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ghoti

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Re: What the Buoys are telling
« Reply #600 on: June 11, 2015, 10:26:13 PM »
http://imb.erdc.dren.mil/2014G.htm indicates it is colocated with O-Buoy.

Siffy

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Re: What the Buoys are telling
« Reply #601 on: June 11, 2015, 10:43:34 PM »
two photos from other threads
Obuoy11 showing beginning of meltpond


obuoy12 after some snowfall
[/img]

It doesn't say explicitly but from lat / long information it looks to me like IMB2014G is colocated with obuoy12 does anybody have information to confirm this? Mind you it doesn't help much to know, top and bottom sounder seem to be out on 2014G

Obuoy 11 is showing some more melt ponding building.

Here is why.





That looks like a huge amount of heat being absorbed.

Andreas T

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Re: What the Buoys are telling
« Reply #602 on: June 11, 2015, 10:50:17 PM »
the wet patches at obuoy12 are getting bigger again too

Andreas T

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Re: What the Buoys are telling
« Reply #603 on: June 12, 2015, 09:11:57 AM »
What time zone do the timestamps on the IMB webcams correspond to?  Given the amount of light at 2015A in the images around 12:00, my guess would be US Pacific, which is the University of Washington's time zone.  Is that right?
I agree with Jim. Obuoys state UTC explicitly on the monitor page.
The remote arctic camera2 at 2015B has updated at 20150612063756. It is 7:45 British summer time at the time I saw this, that makes that time stamp UTC  i.e. Greenwich mean time as well.
Camera1 shows 20150612004826 as the time for its latest picture but of course that could be updating late.

sedziobs

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Re: What the Buoys are telling
« Reply #604 on: June 12, 2015, 03:18:54 PM »
That could be.  2015A (Camera1) is 10 hours behind UTC.  We would expect midnight sun at 10:00 and high noon at 22:00.  If that's the case, then Camera1 is facing NW rather than north.

Andreas T

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Re: What the Buoys are telling
« Reply #605 on: June 13, 2015, 01:27:07 AM »
IMB2015E is getting close to the ice edge heading for Fram strait.
http://1.usa.gov/1B8T6yy
water temperature below the ice has gone from about -1.8 to about -1.5
lets see how long this lasts

Obuoy9 on the other hand is pretty much stopped near north east Greenland
« Last Edit: June 13, 2015, 01:39:46 AM by Andreas T »

Laurent

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Re: What the Buoys are telling
« Reply #606 on: June 13, 2015, 07:29:38 AM »
Obuoy9 is stuck because there is a bottleneck there, the ice more fluid from Swalbard area comes first, it should not be long before there is an acceleration of obuoy9, the part where it does stand is crumbling.
http://obuoy.datatransport.org/monitor#overview/gpstracks

Andreas T

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Re: What the Buoys are telling
« Reply #607 on: June 13, 2015, 12:46:29 PM »
At IMB2015A camera1 shows ice darkening as algae (or sediment?) build up in the melting surface.
air temperatures are up again and sunlight will start to have higher input into that darker ice.
It shows the influence of snow cover. Where surfaces are still white the melt is progressing much more slowly. Also the warming water undercuts ice which is above the waterline.

Rubikscube

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Re: What the Buoys are telling
« Reply #608 on: June 14, 2015, 09:56:51 AM »
2015E which sits north west of Svalbard (but more than 50 km from the ice edge!) is in such warm waters that it could melt out before July.
« Last Edit: June 14, 2015, 05:56:40 PM by Rubikscube »

Andreas T

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Re: What the Buoys are telling
« Reply #609 on: June 14, 2015, 01:33:20 PM »
Obuoy9 is on the move again.
Obuoy12 camera hasn't updated since the 12.6. but shows a surprising dip in temperature below -5. Just shows that delays in the general melting trend are possible.

are you taking distance from Worldview, rubikscube, or are there other ways to measure them?

Rubikscube

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Re: What the Buoys are telling
« Reply #610 on: June 14, 2015, 02:29:10 PM »
are you taking distance from Worldview, rubikscube, or are there other ways to measure them?
Yes, I was using worldview to make that estimate, but I think I mixed up between longitude 1.47 and -1.47  :). The buoy is still about 40 km away from the open ocean, but closer to where one would expect to find such warm waters.

It may be the ice is warming faster around the drill hole where the sensors are, but I would assume that is an effect usually associated with surface melting.

Andreas T

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Re: What the Buoys are telling
« Reply #611 on: June 14, 2015, 05:26:58 PM »
what I see in the preliminary data file downloaded from http://imb.erdc.dren.mil/2015E.htm are temps below the ice going up to -1.1 and then dropping to -1.6 but ice temperature slowly climbing to -2. That looks entirely plausible to me with eddies of warmer saltier water (or warmed surface water) swirling towards the ice floes coming in the opposite direction. But I don't claim more expertise than basic understanding of fluid dynamics.
todays worldview is cloudy but I think your 40km estimate is spot on.



Andreas T

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Re: What the Buoys are telling
« Reply #612 on: June 16, 2015, 09:02:37 AM »
obuoy10 camera hasn't updated for some days now
Obuoy11 is interesting, surface melt had slowed down, now temperatures are above zero in fog. When the camera clears it will be interesting to see the effect this has on the surface.

Carex

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Re: What the Buoys are telling
« Reply #613 on: June 16, 2015, 01:53:21 PM »
At least locally fog is a huge snow eating monster (need another emoticon with huge gnashing teeth)

Tor Bejnar

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Re: What the Buoys are telling
« Reply #614 on: June 16, 2015, 02:43:47 PM »
 ;D
Maybe not the right sentiment (should be :'(), but the teeth are there.   :P
Arctic ice is healthy for children and other living things.

Andreas T

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Re: What the Buoys are telling
« Reply #615 on: June 16, 2015, 10:19:07 PM »
clear view at Obuoy11, looks more white than expected, but the base of the aerial to the right shows this isn't snow deposited. Could it be some frost?
Obuoy12 is back showing increase in the meltponds near and far. 

Rubikscube

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Re: What the Buoys are telling
« Reply #616 on: June 16, 2015, 11:11:12 PM »
I could swear that was fresh snow on O-buoy 11 hadn't it been for that instrument to the right. The sub-zero temperatures correlate with increased winds, maybe its just a thin layer that mostly blew of the areal?

As for 2015E, I find no reason to question your understanding of fluid dynamics, bottom melt has seemingly not been progressing very fast there since my last post, but the ice is steadily warming as it pases through what appears to be swirls of warm and salty waters. Currently, all the sensors there read -1,82C or higher.

Nightvid Cole

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Re: What the Buoys are telling
« Reply #617 on: June 17, 2015, 06:25:04 PM »
NPEO Ablation stakes are showing surface melt between Monday and today at the North Pole station (top image: Monday, bottom image: Today):






Andreas T

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Re: What the Buoys are telling
« Reply #618 on: June 17, 2015, 10:56:04 PM »
The following is a juxtaposition of images from the site of IMB2015B with ice thickness data from its bottom sounder until its ice floe broke and turned it into a free floating weather buoy.
What I find interesting although I don't know how representative it is is that despite the snowfall at the end of may which retarded surface melt by two weeks bottom melt got into its stride at around that time. That was made possible I think by the open sea surface among the shattered floes (low compactness)

Rubikscube

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Re: What the Buoys are telling
« Reply #619 on: June 17, 2015, 10:57:15 PM »
Speaking of ablation stakes; the last one visible on 2015A disappeared without a trace today, could it be that it simply slipped through the ice?

Edit: you have to give it a click.

sedziobs

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Re: What the Buoys are telling
« Reply #620 on: June 17, 2015, 11:08:33 PM »
Looks like it's floating around near the center-right of the latest image.  Probably decided to sunbathe in the toasty 3.62C temps today.

Andreas T

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Re: What the Buoys are telling
« Reply #621 on: June 18, 2015, 12:25:46 AM »
I too think the ablation stake just tipped over, it started to lean. What Is striking about IMB2015A  is the complete lack of bottom melt. Whether this is genuine Iam not sure, but it could be that the "dirtty" ice means not much light (energy) reaches that far.

JayW

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Re: What the Buoys are telling
« Reply #622 on: June 18, 2015, 12:35:38 AM »
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

plinius

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Re: What the Buoys are telling
« Reply #623 on: June 19, 2015, 01:16:16 PM »
Have the impression that the melt pond with obuoy12 is not a melt pond any more.
http://obuoy.datatransport.org/monitor#buoy12/camera
The dark blue would suggest that it has eaten through the ice? (also if you look at their movie, in the last seconds it looks like it broke through and the ice floe suddenly broke/relaxed).

Jim Hunt

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Re: What the Buoys are telling
« Reply #624 on: June 19, 2015, 02:04:47 PM »
The dark blue would suggest that it has eaten through the ice?

Personally I doubt that! However, and as the picture suggests, surface and bottom melt is now apparent at nearby buoy 2014G:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2015-imbs/#2014G-Temp
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

plinius

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Re: What the Buoys are telling
« Reply #625 on: June 19, 2015, 04:10:14 PM »
mh, I would have a trouble to understand how a simple melt pond can flip to such dark a blue (signalling depth) in such short time. Of course happy to stand corrected with that...

Nightvid Cole

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Re: What the Buoys are telling
« Reply #626 on: June 19, 2015, 08:12:27 PM »
Have the impression that the melt pond with obuoy12 is not a melt pond any more.
http://obuoy.datatransport.org/monitor#buoy12/camera
The dark blue would suggest that it has eaten through the ice? (also if you look at their movie, in the last seconds it looks like it broke through and the ice floe suddenly broke/relaxed).

It has not eaten through the ice, rather the ice cracked under it. What I suspect is that the pond is in the same place on the floe as a big melt pond last year. So I would assume that the ice already was very thin under the pond because last year's pond caused the ice to thin underneath (formed a so-called "under-ice melt pond" which is essentially an inverse melt pond formed from melt water pooling under the ice just beneath a melt pond).
« Last Edit: June 19, 2015, 08:18:03 PM by Nightvid Cole »

Jim Hunt

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Re: What the Buoys are telling
« Reply #627 on: June 20, 2015, 02:25:16 PM »
The view from O-Buoy 12 today. It still looks more like a melt pond than sea water to me?
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

plinius

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Re: What the Buoys are telling
« Reply #628 on: June 21, 2015, 01:22:22 PM »
beg to differ ;-)

All I can see in this images is freshly refrozen stuff, fresh snow, and reflections (also right now, so I am not linking it). We'd need to wait till the light is better, though last night we had patches of snow making a better view impossible.

Nightvid Cole

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Re: What the Buoys are telling
« Reply #629 on: June 21, 2015, 04:18:38 PM »
beg to differ ;-)

All I can see in this images is freshly refrozen stuff, fresh snow, and reflections (also right now, so I am not linking it). We'd need to wait till the light is better, though last night we had patches of snow making a better view impossible.

The big melt pond is on the left-hand side of the image, but looks whitish rather than bluish because it is reflecting white cloud layers. Look closely and it even has ripples on it. :)

plinius

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Re: What the Buoys are telling
« Reply #630 on: June 21, 2015, 06:04:43 PM »
I believe having seen snow patches with the sun in the back 10 hours after this image. You simply cannot make your claim on a single photograph. Your ripples can also be snow sticking out. Also there was definitely a similar refreeze on the 13th of June, plus there are plenty of indications for fresh snow in that picture (+ the temperature measurements are in line with refreeze and snow).

Nightvid Cole

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Re: What the Buoys are telling
« Reply #631 on: June 21, 2015, 06:10:31 PM »
I believe having seen snow patches with the sun in the back 10 hours after this image. You simply cannot make your claim on a single photograph. Your ripples can also be snow sticking out. Also there was definitely a similar refreeze on the 13th of June, plus there are plenty of indications for fresh snow in that picture (+ the temperature measurements are in line with refreeze and snow).

The pond is in the same position as in the earlier pictures. I'm not making the claim on a single picture. I can try to show you in a few hours that the pond has expanded if you still can't see it.

plinius

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Re: What the Buoys are telling
« Reply #632 on: June 21, 2015, 10:15:59 PM »
I am sometimes unsure if you properly read other people's posts. I have never doubted that the pond is in the same position, nor were there any uncertainties where it is in the images.
Also, it is not unusual at that position to encounter periods of refreeze. There is a proven such event already in the Movie around the 13th of June.
And of course the melt pond is expanding. Also that has not been doubted by anyone. On the 20th there was cold temperatures paired with 5m/s winds. May be sufficient to freeze a surface, and should be sufficient to keep snow patches in a pond alive.

Nightvid Cole

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Re: What the Buoys are telling
« Reply #633 on: June 21, 2015, 11:47:21 PM »
I am sometimes unsure if you properly read other people's posts. I have never doubted that the pond is in the same position, nor were there any uncertainties where it is in the images.
Also, it is not unusual at that position to encounter periods of refreeze. There is a proven such event already in the Movie around the 13th of June.
And of course the melt pond is expanding. Also that has not been doubted by anyone. On the 20th there was cold temperatures paired with 5m/s winds. May be sufficient to freeze a surface, and should be sufficient to keep snow patches in a pond alive.

So what are you trying to say you think happened?

And P.S. Please don't go down the whole "I'm not sure if you read it" route. In my extensive experience in online forums, this tends to be a precursor to a loss of civility. I realize you may not mean any harm, and so far you have not been ill-mannered, but this sort of comment in general isn't good for a discussion and is probably best avoided (IMO).

If you think I misunderstood something, why not clarify it?


plinius

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Re: What the Buoys are telling
« Reply #634 on: June 22, 2015, 12:50:13 AM »
well, can also come across pretty bossy and slightly unpleasant if someone responds to your post, but as said by you, no harm done I hope. I actually tried digging for their image archives, but could not find them, so suppose we'll have to stall till end June to see how the movie plays it.

My guess was; i) reflection of light, as you point it out. But also ii) some fresh snowfall and clearly sub-zero temperatures. I also believe a saw snowpatches in backlight, corroborating this.
Anyway, we will know more in July.

Nightvid Cole

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Re: What the Buoys are telling
« Reply #635 on: June 22, 2015, 12:54:30 AM »
well, can also come across pretty bossy and slightly unpleasant if someone responds to your post, but as said by you, no harm done I hope. I actually tried digging for their image archives, but could not find them, so suppose we'll have to stall till end June to see how the movie plays it.

My guess was; i) reflection of light, as you point it out. But also ii) some fresh snowfall and clearly sub-zero temperatures. I also believe a saw snowpatches in backlight, corroborating this.
Anyway, we will know more in July.

I think I might have seen a partial glaze-over earlier today, but it only covered a small part of the pond and is gone now. As you say we will know in July.

Yuha

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Re: What the Buoys are telling
« Reply #636 on: June 22, 2015, 10:18:45 AM »
2015A is now floating. In the first image it is still held up by ice. In the second, taken 6 hours later, it is floating in water. The sensors interpret this as a sudden fall of snow.




ghoti

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Re: What the Buoys are telling
« Reply #637 on: June 22, 2015, 04:18:42 PM »
This is why the buoy webcams are so helpful. I wish every buoy had a camera.

Andreas T

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Re: What the Buoys are telling
« Reply #638 on: June 23, 2015, 01:02:14 AM »
North of Greenland a lead is opening. Obuoy9 is a little north of it, its GPS track shows the movement is east rather than north.

Andreas T

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Re: What the Buoys are telling
« Reply #639 on: June 23, 2015, 08:52:31 AM »
IMB2015B is no longer reporting ice thickness because it is no longer sitting in the ice but floating between floes.
The images from camera2 http://ipab.apl.washington.edu/WEB_CAM/USIABP_WEB_CAMERAS.php give an indication that bottom melting is taking place. With shifting floes it is probably not possible to compare accurately and measure change in freeboard but it is clear that it has become significantly less over the last couple of weeks.
What is also visible is the melting taking place at the edges of the floes where sea water undercuts the surface ice which is white enough to absorb less of the incoming sunlight.

Andreas T

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Re: What the Buoys are telling
« Reply #640 on: June 23, 2015, 09:08:04 AM »
at Obuoy9 a lead is becoming visible in the background, but I doubt that it is wide enough to be seen in the resolution of the eosdis images

Nightvid Cole

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Re: What the Buoys are telling
« Reply #641 on: June 23, 2015, 06:28:23 PM »
IMB2015B is no longer reporting ice thickness because it is no longer sitting in the ice but floating between floes.
The images from camera2 http://ipab.apl.washington.edu/WEB_CAM/USIABP_WEB_CAMERAS.php give an indication that bottom melting is taking place. With shifting floes it is probably not possible to compare accurately and measure change in freeboard but it is clear that it has become significantly less over the last couple of weeks.
What is also visible is the melting taking place at the edges of the floes where sea water undercuts the surface ice which is white enough to absorb less of the incoming sunlight.

Also, the ablation stake shows roughly 6.3 strips exposed, cf. about 3.3 strips exposed just after the big snowstorm in late May. Since each strip is 10cm, this means the surface has fallen by 30cm. The Buoy data showed ~23 cm of snow cover just after that snowstorm, so a loss of 30cm from the surface since then implies that approximately 7cm of ice surface melt has occurred as of that last image.

plinius

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Re: What the Buoys are telling
« Reply #642 on: June 23, 2015, 08:18:34 PM »
In principle we could try using the ablation stakes to calculate the freeboard.
Suggestion for an equation:
f = (s_f / s_a)*(d_f/d_a) * corr
where s_f = image size of freeboard
s_a = image size of ablation stake (segment)
d_f = distance to the freeboard
d_a = distance to the ablation stake
corr is an angle correction factor, as the angle under which we see the freeboard changes with distance. The correction vanishes (i.e. becomes 1) if we see the freeboard behind the ablation stake.

Now we just need the distance to the ablation stake and the height of the camera. Any ideas? (though in principle we could solve that by measurement if we have a shadow of the camera towards the ablation stake at two different times of the year...

Nightvid Cole

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Re: What the Buoys are telling
« Reply #643 on: June 24, 2015, 12:14:45 AM »
In principle we could try using the ablation stakes to calculate the freeboard.
Suggestion for an equation:
f = (s_f / s_a)*(d_f/d_a) * corr
where s_f = image size of freeboard
s_a = image size of ablation stake (segment)
d_f = distance to the freeboard
d_a = distance to the ablation stake
corr is an angle correction factor, as the angle under which we see the freeboard changes with distance. The correction vanishes (i.e. becomes 1) if we see the freeboard behind the ablation stake.

Now we just need the distance to the ablation stake and the height of the camera. Any ideas? (though in principle we could solve that by measurement if we have a shadow of the camera towards the ablation stake at two different times of the year...

One could go back to an earlier image with TWO ablation stakes at different distances, and then based on the ratio of apparent (angular) strip sizes, one could relate the ice surface distance from the camera lens to the position on the image, assuming all ice surfaces are at the same height. Then one can interpolate to figure out the distance ratio between the ablation stake and the ice "ledge" of the next floe over, across the water. From this the height (freeboard) could be determined.

Laurent

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Re: What the Buoys are telling
« Reply #644 on: June 25, 2015, 12:00:59 AM »
Obuoy 12 is near open water ! (I think)

Andreas T

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Re: What the Buoys are telling
« Reply #645 on: June 25, 2015, 12:22:23 AM »
IMB2015E seems to be at the ice edge (not sure about lat /long and eosdis image taken at the same time)
I put the pink dot into http://1.usa.gov/1KaUL7U at Buoy 2015E: Pos: 79.53 N, 0.84 E

Andreas T

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Re: What the Buoys are telling
« Reply #646 on: June 25, 2015, 08:40:13 AM »
major change of scenery at Obuoy9. I wish I'd saved yesterdays image of an increased ridge.
Reading latitude and longitude from the graph is a bit crude, if it is given somewhere as figures I havn't found it.
http://obuoy.datatransport.org/monitor#buoy9/gps
I read it as 82.4 / -15.4
see for yourself http://1.usa.gov/1fDCFjN

Sonia

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Re: What the Buoys are telling
« Reply #647 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

helorime

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Re: What the Buoys are telling
« Reply #648 on: June 25, 2015, 11:11:54 PM »
The floe behind the one that obuoy 9 is on was detached quite a while ago, looking at the movie.  The ridge appears to have occurred when that floe moved away and then bashed back in and slid or turned against the edge of the bouy's floe.

Having said that, I suspect that 9's floe is going to fall apart soon. al the groozes between the camera and the edge appear to be deepening and melting.  I suspect they are cracks that will fracture all the way through.
Any sufficiently advanced technology is indistinguishable from magic.

plinius

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Re: What the Buoys are telling
« Reply #649 on: June 25, 2015, 11:37:49 PM »
by the way - what happened to the cams of 2015A, B?
Not even the links on greatwhitecon.info to them work any more.