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Neven

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Re: The 2017 melting season
« Reply #2000 on: June 13, 2017, 10:40:51 PM »
ECMWF is now pointing more seriously to a medium-sized/strong cyclone, emerging a couple of days from now. Combined with some high pressure on the American side of the Arctic, this should make for a somewhat stronger Dipole than yesterday's forecast showed.

The 979 hPa, if reached, won't be as low as we saw during August last year when a GAC-like cyclone noted 968 and then 971 hPa. And the potential pressure gradient of 42 hPa doesn't come close to the 63-64 hPa we saw during last year's Mega-Dipole.

But still, this is June, not August, and it should keep things on the move.

Below the 6-day ECMWF forecast as presented by Tropical Tidbits:
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Quantum

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Re: The 2017 melting season
« Reply #2001 on: June 13, 2017, 11:26:51 PM »
The ECM12Z seems better for ice retention than the 0Z which had the low move further south and undergo stronger cyclogenesis from presumably the horizontal temperature gradients. If the storm is weaker than projected and moves further west then it isn't such a bad situation for the arctic. A dipole is far from ideal but at least there isn't any obvious blowtorch weather.

JayW

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Re: The 2017 melting season
« Reply #2002 on: June 14, 2017, 01:05:03 AM »
Good view yesterday of Alaska looking into the beaufort. Still some snow cover on the extreme northern coast. Assuming it melts out this week that will still be a good week or two later than many recent years. Lakes and ponds on the land are likely to stay frozen for several days yet which can only be a good thing as it modifies air masses moving over them.

That large crack in the fast ice is located close to Utqiagvik and might become visible in the webcam there as open water if  the crack widens or if additional fissures open up.

There she goes.

57 hour loop

Imagery courtesy of the University of Alaska at Fairbanks
http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images
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Tigertown

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Re: The 2017 melting season
« Reply #2003 on: June 14, 2017, 01:15:08 AM »
@JayW
Not only do you see the fast ice breaking off, but look at all the smaller floes getting pushed out to open water to be melted sooner.

JayW

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Re: The 2017 melting season
« Reply #2004 on: June 14, 2017, 01:49:45 AM »
@JayW
Not only do you see the fast ice breaking off, but look at all the smaller floes getting pushed out to open water to be melted sooner.

I'm no expert, but I feel like surface water (melt ponds)+ sunlight  = melting ice

Open water + strong winds (storms) = destruction of ice

I make the distinction because I feel like they are different ways of melting sea ice.

I'm not sure what is worse for ice, melt ponds or open water. I guess it depends on what type of weather is affecting what type of sea ice.   
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magnamentis

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Re: The 2017 melting season
« Reply #2005 on: June 14, 2017, 02:12:05 AM »
*melt pond thought experiment*

<Don't quote long quotes in their entirety, especially if they're off-topic, the scrolling is off-putting; N.>
there is 1 fact to which i agree, nothing is totally certain 😉

as to the rest of your assumption, i disagree, especially to the "sealing" part, it just does not sound right to me, future events and analyzes will show, let's wait and see 😎
« Last Edit: June 14, 2017, 06:37:47 AM by Neven »
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Tigertown

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Re: The 2017 melting season
« Reply #2006 on: June 14, 2017, 05:07:32 AM »
The 11th, 12th, and 13th. The Beaufort opens up a little more, but the area close to the New Siberian Islands and the Kara Sea are maybe the most impressive.
CLICK IMAGE Zoom is recommended

Tigertown

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Re: The 2017 melting season
« Reply #2007 on: June 14, 2017, 06:06:03 AM »
Here is a closer look at the opening close to the New Siberian Islands. A few clouds are in the way, but you can still see the open water expanding. Apparently insolation is starting to get the upper hand.
CLICK IMAGE 12th-14th

Lord M Vader

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Re: The 2017 melting season
« Reply #2008 on: June 14, 2017, 06:41:53 AM »
T-town: add a 980 hpa cyclone over that area and we should have a bigger Laptev hole in a couple of days. As well as more compaction!

Tigertown

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Re: The 2017 melting season
« Reply #2009 on: June 14, 2017, 06:58:53 AM »
In the meantime  surface winds there are as high as 6oC and will go higher over the next 24 hours. If the cyclone develops as expected, it will pull massive amounts of even warmer air from the shore, particularly on the 16th. Then it is forecast to cool and strengthen on the 17th. We will see how close reality will be to the forecast.

Lord M Vader

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Re: The 2017 melting season
« Reply #2010 on: June 14, 2017, 07:15:38 AM »
Guys, GFS 00z op run came in with a 969 hpa june cyclone(!) Have there been a sub 970 hpa cyclone in June, Neven?

Neven

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Re: The 2017 melting season
« Reply #2011 on: June 14, 2017, 07:29:23 AM »
Guys, GFS 00z op run came in with a 969 hpa june cyclone(!) Have there been a sub 970 hpa cyclone in June, Neven?

You mean the forecast for +96 hrs? Hmm, that's not too far out, D4...

I don't believe I have seen a cyclone go that low (pressure-wise) in June, no.

Let's wait for the ECMWF forecast, as I believe it's more reliable than GFS.
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Ice Shieldz

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Re: The 2017 melting season
« Reply #2012 on: June 14, 2017, 07:42:42 AM »
In 72hrs (21:00 UTC 6/16/2017) the GFS has a powerful low drawing in 50km/h+ winds and 2C temps right over the New Siberian Islands' region that Tigertown commented upon.

Lord M Vader

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Re: The 2017 melting season
« Reply #2013 on: June 14, 2017, 07:53:02 AM »
Well, yeah. D4 is not too far away. And yes, t should be extremely interesting to see what the usually more reliable ECMWF 00z op run says. We should know in about 45 minutes!

Oooh!! I just discovered that the GFS 00z run develops an unusually Cape Verde cyclone at D4. Should be a very weird event as such TCs usually don't show up until the end of July.

jdallen

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Re: The 2017 melting season
« Reply #2014 on: June 14, 2017, 08:18:38 AM »
Well, yeah. D4 is not too far away. And yes, t should be extremely interesting to see what the usually more reliable ECMWF 00z op run says. We should know in about 45 minutes!

Oooh!! I just discovered that the GFS 00z run develops an unusually Cape Verde cyclone at D4. Should be a very weird event as such TCs usually don't show up until the end of July.
I'm holding out for the 48-72hr outlooks before getting too excited.

Even so, even a modest blow is going to present serious difficulty for the Laptev, Kara and Barentsz ice; those last two very specifically because of how late the Kara froze over, and how hot the Barentsz is under the ice forced into it from the CAB.

A good blow will turn the Kara into slush, and pull enormous heat up to the surface of the Barentsz via Ekman pumping.  This is could give us a clear demonstration of why the ice's lack of mechanical strength is a problem;  all that Barentsz ice is highly mobile and will neither keep the wind from stirring up the water nor be able to resist it itself.

Personally, I think the N. Atlantic heat previously transported into the Arctic is going to be this years 500KG gorilla lurking in the weeds waiting for the right moment to leap.  There's no way to predict when or if that will happen, but the stage is set for it to do exactly that if we get early and frequent storms roaring up to the Barentsz out of the North Atlantic. 1-1.5C temp increase from depth could tear 5CM/day off of the ice.  As we are starting with little more than a meter across most of that, the implications are self explanatory.

Addendum:  There's a certain amount of excitement over the high 2M temps - 2-6C - showing up over the basin.  The greatest impact of that might be to reduce snow burden on the ice and modify albedo in ways we don't want it to go.  Admittedly, quantity has its own quality, and with sufficient heat - consistently 5-10C above freezing - the ice would be affected directly.

That said, the real heavy lifting in the melt season is still going to rely on insolation and imported ocean heat. Surface air temps are a sideshow.
« Last Edit: June 14, 2017, 08:25:44 AM by jdallen »
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Lord M Vader

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Re: The 2017 melting season
« Reply #2015 on: June 14, 2017, 08:23:35 AM »
ECMWF 00z op run has the cyclone down to 978 hpa at D4. At D5 the pressure is 980 hpa. This cyclone should clearly be labelled as a "Big MAC" :)

Rob Dekker

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Re: The 2017 melting season
« Reply #2016 on: June 14, 2017, 08:28:12 AM »
The Siberian land at the edge of that predicted cyclone is still covered with snow :



It seems to me that not much heat can be pulled in by that cyclone until that snow disappears...

Cid_Yama

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Re: The 2017 melting season
« Reply #2017 on: June 14, 2017, 08:38:42 AM »
And?

Lord M Vader

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Re: The 2017 melting season
« Reply #2018 on: June 14, 2017, 08:41:05 AM »
Rob Dekker: maybe not, but the first cyclone may eventually be followed by another 978 hpa cyclone over the Kara Sea at D7. In tandem with all this, the Beaufort high might rebuilding itself from D6. The second cyclone should have much better opportunities to muscle up the snow cover.

Rob Dekker

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Re: The 2017 melting season
« Reply #2019 on: June 14, 2017, 09:28:27 AM »
LMV, let us hope that the land snow cover buffers Arctic melting long enough to offset the record low ice volume in the Arctic.

JayW

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Re: The 2017 melting season
« Reply #2020 on: June 14, 2017, 09:47:56 AM »
One week loop of June 6-13, Alaska at bottom center.

Imagery courtesy of the University of Alaska at Fairbanks

http://feeder.gina.alaska.edu
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Often Distant

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Re: The 2017 melting season
« Reply #2021 on: June 14, 2017, 10:13:38 AM »
Ready to go?

jplotinus

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Re: The 2017 melting season
« Reply #2022 on: June 14, 2017, 01:19:21 PM »
Good view yesterday of Alaska looking into the beaufort. Still some snow cover on the extreme northern coast. Assuming it melts out this week that will still be a good week or two later than many recent years. Lakes and ponds on the land are likely to stay frozen for several days yet which can only be a good thing as it modifies air masses moving over them.

That large crack in the fast ice is located close to Utqiagvik and might become visible in the webcam there as open water if  the crack widens or if additional fissures open up.

There she goes.

57 hour loop

Imagery courtesy of the University of Alaska at Fairbanks
http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images

Webcam view:


F.Tnioli

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Re: The 2017 melting season
« Reply #2023 on: June 14, 2017, 01:41:17 PM »
...
Personally, I think the N. Atlantic heat previously transported into the Arctic is going to be this years 500KG gorilla lurking in the weeds waiting for the right moment to leap.  There's no way to predict when or if that will happen, but the stage is set for it to do exactly that if we get early and frequent storms roaring up to the Barentsz out of the North Atlantic. 1-1.5C temp increase from depth could tear 5CM/day off of the ice.  As we are starting with little more than a meter across most of that, the implications are self explanatory.
...
Very well put. Thanks for posting it!

We can't predict with certainty if we'll get such storms this season, yes. Yet i guess that both long-term trend of GHGs everywhere (crawling up) and this year's unusually many and unusually strong local storms mid-latitude (so far) - are among reasons to think that probability of seeing such storms this year is higher than ever.

Further, i suspect that "extended" snow cover in places like Siberia is further increasing chances of relatively strong storms forming up: large areas of unusually high albedo "this part" of the picture (producing quite cold air masses as a result, not much IR radiation producied by the surface there) - vs large areas of unusually warm air masses "that part" of the picture. Sooner or later they'll clash into some pretty strong winds, right?

BornFromTheVoid

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Re: The 2017 melting season
« Reply #2024 on: June 14, 2017, 04:02:37 PM »
When looking at the potential upcoming depression in the Arctic, in order to assess how much damage it might do we need to look at more than just the central pressure. The surrounding pressure systems matter too.

Last year's Arctic cyclone was surrounded by high pressure systems, with pressure >1025hPa over the Beaufort sea and Greenland, and a large >1020hPa region over the Barents sea during the stormy period. Coupled with the deep depressions in the eastern Arctic, this created a steep pressure gradient which you need to generate the wind and waves that are damaging to the sea ice.

On the other hand, the forecasted cyclone this month isn't surrounded by any strong high pressure systems. There's weak low pressure system over Scandinavia, pretty neutral pressures over Greenland and a shallow high pressure over the Beaufort sea.
This type of set up is very unlikely to cause much damage, it might in fact be better for ice preservation as it's carrying somewhat cool air and more cloud over the central pack.




marcel_g

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Re: The 2017 melting season
« Reply #2025 on: June 14, 2017, 04:03:24 PM »

there is 1 fact to which i agree, nothing is totally certain 😉

as to the rest of your assumption, i disagree, especially to the "sealing" part, it just does not sound right to me, future events and analyzes will show, let's wait and see 😎

Ok, let's wait and see.  8)

It is possible that the generally younger thinner ice behaves differently than the older thicker ice, so melt ponding behaviour might be different, but I'm not certain that it has. And this year, it might very well happen that the thin ice succumbs to open water + wave action + bottom melt even if there isn't a build up of meltponds + albedo drop + insolation.

F.Tnioli

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Re: The 2017 melting season
« Reply #2026 on: June 14, 2017, 04:20:03 PM »
BornFromTheVoid - very much so; i don't see dramatically strong winds associated with this now-expected low-pressure coming in, either. My previous post was intended for "what comes next" after this depression would come and go. Several pages ago, we had some talk about "five lows" stable system seemingly forming up, and there were mentions about potential stability of the setup (with a strong big high in the middle). Now it seems things are not going that way (to me, at least). I feel that Arctic's athmosphere is now in state of fluid change, if not to say "chaos". Winds and temps are changing back and forth in many places quite often, from what i can see. What will come out of all that, - might be the gorilla mentioned above, or might be weeds will flourish and the gorilla won't see no prey to jump on. Nothing's really certain, even Neven &Co have the hardest time to make any significant prediction in terms of minimums this season.

If i'm not oh too much mistaken with what i just said, then all we can do for now is to formulate some "edge" possibilities, some extreme cases, in a try to designate what would be the limits of the season "in the end". Apart from the usual and very interesting "current events reporting and discussion", that is - the latter being bread and butter of the topic, and as such being always welcome.

And while i'm at it:

I want to thank all the posters who bring in pictures, data and observations about current and short-term model predictions into the topic. You are the best, gentlemen! You are ones who make this topic so relevant and so interesting to read. Thank you all, very very much.

Tigertown

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Re: The 2017 melting season
« Reply #2027 on: June 14, 2017, 04:30:20 PM »
The Siberian land at the edge of that predicted cyclone is still covered with snow :



It seems to me that not much heat can be pulled in by that cyclone until that snow disappears...
The mass of air that will be pulled from on the 16th is from the surface up to over a kilometer in height and will reach temperatures up to 16oC+. Plenty of heat energy for both snow and ice.
« Last Edit: June 15, 2017, 12:24:34 AM by Tigertown »

subgeometer

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Re: The 2017 melting season
« Reply #2028 on: June 14, 2017, 04:42:08 PM »

I believe in the experiment the fissures sealed after the third melt, the first two times the melt water drained away, more slowly the second time.

Thanks. That makes sense and is believable. However, if whatever caused the cracks and fissures  from the beginning causes new ones, then the process resets. If it had been waves vs thin ice, the waves will probably win in long run, as they seem to be reaching deeper into the Arctic now.

Also there are no 100km floes in areas with any dispersal, maybe some 50km in the Beaufort sea, with the odd 10-20km solid floe  in sea of mush elsewhere

Ice Shieldz

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Re: The 2017 melting season
« Reply #2029 on: June 14, 2017, 06:34:33 PM »
It's true that the forecasted inland and surrounding surface pressures aren't that high, but the low is deep enough to create high winds that if verified would likely lead to significant damage and melt. The following is 60 & 84 hour ECMWF surface wind forecast via WindyTV.

RoxTheGeologist

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Re: The 2017 melting season
« Reply #2030 on: June 14, 2017, 07:21:52 PM »
T-town: add a 980 hpa cyclone over that area and we should have a bigger Laptev hole in a couple of days. As well as more compaction!

And cause mixing of deeper Atlantic water over the shelf.

A-Team

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Re: The 2017 melting season
« Reply #2031 on: June 14, 2017, 07:28:21 PM »
Numerous posts on our forums have sought to infer from electromagnetic theory (or just plain intuition) how sunlight ought to interact with sea ice and the water underneath, the issue being the distribution of heat from absorbed light -- a principal driver of the melt season -- along the snow-ice-water column. However those notions do not capture the incredible complexity actually observed in field campaigns. Those in turn are necessarily limited by logistics in areal scope and season.

The N-ICE2015 expedition ran from winter to late spring, whereas almost all previous field data relates to summer (as modestly instrumented unattended winter buoys soon fail or start reporting questionable numbers). N-ICE2015 observed an unprecedented event in late May at 80-81ºN, a very substantial phytoplankton bloom 80 km north of the ice edge. The growth was local, not advected in by Atlantic Waters but perhaps seeded from elsewhere.

The primary species involved, haptophyte algae Phaeocystis pouchetii, is not part of the more familiar ice-underside pennate diatom community and their blooms. Diatoms deplete silicic acid in the upper 50m in building their cell walls (frustules), not observed here.

Being beneath a snow-covered surface ice, the Phaeocystis bloom could not be detected even under leads, much less quantitated, by satellite (segmentation: 1st image)  Snow-covered thick ice transmitted only 1% of incident photosynthetically appropriate solar energy to the underlying water column, compared to 20% for refrozen leads created by the frequent ice divergence events in the oft-dodgy ice north of Svalbard. Melt ponds are not applicable light availability in May as snowmelt only began in early Jun

(Provided skies are clear, large blooms in open water do show up well in WorldView. JayW posted about a bloom already in the Aleutians; last August, massive and persistent blooms covered the north Barents.)

The complex mix of species in these blooms must be determined by sampling; they are never monocultures nor do species proportions remain static over the course of a bloom.The one studied here was comprised of 104 taxa of protistic plankton at 5m depth: diatoms, dinoflagellates, ciliates, prasinophytes, cryptophytes, choanoflagellates, flagellates, chlorophytes and euglenozoa, dominated by the  prymnesiophyte Phaeocystis.

As the Arctic Ocean enters a new era of predominantly first-year ice, one might expect more sunlight would reach photosynthetic organisms at wavelengths relevant to chlorphyll capabilities, even prior to melt pond season. The resulting growth in the upper ten meters would then effectively capture this light, putting the resultant heat in a more favorable position to bottom-melt the ice than had the sunlight continued on to depth. Here the bloom correlated strongly with shoaling of the pycnocline bringing reduced turbulent mixing which increased residence time in the surface layer and so light available to photosynthetic plankton.

While an upper layer of snow can block transmission, frequent leads in this weaker ice open and refreeze (initially without any snow cover) creating significant areas of reasonably transparent ice becomes available on the lead surfaces. An algae like Phaeocystis, well-adapted to dim and variable light intensity, can then flourish during long spring days despite ice drift and cold temperatures, to the point the bloom severely depletes available nitrogen to a depth of 50 meters (2nd image below).

The overall nitrogen cycle in the Arctic is very complex (see doi:10.1038/ncomms13145). Ferric iron is not a rate-limiting essential nutrient in the Arctic as it is in the Southern Ocean. Nitrogen depletion by Phaeocystis will diminish melt season diatom blooms that do sink to depth “with far-reaching repercussions on bloom timing and composition, strength of the biological carbon pump and energy flow through Arctic marine food webs”.

Another notion, floated by climato-optimists, is that while blooms are bad for surface water heating and ice bottom melt, they more than make up it with deep carbon sequestration. In this view, a blue Arctic ocean provides a game-changing offset for atmospheric emissions. However this concept is wishful thinking for Phaeocystis blooms — little fixed carbon dioxide makes it down to seafloor sediment but instead adds to near-surface opacity.

Prior to the RV Lance, an under-ice Phaeocystis bloom in May fell into the ‘unknown unknowns’ category of positive feedbacks contributing to global climate change, whereas ocean-wide blooms in a post-apocalyptic Arctic remain ‘known unknowns’ not considered ripe for inclusion into climate models until mid-century. As the biogeochemistry of the Arctic Ocean is already impossibly complex, it is delusional to think its rapid future change can be modeled in any meaningful way (but see doi: 10.1002/gbc.20055).

Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ice
P Assmy et al Jan 2017
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5244362/ free full text, summarized above

Effects of an Arctic under-ice bloom on solar radiant heating of the water column
T Taskjelle et al Jan 2017 DOI: 10.1002/2016JC012187 free full text

The deposition of solar energy in the upper Arctic Ocean depends on the composition of the water column. The May 2015 bloom led to significant changes in the inherent optical properties (IOPs) of the upper ocean. Simulations are used to investigate the change in depth-dependent solar heating of the ocean after the onset of the bloom, for wavelengths in the region 350–700 nm. Effects of clouds, sea ice cover, solar zenith angle, as well as the average cosine for scattering of the ocean inclusions are evaluated. An increase in energy absorption in the upper 10 m of about 36% is found under 25 cm ice with 2 cm snow relative to pre-bloom conditions with implications for ice melt and growth in spring. Thicker clouds and lower sun reduce the irradiance available, but lead to an increase in relative absorption.

Altered inherent optical properties and estimates of the underwater light field during an Arctic under-ice bloom of Phaeocystis pouchetii
AK Pavlov JGR Apr 2017 DOI 10.1002/2016JC012471

Absorption and scattering in the upper 20 m of the water column at visible wavebands increased 3x and 10x relative to pre-bloom conditions. Absorption by colored dissolved organic matter  2x. Total absorption by phytoplankton particles increased 10x. The ratio between photosynthetically active radiation and downwelling planar irradiance below sea ice reached 1.85. Our findings could help to improve light parameterizations in primary production models.

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead
HM Kauko et al Jun 2017 DOI: 10.1002/2016JG003626

The Arctic Ocean is rapidly changing from thicker multiyear to thinner first-year ice cover with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will result in more frequent leads covered by newly formed ice with little snow cover. We studied a refrozen lead 0.27m thick in drifting pack ice, measuring downwelling incident and ice transmitted spectral irradiance, colored dissolved organic matter, particle absorption, ultraviolet-protecting mycosporine-like amino acids and chlorophyll in melted sea ice samples (which are troubled by osmotic shock artifacts). Leads are important for phytoplankton growth by acting like windows into the water column.

The seeding of ice-algal blooms in Arctic pack ice: the multiyear ice seed repository hypothesis
LM Olsen et al Jun 2017 DOI: 10.1002/2016JG003668

The physical properties and ice algal community composition was investigated in the three different ice types during the winter-spring-summer transition. Algae remaining in sea ice surviving the summer melt season are subsequently trapped in the upper layers of the ice column during winter and may function as an algal seed repository.

Once the connectivity in the entire ice column is established as a result of temperature-driven increase in ice porosity during spring, algae in the upper parts of the ice are able to migrate towards the bottom and initiate the ice-algal spring bloom. Furthermore, this algal repository might seed the bloom in younger ice formed in adjacent leads.

This mechanism was studied in detail for the {blue]often dominating ice diatom Nitzschia frigida{/blue].The proposed seeding mechanism may be compromised due to the disappearance of older ice in  regime shift toward a seasonally ice-free Arctic Ocean.

rboyd

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Re: The 2017 melting season
« Reply #2032 on: June 14, 2017, 07:47:22 PM »
Thankyou A-team, had to read this a number of times to get some level of understanding. My main take-aways:

- "As the biogeochemistry of the Arctic Ocean is already impossibly complex, it is delusional to think its rapid future change can be modeled in any meaningful way". General humility and the usage of the precautionary principal, rather than eco-optimism should be our guide

- Organisms will tend to trap heat near the underside of thin ice, increasing the rate of bottom melt

- Hopes for a Blue Arctic to foster algal blooms that will sequester large amounts of carbon dioxide are misplaced

Ice Shieldz

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Re: The 2017 melting season
« Reply #2033 on: June 14, 2017, 09:57:35 PM »
What's notable about this system is how long it's forecasted to linger in the same vicinity. As mentioned, the Laptev Sea looks to see most of the action. Considering the ice-free expanses in the Laptev and the fractured nature of the pack extending well into the CAB, i can't help but think that we'll see some serious waves from all of this.

Below is a surface wind gfs forecast starting in 2 days and ending in 5 days.

jplotinus

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Re: The 2017 melting season
« Reply #2034 on: June 14, 2017, 10:47:48 PM »
Tiksi is in the path of the cyclone. Folks there may need to hunker down a bit.


Neven

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Re: The 2017 melting season
« Reply #2035 on: June 14, 2017, 10:54:05 PM »
Slightly off-topic, but it looks like Global sea ice area could hit a record low maximum soon, beating last year (graph from Wipneus):
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Greenbelt

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Re: The 2017 melting season
« Reply #2036 on: June 15, 2017, 12:04:16 AM »
Looks like the 12z ECMWF show the low bottoming out just a bit under 980mb. To me it's not the intensity of the wind breaking ice so much as the long duration of the event, which could pull lots of ice from the central arctic toward the Atlantic, perhaps raising extent at first but maybe also positioning more ice to where it will be more easy to melt in July and August.

In the long range, both GFS and ECMWF indicate the the low persists in slightly weaker form and drifts toward the pacific. That could maybe help preserve some ice to encouraging close during peak sun height, but maybe also pull in warm air from the pacific?



Thomas Barlow

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Re: The 2017 melting season
« Reply #2037 on: June 15, 2017, 01:44:41 AM »
On the other hand, the forecasted cyclone this month isn't surrounded by any strong high pressure systems.
Yes, makes sense. Nothing for it to feed off.

Tony Mcleod

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Re: The 2017 melting season
« Reply #2038 on: June 15, 2017, 01:55:25 AM »
Slightly off-topic, but it looks like Global sea ice area could hit a record low maximum soon, beating last year (graph from Wipneus):

Also the global maximum probably swinging from early November to mid-June,
- how to geo-engineer a dipole. ???

DrTskoul

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Re: The 2017 melting season
« Reply #2039 on: June 15, 2017, 02:33:56 AM »
Slightly off-topic, but it looks like Global sea ice area could hit a record low maximum soon, beating last year (graph from Wipneus):

I hope the global sea ice budget does not enter a new phase ( following last year's trajectory ) - the global albedo will see a step change.
“You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.”
― Richard P. Feynman

Tigertown

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Re: The 2017 melting season
« Reply #2040 on: June 15, 2017, 05:30:36 AM »
Updated this again as the openings are getting bigger each day. Worldview has been so cloudy.
CLICK IMAGE Zoom         12th-14th

jdallen

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Re: The 2017 melting season
« Reply #2041 on: June 15, 2017, 07:35:48 AM »
Thankyou A-team, had to read this a number of times to get some level of understanding. My main take-aways:

- "As the biogeochemistry of the Arctic Ocean is already impossibly complex, it is delusional to think its rapid future change can be modeled in any meaningful way". General humility and the usage of the precautionary principal, rather than eco-optimism should be our guide

- Organisms will tend to trap heat near the underside of thin ice, increasing the rate of bottom melt

- Hopes for a Blue Arctic to foster algal blooms that will sequester large amounts of carbon dioxide are misplaced
Thank you as well, A-Team.  My take away is similar to rboyd's.  While the lack of potential carbon sequestration is disappointing, it's a side show to our long term concerns.  More concerning is the potential amplifying effect of increased plankton and organic material at shallow depths on heat capture.  Simply put, more heat caught closer to the surface means that much more redirected to the ice.

Pity we can't yet quantify it... 5%?  10% more?  Even 1% is going to be highly disruptive, especially when we are so terrifyingly close to a some boundary condition in the system.
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jdallen

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Re: The 2017 melting season
« Reply #2042 on: June 15, 2017, 07:43:07 AM »
Updated this again as the openings are getting bigger each day. Worldview has been so cloudy.
CLICK IMAGE Zoom         12th-14th

I would be fascinated to see an explanation for this, as the current visible images from Worldview really don't show any hint of a hole.  Here's a shot of the region; the "hole" *should* be in the lower right quadrant of the image.

Lots of very messed up ice, but no hole.
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Tigertown

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Re: The 2017 melting season
« Reply #2043 on: June 15, 2017, 08:12:28 AM »
@jdallen
I think the hole that opened up on the 12th was a temporary drop in concentration for the area of concern, caused by the mobility of the ice. I was not in this latest post trying to imply anything regarding it. It is circled in the first frame of the gif simply because I did not save the original for the 12th and wanted to do the gif for three days instead of two to show the progress of the other openings, such as the Kara, Laptev, Hudson, and some in the Beaufort. There have been so many comments to the effect that nothing is happening, and therefore, the need to demonstrate that the open water areas are subtlety getting bigger.

Now, I will see if I can find that bottle of white-out. ;)

Andreas T

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Re: The 2017 melting season
« Reply #2044 on: June 15, 2017, 09:11:21 AM »
@jdallen
I think the hole that opened up on the 12th was a temporary drop in concentration for the area of concern, caused by the mobility of the ice. I was not in this latest post trying to imply anything regarding it. It is circled in the first frame of the gif simply because I did not save the original for the 12th and wanted to do the gif for three days instead of two to show the progress of the other openings, such as the Kara, Laptev, Hudson, and some in the Beaufort. There have been so many comments to the effect that nothing is happening, and therefore, the need to demonstrate that the open water areas are subtlety getting bigger.

Now, I will see if I can find that bottle of white-out. ;)
You seem to do very well in convincing yourself without that bottle. That you don't convince other people as well should make you look at the information that they present to you.
If you look at worldview images in the near IR bands clouds show up well, by clicking from one satellite to the other their movements over few hours can be seen and patterns in the ice which can be seen through thinner clouds can often be detected.
https://go.nasa.gov/2tpaJae
There simply is no opening in this place  (about 165W 77N)
There is a darker shade of red in the 3,6,7 band images which indicates the beginning of melt / wetting of the surface (no darker blue in 7,2,1) This is what the AMSR sensor also picks up, we have seen this many times and taking this in isolation will mean you are getting the wrong picture.
And no, I am not saying that nothing is going on, and I have not seen comments which claim that, just that its not what you think it is. Not the same  if you look carefully.

johnm33

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Re: The 2017 melting season
« Reply #2045 on: June 15, 2017, 10:57:18 AM »
I suspect the 'hole' at 160W 77nN is caused by upwelling, melt then rapid refreezing fooling the sensors.

Cook

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Re: The 2017 melting season
« Reply #2046 on: June 15, 2017, 12:27:53 PM »
What an amazing graphic, John, thank you for contributing with that.

I think this is a year of unusual deep snow and therefore, due to insulation and warm temperatures, unusually thin ice. The ice is probably more vulnerable to melting from below than from above, at least for the time being. Now that the snow must be melting/sublimating and the ice melting from below in much of the arctic I expect the cliff will be seen sooner rather than later, especially with a slow moving low likely to churn ice around and probably mix warmer saltier waters up.

seaicesailor

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Re: The 2017 melting season
« Reply #2047 on: June 15, 2017, 12:53:36 PM »
Thanks for the graph John, but I think the drop in SSS has more to do with Hycom predicting start of bottom melt in those areas than anything else. Usually comes accompanied by a drop in salinity.
It is striking though, that circular area.
Btw Hycom does not show any other dramatic change there, no thickness or SST or concentration.

johnm33

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Re: The 2017 melting season
« Reply #2048 on: June 15, 2017, 01:58:00 PM »
sis "Btw Hycom does not show any other dramatic change there, no thickness or SST or concentration."
Looking at the other animations there seems to be a repetitive wave formation that arises and 'points' at the area of interest, https://www7320.nrlssc.navy.mil/hycomARC/beaufort.html  best seen on 'ice strength' or 'ice concentration' it pretty much follows the arc of the continental shelf, but perhaps twice as far from the coast.

Tigertown

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Re: The 2017 melting season
« Reply #2049 on: June 15, 2017, 04:35:11 PM »
Andreas T
There simply is no opening in this place  (about 165W 77N)
I am simply not trying to say there is.
There may have been one there for a moment in time when the sat passed over on the 12th or it could have been a glitch. Not There now.
The white-out that I was joking about was for the mark that I made. You just really entirely misconstrued what I posted.
« Last Edit: June 15, 2017, 04:46:47 PM by Tigertown »