What the Buoys are telling

[Andreas T]

This paper http://www.iup.uni-bremen.de/seaice/amsredata/modis/sea_ice_papers_database/ponds_in_situ_meas/Fetterer_Untersteiner_1998.pdf helped me to understand the processes of meltponds better.
What you see at NPEO is deepening of meltponds rather than widening and increased porosity of the ice lowering the water level. Imb2015D shows that some of the ice is still a little below -2C but the paper quoted above finds that water can travel horizontally to drain where there are cracks or the ice is thinner.

[ghoti]

The O-Buoy 9 movie has been updated up to July 13. Really great footage of ice roaring by and the spinning of the floe the buoy is on. At least from the part where I started at (June 25) til the end.

http://obuoy.datatransport.org/monitor#buoy9/movie

[jdallen]

The O-Buoy 9 movie has been updated up to July 13. Really great footage of ice roaring by and the spinning of the floe the buoy is on. At least from the part where I started at (June 25) til the end.

http://obuoy.datatransport.org/monitor#buoy9/movie

What that movie shows us is that there's more open water than not at that location... North of 80.

[seaicesailor]

I was wondering if someone might offer an explanation for what is happening at ITP WHOI 87 ?
Friv pointed it out a couple days ago but there is about 20-25 meters of surface water at about
-.8 C and it has persisted for about ten days. Bouy 87 is located over deep basin waters almost
300 kilometers offshore so upwelling seems not likely. Salinity was up for a few days but now it is fresh but unusually warm water beneath the ice. Thoughts?

http://www.whoi.edu/page.do?pid=137336

FWIW a big hole of open water has appeared close to the location of this buoy. Melting thread:

http://forum.arctic-sea-ice.net/index.php/topic,1149.msg56775.html#msg56775

[Andreas T]

the position of ITP87 is from the 12th 07 135.06W 75.35 and the image from 10th, closest clear view
so this isn't an exact match but not much movement took place around that time as far as I can tell.

[Andreas T]

Again not the same day and not the same location but what I hope it shows is how warm the open water is towards the coast and that the large gaps between floes also reach surface temperatures above freezing.
http://1.usa.gov/1CDcJ2v

[seaicesailor]

the position of ITP87 is from the 12th 07 135.06W 75.35 and the image from 10th, closest clear view
so this isn't an exact match but not much movement took place around that time as far as I can tell.

The moth that uni-bremen shows might be that clear area at the left of the image, where the floe in the center and the other smaller ones might have melted out, and maybe the hole increased in size ...

Maybe it is just coincidence but it called my attention. I dont understand much the kind of data these buoys collect and are displayed

[Andreas T]

My earlier post about IMB2015E was premature it seems. Rather than breaking out it seems to have slipped down within the hole in the ice where it sits. Now there is some further movement.
It is not right at the edge of the ice but the swirls of warmer and saltier water are visible in worldview.

[Andreas T]

: ghoti  July 14, 2015, 11:29:36 PM

The O-Buoy 9 movie has been updated up to July 13. Really great footage of ice roaring by and the spinning of the floe the buoy is on. At least from the part where I started at (June 25) til the end.

http://obuoy.datatransport.org/monitor#buoy9/movie




What that movie shows us is that there's more open water than not at that location... North of 80.

this is my choice as the likely position of Obuoy9 yesterday. Current GPS location from the graph is not very precise but this floe matches the movement and turning of the buoy position as far as I can tell.
BTW why is the azimuth given at 90 deg when the camera is looking south? It took me a while to work this out from sun pos.
....
edit: image not shown in quote, don't know how to fix that

yesterdays image  shows that floe getting closer to the relatively warm waters of the northeast polynya
http://1.usa.gov/1K9R0l2

[Bruce Steele]

ITP 85 is about 5 degrees west of ITP 87 and it too has gotten into some -.8 surface water.
# 87 hasn't updated in a couple days so nothing new there.

http://www.whoi.edu/page.do?pid=139056

[Andreas T]

Iapb camera2 http://iabp.apl.washington.edu/WEB_CAM/camera2/ deserves an update:
the floe it sits on keeps getting smaller and looks soggy. The floes nearby are lying lower in the water than they used to be, I don't think a good estimate of their freeboard can be made the floe edges are undercut by warming sea water but indicating that bottom melt has made progress.
IMB2015B floating free nearby reports water temperatures of up to -0.45 C at its lowest sensor, T31 2.7m below the surface. (most recent reading -0.8 coincidently equal to what ITP87 sees elsewhere at greater depth)

[oren]

Iapb camera2 http://iabp.apl.washington.edu/WEB_CAM/camera2/ deserves an update:
the floe it sits on keeps getting smaller and looks soggy. The floes nearby are lying lower in the water than they used to be, I don't think a good estimate of their freeboard can be made the floe edges are undercut by warming sea water but indicating that bottom melt has made progress.
IMB2015B floating free nearby reports water temperatures of up to -0.45 C at its lowest sensor, T31 2.7m below the surface. (most recent reading -0.8 coincidently equal to what ITP87 sees elsewhere at greater depth)

If my layman's eye is not misleading me, the floe on the right bottom can also be seen below the water line, and seems eaten from all sides by the seawater, so that its bottom is spherical rather than flat as I would imagine.
Apologies if this is all nonsense.

[Andreas T]

A later image http://iabp.apl.washington.edu/WEB_CAM/camera2/usiabp_camera2_20150716223630.jpg
 which shows it from a different angle helps to interpret what is seen there. This floe was part of a ridge where floes pushed together and produced a layered and angled jumble of broken bits. You are right to expect a flat bottom where a floe is formed by gradual freezing downwards from an initial thin surface layer. This agglomeration can have any shape and will orient itself in whatever position its buoyancy and mass distribution balances. Melting will also have altered its shape.

edit: wrong image linked

[Andreas T]

this floe at camera2 shows what ice looks like when it is getting thin.
I think the ice is now porous from molten brine channels and therefore translucent when low in the water and wet but white when the the drained brine has been replaced by air.  The image shows that the surface of the floe on which the camera stands is still well clear of the water but the reduced density of the ice above the waterline gives an exaggerated impression of its overall thickness.

[andy_t_roo]

this floe at camera2 shows what ice looks like when it is getting thin.
I think the ice is now porous from molten brine channels and therefore translucent when low in the water and wet but white when the the drained brine has been replaced by air.  The image shows that the surface of the floe on which the camera stands is still well clear of the water but the reduced density of the ice above the waterline gives an exaggerated impression of its overall thickness.

and this picture also highlights the difficulty of separating melt ponds from ice area; this picture shows that the circular holes in the ice appear to be true holes, so represent a decrease in area; does anyone have a satellite picture of this area, and what it looks like compared to the earlier times when we could see that they were melt ponds instead?

[Andreas T]

The only satellite images I can access are the MODIS images on https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor%28hidden%29,MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-07-19&v=-5242880,-2580480,5242880,2580480
their maximum resolution is 250m which means the whole floe makes only part of a single pixel.
worldview gives lat / long coordinates for your pointer so you can locate the position easily in the image

To find the position of the camera I use the lat/long coordinates from IMB2015B (via http://imb.erdc.dren.mil/buoysum.htm) which was colocated see upthread or Jims websitehttp://greatwhitecon.info/resources/arctic-sea-ice-images/summer-2015-images/
older images of the camera buoy can be found at http://iabp.apl.washington.edu/WEB_CAM/camera2/

I prefer that list because it doesn't download all images which makes it quicker if you know what you are looking for.

[oren]

Am I the only one that can't access the O-Buoy site? 
http://obuoy.datatransport.org/

[Andreas T]

Am I the only one that can't access the O-Buoy site? 
[url]/http://obuoy.datatransport.org/[url]

I was going to ask the same question, withdrawal symptoms are setting in
from worldview the floe where I locate Obuoy9 has travelled over 20km south and is past the northeast corner of greenland into water which band 31 colour temperature calls over 275K. Plenty of more ice piling in behind so I don't  expect it to go in a blink, but I'd love to watch the on board footage.

[Peter Ellis]

and this picture also highlights the difficulty of separating melt ponds from ice area; this picture shows that the circular holes in the ice appear to be true holes, so represent a decrease in area; does anyone have a satellite picture of this area, and what it looks like compared to the earlier times when we could see that they were melt ponds instead?

Considering that the entire field of view of the webcam is a small fraction of a single pixel in the satellite images, they won't help.

[Nightvid Cole]

this floe at camera2 shows what ice looks like when it is getting thin.
I think the ice is now porous from molten brine channels and therefore translucent when low in the water and wet but white when the the drained brine has been replaced by air.  The image shows that the surface of the floe on which the camera stands is still well clear of the water but the reduced density of the ice above the waterline gives an exaggerated impression of its overall thickness.

This is an amazing image!!!

Look in the sky, close to the horizon. You can see subtle lighter and darker regions.

This phenomenon is known as blink, sky blink, ice blink, or sometimes water sky blink. It is caused by reflection of light from areas with a lot of ice and not from open water.

It is very interesting in part because it gives us a sense of what the ice looks like on a spatial scale of a few km, rather than the mere meters we can get from the direct view of the surface.

It is apparent that the ice concentration in that region, out to a few kilometers, is ~50%.

[Rubikscube]

OBuoy 10 is back! That is after being absent for more than a month, and the surroundings look very different compared to the last picture from 12th June (last frame in the movie). NPEO cams also show heavily surface melting during past 48 hours, the volume loss should be significant, but with no recorded bottom melt there is no way what so ever this part of the ice pack will melt out before it goes down the Farm Strait come winter.

[Bruce Steele]

http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1149.0;attach=18484;image

Jim Hunt posted this temperature graph for IMB 2014 I  earlier today. ITP 85 is co-located with
IMB 2014 I and ITP 85 is the only ITP in the Beaufort still sending profiles. Both ITP 87 and ITP 86 quit sending profiles a week ago when they encountered strong surface warming. ITP 85 has encountered similar -.8 surface water now so we will see how long it keeps transmitting. I still maintain these are not normal profiles. Going back through " completed missions " there are some similar temperatures but they don't start at the surface. I think it's unusual to have warm fresh water lenses extending to 20 meters. Alot of heat over a very large area it seems.

   http://www.whoi.edu/page.do?pid=139056

[Bruce Steele]

Also co-located with ITP 85 is this micro-cat with a sensor at 6 meters. Chart clearly shows -.8 fresh water lens at 6 meters, the ITP shows it down to about 20 meters.

http://www.whoi.edu/page.do?pid=139056

[Andreas T]

OBuoy 10 is back! That is after being absent for more than a month, and the surroundings look very different compared to the last picture from 12th June (last frame in the movie). NPEO cams also show heavily surface melting during past 48 hours, the volume loss should be significant, but with no recorded bottom melt there is no way what so ever this part of the ice pack will melt out before it goes down the Farm Strait come winter.

hooray for the four Obuoys being back!
Jim shows temperature profile for 2015D which shows ice temp below melting point so I agree bottom melt hasn't started.
Obuoy9 has now entered the fram strait and shows increased melting,
If the water level in the meltpond near the camera and the channel across the image show freeboard of the floe (which is likely) it has become thinner as well as smaller. As I have said before, it is in relatively warm water now and bottom melt should be fairly strong.

PS 0buoy10 has turned to the left and now shows more buoys. azimuth, pitch and roll don't show any movement which stands out from previous behaviour, but it could be that the part of the floe it stands on has separated from the rest.

[Rubikscube]

PS 0buoy10 has turned to the left and now shows more buoys. azimuth, pitch and roll don't show any movement which stands out from previous behaviour, but it could be that the part of the floe it stands on has separated from the rest.

It looks rather implausible that the camera and buoys are separated. I can't find any cracks and would expect them to disappear out of view pretty quickly. My guess would be that the ice has melted around the camera so it floats around in a hole. The same seems to be happening at O-buoy 11 as well.

I find it pretty amazing that 2015b cam is still standing though. Barely any ice is left in its view now.

[ghoti]

6 hours later 2015b has a view with quite a bit of ice again. So that would suggest it is twirling around right at the edge of the marginal ice zone providing views of both open water and melting ice.

[Andreas T]

we don't have the actual position of the camera as far as I know, but using 2015Bs position (not updated since 17th July) it probably is where I placed the pointer in worldview.
Not at the margin but there are large areas of openwater about and shifting around
with the Obuoy cameras we get an indication of where the camera is pointing from the azimuth but here we don't know iwhether the floe on which the camera sits is turning about.

The ice around there is getting pretty low in the water and the floe with the camera on is getting darker i.e.wetter too.

The worldview is from the 19th but is giving a close enough idea of the situation.

[ghoti]

The movie for Obuoy 10 has been updated.

http://obuoy.datatransport.org/monitor#buoy10/movie

The rapid rotation of the buoy with the camera relative to the rest of the ice is very clear in the last couple of weeks of the movie. You can jump to near the end of the movie to see the recent images.

[Andreas T]

That convinces me that it is indeed swivelling in the hole in which it was positioned. I hope it will give us a view of the directions we haven't seen yet, a view of IMB2013F would be nice. The movement seems to be driven by changing wind directions
What is odd is that it seems to show two profilers and what is the buoy it was looking at for the last two years It has similarities with an Obuoy, with solar panels above a buoyant body. Does someone have information?

[Andreas T]

Obuoy9 is floating around in the north east polynya, its speed displayed in the GPS data shows a strong tidal pattern.
Melting is showing clearly visible effects. I can't identify the floe from its shape on Worldview anymore and the edge is moving towards the camera. Bottom melt seems also to be progressing. Near the camera a darker, deeper area has appeared in the meltpond which until now has looked very shallow.
I hope we can see how that progresses it this closeup view.
PS the surface has become whiter yesterday, and more uniform which looks to me like a thin dusting of snow. A reminder perhaps that July is nearing its end and surface temperatures can go down as well as up.

[helorime]

PS the surface has become whiter yesterday, and more uniform which looks to me like a thin dusting of snow. A reminder perhaps that July is nearing its end and surface temperatures can go down as well as up.

Indeed Greenland has been the one very cold spot in recent days.

[Bruce Steele]

The last ITP buoy (#85) in the Beaufort has stopped giving profiles so within a week of when # 81 hit warm surface waters (-. we lost # 87, 86, and finally 85 to similar melt conditions. So from the evidence of the ITP data it appears the whole Beaufort gyre has warm surface waters to 20 meters.
Bottom melt in the Beaufort should continue for quite  awhile with this mass of warm fresh surface water.

[Andreas T]

iapb camera2  shows a quite different scenery from recently. It has been a while since I have seen ice with that much freeboard from that place. It is also so close to the camera that I wonder whether the camera has swung round and we see the floe which it is / was sitting on. Lets see what happens next.

[ghoti]

Several of the Obuoy movies were updated to include July 27th. I am impressed by the extremely mobile ice around Obuoy 9. Also the difference between Obuoy 10 and 11 is striking. The movies show 10's camera spinning in place while 11's shows that the camera is stable on the floe but the entire floe is spinning.

http://obuoy.datatransport.org/monitor#buoy10/movie

http://obuoy.datatransport.org/monitor#buoy11/movie

Jump to the last minute of each of these to see the latest conditions.

[seaicesailor]

iapb camera2  shows a quite different scenery from recently. It has been a while since I have seen ice with that much freeboard from that place. It is also so close to the camera that I wonder whether the camera has swung round and we see the floe which it is / was sitting on. Lets see what happens next.

Allow me one question, since I never understood freeboard facts very well (freeboard being the height of the gap between ice surface and water surface, ..., right?)

Does this mean that melt ponds are "sinking"? or is there an implication on ice thickness? Meaning, is the ice floating and its surface is much higher than expected because it is thicker than expected?

Well, those are three or four questions 
Sorry  If I could get even one answer . . . 

[Andreas T]

Yes freeboard is the height of the floe surface above the water. This obviously depends on the density of the ice and its thickness. The tricky bit is that the density of the ice is a combination of the density of the actual ice crystals and the concentrated brine trapped between them when the ice formed.
When the ice becomes warmer in the next summer this brine melts ice crystals around it and if it connects with other trapped brine it can form drainage pores which let it seep out of the ice. Ice which was visibly cleared of snow in Obuoy images becomes white and snowlike in appearance in later images because these pores as brine drains out are filled with air. the part of the ice below the water line stays soaked with water, but the salty brine is replaced by meltwater from the surface, this is the process which makes old ice less salty.
Another process which drains water from the surface are cracks and drainage channels which run over the surface to the edge of the floe.
Once the ice has become warm and porous enough  (and ponds warm the ice beneath them because they let in sunlight through the reduced albedo)water in a pond can't be at a higher level than the surrounding sea water.

Some of this is based on what I have read in various places for example here http://www.iup.uni-bremen.de/seaice/amsredata/modis/sea_ice_papers_database/ponds_in_situ_meas/Fetterer_Untersteiner_1998.pdf
part of it is based on observing photos from Obuoys etc  (google image search is useful)

My comment about the freeboard in the camera2 image is based on this: To have a high freeboard the ice below the waterline must have enough buoancy to support the weight of the ice above the water. It must be thick to have a high freeboard. Cryosat uses that principle to measure ice thickness. But I would have to know the weight (density) of the stuff above the waterline to get the calculation right. E.g. if some of this stuff is snow of low density (not likely at this time of the year) or porous ice (not sure how porous this would be) it would seem thicker than it actually is, but it can't be as thin as some of the floes which barely rise above the waterline. How much thicker I don't know.

[Peter Ellis]

I think you'd need a nearby ablation stake to have any chance of guesstimating the freeboard.  Otherwise you're left trying to measure something that's at an unknown distance to the camera, at an unknown angle of elevation, etc.  Eyeballing these things, especially with the fisheye lenses used on many buoys, is next to impossible.

[Andreas T]

Several of the Obuoy movies were updated to include July 27th. I am impressed by the extremely mobile ice around Obuoy 9. Also the difference between Obuoy 10 and 11 is striking. The movies show 10's camera spinning in place while 11's shows that the camera is stable on the floe but the entire floe is spinning.

http://obuoy.datatransport.org/monitor#buoy10/movie

http://obuoy.datatransport.org/monitor#buoy11/movie


Jump to the last minute of each of these to see the latest conditions.

edit: managed to insert my comment into the quote by mistake, sorry Ghoti

The floe with Obuoy9 on it was pretty mobile too, rotating as well at moving in swerving motion driven by tides. Interesting how its movement echoes the movement of Obuoy4 in a previous season

[seaicesailor]

Thank you Andreas, for your time to make that nice explanation. I think I get much better idea. 

[Andreas T]

Meanwhile IMB2015E http://imb.erdc.dren.mil/2015E.htm further into the fram strait to the south and east, shows top and bottom sounder looking at the same surface, i.e. no ice. No clear view on worldview today

[Andreas T]

The floe at obuoy9 http://obuoy.datatransport.org/monitor#buoy9/camera has broken up along an old crack it seems just missing the camera position.

[Rubikscube]

It seems someone pulled the plug at Obuoy11, attached below is the most recent pic from today together with the last frame of the Obuoy movie (from 27th July).

[Rubikscube]

Mayor developments at Obuoy12 as well, there is no doubt that the melt pond discussed earlier is no longer a meltpond, but a crack/lead. Lots of movement and open water popping up everywhere, but no updates in its movie as of yet.

[Bruce Steele]

ITP 85 is back and still showing some-.  to -1 fresh surface water that extends most of the way
the Pacific summer water at about 50 meters.
 http://www.whoi.edu/page.do?pid=139056
 
Looking forward to JimHunts IMB 2014 I update on Aug. 1
http://greatwhitecon.info/resources/ice-mass-balance-buoys/summer-2015-imbs/

[vigilius]

Watching Obuoy 9 with interest, what happens when it actually goes for a swim? Will the camera continue to function? Will the Norsk folks retreive/recycle? (Have been wanting to ask these questions, just found this thread.) Thanks.

[Andreas T]

http://www.o-buoy.org/?p=363
shows what happened to a previous bouy.
The news section of that site says

Two O-Buoys will be deployed this 2015 fall in the Beaufort Gyre from the CCGS Louis St. Laurent by Wes Halfacre (Purdue U.) and two more in the E. Siberian Sea from the I/B Kapitan Dranitsyn  or Akademik Fedorov by Carlton Rauschenberg (Bigelow Laboratory). Three of the buoys are new ones, while the fourth one was previously deployed as OB-8 in the Beaufort; now ready to go again. These will be the last deployments with the currently funded project. The data should stream for 1-2 years. As always, O-Buoy data and images can be found in the ACADIS data portal.

Stay tuned for real time updates this coming fall!

[vigilius]

Thanks, Andreas, I find myself checking these things three times a day, #9 especially, which I suppose I will miss. (Amazing that they can run so long- just solar and battery?)

[Andreas T]

maybe we should have a collection for refurbishing of Obuoy9 if it gets picked up
it does seem to be floating free, no more ice visible near the camera. Looking at azimuth, pitch and roll is interesting. It made a fast turn (azimuth) after midday on the 29th but changed pitch and roll sharply later, nearer midnight UTC possibly suggesting an impact with another floe with later a reduction in floe size making it less stable?
I am in part trying to "read" this data to learn how to interpret the other buoys
Obuoy10 looks about as unstable as Obuoy9 but Obuoy12 shows increased turning motion but still not much rolling and pitching. I take this as sitting on a floe of reduced size, As Rubikscube spotted the former meltpond on the left now shows shifting ice.

PS obuoy10 has shown snowfall for a while now and it looks to me like this snow floating in the water as a layer of slush, near the floes a bit thicker and whiter in places.

[helorime]

And then o-buoy 9 met up with a thicker floe and you can't tell that it ws free before.  The movie is pretty up-to date so you can watch it happening.

[vigilius]

Well, this is just sort of smacking me in the head three hours later, yup this is 9:01 AM. (#9, what are you up to?) I had sort of been hoping this buoy would stay in some ice in the Fram, give me a read on Fram export after all the prognosticating I read over on the melting thread. I am trying to correlate this with the UNi Bremen map, it looks to me like we are sort of halfway across that big gap in the ice off the northeast of Greenland, 80N, 10W.