Support the Arctic Sea Ice Forum and Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Sonia

Pages: [1] 2
1
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 09, 2016, 01:31:51 PM »
I thought i'd take a look at last year, just a hint on this image
http://ocean.dmi.dk/arctic/images/MODIS/Kane/20150606TERR.jpg not much more on the next
...
Will the high/low tides coming around the 5/6th be enough?
I like this summary a lot because it shows how the breakup was spread out over a month.  Tides in early June last year anyway might have helped start things but weren't enough for a complete breakup.  This year is looking similar.

Neven is watching for blue ice; he may not have long to wait.  Wipneus observes some melting starting from the AMSR2 data.  http://forum.arctic-sea-ice.net/index.php/topic,382.msg79648.html#msg79648  That's consistent with the recent temperatures at Hans Island.

2
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 19, 2016, 05:33:25 AM »
Have you looked at a GRD IW class Sentinel 1A scene of the rim and bridge? It seems like salt water and salty ice should appear black in radar because of ion dipoles where as frozen freshwater ice would be reflective
Thank you for that explanation.  It's a tip that helps a lot with image interpreation!

3
Arctic sea ice / Re: What the Buoys are telling
« on: August 24, 2015, 01:33:15 AM »
Saw this earlier today from #9. Can someone please tell me what I'm looking at here?
Ice, snow, water, fog.

The green color did catch my eye.  I though it might mean that piece of ice is rather thick.  I've been amazed that the views from O-buoy 9 have continued to be so interesting.

4
Arctic sea ice / Re: Arctic Image of the Day
« on: August 23, 2015, 08:56:45 PM »
I thought "American Gothic" when I saw the photo.  I imagined a pitchfork, no wait, a trident, in the bear's paw.

5
Today's Terra image shows some cracks in the Northeast Water Polynya.  The breakup is happening a little later than in the last two years.

6
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: July 02, 2015, 02:01:18 AM »
I've been watching the moon phases go by, but the wind has been so persistently from the south!  The wind reversed for two days last week.  I held my breath as the mobile ice all shifted south to press against the remaining fast ice, but it all held, both in the Kane and the Hall.  I'm not good with weather but it looks like this south wind will get rather stiff in about two days.  I'll be watching closely then.  Even if all all becomes mobile though it won't mean much for export as long as the wind stays from the south.  The export was interesting last year because the reduced pressure seemed to allow the Lincoln ice to become mobile.  Amazingly it's still sloshing around, but currently with nowhere to go.

7
Arctic sea ice / Re: What the Buoys are telling
« on: June 25, 2015, 02:45:32 PM »
... Reading latitude and longitude from the graph is a bit crude, if it is given somewhere as figures I havn't found it.

Hmm, I know I tracked this down once before... Lets see, navigating from the landing page at http://www.o-buoy.org/...  Ah, this looks like it: https://www.aoncadis.org/dataset/o-buoy9_deployment.html  Also it looks like data is running a few days behind realtime at the moment.

Code: [Select]
(index -> (Time,Latitude,Longitude,speed,course,pitch,roll))
Time[fmt="yyyy-MM-dd HH:mm:ss z"],Latitude[unit="deg"],Longitude[unit="deg"],Speed[unit="knots"],Course[unit="deg"],pitch[unit="degree"],roll[unit="degree"]
2015-01-01 00:01:47,85.1064834595,-58.7592964172,0.159999996424,61.8899993896,-1.85000002384,-2.40000009537
2015-01-02 00:01:43,85.0965499878,-58.7691459656,0.159999996424,61.6500015259,-1.74000000954,-2.40000009537
.
.
2015-06-20 23:01:26,82.515625,-16.5030403137,0.239999994636,149.429992676,-8.39000034332,-3.20000004768
2015-06-21 00:01:27,82.5146331787,-16.4927406311,0.0599999986589,149.440002441,-5.69000005722,-3.20000004768

8
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 08, 2015, 01:18:48 AM »
Hans Island weather station reading above freezing for the first time this year I think.

9
Arctic sea ice / Re: The 2015 melting season
« on: June 03, 2015, 11:57:51 AM »
The Lena delta has clear sky today and images of the melt are beautiful.  Check your favorite imagery source and be sure to turn off annotations such as coastlines.

10
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 25, 2015, 12:14:06 AM »
It's fascinating to me that ice in a large part of the Lincoln Sea has stayed mobile all winter.  It would refreeze for a little bit, then winds would change and the polynyas would open right back up.  The ice is all raring to go as soon as the Nares opens.

11
Arctic sea ice / Re: Northwest Passage thread
« on: May 24, 2015, 07:55:53 PM »
... the narrow passage through Brands and Gibson Islands ...

That's the Bellot Strait.  Scroll back through the topic and there are a number of posts referring to it and to ship traffic through it.

12
Arctic sea ice / Re: The 2015 melting season
« on: May 22, 2015, 11:38:32 PM »
Barrow lost some ice today.  The 1 day radar loop (at http://seaice.alaska.edu/gi/observatories/barrow_radar/recent-radar-animations) currently shows it well. 

13
The snow melt is also striking there.

14
Arctic sea ice / Re: Arctic Image of the Day
« on: March 26, 2015, 12:51:57 AM »
Detail from above link.  I have no idea what would make the loopy line.

15
Arctic sea ice / Re: The 2015 melting season
« on: March 18, 2015, 02:44:02 AM »
Look what defrosted!  I'd been hoping for this camera to open its eyes.

16
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: March 09, 2015, 12:09:10 PM »
That's my conclusion too from looking at recent MODIS images.  The objects with long shadows are concentrated at the Humbolt and extend out from there in long filaments.  I think a contrast stretch would show this well but I don't have time to mess with it at the moment.

17
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 23, 2015, 06:14:16 AM »
Sunrise at Hans Island.

18
The rest / Re: Arctic Café
« on: February 08, 2015, 11:42:25 PM »
Barrow web cam is showing a sunny spring day with blue sky.

19
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: February 07, 2015, 11:26:48 PM »
Wow, I sure didn't expect that.  I really expected to ice in the Kane to be frozen fast for the winter.

20
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 29, 2015, 06:40:08 PM »
Smith Sound looks like the end to me.  Winds were from south and brisk for two days.  They have started to turn now but it looks like they slowed the ice enough to promote arch formation.

I didn't measure accurately but it looks like my maybe-iceberg went just 40 km or so between the 1-26 and 1-28 Sentinal images and is still well upstream of the nascent arch.

But in another day the wind will have filled in stronger from the north and my iceberg, if it is, should be pushing hard to get through.  We'll see how well the arch holds up.

21
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 28, 2015, 10:56:58 PM »
Wind.

22
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 27, 2015, 02:38:17 AM »
A-Team, thanks.  The papers were interesting.  The attached graph from the 2010 paper shows how February is a typical time for ice outflow to drop, so I think arch formation this year isn't overdue at all here in January still.

Tor, thanks for running the numbers.  Yep, ice is still ripping right through the Kane.  A day of light winds wasn't enough to let the passage freeze up and now the northerlies have returned.  I guess I'll go back to watching for a show stopper in the Robeson.

23
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 25, 2015, 06:34:18 PM »
Interesting wind links, Tor, I didn't know those.  But if the wind is determined from cloud tracking, I would expect it may or may not correspond well to surface wind.  I kind of like http://dalriada.sams.ac.uk/aws_hans/ as a surface data point on the Nares.

Incidentally, the weather station is currently reporting that the wind has recently dropped.  So I'll be watching the Kane for arch formation.  From the latest Sentinal images, the channel of briskly moving ice has been narrowing and other ice in the Kane, while not completely stationary, has looked sluggish.  I can imagine that these conditions -- sluggish ice and light winds -- might be conducive to freeze up.

24
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: January 22, 2015, 05:38:19 PM »
Is this an iceberg?  I've been watching this thing for a couple of months now.  I think it came down from the north around the end of October and may have been sitting on the Petermann sill much of the time since.  Today's Sentinal image shows it merging into traffic so it may be interesting to watch it travel down the Nares.

25
Arctic sea ice / Re: Arctic Refreeze Discussion: 2014/2015
« on: January 13, 2015, 07:04:29 AM »
The METOP-1 AVHRR shows major collapse north of the Nares Strait, I do not recall seeing this previously in mid-January.

It's striking, hm?  Some of us have been following this eagerly on the Nares Strait thread.  The discussion there has been great.  I understand that in 2007 there was no arch so would expect it looked similar then.  I also understand that February isn't too late for an arch to form, but arch formation sure doesn't seem imminent.  Meanwhile, as you point out, the ice pack in the Lincoln Sea is going to be pretty loose.  I'm interested to see what effects this might cause if it persists.  Would it affect ice movement in the greater CAB?  Would ice be more mobile or would these conditions perhaps buffer ice pressure that normally drives the Beaufort Gyre, resulting in less movement?  The ice export through the Nares seems startling, but maybe the trans-polar drift exports the same amount of ice whether it can use both the Nares and the Fram or just the Fram.

26
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: December 29, 2014, 07:50:19 PM »
I'm still watching for another arch to form, farther down.  I've only been watching the arctic ice since the sensational losses of 2012 but I've gotten the impression that Smith Sound is historically the typical place for an arch.  The last couple of years we've seen arches more up into the Kane Basin but either way, most of the Nares is then immobilized for the winter.  Our arch in the Lincoln this year looks precarious.  It seems not that uncommon for the thick ice in the Lincoln to get squished around or see big cracking events.  I can imagine either of these collapsing the arch and restarting export.  Last week the arch survived as some cracks ran across the norther Lincoln Sea but didn't spread further south.  This week I'm watching for the weather to maybe increase pressure on the ice and possibly squish it some.  Meanwhile ice is flowing relatively freely down the length of the Nares.  Somehow conditions need to change to slow the (now mostly young) ice enough to let another arch solidify.

27
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: December 29, 2014, 07:15:51 PM »
A curious white glitch in the north suddenly paints the darker thin ice between the thick floes pure white.

... the formation of ice? South of Franklin Ø ...

I interpret that as more of a glint than a glitch.  Sometimes a patch will light up like that in one image and then be back to normal in the next.  See for example http://ocean.dmi.dk/arctic/images/MODIS/Kennedy/20141223s01a.ASAR.jpg where an image stitch seam cuts right across a similar glint south of Franklin.

28
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: November 25, 2014, 08:11:47 PM »
The Nares is one of my favorite places to watch.  Thanks for that animation Wipneus.  I like the images on the DMI site http://ocean.dmi.dk/arctic/lincoln.uk.php (which is back up today after being down for a few days over the weekend.)  And I've gotten a lot out of the comments in the Nares Strait thread here  http://forum.arctic-sea-ice.net/index.php/topic,176.0.html]here [url]http://forum.arctic-sea-ice.net/index.php/topic,176.0.html[/url].  On the DMI site you can access last year's images for comparison and watch last year's "stopper" wedge in the Robeson channel around the first of the year.

29
Oh these are nice.  I've been enjoying the Sentinal images on the DMI site recently but the higher resolution here is impressive.

30
The calves appear to be moving more freely now.  Compare to animations posted over the summer where many of them appeared grounded.

Looking at some of those prior animations now, it looks like maybe the calves weren't exactly stationary but were staying in formation as they moved with the glacier advance.  So maybe they were being pushed over the ground.  Yet something keeps them separated from each other.  I wonder if it is regolith scoured upstream that becomes a moraine now at the end of glacier.

31
Arctic sea ice / Re: Laptev Bite
« on: September 21, 2014, 08:23:22 AM »
I found this nice weekly log of their activities, http://www.awi.de/de/infrastruktur/schiffe/polarstern/wochenberichte/alle_expeditionen/ps_85_87_ark_xxviii/ps87/15_september_2015/  It talks a lot about core samples, but I would expect they do a bunch of other stuff too.  I imagine the interest is just the opportunity to work quickly and easily in the ice-free conditions.

32
Greenland and Arctic Circle / Re: Jøkelbugt / North East Greenland
« on: September 18, 2014, 10:22:42 PM »
Nice clear view of the Belgica Bank today.  Quite a bit of ice is still holding fast!

33
Arctic sea ice / Re: Sep 1963 SIE from Nimbus I satellite data
« on: September 04, 2014, 04:48:01 AM »
There's some news on this at http://cires.colorado.edu/news/press/2014/nimbus.html.

It sounds like new data is up at the NSIDC now.

34
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 02, 2014, 08:30:14 PM »
It is high time for an update of the Fram Strait animation. ...

This animation nicely shows a rather large ice floe passing through the Victoria, just off Franz Josef Land.  This floe has taken much of the summer to edge closer and finally pass through the channel.  It has stayed mostly intact up until now, but today's MODIS images are hinting that it might be breaking up.  I expect it to go "poof" soon.

35
Yesterday the smoke over Michigan caught my eye on the satellite images.  Today when I went outside the sky was gray over Boston.  Oh no, I thought, I know what that is.  A look at current satellite confirms it, smoke from the Canadian fires has pushed over New England now.

36
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: July 22, 2014, 10:38:47 PM »
Ice really is moving north through the Robeson Channel currently.  Clouds over the Nares have made ice watching frustrating lately so I was eagerly awaiting today's radar images on the DMI site.  They're here now, and though maddingly missing data across the Hall basin, reveal interesting ice movement.

If you blink against images from the 19th you see that while ice (including remnants of the sturdy stopper) is lazily floating south through the Kennedy Channel, it is quite clearly moving north through the Robeson!  That should ease the Ikea traffic jam, if we could only see it.

Looking farther up into the Lincoln Sea shows a rip where is ice is moving north on the west side of the sea and south on the east side.  Check your favorite source of surface wind data (I really like earth.nullschool.net) for insight into this.  Brisk winds are blowing straight up the Robeson and west Lincoln Sea driving this ice return.  A little farther south in the Kennedy, winds are not as strong and apparently do not overcome the drag of the current flowing south.

37
Huh.  And now it's working fine.  No idea why it wouldn't have worked for me earlier.  Computers are flaky.

38
:( It didn't animate for me.

39
Those cracks on the southern side look more prominent as well.  Also very interesting in that image is how the melt ponds on the sea ice all all disappeared.  I imagine this is from the ice decompressing following the Nares breakup.

Wouldn't that be pond drainage?

Right.  I'm thinking that as the ice is allowed to expand down the fjord, the "seals" break on the ponds and they drain.

40
Those cracks on the southern side look more prominent as well.  Also very interesting in that image is how the melt ponds on the sea ice all all disappeared.  I imagine this is from the ice decompressing following the Nares breakup.

41
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: July 12, 2014, 07:54:32 AM »
It's difficult to be certain through the clouds, but it looks like the "sturdy stopper" is now sporting some cracks:

http://1.usa.gov/1rfbvk1

Flip to Aqua to see some cracks in the Lincoln Sea also.

Oh, very good catch.  You know, I had spotted the cracks in the Aqua image but didn't bother to try to look past the clouds in the Terra image.  Taking a closer look now, and blinking against images of a few days ago, the ice not only has new cracks but has noticeably bulged to the south.  (Sorry I don't have an animation to show.)  Hopefully we'll get a better look in several hours.

42
Greenland and Arctic Circle / Re: Greenland 2014 Melt Season
« on: July 11, 2014, 06:13:11 AM »
... an odd-looking feature on Greenland's ice sheet, south of Jacobshavn...

A cloud edge?


43
Arctic sea ice / Re: The 2014 Melting Season
« on: July 09, 2014, 10:50:34 PM »
A few clouds around messing up the view today, but nonetheless a long strip of ice has just become detached from northern Greenland:

I saw that too and found it striking.  Then I checked images from around this time last year and saw that the ice edge was similar, making this technically mostly first year ice that has broken off.  Still I would think it is highly compacted and rather thick ice.  It's a lot of volume to be set free.

44
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 29, 2014, 08:40:05 PM »
That's better  :)  What an amazing catastrophe.  I know, it's an annual thing, but it's still awesome.  Neven's Nares breakup special edition should be soon now.  But there's still a little suspense in how long the remaining ice will last.  I think it was last year that an arch just below the Hall Basin hung on for several days before succumbing to the inevitable.  Earlier this week I looked at the little crack that formed at Franklin Island and wondered if the arch it formed would be sturdy.  But nope! today's images show a whole succession of arch-shaped cracks blowing right by it.  It's also fascinating to me that this breakup happens in the "white" ice more than in the "blue" ice.  Somehow I imagine the blue ice softer.  Maybe that's just it.  Maybe it gives a little, while the more brittle ice is forced to crack.

The suspense will shift soon to the Lincoln.  MYI was being lost at an astonishing rate last year before the "sturdy stopper" ended the export season.  Since then there was that big fracturing event in the Lincoln, and most recently polynyas have appeared on either side of the Lincoln.

45
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 29, 2014, 05:35:04 PM »
Final break up is underway:
Gosh, what terrible image!  There must be some problem in the decoding or reconstructing or something.

46
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 28, 2014, 07:30:17 PM »
I think some of the decrease in the Kara in the last few days has been due to wind moving the ice and packing the loose fragments closer together.  In Wipneus's 1-day delta above the decrease along the pack boundary is paired with an increase through the Kara Gate (the narrow strait south of Novaya Zemla.)  This export shows well in the concentration maps above.  Winds seem to be dying now but here's one of nullschool.net's attractive wind maps from yesterday.

47
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 26, 2014, 07:15:37 PM »
The remaining arch this morning struck me as looking like a flying buttress.  Now, we don't expect it to hold back Ellesmere Island from collapsing on Greenland, but if you pick the Humboldt as your frame of reference, maybe Ellesmere does seem to be pressing in?

There's a nice cloud-free view of the Nares from space currently.  A few new small cracks are visible.

48
Don't know the name of the glacier but it's easily seen a bit north of the Jakobshavn.

49
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 22, 2014, 01:24:29 AM »
A little action at Nares Strait:
Yes, I just saw that (and clear as it is, looked at the 7-2-1 image as well.)

I like to speculate about the mechanical forces an ice arch, and one thing I've been wondering is if the Huboldt glacier plays a part.  It's easy to see the ice-water boundary and think of that as the arch, but I wonder in this case if advancement of the glacier doesn't add enough compression to make the "real" arch a broad band stretching from the Humboldt across to Ellesmere.

50
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 19, 2014, 08:14:50 PM »
Whew, sorry for the false alarm, everyone.  Another beginner mistake.  That did seem a rather spectacular way for the breakup to begin, but with occasional ice movement in the Lincoln lately, it did seem possible.

Otherwise, ice has been getting blue around the margins of of Nares but still seems solidly white up and down most of the length, hm?  I try to resist making predictions but I sure like to watch.  It also seems that as the warmup progresses, some patches darken in the radar images.  I make guesses, but I really have no idea what it means.

Pages: [1] 2