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A-Team

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Re: The 2016/2017 freezing season
« Reply #100 on: September 23, 2016, 04:31:45 PM »
Here is AMSR2 for the CAA for 01-22 Sept 2016, along with areas for estimating input of ice from the Central Arctic Basin. The necessary masks are provided; the bar at top is the original sea ice concentration palette, as are map colors. The bottom animation shows the set-up for the flux gate calculation, with residual open water (darkest blue) removed.

The channel area shown in the animation is 851,000 km2. The defining boundaries of 'Arctic Ocean' are indicated by the dark blue and taken at 14.1 mkm2; however the origin, accuracy, datum, and boundaries for that number is unclear.

I used a (complicated) new script for merging text and imagery to put in the dates; that will be described in a bit over in the developer forum.
« Last Edit: September 23, 2016, 05:10:20 PM by A-Team »

A-Team

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Re: The 2016/2017 freezing season
« Reply #101 on: September 23, 2016, 06:13:07 PM »
Nares and Fram export over the same date range, 01-22 Sep 2016, at native AMSR2 'large' scale with zero and 100% sea ice concentration colors replaced for clarity, along with three days of Modis 3-6-7 of 21-23 Sept 2016 whose first two dates can be compared with the last two AMSR2.
« Last Edit: September 23, 2016, 06:25:20 PM by A-Team »

BornFromTheVoid

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Re: The 2016/2017 freezing season
« Reply #102 on: September 23, 2016, 06:57:23 PM »
Using the 5 day NSIDC extent, the cumulative extent change for September has just gone positive. This is the earliest date that this has occurred since 1996. This is all the more impressive given that up to the 9th, we had the 4th largest cumulative extent loss on record.
An overall increase in extent occurs in about 2 thirds of all previous Septembers, but in just 7 of the last 15.

Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #103 on: September 23, 2016, 11:11:30 PM »
MODIS confirms there's lots of (what looks like) open water in McClure Strait:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201617-images/#CAA
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Re: The 2016/2017 freezing season
« Reply #104 on: September 24, 2016, 08:04:42 AM »
MODIS confirms there's lots of (what looks like) open water in McClure Strait:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201617-images/#CAA

What strikes me about that image is how much it shows heat in the water disintegrating ice at the margins.
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Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #105 on: September 24, 2016, 10:12:38 AM »
The other side of Kap Morris Jesup is looking a bit crumbly too:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201617-images/#CAB
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Lord M Vader

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Re: The 2016/2017 freezing season
« Reply #106 on: September 24, 2016, 11:48:12 AM »
From NSIDC data, it seems that this is the fastest freezing that have been seen since 1996. One problem to this very quick refreezing is how much snow that have been falling onto the ice? Most of the snow during the Arctic winter is, as we know, falling during the fall months. For example, Kotelny Island which belongs to the New Siberian Islands, gets an average of 46 mm of precipitation during September to November. Eureka in Canada gets about 21 mm during the fall.

A thick snow cover can be good and bad for the next melting season. A thick snow cover isolates well and the ice growth is lower. OTOH, a thick snow cover is good if low pressure dominated weather starts the melting season of 2017.

The point is: how good, or bad, is it to have a very quick refreezing of the "main" Arctic basin? I.e the areas with sea ice that are not melting away every single year.

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Re: The 2016/2017 freezing season
« Reply #107 on: September 24, 2016, 12:37:10 PM »
  That's a very good question on snow cover. If it insulates the ice this early then surely the dominant effect would be to minimise thickening during the freeze season? That would be bad for the 2017 melt season.

  The storms keep on rolling in. As shown below, there are currently 4 storm centres in the Arctic Basin, with the strongest having a low pressure of ~983 hPa. Yet another storm with a similar minimum pressure is predicted to arrive in around 4 days time.


  Two lines of questions for those who have watched the Arctic weather more closely than I during past freeze seasons:

1) is it normal to have as many storms, one after the other, during the beginning of the freeze season? If not, how unprecedented is the current situation; and

2) what are the likely effects and the likely consequences for the rest of the freeze season and the 2017 melt season? For example. would they be expected to dump a lot of snow on the ice? How significantly would they be mixing up the halocline and adding salt to the surface? Are they at least partly responsible for the quick initial freeze-over this year?

A-Team

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Re: The 2016/2017 freezing season
« Reply #108 on: September 24, 2016, 04:01:45 PM »
Weird how so many people posting away on the ASI Blog on the 2016 melt season never so much as glance at the 2016 melt season forum. It seems some are able to intuit the state of the ice w/o reference to observational data.

Yet view counts reach ~5000 over time so perhaps they do look but are baffled by data presentation; I've been assuming the animations are self-explanatory (just time lapse photography) but apparently not. However a number of people here definitely get it.

From some years as professor of mathematical physics, I am ok with the fact that the public has no clue what a metric is, never mind gradient and divergence (2nd term calculus). Still, it does not seem like rocket science to realize that from mickey mouse reductive integrals like extent, it is impossible to recover the map of the ice, even approximately -- a great many different distributions have the same outcome. Better to stick with the ice which is far too complex a substance for this approach.

Below are a couple more ways of looking at the transition season. Observe vigorous melt continues through September 23rd below the Wrangel arm. Big Block has also persisted to the 23rd though it is not picked up every day by AMSR2. There must have been hellacious winds to have blown so much ice eastward in the CAA channels and lower CAB, the effect extends over thousands of km.

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Re: The 2016/2017 freezing season
« Reply #109 on: September 24, 2016, 08:18:49 PM »
What strikes me about that image is how much it shows heat in the water disintegrating ice at the margins.


A very clear image of Banks Island arrived overnight:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201617-images/#CAA

Spot the difference from yesterday:
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Cate

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Re: The 2016/2017 freezing season
« Reply #110 on: September 25, 2016, 12:18:53 AM »
Hmm, let's see. Banks Island was white on Sept 12 under clear skies---looked snow-covered to me. The snow was there until Sept 20 and then started to disappear. Sept 23 shows lots of bare ground again, with snow only on what I assume is higher ground. Open water all around. Is this all normal, what you would expect for this time of year?   

slow wing

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Re: The 2016/2017 freezing season
« Reply #111 on: September 25, 2016, 03:16:50 AM »
Very informative plots, thanks A-Team! The re-freeze is impressive.

... There must have been hellacious winds to have blown so much ice eastward in the CAA channels and lower CAB, the effect extends over thousands of km.
  It's much too fast for wind-blown ice, which will typically travel at 5-10% of the wind speed.

  Instead, the water near to the ice is seen to be more susceptible to freeze-over. Speculating on some potential reasons:
  - fresher water, as is where ice has recently melted (& maybe with some residual ice still there)?
  - less windy near the ice?
  - colder water &/or air near the ice?

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Re: The 2016/2017 freezing season
« Reply #112 on: September 25, 2016, 08:14:00 AM »
Hmm, let's see. Banks Island was white on Sept 12 under clear skies---looked snow-covered to me. The snow was there until Sept 20 and then started to disappear. Sept 23 shows lots of bare ground again, with snow only on what I assume is higher ground. Open water all around. Is this all normal, what you would expect for this time of year?

I'm surprised to see that Banks Island is circumnavigable this late in September. From memory, it seems there's less ice in the NW Passage right now than usual, but I could be wrong.

For the last five years, I've observed the remains, if any, of ice in the vicinity of Baffin Island. Usually there are some remnants of ice that didn't totally melt over the summer. For instance, last year in Coronation Gulf, there was a remnant of ice in the upper portion of the Gulf that remained. This is the first year that I can remember, that all water surrounding Baffin Island is free of ice.
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Re: The 2016/2017 freezing season
« Reply #113 on: September 25, 2016, 12:38:48 PM »
Very informative plots, thanks A-Team! The re-freeze is impressive.

... There must have been hellacious winds to have blown so much ice eastward in the CAA channels and lower CAB, the effect extends over thousands of km.
  It's much too fast for wind-blown ice, which will typically travel at 5-10% of the wind speed.

  Instead, the water near to the ice is seen to be more susceptible to freeze-over. Speculating on some potential reasons:
  - fresher water, as is where ice has recently melted (& maybe with some residual ice still there)?
  - less windy near the ice?
  - colder water &/or air near the ice?

From the travels of O buoy 14 we know that it has been transported from the open ocean into the strait over the last month.  Started off in open water and then met up with the ice and was swept into the strait with it.

slow wing

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Re: The 2016/2017 freezing season
« Reply #114 on: September 25, 2016, 12:53:06 PM »
Very informative plots, thanks A-Team! The re-freeze is impressive.

... There must have been hellacious winds to have blown so much ice eastward in the CAA channels and lower CAB, the effect extends over thousands of km.
  It's much too fast for wind-blown ice, which will typically travel at 5-10% of the wind speed.

  Instead, the water near to the ice is seen to be more susceptible to freeze-over. Speculating on some potential reasons:
  - fresher water, as is where ice has recently melted (& maybe with some residual ice still there)?
  - less windy near the ice?
  - colder water &/or air near the ice?

From the travels of O buoy 14 we know that it has been transported from the open ocean into the strait over the last month.  Started off in open water and then met up with the ice and was swept into the strait with it.
Yep, thanks for this and sorry, A-Team, I may have been posting at cross-purposes to you. When you talked about blowing ice "eastward" and for thousands of km I thought you were referring to the re-freeze heading in the direction of Siberia. On re-reading, it appears you were instead talking about eastward within the CAA channels.

 Yes, it's true the winds this melt season have been extraordinary - indeed unprecedented in the record if I'm not mistaken.

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Re: The 2016/2017 freezing season
« Reply #115 on: September 25, 2016, 08:32:23 PM »
With regards to the quick refreeze, please tell me if I'm right in thinking that the lower the minimum, the more likely we'll see a faster initial rate of refreeze? Simply because there's more open water available for refreeze, being exposed to the coldest temperatures found closer to the pole? And that's if refreeze is being measured purely by daily growth, rather than absolute ice area. If we're talking about how many days after minimum a given year reaches a certain sea ice area, then the low minimum shouldn't help them be faster to the line in that race surely?

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Re: The 2016/2017 freezing season
« Reply #116 on: September 25, 2016, 09:39:50 PM »
With regards to the quick refreeze, please tell me if I'm right in thinking that the lower the minimum, the more likely we'll see a faster initial rate of refreeze? Simply because there's more open water available for refreeze, being exposed to the coldest temperatures found closer to the pole? And that's if refreeze is being measured purely by daily growth, rather than absolute ice area. If we're talking about how many days after minimum a given year reaches a certain sea ice area, then the low minimum shouldn't help them be faster to the line in that race surely?
Your thinking is based on good premises.  I'd only differ with your last conclusion.  More initial open water at this juncture will permit more rapid increases in extent and area, but do not necessarily mean specific area and extent milestones will be hit by a specific date.  In short, derivative measures like  rate of refreeze are more likely to be increased, but not necessarily raw scalar measures like extent and area.

I have mixed feelings about what we are seeing.  While on the one hand it is reassuring to see coverage recovering, on the other, I'm aware that this dramatically changes thermal transfer, reducing greatly the rate at which heat can escape from the ocean out of the atmosphere.

Trying to decide which I'd prefer - faster refreeze or longer open water - is a lesser of evils one, where even which one is less evil is unclear.  Later refreeze means less time for substantial ice to thicken.  Earlier refreeze means more of this season's heat trapped at high latitudes is carried over to next season to accelerate the start of melt.

Recent changes in atmospheric flow make things even worse.  With the slowing and deepening of Rossby waves as we've seen over the last few years, more heat and moisture is being pulled into the Arctic at mid-winter, and cold air displaced south.  Both the mass transfer of heat and the additional moisture in the atmosphere (coincidentally amplifying retention of heat as a very effective GHG...) will seriously impede ice growth.

I'm concerned also at the lack of ice in peripheral seas as well.  This may be another amplification; that is, that because of reduced albedo, places like the Beaufort, Chukchi, Barents and Kara, and to a lesser degree the Laptev, ESS and Greenland Sea - have spend more time taking up insolation.  At this time of year, even as far north as 75 degrees of latitude will get as much as 1.3 megajoules/3.6KWH a day of exposure.  Normally most of that would get bounced back out of the atmosphere, but now a significant fraction of it will be getting picked up by water.  That's far from enough to prevent the switch over to refreeze, but very much changes the heat exchange dynamic for this time of the year.
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Re: The 2016/2017 freezing season
« Reply #117 on: September 25, 2016, 10:56:23 PM »
EOSDISWorldview provides a wonderful view of the Fram-ward movement of the ice north of Greenland over the last 2 weeks . Wish I had the skills to share . Most of the ice has moved 100km toward oblivion and with the forecast winds supporting accellerating export the melting season continues even as area etc grow . bc .
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Re: The 2016/2017 freezing season
« Reply #118 on: September 26, 2016, 12:06:00 AM »
At this time of year, even as far north as 75 degrees of latitude will get as much as 1.3 megajoules/3.6KWH a day of exposure.

Where the hell did you get that figure from? If it where true the ocean would probably warm up and not freeze.
At this time of the year open ocean can only absorb around 0.75 kWh/m2

jai mitchell

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Re: The 2016/2017 freezing season
« Reply #119 on: September 26, 2016, 06:16:54 AM »
At this time of year, even as far north as 75 degrees of latitude will get as much as 1.3 megajoules/3.6KWH a day of exposure.

Where the hell did you get that figure from? If it where true the ocean would probably warm up and not freeze.
At this time of the year open ocean can only absorb around 0.75 kWh/m2

that is a little under 3 megajoules per m^2
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Re: The 2016/2017 freezing season
« Reply #120 on: September 26, 2016, 09:03:52 AM »
The conversation reminded me of this elucidatory article by Mark Brandon:

http://mallemaroking.org/arctic-ocean-sensible-heat-loss/
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Re: The 2016/2017 freezing season
« Reply #121 on: September 26, 2016, 09:14:24 AM »
At this time of year, even as far north as 75 degrees of latitude will get as much as 1.3 megajoules/3.6KWH a day of exposure.

Where the hell did you get that figure from? If it where true the ocean would probably warm up and not freeze.
At this time of the year open ocean can only absorb around 0.75 kWh/m2
that's highly dependent on latitude. Mine is arough calc of available daily insolation at solstice at 75N.  And I very much disagree that it's enough to keep warming up the water.  It's not really quite enough to balance loss out of the top of the atmosphere. It's only about 1/3rd of what's available at peak there and is rapidly decaying. I'll happily accept others correcting my rough math, but I don't think I'm far off.

Let me add, my point isn't so much about more energy entering. Rather about less energy leaving.
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Tealight

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Re: The 2016/2017 freezing season
« Reply #122 on: September 26, 2016, 12:35:08 PM »
At this time of year, even as far north as 75 degrees of latitude will get as much as 1.3 megajoules/3.6KWH a day of exposure.

Where the hell did you get that figure from? If it where true the ocean would probably warm up and not freeze.
At this time of the year open ocean can only absorb around 0.75 kWh/m2

that is a little under 3 megajoules per m^2
that's highly dependent on latitude. Mine is arough calc of available daily insolation at solstice at 75N.  And I very much disagree that it's enough to keep warming up the water.  It's not really quite enough to balance loss out of the top of the atmosphere. It's only about 1/3rd of what's available at peak there and is rapidly decaying. I'll happily accept others correcting my rough math, but I don't think I'm far off.

Let me add, my point isn't so much about more energy entering. Rather about less energy leaving.

OK I think the misunderstanding was caused by your unit conversion. 1.3 megajoules is 0.36kWh and not 3.6kWh. I only paid attention to 3.6kWh and didn't check your conversion.

On second note the difference between radiation on top of the atmosphere and on the surface in the arctic is huge at this time of the year and surface albedo isn't very relevant. Water also has a high albedo at current angles of incidence.

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Re: The 2016/2017 freezing season
« Reply #123 on: September 26, 2016, 02:23:46 PM »
An interesting new paper:

Atmospheric conditions during the Arctic Clouds in Summer Experiment (ACSE): Contrasting open-water and sea-ice surfaces during melt and freeze-up seasons.

The Arctic Clouds in Summer Experiment (ACSE) was conducted during summer and early autumn 2014, providing a detailed view of the seasonal transition from ice melt into freeze-up. Measurements were taken over both ice-free and ice-covered surfaces, near the ice edge, offering insight to the role of the surface state in shaping the atmospheric conditions. The initiation of the autumn freeze-up was related to a change in air mass, rather than to changes in solar radiation alone; the lower atmosphere cooled abruptly leading to a surface heat loss. During melt season, strong surface inversions persisted over the ice, while elevated inversions were more frequent over open water. These differences disappeared during autumn freeze-up, when elevated inversions persisted over both ice-free and ice-covered conditions. These results are in contrast to previous studies that found a well-mixed boundary layer persisting in summer and an increased frequency of surface-based inversions in autumn, suggesting that our knowledge derived from measurements taken within the pan-Arctic area and on the central ice-pack does not necessarily apply closer to the ice-edge.


What do you suppose happens if a large percentage of the "pan-Arctic area" resembles the MIZ?

A helpful hint - Also check ResearchGate.
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seaicesailor

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Re: The 2016/2017 freezing season
« Reply #124 on: September 26, 2016, 03:45:18 PM »
With regards to the quick refreeze, please tell me if I'm right in thinking that the lower the minimum, the more likely we'll see a faster initial rate of refreeze? Simply because there's more open water available for refreeze, being exposed to the coldest temperatures found closer to the pole? And that's if refreeze is being measured purely by daily growth, rather than absolute ice area. If we're talking about how many days after minimum a given year reaches a certain sea ice area, then the low minimum shouldn't help them be faster to the line in that race surely?

I have mixed feelings about what we are seeing.
...
 Earlier refreeze means more of this season's heat trapped at high latitudes is carried over to next season to accelerate the start of melt.
...
Is there anything written out there about this? I just can't find it.

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Re: The 2016/2017 freezing season
« Reply #125 on: September 27, 2016, 11:58:11 AM »

I have mixed feelings about what we are seeing.  While on the one hand it is reassuring to see coverage recovering, on the other, I'm aware that this dramatically changes thermal transfer, reducing greatly the rate at which heat can escape from the ocean out of the atmosphere.

True but, as ever, the heat is a double edged sword in the Arctic. Simply getting the heat impacts the next season.

If it remains it will increase surface melt, but, again, it could also be radiated out through the thinner ice if it has no snow cover.

However if it evaporates out during the autumn in a late freeze event, it will create more moisture in the cooling atmosphere to drive local snow cover which will insulate the ice from more cooling.  Also, should those clouds remain during the deep winter, it will insulate the Arctic from the worst effects of the winter.

All of which leads to more melt in the following season.

The main message being the more heat absorbed in each melting season, the worse it will be for the following melt season, regardless of how it freezes up.

This winter season we dip deeper into the Solar Minimum and we switch to La Nina.  All of which will have an impact over and above the events during the re-freeze.

My bet is more, but weaker, ice than last year, followed by a 2007/2012 event next year.  Followed by a 2008/9 follow up in the freezing and melting seasons beyond.

But that's just a guess.
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seaicesailor

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Re: The 2016/2017 freezing season
« Reply #126 on: September 27, 2016, 10:10:17 PM »
Reading around, I find very instructive Chris Reynolds takes on the problem of most of the heat excess being vented out during refreezing, see for instanve, http://dosbat.blogspot.com.es/2011/07/arctic-sea-ice-free-this-decade.html?m=1
with special reference to Tietsche et al 2011 simulations
http://onlinelibrary.wiley.com/doi/10.1029/2010GL045698/full
in a number of posts.
Seems to me what we are witnessing is a fast refreeze for three reasons: cold weather from north; lots of marginal zones with ice and colder water that are first to refreeze; and, a litlle of initial fast propagation due to wrinkled ice edge, which increases the initial interface lenght of ice->water prone to quicker refreezing. Add plenty of divergent drift within the pack.
My first assumption is that this fast refreeze does not lock up any trapped heat. It just means areas where heat in mixed layer was lower to start with will refreeze sooner. Nothing to trap beneath it. Then, warmer areas will take longer to refreeze, and then will eventually do when they reach freezing temperatures. Nothing special thermodynamically.
Can some heat be trapped for next season? Maybe. For instance a later pulse of warmer Bering inflow water would lose more heat if it remains in open water than if it forms a pool beneath already frozen area. Likewise there is this complicated mechanism of a layer of fresher ice sealing saltier water beneath. Many other complicated things out there.
But overall I will assume them not significant for next season unless I am pointed to a good scientific resource indicating otherwise.
No seeding of refreezing with sort of a catalystic process. Which is the agent that catalizes the freezing may I ask?
Early snow cover may play a factor on limiting heat losses, but simple 1D heat equation shows that 10 or 20 cm of snow layer has a limited temporal effect (a week) on isolating ice from outside plummeting temperatures. 50 cm is another story, but you don't get that until Spring, and by then it becomes really ice-protective.
I can be wrong that nobody here pointed to scientific work, indicating massive heat can be trapped to really affect next season because of fast refreeze (except, as I said, maybe to reduce heat loss from incoming ocean currents; but for that, peripheral seas must be sealed with ice and that may still take quite some time).
What I find very worrying for next season is the low volume, low MYI survived, and the shape of the pack cannot be worse, if massive Fram export during Winter and early melting in Pacific side happen next year.

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Re: The 2016/2017 freezing season
« Reply #127 on: September 27, 2016, 11:18:30 PM »
I'm not sure what this means apart from maybe ongoing loss of the freshest fraction of water



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Re: The 2016/2017 freezing season
« Reply #128 on: September 28, 2016, 03:01:35 AM »
I believe the biggest story of this melt season is the highly fractured and dispersed nature of the remaining ice. This fast freeze will lock these relatively small MYI flows into a highly dispersed pattern, waiting for the next melt season.

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Re: The 2016/2017 freezing season
« Reply #129 on: September 28, 2016, 05:31:48 AM »
Just read in the IJIS thread that we broke the 5M km2 plane today. It definitely looks like the momentum is for the freezing side now, and not slowing down anytime soon.

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Re: The 2016/2017 freezing season
« Reply #130 on: September 28, 2016, 01:44:51 PM »
Trying to better understand the heat exchange of the arctic ocean with the atmosphere I stumbled upon the graph attached. It clearly shows that the lower levels of the oceans are cooling. The strongest cooling pulses seem to be correlated with strong melting seasons.   I imagine this has to do with cold stored in thick ice that melts in the surface lowering the temperature underneath.

I would love to see a graph like this but for the arctic ocean. A colder ocean should make for a faster refreeze, at least while there is ice left on the arctic.
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Re: The 2016/2017 freezing season
« Reply #131 on: September 28, 2016, 02:00:35 PM »
Sentinel 1A imagery of the Lincoln Sea from September 26th:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201617-images/#CAB
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Re: The 2016/2017 freezing season
« Reply #132 on: September 28, 2016, 03:32:55 PM »
Forecast for Oct 8 ECMWF.
Won't probably realize but, 934 hPa ? ? ?

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Re: The 2016/2017 freezing season
« Reply #133 on: September 28, 2016, 05:43:42 PM »
Seaicesailor: if so, it is the remnants of the tropical cyclone Chaba. And TC interaction with the midlatitudes is always a tough nut.

The quick refreezing we have seen so far make me wondering how much impact the two intensive cyclones back in August had on the SSTs and the salinity. Any ideas?

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Re: The 2016/2017 freezing season
« Reply #134 on: September 28, 2016, 06:30:05 PM »
The latest cyclone has just crossed the coast into the East Siberian Sea with a MSLP of 976 hPa
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Tigertown

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Re: The 2016/2017 freezing season
« Reply #135 on: September 29, 2016, 07:20:41 AM »
The Wrangel arm's back and it's been hittin' the gym.


Thomas Barlow

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Re: The 2016/2017 freezing season
« Reply #136 on: September 30, 2016, 02:15:14 AM »
Beaufort Sea Sept. 14 and 29.

Andreas Muenchow

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Re: The 2016/2017 freezing season
« Reply #137 on: September 30, 2016, 06:12:16 AM »
The latest cyclone has just crossed the coast into the East Siberian Sea with a MSLP of 976 hPa

Where may I find this surface map and, I suspect, its daily updates? I am very nervous to be heading into that Wrangel Arm of sea ice leaving Nome via Sikuliaq on Oct.-15 to return a month later. I suspect we may take a beating at that "bad" time of the year.
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jai mitchell

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Re: The 2016/2017 freezing season
« Reply #138 on: September 30, 2016, 06:24:16 AM »
latent heat

massive mid-latitude blocking patterns are once again forcing moisture and heat energy into the arctic cell.  This appears to be partially due to an increase of atmospheric water vapor post the latest El Nino?  We shall see if this continues.  I hate to imagine what the El Gygytgyn +8C from today at 400 ppm CO2 looks like, but it is starting to feel like an Eocene arctic future.

http://weather.utah.edu/index.php?runcode=2016092918&t=gfs004&r=NH&d=DT



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werther

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Re: The 2016/2017 freezing season
« Reply #139 on: September 30, 2016, 09:14:57 AM »
When one with great interest in the geophysics of our planet is on this for over ten years, one starts to get some sense for the short term and chaotical variance of all processes. 
What is going on since 7 September has a direct relation to the structure-loss of the complete Arctic sea ice pack. It is mobile and dispersed. The open ocean waters in between, having a thin, sweeter top layer, is soon ready to support formation of nilas and guard fresh fallen snow against dissolving. The satellite sensors pick this up as extent growth. They did so in earlier years too, nothing new here except for the intensively broken up structure of the pack nowadays.
This  extent growth doesn’t tell us much about the real state of the ice nor about  the nature of the coming winter season.

binntho

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Re: The 2016/2017 freezing season
« Reply #140 on: September 30, 2016, 12:26:23 PM »
Werther, I agree!

Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #141 on: September 30, 2016, 06:12:02 PM »
SMOS is up and running again, and reporting some "interesting" results:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#SMOS
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Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #142 on: September 30, 2016, 06:18:06 PM »
Where may I find this surface map and, I suspect, its daily updates?


Sorry Andreas. I "almost always" include a link, but not on this occasion. Actually there are 6 hourly updates from Environment Canada:

http://weather.gc.ca/analysis/index_e.html

Other people's mileage may vary, but for forecasts I head for MeteoCiel first since you can compare all sorts of sources:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=0&carte=1

Re the Sikuliaq, see also: http://forum.arctic-sea-ice.net/index.php/topic,1385.0.html

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

A-Team

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Re: The 2016/2017 freezing season
« Reply #143 on: October 01, 2016, 11:12:08 PM »
Here are some updates through the end of the month and some comparisons to the same period for the four earlier years available, of which 2012 is most remarkable.

Both melt and refreezing are continuing as of Sept 30th, depending on the region. Various 'boundary operators' are used below to highlight active areas, that is, the changing sea ice found sandwiched open water (darkest blue on AMSR2 3.1k UHH) and areas of solid ice (95-100% concentration).

It is only on a correctly constructed product, all too rare, that this is possible to do at all. (Not saying here this sea ice concentration product is fabulously accurate, just that the map would display them properly if they were.) In math 101 terms, palette assignment on the netCDF does not commute with projection to map coordinates, so the product ends up hopelessly dithered (like the mind of the matlab client).

The two main things to watch in coming months are timely refreeze (or not) of the Beaufort and  Polar Front from Svalbard to Severnaya Zemlya. The latter retreat -- and its causes -- have been the subject of numerous 2015-16 papers.

Part of the problem is that Atlantic Water is now 4ºC warmer than water just under the ice, the most extreme in two millennia. The AW is now completing its circuit with far less heat than it brought in, with far more loss than can be explained by double diffusion. So some turbulent processes are at work. This AW water is fully capable of melting all the ice regardless of what is going on with surface weather.
« Last Edit: October 01, 2016, 11:40:04 PM by A-Team »

oren

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Re: The 2016/2017 freezing season
« Reply #144 on: October 02, 2016, 12:00:10 AM »
A-Team thank you for these beautiful and instructive comparisons.

slow wing

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Re: The 2016/2017 freezing season
« Reply #145 on: October 02, 2016, 02:38:46 AM »
Agree, thanks A-Team. Also very interesting about the Atlantic water.

As background, there is an introduction on that topic on the Wikipedia page, which is very well done:
https://en.wikipedia.org/wiki/Arctic_Ocean

A screen shot of the start of that section is appended:

Tigertown

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Re: The 2016/2017 freezing season
« Reply #146 on: October 02, 2016, 02:55:57 AM »
Who bumped the thermostat?



Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #148 on: October 02, 2016, 12:10:02 PM »
The two main things to watch in coming months are timely refreeze (or not) of the Beaufort


Prompts this cross post:



The refreeze off Banks Island. Plus this:

http://GreatWhiteCon.info/2016/09/is-the-northwest-passage-freezing-or-melting/

If Lars is watching, is there any chance of Hamburg processing a bit more of 2012?
« Last Edit: October 02, 2016, 12:45:18 PM by Jim Hunt »
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #149 on: October 02, 2016, 12:15:00 PM »
Also very interesting about the Atlantic water.


See also the new paper from Jim Thomson:

http://forum.arctic-sea-ice.net/index.php/topic,1222.msg90939.html#msg90939
Reality is merely an illusion, albeit a very persistent one - Albert Einstein