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gerontocrat

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Re: The 2020 melting season
« Reply #4950 on: August 16, 2020, 09:47:50 PM »
A different way of looking at the Arctic... from Russia

http://www.aari.ru/main.php?lg=1&id=134
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glennbuck

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Re: The 2020 melting season
« Reply #4951 on: August 16, 2020, 10:07:21 PM »
Still plenty of warm surface air temps coming into the Arctic Ocean on the 21st August, 3.4 C around the North Greenland Coast, Chukchi Sea, 7 C. Northern Passage, 6 C. Franz Josef Land, 4.7 C.
« Last Edit: August 17, 2020, 02:29:02 AM by glennbuck »

glennbuck

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Re: The 2020 melting season
« Reply #4952 on: August 16, 2020, 10:28:14 PM »
Nice view today of the North East Greenland Coast/Greenland Sea.
« Last Edit: August 16, 2020, 10:39:46 PM by glennbuck »

pearscot

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Re: The 2020 melting season
« Reply #4953 on: August 16, 2020, 10:47:30 PM »
I did some quick edits on my phone to enhance the contrast/curves above Greenland:

pls!

uniquorn

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Re: The 2020 melting season
« Reply #4954 on: August 17, 2020, 12:18:29 AM »
The awi amsr2 presentation, currently under development, has been available for 10 days. Here is a preview of CAA ice drift (aka garlic press) using the test version. aug6-15

Paul

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Re: The 2020 melting season
« Reply #4955 on: August 17, 2020, 12:38:21 AM »
EC 12z op run has a possible serious bomb cyclone down to 967 hpa at D9. At D7-9 we might also see a strong dipole line up. The two good things are that this is far out in time and that the potential bomb cyclone is not hitting the most vulnerable parts of Beaufort Sea.
The problem is that both the GFS as the Euro are predicting the same horrible scenario for the end of the month. This could be the final "blow" for the ice if that happens.

Only if the ice pack is diffused(like 2016) it will have an affect but I don't think a medium strength low will have much impact. Its one to keep an eye out because as the PV tries to form, mix that with warm air then the deep low risk does increase as we head closer to September.

At the moment, its fairly slack, what does that small low that is in the ESS at the moment will do in the future? The hints of a dipole are still there on the ECM but it's one of those outputs where we will see alot variability between runs I'll imagine.

Weather dude mentions about temperatures dropping but the cold pools are not all that widespread and it's what you expect at this time of year. I will say though, high pressure over the pole is probably better for the ice now though, decreases the chances of dispersion by quite a fair bit I reckon.

igs

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Re: The 2020 melting season
« Reply #4956 on: August 17, 2020, 12:48:44 AM »
Only if the ice pack is diffused(like 2016) it will have an affect but I don't think a medium strength low will have much impact. Its one to keep an eye out because as the PV tries to form, mix that with warm air then the deep low risk does increase as we head closer to September.

Didn't we have such a low recently and the impact was immense, so how can you say that.

Without a storm of some significant strenght we shall end up second which is most probable, with heavy strom over 2-4 days we shall end up second with a margin and should such a storm hit the right place in the right angle we're still cometing with 2012.

Only because the GAC happend at the beginning of August does neither mean that a similar or nowadays even lesser event can't have a similar impact.

I've seen a few storms predicted that hit first from one side and then from the other which would be bad for the ice and then there remains the possibility of a compacting high over the CAB that would suffice to reach second place with a comfortable margin if not even worse.

Freegrass

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Re: The 2020 melting season
« Reply #4957 on: August 17, 2020, 01:11:30 AM »
Only if the ice pack is diffused(like 2016) it will have an affect but I don't think a medium strength low will have much impact. Its one to keep an eye out because as the PV tries to form, mix that with warm air then the deep low risk does increase as we head closer to September.

Didn't we have such a low recently and the impact was immense, so how can you say that.

Without a storm of some significant strenght we shall end up second which is most probable, with heavy strom over 2-4 days we shall end up second with a margin and should such a storm hit the right place in the right angle we're still cometing with 2012.

Only because the GAC happend at the beginning of August does neither mean that a similar or nowadays even lesser event can't have a similar impact.

I've seen a few storms predicted that hit first from one side and then from the other which would be bad for the ice and then there remains the possibility of a compacting high over the CAB that would suffice to reach second place with a comfortable margin if not even worse.
Wouldn't a strong storm at the end of the melting season bring up warm water and cause a delay in the freezing season?
Now let's pray...

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Jim Hunt

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Re: The 2020 melting season
« Reply #4958 on: August 17, 2020, 01:16:22 AM »
Polarstern seems intent on taking a close look at the North Pole in the near future:
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

HapHazard

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Re: The 2020 melting season
« Reply #4959 on: August 17, 2020, 01:22:59 AM »

oren

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Re: The 2020 melting season
« Reply #4960 on: August 17, 2020, 02:48:31 AM »
A very interesting and important article that was referenced by A-Team and Uniquorn in the Mosaic thread. What the actual melting season looked like.
The first image show the progression that can be seen on Worldview, mostly white to bluish to gray. Click to zoom.
As a reminder, the third image shows the PS floe up close on June 30th.

Quote
Sea Ice Ticker No. 49, 14 August 2020 - The Big Melt

Figure 1: Changes of the MOSAiC ice floe during ~1 month observed with Sentinel-2 satellite images.

Figure 3: A digital thermistor chain unit in the old Central Observatory on 21 July.

When Leg 4 arrived at the MOSAiC floe, summer had already started, and we observed widespread surface melting. On the first walkabouts around the floe, we came across the first melt ponds, a few of which were open, while the others were covered with a thin layer of snow and ice. The snow was already slushy and wet, but still a few tens of centimetres deep. Compared to surrounding ice floes, ours stood out from the rest, thanks to its high abundance of melt ponds (Fig. 1).
 
Since then, air temperatures have been close to or above 0° degrees and the floe began melting from the top, but also from the bottom. The snow disappeared except in heavily ridged areas, where the snow crystals resembled giant jewels. We observed these slow but unstoppable processes with our various tools for measuring the ice thickness.
 
On our transects – regular walks across the floe, always following the same route – we measured ice thickness with the GEM (ground-based electromagnetic sensor)... We recorded a gradual decrease in the average ice thickness: a drop of approximately one metre over the course of July. At the same time, pond depths began increasing, until the first holes appeared in the melt ponds through which the meltwater poured into the ocean below. In some ponds, we recorded spectacular depths of more than 150 cm.
 
While the transect measurements reflect the decrease in thickness, ablation stakes allow us to distinguish between the melting below and melting above. ... We measured an average of ~85cm of ice thinning across our stakes sites from 26 June to 30 July. Surface ablation accounted for seventy-five percent of that thinning, while bottom melting made up the remaining twenty-five percent.
 
The remotely operated underwater vehicle (ROV) “Beast” surveys the ice from below. ... Comparing the maps produced over several dives showed that not all the ice melted at the same speed. Especially the deep keels that extended more than 8 metres into the comparably “warm” ocean were eroding quickly. In some parts of the ridged ice, keel depth decreased by up to 2 metres in just the first 14 days.

Digital thermistor chains (Fig. 3) are another essential tool for measuring changes in ice and snow thickness over time. Over 30 of these units were deployed across MOSAiC’s Central Observatory, which allowed us to monitor the hourly temperature evolution in different ice and snow layers spread out around the floe. Though the data is still being processed, the legs of the DTC unit in the photo (Fig. 4) illustrate the progressive ice surface melting: the tops of the white tubes were initially installed level with the ice surface.
 
In the end, the decreasing thickness, pre-existing weaknesses, and numerous thaw holes in melt ponds made the floe unstable and less able to withstand ocean swell and collisions with surrounding floes. Many cracks appeared, and eventually, our one big floe broke apart into many smaller ones, which will now continue to melt until they disappear completely.






Paul

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Re: The 2020 melting season
« Reply #4961 on: August 17, 2020, 03:27:01 AM »
Only if the ice pack is diffused(like 2016) it will have an affect but I don't think a medium strength low will have much impact. Its one to keep an eye out because as the PV tries to form, mix that with warm air then the deep low risk does increase as we head closer to September.

Didn't we have such a low recently and the impact was immense, so how can you say that.

Without a storm of some significant strenght we shall end up second which is most probable, with heavy strom over 2-4 days we shall end up second with a margin and should such a storm hit the right place in the right angle we're still cometing with 2012.

Only because the GAC happend at the beginning of August does neither mean that a similar or nowadays even lesser event can't have a similar impact.

I've seen a few storms predicted that hit first from one side and then from the other which would be bad for the ice and then there remains the possibility of a compacting high over the CAB that would suffice to reach second place with a comfortable margin if not even worse.

That was in an area that was starting to show signs of diffusion before the low hit. I think we would of seen similar results even without the low although no doubt things have progressed quicker because of it.

The CAB looking at worldview looks reflectively intact if albeit the ice just looks really thin.

wallen

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Re: The 2020 melting season
« Reply #4962 on: August 17, 2020, 05:11:15 AM »
Not sure if it just my system, but Corrective Reflectance 7,2,1 doesn't seem to open up past the East Greenland coast, today.

 I am wondering about the pending Fram export during the freeze season. My understanding is that more sea ice exports during this time, but given there virtual no strong fast ice along the coast to help retard the sea ice as it moves.
But looking at the pitiful condition of the ice above Greenland, I think this would further hinder any slowing of Fram export, till deeper into winter.

oren

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Re: The 2020 melting season
« Reply #4963 on: August 17, 2020, 05:24:02 AM »
...
Fram export winds ceased in mid-May, not displaying a consistent pattern since. Despite the lack of a dramatic storm in the Straits this season, the 'cumulative impact' of moderate but generally non-northerly winds could possibly explain both the lift-off from the CAA, churning of Lincoln Sea ice, and the remarkable deterioration towards the Pole.

Since the ice has not been notably pushed, southerly winds would have needed to bring some mix of sunshine, warm air and overturned warm water acting on dodgier-than-realized ice.  Morris Jesup is not favorably located for katabatic winds off the Greenland summit ridge. No one here has systematically examined online daily records of the automatic weather station there.
...
Following a comment by A-Team on the Mosaic thread, I have compiled temperature statistics for Cape Morris Jesup at the northernmost tip of Greenland, the border between the Lincoln Sea and the Wandel Sea. To my surprise, despite the whole region having the lowest summer ice cover in the satellite record, the temps have been just a bit high compared to the last ten years. 2012, 2016, 2019 and 2015 were all warmer.

I couldn't find a reasonable method to compare the wind statistics though.

https://www.ogimet.com/cgi-bin/gsynres?lang=en&ord=REV&ndays=50&ind=04301&mes=08&day=17&ano=2020

Click to enlarge images.

I’M IN LOVE WITH A RAGER

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Re: The 2020 melting season
« Reply #4964 on: August 17, 2020, 06:00:21 AM »
After seeming to be less visible on yesterday's image, the widespread lower concentration in the CAB quadrant above eastern Greenland appears to have returned on the AMSR2 graphic. Considering that it seems to periodically shift around, but never disappear entirely, I feel like this region will definitely continue to be of great interest through the last few weeks of the melt season and I am very curious to see how it ends up in thickness, concentration, and extent by mid-September. At the moment I really don't know what to expect. HYCOM, SMOS and DMI modelled thickness all seem to suggest there is a large area of <1m ice north of Greenland, so if the region is both thin and low concentration, it might still have a few tricks up its sleeve for us yet.

I’M IN LOVE WITH A RAGER

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Re: The 2020 melting season
« Reply #4965 on: August 17, 2020, 06:04:55 AM »
Here is the more zoomed-in regional AMSR2 product as well. Certainly worth maintaining eyes on IMO

ArcTickTock

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Re: The 2020 melting season
« Reply #4966 on: August 17, 2020, 06:10:09 AM »
We've got a "flash back" with the NSIDC extent, up 63k today

What is the area of the Coronation Gulf in the CAA???  That entire gulf just instantaneously filled up with NSIDC “miracle ice”!
« Last Edit: August 17, 2020, 06:23:00 AM by ArcTickTock »

ArcTickTock

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Re: The 2020 melting season
« Reply #4967 on: August 17, 2020, 06:15:30 AM »
Oh, BTW, it appears the Northwest Passage is open for traffic.  Might have to navigate around some drifting ice north of King William Island.

Alphabet Hotel

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Re: The 2020 melting season
« Reply #4968 on: August 17, 2020, 06:38:30 AM »
Something is definitely going on here


Michael Hauber

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Re: The 2020 melting season
« Reply #4969 on: August 17, 2020, 06:39:06 AM »
Cloud has somewhat cleared to give a reasonable view of the areas in the Chukchi/Beaufort region that have recently lost all ice according to sensors:
Climate change:  Prepare for the worst, hope for the best, expect the middle.

pearscot

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Re: The 2020 melting season
« Reply #4970 on: August 17, 2020, 06:49:07 AM »
Something is definitely going on here

Atlantification pt.2: The Lincoln™ Situation
pls!

ArcTickTock

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Re: The 2020 melting season
« Reply #4971 on: August 17, 2020, 07:08:05 AM »
Something is definitely going on here

Atlantification pt.2: The Lincoln™ Situation

It almost just looks like the entire branch of the North Atlantic Current that flows north through the eastern Fram which used to abruptly turn ENE after passing Svalbard to pass just north of FJL has made a huge shift to the west and is now surfacing, running the northern coast of Greenland and then turning north along the eastern side of the Lomonosov Ridge!  Of course, I could just be imagining things.

JayW

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Re: The 2020 melting season
« Reply #4972 on: August 17, 2020, 07:28:02 AM »
Something is definitely going on here
Some of this is surface wetness from rain.
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Freegrass

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Re: The 2020 melting season
« Reply #4973 on: August 17, 2020, 08:12:23 AM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Now let's pray...

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Jim Hunt

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Re: The 2020 melting season
« Reply #4974 on: August 17, 2020, 09:29:27 AM »
Oh, BTW, it appears the Northwest Passage is open for traffic.

BTW, there is a dedicated Northwest Passage thread:

https://forum.arctic-sea-ice.net/index.php/topic,3208
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

johnm33

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Re: The 2020 melting season
« Reply #4975 on: August 17, 2020, 09:38:31 AM »
Something is definitely going on here
" what i expect is a tidally moderated flow from the Atlantic forcing it's way across N.Greenland and Ellesmere/Axel-Heiberg Is. creating turbulence/vortices which will remove all coastal ice from the shelf. That'll flow into Beaufort and an enhanced flow west from Banks island is likely, and there may be some drawn down Nares but reversal of flows through the CAA. NWPs. So more Atl. waters into both the ESS and Beaufort, but we'll see." from
 Not 100% but I'd call that a definite maybe.

binntho

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Re: The 2020 melting season
« Reply #4976 on: August 17, 2020, 09:57:35 AM »
Something is definitely going on here
" what i expect is a tidally moderated flow from the Atlantic forcing it's way across N.Greenland and Ellesmere/Axel-Heiberg Is. creating turbulence/vortices which will remove all coastal ice from the shelf. That'll flow into Beaufort and an enhanced flow west from Banks island is likely, and there may be some drawn down Nares but reversal of flows through the CAA. NWPs. So more Atl. waters into both the ESS and Beaufort, but we'll see." from
 Not 100% but I'd call that a definite maybe.
John, will you please stop posting nonsense like this. There is no "tidally moderated flow" from the Atlantic "forcing it's way"  anywhere. If you think there is, provide actual evidence.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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oren

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Re: The 2020 melting season
« Reply #4977 on: August 17, 2020, 10:10:16 AM »
To put it in other terms John, as the tide is not much different than years past, this doesn't sound like a sufficient explanation by itself.

wallen

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Re: The 2020 melting season
« Reply #4978 on: August 17, 2020, 10:27:50 AM »
To put it in other terms John, as the tide is not much different than years past, this doesn't sound like a sufficient explanation by itself.

Could it be as simple as a strengthening of the flow from the Atlantic. Causing more warmer water up the Greenland side ?

Neven

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Re: The 2020 melting season
« Reply #4979 on: August 17, 2020, 10:29:51 AM »
I'm not following very closely, but it seems it's just the winds (and lots of weakened ice, of course). As soon as the winds turn, those gaps will close presto.
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BornFromTheVoid

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Re: The 2020 melting season
« Reply #4980 on: August 17, 2020, 10:41:24 AM »
A few items for your morning viewing.

First is the latest concetration map and the previous 3 days ice loss.

2nd is an animation from the N. of Greenland over the last 7 days. With northerly winds the gap is beginning to close. While concentration seems to be dropping, it will need to persist another few days to be sure it's not some artifact. (Larger animation on twitter: https://twitter.com/Icy_Samuel/status/1295278607640788992)
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

johnm33

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Re: The 2020 melting season
« Reply #4981 on: August 17, 2020, 11:24:58 AM »
To put it in other terms John, as the tide is not much different than years past, this doesn't sound like a sufficient explanation by itself.
Certainly not in isolation, but whilst the low persisted the new moon tides enhanced existing currents across the shelfs slope north of Greenland and began the process, then that incoming had to go somewhere so exited via the CAA enhancing currents at depth there. Having observed that i expected more of the same which we seem to have. We also have ideal mslp to enhance flows up onto the Barentz shelf hence flows entering the basins from Franz Victoria trough [@45E] and then a subsurface current illustrated by Ascat through the winter moving towards Fram after crossing Lomonosov by Belov trough are adding to the mix.
It seems to me that the ocean is waking up and since the only forcings on it are barometric changes and tides these are in the early stages of establishing currents.  The winds are not so different from previous years so don't seem like a sufficient explanation either

binntho

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Re: The 2020 melting season
« Reply #4982 on: August 17, 2020, 11:29:36 AM »
... but whilst the low persisted the new moon tides enhanced existing currents across the shelfs slope north of Greenland and began the process, then that incoming had to go somewhere so exited via the CAA enhancing currents at depth there ...
But this is all just free-form fantasy, John. You have no evidence whatsoever for any of your statements, and neither do you have a plausible mechanism for how "new moon tides" can "enhance existing currents".
because a thing is eloquently expressed it should not be taken to be as necessarily true
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binntho

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Re: The 2020 melting season
« Reply #4983 on: August 17, 2020, 11:34:57 AM »
It seems to me that the ocean is waking up and since the only forcings on it are barometric changes and tides these are in the early stages of establishing currents.  The winds are not so different from previous years so don't seem like a sufficient explanation either
"Ocean waking up" ...  the only forcings are "barometric changes" and "tides"?

Everything that is happening in the arctic can be explained with reference to increases in temperature combined with weather and existing ocean currents. There is no need to drag your tidal fixation into it, particularly since you are totally unable to show any evidence for your claims.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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oren

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Re: The 2020 melting season
« Reply #4984 on: August 17, 2020, 11:38:10 AM »
The winds have been different - we had a long-lived anti-cyclone all over the CAB for most of July. This explains all sorts of strange phenomena.
John please take further discussion to the Tides thread.

uniquorn

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Re: The 2020 melting season
« Reply #4985 on: August 17, 2020, 12:42:39 PM »
The WARM Buoy and Side Kick system (see below) was deployed at ICEX 2020 camp station in Beaufort Sea.
I've just stumbled across these moving pictures of ICEX 2020:
A good reminder to take a look at how the jamstec(icex) buoys are drifting. It's a buoys eye view of dispersion in the chukchi. I hesitate to say it, but it looks like more evidence of tidal motion.
jul12-aug16 Click

Static wider view for location.

binntho

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Re: The 2020 melting season
« Reply #4986 on: August 17, 2020, 12:47:46 PM »
I hesitate to say it, but it looks like more evidence of tidal motion.
No need to hesitate! Tidal motion is real, of course, and it's actually very interesting to see it in action. And the small back-and-forth fluctuation obviously has nothing to do with John's musings.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

FishOutofWater

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Re: The 2020 melting season
« Reply #4987 on: August 17, 2020, 12:56:34 PM »
Mercator ocean shows a current at 100m running through the Nares strait and wrapping around the north coast of Greenland. The Coriolis effect turns currents with a northwards component to the right in the NH so the current is very likely a warm current running northeastwards through the Nares strait which then keeps turning right along the continental shelf of northern Greenland. The current maps for 30m and 0m show eddies, complexity and directional ambiguity but I'm confident that there has been some upwelling in areas where the ice has been transported away from the coast.


P-maker

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Re: The 2020 melting season
« Reply #4988 on: August 17, 2020, 12:58:17 PM »
Neven:

Quote
As soon as the winds turn, those gaps will close presto."

John33:

Quote
...the only forcings on it are barometric changes and tides" and "The winds are not so different from previous years"

& binntho:

Quote
Everything that is happening in the arctic can be explained with reference to increases in temperature..."

All, please let's keep an open mind.

This 2018 paper by McFarlin et al. ( https://www.pnas.org/content/115/25/6357 ) came up with a new interpretation of the early Holocene heat anomaly NW of Greenland. They suggested summer temperatures 3-5 C higher than present, mainly driven by astronomical forcing.

This 2007 paper by Nørgaard-Pedersen et al. ( https://doi.org/10.1029/2006PA001283 ) documented two periods in the past, when subarctic foraminifers were abundant in ocean sediments NW of Greenland (Lincoln Sea). Isotopic substage 5a and LIG (5e) also known as the Eemian, may be good analogues for a soon to come "Giant Gap" N of Greenland.

Most likely interpretation is that polynias NW and NE of Greenland "merged" N of Greenland and a direct E- or W-going current of Atlantic origin existed N of Greenland. Several drivers of this W-bound current have been suggested:

1) Offshore (S-ly) winds off the Greenland Icesheet
2) Tides
3) Temperatures

Several additional factors may be at play here:

4) An over-abundance of Atlantic hurricanes may contribute to extreme S-ly winds over Greenland over the next few months
5) The Lomonosov Ridge or the Cape Morris Jesup Rise may play key roles in the rearrangement of current Arctic currents
6) The warming of Laptev and other Siberian Seas may have "forced" the Atlantic current in a W-ly direction

However, the physics involved have not yet been dealt with, and this may require a separate thread in order to not stir this one up. I must admit that I "miss the old days" when one of Neven's ASIB entries led to a broad, informed discussion at a fairly low pace for several days or weeks. At that time, contributors were allowed to think between their posts.

In order to make the connection to our immediate present and near future calamities, this recent paper based on a new version of the Hadley Centre model ( HadGEM3 ) resolving meltponds on the Arctic sea ice ( https://www.sciencedaily.com/releases/2020/08/200810113216.htm ) points to an early ice-free Arctic Ocean already in 2035. Since it is behind a paywall, and not all details in the marine part of the model spectrum are freely available, it would be nice to get a hint of what the currents in the model will look like in about 15 years.
« Last Edit: August 17, 2020, 01:28:39 PM by P-maker »

binntho

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Re: The 2020 melting season
« Reply #4989 on: August 17, 2020, 01:53:01 PM »
Mercator ocean shows a current at 100m running through the Nares strait and wrapping around the north coast of Greenland. The Coriolis effect turns currents with a northwards component to the right in the NH so the current is very likely a warm current running northeastwards through the Nares strait which then keeps turning right along the continental shelf of northern Greenland. The current maps for 30m and 0m show eddies, complexity and directional ambiguity but I'm confident that there has been some upwelling in areas where the ice has been transported away from the coast.
I very much doubt that there is a warm current flowing north through the Nares strait. There is a tidal current in the Nares, but the general flow is of cold water going south. See this paper for more details, "Propagation and Vertical Structure of the Tidal Flow in Nares Strait".

There is apparently a current flowing from the mouth of the Nares north-east along the Greenland coast. I have suggested that this is the northward pulse of the tidal current, similar to what I have experienced alongt he coast of Sicily south of the Messina strait, a narrow and periodic, but at times surprisingly vigorous, current.
« Last Edit: August 17, 2020, 02:01:29 PM by binntho »
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Jim Hunt

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Re: The 2020 melting season
« Reply #4990 on: August 17, 2020, 02:01:51 PM »
In order to make the connection to our immediate present and near future calamities, this recent paper based on a new version of the Hadley Centre model ( HadGEM3 ) resolving meltponds on the Arctic sea ice points to an early ice-free Arctic Ocean already in 2035.

See also:

https://GreatWhiteCon.info/2020/08/past-evidence-supports-complete-loss-of-arctic-sea-ice-by-2035/

Things are much more "low paced" over there!
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Freegrass

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Re: The 2020 melting season
« Reply #4991 on: August 17, 2020, 02:41:01 PM »
Latest Five Day Forecast
Wind @ Surface
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!
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gerontocrat

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Re: The 2020 melting season
« Reply #4992 on: August 17, 2020, 03:17:34 PM »
Mercator ocean shows a current at 100m running through the Nares strait and wrapping around the north coast of Greenland. The Coriolis effect turns currents with a northwards component to the right in the NH so the current is very likely a warm current running northeastwards through the Nares strait which then keeps turning right along the continental shelf of northern Greenland. The current maps for 30m and 0m show eddies, complexity and directional ambiguity but I'm confident that there has been some upwelling in areas where the ice has been transported away from the coast.
I very much doubt that there is a warm current flowing north through the Nares strait. There is a tidal current in the Nares, but the general flow is of cold water going south. See this paper for more details, "Propagation and Vertical Structure of the Tidal Flow in Nares Strait".

There is apparently a current flowing from the mouth of the Nares north-east along the Greenland coast. I have suggested that this is the northward pulse of the tidal current, similar to what I have experienced alongt he coast of Sicily south of the Messina strait, a narrow and periodic, but at times surprisingly vigorous, current.
I am currently reading a paper from 2015 link. Random extracts attached..
My take on it..
Ice Arches matter - none this year?
The main current is heading south, at the western edge when there is landfast ice, on the centreline when ice is mobile or non-existent..
A narrow current heads north.

With global heating+arctic amplification say goodbye to landfast ice for longer periods of the year?

But much better for people who know what they are talking about to comment.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC011091
Modeled ocean circulation in Nares Strait and its dependence on landfast‐ice cover

Quote

Ice conditions typically alternate between landfast and mobile states that are associated with the formation and breakdown of ice arches across Smith Sound and northern Robeson Channel [Kwok et al., 2010]. In years in which neither ice arch forms, such as 2007, ice fluxes roughly 2–3 times those of a typical year have been inferred [Kwok et al., 2010] and modeled [Rasmussen et al., 2010].

The multiyear Canadian Archipelago Throughflow Study [CATS; Münchow and Melling, 2008] maintained a mooring array across southern Kennedy Channel (roughly 80.5°N, Figure 1) from 2003 to 2012.

In the annual mean, flow across most of Kennedy Channel is southward with a vertically averaged magnitude of about 7 cm s−1 on the western side of the channel. On the eastern edge of the channel (south of Franklin Island located at 80.8°N, 66.5°W), a narrow current heads to the north with a depth mean of roughly 4 cm s−1. Rabe et al. [2012] showed that the mean structure of the main southward current is markedly different under landfast and mobile ice conditions, with important implications for seasonal and interannual variability of freshwater transport through the strait.
« Last Edit: August 17, 2020, 03:23:51 PM by gerontocrat »
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Re: The 2020 melting season
« Reply #4993 on: August 17, 2020, 03:26:24 PM »
Only if the ice pack is diffused(like 2016) it will have an affect but I don't think a medium strength low will have much impact. Its one to keep an eye out because as the PV tries to form, mix that with warm air then the deep low risk does increase as we head closer to September.

Didn't we have such a low recently and the impact was immense, so how can you say that.

Without a storm of some significant strenght we shall end up second which is most probable, with heavy strom over 2-4 days we shall end up second with a margin and should such a storm hit the right place in the right angle we're still cometing with 2012.

Only because the GAC happend at the beginning of August does neither mean that a similar or nowadays even lesser event can't have a similar impact.

I've seen a few storms predicted that hit first from one side and then from the other which would be bad for the ice and then there remains the possibility of a compacting high over the CAB that would suffice to reach second place with a comfortable margin if not even worse.

That was in an area that was starting to show signs of diffusion before the low hit. I think we would of seen similar results even without the low although no doubt things have progressed quicker because of it.

The CAB looking at worldview looks reflectively intact if albeit the ice just looks really thin.


I think that we currently see an almost unprecedented amount of diffusion, especially in the beaufort but CAA and NE Greenland as well, hence there is plenty of room where a medium or heavy storm can do his nasty work of destrution.

However you comment is correct, it just implies that this is not or cannot be the case over the next 2-3 weeks which should I interpreted wrong I apologize for.

Have a good day


 :)

glennbuck

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Re: The 2020 melting season
« Reply #4994 on: August 17, 2020, 03:27:14 PM »
Air near-surface temps in the CAB quite high today.
« Last Edit: August 17, 2020, 04:14:48 PM by glennbuck »

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Re: The 2020 melting season
« Reply #4995 on: August 17, 2020, 03:45:04 PM »
Sea Surface Temps in the CAB quite high today.
Those are air temps.

BornFromTheVoid

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Re: The 2020 melting season
« Reply #4996 on: August 17, 2020, 04:22:04 PM »
Projecting based on the previous 20 years melt rates from August 16th, none produce a minimum below 2012. The average melt rate would place 2020 at 3rd lowest, while the slowest melt would result in 7th lowest. 10/20 result in the 2nd lowest minimum on record.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gerontocrat

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Re: The 2020 melting season
« Reply #4997 on: August 17, 2020, 07:26:29 PM »
I attach NICO Sun's AWP cumulative anomaly graph for the High Arctic. https://cryospherecomputing.tk/NRTawp

Not quite a recordbreaker, but close.

With the July high over the Arctic for so long, plus sea ice area at record lows with loads of melt ponds, maybe more heat than usual was actually absorbed by the ocean.

If so, maybe more than usual bottom melt to come + prolongation thereof ?
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Frivolousz21

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Re: The 2020 melting season
« Reply #4998 on: August 17, 2020, 07:59:48 PM »
I haven't been able to post recently cuz I had a new job working 60 to 70 hours a week.

Everything is looking towards a second lowest extent a record low volume and possibly a record-low area but it's going to be close
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marcel_g

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Re: The 2020 melting season
« Reply #4999 on: August 17, 2020, 08:19:36 PM »
I haven't been able to post recently cuz I had a new job working 60 to 70 hours a week.

Everything is looking towards a second lowest extent a record low volume and possibly a record-low area but it's going to be close
Congrats on the new job.

I'm still wondering how much melting is going to happen in the remaining few weeks, while there is still a lot of weak ice to melt, I wonder how much melting will get into the Central Arctic Sea, given A) that the ice above 85N will start to refreeze soon, B) August hasn't had much wind to move the ice around and bring it in contact with warmer saltier water C) the current windy forecasts that Freegrass has been posting show a bit of wind across the ESS and some going out the Fram?

GFS is showing a lot of wind on the Atlantic side about 8-10 days out, but that's not reliable, and wouldn't that be too late to make much of a difference anyway?