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Author Topic: NØIB (Norske Øer Ice Barrier) / North East Greenland  (Read 10114 times)

Espen

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NØIB (Norske Øer Ice Barrier) / North East Greenland
« on: November 02, 2013, 12:14:23 PM »
In the North East East of Greenland, east of 79N Glacier and Zachariae Isstrøm or about 130 km / 72 Nm east of Kap Zachariae / Lambert Land, is NØIB (Norske Øer Ice Barrier), in the same area is Belgica Bank with its shallow water is also found.
According to many papers the area was historically covered with fast ice during the whole year, but in 2003 the fast ice disappeared , probably for the first time ever in modern time, the fast ice then recovered to some degree again over the years, but in the otherwise cold arctic summer of 2013 the fast ice almost left the scene again, only a small piece NØIB-2013 survived, but why this stubbornness?   


Please click on image to enlarge.
« Last Edit: November 02, 2013, 07:40:12 PM by Espen »
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Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #1 on: November 02, 2013, 05:10:36 PM »
In 1993 the German scientist Geroen Budeus from Alfred Wegener Institute of Bremerhaven discovered the islet Tobias Ø, a small group of islets of approx. 3 km2.


Due to this discovery, Denmark / Greenland gained 825 km2 *) at the law of the sea negotiations with Norway, so there is obviously good reasons to be observant with this “small matters”

*) More than the size of Singapore (710 km2).

Photo: Tobias Ø , Danish Navy.
« Last Edit: November 02, 2013, 06:11:21 PM by Espen »
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Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #2 on: November 02, 2013, 06:01:35 PM »
Some 28 km (15Nm) south east of Tobias Ø, is this years remains from NØIB found, on what is here called NØIB-2013 something very interesting is observed.
On the following high definition Landsat image, shadow making dots are found, these dots could be islets of the same nature as Tobias Ø, this could also explain why NØIB-2013 is still anchored and stuck to where it is today.
The sea depth in this area (Belgica Bank) varies a lot, and sea maps are very unreliable to say it at least (Danish Navy), but sea depths of less than 20 meters are measured by several parties, so icebergs travelling from the north could easily get parked here too.


NØIB-2013 facts:

Size about 138 km2 (September 6 2013).

Position: 79°02′N 14°54′W 130 km / 72 Nm east of Kap Zachariae / Lambert Land.

Please click on image to enlarge:
 
« Last Edit: November 02, 2013, 07:41:33 PM by Espen »
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Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #3 on: November 02, 2013, 06:18:28 PM »
A larger image:

Please click on image to enlarge:
« Last Edit: November 02, 2013, 07:42:32 PM by Espen »
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Wipneus

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #4 on: November 03, 2013, 08:17:03 AM »
Here is a detail, using Landsat's 15 m res panchromatic channel.

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #5 on: November 03, 2013, 09:11:44 AM »
79°20'N, 15°48'W  are according to the Wiki, the coordinates of Tobias Island. It is right in the center of this landsat 15m image, under the hart shaped piece of ice. For scale, this piece is about 1.5km wide.

(click that image)


Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #6 on: November 03, 2013, 10:03:31 AM »
Hello Wipneus,

In that resolution it looks more like icebergs, where do you retrieve  those images from?
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Wipneus

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #7 on: November 03, 2013, 10:13:05 AM »
Hello Wipneus,

In that resolution it looks more like icebergs, where do you retrieve  those images from?

I am using http://landsatlook.usgs.gov/ to select the image. From there, you can "order" the full compressed GEOTIFF image, which is a 900MB download. In that are the various color bands, including a 670MB panchromatic channel. From there I use the Gimp to select the image, and do a simple enhancement. Using Gimp, I loose the 16 bits depth. Don't know how important that is.

ggelsrinc

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #8 on: November 03, 2013, 10:19:57 AM »
Wipneus, I don't know.

The only way I can see to produce your images is to use the broad spectrum on satellites, which pick up multi-things and use the spectrum that picks up other things, that I know of, to cancel them out.

Do I have a clue?


Wipneus

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #9 on: November 03, 2013, 01:07:16 PM »
Wipneus, I don't know.

The only way I can see to produce your images is to use the broad spectrum on satellites, which pick up multi-things and use the spectrum that picks up other things, that I know of, to cancel them out.

Do I have a clue?

The Landsat spectral bands are listed here

The panchromatic band from the Landsat is 0.5-0.68 micro, that is visible light, perhaps without the deepest blues.
Anyway it was obviously chosen for the 15m resolution in order to identify Espens shadowy features. And that seems to work quite good.

ggelsrinc

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #10 on: November 03, 2013, 04:02:01 PM »
Wipneus, I don't know.

The only way I can see to produce your images is to use the broad spectrum on satellites, which pick up multi-things and use the spectrum that picks up other things, that I know of, to cancel them out.

Do I have a clue?

The Landsat spectral bands are listed here

The panchromatic band from the Landsat is 0.5-0.68 micro, that is visible light, perhaps without the deepest blues.
Anyway it was obviously chosen for the 15m resolution in order to identify Espens shadowy features. And that seems to work quite good.

I was thinking about the MODIS shadowy image that AndreusT asked about on the Drift, Deformation and Fracture of Sea thread and figured you would know, though I must admit I was confused posting on the wrong thread to ask your secrets. MODIS has 36 spectral bands from 0.4 to 14.4 micro, which I'm sure you already know and just mentioned for others. AndreusT asked:

Quote
Can somebody explain the dark "shadows" in the images? My guess is that they represent relatively warm surface temps caused by wind moving over snow surfaces of low heat capacity, higher altitude air temps are probably still a lot above these radiatively cooled surfaces. But would like to be able to back this up or be put right.

on reply #15 of this thread:

http://forum.arctic-sea-ice.net/index.php/topic,624.0.html

It looked like clouds to me and I guessed in my mind they used different wavelengths to see clouds than to get high resolution images of the Earth, giving them the ability to remove some of the images of clouds, but not all, therefore leaving some shadows of clouds. I didn't even try to answer, because my knowledge on the subject is limited to light, basically no photography and limited satellite knowledge.

May I ask, what is your opinion on these shadows and is there a good way to learn about this subject? 

http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201311020737.NOAA.jpg

http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201310290501.NOAA.jpg

Even those who completely lack your expertise, appreciate what you have done. Bravo!

Wipneus

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #11 on: November 03, 2013, 06:54:03 PM »
Quote
It looked like clouds to me and I guessed in my mind they used different wavelengths to see clouds than to get high resolution images of the Earth, giving them the ability to remove some of the images of clouds, but not all, therefore leaving some shadows of clouds. I didn't even try to answer, because my knowledge on the subject is limited to light, basically no photography and limited satellite knowledge.

May I ask, what is your opinion on these shadows and is there a good way to learn about this subject? 

Let me state that I don't consider myself having much expertise here. I did work with Landsat images before, which made it possible to present some better definition images on a Sunday morning.

Now, for the shadows on the image. Brightness in a particular spectral range will depend on radiative properties of the surface and its temperature and those of the atmosphere.
Here I would agree that clouds cause darkish shadows. In the Arctic night under clear sky conditions a temperature inversion creates a colder surface compared with the lower atmosphere.  So the satellite will see low clouds that are warmer than some clear surface nearby. That is opposite from other seasons and lower latitudes.

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Even those who completely lack your expertise, appreciate what you have done. Bravo!

Now don't exaggerate.

ggelsrinc

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #12 on: November 05, 2013, 05:57:42 AM »
Humility is too much of a virtue for me to add much more to in comments. I do apologize for taking this thread off theme.

Getting back to the theme of this thread, I was wondering about a few things and had some ideas. It's true we visit such areas via satellite, but what is the nearest place where human beings live year round and I mention that to make a point? That area has major glacier flow and I don't think it was often visited in the past, nor to this day by people living close to it. I imagine it would be a place where fast ice could be easily trapped amongst grounded icebergs that have calved off of that ice shelf and get stuck on the Belgica Bank and some islands, which is merely speculation. It makes me wonder if we could copy mother nature in the past and plug up Fram to some degree, if that speculation is true.

For some reason I keep thinking that area can get polynyas from Katabatic winds, but I don't recall what gave me that impression. The only thing I remember studying is the glacier feeding that area. 



That 79 degree Northeast Greenland area is a very important place on Earth and most worthy of a thread to examine it in detail.

http://icyseas.org/2013/10/31/ocean-circulation-and-melting-glaciers-off-north-east-greenland/

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #13 on: November 06, 2013, 06:04:22 AM »
gglesrinc wrote:

"For some reason I keep thinking that area can get polynyas from Katabatic winds, but I don't recall what gave me that impression"

I recall that the mechanism in Antarctica is katabatic winds forcing sea ice away from shore exposing sea water to very cold air, creating fresh ice and Antarctic bottom water through brine rejection. But I don't think the mechanism works the same way off Greenland.

ggelsrinc

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #14 on: November 06, 2013, 06:50:12 AM »
gglesrinc wrote:

"For some reason I keep thinking that area can get polynyas from Katabatic winds, but I don't recall what gave me that impression"

I recall that the mechanism in Antarctica is katabatic winds forcing sea ice away from shore exposing sea water to very cold air, creating fresh ice and Antarctic bottom water through brine rejection. But I don't think the mechanism works the same way off Greenland.

Quote
Katabatic winds are most commonly found blowing out from the large and elevated ice sheets of Antarctica and Greenland.

Source: http://en.wikipedia.org/wiki/Katabatic_wind

Just to avoid confusion and keep the record straight, I don't claim that's the case in that area, but something in the back of my mind points that way and I don't remember the source. It makes sense considering a Greenland high and how the winds would blow. I haven't examined that area enough to be sure.

Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #15 on: April 22, 2014, 05:05:03 PM »
There is a good chance our friend Andreas will face sea ice free conditions on his trip to this exotic place, later in the season. The break up is ahead of schedule:
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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #16 on: October 02, 2014, 03:13:29 PM »
I think the shadows you refer to Espen in the Landsat image are grounded tabular icebergs. In the area they are typically 5-20m high, that explains the shadows on the N side of the features. 
 

Espen

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Re: NØIB (Norske Øer Ice Barrier) / North East Greenland
« Reply #17 on: October 02, 2014, 05:36:03 PM »
I think the shadows you refer to Espen in the Landsat image are grounded tabular icebergs. In the area they are typically 5-20m high, that explains the shadows on the N side of the features.

No they are real islands?

PS: You will not see the icebergs in the Modis 250m images, they are visible when using the Landsat images.
« Last Edit: October 02, 2014, 05:47:41 PM by Espen »
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