the craic was good in 2009 .. :) .. b.c.Do you have pics?
sorry,no .. Worldview doesthe craic was good in 2009 .. :) .. b.c.Do you have pics?
I've seen open water just north of the CAA several times, and north of Greenland last year, but having a nearly continuous stretch of open water along the entire North American continent, and for as long a period of time this year, is unprecedented, I believe. Polynyas that recur in certain locations are often named, such as the North Water Polynya (https://en.wikipedia.org/wiki/North_Water_Polynya). A 'full' list of Canadian polynyas [plus some inAlaska, Greenland and eastern Russia] (http://maps.canadiangeographic.ca/canadas-polynyas/) .
Should this become a feature, I've proposed calling it the NAC: North American Crack. Of course we could call it McCAG: Mega-crack - Canadian Arctic/Greenland: this doesn't 'look' like any other abbreviation... Movement of ice along this boundary, of course, happens 'all' the time. What is less usual is for the ice to pull away (and melt) along most of this boundary at one time, so maybe the NACP: North American Coastal Polynya.
The Canadian list (http://maps.canadiangeographic.ca/canadas-polynyas/) of polynyas identifies the location of un-named "major shore lead polynyas", including one along the entire North American continent. So maybe the NASLP: North American Shore Lead Polynya.
See more discussion of polynya in Wikipedia (https://en.wikipedia.org/wiki/Polynya), Encyclopedia Britannica (https://www.britannica.com/science/polynya) and elsewhere.
[I share my opinions and you choose!]
I think le' crack is a big deal as a leverage point for wind.I don't understand what you mean... if the wind pushes steadily the pack toward Fram, the natural tendency of the ice will be to be steered by Coriolis force to the right of the winds, and close whatever gap there is between the ice and CAA/Greenland.
My BOE vision involves a couple of weeks of steady late season 30+ knot winds pushing the pack toward Fram.
We're set in a few days to at least get a glimpse of what that would look like. Theoretically, it could still happen this year. Who knows what the weather lottery will produce?
OK that may be true. Maybe it's a new feature enhanced by the very weak ice over there compared to pre-2010sThink on it as more the effect than the cause ...
Yet I am unable to see the potential effects a frequent reappearance can have. Not saying it CAB have...
OK that may be true. Maybe it's a new feature enhanced by the very weak ice over there compared to pre-2010scould enhance ssts in the region, where thick ice is supposed to be, keeping volume down, and changing the safe ice reduit.
Yet I am unable to see the potential effects a frequent reappearance can have. Not saying it CAB have...
I sure hope so!OK that may be true. Maybe it's a new feature enhanced by the very weak ice over there compared to pre-2010sThink on it as more the effect than the cause ...
Yet I am unable to see the potential effects a frequent reappearance can have. Not saying it CAB have...
I don't see it however as a feature that survives during winter. That is obvious for every one?
OK that may be true. Maybe it's a new feature enhanced by the very weak ice over there compared to pre-2010scould enhance ssts in the region, where thick ice is supposed to be, keeping volume down, and changing the safe ice reduit.
Yet I am unable to see the potential effects a frequent reappearance can have. Not saying it CAB have...
It might mean another change of paradigm in the arctic, which is one of the reasons why I opened this thread, to compile data to know whether this is the case, I have only been following the arctic for a couple of years, so I am only really aware of the north Greenland crack late summer last year.
A shore lead (or coastal lead) is an oceanographic term for a waterway opening between pack ice and shore. While the gap of water may be as narrow as a tide crack if closed by wind or currents, it can be as wide as 1,000 feet (300 m). Its formation can be influenced by tidal action, or subsurface conditions, such as current and ocean floor.[2] Commonly, a shore lead is navigable by surface vessels.[3]
An opening ("lead") between pack ice and fast ice is referred to as a flaw lead.
Aslan - on the topic of benches, the crack actually offers an explanation that doesn't require a full melt out of the basin. Factor in post melt elastic rebound and you have a working theory for how they got there.I'm a bit suspicious here - I don't think a crack of 10 to 20 km, even occurring every year, can explain beach formation. Waves inshore would be very small and insignificant, espcecally since the crack seems to form mainly when offshore winds are strong and persistent.
Agree 10-20 is not sufficient. 100-200 would be.Aslan - on the topic of benches, the crack actually offers an explanation that doesn't require a full melt out of the basin. Factor in post melt elastic rebound and you have a working theory for how they got there.I'm a bit suspicious here - I don't think a crack of 10 to 20 km, even occurring every year, can explain beach formation. Waves inshore would be very small and insignificant, espcecally since the crack seems to form mainly when offshore winds are strong and persistent.
The beach ridges described in the literature above seem quite substantial, indicating a large wave fetch in onshore winds.
Agree 10-20 is not sufficient. 100-200 would be.The shortest distance between Svalbard and Greenland is 300 km, the Lincoln sea is about 200 km wide in the middle, and the distance from Greenland to the geographic North Pole is just over 400 km.
And it is not looking like we will need a BOE for beach ridging over this caps.
The crack is wider going east to the open water NE of Greenland.And it is not looking like we will need a BOE for beach ridging over this caps.
But I think we do - I don't think there are any realistic scenarios where you can have so much open ocean north of Greenland / CAA with continuous incoming wave action for long enough periods without what is effectively a BOE.
The "crack" or whatever we should call it is too narrow, too shortlived, and most importantly, it is dependent on offshore winds so there will be no long-fetch waves capable of creating beach ridges.
According to the 7/30 imagery, it appears as though (within reason and for hypothetical purposes) save for one section, it is almost possible to sail around Greenland. I'm not sure if I've ever known this to be possible. Depending on how July unfolds, I wonder if this will completely open up. I'm inclined to say it is, given the fact that the crack continues to expand north and the open water will be absorbing more heat. Either way, this is the single most notable formation of this season.The next step, which also seems to be closer than I can remember seeing it, would be for the main body of remaining Arctic Sea Ice to completely detach from any coastal land, so that it would be possible to circumnavigate the sea ice, without also circumnavigating land.
Pearscot .. is that area or extent ? b.c.
Pearscot .. is that area or extent ? b.c.
I think pearscot meant the open water that is neither area nor extent but open water.
Hope that I'm not wrong but cant's see another meaning at the moment ;)
sorry philopek .. it was an attempt at humour .. b.c.
Pearscot .. is that area or extent ? b.c.add emoticon :)
Aslan, the polynya in Lincoln is not caused due to export through Nares. It's caused by winds blowing north. No ice was exported through Nares for months.
Check this post for a GIF showing it. >> https://forum.arctic-sea-ice.net/index.php/topic,176.msg224602.html#msg224602
Blumenkraft,
Every year in the freezing season, the volume of the Arctic sea surface expands by roughly 10 percent (due to the fact that density of sea ice is lover than that of sea water). If everything (including air pressure and sea level) remains constant, something will have to give in. . . .
Abstract
[1] This study examined the 1979–2004 volume and freshwater fluxes through the Canadian Arctic Archipelago (CAA) and into the Labrador Sea using a high resolution (∼9 km) coupled ice‐ocean model of the pan‐Arctic region to provide a reference, compare with limited observational estimates, and investigate control mechanisms of this exchange. The 26‐year mean volume and freshwater fluxes through Nares Strait were 0.77 Sv ± 0.17 Sv and 10.38 mSv ± 1.67 mSv respectively, while those through Lancaster Sound amounted to 0.76 Sv ± 0.12 Sv and 48.45 mSv ± 7.83 mSv respectively. The 26‐year mean volume and freshwater fluxes through Davis Strait were 1.55 Sv ± 0.29 Sv and 62.66 mSv ± 11.67 mSv while the modeled Fram Strait branch provided very little (∼2%) freshwater into the Labrador Sea compared to the total CAA input. Compared to available observations, the model provides reasonable volume and freshwater fluxes, as well as sea ice thickness and concentration in the CAA. In Nares Strait and Lancaster Sound, volume flux anomalies were controlled by the sea surface height (SSH) gradient anomalies along the straits and freshwater anomalies were highly correlated with the volume anomalies. At least half of the variance in the time series of SSH gradient anomaly was due to SSH anomalies in northern Baffin Bay. The West Greenland Current (WGC) exhibits seasonality, with cross shelf flow (into the Labrador Sea) peaking in January/February/March, while reducing the northward flow across eastern Davis Strait. We hypothesize that the eddy‐reduced northward flow of WGC results in the lower volume and SSH in Baffin Bay. This maximizes the SSH gradients between the Arctic Ocean and Baffin Bay, leading to maximum winter volume fluxes through Nares Strait and Lancaster Sound. Model limitations include the insufficient spatial resolution of atmospheric forcing (especially to account for the effects of local topography), the representation of river runoff into Hudson Bay and coastal buoyancy currents, low mobility of modeled ice, and incomplete depiction of ice arching. Many of these issues are expected to be resolved with increased model grid cell resolution, improved sea ice and ocean models and more realistic atmospheric forcing.
The big question is if the mega crack will happen again next year and so on. The ice being young does not help but if the reason is changed currents (or weaknesses only recently showing) that will change the story for the future.It also happened on 2018. Maybe not as big on CAA, but surely important north of Greenland.
A much more mobile central ice pack can go anywhere in a bad year.
The big question is if the mega crack will happen again next year and so on. The ice being young does not help but if the reason is changed currents (or weaknesses only recently showing) that will change the story for the future.It also happened on 2018. Maybe not as big on CAA, but surely important north of Greenland.
A much more mobile central ice pack can go anywhere in a bad year.
<SNIPPED>unwary swimmer/diver pretty far out. As the ice is 90% underwater, somewhere near the shore the outbound forces exceed the cohesion of the ice and the crack develops. Strong winds and currents may counteract, of course, but I'd be surprised if this does not become a regular feature of the Arctic now.
<SNIPPED>unwary swimmer/diver pretty far out. As the ice is 90% underwater, somewhere near the shore the outbound forces exceed the cohesion of the ice and the crack develops. Strong winds and currents may counteract, of course, but I'd be surprised if this does not become a regular feature of the Arctic now.
Good point for consideration.
I assume you mean something of the linked kind.
https://en.wikipedia.org/wiki/Rip_current
Blumenkraft,
Every year in the freezing season, the volume of the Arctic sea surface expands by roughly 10 percent (due to the fact that density of sea ice is lover than that of sea water). If everything (including air pressure and sea level) remains constant, something will have to give in. . . .
I don't think that's how the physics works. Certainly Nares and Fram surface currents are more robustly southward in winter than summer. But not, I think, because sea water is freezing. Sea ice displaces its *weight* and not its volume.
Just as the water level in a glass of ice water doesn't change as the ice melts, neither does it change if ice forms in the glass. Thus winter freezing of sea water into sea ice doesn't create any net change in forces of flow (all other changes being equal, which they never are in actuality).
I don't have an explanation for the observed seasonal flow patterns, but I'm pretty sure volume of ice formation isn't it.
full moon?
... could be waves ...
^^ you are correct, that was just fog and as of today the water remains open.
Sometimes a picture is worth a thousand words, so I won't say much.
Imagine what this will look like in 1 month(!)
^^ you are correct, that was just fog and as of today the water remains open.
Sometimes a picture is worth a thousand words, so I won't say much.
Imagine what this will look like in 1 month(!)
It's an interesting hole but in terms of what it may look like in 1 months time then I would not be surprised if its covered with ice again, its not temperature related why the hole is there, its down to the fact we actually got some fast(or at least quite resilient) ice blocking the nares strait so basically when the winds was blowing in the right direction, the looser ice seperated itself from the fast ice hence the hole.
There was a lift-off of the ice East of Alert around to the Nares enterance . It can be seen best on Worldview atm as you zoom in @ 50km/50ml a.. as you zoom closer the frame changes to showing cracking but the departure from shore is no longer clear .As it happened. Click to run.
Lincoln is an amazing zone of shear , disintergration and melting of what looked like the safest ice in the Arctic only 2 weeks ago .
+++ It's now gettin' ground up like salt in situ ! b.c.
Thanks JayW .. the moment has been lost now from Worldview .. but you have captured it beautifully .. bcThere is also a rapid and significant darkening of the ice picked up by the visible bands, likely due to warming air descending of the landmass and blowing over the ice. Shows up in AMSR2.
RAMMB stuck again?Appears that way, I fired over a email just now. Hopefully it helps.
The crack must have gone ;)
But wait, there's more. Now that the rest of the imagery was cached from Worldview you can see the extent to which the entire pack is both mobile and fractured
But wait, there's more. Now that the rest of the imagery was cached from Worldview you can see the extent to which the entire pack is both mobile and fractured
Interesting new feature with Pikachu - looks rather large.
The surprised Pikachu face
But wait, there's more. Now that the rest of the imagery was cached from Worldview you can see the extent to which the entire pack is both mobile and fractured
Interesting new feature with Pikachu - looks rather large.
The surprised Pikachu face is how I felt when I made that. At a loss for words and just like: is this reality right now??
The surprised Pikachu face
Wait, one does not simply bring up Pikachu face without making it a propper meme!
But wait, there's more. Now that the rest of the imagery was cached from Worldview you can see the extent to which the entire pack is both mobile and fractured
Interesting new feature with Pikachu - looks rather large.
The surprised Pikachu face is how I felt when I made that. At a loss for words and just like: is this reality right now??
For uniquorn, these are all the images that were available.No time stamps on wolrdview so rammb adds more info. Coastal winds at princess thyra island were 40km/h at 1000hPa, only 21km/h at Ellesmere Is. That both lift off's happened at the same time could just be coincidence. There wasn't a large tide at Alert.
Second is just east of Nansen sound. Lots of areas breaking up the CAA
Love watching these eddies.
Needs click.
Westward motion is slowing. That floe must have landed gently on the tip of Axel Heilberg.
jul19-29
The one shaped like a boat, I assume you mean? I've been watching that, too. It now seems like the island is taking a bit of a bite out of the floe, maybe not so gently.
As nice as it is to have WorldView, what I'd like here is WorldHear, so I can find out what it sounds like for a 20km piece of ice to bounce into an even bigger rock.
A brief peek through the clouds of the eddies north of Ellesmere Island.That's a lot of eddies. The development awi amsr2 view, aug6-15
Monthly update from the Polar Science Center:How does PIOMAS see thicker than normal ice on the north coast of Ellesmere when the AMSR2 shows a lack of land fast ice at same location for August 2020? One of them has to be wrong.QuoteAugust 2020 Monthly Update(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpsc.apl.uw.edu%2Fwordpress%2Fwp-content%2Fuploads%2Fschweiger%2Fice_volume%2FBPIOMAS_ThicknessAnomalyCurrent.png&hash=e7157bf29f2adda140c9d0006442ab66)
<snip>
Ice thickness anomalies for August 2020 relative to 2011-2018 (Fig 6) continue the pattern that has emerged over the winter, spring and shows relatively thin ice along the Russian Coast and thicker than normal in the Eastern Beaufort and the along the Canadian Archipelago.
amsr2-uhh, jul21-sep6