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Jim Hunt

A very interesting winter, followed by a very interesting summer! And the show's not over until the fat lady sings.

I'm not about to make such a prediction, but I wonder if Lewis and/or Neven would care to predict the value (and date?) of the summer 2017 minimum for one or more Arctic sea ice metrics?

Here's some more suggestions from the ASIF:

http://forum.arctic-sea-ice.net/index.php/topic,2126.0.html

iceman

At this late date and under near-neutral conditions, it shouldn't be too hard to pick a number. But I'm still baffled by the factors in opposition: concentration vs. thickness distribution, among others. Thinking on a V-shaped extent minimum, which would require compaction continuing beyond next week and a further push from bottom melt. So I'll guess 4.1 million km2 for the JAXA daily min you linked to.

Interestingly, on the other poll's measure of NCSID September average extent, the SIPN August Report's median of 4.54 million km2 is up slightly from July's, but still low enough for a 3rd-place finish.
https://www.arcus.org/sipn/sea-ice-outlook/2017/august

Artful Dodger

Hi Lewis,

Good summary of the year-to-date. Thank-you for all your effort!

Slight errata: you wrote "first-year ice ... is more prone to melting than multi-year ice, partly because of lower brine content."

Of course, that should read "higher brine content" for 1st-yr sea ice.

Brine rejection continues for about 3 yrs by when MYI seaice is mostly brine-free and is highly resilient to melting. Most MYI is lost through transport out of the Arctic via the transpolar drift, rather than melting out in-situ.

Or at least it used to work that way before the southern Beaufort sea turned into the place MYI ice goes to die. Oh, the changes we have seen in our life times.

Cheers,
Lodger

Hans Gunnstaddar

http://www.bbc.com/news/science-environment-41037071

'First tanker crosses northern sea route without ice breaker'

The specially-built ship completed the crossing in just six-and-a-half days setting a new record, according to the tanker's Russian owners.

"The 300-metre-long Sovcomflot ship, the Christophe de Margerie, was carrying gas from Norway to South Korea.

Rising Arctic temperatures are boosting commercial shipping across this route."

Jim Hunt

Hans - There's much more on that story on the ASIF:

http://forum.arctic-sea-ice.net/index.php/topic,854.msg123499.html#msg123499

Hans Gunnstaddar

Interesting thread, thanks Jim.

Hans Gunnstaddar

https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_nic.png

This is about the arctic so hopefully on topic enough, although not directly related to the guest post.

Indulge me for a moment for an interesting observation. If you look at the above link you'll notice a round wide open expanse of water along the Gakkel Ridge, in an area of ice concentration that is otherwise at much higher concentrations.

In a YouTube Video I saw a while back there was mention and a map showing a spot along the Gakkel Ridge that has in recent years supposedly been emitting mantle methane, and I think it coincides with that open water location. My question is this; Once the seasonal melt reaches a certain point in which the ice has been weakened, could rising methane bubbles push away the ice to form a round shaped open area? I ask in part because that same round area has been there for a few weeks now. Below is a map showing the Gakkel Ridge.

http://4.bp.blogspot.com/-jywSP0Wq3yc/UmYWKs8k1aI/AAAAAAAALsA/IR6NvaBd_zc/s1600/Arctic+Ocean.jpg

Rob Dekker

Thank you Lewis, for this nice overview of prediction models.

Early in the melting season, we saw this large negative anomaly of volume, which was caused by an exceptionally warm winter.

Luckily, the summer registered a rather cool melting season, which I think is partially caused by that large positive land snow anomaly that Rutgers Snow land recorded :
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6
Some 4 million km^2 of land snow more in June than last year.
That has got to leave a significant dent on absorbed heat in the Northern Hemisphere.

So I think that the negative volume anomaly in winter and the positive land snow anomaly in summer balanced each other out and we end up with a September SIE that is neither exceptionally low nor exceptionally high.

Other years we may not be so lucky.

Wade Smith

Not exactly the right place to talk about this, but it's semi-relevant.

[No, it's not the right place to talk about this and so I'm deleting the other comments as well; you can discuss Harvey over on the ASIF; N.]

Wade Smith

Wait, sorry, but what is that? I don't know how to get to that site...

[It's here; N.]

iceman

Good catch Lodger, thanks for the correction. I wonder whether there is some way to derive data from the Tschudi ice age model to quantify the change in MYI melting within the Arctic vs. being exported. The animation on Climate.gov certainly supports your point.
https://www.climate.gov/news-features/videos/old-ice-arctic-vanishingly-rare

Rob, generally agree with your assessment, though it omits the unknown (and possibly greater) influence of snow cover over sea ice. Would that we had better observational data.

Rob Dekker

Lewis, thanks.
One point of clarification : I include land snow cover in my model since it clearly affects albedo and thus the heat budget over the Northern Hemisphere.
Snow on ice affects the albedo much less and thus in my opinion is not that important for the heat budget.

Rob Dekker

As Wipneus reports on the ASIF :

According to NSIDC NT sea ice concentration, extent in 2017 is currently the 8th lowest, area is 7th.

Looks like we are not going to see any records broken this year.


Hans Gunnstaddar

https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_visual.png

Ok, everybody ignored my mantle methane, Gekkal Ridge theory about a round open water area. Well, it's still there. Look at the above link and then enlarge the view (control +) and you'll see it's about as round as could be expected considering that area is surrounded by high concentration ice. If it isn't methane bubbling up opening that part of the ice or clathrate methane, remaining in that exact same location week after week, then what is causing it?

Jim Hunt

Hans - You may be interested in this?

http://forum.arctic-sea-ice.net/index.php/topic,1834.msg125795.html#msg125795

There's little support for the polynya occurring every year, which restricts the space of possible explanations.

Hans Gunnstaddar

"A case could be made that 2012 and perhaps 2013 had a persistent polynya in a fairly similar place to 2017's. However there's little support for the polynya occurring every year, which restricts the space of possible explanations."

How about seismic activity along the Ridge is not constant, but instead random.

https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_visual.png

https://volcanohotspot.wordpress.com/2017/06/16/1999-2001-eruption-sequence-in-the-gakkel-ridge/

Coincidentally the polynya just happens to be located directly above the Gekkal Ridge? I think this is one to keep an eye on.

There is a woman with a very distinctive voice (but I can't recall her name) who did a YouTube Vid on GW, and I can't find it now, but she suggested mantle methane was rising along the Gekkal Ridge and had a map showing the location and it is the same location as the polynya. I'm going to keep trying to find it.

Rob Dekker

Hans, About this polynya, I presented a different theory, that it may be caused by the Coriolis forces driving the Atlantic warm water upward while making a U-turn at that very location against the Gekkal Ridge :
http://forum.arctic-sea-ice.net/index.php/topic,1834.msg125728.html#msg125728

Hans Gunnstaddar

Hi Rob, yes, saw that first in the link Jim provided and also in your link. That certainly is possible.

Would be nice to go to that location and do some on site research to try and confirm, but haven't got access to a research vessel - lol.

By the way, congrats on your more accurate prediction of this years melt vis a vis above average snowfall. CAB ice held on Pacific side much better than I expected with how fast it was declining earlier. Wonder if the repeating 5 year cycle would have hit a new low if there had been average snowfall.

This is all good though because it dodges a bullet or as you put it a possible cannonball with how low volume had gotten during winter. More time to deploy more renewables.

AnotherJourneybyTrain

Congratulations to Rob,

"You stole the show .."

I still think there will be some sort of knock-on-effect from the low volumes experienced earlier in the year but I suppose this year simply becomes a time for re-engineering of theory.

(..back to the drawing board...)

Hans Gunnstaddar

https://www.youtube.com/watch?v=a9PshoYtoxo

Ok, I found that YouTube Video by Jennifer Hynes (distinctive voice) and part of it is on Mantle methane. Take a look first at 1:08:40 which shows a methane emissions chart with high levels of emissions from the Laptev Sea (from earthquakes occurring along the Gekkal Ridge, resulting from increased seismic activity from isostatic rebound of Greenland from less mass holding it down). Watch it from there if you like or you can jump to 1:11:35 and see a red dot she's pointing to on a map where there have been high levels of methane emissions from the Gekkal Ridge. That spot appears to line up well with the polynya in question (from earlier posts).

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