • Posts: 63
    • View Profile
    • IcySea
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #106 on: April 15, 2014, 11:59:57 PM »
Not sure I agree with that sentiment, Espen, but the contrast between the collapsed Zachariae and the apparently stable Niogshalvfjerdsfjorden certainly raises a number of interesting questions that the Greenland ice sheet story is not as simple and straightforward as some political factions want us to believe ;-)
A Sailor in a Changing Climate
http://IcySeas.org

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #107 on: April 16, 2014, 06:12:22 AM »
Now the back pressure is gone, it is natural the ice will flow in the direction where Zachariae is and 79 will probably stay relatively stable and just melt slowly away.
Have a ice day!

Andreas Muenchow

  • ASIF Lurker
  • Posts: 63
    • View Profile
    • IcySea
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #108 on: April 16, 2014, 03:37:56 PM »
Fair and descriptive enough; but the question stands on why the back-pressure disappeared at Zachariae but not at Nioghalvfjerdsfjorden?
A Sailor in a Changing Climate
http://IcySeas.org

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #109 on: April 16, 2014, 08:31:08 PM »
Hi Andreas,

I believe it is sea and current related, the process started in the early 2000s, especially 2003 stands out, the whole sea in front of Zachariae and 79 was literally sea ice free in 2003:
https://forum.arctic-sea-ice.net/index.php/topic,238.msg7988.html#msg7988
After 2003 Zachariae started to disintegrate from the south and inside Jøkelbugt, in the period before 2003 not much happened to both Zachariae and 79, but between 2003 and 2012 the disintregation of Zachariae continued and reached the southern point of Lambert Land ( Kap Zachariae )  this I disscussed with Mauri Pelto then
http://glacierchange.wordpress.com/2012/08/27/zachariae-isstrom-further-retreat-ne-greenland/
When Jøkelbugt became ice free up to Kap Zachariae, Zachariae Isstrøm woke up, the back-pressure was not there and the whole glacier started to move and at a fairly high speed, and this process has continued during the winter and spring of 2014.
https://forum.arctic-sea-ice.net/index.php/topic,400.msg24181.html#msg24181

Why did this reaction to changes at sea happen to Zachariae "only".

Several reason I belive.

1. With no back pressure it is more natural for the ice from GIS to go trough the Zachariae Gate than the 79 Gate or the Storstrømmen Gate there are simply fewer topographical obstacles on the Zachariae Gate route.

2. I also think sea temperature and currents changed dramatically after 2003 especially in the bay in front of Zachariae Isstrøm (Jøkelbugt), even huge ice pieces from the glacier seems to melt even before they get out of the bay and into the sea outside.
What was the reason for the sea changes in and around 2003?
I think you have more theories and facts on this matter, but I believe there is a relative high average sea temperature difference between Zachariae Isstrøm and 79?

Please on image to enlarge!
« Last Edit: April 16, 2014, 10:34:01 PM by Espen »
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #110 on: April 16, 2014, 09:31:22 PM »
A new animation March 22 - April 16 2014 from Zachariae Isstrøm:

Please click on image to start animation!

Have a ice day!

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #111 on: April 16, 2014, 09:41:50 PM »
" ... fewer topographical obstacles on the Zachariae Gate route."

That is also what i see in bedrock contours as linked from in

http://membrane.com/greenland-2013/sidd/convel.html

 I wonder how far back there is sea water penetration into the subglacial hydrology as in Lewis(2009) DOI: 10.1002/hyp.7343

I enclose two images from fig 4, the second is the legend, the first is the NE quadrant of GIS. The Figure caption is the text below:

Figure 4. Meltwater evidence along the ice sheet perimeter (number of confirmed meltwater features within a 50-km vicinity of a modelled outlet) versus meltwater intensity (total annual meltwater volume per unit thawed area, cm) within each hydrologic sub-basin, illustrating that rivers, streams, and proglacial lakes are generally more prevalent near ‘wet’, hig–producing modelled meltwater outlets than ‘dry’, low-producing outlets (as seen in similar size variations in blue and red circles). Modelled hydrologic flow network delineates realized (‘wet’, solid lines) and unrealized (‘dry’, dashed lines) drainage patterns

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #112 on: April 16, 2014, 09:43:55 PM »
I should point out that the Lewis paper is based on the 2001 Bamber dataset (the paper predates his 2013 dataset, which is what i am using)

sidd

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #113 on: April 17, 2014, 08:55:02 AM »
Detail animation of the Zachariae calving front based on Landsat 8 images processed for natural color at 15m resolution. Images form March 13 to April 14 were used.
Watch a new crack opening.
In the last frame an arrow indicates my best estimate of the ice movement: 10pix right and 2pix down, translating to 152 m in 32 days or 4.8 m/day with perhaps an error of +/- 15%.

(click the pic for that animation)

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #114 on: April 17, 2014, 01:17:06 PM »
The Nioghalvfjerdsfjorden is moving much slower indeed. Attached sequence shows a channel at the center of the glacier dated 2013 September 6 and 2014 April 2.
The ice moved 14pix right and 1 pix up. Total movement is 210m in 208 days giving an average velocity of 1m/day with an error of about +/- 10%.

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #115 on: April 17, 2014, 05:59:53 PM »
One more to establish the velocity of the Zachariae. Dates as in the previous post: 2013 September 6 and 2014 April 2.

There is a nice little hexagon shaped feature in the ice that makes is easy to match pixels in the two images. I get 78pix to the right and 6 pix down. That is 1173m in 208 days, a velocity of 5.64 m/day with maybe 3% margin of error.
Picked another feature and got the same number so the velocity is quite uniform in the middle of the ice stream. Both measurements are marked with an arrow.


Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #116 on: April 17, 2014, 06:20:28 PM »
Wipneus it would be interesting to see how the velocity is compared to last year, my gut feeling tells me Zach is accelerating?
Have a ice day!

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #117 on: April 17, 2014, 06:40:42 PM »
Wipneus it would be interesting to see how the velocity is compared to last year, my gut feeling tells me Zach is accelerating?

That is exactly what I have in mind in "watching the giants waking up". Unless you find a suitable earlier Landsat 8 image that means going to landsat 7 images that are not as nice and take days to order from the USGS. Of course we will also watch the progress during the coming season.

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #118 on: April 17, 2014, 11:35:57 PM »
Attached image is closeup of bedrock topo at the mouth of Nioghalvfjerdsfjorden and Zachariae from Bamber-2013. Zachariae is connected through deeper channels to the future inland sea.

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #119 on: April 18, 2014, 07:46:29 AM »
And not to mention the Delta shaped outlet at Zachariae Isstrøm against the Arrow shaped outlet at 79?
Have a ice day!

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #120 on: April 18, 2014, 08:45:34 AM »
Espen pointed to a landsat 8 image taken on 2013 May 25. That gives us an opportunity to estimate the ice velocity of the Zachariae during the last melting season.
This image is taken on the ascending half of the landsat 8 orbit. That is normally the night side, but in the Artic summer that does not matter. The orientation of the image is slightly different though so I had to do some rotation to align images using the nearby rocky islands.

The hexagon-shaped feature is there as well. It moved during 104 days 42pix right and 8pix down. That translates to 641m, or 6.2 m/day. I estimate an error of about +/- 0.4, due to the manual image manipulation that was required.

So no speed-up can be seen this way. I am not sure if the speed of such glaciers is expected to vary much between the seasons?

(click the pic for a rather nice animation)

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #121 on: April 18, 2014, 12:40:27 PM »
Added 2012 July 9 to the sequence. I decided that for the purpose of measuring velocity color is not required. With some searching the hexagonal feature can be found.
Distance traveled 2013 Sep 6 is 144 pix to the right 21 pix down. That is 2183 m in 423 days or 5.2 m/day. Not much acceleration to be seen but it depends on the accuracy of the 2013 May 25 data point, if taking the difference with that date I get about 3.9 m/s. I really need more data points.

In the animation look at the glacial lakes, they stay in the same place while the local ice is moving.

(click for that animation on the picture)

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #122 on: April 18, 2014, 08:49:08 PM »
"ook at the glacial lakes, they stay in the same place while the local ice is moving."

That is quite amazing, how can that happen. I find it hard to believe that the ice somehow flows "around" the lake depression ...

sidd

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #123 on: April 18, 2014, 09:06:22 PM »
Sidd,

The glacial lakes are located where the ice is more or less stationary (they are not situated in the actual stream) , there is probably a new future Kap below?
I think that can be observed on your bedrock map above?
« Last Edit: April 18, 2014, 09:55:52 PM by Espen »
Have a ice day!

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #124 on: April 18, 2014, 11:05:23 PM »
I have asked Prof. Pelto to look. He indicates he may be able to do so this weekend.

i think the answer may be that the lakes reform in the same place year after year. Could the depressions they form in be a feature of the flow like stationary ripples in a stream ?

sidd

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #125 on: April 18, 2014, 11:20:41 PM »
Added 2012 July 9 to the sequence. I decided that for the purpose of measuring velocity color is not required. With some searching the hexagonal feature can be found.
Distance traveled 2013 Sep 6 is 144 pix to the right 21 pix down. That is 2183 m in 423 days or 5.2 m/day. Not much acceleration to be seen but it depends on the accuracy of the 2013 May 25 data point, if taking the difference with that date I get about 3.9 m/s. I really need more data points.

In the animation look at the glacial lakes, they stay in the same place while the local ice is moving.

(click for that animation on the picture)

That is about ½ the amount / day compared to Jakobshavn (width x velocity) pretty impressive this far north? Or am I wrong?
Have a ice day!

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #126 on: April 19, 2014, 12:09:53 AM »
The following image is a close up of the ice surface
along Nioghalvfjerdsfjorden and Zachariae Isstrom.
Note that ice is piling up behind the first, but not the
second. The warming ocean reaches deeper under Zachariae.
Zachariae is a wider and deeper connection to the future inland
sea.


sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #127 on: April 19, 2014, 05:54:50 AM »
I knew i had a more recent ref to basal hydro than Lewis(2009)
Linvingstone(2013) fig 5b) attached, putative subglacial hydro, subglacial lakes, rignot velocity in obe pic

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #128 on: April 19, 2014, 06:02:06 AM »
sorry ref for the last is

doi:10.5194/tc-7-1721-2013

open access

also, in light of my supposition that the (supra) glacial lakes reform in the same place because of flow features in the ice surface, see Sergienko(2013)

doi: 10.3189/2013JoG12J040

not open, but i attach fig 2, illustrating effect of bed topo on surface

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #129 on: April 19, 2014, 09:10:29 AM »

also, in light of my supposition that the (supra) glacial lakes reform in the same place because of flow features in the ice surface, see Sergienko(2013)

Thanks for digging that up Sidd. I thinks that is what we are seeing.

mspelto

  • ASIF Lurker
  • Posts: 25
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #130 on: April 19, 2014, 12:27:38 PM »
Nice new images sets from this spring I had looked at the March but not the April Landsat.  The supraglacial lakes form in same geographic location mainly because of the bed of the glacier induces changes in the surface of the glacier.  Depending on the speed of movement and ablation rate, the lake could persists or not.  The lakes form because of the surface features, but do not necessarily disappear as they move beyond that feature. Lampkin (2011) is a paper that best describes the bed-surface relationship and lag. http://onlinelibrary.wiley.com/doi/10.1029/2010JF001725/abstract

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #131 on: April 19, 2014, 10:15:45 PM »
Thanks for the comment, Prof. Pelto. There is another paper in 2011 by Lampkin and VandeBerg (that is how it is capitalized in the journal) in Hydrological Processes DOI: 10.1002/hyp.8170 that is relevant also. I attach Fig 2

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #132 on: April 19, 2014, 10:19:03 PM »
The second name in the last ref i posted should be spelled VanderBerg Sorry.

sidd

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #133 on: April 19, 2014, 10:21:19 PM »
Sidd,

That makes sense, nice digging! ;)

That gives the expression " Sweep under the carpet" a new meaning?
« Last Edit: April 19, 2014, 10:53:22 PM by Espen »
Have a ice day!

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #134 on: April 20, 2014, 09:38:05 AM »
Velocity between mids of 2010 and 2012 is about 4.4 m/day, measured at the hexagon feature which moved 3.148 km in those two years.

I postpone an updated animation until I added some more years and can plot distance vs time. Until then not much sign of significant acceleration in the period considered.

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #135 on: April 20, 2014, 11:40:40 PM »
Comparison of surface contour and bedrock in the subject area
For other such comparisons and some previous work please see

http://membrane.com/sidd/greenland-2013/walkback.html

sidd

Andreas Muenchow

  • ASIF Lurker
  • Posts: 63
    • View Profile
    • IcySea
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #136 on: April 21, 2014, 05:08:12 PM »
Velocity between mids of 2010 and 2012 is about 4.4 m/day, measured at the hexagon feature which moved 3.148 km in those two years.
For context, please note, that Rignot and Kanagaratnam (2006, Science) give a velocity profile across the glacier that peaks at about 1,600 m/y or 4.4 m/day for Zachariae from 2004-05 ;-)
A Sailor in a Changing Climate
http://IcySeas.org

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #137 on: April 21, 2014, 07:05:08 PM »
For context, please note, that Rignot and Kanagaratnam (2006, Science) give a velocity profile across the glacier that peaks at about 1,600 m/y or 4.4 m/day for Zachariae from 2004-05 ;-)

Thank you Andreas, that is nice to know.

Have you any indication how much Summer and Winter might differ from such an  annual average?

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #138 on: April 21, 2014, 08:57:08 PM »
From the Rignot paper, some historic(2000) seasonality variation:

"We examined the seasonal variability in flow
speed of major glaciers in fall 2000. We found
no velocity change from September to January at
the 1% level over the 24-day averaging period of
Radarsat-1. On the Petermann Glacier (1 in Fig.
1), a continuous set of observations in 2004
reveals an 8% increase in the summer months
compared to winter (Fig. 2A). A similar sea-
sonality is detected on Nioghalvfjerdsbrae and
all southeast Greenland glaciers and has been
observed on Jakobshavn Isbrae (8) and Colum-
bia Glacier, Alaska (9). Winter velocities are
therefore only 2% lower than the annual means,
and flow changes must exceed 8% to be sig-
nificant."

I atttach the figure referred to, y axis is meter/year


Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #139 on: April 22, 2014, 10:52:40 AM »
Thanks Sidd, 8% is about 0.4 m/day. Small but not entirely negligible.

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #140 on: May 02, 2014, 11:53:39 PM »
I may have an idea as to why Zachariae is breakig up faster than Nioghalvfjerdsfjorden. I attach a pic showing a trough under the former. Some more detailed discussion is at

http://membrane.com/sidd/greenland-2013/Zachtrough/

with some graphs of the water temperature, and 150, 200m depths (the latter are relevant in the context of the water temperature variation with depth)

Briefly: The trough allows warmer Atlantic Intermediate water to the base of the ice. Also the bed is deeper under Zachariae, and the deepest area is larger.

sidd

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #141 on: May 03, 2014, 10:27:44 PM »
Very interesting, and it makes sense, but the color scheme confuses me a bit. ???
Have a ice day!

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #142 on: May 04, 2014, 12:31:08 AM »
Mr. Espen, apologies for the color scheme. I attach some images with a different scheme.
The first image shows temperature vs depth from Aagard(1968, "The East Greenland Current North of the Denmark Strait:Part 1", Arctic, v21) fig 4. Note that 200m is a good depth to watch.
The second image is temperature vs depth across Fram, eastward from 16W along 79 N. (This is from just east of Norske Oer. Note the lack of Atlantic Intermediate water on the continental shelf.
The third is to show the pathway for warm water from south east. The fourth is a closeup of the
trough and a small ridge from the upper corner of Lambert; the latter provides an additional barrier to Atlantic Intermediate water from the southeast getting under Nioghalvfjerdsfjorden.

sidd
« Last Edit: May 04, 2014, 01:10:35 AM by sidd »

sidd

  • ASIF Upper Class
  • Posts: 1388
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #143 on: May 04, 2014, 01:07:48 AM »
I neglected the reference for the second image, which is Fig 3a) from Fahrbach et al. Polar Research 20(2), pp217-224 in 2001.

sidd

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #144 on: May 04, 2014, 06:43:11 AM »
Nice work Sidd, I wonder what impacts, when the the previous tongue of Zachariae is gone?

And I am surprised of the relative shallow water of the southern part of Jøkelbugt, and the depth of the future "Zachariae Sea" .
Have a ice day!

Wipneus

  • ASIF Governor
  • Posts: 3564
    • View Profile
    • Arctische Pinguin
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #145 on: May 05, 2014, 04:02:19 PM »
Two Zachariae images 2014/4/2  and 2014/5/4 compared. Zachariea keeps moving with an average estimated speed of over 6 m per day.

(click for the animation to start)

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #146 on: May 05, 2014, 05:13:24 PM »
Wipneus, it is amazing to watch this monster, now that we know how fast the thing is moving, it would be interesting to estimate the size of the retreat, which at this point would be much higher?
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #147 on: May 18, 2014, 03:45:46 PM »
An interesting video from NASA showing a retreating grounding line works:

The link is below

GroundingLineRetreat 20140507 1280
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #148 on: May 20, 2014, 09:30:56 PM »
May 20 update, I am pretty impressed how this thing is behaving this season:

Please click on image to start the animation!
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3064
    • View Profile
Re: Zachariae Isstrøm / Nioghalvfjerdsfjorden / North East Greenland
« Reply #149 on: May 22, 2014, 07:45:11 PM »
Zachariae Isstrøm, aka Speedy Gonzachariae, is still on the move, note the new cracks relatively far behind the obvious calving front:

Please click on the image to start the animation!
« Last Edit: May 22, 2014, 08:47:28 PM by Espen »
Have a ice day!