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Old 22-03-2018, 08:43   #256
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Re: Northwest Passage - 2018

A very confronting visualization was just created by NASA:

https://youtu.be/Vj1G9gqhkYA
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Old 22-03-2018, 12:53   #257
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Re: Northwest Passage - 2018

Quote:
Originally Posted by Erik de Jong View Post
A very confronting visualization was just created by NASA:

https://youtu.be/Vj1G9gqhkYA
that was from October of 16
I was hoping for current but thanks for posting this
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Old 22-03-2018, 16:05   #258
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Re: Northwest Passage - 2018

Newhaul has been focusing on ice thickness. Here are the trends:



Arctic Sea Ice Thickness from ICESat and CryoSat-2: The maps show Arctic sea ice thickness at the end of the winter melt season: 2004 through 2008 from ICESat, and 2011 through 2014 from CryoSat-2. The graph shows trends in sea ice thickness in winter and summer. Image courtesy Ron Kwok, Jet Propulsion Laboratory, adapted from Kwok and Cunningham 2015.

Longer historical trends



Arctic Sea Ice Thickness Comparisons: These graphs from Kwok and Rothrock 2009 compare sea ice thickness observations from submarine records and ICESat observations over time. The bar chart (left) compares sea ice thickness for six Arctic regions. The time series (right) shows submarine sonar measurements compiled in studies published 2008 and 2009 (designated as RA), and ICESat observations. Error bars on the February-March measurements appear as vertical blue bars.
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Old 22-03-2018, 16:07   #259
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Re: Northwest Passage - 2018

It seems the spring melt has started.

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Old 22-03-2018, 16:21   #260
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Re: Northwest Passage - 2018

Quote:
Originally Posted by jackdale View Post
Newhaul has been focusing on ice thickness. Here are the trends:



Arctic Sea Ice Thickness from ICESat and CryoSat-2: The maps show Arctic sea ice thickness at the end of the winter melt season: 2004 through 2008 from ICESat, and 2011 through 2014 from CryoSat-2. The graph shows trends in sea ice thickness in winter and summer. Image courtesy Ron Kwok, Jet Propulsion Laboratory, adapted from Kwok and Cunningham 2015.

Longer historical trends



Arctic Sea Ice Thickness Comparisons: These graphs from Kwok and Rothrock 2009 compare sea ice thickness observations from submarine records and ICESat observations over time. The bar chart (left) compares sea ice thickness for six Arctic regions. The time series (right) shows submarine sonar measurements compiled in studies published 2008 and 2009 (designated as RA), and ICESat observations. Error bars on the February-March measurements appear as vertical blue bars.
it appears that over the last ten or so years we have begun to increase the volumes again.
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Old 22-03-2018, 16:25   #261
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Re: Northwest Passage - 2018

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Originally Posted by jackdale View Post
It seems the spring melt has started.

so it would seem however it also appears we are gaining volumes at a pass more inline with winter freeze up than nearing the end of the winter season.
DMI Modelled ice thickness
Including an apparent thickening in the Canadian archipelago as well.
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Old 22-03-2018, 16:37   #262
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Re: Northwest Passage - 2018

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so it would seem however it also appears we are gaining volumes at a pass more inline with winter freeze up than nearing the end of the winter season.
DMI Modelled ice thickness
Including an apparent thickening in the Canadian archipelago as well.
Ice volume will start to decline mid April.
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Old 22-03-2018, 17:06   #263
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Re: Northwest Passage - 2018

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Ice volume will start to decline mid April.
I know they will start to decline I just think its kind of abnormal how fast it has been increasing over the last 3 weeks
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Old 23-03-2018, 08:10   #264
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Re: Northwest Passage - 2018

Quote:
Originally Posted by Erik de Jong View Post
A very confronting visualization was just created by NASA:

https://youtu.be/Vj1G9gqhkYA
A rather effective visualization, though a repost, see post 38. Certainly doesn't hurt to see it again though...



Perhaps this might be a good time to remind everyone of something about models.

They are, by nature and description, all wrong. They are representations, very, very useful, but are only meant to illustrate, give meaning, and help to understand complex situations or systems, it seems primarily to aid in making predictions.

The natural progression for models is to improve; the tendency is to get more accurate as time goes by (though the US seems to be declining in this aspect, for various reasons), as accuracy improves, the predictive ability (generally) improves with it. Five-day weather and hurricane track forecasts are good examples of this...

This brings us round to a couple of models that seem most talked about on this thread; sea ice extent and volume.

Since extent (I believe area is what is actually used, but let's not confuse the issue) is a 2 dimensional, surface feature, it can be 'modeled' directly via observation, visually or electromagnetically (I know, vision is electromagnetic, but I'm referring to the not-visible E/M spectrum...)

Volume, on the other hand, cannot be measured visually or directly EMly and must be measured manually or by radar (also E/M, but the thickness is inferred by comparison of ice height above sea level and sea level!) and sonar. If I remember correctly, the volume models are currently using all three (plus others), and the plot I saw (can't remember the date, but it was fairly recent) showing the sample tracks revealed to me an almost alarming lack of data points, especially when compared to the modeled area. (but what do I know?)

Of course that may or may not matter; the test is how well the model describes reality.

Given what we know about how these particular models are assembled, it would seem prudent to me to put about a third less confidence in the accuracy of volume models, purely on the basis of the uncertainty of the 'third-dimensional measurement' alone...


Regarding the recent 'spike' in volume, as Sailoar noted previously, most of this 'volume' is made up of recently frozen ice, probably a result of rapid surface freezing of leads, polynyas and areas of open water exposed by wind, the (comparatively) warm just-under-the-surface water and massively fractured sea ice Arctic-wide...

You can actually see this happening in the animation of the center-east end of the NW passage here

https://worldview.earthdata.nasa.gov...v=1.5&al=false

but be forewarned; it will probably take a bit to load...


So, whilst the late-season jump in volume looks 'good' in the model, it's timing and composition is likely to lead to its' being ephemeral at best...


Obviously just my very-layman's understanding, so corrections and additions are welcome...
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Old 23-03-2018, 09:39   #265
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Re: Northwest Passage - 2018

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Of course that may or may not matter; the test is how well the model describes reality.
None of them are anywhere near reality.
Ice extent is nothing more than some bookkeeping of square miles. They take a square of a mile by a mile, if 15% or more of the surface of that square mile is covered with ice, it counts as a full square mile covered in the statistics.

In other words, 85% of open water is still considered "ice covered".
What I have seen over the years, is that the number of areas with 50-85% ice coverage are increasing, so the ice is actually disappearing (much) faster than the graphs for ice extent are indicating.
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Old 23-03-2018, 15:49   #266
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Re: Northwest Passage - 2018

NSIDC has verified that the maximum was reached on St. Patrick's day.

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On March 17, 2018, Arctic sea ice likely reached its maximum extent for the year, at 14.48 million square kilometers (5.59 million square miles), the second lowest in the 39-year satellite record, falling just behind 2017. This year’s maximum extent is 1.16 million square kilometers (448,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles).

The four lowest seasonal maxima have all occurred during the last four years. The 2018 maximum is 60,000 square kilometers (23,200 square miles) above the record low maximum that occurred on March 7, 2017; 40,000 square kilometers (15,400 square miles) below the 2015 and 2016 maxima (now tied for third lowest); and is 190,000 square kilometers (73,400 square miles) below the 2011 maximum, which is now fourth lowest.
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Old 24-03-2018, 06:34   #267
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Re: Northwest Passage - 2018

Canada’s overworked icebreaker fleet waiting for relief | Herald-News

...Canada has an overworked fleet of icebreakers built nearly 40 years ago...

On Jan. 18 Prime Minister Justin Trudeau announced that the federal government was starting negotiations with Quebec’s Davie Shipyard to lease icebreakers until Canada can build new ones. Dubbed “Project Resolute” by the shipyard, Davie is offering to convert the MV Aiviq, a heavy icebreaker built in 2012 for use on Shell’s Alaska drilling campaign, and three Norwegian-built medium icebreakers to serve the coast guard on an interim basis.

“When government can’t or won’t put money in to replace equipment, you end up in situations like this,” said Ken Hansen, a retired Canadian navy commander. “This is crisis planning, when government resorts to things like special contracts to Davie. Unusual purchases and repairs are a sign of illness in the system.”...
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Old 24-03-2018, 07:01   #268
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Re: Northwest Passage - 2018

More commercial shipping through the Arctic - even in winter.

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Until now, most scientific focus has been on a trend of shrinking Arctic sea ice in summer, which is opening shipping routes from the Pacific to the Atlantic and allowing oil and gas exploration even as it harms indigenous peoples and wildlife such as polar bears.

Now, “things are increasingly about the winter time,” said Tor Eldevik, a professor at the University of Bergen’s Bjerknes Centre for Climate Research.

The winter retreat means ever bigger areas are ice-free year round, especially in the Barents Sea north of Russia and Norway which is becoming more like the Atlantic Ocean, he said.

The vast Shtokman natural gas field, north of Russia, is in an area that is now ice-free even in the depths of winter – helping Gazprom if it ever develops the find. The region was ice-bound in winter until the early 1980s, Eldevik said.

Shipping company Teekay said a tanker loaded a first cargo of liquefied natural gas at a terminal in Arctic Russia and traveled to France in January 2018 – the first ship to make such a winter voyage without an icebreaker.
Arctic Ocean Ice Near Record Low for Winter, Boost for Shipping – gCaptain
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Old 26-03-2018, 06:54   #269
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Re: Northwest Passage - 2018

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Originally Posted by Tricolor View Post
Richard I think you have to start it yourself and make clear its about boats.. BTW Dauntless still in winter sleep?
Sleeping like a baby in the hot Mexican sun.

Yes, will do.
Jimbunyard has a very nice explanation of models.

I see we have another two pages of same old same old.
Ice volume. What a joke. I think there are a few here who don't even understand the Arctic or how ice grows and melts.

We need to stop responding to the 21st century Know Nothings
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Old 27-03-2018, 04:46   #270
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Re: Northwest Passage - 2018

The Arctic’s carbon bomb might be even more potent than we thought | Washington Post

Scientists had predicted that most of the greenhouse gases released from the carbon-rich, frozen soils of the Arctic would be less-potent carbon dioxide, rather than more-potent methane. Research published in Nature Climate Change suggests that waterlogged wetland soils, where oxygen is not prevalent, will produce a considerable volume of methane. Previous studies had not examined warming waterlogged Arctic soils over a long period of time. This study discovered that it took three years or more for the methane-generating microorganisms to really start producing. So much methane was produced in the experiment, the researchers calculated that the impact of greenhouse gas emissions from wet soils, or wetlands, will be higher than from drier soils, where carbon dioxide should indeed be the top gas released.
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